United States
Environmental Protection
Agency
Industrial Environmental Research
Laboratory
Cincinnati OH 45268
EPA 600 2-79-067
March 1979
Research and Development
&ER&
Environmental and
Pollution Aspects of
Coal Slurry
Pipelines
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
8. "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the ENVIRONMENTAL PROTECTION TECH-
NOLOGY series. This series describes research performed to develop and dem-
onstrate instrumentation, equipment, and methodology to repair or prevent en-
vironmental degradation from point and non-point sources of pollution. This work
provides the new or improved technology required for the control and treatment
of pollution-sources to meet environmental quality standards.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/2-79-067
March 1979
THE ENVIRONMENTAL AND POLLUTION ASPECTS
OF COAL SLURRY PIPELINES
by
R. R, Faddick
Colorado School of Mines
Golden, Colorado 80401
Grant No. R804614-01-0
Project Officer
John F. Martin
Extraction Technology Branch
Industrial Environmental Research Laboratory
Cincinnati, Ohio 45268
INDUSTRIAL ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
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DISCLAIMER
This report has been reviewed by the Industrial Environmental Re-
search Laboratory, U.S. Environmental Protection Agency, and
approved for publication. Approval does not signify that the
contents necessarily reflect the views and policies of the U.S.
Environmental Protection Agency, nor does mention of trade names
or commercial products constitute endorsement or recommendation
for use.
11
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FOREWORD
When energy and material resources are extracted, processed, converted,
and used, the related pollutional impacts on our environment and even on our
health often require that new and increasingly more efficient pollution con-
trol methods be used. The Industrial Environmental Research Laboratory -
Cincinnati (lERL-Ci) assists in developing and demonstrating new and improved
methodologies that will meet these needs both efficiently and economically.
This report contains an assessment of the environmental and pollution
aspects of coal slurry pipelines. This study was conducted to supply infor-
mation to EPA on the environmental impacts associated with the design, con-
struction and operation of a coal slurry pipeline. Further information on
this subject may be obtained from the Extraction Technology Branch, Resource
Extraction and Handling Division.
David G. Stephan
Director
Industrial Environmental Research Laboratory
Cincinnati
111
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ABSTRACT
With the anticipated increases in coal consumption in the
next decade, greater demands will be made on existing transporta-
tion systems to move to market the abundant reserves of coal in
the United States. Conventional transportation modes such as
rail and barge will have to expand their capabilities by over-
coming those shortages that may exist in labor, capital, and
equipment. Simultaneously, lesser known systems such as coal in
water (slurry) pipelines will have to share the transportation
load.
The environmental impact of a coal slurry pipeline system
may occur during design, construction, or operation and mainten-
ance; and it may involve any of three areas—slurry preparation,
transportation, and separation. The evidence suggests that the
environmental and pollution aspects of coal slurry pipelines as
a system are less than alternative transportation modes. Meth-
ods are suggested to enhance the selection of better design,
construction, and operation techniques to provide a balance of
engineering, economic, and environmental considerations.
The major expansion of coal production is expected to take
place in the West, where, traditionally, water has held top pri-
ority. The exportation of water as a liquid carrier for coal
will provoke many political, legal, and economic confrontations.
The water issue, although predominant, cannot be fully addressed
because of unknown long-term effects of water withdrawal from
deep groundwater sources.
A possible solution may be the advent of energy slurries con-
sisting of hydrocarbon solids and liquids that require less
water in their processing, take advantage of economical pipeline
transportation, and eliminate costly dewatering circuits. The
environmental and pollution aspects of energy slurry pipelines
are expected to be similar to those of oil pipelines.
This report was submitted in fulfillment of Grant No.R804616-
01-0 by the Colorado School of Mines under the sponsorship of
the U.S. Environmental Protection Agency. This report covers
the period July 12, 1976 to March 31, 1978, and work was com-
pleted as of April 30, 1978.
IV
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CONTENTS
Foreword .....................
Abstract ..................... iv
Acknowledgments .................. vi
1. Introduction ............... 1
2. Alternate Energy Transportation Modes . . 14
3. Water Quantity and Quality ........ 31
4. Dewatering ................ 48
5. Pipeline Corridor Selection and Con-
struction ................ 59
6. Operation and Maintenance ........ 66
7. Epilogue ................. 77
References .................... 83
Appendices
A. Major Pipeline Installations ....... 91
B. Water Quality Standards ......... 95
C. Guidelines for Process, Design and Con-
struction, and Operation of Slurry Pipe-
lines .................. 105
v
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ACKNOWLEDGMENTS
The author wishes to thank the Project Officer, John F.
Martin, for his assistance, and James J. Gusek, graduate student
in Mining Engineering at the Colorado School of Mines, for his
tireless efforts in compiling and annotating the reference lit-
erature.
VI
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SECTION 1
INTRODUCTION
Expansion and diversification of environmentally acceptable
U.S. energy sources have been widely called for by the media.
This call has been created by these circumstances:
1. the depletion of low-cost domestic oil and gas resources,
2. the high cost and heavy dependence on foreign oil and gas
supplies, and
3. the present unreliability of nuclear systems.
These factors have produced a sharply increased interest in
returning to coal, since coal is the most plentiful source of
energy in the United States. In fact, we have nearly half of the
world's reserves of coal. Coal-bearing rocks, which are present
in 37 states, underlie some 13 percent of U.S. land.
U.S. coal resources, as estimated by the U.S. Geological
Survey (1), are much larger than our resources of oil and gas
combined. With these coal resources, the United States can pro-
vide many decades of fuel and hydrocarbon supplies to meet future
energy demands. The technologies for mining, washing, transport-
ing, and burning of coal are well known. Coal can be converted
into electricity, heat, and gas and, in the future, into heavy
liquids and light distillates to serve almost all the energy-
consuming markets.
In the United States, coal production faces some environ-
mental problems that in turn affect the cost and the availabil-
ity of coal. These environmental constraints are the following:
1. Land impacts: Land is altered by the method of mining used
e.g., surface mining depresses the topography.
2. Human resource impacts: There are health and safety risks
in surface and underground mining.
3. Air impacts: Air pollution is created by combustion by-
products such as fly ash and bottom ash.
According to the National Coal Association (2) U.S. coal
production will set a record high of 704 million tons in 1977,
a 5.8% increase over 1976 production (Table 1). These records
are finally surpassing the postwar boom year of 1947, when the
U.S. produced 631 million tons.
Table 1 shows U.S. coal production and consumption by mar-
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TABLE 1. UNITED STATES PRODUCTION AND CONSUMPTION
OF BITUMINOUS COAL 1947 —1977 *
(Thousands of Tons)
Year
1947
1952
1957
1962
1967
1970
1971
1972
1973
1974
1975
1976
1977
Elect. pow. Rail-
utilities roads
86,009
103,309
157,398
190,833
271,784
318,921
326,280
348,612
386,879
390,068
403,249
442,000
NA*
109,296
37,962
8,401
x+
X
X
X
X
X
X
X
(est) x
X
Coking Steel&roll- Cements Retail de-
coal ing mills mfg. liveries
104,800
97,614
108,020
74,262
92,272
96,009
82,809
87,272
93,634
89,747
83,272
85,000
NA
14,195
9,632
6,938
7,319
6,330
5,410
5,560
4,850
6,356
6,155
2,715
NA
NA
134,934
103,379
97,199
87,182
92,931
83,207
68,862
67,131
60,837
57,819
59,759
NA
NA
96,657
66,861
35,712
28,188
17,099
12,072
11,351
8,748
8,200
8,840
7,282
NA
NA
Total U.S.
consumption
557,243
418,757
413,668
387,774
480,416
515,619
494,862
516,776
556,022
552,709
556,301
597,000
NA
Total U.S.
production
630,624
466,841
492,709
422,149
552,626
602,932
552,192
595,386
591,738
601,000
640,000
665,000
704,000
* Source: U.S. Bureau of Mines (4)
x - discontinued.
NA - Not available.
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kets for selected years. Coal consumption in the United States
has declined almost 200 million tons between 1947 and 1958. The
comeback of coal in the 1960's was largely produced by develop-
ment in the electric utility fuel market, the coal industry's
only growing market.
In the early part of the century, coal supplied almost 80
percent of the nation's energy (Table 2). Shortly after World
War II coal provided less than 40% of our nation's energy when
railroads shifted from coal-fired steam locomotives to diesel en-
gines to avoid the problem of coal handling. At the same time,
home coal furnaces shifted to cleaner, more convenient, and en-
vironmentally acceptable sources of energy—oil and natural gas.
Western coal is expected to supply most of the increase in
U.S. coal production. For example, the Powder River Basin of
Wyoming is projected to produce 86 million tons per year by 1985
from a total of 21 mines. In 1975 there were only 5 active mines
there (3). Colorado produces about 7 million tons per year from
fewer than 40 mines.
Major breakthroughs in technology wil«l play a large role in
the future domestic markets of coal. Coal for the synthetic fuel
markets will be used in the early 1980's for the production of
synthetic pipeline gas, synthetic liquid fuels, and sulfur-free
clean coal for use in power utility plants, refineries, or other
industries.
Today there are many processes for synthetic fuel production
from coal. Some are at the laboratory bench scale stage, some
are at the pilot plant stage, and some are at the production
stage.
The National Academy of Engineering (6) estimated that coal
production in the United States by 1985 will be double the cur-
rent annual output of 670 million tons. Consumption was also
forecast and is shown on the next page.
TABLE 2. ENERGY SUPPLIES IN THE U.S.*
Source of
Energy
Coal
Petroleum
Natural gas
Hydro
Nuclear
1920
78%
14
4
4
—
1950
38%
39
18
5
—
1973
18%
46
31
4
1
Total 100%
100%
*Source: Ford. Foundation (5)
3
100%
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1985 consumption
Fuel: million tons/year
Coal solids (for utilities,
industries, and residences) 950
Synthetics 310
Total 1,260
From these figures, it is anticipated that the synthetic
fuel industry will be consuming about 25% of the total produc-
tion.
COAL TRANSPORTATION
Since coal is a source of energy, it must be transported to
the vicinity of use in one form or another either in its natural
state, as electricity, or as a refined product, as a gas or a
liquid. Currently the economics of coal utilization, particu-
larly as an energy source for electric power generation, favor
moving it and using it in its natural state (6).
In the United States there are four major modes of trans-
porting coal to markets in its natural form: railroads, barges,
trucks, and miscellaneous—including tramway, conveyors, slurry
pipelines (Table 3) .
The western states are expected to play an important part
as the United States approaches "Project Independence." Some
experts predict that annual consumption of western coal from Wyo-
ming, Colorado, and neighboring states will rise from 21 million
tons in 1971 to 362 million tons in 1980 (7). Because of the re-
moteness of western coal fields, and the low population density
of the western states, increased coal production will necessi-
tate movement to market by all of the existing transportation
modes. The railroads certainly cannot handle all of the in-
TABLE 3. COAL TRANSPORTATION MODES IN THE U.S. IN 1973*
Mode Percent
Railroads 52
Barges 27
Trucks 12
Miscellaneous:
(tramway, conveyor,
and private railroads) 8
'Slurry Pipelines 1
Total 100
*Source: U.S. Bureau of Mines (4)
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crease. Waterways are cheapest but limited geographically.
Moreover, there are no waterways in the West within a hundred
miles of the coal fields. Trucks are not economical for long
distance and large volumes. Therefore, slurry pipelines must
play an increasingly important role in transporting coal where
water is available. Alternate transportation modes are dis-
cussed in more detail in the next chapter.
Chemical Engineering (7) shows Steffes" projection that
railroads and slurry pipelines will transport almost equivalent
amounts of western coal by 1980, as shown, in the following:
Million of tons per year
Moved by rail for utilities
and industry 165
Moved by slurry pipelines for
utilities and industry 162
On site generation station (EHV) 20
Substitute Natural Gas (SNG)
from coal 15
Total . . 362
This anticipated growth in use of coal slurry pipelines pro-
vides the impetus for this study, which involves a closer look
at coal slurry technology, in particular its environmental and
pollution aspects. Technology will be examined first.
State of the Art
In a coal slurry pipeline, coal is mixed with about an equal
weight of water and pumped through a pipe. The coal and water
together are referred to as a two-phase (solids-liquid) system or
slurry. Pumping a two-phase system such as a coal slurry is much
more complex than pumping a single-phase such as water. The
mathematics describing the behavior of water under certain con-
ditions is very well established and has been so for more than a
century. Also, basic water properties do not vary significantly
from place to place. (The comparison of fresh water with sea
water is a possible exception.)
While water properties are fairly constant, coal properties
vary according to source and sometimes even within the same coal
seam. Coal properties in place include specific gravity, rank,
moisture content, ash content, volatiles, sulfur content, and
hardness. Additional properties observed once the coal is mined
are size and shape of coal particles, surface texture, amount of
entrapped methane, and size distribution. Size distribution de-
scribes the size range of coal particles—whether they are one
size or if there are varying amounts of powdery or lumpy par-
ticles generated when the coal is mined or crushed. Size distri-
bution is expressed as a percent passing through or retained on
sieves of different standardized hole sizes.
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Once the coal is mixed with water additional properties of
the slurry can be varied. The concentration of the coal present
in the water is an important variable, particularly since it rep-
resents the payload of the pipeline system. Other variables in-
clude the temperature and viscosity of the slurry. Viscosity is
a property measuring the fluidity of the slurry.
With the high variability of coal properties, it is easily
concluded that no two coal slurries are exactly alike, and this
is what has generally been observed. Though different coals will
have similarities within certain limits when mixed with water and
pumped in a slurry, no two slurries will behave identically when
pumped through identical systems. Each slurry has its own unique
hydraulic characteristics.
Coal Slurry Preparation, Transportation, and Separation
In the preparation stage coal is pulverized to a specified
size and is usually mixed with an equal amount by weight of water
The resulting slurry is pumped at about 1-1/2 to 2 meters per
second through a pipeline that is usually underground. Over long
distances the necessary flow is maintained by intermediate boos-
ter pump stations. At its destination the coal is removed from
the water by means of centrifuges, vacuum filters, or thermal
drying as required. Since the coal is saturated with water, the
two phases are not always easy to separate. The coal is used as
boiler fuel to generate electricity, and the clarified water is
beneficially consumed as a small part (about one-eighth) of the
power plant cooling requirement (8,9,10).
Pipelining solids in slurry form is now supported by sub-
stantial technology and is backed by the experience gained in
many commercial installations. Many materials can be slurried
and pumped through a pipeline, and their hydraulic behavior can
be fairly well predicted by the use of laboratory tests and com-
puter models so that a reliable design can be made. Designs must
be tested in loop systems when scaling to larger diameter pipes
is required. Technology of slurry pipelining is well developed
and so is the art of applying it. Though improvements are desir-
able, the necessary equipment is commercially available and ade-
quate.
Coal slurry hydraulics relate the many variables which must
be managed in order to attain a stable slurry. This stability
refers to: maintaining flow velocities low enough to keep power
requirements moderate and abrasion negligible yet high enough to
prevent deposition. Bedding can lead to pipeline plugging. How-
ever, most slurry systems are designed to minimize the chance of
plugs even in a rapid, unplanned shutdown such as a power outage.
Experience has shown that a slurry pipeline filled with a proper-
ly constituted slurry can be shut down and then restarted up to
four days later without difficulty (11). Restart time to full
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operation and slurry homogeneity was 2 to 3 minutes for the Ohio
pipeline (12).
To transport solids successfully in slurry form, enough ener-
gy in the form of turbulence must be imparted to the slurry to
keep the solids in suspension. It is important to have some pow-
der-fine material in the slurry to provide the viscosity which
supports the coarser particles at lower velocities. Nevertheless,
the operating velocity in the pipeline must be high enough to pro-
vide the necessary turbulence. If the velocity is not maintained
at this level, the coarser particles will tend to move toward the
bottom of the pipe, causing localized wear and increased risk of
plugging. Conversely, at high velocities, wear and excessive
pumping horsepower can also be problems. Hence, a slurry pipe-
line may be considered as having speed limits, both minimum and
maximum.
The speed limit aspect of slurry pipelines is one reason for
their complexity. It is a design constraint around which other
design parameters revolve. Pipe diameter determination is an ex-
ample of the complex interrelationships of system variables. As
pipe diameter increases, the capital cost of the line increases
almost parabolically because the cost is a function of the weight
of steel in the pipe (13). At the same time operating costs (per
ton of coal delivered) drop because friction losses are lower in
larger pipe. Combining the capital cost and operating cost curves
usually yields a horseshoe-shaped curve with a minimum total cost
related to a certain diameter. But this is cost at a fixed an-
nual throughput capacity. When the speed limit concept is added
to the economic examination, the "point" answer of minimum cost
becomes an "area" answer in which one of several points must be
eventually selected. Sometimes because of unique slurry proper-
ties the system must be operated at a higher level than the hy-
draulic minimum to make it more cost effective (Figure 1).
Even though the design method is unique and complex, from all
outward appearances the slurry pipeline itself is virtually iden-
tical to an oil or gas line. This pipe is conventional line pipe
coated to provide for external corrosion protection. Internal
coating has not been attempted commercially for slurry pipelines
but is being considered. The coal absorbs some oxygen reducing
internal corrosion, but sometimes a corrosion inhibitor must be
added to minimize this problem. The mechanism of corrosion also
can be found in conventional water pipelines as a coating of ox-
idized material (rust scale) on the inside of the pipe. The
addition of solids causes this coating to be eroded away as soon
as it forms in a corrosion/erosion synergistic effect which ac-
celerates internal wear. A small additional pipe wall thickness
is included in the design to provide for this problem. Wall
thicknesses generally range between 0.5 cm and 1.25 cm.
Every transportation system has its limitation. In addition
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oo
DOPT
PIPE DIAMETER D
FIXED COST BASED
ON CAPITAL INVESTMENT
FOR THE INSTALLED PIPE
PUMPING POWER COST
Figure 1. Optimum pipe diameter for a minimum total cost at a
fixed mass flow rate. (14)
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to the speed limit problem for pipeline operation, there is the
difficulty in slowing the flowrate when process requirements at
the terminal end of the slurry pipeline are low. An example of
this would be the reduced load of a power plant that has a tur-
bine-generator malfunction or a related problem. A coal slurry
pipeline handles this problem by maintaining constant communica-
tion with the power plant it feeds and can plan pumping with the
aid of a computer prediction model. Throughput can be reduced by
decreasing the concentration of coal, maintaining the design con-
centration but interspersing it with slugs of water , (batching),
or shutting down the pipeline. Another limitation may be allow-
able moisture content of the delivered coal. If the ultimate
process requires the use of dry material, then dewatering the
slurry and clarifying the water becomes an important consider-
ation and one that may be difficult and costly.
Past, Present, and Planned Pipelines
Slurry pipelines carry literally everything from A to Z—
from aluminum oxide to zinc oxide. Appendix A is a partial list-
ing of the larger slurry pipelines known to the author. The vast
majority of slurry pipelines emanate from the minerals industry.
Just a few originate from the agricultural and other non-minerals
industry. Most of the solids-carrying pipelines transport miner-
al tailings. Thus waste disposal is the prime use for slurry
pipelines. Slurry pipelines also transport mineral concentrates
or beneficiated ores, as well as raw ores.
The first recorded slurry pipeline appears to be one used in
gold placer operations in California in the late 1850's (15). (A
detailed history of slurry pipelines is given in the same refer-
ence.) Coal pipelines were mentioned in a patent application by
W.T. Donnelly of Brooklyn, N.Y., in 1904. In England, G.G. Bell
built a 200 mm diameter pipeline over 600 m long for unloading
barge coal hydraulically. In 1957 the Russians claimed in Ugol
that they had built the first long distance coal pipeline—300 mm
diameter, 61 km long, transporting 220 tph at 1.5 m/s (15).
The evolution of coal slurry pipelines in the United States
began in 1957 when a 250 mm diameter pipeline, 173 km in length,
was operated for six years, .delivering coal in slurry form from
Cadiz to the East Lake Generating Station near Cleveland, Ohio.
Rail tariffs had climbed to $3.47 per ton. The pipeline deliv-
ered coal at less than $3.00 per ton, which, included preparation
and dewatering costs. After six years the railroad succumbed
and lowered its tariff to $1.88/ton (16). The pipeline was then
mothballed but kept on call as a lever against the railroad.
In November 1970 the Black Mesa pipeline came on stream and
is still operating. The transportation cost was stated as $2.50
per ton in 1975 and $3.00 per ton in 1976 (9,17). Though 3.765
million tons of coal were transported in 1975 compared to 4.2
9
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million tons of coal in 1976, the increase in unit transportation
cost was due primarily to increased power costs. This pipeline
was built where no continuous trackage existed over the entire
route. Where a few rail crossings were necessary, these were
negotiated by the Black Mesa Pipeline Co. and the individual
railroad effected.
Continuing interest in the mid-seventies shows nearly a half
dozen coal slurry pipelines in the wings, much larger and longer
than their predecessors (Table 4)(18). The third slurry pipeline
system, Allen-Warner for Nevada Power Co., is expected to begin
service in 1983 (19). In this case, sufficient rail trackage
does not exist and the topography is too rugged for a unit train.
The pipeline system will consist of two parallel pipelines, each
feeding a separate power station. A common preparation plant at
the Alton coal field near Kanab, Utah, will feed the Warner Val-
ley power station near St. George, Utah; by 109 km of 300 mm dia-
meter pipe and 8 km of 200 mm diameter pipe carrying 2.27 million
tonnes* of coal annually. The second pipeline, consisting of 262
km of 550 mm diameter pipe and 30 km of 500 mm diameter pipe,
will carry 8.26 million tonnes of coal annually to the Allen pow-
er station near Las Vegas. Both pipelines utilize short di1-
stances of small diameter pipe to dissipate energy through in-
creased pipewall friction over excessively steep terrain.
Before the design of the Allen-Warner pipeline, Energy Trans-
portation Systems, Inc. (ETSI) proposed a 1661 km pipeline from
Gillette, Wyoming, to utilities near Little Rock, Arkansas. Al-
most 50 rail crossings would be required and this is where the
confrontation began. The railroads denied access, thus forcing
the quest for eminent domain by the Slurry Transportation Asso-
ciation, a lobby newly formed for this purpose.
In 1976 Houston Natural Gas and the Denver and Rio Grande
Western Railroad informed the State of Colorado of a proposed
coal slurry pipeline system (San Marco)(Figure 2). Nine million
tonnes of coal annually would be moved by rail from several Colo-
rado mines to Walsenburg, Colorado. Another 4.5 million tonnes
would arrive from Farmington, New Mexico, by slurry pipeline. A
water field in the San Luis Valley of Colorado would supply water
to the Farmington slurry preparation plant and to the Walsenburg
slurry preparation plant. Annual water requirements are esti-
mated at 12.34xl06nH (10,000 acre-feet). The combined 13.5 mil-
lion annual tonnes of coal would be slurried and pumped to Texas
with intermediate annual deliveries of 1.1 million tonnes to Ama-
rillo, a similar amount to a utility 112 km south west of Ama-
rillo, and 4.5 million tonnes to Temple. The remaining 6.8 mil-
lion tonnes would continue on to Angleton, south of Houston, op-
eration was to have begun at the end of 1979, but the securing
of water supplies in Colorado has been delayed by legal and po-
*Ton=short ton; tonne=metric ton
10
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TABLE 4. COAL SLURRY PIPELINES IN THE U.S.
Name
Consolidation*
Black Mesa
ETSI+
Houston
Nat. Gas
Salt River t
Nevada Power
Gulf Inter-
state
Montana/
Houston
Existing Lines
Origin/terminal Length Diameter Capacity
(km) (mm) (million
tonnes /An.)
Cadiz, Ohio to
Cleveland, Ohio 173 254 1.2
Kayenta, Ariz.
to Nevada 436 457 4.4
Planned Lines
Gillette, Wyo.
to White Bluff,
Arkansas 1661 965 23
Walsenburg, Colo.
to Houston, Texas 1864 203-711 13.6
Star Lake, N.M.
to St. Johns, Ariz. 288 406
Alton, Utah to
Arrow Canyon, Nev. 412 200-550 10.5
Gillette, Wyo. to
Boardman, Oregon 1280 762 14.5
Southern Montana
to Houston, Texas 2024* 1016 26
* Is not in operation at this time.
+ Energy Transportation Systems Inc.
t Cancelled.
# Estimated from the map (20).
11
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Line
A
B
C
D
E
Wl
W2
Length
km
355
466
107
624
312
88
267
Size
mm
406
711
200
660
508
508
305
Capacity
MMTPY
4.5
13.5
1.1
11.1
6.8
10,000
Ac. -ft.
Figure 2. Proposed Colorado-Texas (San Marco) coal pipelines,
12
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litical complications.
The existence of so many slurry pipelines attests to their
proven technology. However, the advent of the coal-water slurry
pipeline on the domestic scene has raised questions of eminent
domain, water usage, and environmental impact. Before examining
the latter two questions in detail, a comparison of other modes
of transporting coal will be made.
13
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SECTION 2
ALTERNATE ENERGY TRANSPORTATION MODES
COAL TRANSPORTATION
Though the United States is currently researching alternate
energy sources such as the fast breeder reactor, fusion, geother-
mal energy, wind power, and solar power, none of these can be
considered short-term solutions to the energy shortage (21).
They may be considered long-term solutions, however, while coal-
derived synthetic fuels may be regarded as intermediate solu-
tions. The short-term solution, it appears, will have to be
coal.
One problem surrounding domestic energy production is the
selection of the optimummethod of transporting the energy from
the producer to the consumer. Coal transportation trends have
changed and will change in future years (Table 5).
Pipelines will probably see additional growth as gasifica-
tion and liquifaction plants are built to produce synthetic fuels
from coal. Evidence is yet too sparse to conclude whether it is
more advantageous economically and environmentally to transport
coal to the area of consumption or to convert the coal to syn-
thetic fuels at the mine and pipeline them to the area of energy
consumption. Presently, pipelines move one-fourth of all the
freight tonnage, primarily oil, petroleum products, and natural
gas (23).
Period
TABLE 5. COAL TRANSPORTATION*
(Average Percent)
Rail
Barge
Truck
Slurry pipeline
'37-'40
•48-'51
•70-'73
1985(est.)
83.7
81.5
66.8
52
5.5
5.1
11.4
16
7.8
10.4
11.0
10
—
0.4
8
14
-------
Pipeline Safety
Safety has always been one of the major advantages of pipe-
lines. A Summary of Accidents Related t£ Non-Nuclear Energy,(24)
a U.S. Environmental Protection Agency Publication, examines the
safety of pipelines as follows (24):
a) Coal:
Transportation accidents account for 10-15% of mining
fatalities. In underground mining operations, hauling is
the most dangerous function. Although such accidents are not
frequent, they are severe. Coal is transported to the con-
sumer via rail, trucks, and slurry pipelines. These three
rank from most to least dangerous in terms of fatal injuries
per ICA2 BTU* equivalent tons shipped as follows: railroads
are most dangerous at 0.06 followed by trucks at 0.032 and
slurry pipeline at 0.0019.
b) Crude Oil:
Transportation of oil via tankers accounts for a greater
number of fatalities and injuries annually than transporta-
tion of oil via pipeline. Pipeline accidents number approxi-
mately 135 per year, and cause approximately one fatality and
one injury per year. Tanker accidents number approximately
640 per year and cause approximately 75 fatalities and 35 in-
juries per year.
c) Natural Gas and Liquified Natural Gas(LNG)
Almost all pipeline accidents can be attributed to cor-
rosion, damage by outside forces, construction defects, or
material failure. The Eighth Annual Report of Pipeline Safe-
ty summarized gas pipeline accidents during 1975. .[See
Tables 6 and 71 With a total of 1,373 failures this amounts
to 0.01 fatality per failure and 0.17 injury per failure.
Pipeline transportation poses a significant hazard to the
general public [only] when pipelines transect residential
and commercial areas.
According to statistics tabulated by the U.S. Department of
Transportation (25,26), most gas pipeline accidents (54% to 58%)
are the result of damage from outside sources. During the same
period (1972 and 1973), construction defects or material failures
accounted for 19.5% to 23.5% of the total failures. Table 8 sum-
*This amount of energy is equal to that required to run a 1000
MW power plant for approximately 300 hrs, or to that needed to
heat approximately 5000 homes for one season (October through
April) in a temperate climate.
15
-------
TABLE 6. NATURAL GAS ACCIDENT DATA*
Fatalities Injuries Fatalities Injuries
Technology /1012 BTU /1012 BTU /year /year
Pipeline
distribution 0.000040 0.0138 8 220
Extraction
offshore 0.000007 0.0030
onshore 0.000080 0.0040 16
Transmission
& gathering 0.000006 0.0010 6 17
Processing
natural gas
liquid
hydrogen
sulfide
0.000040
0.000002
0.0040
0.0020
3 921
*Source: Reference 24
TABLE 7. PIPELINE ACCIDENT DATA - 1975*
Non-employee Non-employee Employee Employee
Mode injuries fatalities injuries fatalities
Distribution 191 8 29 0
Transmission
& gathering 9_ 1 8_ 5
Total 200 9 37
*Source:Reference 24
16
-------
TABLE 8. GAS PIPELINE ACCIDENTS, 1972-73*
Accident Total no.
cause
1972:
Corrosion
Damage by
outside forces
Construction
defect or ma-
terial failure
Other causes
Total
1973:
Corrosion
Damage by
outside forces
Construction
defect or ma-
terial failure
Other causes
Total
-- - — r ' "~~
74
219
80
36
409
63
272
111
25
471
.MfK>«^^^«-^^— •^^^^•M^—A
Fatalities
Employ Non-employ
0
0
0
3
3
0
0
0
1
1
0
0
2
1
3
0
0
0
1
1
•HH^^^^BmMB-PBOHVIVPPBHIIItaBIPIVPVMBH
Injuries
Employ
0
8
4
11
23
1
0
0
2
3
^fc—^-^l-mnH
-------
marizes accident statistics for the transmission of natural gas
in 1972 and 1973.
Unit Trains
A unit train is basically a long train (almost 2 km) pulling
cars filled with one commodity that is going from one location to
another with no intermediate stops. In the case of unit trains
carrying coal the train is generally 90 to 110 cars in length,
each car containing about 90 tonnes traveling between a mine and
a consuming facility, usually an electric generating plant.
Two thirds of all the coal produced in this country now is
carried by rail. This traffic in coal brought the railroads
$2.1 billion in revenue in 1975—a 50% increase over the 1973
figure. Of the 400 million tons of coal carried by the railroads
in 1975, half was in unit trains. Coal accounted for 30% of all
tonnage in railroad freight in 1976 and contributed 13% to total
railroad revenues (27) . According to Scales (22) , this trend
will continue with the advent of increased coal production in the
West despite conpetition from coal slurry pipelines, mine-mouth
power plants, and gasification and liquefaction plants.
Unit trains have proved to be a competitive mode of trans-
porting materials since their inception in 1963 when a unit train
tariff undercut the costs of the first U.S. coal slurry pipeline
in Ohio. As their use has increased,the hopper car manufacturers
have gone from rotary-dump cars to bottom-dump cars with steeper
door chutes that allow full-car unloading in a few seconds.
Maintenence costs on unit train hopper cars are estimated at a-
bout 1.7C/tonne-km. Their life expectancy is not well docu-
mented because of basic changes in design (28).
It can be assumed that improvements in railroad technology
will continue, but one example of a step forward in train tech-
nology failed recently in Arizona (29). It was discovered that
concrete ties would not hold up to over-sized unit train oper-
ation and eventually failed. A 110-tonne car was used as opposed
to the normal 90-tonne car. Automation of the unit train was
also attempted. Because of an excessive number of flaws, the
automation system was disconnected and the unit train is now
operated manually. Similar systems had worked well in other lo-
cations but not on this larger scale.
Unit trains will be carrying most of the coal in the decades
ahead. The clear-cut advantages of unit trains can be summarized
briefly. In comparison to most other transportation modes,
trains need little water to operate, a factor especially impor-
tant in the western states. This is assuming that all locomo-
tives are diesel-electic and consume diesel fuel. if another oil
embargo of long-term duration occurs, making diesel fuel scarce,
coal-fired boilers could be used to power locomotives and water
18
-------
then would be required. This possibility is extremely remote.
Another advantage is that most of the track for unit train
haulage to electric utilities already exists, and the cost of the
trackage has been mostly absorbed by the railroads. Whether this
trackage is capable of handling intense unit train use is a
question that will be subsequently addressed. In addition, rail-
roads are relatively flexible and can expand or cut back service
easily with demand variations. It remains to be seen how extreme
an expansion can be handled by the nation's railroads.
The general assertions that trains are fast, dependable, and
energy conserving are somewhat difficult to substantiate. [Unit
trains move at 30 to 50 km/hr under load and nearly double these
speeds on the return empty haul.] Wasp (30) has provided some
data for a comparison of unit trains with slurry pipelines
(Table 9).
Railroads also have the advantage of offering more permanent
jobs than other modes, specifically pipelines and EHV lines from
mine-mouth power plants. This is a specious argument, however,
in light of most attempts by industry to reduce high labor costs
through automation.
The relative disadvantages of the use of railroads to trans-
port coal can also be briefly summarized. According to Wasp (30),
railroads have higher capital costs than slurry pipelines—as
much as 50% higher when original trackage does not exist. This
is due partially to railroad grade restrictions requiring 30% ex-
tra distance more than that necessary for a slurry pipeline. New
railroad construction costs vary from $500,000 to over $1,000,000
per mile, depending basically on the severity of the terrain
crossed (31).
Furthermore, railroad tariffs have a traditional sensitivity
to inflation—rail tariffs have increased at almost double the
rate of the national inflation rate. A recent statement from the
Council on Wage and Price Stability shows that with the latest
1977 rate increase of 5%, rail freight rates have escalated
106.7% since 1970. During the same period the implicit price de-
flator for total GNP increased by 55% and the consumer price in-
dex rose 56% (33). Historically, a tariff escalation rate of 3%
for railroads has been predicted (22), but in the year 1975-76
statistics pablished by the U.S. Bureau of Mines show an increase
of about 9.5% (34).. This is related to the high labor require-
ments of operating a railroad. In addition, the increased coal
traffic in the West may cause severe wear problems and deterior-
ation of grade ballast under increased traffic.
Some utility executives have spoken recently in favor of coal
slurry pipelines. Mr. F. Lewis, president of Middle South Utili-
ties, has stated, "Expressed in dollars, the annual movement of
19
-------
TABLE 9. COMPARISON OF REQUIREMENTS FOR 22.7x10 TONNES
ANNUAL COAL HAUL FROM WYOMING-ARKANSAS*
Item
Slurry pipeline
Unit train
Distance, km
Estimated life
Capital cost($106)
No. of unit trains
Locos/train
No. of cars
Freq. of operation
Personnel
Ste,el,tonnes/30 yr
Fuel equiv. for
Operation
Fuel cost
Inflation rate
Grade crossings
Coal loss; tonnes/yr
Water, m /yr
1670
30 yr
750
Continuous
335
409,090
1.3x10 tonnes
coal/yr
$5.6xl06
($4.40/tonne)
49 rail
nil
18.5xl06
(15,OOOAc-ft/yr)
2201
30 yr
730+
46
5
100
1800m train every
105 min, daily
2570
772,727*
409xl06 liters
diesel fuel/yr
$30xl06
(8$/liter)
5.4%
750 road
227,273
nil
*Source: Reference 30
Excludes upgrading of roadbed, assumes no abnormal track and
wheel wear, and neglects replacement costs of ties and ballast.
Galey (32) claims the capitalization, including 160 km of new
railroad would cost only $350 million. Furthermore, rail would
have an excess capacity of about 55 million tonnes annually over
the pipeline.
not include replacement of existing lighter rails with
heavy rail.
20
-------
25 million tons of coal (22.7 million tonnes) by slurry pipeline,
as compared to rail, would result in savings of approximately $14
billion over a 30-year period "(30). One 1500-megawatt power
station supplied by a coal slurry pipeline could save consumers
of electricity as much as $2 billion over a 40-year period, ac-
cording to G.W. Oprea, executive vice-president of Houston Light-
ing and Power Company (35).
When reliability of rail transportation was cited as an ad-
vantage earlier, the means of achieving it were not detailed.
At one unit train facility, (the previously-mentioned system in
Arizona (36)), reliability could only be guaranteed by redundant
equipment which undoubtedly increased the capital costs of the
system. It can be assumed that most railroads must follow this
practice to achieve a desired overall availability.
A secondary effect of coal haulage by rail centers around its
manpower requirements. If western coal production expands as
predicted, local populations are expected to expand with it. The
railroad's labor intensiveness could have severe growth implica-
tions on small western towns that will have already experienced
expansion due to the influx of mining personnel.
The environmental aspects of railroad haulage of coal also
must be considered. Conservation of fuel, especially from for-
eign oil sources, is important in the United States. Unit trains
use diesel fuel oil, which could become a scarce commodity. If
coal unit train traffic increases, the dependance on foreign oil
may increase also.
Conflicting land use is another aspect of railroads that
should be considered. The right-of-way width for railroads is
from 17m to 34m, which is similar to the right-of-way width for
coal slurry pipelines (25m). However, the land occupied by the
tracks and road bed are totally committed to rail transport
while the right-of-way occupied by a buried coal slurry pipeline
has contemporaneous land uses.
Noise pollution is a problem with unit trains. Sound levels
of from 88 to 98 decibels were recorded 15m from a diesel loco-
motive while noise from cars in tow measured from 80 to 94 deci-
bels at the same distance. According to one industrial safety
text (37), "although no definite level of sound intensity that
can cause hearing damage has been established, it is generally
accepted as on the order of 85 to 95 decibels." This text sug-
gested the wearing of ear protection for persons exposed to this
intensity of noise for extended periods. Some small towns in the
West have projected rail traffic of one unit train, one hundred
cars long, passing by every 20 minutes, night and day, 365 days
per year (38). There is hope, however, with the release of a new
Environmental Protection Agency (EPA) regulation limiting the
noise of diesel locomotives through the use of mufflers. The
21
-------
regulation takes effect in early 1980, but the EPA estimates that
it will take 25 years to replace the entire national locomotive
fleet with quieter models.
The vibrational damage to structures adjacent to the tracks
has yet to be studied, but it would be safe to assume that such
heavy coal traffic would have some adverse effect with the pas-
sage of time on structures relatively close to tracks.
Traffic disruption is a major problem with unit coal trains.
Fort Collins, Colorado, is bisected by railroad tracks. It cur-
rently experiences two unit coal trains per day, disrupting traf-
fic for a maximum of 5 minutes each time along the 18 grade
crossing on major streets. The number of trains is due to in-
crease to twelve daily within a year. It has been estimated (39)
that 11,000 automobiles will be idling each day, consuming about
3 million liters of gasoline per year. In addition, the trains
are disruptive to emergency services such as fire protection,
police, and ambulence operation. In Fort Collins the only hos-
pital and most of the fire stations are on the east side of the
tracks while the majority of residents they serve live on the
west side. This situation may force the duplication of services
on both sides of the tracks, an expensive endeavor for small and
large communities alike.
Rerouting the tracks around the affected community is an al-
ternative. At the present time this cost must be assumed by the
affected community. The town of Lusk, Wyoming, is in this exact
situation. In congressional testimony the following statement
was made: "The townspeople were told that the railroads would be
•happy to build a bypass to relieve Lusk of the damage and dislo-
catiori of heavy rail traffic - as long as Lusk paid for the new
right of way and all costs of relocating the line. Otherwise,
nothing would be done "(40).
Rerouting lessens but does not eliminate the problem of grade
-crossing related accidents. The rate of train-automobile acci-
dents is bound to increase as coal train traffic increases. When
railroads were compared to pipelines (petroleum) on a per tonne-
km basis from 1963 to 1968, the railroads had approximately 220
times more accidents than petroleum pipelines (30) . Railroads
had approximately 1700 fatalities per trillion tonne-km during
that time from all kinds of freight operations. The Federal
Railroad Administration (41) lists 910 fatalities from railroad-
highway crossing related accidents during 1975. The number in
1974 was 1221. The annual average over the past 10 years is
1444. There are 401,000 public and private grade crossings in
the country. In 1975 the total number of train accidents was
7895, representing a 5.4% increase over the previous year.
A bill was introduced in 1977 (42) to limit the length of
freight trains to 1310 m (about 75 cars) to improve safety and
22
-------
TABLE 10. RATIO OF EQUIPMENT FAILURES BASED ON TRAIN LENGTHS*
Failure
Burst air hoses
Sticking brakes
Coupler failure
Train delays
<75 cars
1
1
1
1
>75 cars
3
8.5
7.4
1.5
reliability by reducing derailments and equipment failure. Table
10 shows the relative increase in frequency o'f equipment failures
on long trains versus short trains. If long trains are made il-
legal, the manufacturers will not be able to make larger cars be-
cause of axle loading limitations.
An additional hazard associated with train operations is
fire. Sparks coming from locomotive emissions, hot boxes, brake
shoes, and maintenance crew operations can start fires along the
right-of-way in weeds, brush, and spilled coal. Rail operations
and lightning have been noted to be the two leading causes of
fire within Campbell and Converse Counties, Powder River basin,
Wyoming (30).
Environmental impacts on the railroad right-of-way are also
felt through the use of weed control agents. Railroads have
used chemicals such as 2-, 4-D, and 2-, 4-, 5-T for this purpose.
These agents are rated fourth on the USDA Toxicity Rating Chart.
Furthermore, coal is deposited along the right-of-way. It
has been estimated (43) that a unit train can lose 1% of its coal
on a haul of 1600 km. That represents approximately one car load
or 90 tonnes lost for each train unless a binder is used to con-
trol fugitive dust.
One problem common to many western coals is their suscepti-
bility to spontaneous combustion. Since railroads are labor in-
tensive, they are subject to occasional strikes. These two fac-
tors combine to become a potentially dangerous situation. A rail
strike would not have to last long, perhaps only a week, for any
loaded coal cars to ignite spontaneously. A coal-water slurry
pipeline has virtually no chance of experiencing spontaneous com-
bustion because of the lack of air and the high water content.
In short, these detrimental aspects of rail transport proba-
bly cannot be completely eliminated but should be minimized in
every available way. The fact that railroads are not presently
required to file any kind of environmental impact statement be-
fore their proposed increase of unit coal train traffic (44)
should be a point for future consideration and assessment.
23
-------
Mine-Mouth Power Generation and Extra-High Voltage Transmission
The use of mine-mouth power plants to generate electricity
and deliver it to consumers via transmission lines is another way
of moving the energy found in coal. Mine-mouth power plants are
numerous^ particularly in the Appalachian coal fields if there
exists a major river to supply cooling water and if other trans-
portation modes are difficult.
It would appear that moving electricity generated at the mine
mouth would amount to substantial savings, but it has been found
that Extra High Voltage Transmission (EHV) can be a more expen-
sive method of moving energy than either unit trains or coal slur-
ry pipelines (45) .
Environmental aspects of mine-mouth power generation must
also be considered. A power plant generally has an adverse en-
vironmental impact that adds to the impact of mining operations.
In addition to land use allocated to mining activities such as
preparation plants and mine refuse disposal, there must be added
land use for evaporation ponds or cooling towers, additional use
of water for cooling, and facilities for collection and disposal
°f_fly ash, bottom ash, and possibly scrubber sludge. Stack
emissions and cooling tower evaporation may have an adverse eff-
ect on the local atmospheric conditions and reduce the aesthetic
appeal the area may have.
Transmission lines and smokestacks can be dangerous to local
air traffic or may disrupt air traffic patterns. On the ground
transmission lines are aesthetically undesirable in rural set-
tings, and land use may require alteration.
Transmission line right-of-way is almost 200 meters wide com-
pared to 17 to 34 meters for railroads and 25 meters for coal
slurry pipelines. However, unlike the case of railroads, lands
traversed by transmission lines can support some land uses such
as agriculture with little acreage actually lost.
Deleterious health effects from electromagnetic fields near
EHV transmission are not fully understood.
Barge Transportation
About one-quarter of U.S. coal production moves by barge.
Barge transportation is obviously limited geographically to the
rivers and canals of the United States (Figure 3)(46). The ma-
jority of the inland waterways are found in the central and eas-
tern United States and barge transportation, therefore, is not
useful to deal directly with any western coal expansion. How-
ever, it is conceivable that a unit train unloading site or a
coal slurry pipeline terminus could be located on a major river
where the coal could be transferred to barges for waterway trans-
24
-------
to
en
LEGEND
I Anthracite and semianthracite
SI Low-volatile bituminous coal
0 Medium and high volatile bituminous coal
m Sub bituminous coal
ij Lignite
INLAND WATERWAYS
9 feet or more
v Under 9 feet
Proposed extensions
Under construction
Figure 3. Coal deposits in relation to inland waterways.(46)
-------
port to several consumers.
Barge transportation is the least expensive mode of coal
transport (Table 11). Although the costs are stated as 1972 dol-
lars, they provide a comparison of coal transportation costs.
Barge transport has historically been cheaper than rail
transport despite the additional miles created by circuitous
waterways. This may change in the future since unit trains move
more coal at faster speeds.
The disadvantages of barge transport include slow speed and
inflexible routing. In addition, special unloading facilities
are required, and loads are based on tow sizes which are limited
by chamber size of locks in navigable waterways while drafts of
barges are limited by controlling water channel depth. Though
some coal barges hold up to 1800 tonnes, the majority hold only
1300 tonnes. It appears that this transport mode will see lim-
ited growth as waterways become increasingly congested and pol-
luted. Growth in coal barge transport traffic on the Mississippi
River is expected to peak in 1980 (46), the greatest growth ex-
pected in the South as efforts are made to promote southern coal
exports to Japan.
River maintenance operations that must be performed by barge
companies presently do not amount to much as almost all the riv-
ers, locks, and dams as well as other navigational necessities
are maintained by the U.S. Army Corps of Engineers. This will
probably be the case for years to come, but the barge companies
may be subject to a river use tax in the near future that would
TABLE 11. COSTS OF COAL TRANSPORTATION(1972 ESTIMATES)*
Type
Unit train
Conventional
train
River barge
Slurry pipe-
line
Trucking
Conveyors
Costs , 2 Distance
(dollars per 10 assumed
BTU transported (km)
Fixed
5,100
9,240
4,850
48,500
1,850
10,500
Operating
79,800
145,000
35,600
20,800
16,700
5,100
Total
84,900
154,000
40,400
69,300
18,500
15,600
480
480
480
440
16
8
Cost,
cents/
tonne -km
0.5
0.9
0.2
0.4
3.1
5.2
*Source: Reference 47
26
-------
supposedly be used to improve and maintain the rivers and other
inland waterways of the United States.
The other major difficulty that barges must contend with is
the weather. On occasion barge traffic can be stopped due to ice
conditions for as long as several.weeks. Occasionally, drought
conditions can lower water levels, thereby necessitating a reduc-
tion in barge loadings.
Shiort Distance Transport Modes—Trucks and Conveyors
Truck transportation is a method of moving coal used when the
distance to be covered is quite small. Truck hauls of tens of
miles have been known, but were used only as short-term solutions
while more permanent answers were being sought to particular
transportation problems.
For the short haul trucks are flexible, but they have rela-
tively short equipment lives and require good roads, good weather
conditions, and skilled operators to function efficiently. It is
not economical to use trucks over long distances. Also, their
use might damage public highways with their increased loads.
For high-volume truck hauls, the overall work efficiency of
haulage is about 68-77% (48,49). Work efficiency of haulage does
not include maintenance downtime but does include time lost due
to queuing and refueling. The empty return haul is included as
operating time.
The maximum capacity of trucks for coal operations is 77
tonnes in the East and 155 tonnes in the West. Eastern coal min-
ing operations are more selective because of the thinner seams
while western operations must contend with much thicker seams.
Western trucks have unitized bodies of the tractor-trailer type
with over-size hoppers and bottom-dumping capabilities (48) .
Conveyor belt systems are also a short distance, high-volume
mode of transporting coal. Presently existing are lengths of up
to 30 km and widths to less than 2 meters. Aspects to be consid-
ered include the fact that some system components have short life
spans. The systems are usually above ground and aesthetically
undesirable, and they are exposed to the elements. Maintenance of
a mechanical coal transportation system is also critical.
While Table 11 shows truck transportation costs to be cheaper
than conveyors, another comparison shows the reverse (49) . It
was found that, based on a copper mining project, conveyors can
be more efficient energy users, less sensitive to inflation, and
less labor-intensive than trucks.
27
-------
Efficiency and Economics
A comparison of energy efficiencies of the various transpor-
tation modes is always open to question regarding assumptions
made. For instance, the author's own calculations for the Black
Mesa coal slurry pipeline show an energy requirement less than
one-half of that given in Table 12. Also, it is not known if the
truck and rail cases included an empty return haul.
The primary efficiency is the percentage of product lost
through wind and spillage. A slurry pipeline has no spillage in
normal operation, but its product does gain moisture. At Black
Mesa the mined coal has a moisture content of about 11% which in-
creased through slurry transport to 39% at the power plant boiler
after dewatering. Future improvements in the dewatering stage
are expected to reduce the final moisture content to 32% (17) .
Thus, the primary efficiency of 98% for the pipeline given in
Table 12 is much too high.
Though it is not the intention of this report to examine eco-
nomics in detail, it is probably fair to say that total transpor-
tation project costs must bear some relationship to environmental
impact. As project cost decreases, perhaps the environmental im-
pact does too. On that basis, it is interesting to compare the
transportation costs in a recent study by Banks and Leemans (50).
They compared the transportation of energy blocks of 1600, 3200,
6400, and 9000 MW increments over distances of 500, 900, and 1500
miles by rail, barge, pipeline, and transmission lines. They
concluded that the pipeline coal-energy transportation system in
11 of 12 cases was the most economical means of transporting en1-
ergy. Except for large energy blocks at long distances, rail-
barge transportation systems, as defined in the study, were the
second most attractive alternate. Railroads, in half of the
cases studied, proved to be the most expensive means of trans-
porting energy.
Pneumatic Pipelines^
The transportation of coal over long distances by pneumatic
pipeline is generally agreed to be uneconomical at present, but
it may be a viable alternative in the future (51,52,53,54,55).
From a technical and economical point of view, water is pre-
sently the most desirable lubricant or carrier for the pipeline
transport of coal. However, if western coal and western water
are considered incompatible, the temptation to utilize air as a
carrier vehicle is very strong.
Air is free for the taking and poses no de-watering problem.
However, the pneumatic pipeline transportation of coal is neither
technically nor economically feasible for long distances with
present-day technology. Air does not have adequate viscosity and
28
-------
TABLE 12. COAL TRANSPORTATION ENERGY EFFICIENCIES*
to
Method
and
Location
Unit trains
Northwest
Central
Northern Appalachian
Central Appalachian
Southwest
Mixed or conventional train
Northwest
Central
Northern Appalachian
Central Appalachian
River barge
Central
Northern Appalachian
Central Appalachian
Trucking
Northwest
Central
Northern Appalachian
Central Appalachian
Conveyor
Central
Northern Appalachian
Central Appalachian
Slurry pipeline
Primary Ancillary energy
efficiency requirement
(percent) (109 BTU's per 1012 BTU's
transported
99
9.9
15.8
15.8
18.7
5.89
98
7.82
12.5
12.6
10.7
98
8.9
21.3
7.76
99
1.27
. 1.07
0.96
0.93
99
0.42
0.37
0.38
98 7.09
Average haul
distance
(km)
241
467
515
636
161
241
467
467
443
483
1287
483
16
16
16
16
8
8
8
439
*Source:
-------
density to support coal particles in suspension to the same de-
gree as water does, even when the coal is pulverized. Low pres-
sures, high velocities and hence large air flows are necessary to
keep the coal in suspension. This is called dilute-phase (low
solids concentration) flow. For pulverized coal the velocity can
be reduced, but the pressure drop increases. This is called
dense-phase (high solids concentration) flow. Both types of flow
regimes consume large amounts of energy in conveying the coal in
addition to the cost of collecting and compressing the air.
For instance, the author has shown elsewhere (53) that for
coarse aggregate the specific power (kw-hr/tonne-km) for slurry
transport is about one-tenth that for dilute-phase pneumatic
transport by pipeline. Presumably coarse coal would give a simi-
lar comparison.
Also, coal feeders and air blowers or compressors are not
presently available in the sizes necessary for the high through-
puts envisioned for overland transport by pipeline. Existing
pneumatic pipelines seldom extend for more than 300 meters and
typically transport less then several hundred tonnes per hour.
Proposed coal slurry pipelines are expected to traverse a thou-
sand miles overland and to carry several thousands of tonnes of
coal per hour.
The safety of transporting coal pneumatically by pipeline
has been questioned. The U.S. Bureau of Mines has been trying to
establish a guideline for permitting pneumatic pipelines in un-
derground coal mines. None exists in the United States to the
author's knowledge, but several are working in the United King-
dom (5,2,56). The higher methane levels in eastern U.S. Mines are
offered as a reason for possible methane gas explosions in pneu-
matic pipelines. Although unproven, it has been hypothesized
that a coal pneumatic pipeline leaking coal dust less than 0.8mm
in size in a local concentration of 80 grams per cubic meter next
to an ignition source could cause an explosion (57) . A recent
U.S. Bureau of Mines publication (58) suggests that combinations
of coal dust and methane are explosive mixtures but are unlikely
to be ignited by tramp rock of metal flowing in a pipeline.
Having considered some of the effects of the alternate
coal transportation modes, this writer will now examine the en-
vironmental aspects of slurry pipelines.
30
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SECTION 3
WATER QUANTITY AND QUALITY
Water is the Achilla's heel of a slurry pipeline. Without
it, there is no slurry pipeline. Although water is our most a-
bundant resource, it is not always found where it is needed. In
a sense water is akin to energy because it is neither created nor
detroyed but transformed between its three phases: solid, liq-
uid, and gas. The hydrologic cycle of precipitation, runoff, in-
filtration, transpiration, and evaporation—demonstrates this
principle of transformation.
Because water is our most essential human requirement, it
becomes a controversial issue whether the application is recre-
ation, hydroelectric power, irrigation, or energy transportation
by pipeline. The quest for domestic energy independence by sub-
stituting coal for oil and gas will require water. Whether coal
is burned directly in power plants or converted to gas, liquid, or
upgraded solid fuel, vast quantities of water will be required.
Coal slurry pipelines are a proven technology and are a com-
petitive mode of transportation for moving coal. Its carrier
liquid should be abundant and inexpensive, and its use should en-
tail minimum adverse environmental impact. From a technical and
economical viewpoint, water is presently the most desirable lub-
ricant for the pipeline transportation of coal. It is the most
readily available fluid even in the semi-arid West. Hydrocarbon
carriers such as oil have not been found in economical quantities
near a source of coal. A heavy gas such as pressurized carbon
dioxide is expensive to collect and compress and does not support
coal particles in suspension for economical transport by pipeline
to the same extent as water. Methanol derived from coal looks
promising as a coal carrier, but many technical and economical
questions must be answered before this transportation mode be-
comes viable. Hydrocarbon carriers are discussed in more detail
in Section 7.
This section examines the amount of water required for a
coal-water slurry system and comments on the quality of available
water.
31
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WATER QUANTITY
The quantity of water necessary for a coal slurry is deter-
mined from two factor's: annual throughput (usually expressed in
million tonnes) and solids concentration. The concentration by
weight of coal is Cw, the weight ratio of dry coal to that of
slurry (dry coal+water).
Long-distance coal slurry pipelines have transported coal
concentrations from 40% to 60% by weight, usually averaging just
under 50%. For convenience in further calculations, 0^=50% will
be assumed, giving the following simple relationship: 1 tonne of
coal requires 1 tonne of water to produce a coal-water slurry.
Table 13 lists various relationships for the amount of water re-
quired based upon a 50% weight concentration. These requirements
are applicable to any coal regardless of its calorific value.
When comparisons are drawn between water requirements for alter-
nate energy transportation modes, the heat content must be con-
sidered for an unbiased assessment of the different requirements.
The higher the water requirements are for a particular energy
system, the more environmentally upsetting that system is. Table
14 summarizes the water requirements of various transportation
modes (59) .
A small amount of additional water would be required by the
pump stations in a slurry pipeline system for cooling transmis-
sions and motors and as a flushing medium to keep solids in the
slurry from scoring the shaft, piston rods, or plungers in the
pumps.
Positive displacement (PD) pumps have been used to pump coal
slurries over long distances. Though they are low-flow capacity
pumps, they develop high pressures suitable for long-distance
pumping. To obtain high flow rates, PD pumps are placed in par-
allel.
The Black Mesa pump stations use typically 1.6 1/s of water
from their storage pond for evaporation, pond seepage, and cool-
ing. In warm weather approximately 80% (1.25 1/s) is lost to
evaporation. Thus, the maximum water requirement per pump sta-
tion represents about 1/2% of the total slurry flow (or about 1%
of the water carrier flow).
The pipeline operation requires 3.95x10 m of water per year.
Flagstaff, the city closest to Black Mesa, uses about 8.63xl06m3
per'year. These consumptions are insignificant compared to the
evaporation loss (estimated at 802xl06m3 per year) from Lake Pow-
ell on the Arizona-Utah border.
The piston pumps at Black Mesa use recirculating flush li-
quids consisting of soluble oil and water or diesel oil and water.
32
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TABLE 13. WATER REQUIREMENTS FOR 50% BY WEIGHT COAL SLURRY
Coal Water
1 kg 1 kg
1 tonne 1 tonne
1 Ib 1 Ib
5xl06 ton/yr 3,678 Ac-ft/yr=4,536,813 m3/yr
15x10^ ton/yr 11,033 Ac-ft/yr
25xl06 ton/yr 18,389 Ac-ft/yr
1 ton/hr 3.994gpm=0.008993 cfs=5812 gal/day
1 tonne/hr 0.0002778 m3/s, 0.27783 1/s
5xl06 tonne/yr 5x106 m3/yr
TABLE 14. WATER REQUIREMENTS OF VARIOUS ENERGY
TRANSPORTATION ALTERNATIVES*
Alternatives
Gasification
Liquifaction
Mine Mouth Power
Plant (Wet Cooling Towers)
Unit Trains
Barges
Trucks
Conveyor Belts
Pneumatic Pipelines
Slurry Pipelines (C^=53%)
Water
m /joule
26 to 57
11 to 72
305
nil
nil
nil
nil
nil
38
Requirements
Tonnes Water
Tonnes Coal
0.6 to 1.32
0.26 to 1.66
8.0
nil
nil
nil
nil
nil
0.89
*Source: Reference 59
Data assumes a heat value of coal of 10,000 BTU/lb.
(23,250 Joules/gram)
33
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Approximately 114 liters are used in a closed circulating system
to flush the pump glands.
Water Resources
America is said to be one of the few countries with relative-
ly abundant water supplies. However, in light of recent problems
involving the use and pollution of our water resources, Americans
now realize that water is a very precious commodity and must be
used wisely. A high standard of life is a prized possession to
all Americans.
Energy production is the common bond between these two enti-
ties: water and living standards. Water is a primary necessity
for life, yet it is also necessary for the continuance of heavy
industry. Amounts of water allotted to industrial, agricultural,
municipal consumers must be balanced. It is easy to assume that
agricultural and municipal use takes precedent over industrial
use, but farms and municipalities could not function without the
heavy equipment and power provided by industry. Figure 4 illu-
strates the various water uses in the United States.
In some states agriculture utilizes the lion's share of water
but contributes a smaller percentage of revenue to the state than
industrial sources*; In Colorado, for example, 1976 statistics
indicate that agriculture contributed approximately 6 billion
dollars in cash receipts to the total of approximately 21 billion
dollars of gross state revenues and employed almost 17% of the
state's labor force. However, agriculture consumes 92% of the to-
tal water in the state (61,62). Viewed in this way, therefore,
•the role of water—its worth and priorities—may have to be re-
evaluated in the near future, especially if a state chooses to
increase energy production at the expense of agriculture. In or-
der to balance water usage between industry and agriculture, it
will be necessary to attach more importance to water conservation.
For example, irrigation systems incur tremendous losses to eva-
poration and seepage. Figure 5 shows the relative amounts that
are lost and used for irrigation. The water saved by improved
irrigation practices and ditch lining could be utilized by energy
producing or energy transportation industries. The laws govern-
ing water allocation may have to be changed to benefit all users:
industrial, agricultural, and municipal. Water allocation laws
vary from state to state. Perhaps a uniform set of water alloca-
tion laws is needed in the western states to assure the proper
development of energy resources without detrimental effects on
other users of water.
Groundwater
Water covers 75% of the total surface area of the earth. It
is found in oceans, rivers, lakes, polar ice caps, and under-
ground in the form of aquifers.
34
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Figure 4. The many uses of water in the U.S.A.(60)
35
-------
•
I i rai
rainfall
5.3
deli vered
to farms
4.9 \
conveyance and
regulation waste
6.0
received
4.4
absorbed
by sot/
surface
runoff
]
0.4
water
evaporation
1^6 u&ed by crops \
6 deep
{ percolation
fest.l
Figure 5. Disposal of water diverted and pumped for irrigation
(relative values).(60)
An aquifer is a p0rous;water-bearing rock formation whose
pores are connected so that the formation is considered permeable.
The ability for water to flow through these pores is called
transmissivity. The water-bearing aquifer can be shallow or deep
beneath the earth's surface. The water can be obtained from
springs if the aquifer is shallow and topographic conditions per-
mit. If the aquifer does not intercept the surface, water can be
obtained through wells drilled to the aquifer. Sometimes local
pressures allow the water to flow out of wells, but most often
the water must be pumped to the surface. The principal aquifers
of the United States are illustrated in Figure 6.
An aquifer very much in the spotlight at present is the Madi-
son limestone formation that underlies the Powder River Basin in
Wyoming and parts of Montana, and South Dakota. Energy Transpor-
tation Systems, Inc. (ETSI) plans to use water from this aquifer
(48.7x10° hectares) for their coal slurry pipeline to Arkansas.
The hydrological implications of this project are immense (63).
Many reports have been written about the Madison aquifer and in-
dicate various opinions about the amount of the impact that the
removal of water from the Madison will have on groundwater supply
of the Northern Great Plains.
The following quote from a USGS map of various Madison geo-
logical features illustrates recent use of water from the Madi-
son (64) :
According to the Wyoming State Engineer(1974)
about 30.8 million m^ of water was withdrawn from the
Madison in the Wyoming part of the Powder River Basin
in 1973. The Madison is the principal source of water
for secondary recovery of oil in the Powder River Basin
in Wyoming. More than 24.7 million m^ was used for se-
36
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u>
nBoir. u
Co«»i,
a No' hoowA TO DC undC'iQi^ Oy
01 muchot 50 ooi/f^p" 'o >-e«i
Figure 6. Major aquifers in the U.S. (60)
-------
condary recovery of oil and about 3.7 million m3 was
used for municipal water supplies. Other water use
from the Madison includes about 1.2 million m3 per
year in the Osage-Newcastle area for electric power
generation and for oil refinery water requirements.
A major problem is predicting the behavior of an extensive
aquifer when it is stressed by the removal of 18.5 million m3 of
water per year as proposed by ETSI.
The USGS is attempting to address these problems in a study
of the Madison formation. At the time of this writing, the study
is in the second year of the five years expected for completion.
The study does not necessarily deal with the requirements for a
slurry pipeline. Rather, it deals with water quantity and qual-
ity in the Powder River Basin without regard to who will actually
use the water and how.
The study has the following objectives: (63)
1. To determine the quantity of water that may be available from
the Madison aquifer.
2. To define the chemical and physical properties of the water.
3. To determine the effects of existing developments on the po-
tentiometric head, the storage, the recharge and discharge,
the springs, the streamflow, and the pattern of ground-water
flow.
4. To predict the probable hydrologic effects of proposed with-
drawals of water for large-scale developments at selected
rates and locations.
5. To determine the locations of wells and the type of construc-
tion and development of deep wells that would obtain optimum
yields.
6. To design a network of observation wells and stream gages to
monitor the effects of additional developments of the hydro-
logic system.
According to Elliot Gushing, the engineer in charge of the
project, the primary goal is to define adequately the Madison
with a computer model to predict accurately the results of pump-
ing for a number of years. The USGS is attempting to find the
best area in the basin to drill wells. The selection of this
area is a function of many factors but is primarily concerned
with the depth of the formation and with predicted yield rates.
A computer model of the Madison aquifer was formulated (65),
using the existing scarce data available before actual planning
of drill sites and gathering of additional data, which will take
place during the five years planned for the study. The purpose
of this model was to aid in gathering data to show where critical
information was lacking. Remembering that a computer model is
only as accurate as its input data, many assumptions were re-
38
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quired to formulate the model, and it will be these assumptions
that will be checked in the data collection. As more data are
collected, the accuracy of the model will be improved.
Mr. Gushing notes that every energy development project re-
quiring water need not go into as,much detail as the USGS has in
the case of the Madison aquifer. The reason for the modeling of
the Powder River Basin stems from the basin's sheer vastness,
posing a complex problem of understanding interrelated variables.
To satisfy most State agencies the hydrology of the water
source must be known, including information about objectives out-
lined by the geological survey. The time and cost of such an en-
deavor would probably vary directly with the extent and complex-
ity of the aquifer studied. The cost of the USGS 5-year plan was
estimated at 11.4 million dollars for this area of about 49 mil-
lion hectares (63) .
The amount or capacity of water that a particular aquifer
can hold is generally finite; and if the extensive hydrological
studies suggested previously are performed, this capacity is
roughly calculable While removal of water from an aquifer gen-
erally lowers the water table in the vicinity of the well in
what is called the drawdown cone, the aquifer will not necessar-
ily be drained dry.
Most aquifers intersect the surface at some point and re-
ceive surface water in the form of runoff or snow melt in the
spring. The recharge of the aquifer with new water is generally
a continuous process. However, if the rate of removal of water
from the aquifer is greater than the recharge rate, groundwater
mining results, and the aquifer could dry up and the water table
could be permanently lowered.
The water permits granted to ETSI by the State of ^yoming
have the following stipulations: (66)
If the permittee lowers the water table, the permittee
has the choice of:
1) Deepening the wells and paying for damages which
may include extra cost of water for farmers,
2) Supplying water to people whose water supply was
decreased when the water table was lowered,
3) Obtaining its water elsewhere.
The permittee will pay the costs of court and reasonable
fees of attorneys and experts of any person who is re-
quired to enforce the terms of this permit by legal ac-
tion, provided said person is successful in obtaining a
final judgement in his favor and against the permittee.
The permit may be terminated by the state engineer if
39
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the water table is endangered. This decision can be
contested in court.
In 1971 the U.S. Geological Survey initiated a groundwater
monitoring project to determine the magnitude of declines that
can be attributed solely to the pumpage from the Peabody well
field at Black Mesa. Four observation wells were drilled in 1972
and another was available in the community of Kayenta. By Jan-
uary 1977 two wells showed no change, two showed a decline of a-
bout two meters, and.the fifth (in Kayenta) showed a steady de-
cline since 1967. Most of the decline, however, is probably
caused by the increase in municipal pumpage required to support
an increasing population. The data are not considered conclusive
evidence about water quantity. No changes in water quality have
been detected to date (67) .
An aquifer could be artificially recharged by drilling down
to the aquifer and injecting surface water to replace water re-
moved elsewhere in the aquifer. A pipeline firm could pump water
from an aquifer at one point while at another it could inject
water into the same aquifer from a flood-swollen river on the
surface. It would lessen the possibility of groundwater mining
and could supply the slurry water requirements at a different lo-
cation without the necessity of building overland pipelines to
the origin of the slurry pipeline. Obviously, the groundwater
profile must be defined completely before this type of flow ex-
change can be implemented.
Another source of underground water might possibly be mine
wastewater, which is generally acidic. The removal of this water
from an area would benefit any local water shed. The application
of this idea is not generally practised because the presence of
this type of water source is usually localized. Nevertheless, if
conditions permit, the use of this source of water should be con-
sidered. It does, however, present other problems.
Water Rights
The procedure for obtaining water rights in the West is
quite rigorous. For example, in Colorado, water rights are de-
termined by meeting several burdens. These burdens are designed
to assure that water appropriation and use will help to maximize
the beneficial use of all the waters of the state in accordance
with the well established principles of the appropriation doc-
trine:
(i) Waters of the state are the property of the public,
dedicated to the use of the people of the state;
(ii) The right to divert the unappropriated waters of
any natural stream to beneficial uses shall never
be denied;
(iii) Priority of appropriation shall give the better
right as between those using water for the same
40
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purpose—first in time is first in right.
Wisely, the doctrine does not establish a priority list of
water use. The third and first principles allow for re-alloca-
tion of water to energy production and transportation once people
are convinced it is to their benefit to do so. Once the transfer
of water rights from agriculture to the energy industry looks
feasible, it is the onus of the energy industry to define the en-
vironmental impact of their proposed project. A water rights ap-
plicant must negotiate a rigorous obstacle course marked along
the way by challenges from numerous adversaries, both public and
private. Therefore, it is not surprising that water for a coal
slurry pipeline is sought from groundwater sources, which are more
apt to be unappropriated and non-tributary to other surface or
underground water rights.
Surface Water Sources
Since surface water is visible, it does not present the
same degree of difficulty as groundwater when defining its quan-
tity and quality. Furthermore, most surface waters are already
allocated to agriculture, industry, and municipal users.
Surface water is much cheaper to utilize than underground
water sources. It is obvious that the costs of drilling deep
wells to aquifers and pumping the water to the surface are much
higher that diverting a stream or river into an irrigation ditch
or piping water a short distance from a reservoir. Therefore,
the use of surface water for coal slurry pipelines should be con-
sidered before proceeding to drilling programs that tap aquifers.
The principal source of surface water is precipitation. Water
in the form of runoff not absorbed by the soil, evaporated, and
utilized by plant life flows into streams which may feed rivers
or lakes in a watershed. Water is used and reused many times on
its journey to the sea in rivers. When runoff is excessive, such
as in the case of the entire Mississippi watershed almost every
spring, it could be diverted to other beneficial uses, at the
same time minimizing the possibilities of downstream flooding.
Diversion of water from flood control dams to coal slurry pipe-
lines would constitute a beneficial use. Since a drought could
occur at any time the use of surface water for coal slurry at
such times might conflict with higher priority usage. Therefore,
both surface and groundwater supplies may be desirable for a coal
slurry pipeline to ensure water availability during the life of
the project.
Other possibilities should also be investigated: first, the
utilization of municipal or industrial waste water after primary
or secondary treatment; second, the prospects of joint use of
water supply pipelines with municipalities; third, the use of
contaminated mine water; and fourth, the use of brine or salt
water. The use of these alternatives involves additional envir-
41
-------
onmental and engineering considerations which will be discussed
subsequently.
Recycling or recirculation of the water carrier has been
suggested as a means of conserving water. This involves taking
the water from the separation plant and'—instead of sending it as
cooling water to the power plant—transporting it by pipeline
back to the preparation plant at the head of the pipeline.
Odasz (68) of ETSI claims that the annual 18.5 million m3 of
water required for the Wyoming-Arkansas coal slurry pipeline
could have been purchased from the Oahe Reservoir for $0.97/mJ,
or that a recycle line could have been built from Arkansas to
Wyoming at a cost of $2.84/m3 for the water returned. In addi-
tion, the recycle line would need 267,000 tonnes of steel and a
continuous power consumption of 39,000 kw to return the water up-
hill. Neither of these alternatives is attractive since the cost
of water from the wellfield is estimated at $0.32/m3. The cost
of recycling water would be prohibitive, and the slurry pipeline
would not be economically competitive. The material required to
build the return line and the energy needed to return the water
would not be environmentally advantageous from the viewpoint of
total conservation of resources.
The economic advantage of a slurry pipeline results from
high throughput over long distances with a high use factor. Any-
thing disruptive of these three aspects weakens the economic ad-
vantage. Since the cost of steel pipe comprises a substantial
portion of the total cost of the project, any additional pipe
length also weakens the economic advantage.
WATER QUALITY
After considering the possible water sources for a coal
slurry pipeline, the quality of water from those sources should
also be examined. The maintenance or improvement of the original
water quality after its use should be the goal of any pipeline
operator.
There are four groups of variables that help to define the
quality of water: 1) physical, 2) chemical, 3) microbio-
logical, and 4) radiological characteristics. The variables in-
clude: taste, odor, color, turbidity, temperature, dissolved ox-
ygen, chemical oxygen demand, pH, dissolved organic and inorganic
chemicals including pesticides, dissolved and suspended solids,
biological oxygen demand, total oxygen demand (the sum of bio-
logical and chemical oxygen demands), coliform organisms, fecal
coliforms, and the various types of residual radioactivity. Some
of these variables overlap with other variables—for example,
when color, turbidity, and total oxygen demand are combined.
42
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The U.S. Department of Health has standards for public
drinking water that define exactly the amounts of the above var-
iables that are allowable or desirable (see Appendix B) .
By comparing the quality of water to be used in a slurry
pipeline to the water quality standards for other uses, the al-
ternate uses of the water source in question can be determined.
This comparison is important because the development of a partic-
ular geographical area may hinge on the availability of water for
certain types of consumption. If a source of unallocated water
is high quality according to the public health standards for
drinking water, it should be retained for a domestic water supply
first. This would encourage population growth in any municipal-
ity with access to the supply. On the other hand, the water
quality may be poor so that it can be used only for agricultural
consumption—irrigation or livestock watering. If a new water
supply can be treated at some cost to bring the quality into the
range of municipal use, a community may want to limit its growth
potential as an industrial town but encourage its growth potent-
ial as an agricultural community. The difference between agri-
culture and industry could hinge on water quality. There are, of
course,, other factors that would affect such a decision, but
these are beyond the scope of this report.
Ideally, the water proposed for a slurry pipeline should
have few alternate uses. For example, a high amount of dis-
solved solids may make water unfit even for irrigation. An a-
mount of total inorganic dissolved solids above 500 ing/liter
makes water unfit for watering livestock (Appendix B) . Further-
more, water having from 1000 to 2000 mg/liter of dissolved solids
may produce adverse effects on many crops unless careful agricul-
tural management practices are followed (60). It should be noted
that some municipalities in the West drink water that is suppos-
edly unfit for livestock consumption (40) .
Before any alternate uses for a water source can be deter-
mined, a series of water quality tests should be performed. The
water quality variables that would most concern the operator of a
slurry pipeline are those that may affect the flow and corrosive
properties of the slurry and the combustion of the coal. These
are dissolved oxygen, pH, trace chemical constituents, and dis-
solved and suspended solids. Treatment of the separated water
for cooling at the power plant is required regardless of the in-
itial quality of the water in the slurry. A method for separ-
ating and identifying the six groups of organic compounds has
been developed by Leenheer (69). This method, which takes_two
days and requires a 200 ml sample, involves the fractionation or
separation of the organic constituents found in a particular
water sample. Using this method and standard water quality tests
for inorganic compounds, the determination can be made of any
water quality change after transport with coal. Concentrations
of trace inorganic substances then can be compared to a tabuia-
43
-------
lation formulized by Gough and Shacklette (70), and the effect
of the trace elements on water quality can be assessed.
In the slurry pipeline projects under consideration, there
would be no discharge of slurry water into local watersheds. For
example, the Mohave Plant in Nevada is served solely by a coal
slurry pipeline and observes this practice. The entire liquid
component of the slurry—minus whatever moisture that remains on
the coal—is used for condenser cooling water, which constitutes
about 11% of the amount necessary at the power plant (9). How-
ever, the water remaining from the slurry dewatering should be
analyzed to determine its possible alternate uses and if it could
be safely discharged into adjacent watersheds. In other words,
water quality should .be monitored both before and after slurry
transport to determine any changes.
The quality of water has other effects on engineering para-
meters associated with the operation of a slurry pipeline system.
The effects of low-quality water should be examined both from a
total environmental and engineering viewpoint (44):
Coal slurry pipelines can use a variety of waste
water. Sewage water, steam condensate, rain or snow
runoff, brines and even ocean water might be used to
make up the slurry. It is doubtful if any urban area
would object if the mine operator volunteered to ac-
cept the pretreated sewage of the entire municipality.
Such water would not detract from the thermal or ig-
nition qualities of the coal. The slurrying of coal
and waste water would in many cases provide "primary
treatment" advantages to both.
Coal grains, washed and tumbled in settled sewer
water are leached of some of the soluble minerals and
colatile acids, and the ash content of the coal is re-
duced. Sewer water is essentially detoxified by per-
colating through coal; most bacteria are analysed and
many cations and anions are precipitated. Surfactents,
proteinaceous and fatty acid materials are inactivated
or bound to the coal material. The coal and all the
solids or semi-solid organic material which adheres to
it are readily burned with a gain in BTU content. The
waste water is essentially purified with its contact
with the coal and simple centrifugation and pH adjust-
ment will usually render the water suitable for other
uses.
Simply put, the coal in the slurry may act like activated char-
coal adsorbing some of the harmful constituents of the water
during transportation. It is reasonable to assume that the finer
the coal particles, the better the adsorption will be because of
the increased surface area available.
44
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There is also the possibility that the chemicals adsorbed
onto the coal particles may go up the stack when the coal is
burned. This point has not been proven either way, but it may be
that trace elements or compounds are left behind with the bottom
ash.
Buck (44) contends that halides in saline water are easily
vaporized in the combustion chamber. In essence, a water quality
problem, then, is changed to an air quality problem. In addition,
the ash content of the coal would be increased from the metallic
ions of magnesium, manganese, and sodium.
A substantial amount of saline groundwater is said to under-
lie the western states as a result of residues from ancient geo-
logical periods when the area was covered with salt water seas.
Table 15 classifies saline water according to total dissolved
solids.
Evans and Rice (10) have considered the use of saline water
for coal slurry pipelines and have made the following observa-
tions:
1. Saline water in the West exists at depths of from 150 to
300 meters.
2. The Madison aquifer contains water with salinity averaging
between 1000 and 3000 mg/1. Salinity constituents are pri-
marily sodium bicarbonates and sodium chlorides in the
eastern half of the Madison and sodium and calcium sulfates
in the western half of the formation.
3. Saline groundwater cannot be pumped from the western states
indiscriminately and indefinitely. It is possible in the
western states to find saline aquifers overlain by fresh
water aquifers that are not hydrologically isolated from
each other. Pumping of the saline strata might cause flow
changes in the fresh water aquifer or even intrusion of the
fresh water into the salt water. Other possible environ-
mental consequences of salt water pumping include land sub-
sidence similar to that caused by oil and gas withdrawal
and contamination of moderately saline groundwater with
more highly saline water from deeper aquifers.
4. If saline groundwater is used as a coal carrier, the cor-
rosivity of the slurry would increase and corrosion inhib-
TABLE 15. CLASSIFICATIONS OF SALINE WATER
Total Dissolved Solids Concentration,ppm
Fresh 0-1,000
Brackish 1,000-10,000
Salty 10,000-100,000
Brine >100,000
45
-------
itors would be required (antioxidants, or pH adjustment).
5. A hypothetical case is examined where a large coal slurry
pipeline ruptures and spills a saline coal slurry. En-
vironmental damage is considered to be of little conse-
quence because of dilution.
6. Soluble salts in coal are expected to leach into the water
carrier whether it is saline or fresh. However, western
coals have a negligible chlorine content and are not ex-
pected to produce significant leaching.
7. Saline water would add an evaporated residue to the ash
and sludge waste load of the power plant.
8. In summary, Evans and Rice (10) make the following
statement:
... it would appear that one of the chief environ-
mental impacts of coal slurry pipeline operations-con-
sumptive use of potable water in the western coal re-
source areas - can be substantially reduced by the use
of saline groundwater without introducing any signifi-
cant problems along the pipeline.
Recent studies by Sanguanruang and Moore (71,72) examined
the water quality aspects of coal slurries. Two different coals
from Wyoming were slurried in three concentrations of distilled
water and treated wastewater. After filtration the effluent was
tested for water quality changes in a dozen categories. It was
concluded that generally the concentration of contaminants in
slurry wastewater are increased because of contact with the coal.
The major increases were in total dissolved solids, total hard-
,ness, sulfate, magnesium, and sodium. Slurry transportation by
pipeline is not necessarily a beneficial coal-washing technique.
The increases in contaminants in the slurry water are measured in
mg/1 and are still insignificant compared to the total weight of
contaminants. For example, sulfate and organic sulfur in the
slurry water are increased, but overall sulfur reduction in the
coal is negligible.
In a telecon with Prof. Moore, he expressed the opinion that
a coal slurry would probably not behave totally like an activated
charcoal filter because some of the contaminants were a result of
physical processes and others a result of chemical processes.
Though saline water was not tested, the high level of chlorides
in some coals combined with high chloride levels in some water
carriers (e.g.) seawater contains ~ 35,000 mg/1 chloride leads
Prof. Moore to speculate that seawater or saline water with high
chloride levels would not be acceptable as slurry water pipe-
lined to power plants.
Since the coal would not be dewatered completely, a high
chloride content would result in wet scrubber corrosion. Thermal
drying could reduce the moisture content substantially but would
not remove the chloride. The new environmental regulation re-
46
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quiring wet scrubbers for flue gas desulfurization increases the
potential of chloride corrosion. While corrosion is a common
problem in power plants, it is unlikely that the corrosion level
caused by coal high in chlorides could be tolerated.
Treated wastewater would not.be expected to be high in
chlorides if the raw water source were not high in chlorides.
Treated wastewaters with a high chloride content, although less
frequently encountered, would not be desirable.
47
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SECTION 4
DEWATERING
Dewatering is the final operation in a slurry pipeline sys-
tem. Before any environmental effects of dewatering can be dis-
cussed, the dewatering activities should be examined.
Conventional components of coal slurry dewatering systems
include the following:
1. Centrifugation
a) solid bowl
b) screen bowl
2. Vacuum Filtration
a) disc
b) horizontal belt
3. Thermal Drying
a) flash dryer
b) fluid bed dryer
c) rotary dryer
These components cannot be discussed in .detail here because
of their wide range of application. However, components which
have been used in the terminals of two long-distance coal slurry
pipelines will be discussed. These pipelines are the Cadiz-East-
lake line in Ohio (no longer operating) and the operating Black
Mesa line in Arizona. The major operating characteristics of
these two pipelines and their respective dewatering systems are
listed in Table 16.
Because the Cadiz-Eastlake line was the first coal slurry
pipeline, its dewatering system (Figure 7) contained a number of
components found to be unnecessary after its initial startup in
1957. Though not shown in the flow diagram, the slurry was dis-
charged into thickeners prior to entering the vacuum disc filters.
The^thickeners proved to be unnecessary.
The dewatering facility at the Eastlake Power Plant com-
prised three major components, each with its own special opera-
tional difficulty. The first was the vacuum disc filter. Init-
ial wear problems necessitated the replacing of the plastic woven
48
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TABLE 16: CHARACTERISTICS OF CADIZ-EASTLAKE PIPELINE IN OHIO
AND BLACK MESA PIPELINE IN ARIZONA*
Characteristic
Cadiz-Eastlake
(1957-1963)
Black Mesa
(1970
Length
Diameter
Throughput(MTPY)
Coal moisture(%)
Coal sp.gravity
Coal heat value
Percent solids by weight
Particle size
Capacity range
Main separator
Clariflocculator use
Desired boiler
coal feed moisture
174 km
254 mm
1.36
2.0
1.352
12,000 BTU/lb.
50 to 60
43 ym (20%)
118 to 182 TPH
Disc filters
Yes
9%
Actual coal feed moisture(%) 7%
Thermal heating method
Slurry heating
Flash dryers
burning coal
No
439 km
457 mm
4.36
10.74
1.45
12,300 BTU/lb.
46 to 48
43 ym (20%)
509 to 600 TPH
Solid bowl
centrifuges
Yes
25%
32%
Primary air and
gas burners
Yes
*Source: References 17, 73, and 74.
49
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PIPELINE
2-HOUR
SURGE TANK
CLARIFLOCCULATOR
VACUUM
DISC
FILTER
^ FILTER CAKE
18-20% SURFACE MOISTURE
-~82"C
WET
SCRUBBER
BY-PASSED CAKE
AA
RAIL COAL
BUNKER SYSTEM
4-25 PPM
POWER PLANT
STACK
Figure 7. Flow diagram: Eastlake pipeline coal utilization (74)
-------
cloth with a wear-resistant stainless steel cloth. The second
was the flash drier with its associated drying column cyclone and
wet scrubber. The flash drier was operated on pulverized coal
and consumed approximately 3% of the coal entering the plant (74)
The problem initially with the flash drier was that it produced
a product that was too dry, and dust became a problem. This dif-
ficulty was alleviated by re-routing an appropriate amount of the
drying column feed around the flash drying unit and mixing it
with the flash drier product for a resultant moisture product of
7% (Figure 7).
The hot (82°C) gases at the tops of the cyclones were
scrubbed to remove the fine coal dust. The moisture-laden gas
(dust removed) from the scrubbers proved to be a problem. Mois-
ture condensed as the air passed through the colder discharge
ducts on its way to the plant stack. As a result, highly acidic
water had to be removed continually from the stack base and
treated in a clariflocculator (73).
The last component was the clariflocculator, which received
fine coal particles from two sources—the water from the vacuum
disc filter and the water from the wet scrubber that treated the
hot cyclone gases. These products passed through the clarifloc-
culators where the underflow (at 25% solids) fed the initial
surge tank and the overflow (at 4 to 25 ppm) discharged into Lake
Erie (74) . A number of chemicals were added to maintain the ef-
fluent quality within prescribed limits. The first was a caustic
to maintain an effluent pH of 7.0. The second was a coagulant
introduced into the clariflocculator to assist in separating the
fine coal and water. Finally, additives were used to maintain an
oxygen inhibitor concentration of less than 1 ppm in the efflu-
ent.
It has been noted (73) that the effluent from the clarifloc-
culator had fewer suspended solids than the water taken,from Lake
Erie for steam condensing purposes. At that time, the lake water
was rarely less than 60 ppm suspended solids while the clarifloc-
culator effluent ranged from 4 to 25 ppm. An estimated 5 pounds
of coal were lost per hour.
The suspended solids effluent quality is impressive. How-
ever the amount of chemical additives contained in the effluent
must also be considered—the chemical flocculant, the additive
to counter the oxygen inhibitor, and the caustic.
Dust is a problem in any coal-fired power plant, and the
Eastlake plant was no exception. Dauber and Gill (73) summarize
the dust problems in the plant and their solutions below:
The foregoing problems and their solutions cover
the major ones occurring in the coal preparation plant.
However, the unusually fine hot (82QC) dry coal (5%
51
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moisture) intensified and created problems as it was
being transferred by the conventional belt conveyors
to the coal bunkers in the main unit generating plant.
The leakage at the skirts of the conveyor chutes be-
came intolerable, requiring extra men to clean up the
coal dropping from the belts. Dust created at trans-
fer points of the belt became a matter of concern.
Further, when the weather became cold, the warm, moist
vapor from the coal created a very dense fog. This
condensed on the cold conveyor gallery surfaces and
building ceilings. The drippings from the surfaces
were like rain. Where it was below freezing, ice
collected.
Installing seals rather than conventional skirts
on the ends of the coal belt transfer chutes effectively
decreased the leakage. Also, raising the moisture from
5 to 9% significantly reduced the dust problems. A col-
lecting system to remove the dust and moisture-laden
air at the belt transfer points is being installed.
The space above the coal bunkers will be heated. These
steps, it is expected, will give satisfactory conditions
along the conveyor.
The second example of a dewatering system, the Black Mesa
pipeline, avoided some of the problems encountered at the East-
lake plant but at the same time generated new ones unique to
Black Mesa. The Black Mesa dewatering plant flow sheet is illus-
trated in Figure 8.
The Black Mesa dewatering system contains four major compon-
ents: the heat exchangers for raising the slurry temperature,
the solid bowl centrifuges, the pulverizers where the coal is
crushed and mixed with drying air, and the clariflocculators.
The solid bowl centrifuge is the workhorse of this system,
just as the disc filter was in the Eastlake plant. The centri-
fuge rotates at approximately 1000 rpm, and slurry feed enters
in the center. The coal is moved away from the water by a screw
conveyor that is rotating about 11.5 rpm faster than the bowl.
Wear becomes a large problem in the centrifuges. The screw
flights and centrifuge linings wore out too quickly for dewater-
ing to be economical. These problems were solved by installing
ceramic tiles on the screw flights and using a centrifuge liner
of ^stainless .steel. Average centrifuge life then increased from
approximately 1,500 hours to 10,000 hours but is now limited by
the life of the cone liners (17,9). The life of the screw
flights is approximately double the life of the liners so the
flights are refurbished about every second centrifuge overhaul.
Materials and labor costs for centrifuge maintenance in 1976 av-
eraged 10$ per tonne of coal cake (75). There are no adverse en-
52
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u>
PIPELINE „ FUEL SUPPLY LOOPS
^ i i '
SLURRY i HEAT
ST?i?^E <=^ • /-> EXCHANGERS
IAN Kb 1 I I^S\ 1 r _.
(i nay each) L _! ' — ' ci — TJ 1 1 1 1 1 1 1 1
• v X-0
1 T f^ CAKE
1 , 18-20% S
rrrniriuT t ^^"1 MOISTUn
i * " , T M ^ I
I . t SOLID BOWL |
tl CLARIFLOCCULATORl CENTRIFUGES ^T
•^—"/ K
iT^-v UNDERFLOW PULVERIZER
OVERFLOW 1 (5\ TO BURNERS
TO COOLING
WATER MAKE-UP
i
- »^
URFA
E
\
R
i
GAS
BURNER
" 1
DRYING
AIR
FUEL TO
BOILER
Figure 8. Flow diagram Mohave pipeline coal utilization (74).
-------
vironmental considerations associated with the operation of the
centrifuges.
Two centrifuges feed every pulverizer. As the coal is moved
to and through the pulverizer, primary air at 400°C dries the
coal before it is classified and tangentially injected into the
boiler furnace. Dust could be a problem here but the entire pul-
verizer system is enclosed.
The effluent from the centrifuges is sent to the clarifloccu-
lators where chemicals similar to those used in the Eastlake
plant are added to aid in coagulation. The cost of the chemical
additives can be quite substantial. In 1975, for example, chem-
ical costs amounted to $5.60 per dry tonne of coal produced from
the clariflocculators (17). This cost has subsequently been
greatly reduced to $1.10 per dry tonne in 1976 after a switch in
chemicals and manufacturers (9). Most of this cost goes to main-
tenance of the dewatering equipment. Clariflocculator chemicals
now comprise only 5 to 10% of the $1.10.
The overflow from the clariflocculators is used as cooling
tower makeup water, resulting in zero effluent discharge while
the underflow is injected into the furnace*. This injection can
only be performed when the furnace is operating between loads of
600 to 740 Megawatts; outside this range severe operating diffi-
culties, such as slagging or over-pressures, occur (17) .
By February 1976 some 400,000 tonnes of clariflocculator un-
derflow had been produced and not burned for various reasons. The
underflow had to be stored in a total wastewater pond 14 hectares
in area and 3 meters deep. Research is being performed presently
to determine alternate methods for handling this product effec-
tively.
Slurry heating has proven to be highly desirable in meeting
the requirement of 25% moisture in the coal feed to the furnace.
The heat exchangers currently have the capability of raising the
slurry temperature to 88°C, but the optimum appears to be 82°C
(17). The Mohave operation is now heating slurry to only 82°C
because of limitations in the centrifuge driveshafts. It seems
that the drier coal exerts a greater load on the driveshaft than
that for which it was designed, and a large number of driveshaft
failures result when slurry temperature is raised above 82°C.
With extra-heavy-duty driveshafts and heating to 88°C it is ex-
pected that the additional heating of primary air with gas burn-
ers will no longer be necessary, and the recycling of the clari-
flocculator underflow back to the centrifuges can be accomplished
according to the original design plan.
Foreign practice, particularly in the United Kingdom and Ja-
pan, makes use of an oil additive to coal slurry to encourage ag-
glomeration of 2 to 5 mm balls which can be removed by screening
54
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The Mohave plant does not have the dust problems that the
Eastlake plant experiences because of the higher moisture content
of Black Mesa coal. However, coal is stockpiled at the Mohave
plant, and this action has the potential for dust control prob-
lems. The stockpiles at the Mohave plant utilize chemical seal-
ing sprays to handle the dust problem, as noted by Snoek, et al.
(74) :
Here (at Mohave) a pile about 200 meters long, 50
meters wide and 6 meters high of dewatered coal was
stored under adverse conditions of high winds and low
humidity. The pile at its maximum contained about 85,000
tonnes of coal. The dust problem was controlled very
nicely by spraying the pile with a sealing compound.
There was little spontaneous combustion problem
with this pile, less than might be expected with rail
coal. One would expect less spontaneous combustion prob-
lems because the fine coal restricts air circulation
through the pile.
Another problem confronting the Mohave plant is the process-
ing of outcrop coal. When a slurry containing coal with lower
pH, lower heat value, higher ash, and higher inherent moisture
is directed to the centrifuges, difficulties such as overloading
occur. Difficulties also occur in the clariflocculators when
processing this coal. As it has been noted (17) , "The amount of
chemicals required to treat this centrate (of outcrop coal) in-
creases in magnitude by five, and at times no amount of chemicals
can treat it."
Although each facility has or had its own particular opera-
tional difficulties, the one thing that both the Cadiz and Black
Mesa pipeline dewatering facilities had in common was the use of
clariflocculators and the addition of chemicals to aid in coal-
water separation.
Although Black Mesa does not discharge any effluent into a
local water course, it does use large areas for wastewater evap-
oration. A possible impact, although slight, might be the at-
traction of migrating water fowl to these ponds. Chemicals used
in the clariflocculation process for corrosion inhibition of pH
adjustment could prove to be harmful to these birds. Therefore,
even though the Mohave plant approximates zero discharge, its
semi-effluent from clariflocculators could have an environmental
impact. A way to minimize the impact would be to choose chemi-
cals carefully to aid in coagulation and corrosion inhibition or
to neutralize the chemicals after the job is finished.
Similarly, the chemicals used in conjunction with clarifloc-
culator operation in the Eastlake plant—the oxygen inhibitor,
the caustic, and the flocculant—produced an impressive solids
55
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effluent quality; on the other hand, the cost to other water
quality variables must be simultaneously considered. While im-
proving one particular water quality variable, other variables
could be degraded. Careful choice of chemical additives must be
made to minimize any adverse environmental impacts.
There is an alternative to slurry dewatering that should be
mentioned at this point. The alternative is the direct burning
of a coal slurry. This option was attempted in 1961 when the
Werner power Station of the Jersey Central Power and Light Company
at South Amboy, New Jersey, successfully fired 10,000 tonnes of
coal in concentrated slurry form in one month (74). Cyclone fur-
naces, originally designed for poor grades of coal and high vari-
ations in coal feed moisture, were instrumental in making the
test program a success.
The coal slurry used came either directly from the terminus
of the Cadiz-Eastlake coal slurry pipeline or from the Georgetown
Preparation Plant of Consolodation Coal Company, which supplied
the coal for the Cadiz pipeline. The average concentration of
the slurry burned was 67% coal by weight.
As expected, the furnace operated at a slightly lower effic-
iency (about 4.5%) while burning slurry when compared to regular
plant feed. This was because of the extra moisture and an in-
creased exit gas temperature (74). Nevertheless, the test was
considered an unqualified success.
The drawbacks were not immediately discernable, but because
of the higher combustion temperatures, high concentrations of ox-
ides of nitrogen were produced in the stack gas. The concentra-
tions exceed today's Federal EPA emission standards, and present-
ly there is no adequate flue gas scrubbing technology available
for NO removal (74).
X.
One aspect of dewatering concerns the possible discharge of
effluent that is contaminated with corrosion inhibitors. While
most slurry pipelines do or will terminate at a zero discharge
power plant, there may be situations where a coal slurry pipeline
terminates at a barge or rail facility (Figure 9). Unless an al-
ternate use were found or the water carrier were somehow returned
to the origin of the slurry pipeline, the water would obviously
have to be discharged into a local water course. This action ne-
cessitates treatment, but the kind and amount of treatment de-
pends on the chemicals utilized.
Previous discussion dealt primarily with chemicals involved
in coal separation, but consideration must be given to corrosion
inhibitors as well. Jacques and Neil (77) list the various cor-
rosion inhibitors currently available with a relative rating of
effectiveness as well as environmental desirability.
56
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TO POWER
PLANT COOLING
WATER SYSTEM
A CLARIFLOCCULATOR
SLURRY
~l
FEED TANK
HEAT
EXCHANGERS
1
' 1
STEAM
r
EFFLUENT j
FILTER
CAKE
THERMAL
DRIER
OEWATERED
COAL
POWER PLANT
OR
TRANSSHIPMENT
Figure 9. Pipeline coal dewatering flow diagram (74).
-------
Hexavalent chromium is an excellent corrosion inhibitor but
has poor environmental acceptability. EPA standards require less
than 0.05 ppmconcentrations in plant effluents. There are some
electrochemical devices commercially available that can remove
chromium for an operating cost of from 1.3 to 2.6 cents (1975)
per cubic meter treated. One manufacturer has a large device
(with a capacity of 4.5 cubic meters per minute) capable of such
a process (78). The Black Mesa pipeline, if it were to discharge
all of its water resulting from its clariflocculator operation
and if the water contained chromium, would require two such de-
vices, but they would not be working at full capacity. At the
rate of 3.06 cubic meters per minute per power plant unit—and at
a top cost of 2.6 cents per cubic meter treated—the Black Mesa
facility would expend approximately $234 on operating costs per
day to treat for a theoretical concentration of chromium in a
theoretical effluent discharge.
In conclusion, it appears that most of the physical aspects
of coal water separation have no adverse environmental impacts.
However, chemicals involved in dewatering processes do have pos-
sible adverse environmental impacts. Careful selection of chemi-
cals must be made to minimize those impacts.
58
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SECTION 5
PIPELINE CORRIDOR SELECTION AND CONSTRUCTION
Corridor selection is made according to the same criteria
used in designing the entire pipeline system—economics, engin-
eering, and environmental impact (the three E's) .
Corridor selection is an important aspect of any pipeline
system because it influences the design, operation, and longevity
of the pipeline. Because the cost of steel pipe constitutes a
substantial portion of the total cost of a long-distance piper-
line, economics dictates that the route be as short as possible.
Hence, the first step in route selection is to draw a straight
line from source to terminal. A right-of-way is selected, usu-
ally 25m wide for construction and maintenance purposes, as well
as for a balanced design, possibly up to a kilometer in width for
a "corridor of influence." The latter width is for studying en-
vironmental impacts. External constraints will eventually flex
the straight line route into a final design route.
The constraints are basically societal and engineering con-
straints. The latter are usually natural obstacles which can be
accomodated because pipelines can go around, over, under, or pos-
sibly pass through obstacles when proper protective measures are
used. Engineering constraints may be accommodated using the fol-
lowing rules:
1. Avoid excessive trenching in rock to reduce excavation costs.
2. Slurry pipelines may require a grade limitation (e.g., coal
slurry pipelines usually do not exceed grades of 15 to 20%,
either up or down),
3. Circumvent large bodies of water such as lakes or wide river
crossings.
4. Where water crossings cannot be avoided, utilize existing
railroad or highway bridge supports whenever possible.
5. Water crossings also can be made by
a) floating the pipe on the water surface when the
water level is devoid of surface fluctuations and
waves (e.g., a small sheltered lake without navi-
gation) ,
b) laying the pipe on the bottom of the river or lake
where stable bottoms exist (e.g., regulated rivers),
or
59
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c) burying the pipe in a trench in the river or lake
bottom when the bottom shifts because of wave forces
or stream currents.
6. Rivers with steep banks can be crossed by suspension bridges
built exclusively to support a fully-loaded pipeline sub-
jected to dynamic stresses. These types of bridges are sim-
ple in design and more aesthetically pleasing with their
long, graceful appearance.
Societal constraints, on the other hand, tend to be more
complex. Basically, they occur wherever potential environmental
impacts may be encountered, such as in National forests, in State
parks, on Indian reservations, in wildlife habitats, on histori-
cal or archeological sites, and in high-density population areas.
Since the right-of-way for a pipeline corridor is narrow
(about 25m), construction may be permitted to pass through an en-
vironmentally sensitive area. Disruption is greatest during the
construction stage. If its impact can be tolerated for the rela-
tively short construction period, then the impact is almost non-
existent during the operation of the pipeline. This will be dis-
cussed in more detail later.
Numerous techniques are available for pipeline route plan-
ning, but probably the most versatile is that technique which
uses a digital computer to evaluate the three E's for grid cells
along a proposed pipeline route (79) . An initial route or alter-
nate routes are selected, avoiding natural obstacles discussed
previously as engineering constraints. A convenient grid system
is selected with natural and cultural variables plotted by cell
along the proposed route. The corridor of influence is approxi-
mately a kilometer wide for convenience but can be easily changed
to adapt to any particular project requirements.
According to Stastny's (80) method, the individual cells are
evaluated on eight weighted criteria: 1) vegetation, 2) topo-
graphy, 3) water and wet land, 4) transportation, 5) popula-
tion density, 6) land use constraints, 7) future land use, and
8) soil or agricultural capabilities. All criteria are assigned
a value from 0 to 10; the higher the value, the higher the im-
pact (and hence the less desirable for a pipeline). The data
necessary to assess the cells come from recent aerial photos,
USGS topographic maps, county master plans, historical societies,
and any other available sources.
The data usually can be plotted in any of the following
ways: 1) as a percentage of cell coverage, 2) as the number of
times occuring in a cell, and 3) as the maximum or minimum values
in a cell. For example, vegetation could be measured as a per-
centage of cell coverage, local roadways could be assessed as
mileage and class occurring in a cell, and elevation could be as-
sessed according to maxima, minima, and volume above sea level.
60
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In effect, a land resource-use inventory is established.
When all the data are plotted, a computer draws a family of
maps or overlays, one for each of the eight criteria, and corri-
dors are selected for each overlay on a minimum impact basis.
The next step is subjective: a multidisciplinary team assigns
each map with a particular weight. Using the weighted data, the
computer produces a final composite map, and a final pipeline
corridor of least environmental impact is chosen. Only after a
field reconnaissance is performed and the findings incorporated
into the data can the final pipeline route be selected. The
flexibility of this approach allows the addition or removal of
constraints,or the variation of cell size to reflect the accuracy
desired.
The goals of this approach or any pipeline route selection
technique are the following (80):
1. To minimize damage to natural systems
2. To minimize conflict with existing land uses
3. To minimize conflict with proposed land uses
4. To minimize conflict with culturally significant
features
5. To minimize total investment
6. To maximize potential right-of-way sharing
The final goal--maximizing potential right-of-way sharing—of
any pipeline route selection deserves additional comment. Buck
(44) expanded on this subject well:
A coal slurry line can utilize right-of-way corri-
dors. Perhaps an abandoned pipeline can be refurbished
to transport coal. The most obvious common corridor
use/ exploited by a slurry line, is the electrical
transmission line which leads directly to the generator,
the consumer of the coal. A coal slurry line built in
an existing corridor can share the maintenance, the sur-
veillance and even the emergency facilities and commun-
ications networks of the utilities already in that cor-
ridor.
An area already developed and maintained rarely suf-
fers excessive environmental damage from the addition of
a slurry line...The common corridor usage usually allows
a ready acceptance of the coal slurry line by the public
and agencies alike.
An example of such utilization of an existing right-of-way
occurred in the construction of the Bruce Mansfield Power Station
Project (81) . The project utilized an old, abandoned railroad
right-of-way on property procured from the bankrupt Penn Central
Railroad to locate a slurry pipeline for scrubber sludge treated
with a stabilizer. The line is approximately 11 km long.
61
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The concept of utility corridors is not new. Telephone and
power lines are carried on common poles in utility easements in
suburban areas. Many large cities are underlain with utility
tunnels carrying telephone, electric, gas, steam, sewer, and
water systems. Europe has had extensive overland utility corri-
dors for decades simply through necessity—because of the scar-
city of land.
CONSTRUCTION
The construction of coal slurry pipelines does not differ
appreciably from the construction of oil and gas pipelines. Oil
and gas, though, are more hazardous than coal-water slurries.
By following the same construction practices for oil and gas,
coal slurry pipelines automatically meet the environmental and
safety requirements for oil and gas pipelines. The API Bulletin
on Construction Practices for Oil and Products Pipelines contains
more than 75 pages pertaining to methods of construction and spe-
cifications. These are not reproduced in detail here but major
techniques can be highlighted. Minimum safety standards are gi-
ven in the Code of Federal Regulations, 49-Transportation, Parts
100 to 199, Revised, 1973, by the Office of Pipeline Safety, U.S.
Department of Transportation. Assuming that all the necessary
right-of-way permits are procured legally, there are eight activ-
ities that may potentially produce an environmental impact in the
construction stage. They are the following: 1) clearing and
grading, 2) ditching (including river, highway, and railroad
crossings), 3) storage, haulage, and stringing of pipe, 4) weld-
ing the pipe, 5) coating and wrapping the pipe, 6) backfilling
the trench, 7) cleaning up, and 8) testing the system.
During the construction of a coal slurry pipeline, activi-
ties 1 through 7 can be accomplished (according to the API bul-
letin) in approximately 10 to 14 days at any given point along
the pipeline route when conditions are ideal (82). However,
according to other sources (83) , "It takes about four days for a
pipeline construction spread to move past a specific point; four
days from the time the ground is open to the time it is filled
in." Figure 10 illustrates these various activities (although
they are never spaced that close). Pipeline progress is usually
3 km per day with crews spread out over 30 km. Each activity
does have the potential of producing an environmental impact and
is considered individually.
Clearing and grading is the first aspect of construction
that strips topsoil and lowers the grade to the desirable design
level. It should be noted that minor work on fences and route
surveying precede the actual clearing and grading and these ac-
tivities pose a very slight environmental impact potential.
Clearing and grading constitute short-lived activities. If they
are not executed with the proper care, pollution of local water-
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BACKFILLING
STRINGING
-CLEAN-UP AND
RESTORATION
-PIPE COATING
SCALE CONDENSED FOR ILLUSTRATIVE PURPOSES
Figure 10. Typical pipeline construction spread.(40)
sheds can occur. If a severe rainstorm should occur while clear-
ing or grading and the usual safeguards are not taken, the runoff
could pollute a local stream with suspended solids. The result
of such an occurrence would have to be assessed on a case-by-case
basis. However, it should be noted that this impact possibility
is common in the construction of almost any overland travelway,
whether highway, canal, railroad, or pipeline. The solution to
the problem is also as common: small catch basins or ponds can
collect the excessive runoff and allow the suspended solids to
settle out before the water is discharged into the watershed.
The principal hazard with ditching, likewise, is pollution
from runoff. In extreme cases, wind erosion of the excavated ma-
terial could become a problem. Fugitive dust is another problem
common to most construction projects. The solutions include
spraying of chemical soil stabilizers or simply using water
trucks to wet the exposed material. Although the pipeline route
reconnaissance team may detect archeological evidence, ditching
as well as clearing and grading offers the highest potential for
archeological discovery. If a competent archeologist is not on
site, it is recommended that one be on call just in case items
of historical or prehistoric interest are uncovered.
River and lake crossings have already been discussed (see
page 59) .
Highway and railroad crossings must also be done with care
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to maintain the integrity of the sub-structure of the travelway.
If improperly executed,a crossing could transfer loads from the
roadbed to the pipeline. Repeated loading could lead to external
stress on the pipeline and possible structural failure. Probably
the best method for crossing railways and highways is tunneling
under the crossing. Usually a tunnel can be augered and encased
by a rigid pipe through which the slurry pipeline is passed and
supported. This method of crossing is least disruptive and rela-
tively inexpensive, and it usually ensures minimum stress distri-
bution on the slurry pipeline. It should be noted that highway
and railroad crossings are nothing new to pipeline-laying crews,
and every engineering safegaurd available is employed.
The storing, hauling, and stringing of pipe does not consti-
tute much impact because these activities occur adjacent to the
trench. Storage of pipe at centrally located facilities may con-
flict with land uses, but at the rate pipeline construction pro-
gresses the storage site would be temporary.
Oil and gas pipeline codes presently are suitable for coal
slurry pipelines (84) although the slurry pipeline industry is
in the early stages of establishing a code committee. If welding
is performed strictly according to code, the only impact from
welding activities would be the discarding of expended electrodea
Care taken by the welders would elminate this litter. It should
be noted that some pipeline companies employ automatic welding
machines. These machines probably use electrodes more efficient-
ly and completely, and their use would result in even less impact
because of welding activities. While the possibility of inade-
quate weldsds present, any such flaws in the system would be de-
tected when the pipeline is tested by X-rays for structural in-
tegrity.
Coating and wrapping of pipe according to established codes
would also offer insignificant impacts. Again, litter-consisting
of unused material or packaging material—would be a minor nui-
sance. The biggest potential impact that might develop would oc-
cur if the coating and wrapping were not done properly and cor-
rosion occurred as a result. Corrosion would cause the pipe to
become reduced in thickness, subjecting the pipe to possible
leakage in time (or even rupture if the allowable design pressure
were exceeded). However, the coating and wrapping is performed
according to code and the possibility for corrosion is remote.
The tradition of good workmanship in pipeline design and in-
stallation is evident from the age of many water, oil and gas
pipelines, some still operating after more than 100 years. Long-
distance slurry pipelines are installed with a life expectancy of
20 to 50 years, depending on the abrasivity of the solids. Coal
slurry pipelines are expected to last more than 35 years.
The backfilling of the trench must be done with care. Soil
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should be replaced to duplicate the original conditions. All
subsurface soil should be replaced first, finishing with the lay-
er of topsoil. (The two are easily segregated in the clearing
and grading stage). Rock which might damage the wrapping and
coating of the pipe should not be placed in contact with the pipe.
Compacting and final grading to the rough original contour is
normally performed.
In some cases, revegetation to the original growth is nec-
essary while in other instances it is not. For example, when re-
vegetating an agricultural area, the revegetative species should
closely .approximate, if not duplicate, the original ones so as
not to be in conflict with the intended land use. On the other
hand, consider the case of the pipeline route located in the
middle of a forest. Revegetation practice might be guided by the
possibility that the pipeline right-of-way could serve as a fire-
break. From all viewpoints that is exactly what the completed
pipeline right-of-way would appear to be, a firebreak. In addi-
tion to the dual use of the pipeline right-of-way is the obvious
potential for large tree roots damaging the pipeline, and the
pipeline Eoute—for the sake of safety—should, therefore, be de-
void of large trees.
The final construction activity is testing. There are many
different methods of testing a pipeline, including x-raying the
welds, pressurizing the line with air or water, or utilizing
ultra-sonics to actually listen for leaks (85) . Cracks as small
as 20% of the material thickness can be located with 90% proba-
bility and 95% confidence. This can be compared with locating
leaks of 70% of the thickness when conventional radiographic
techniques are used. The increased sensitivity is obtained by
improving several image characteristics (86) . Hydrostatic test-
ing is done before the trench is backfilled. Dynamic testing of
a slurry pipeline occurs after completion of construction and
will be examined shortly.
Thus, while it appears that there are construction activi-
ties capable of producing environmental damage, they tend to be
short-lived and of a minor consequence.
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SECTION 6
OPERATION AND MAINTENANCE
Operation and maintenance of a slurry pipeline extend to the
entire system and involve attention to slurry preparation, pipe-
line transportation, and slurry separation. Even though there
may be separate ownership of each subsystem, successful operation
requires coordination and cooperation from each part. Operation
and maintenance are required for the following:
1. The water supply source and its collection system
2. The water pump stations
3. The water supply pipeline
4. Coal source and its mining system
5. Coal washing facility
6. Slurry preparation facility
7. Slurry pipeline
8. Slurry pump station
9. Power supply system
10. Slurry dewatering facility
11. Overall physical plant upkeep
Operation and maintenance of the first three items are con-
ventional whether the water supply comes from groundwater or sur-
face water reservoirs. Coal mining and cleaning are also conven-
tional, whatever the transportation mode. Similarly, items 9 and
11 are conventional and require no elaboration. Slurry dewater-
ing was discussed in an earlier section.
The slurry preparation facility is essentially conventional
but with a few exceptions. Because of the limited flexibility in
the optimum design of a long-distance slurry pipeline, the size
distribution of the coal cannot be varied widely without a con-
comitant change in power...requirements. The operation of the pre-
paration plant must be rigidly controlled to prevent excessive
generation of fines, which are difficult to dewater at the pipe-
line terminal, and to prevent excessive generation of coarse coal
particles, which accelerate pipewall wear and require more power
for pipeline transportation. Control is achieved by screening
the coal, recirculating over-size coal back to the crushers and
grinders, and preparing the slurry to the appropriate solids con-
centration in holding tanks prior to pipelining. When unconven-
tional slurries are to be experimented with, a test loop is some-
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times connected to the holding tanks to develop pipe flow infor-
mation on these slurries before they are switched over to the
main pipeline for long distance transport.
Experience at Black Mesa (17) has shown that outcrop coal
with higher ash and water contents is difficult to dewater and
burn. These problems can be mollified, not at the slurry prepar-
ation plant but at the coal mine where blending of outcrop coal
with higher quality coal can be achieved. A better long-term
solution might be to install a washing plant facility to reduce
the ash content and, possibly, the sulfur. .This would leave some
of the waste products at the mine for easy disposal and would re-
duce the amount of waste .products and emissions at the power
plant.
Operation and maintenance of the pipeline and pumping sta-
tions would appear to offer the greatest danger of environmental
impact and pollution. Pipeline shutdown and utilization of the
dump ponds at pump stations would appear to be the most probable
undesirable event that might occur.
PIPELINE SHUTDOWN
As shown in Section 2, external causes are responsible for
most pipeline accidents. When no external causes produce a fail-
ure, three internal causes might develop pipeline shutdown: a
leak, a rupture, or a cessation of flow due to a solids plug.
In the late stages of construction, structural leaks are lo-
cated during hydrostatic testing. According to the ANSI B31.4
code (86) , a new petroleum pipeline must be subjected to a hydro-
static pressure level of 1.25 times its maximum operating pres-
sure for a period of 8 hours. Though the code is not mandatory
for slurry pipelines, both the Consolidation Coal and Black Mesa
pipelines met this code requirement comfortably (87) .
After a period of operation (as long as several decades) ,
corrosion leaks can develop from improper pipe protection (i.e.,
coatings, wrappings, and cathodic protection).
Pipe protection is required externally from corrosion and
freezing and internally from erosion and corrosion.
External Protection
There are several corrosion protection methods for steel
pipes (88). In order of increasing effectiveness, they are
ranked as follows:
1. Use heavy wall thickness. This is expensive and only pro-
longs the rate of deterioration.
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2. Improved backfill. Granular clean sand is recommended but is
still prone to infiltration of leached salts.
3. Loose polyethylene sheets can be used (and have been used
since 1965). These 8-mil thick unbonded sheets which encase
the pipeline are forbidden by code on gas pipelines but have
been used on slurry pipelines.
4. Cement mortar coating is better than the above but still vul-
nerable to chlorides and stray electrical currents.
5. Use insulating coatings,the most popular of which is hot ap-
plied coal tar enamel. This has been used since 1854 in Eng-
land and for over 100 years in the United States. Coating is
usually preceded by chlorinated rubber primer and followed by
wrapping of fiberglass paper or asbestos felt.
6. Cathodic protection is considered the superior form of exter-
nal protection when used with one of the above protective
measures. Long underground pipelines can deteriorate elec-
trolytically because of differences in electrical potential.
Induced currents from power lines, dissimilar metals, and
soil composition cause an electrolytic action in which the
pipe is consumed. Cathodic protection involves the reversal
of the natural tendency for the uncontrolled discharge of
current from anode areas on the exterior surface of buried
ferrous metal pipelines. To reverse this circuit, external
sacrificial anodes (usually magnesium or zinc) are buried in
the soil adjacent to the pipeline and connected electrically
to the pipe. The size, number, and spacing of anodes re-
quired is dependent upon the particular installation and en-
vironment. The external anodes result in the pipeline be-
coming a cathode, with no external corrosion taking place on
the pipeline. Cathodic protection of an uncoated pipe, how-
ever, is considered to be uneconomical.
7. Normally the pipeline is buried below the frost line. Where
it must be exposed to freezing temperatures, heat trace
cables and insulation are used.
Internal Protection
Coal slurries transported in long-distance pipelines are so
fine that erosion of the pipe wall is minor. The erosion is due
primarily to the ash in the coal. Because the coal is ground
finely, the transport velocities may be kept low (<2m/s), thereby
reducing erosive wear. Corrosive wear is due to the oxygen in
the water and is thought to be of the same order of magnitude as
erosive wear. The two wearing phenomena act in concert as a sy-
nergistic system, resulting in greater total wear than the sum of
the two components. Corrosion builds up an oxide scale on the
pipe wall, which is abraded by the coarser coal particles. Nev-
ertheless, the total wear rate is much less than with most miner-
al slurries.
Internal protection can be achieved several ways:
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1. Increase wall thickness. This is an expensive method, one
used at Black Mesa.
2. Use oxygen inhibitors. This method was tried on Consolida-
tion Coal pipeline. Various cost and environmental disad-
vantages exist.
3. Line the pipe interior. A method of the future, this appears
to be promising when use is made of interior coatings rather
than linings.
4. Remove the oxygen. Another method of the future, this also
may be expensive.
5. A combination of the above or partial use of the above meth-
ods may be used.
Jacques and Neil (89) examined the above schemes and con-
cluded that long-distance coal slurry pipelines would probably
benefit from a lining of the pipe for the first segment followed
by increased wall thickness for the remainder of the distance.
The oxygen in the water would be consumed by the coal usually
within the first 80 km, thereby reducing the need for a high cor-
rosion allowance in pipewall thickness. For example, Black Mesa
was designed for a corrosion allowance of 0.3mm/year and so far
is on schedule. When the dissolved oxygen level is below l/2ppm,
the corrosion rate decreases markedly and the corrosion allow-
ance can be reduced to 0.075mm/year.
Internal coatings and linings which show promise are poly-
urethanes and epoxy-polyamids. Because the pipe would be fac-
tory-coated, part of the coating would be burned off as each
joint was field-welded. The interior coating would have to be
repaired in the field. Although there are presently no means to
detect "holidays" in coating, it may not be crucial to the pro-
tection of the pipe if a few pinholes occurred in the coating.
Another possible major advantage of coatings might be a reduction
in wall friction if the coating provides an interior finish
smoother than steel. The disadvantage of coatings is that they
might deteriorate in time from abrasive wear, particularly on the
invert of the pipe. Tests are required to evaluate coatings.
Such technical developments have this aim in common—to pro-
duce a more economical and safer pipeline without the use of oxy-
gen corrosion inhibitors, some of which are environmentally unac-
ceptable .
Leaks and Ruptures
A pipeline leak by definition is a small discharge through
a pinhole, a loose pipe connection, a weakened weld, or a valve
on a branch pipe which lacks total closure. Light aircraft fly
pipeline routes on a 2-week basis, flying as low as 30 meters,
but a pipeline leak may not be evident from an aerial surveillance.
Depending on the size of the leak and upon the operator s exper-
ience, a reduction in flow at the terminal may be shown by a mag-
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netic flow-meter when compared to a higher flowmeter reading at
the head end of the pipeline.
It is unwise to assume that a pinhole leak will plug itself
with fine solids. Experience has shown that the water escapes,
resulting in an increase in solids concentration. This in turn
increases the energy requirement for pipeline transportation.
When a leak is suspected but cannot be detected physically, the
slurry should be replaced by clear water and a leak detector in-
stalled. An ultrasonic leak detector (84) with an electronic re-
cording instrument is placed in the flow (much like a scraper
pig). It measures the noise generated by flow of a liquid
through a small hole and can locate a leak within 100 meters.
A rupture is more serious than a leak because it is usually
instantaneous, leaving little time to take corrective action.
Generally, ruptures are caused by pressure transients and occur
at the weakest stress area in the pipeline (usually in thin-wall
or eroded pipe). Pressure transients are caused by sudden (im-
proper) pump start-up and shutdown (power failures) and fast
valve stroking. Pressure transients can be calculated quite ac-
curately for single-phase liquids. The transients in slurries
arp usually moderated by the presence of solids (90) and are,
therefore, more difficult to evaluate. Protective devices in the
form of surge dampeners and pressure relief valves (rupture
discs) are installed in a location where the pressure waves can
cause excessive pressures in the pipeline and where they are ac-
cessible for maintenance. Should they fail to respond properly,
the pipeline can rupture. Ruptures are usually a meter or two
in length and several centimeters wide. The reduction in flow
and pressure is picked up essentially at the speed of sound by
instrumentation at the pump stations. The pumps are stopped and
block valves close automatically. If no block valves are pre-
sent, the ruptured line drains all continuously higher pipeline
elevations. As the slurry drains through the rupture, the pro-
pagation of the slurry will be influenced by the topography of
the land at the rupture point. For example, steep gradients will,
produce a long, narrow plume of slurry which could extend a con-
siderable distance; a flat gradient will produce a localized,
deeper puddle. Unless the coal is highly acidic, which is unlike-
ly, it is expected that the water would infiltrate the soil
quickly and evaporate without undue harm to the environment. Ul-
timately, the dried fine coal might be blown by the winds. Since
coal is essentially inert, adverse impact on the environment is
not anticipated, at least not more than from spillage when a unit
train derailment occurs. Needless to say, the safety hazards
from ruptures of gas and petroleum products pipelines are much
greater than those of coal pipelines.
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EMERGENCY STORAGE
Most long-distance slurry pipelines utilize emergency stor-
age. Three types are possible, depending on location of the
pipeline. Water ponds may be located at high points of a pipe-
line for back-flushing the system, in the event of an unscheduled
shutdown. Water released by gravity flows back to each pump
station to a dump pond, removing most of the solids in the pipe-
line on its journey. This type of storage is not used frequently
because of the difficulty in obtaining water at high elevations.
Commonly, pump stations have both a water storage pond and a
slurry dump area. The two storage areas are constructed at the
same time if the land is available. In the event of an unsched-
uled shutdown, where start-up is difficult because of a high sol-
ids concentration, each segment of the pipeline upstream of a
dump pond can be pumped into the dump pond by the previous boost-
er station. The advantage is increased flexibility,in'the oper-
ation of the pipeline. Since a long-distance slurry pipeline at-
tains its economic advantages in high-volume throughput and high
use factors, the role of emergency storage is to minimize shut-
down time and lost capacity. The slurry storage pond is a last
resort, to be used only when a high concentration slurry cannot
be pumped through to the power plant. The goal is to avoid sol-
ids dumping because it represents lost revenue from lost product
and downtime. Usually the.pump stations are somewhat remote, and
reclamation of the coal is difficult. It is too costly to re-
slurry the coal and put it back into the pipeline. Slurry dumping
is too infrequent to warrant the cost of a separate slurry pump
circuit for the return of dumped solids to the pipeline.
Pipeline operators prefer to keep the solids in the pipeline.
When pumping difficulties are encountered, operators prefer to
add dilution water. If water can be added at downstream pump
stations, the preparation plant gains time to adjust the slurry
properties while the pipeline is still operating. Without this
flexibility, the pipeline operation would take longer to correct
if water is available only at the main pump station.
Pipeline designers want to omit dump areas and water reser-
voirs at the booster pump stations in future pipelines since
these are to some extent, redundant. The operators, on the other
hand, see the emergency ponds as a strong advantage in maintain-
ing high use factors for the pipeline and in preventing coal
losses by dumping. Black Mesa experience (91) has shown that
little excess water is pumped to the power plant during start-
ups. There is a tendency to transfer water from one station pond
to the next station pond downstream during this operation.
Slurry dump ponds are customarily designed for two dumpings
of the pipeline volume upstream and downstream of the dump area.
A dyked impoundment area is usually adequate. A deep pond is re-
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quired to reduce evaporation if there is a desire to maintain the
coal in slurry form; a wide, shallow pond is required if dry
coal is desirable. If the coal dries out and is subject to wind
losses, a binder can be sprayed on the coal such as is done to
hopper cars.
The third location for emergency storage is at the lower el-
evations in the pipeline between pump stations. Automatic dump
valves and an impoundment area are necessary. Normally this type
of emergency dumping is reserved for steeply inclined pipelines
that exceed the suggested maximum slopes (15 to 20%) for slurry
pipelines. A pipe is installed at steep angles because of topo-
graphic constraints. Steep pipes, however, produce two major
disadvantages in slurry operation: slack flow and potential
plugging during shutdown. Slack flow means that a pipe is flow-
ing partially full at a higher velocity than normal and under a_
negative pressure. These two effects can cause localized invert
wear from erosion and can promote cavitation. The higher velo-
city accelerates erosion by imparting higher kinetic energy to
the solids. Cavitation results from low pressures (at the vapor
pressure of the liquid), producing bubbles which move downstream
to a higher pressure area and implode, creating local structual
damage (pitting) to the pipe. After shutdown the solids in the
steep pipe slide downward and block the entire cross section of
the pipe. Such a pipe is difficult to unplug with a pump. Vir-
tually all unplugging techniques require fluidization of the
settled solids before flow can be initiated. This is readily
accomplished when a liquid layer exists above the settled solids.
A slow start-up will move the water first, eventually entraining
the solids until full suspension is achieved. If the entire pipe
cross section is blocked with settled solids, the water will com-
pact the plug in an attempt to clear it. Unless the plug can be
blown free into a nearby dump pond, it may be almost impossible
to break it by pump pressure alone.
While fast-settling slurries would have to be dumped auto-
matically upon pump shutdown, slow-settling slurries may provide
time (up to several days) to take corrective action to restart
the pumps after unplanned shutdowns. Again, operator preference
is to use the ponds only as a last resort. Their choice is to
batch high-concentration slurries with slugs of water to reduce
the pressure drop and to keep the coal in the pipeline.
The environmental effects of dumping into ponds would be
minimal. The dump ponds can be lined to prevent seepage of
coal or water from the slurry into the local groundwater supply.
There are a number of ways, then, to empty the dump ponds. The
coal could be dredged and hauled away in trucks, the coal could
be returned to the slurry pipeline during a water run (an un-
likely situation), or the coal could be left in place by letting
the water evaporate. The last action could result in an adverse
impact if the dried coal is exposed to the elements. Wind might
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suspend the coal dust, blowing it over the local landscape An-
other impact involves the possible attraction of migratory or
indigenous waterfowl to the dump ponds. The toxicity and pH var-
iations of these ponds would be harmful to the birds. These im-
pacts, blowing of coal dust and attraction of water fowl, can be
minimized by utilizing a chemical treatment which would detoxify
the slurry and, at the same time, stabilize it against the ele-
ments. The dump ponds and the rest of the pump station also can
be an impact simply by occupying land that could have a differ-
ent use. ^As slurry pipeline experience is broadened, it may be-
come possible to eliminate or reduce dump ponds and thereby al-
leviate this impact somewhat.
Pump stations need a source of power. Stations are usually
in remote locations and are electrically powered. The power
lines running to the pump stations tend to be a lightning target
and, perhaps more important in any consideration of environmental
impact, present a visual impact.
Another area of impact associated with slurry pipelines con-
cerns the population increase necessary to provide the manpower
to operate it. Unlike other transportation modes, coal slurry
pipelines are not labor intensive. With automation one man can
operate the Black Mesa pipeline—although the normal number is 53
men, with 38 at the preparation plant. The proposed ETSI line
will require 335 men while a railroad hauling the same amount of
coal per annum would require 2570 men. Compared with the rail-
road alternative, the impact associated with the increase in an
area's population because of the operation of a pipeline is min-
imal when viewed from the standpoint of increased housing and
land use.
The operation of a slurry pipeline may also have beneficial
impacts in air quality at the power plant where burning of the
slurried coal takes place. Ash removal from the coal before
transport is a very attractive possibility from an engineering
standpoint. Ash removal reduces energy requirements, coal de-
gradation, and pipeline abrasion. At the same time, ash removal
would reduce air and water pollution at the power plant. Ash re-
moval would probably not be implemented if rail transportation
were employed.
START-UP PROCEDURES
Dynamic testing of a slurry pipeline occurs after completion
of construction and involves a sequence of operations similar to
the following:
1. A scraper pig is pushed through the pipeline by compressed
air or water to clean out installation debris and to check
for any obstacles to flow.
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2. Clear water is pumped through the pipeline to check equipment
operations and instrumentation (pumps, valves, flowmeters,
etc.)
3. Slurries are pumped through in low concentrations, eventually
building up to design concentrations, while checking out
equipment operations and instrumentation.
4. Shutdowns and startups (both instant and delayed) are prac-
tised to determine any difficulties in operation. At this
time dump valves and pressure relief valves are tested.
Anti-plugging procedures are examined and modified also.
The purpose of this testing stage is to determine the limi-
tations of the pipeline system before it is put into produc-
tion. Attempts to put the pipeline into immediate production
without adequate dynamic testing may lead to serious reduc-
tions in use factors at a later date.
PERIODIC TESTING
After some period of operation (usually six months or a
year) certain procedures are recommended to evaluate the pro-
jected lifespan of the pipeline.
A recent development is the AMF Tubescope (92). It is es-
sentially a smart pig—a metal cylinder driven through the pipe
by water pressure. The smart pig has self-contained sensing
units which can analyze wall thickness and corrosion throughout
the entire length of the pipeline. These data are recorded by a
self-contained magnetic tape unit during the inspection, and the
tapes are analyzed later in the laboratory. The pipeline is in-
spected with the Tubescope at or near start-up of the system to
establish a base reference and then is run periodically over the
life of the project to provide a continuing check on the condi-
tion of the pipeline.
Another procedure is to check pipeline wear with spools.
These are usually short pipe nipples (~30 cm long) flanged into
the pipeline downstream of the first few pump stations where
corrosion is apt to be the most extreme. The spools are removed
when the line has been drained during a planned shutdown and
cleaned, weighed and miked for average and local wear respective-
ly. Corrosion meters, consisting of probes inserted through the
pipe-wall, are also used with fair success.
Thompson and Aude (93) have summarized in detail the pro-
cess, design and construction, and operation of a long-distance
slurry pipeline. Their guidelines are reproduced with some minor
modifications in Appendix C.
Figures 11, 12, and 13 show the preparation plant facility
and the first booster pump station (Gray Mountain) of the Black
Mesa coal slurry pipeline. The preparation plant includes the
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Figure 11. Black Mesa coal slurry preparation facility,
Figure 12. Aerial view of Gray Mountain pump station,
-------
Figure 13. Interior view of Gray Mountain Pump Station
coal storage yard, water storage tank, conveyors, weighing build-
ing, crushing and grinding building, slurry mix tanks, and test
loop. The Gray Mountain pump station consists of the main pump
house, water storage pond for emergency pipeline flushing (the
small building is the water pump house), and emergency slurry
dump pond. Note the small amount of coal being reclaimed from
impoundment area. The interior of the pump house shows a bank
of positive displacement piston pumps. When visited in June
1977, the pump station was remarkably clean with no visable signs
of coal slurry anywhere.
In summary, the operation and maintenance of a coal slurry
pipeline are more complex than, but similar to, the operation of
an oil or gas pipeline. Although there are some potential envir-
onmental impacts associated with the operation of a coal slurry
pipeline, they would be less than the impacts produced by oil and
gas pipelines over the last 50 years.
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SECTION 7
EPILOGUE
This report has examined the environmental and pollution as-
pects of coal-water slurry pieplines. These have been found to
be minimal and generally not as severe as those produced by al-
ternate energy transportation modes.
Water_is truly the Achille's heel of the slurry pipeline
system. Without it/ present and proposed pipelines cannot exist.
If water were readily available as needed, coal slurry pipelines
would not be as controversial as they are. The role of water use
in the West, is multi-faceted—with legal, political, environ-
mental, and emotional implications. The major point of conten-
tion seems to be the allocation of water when it is available.
Should it serve agriculture, municipalities, industry, or energy
production and transportation?
These restraints have directed consideration of low quality
water sources such as deep saline groundwater wells and surface
wastewater (industrial and municipal sewage). Until these alter-
nate water sources become prohibitively expensive to exploit,
they will be investigated as potential water supplies.
In the future, what potential improvements may be forth-
coming to reduce the amount of water required for a coal slurry
pipeline? The first step, perhaps, would be to increase the so-
lids concentration beyond' 50% by weight. In terms of specific
power (kw-hr/tonne-km) the lowest value optimizes operating
costs, provided a minimum operating velocity is maintained to
prevent solids deposition. If the concentration is increased,
the headless requirement to overcome pipewall friction increases
also. For a given screen size distribution there is an optimum
solids concentration. As discussed by the author elsewhere (94) ,
there is in fact, an optimum coal particle size distribution for
the entire slurry pipeline system. However, there is no strong
evidence that suggests much higher solids concentrations are
Achievable for coal-water slurries to provide economical long-
distance transportation by pipeline. The hydrophobic tendencies
of most coals are believed to be at least partially responsible
for this.
The next logical step is to alter the slurry structure arti-
77
-------
ficially with chemicals, causing an effective decrease in slurry
viscosity for the same solids concentration and size distribu-
tion, or, conversely, permitting an increase in solids concentra-
tion for the same pressure drop. A few additives have been found
to reduce slightly the viscosity of coal-water slurries, but none
has been found cost effective to date. Work continues in this
area but success appears limited.
There are several advantages to be gained by increasing
solids concentration. The quantity of water is reduced, leading
to higher solids concentrations and higher headlosses for pipe-
line transport but reducing dewatering costs. In addition, the
efficiency of the power plant is increased from the reduced mois-
ture content of the coal. The savings accrued by the reduced
water must, of course, be included in the economic balance.
The ultimate goal of coal slurry pipeline transportation
should be direct combustion at the power plant. It seems folly
to add water to coal for no other purpose but transportation and
then to remove the same water from the coal to permit combustion.
Most coals are hydrophobic and do not mix well with water. Once
mixed and pipelined, complete separation is impractical with ex-
isting technology. There are enough fines (<50ym) and the speci-
fic gravity of the coal is close enough to that of water so that
conventional dewatering techniques must include costly thermal
drying to remove enough water to allow efficient combustion.
As mentioned previously, direct combustion was tried in 1961
using cyclone burners at the Jersey Central Power and Light Com-
pany (95). Slurry was obtained from the Cadiz pipeline. The
burns .were considered successful, but apparently the stack emis-
sions would not meet present day air pollution standards, speci-
fically nitrous oxide levels.
Perhaps if water becomes too scarce and/or costly, the tech-
nology of direct combustion will be re-examined. A compromise of
first stage rough dewatering with a higher pipelined solids con-
centration or a coarser size distribution may be possible.
ENERGY SLURRIES OF THE FUTURE
If direct combustion looks desirable and feasible in the in-
termediate future, the logical extension of this thinking for the
long term is to consider a total energy slurry-coal delivered in
a hydrocarbon liquid carrier. The carrier could be crude oil,
synthetic crude oil (Syncrude), or a member of the alcohol fam-
ily such as methanol.
Crude oil is unlikely to be available where coal is mined.
It would have to be pipelined to the coal source and mixed there
for slurry transport to market. Possible customers would be
78
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utility plants, which are presently burning oil and which must
convert to coal as oil supplies dwindle or become excessively ex-
pensive. Retrofitting of oil burners to coal-oil slurry burners
may be justifiable economically instead of total conversion to
coal. Alaskan crude oil and Montana coal or Dakota lignite might
be potential candidates for future consideration. Some proprie-
tary research is investigating the separation of coal and oil at
the terminus of a pipeline, but previous research (96) suggests
this may be expensive. Therefore, direct combustion of the to-
tal slurry may be the best approach.
The concept of the creation of a liquid hydrocarbon carrier
from coal at the mine site is appealing, provided more water is
not used in the process than that required by a coal-water slurry
pipeline. The economics of liquifaction are poorly understood
pending further research. Consequently, the economics of produc-
ing a liquid hydrocarbon, such as synthetic oil or methanol, are
vague. However, some preliminary work which appears encouraging
has been done:
1. Wentworth Bros, proposes to build a lignite-to-methanol con-
version plant in North Dakota. The methanol would be pipe-
lined to the Lakehead for shipment via the Great Lakes or
rail spur for eventual use as a turbine fuel to drive gener-
ators (97) .
2. L. Keller, president of Methacoal Corp. of Dallas, Texas, has
patented a process in which methanol is made from coal and
used as a carrier for coal in pipeline transportation. The
coal and methanol may be separated for various uses or burned
directly in a boiler. Methacoal is claimed to be hydrauli-
cally stable (no solids deposition, even for laminar flow,
inexpensive to produce, non-consuming of water, and more eco-
nomical than low-sulfur crude oil (40) .
3. Banks and Horton (98) have examined efficiency improvements
in pipeline transportation systems and have recommended re-
search and development for eight systems, two of which in-
volve methanol-coal slurries.
Transport Energy Ratio
When pipeline transportation of fossil fuels is involved,
the transport energy ratio may be defined as the ratio of energy
required for transport to the total usable energy delivered. In
terms of energy slurries this can be simplified to the ratio of
energy requirement for overcoming pipewall frictional resistance
to the calorific content of the slurry transported. Thus, a com-
mon assumption inferred is that pump motor efficiences, elevation
differences, and minor losses are essentially constant regardless
of the slurry and are therefore ignored. Another assumption is
that the market use in each case will be combustion of fossil-
derived fuels in thermal electric generating stations. While the
water that is separated from a coal-water slurry is used for
79
-------
cooling purposes, it has no input energy value for combustion.
The transport energy ratio is
specific power x throughput of combustibles
calorific content delivered
kw-hr tonnes hr _ kw-hr
X
tonne-km hr Joules Joule-km
where tonnes refers to the mass of combustible solids and liq-
uids. The specific power is the power required to overcome pipe-
wall resistance in delivering one tonne of combustibles per hour
a distance of one kilometer. The smaller the transport energy
ratio, the more efficient the energy slurry for pipeline trans-
portation.
Table 17 compares the transport energy ratios (kw-hr/Joule-
km) for three energy slurries tested by the author. Water is al-
so included to round out the comparison because it has zero ener-
gy efficiency. The slurries tested were a Black Mesa type of
coal (similar in size distribution to that of Black Mesa) in
water and a Utah coal both in No. 2 fuel oil and in commercially
available methanol. The coal properties varied and are listed in
the table. The chief difference was particle size distribution.
The Utah coal was significantly finer than the Black Mesa type of
coal. The power requirements for pipeline transport were esti-
mated from rheological data taken in the Colorado School of Mines
Rheology Lab. Scale-up headloss equations verified from field
operations with numerous mineral slurries were applied to the en-
ergy slurries.
Operating conditions at the Black Mesa coal slurry pipeline
were used as the standard. Table 17 estimates the transport en-
ergy ratios for the energy slurries,if transported under similar
flow conditions in the Black Mesa pipeline.
Several interesting observations can be made from the com-
parison. The range of transport energy ratios varied from about
one-half to in excess of two. While a minimum ratio is desir-
able, it is obvious from the data that this is achieved by in-
creasing the weight concentration of the solid or liquid phase
with the higher calorific content. Because the alternate fuels
(oil and alcohol) are more valuable than coal, it is apparent
that the choice of energy slurry for transport must be optimized
in conjunction with its preparation. The availability or pro--
cessing of the higher-priced carrier liquid will be critical.
If the oil or alcohol is converted directly from coal, it is pro-
bable that processing economics will dictate a high coal/low li-
quid carrier mixture.
For combustion purposes no dewatering costs will be incurred,
so effectively this cost can be transferred to the head end of
80
-------
TABLE 17. COMPARISON. OF ENERGY SLURRIES*
oo
Slurry
Water
Black
Mesa
coal in
water
Utah
coal in
methan-
ol
Utah
coal
in #2
oil
C %+
Cw'%
0
46.9
63.7
54.6
45.0
55.0
65.0
Sp.gr av.
mix
1.000
1.172
1.105
1.046
1.027
1.083
1.144
Tonne s/hr*
dry coal
0
539.
692.
561.
453.
584.
730.
5
0
0
8
5
2
Tonne s/hr
liquid
981
611
394
467
554
478
393
.8
.4
.7
.0
.7
.3
.2
Tonnes/hr
total
981
1150
1086
1028
1008
1062
1123
.8 46
.9 71
.7 174
.0 114
.5 71
.8 104
.4 226
kPa§
km
.525
.791
.279
.018
.649
.254
.996
Specific
power
kw-hr/#
tonne -km
0.0129
0.0364
0.0439
0.0304
0.0195
0.0269
0.0553
Energy
ratio**
kw-hr/
I09joule-km
2.140
1.469
1.109
0.472
0.647
1.442
*Flow conditions: Velocity=l.75m/s; I.D.=446.1mm; pipe roughness=0.046mm;
temperature=30C; elevation gradients and pump-motor efficiencies
excluded.
Assumed calorific content: Black Mesa type coal-28.6
(106Joules/kg)
Weighted mean particle size:
Utah coal-27,9
: Black Mesa type coal:
0.308mm
Specific gravity=1.456
w
Liquid specific gravity:
= concentration of dry solids by weight
Methanol=0.791; #2 Oil=0.835
Methanol-19.7
#2 Oil-44.7
Utah coal:
0.058mm.
specific gra-
vity=1.429
^tonnes/hr = metric tonnes per hour transported
§kPa/km = pressure drop to overcome pipewall friction in kiloPascals/km
#kw-hr/tonne-km = specific power for pipeline transport in kw per tonne per hour of
combustibles per km of horizontal distance.
**kw-hr/109Joule-km = energy transport ratio = specific power required to overcome
pipewall resistance in delivering 109 Joules a distance of 1 km.
-------
the pipeline for grinding the coal to a finer size. Since pul-
verization of coal to about 85% minus 75 microns is necessary
for power plant combustion, this grinding cost is not attribut-
able to pipeline transportation. The finely ground coal allows
high stable slurry concentrations to be produced, thus minimiz-
ing the amount of carrier liquid. Also, the affinity that coal
has for hydrocarbon liquids enables easier slurry mixing, avoid-
ing the often-encountered hydrophobic tendencies of coal in water.
The disadvantage of this process, is that if the coal is
ground so finely, the slurry becomes paste-like with a high vis-
cosity and high energy requirement for pipelining. However, the
elimination of dewatering costs means that additional costs can
be absorbed by increased pipeline transportation costs.
Preliminary work suggests a strong potential for energy
slurries to become an alternate power plant fuel of the future.
If burned directly, this fuel, besides being higher in calorific
value, would probably ameliorate the materials handling problems
associated with railroad-delivered or coal-water slurry coal.
It is strongly recommended that coal-liquid hydrocarbon slurries
be researched at the preparation stage, pipeline transportation
stage, and combustion stage to evaluate their economics.
Because energy slurries are combustible, their transporta-
tion by pipeline would probably present the same environmental
and pollution consequences as oil pipelines.
82
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90
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APPENDIX A
MAJOR PIPELINE INSTALLATIONS
SUMMARY OF MAJOR PIPELINE INSTALLATIONS
SPECIFIC
SLURRY GRAV. OF
CODE
ASH-T
ASH-T
CO-C
CO-C
CO-C
CO-C
CO-C
ro-r
u w w
co-o
co-o
fMI— P
OU L>
cu-c
cu-c
cu-c
cu-c
cu-c
cu-c
cu-c
CU-T
CU-T
CU-T
CU-T
CU-T
CU-T
CU-T
FE-C
FE-C
FE-C
FE-C
FE-C
FE-C
FE-C
FE-C
Ff-r.
LOCATION OWNER SOLIDS
SUNBURY PA PA. POWER 4 LIGHT
SAFE HARBOR PA PA. POWER 4 LIGHT
CONSOLIDATION
BLACK MESA, AZ. USA
CADIZ, OH USA HANNA COAL CO
PA. POWER 4 L IGHT
CHESNICK.PA.USA HANNA COAL CO
POI AMP,
r \J\^f\nU
ROBINSON RUN MINE WV A .USACONSOL 1 DATED COAL CO
LOVERIDGE.W. VIRGINIA USACONSOL 1 DATED COAL CO
KRI TIIBtfPV
I\Q 1 1 Urxfv C T
BOUGAINV ILLE
ARBITER PLANT, USA
WEST IRAN
PINTO VALLEY, USA
ELSO-LIANTA, CHILE ANACONDA
HAYDEN.AZ.USA KENNECOTT COPPER CO
IDSA.FREEPORT-WIRAN
JAPAN
WHITE PINE, Ml, USA WHITE PINE COPPER
BUTTE.MT.USA ANACONDA
W . V 1 RG 1 N 1 A
W . V 1 RG 1 N 1 A
CANADA U.S. BORAX
MONTANA, USA ANACONDA
WAIPPI (LAND)
WAIPPKOFFSHORF.)
CHONGIN.N. KOREA
SAVAGE RIVER, TASMANIA
PENA, COL OR ADA-MEXICO
SIERRA GRANDE, AGTA
LAS TRUCHAS, MEXICO
SAMARCO, BRAZIL
CANADA ANACONDA
2
2
-
1
1
1
-
-
4
2
1
1
1
2
-
-
5
5
5
5
5
~
.25
.4
—
.4
.85
.5
--
—
.2
.7
.2
.4
.4
.6
--
--
.0
.0
.0
.0
.0
..
DIAMETER
IN CONC VEL
MM WT. M/S
254.
152.
2.54
457.
273.
323.
152.
9 *iA
Z J *t •
254.
504.
1 9 "7
1 £. 1 *
152.
101 .
101 .
101 .
152.
152.
101 .
304.
587.
508.
101 .
102.
127.
508.
203.
304.
228.
203.
203.
203.
508.
...
0 10. 0 4.39
4 17.0 1.62
2
0 50.0 1.52
8
4 52.5 2.44
0_ —
— W — •• —
0 38.0 4.27
e —
0_— - - --
•• ™* ~ ••
4
6
6
6
4
4 26.0 1.22
6 _u_
8
3 17.5 3.22
0
6
t
0
o
2
8
__-
6
2
2
2
o
- -- _ --
CAPACITY
L TONNES
INITIAL PUMP
KM PER YEAR OPERATION TYPE
2.408
1.372
1.18
4.53
173.8
0.792
.925 60.0
* -- n Q i
u * y 1
0.91
0.18
0.27
0.36
727.3*
0.853
831.8-
0.5
1.897
25454. 5«PP
18181.8*
0.91
0.91
98.17 4.1
85.30 2.3
48.28 1.6
27.36 1.9
402.3 1.4
27.36 10.9
— 2.iF+r>fi
• 956
1953
1957
1970
1957
1953
1957
1978
»972
1974
1972
1974
1959
1958
1973
1963
1953
1957
1957
1957
»964
1971
1971
1975
1967
1974
1974
1975
1977
CSE
CSE
DAPI
DAPI
DAPI
C
C
C
C
VPL
VPL
PL
CSE
DAPI
C
CSE
C
C
C
C
C
C
PL
C
PL
PL
PL
_
2
2
2
-
-
3
3
3
-
-
2
-
-
.
-
-
-
-
3
.
3
3
3
TOTAL
9
9
13
6
8
6
4
2
3
3
14
-------
SUMMARY OF MAJOR PIPELINE INSTALLATIONS
SLURRY
CODE LOCATION
FE-C LABRADOR-PT.MARMITE.CAND
OWNER
SPECIFIC
GRAV. OF
SOLIDS
DIAMETER
IN CONC
MM WT.
203.2
VEL
M/S
L
KM
CAPACITY
TONNES
PER YEAR
10.9
INITIAL PUMP
OPERATION TYPE
1974 -
PUMP
/STA
TOTAL
PUMPS REF.
FE-T HUNNER PLANT
FE-T STAR LAKE,NY,USA
FE-T CALUMET,MN,USA
FE-T CANISTEO.MN.USA
FE-T GRAND RAPIDS,MN,USA
FE-T HI8BING.MN.USA
FE-T MINNESOTA,USA
FE-T KEEWATIN.MN.USA
FE-T SELLWOOD,ONTARIO,CAND
FE-T MORGANTOWN,PA,USA
FE-T CALUMET,MN,USA
FE-T GEORGIA,USA
M.A. HANNA
LAUGHLIN STEEL
LAUGHLIN STEEL
CLEVELAND CLIFFS
LAUGHLIN STEEL
M.A. HANNA
M.A. HANNA
LOWPHOS ORE,LTD
BETHLEHAM CORNWALL
LAUGHLIN STEEL
PHILIPP CORP.
3.2
2.7
2.8
2.8
3.0
3.2
3.4
3.0
2.8
3.0
3.0
2.58
406.4
298.5
406.4
457.2
609.6
488.9
406.4
292.1
355.6
254.0
609.6
203.2
16.0
20.0
14.8
17.5
9.5
11 .0
--.
...
4.0
35.0
6.0
...
2.92
3.66
2.56
2.68
2.65
2.20
...
3.20
2.10
2.40
5.364
1 .524
2.621
0.783
1 .633
3.962
0.488
2.663
1 .737
...
...
179.1*PP
2H.8*
5636.4-
__•_
...
»955
1957
1958
1958
1959
1959
1955
....
»957
1958
1961
1951
C
C
C
C
C
C
C
C
C
C
CPA
C
8
14
»
2
2
2
5
6
4
2
2
GIL-0 UTAH-COLORADO
AMER. GILSONITE CO 1 .04
152.4
46.0
t.19
115.9
0.36
1957 PL
10
GS-TO LORRAINE MINE-FREDDIE NORLORRAINE GOLD MINES 2.7
228.6 50.0 t.33
9.449 57272.7+ J963 C
8 »
G-T CREIGHTON.PA
PITSBG. PLATE GLASS 2.5
101.6 31.0 1.95
1.707
1949 C
12 »
HM-C FLORIDA,USA
HM-C AUSTRALIA
HM-C LAWTEY FL.USA
KC-0 GEORGIA,USA
KC-0 GEORGIA,USA
KC-0 GEORGIA,USA
PHILLIPP CORP.
PHILLIPP CORP.
PHILLIPP CORP.
3.4 101.6
1.3 152.4
3.4 101.6
2.6 203.2 25.0 1.22
2.6 203.2 33.0 1.22
2.6 304.8 25.0 1.22
17.70
25.75
8.047
40.9°
7 f R e
C. I . O
...
...
1955
1955
195.1
1959
1940
C
C
C
C
C
2
16
2 \
3 »
2 1
LI-0 CALAVERAS
LI-0 RUGBY,ENGLAND
LI-0 TRINIDAD
LI-0 COLUMBIA
177.8
254.0
203.2
177.8
1.4 1971 DAPI 2
1.5 1964 OAPI 2
0.5 1959 DAPI 2
0.36 1944
-------
SUMMARY OF MAJOR PIPELINE INSTALLATIONS
SLURRY
CODE
LOCATION
OWNER
SPECIFIC
GRAV. OF
SOLIDS
DIAMETER
IN CONC
MM WT.
VEL
M/S
L
KM
CAPACITY
TONNES
PER YEAR
INITIAL PUMP
OPERATION TYPE
/STA
TOTAL
PUMPS REF.
MIL-T CANADA
330.2
9090.9*
NI-C CANADA
203.2
1818.2*
NI-T WEST MINNESOTA.USA
101 .6
9.1E-02
J970 - -
CO
PHM-0 BARTOW.FL.USAARMOUR AGRICULTURAL CHEMICAL CO
PHM-0 FLORIDA,USA SMITH-DOUGLAS CO INC
PHM-0 NORALYN MINE,FL.USA
PHM-0 NORALYN MINE.FL.USA
PHM-0 NICHOLS FL.USA
PHM-0 LEE CREEK,NC,USA
PHM-0 WHJTE SPRINGS FL.USA
PHM-0 BONNY LAKE MINE
PHM-0 FORT MEAOE,FL.USA
PHM-0 TAPtRA-UBERABA,BRZL
PHM-0 ACHANSNORALYN MlNE,FL,USAINT. MIN 4 CHEM CO.
PHM-0 SYDNEY MINE FL.USA AMER. CYANAMID CO.
PHM-0 TENOROC MINE FL.USA SMITH-DOUGLAS CO (NC
PHM-0 COLUMBIA MONSANTO CHEM. CO.
MOBIL CHEMICAL CO.
TEXASGULF
OCCIDENTAL CHEM. CO.
W.R.GRACE
USS AGRICHEM. CO.
2.75
2.7
2.6
2.6
2.7
2.7
2.6
2.65
3.2
2.7
2.65
2.7
406.4
406.4
457.2
508.0
457.2
457.2
508.0
457. 2
508.0
244.5
508.0
406.4
406.4
254.0
25.0
25.0
35.0
35.0
35.0
35.0
37.0
32.5
30.0
...
40.0
35.0
35.0
25.0
3.658
3.658
5.029
5.029
3.658
3.322
5.090
4.572
4.724
___
3*658
3.627
3.962
3.719
3.200
3.200
7.62
7.62
2.743
4.420
5.273
8.230
3.658
...
6.437
6.096
3.962
0.137
...
...
...
...
...
...
...
...
...
...
...
---
1955
1960
1974
1974
1971
1966
1965
1946
1968
1978
1949
1960
C
C
C
C
C
C
C
C
GIW
REPL
C
C
C
3 -
4
4
7
7
4
5
4
10
4
3
14
10
4
2
2
2
2
2
2
2
1
1
1
PHP-0 CONDA.ID.USA JR. SIMPLOT CO. 2.95 127.0 50.0 5.014 2.295
PHP-0 CONDA.ID.USA JR. SIMPLOT CO. 2.95 203.2 50.0 5.014 2.295
PHP-0 SYDNEY MINE FL.USA AMER. CYANAMI0 CO. 2.65 406.4 35.0 3.63 6.096
PHP-0 ACHANSNORALYN MINE FL.USAINT. MIN & CHEM CO. 2.7 508.0 40.0 3.66 6.437
C
C
1949 CSE
C
I 2
1 2
10 1
14 I
PHO-T MATON,INDIA
PHO-T FLORIDA.USA
PHO-T FLORIDA,USA
PHO-T
PHO-T SULLIVAN MONTANA
PHO-T NICHOLS,FL,USA
PHO-T NICHOLS,FL.USA
PHO-T CAPE PROV..SAFRICA
PHO-T WHITE SPRINGS,FL.USA
HINDUSTAN IN LTD.
CHEMICAL CO.
CHEMICAL CO.
PA. POWFR 4 LIGHT
MERAMEC MlNING CO.
VI-CAROL CHEM. CORP.
VI-CAROL CHEM. CORP.
CHEMFOS LTD.
OCCIDENTAL CHEM CO.
2.8
2.6
2.6
2.1
4.2
2.65
2.65
2.6
2.72
127.0
406.4
355.6
254.0
101 .6
355.6
406.4
152.4
508.0
40.0
...
...
5.0
5.0
5.0
0.0
5.0
0.488
...
...
2.896
4.237
1.890
5.243
1.500
...
0.274
7.724
6.287
3.060
2.967
1976 WSP
1959 C
1952 C
1953 C
1964 CRU
1952 C
1958 C
1965 C
1965 C
2
5
7
2
7
5
18
3
-------
SUMMARY OF MAJOR PIPELINE INSTALLATIONS
SLURRY
CODE LOCATION
PHO-T KIMGSFORO MN-FL.USA
OWNER
SPECIFIC
GRAV. OF
SOLIDS
INT. MIN & CHEM. CO. 2.65
DIAMETER
I N CONG
MM WT.
457.2
2.0
VEL
M/S
4.511
L
KM
4.267
CAPACITY
TONNES
PER YEAR
INITIAL PUMP
OPERATION TYPE
1975 C
PUMP
/STA
TOTAL
PUMPS REF.
PY-C GMCL.SAFRICA
3.0
127.0
181.8«
SI-T BLACKBIRD,ID,USA
SI-T BRALORNE.BC
SI-T KELLOGG,ID,USA
SI-T BUNKER HILL,USA
CALERA MINING CO. 2.7 152.4 5.0
BRALORNE PIONEER Ml 2.7 76.2 8.0
2.75 127.0 0.0
».46 127.0
1.387 2.262
1.646 1.341
1.661 2.865
38.2"
1946 C
1960 C
1961 C
CSE
18
3
4
6
SR-T
SR-T SUNBRIGHT.VA.USA
MINES IN JAPAN
FOOTE MINERAL CO.
I .57
1 .8
318.8
101.6
0.0
1.158 0.366
36363.6+
1968
1952
DARE - -
C - -
VO
SS-T THOMPSON,MANITOBA,CAND INT. NICKEL
3.5
127.0
5.0
3.658 0.3048
1959 C
UP-C UNION S. AFRICA
UP-C DAGGAFONTEIN UNION SAFC
UP-C DAGGAFONTEIN UNION SAFC
ANG-TRS-CON-INV CO.
3.0
3.0
3.0
127.0
101 .6
127.0
1 .0
1.372 5.224
2.853
1.356 2.853
1963 C
1963 C
1963 C
UR-TO
UR-TO
UR-TO
UR-TO
UR-TO
UR-TO
UR-TO
UR-TO
UR-TO
UR-TO
EAST CHAMP D. OR.RSA
BABROSCO.RSA GEN MIN & F 1 NA CORP
FREDOIE-N-S.RSA FREDDIES CONSOL. Ml
FREDDIE S-WELSOM.RSA FREDDIES CONSOL. Ml
PRES. STEYN-WELCOM.RSAPRES STEYN GOL MIN CO
PRES. BRAND-RES. STEYNPRES BRAND GOL MfN CO
PRES. BRAND- SAAI PLAAS.GMCL
DOORFONTEIN.RSANEW CONSOL. GO FIELD LTD
ELLATON-STILFONTEIN.RSAGEN MIN & FINA CORP.
S. AFRICA CO. SUR VAAL REEFS
2
2
2
2
2
2
2
2
2
1
.7
.7
.7
.7
.7
.7
.7
.7
.7
.28
152
152
304
406
228
254
228
215
228
--
.4
.4
.7
.4
.6
.0
.6
.9
.6
-
--
0.0
0.0
0.0
0.0
0.0
--
0.0
0.0
--
...
0.972
1 .1 52
1 .207
1.128
1.384
___
0.872
1.027
...
...
19.00
8.138
1 1.23
6.401
3.673
--_
10.67
15.26
...
...
...
...
___
___
...
45300+
40000+
2.667+
22727.3+
1963
1963
1963
1963
1963
1963
1963
196.3
1963
....
C
PL
CSE
CSE
C
C
CSE
CSE
REPL
DARE
4
2
4
6
6
4
5
6
6
4
-------
TABLE B-l.
APPENDIX B
WATER QUALITY STANDARDS
DISSOLVED SOLIDS IN POTABLE WATER(Ref. 60)
(A Classification Based Upon Relative Abun-
dance of Dissolved Solids)
Major constituents(1.0 to 100 ppm):
Sodium Bicarbonate
Calcium Sulfate
Magnesium Chloride
Silica
Secondary constituents(0.01 to 10.0 ppm) :
Iron Carbonate
Strontium Nitrate
Potassium Fluoride
Boron
Minor constituents(0.0001 to 0.1 ppm):
Antimony*
Aluminum
Arsenic
Barium
Bromide
Cadmium*
Chromium*
Cobalt
Copper
Germanium*
Iodide
Lead
Lithium
Manganese
Molybdenum
Nickel
Phosphate
Rubidium*
Selenium
Titanium*
Uranium
Vanadium
Zinc
Trace constituents(generally less than 0.001 ppm):
Beryllium Ruthenium*
Bismuth Scandium*
Cerium* Silver
Cesium Thallium*
Gallium Thorium*
Gold Tin
Indium Tungsten*
Lanthanium Ytterbium
Niobium* Yttrium*
Platinum Zirconium*
^ Radium - L —
*Elements marked with an asterisk occupy an uncertain position
in the list.
95
-------
TABLE B-2.
MAJOR CHEMICAL CONSTITUENTS IN WATER-THEIR SOURCES,
CONCENTRATIONS, AND EFFECTS UPON USABILITY(Ref.60)
Constituent Major Sources
Concentration in Effect upon usabil-
natural water ity of water
Silica
(Sio2)
Iron
(Fe)
Feldspars,ferro-
magnesium and
clay minerals,
amorphous sili-
ca chert,opal.
Ranges generally
from 1.0 to 30
ppm, although as
much as 100 ppm
is fairly com-
mon; as much as
4000 ppm is
found in brines.
Natural sources: Generally less
Igneous rocks: than 0.50 ppm in
Amphiboles, fer- fully aerated
ro-magnesium mi- water. Ground
cas , ferrous
sulfide(FeS) ,
ferric sulfide
or iron pyrite
(FeS) , magne-
Sandstone rocks :
Oxides , carbon-
ates, and sul-
fides or iron
clay minerals.
Manmade sources :
Well casing, pip-
ing , pump parts ,
storage tanks,
and other objects
of cast iron and
steel which may be
in contact with
the water.
Industrial wastes .
water having a
pH less than 8.0
may contain 10
ppm; rarely as
much as 50 ppm
may occur. Acid
water from ther-
mal springs,mine
wastes, and in-
dustrial wastes
may contain more
than 6,000 ppm.
In the presence of
calcium and magnes-
ium, silica forms
a scale in boilers
and on steam tur-
bines that retards
heat; the scale is
difficult to re-
move. Silica may be
added to soft water
to inhibit corros-
ion of iron pipes.
More than 0.1 ppm
precipitates after
exposure to air;
causes turbidity,
stains plumbing
fixtures, laundry
and cooking uten-
sils and imparts
objectional tastes
and colors to foods
and drinks. More
than 0.2 ppm is ob-
jectionable for
most industrial
uses.
cont'd
96
-------
TABLE B-2 (continued)
Constituent Major Sources
Concentration in
natural water
Effect upon usabil-
ity of. water
Generally 0.20
ppm or less.
Ground water may
contain more
than 10 ppm. Re-
servoir water
that has "turned
over" may con-
tain more than
150 ppm.
Manganese Manganese in na-
(Mn) tural water pro-
bably comes most
often from soils
and sediments.
Metamorphic and
sedimentary
rocks and mica
biotite and am-
phibole horn-
blende minerals
also contain
large amounts
of manganese.
Calcium Amphiboles,feld- As much as 600
(Ca) spars, gypsum, ppm in some wes-
pyroxenes, ara- tern streams;
gonite, calcite, brines may con-
dolomite , clay tain as much as
minerals. 75,000 ppm.
Magnesium
(Mg)
Amphiboles,
olivine, pyrox-
enes, dolomite,
magnesite, clay
minerals.
As much as sev-
eral hundred
parts per mil-
lion in some
western streams;
ocean water con-
tains more than
1,000 ppm, and
brines may con-
tain as much as
57,000 ppm.
Sodium
(Na)
Feldspars (al-
bite); clay min-
erals ,evaporites
such as halite
(Nad) and mira-
bilite.
As much as 1,000
ppm in some west-
ern streams, a-
bout 10,000 ppm
in sea water; a-
bout 25,000 ppm
in brines.
More than 0.2 ppm
precipitates upon
oxidation; causes
undesirable tastes,
deposits on foods
during cooking,
stains plumbing
fixtures and laun-
dry, and fosters
growths in reser-
voirs, filters, and
distribution sys-
tems. Most indust-
rial users object
to water containing
more than 0.2 ppm.
Calcium and magnes-
ium combine with
bicarbonate, car-
bonate, sulfate and
silica to form heat
retarding, pipe-
clogging scale in
boilers and in
other heat-exchange
equipment. Calcium
and magnesium com-
bine with ions of
fatty acid in soaps
to form soap suds;
the more calcium
and magnesium, the
more soap required
to form suds. A
high concentration
of magnesium has a
laxative effect,
especially on new
users of the supply
More than SOppm so-
dium and potassium
in the presence of
suspended matter
causes foaming,
which accelerates
(cont'd)
97
-------
TABLE B-2 (continued)
Constituent Major Sources Concentration in
natural water
Effect upon usabil-
ity of water
(Na2S04-10H20);
industrial wastes.
Potassium
(K)
Feldspars(ortho- Generally less
clase and micro- than about 10
cline),feldspa- ppm;as much as
thoids, some mi- 100 ppm in hot
cas, clay miner- springs; as
als. much as 25,000
ppm in brines.
Carbonate
(C03)
Limestone,
dolomite
Bicarbonate Limestone,
(HC03) dolomite
Sulfate
(S04)
Oxidation of
sulfide ores;
gypsum; anhy-
drite; indus-
trial wastes.
Commonly 0 ppm
in surface water;
commonly less
than 10 ppm in
ground water.
Water high in
sodium may con-
tain as much as
50 ppm of carbon-
ate.
Commonly less
than 500 ppm;
may exceed 1,000
ppm in water
highly charged
with carbon
dioxide.
Commonly less
than 1,000 ppm
except in streams
and wells influ-
enced by acid
mine drainage.
As much as 200,
000 ppm in some
brines.
scale formation and
corrosion in boil-
ers . Sodium and po-
tassium carbonate
in recirculating
cooling water can
cause deterioration
of wood in cooling
towers. More than
65 ppm of sodium
can cause problems
in ice manufacture.
Upon heating bicar-
bonate is changed
into steam, carbon
dioxide, and car-
bonate combines
with alkaline
earths-principally
calcium and magnes-
ium- to form a
crustlike scale of
calcium carbonate
that retards flow
of heat through
pipe walls and re-
stricts flow of
fluids in pipes.
Water containing
large amounts of
bicarbonate and
alkalinity are un-
desirable in many
industries.
Sulfate combines
with calcium to
form an adherent,
heat-retarding
scale. More than
250 ppm is object-
ionable in water in
some industries.
Water containing
about 500 ppm of
sulfate tastes
(cont'd)
98
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TABLE B-2 (continued)
ConstituentMajor sourcesConcentration in
natural water
Effect upon usabil-
ity of water
Chloride
(CD
Chief source
is sedimentary
rock(evapor-
ites): minor
sources are ig-
neous rocks.
Ocean tides
force salty
water upstream
in tidal estu-
aries.
Flouride
(F)
Amphiboles
(hornblende),
apatite, flu-
rite, mica.
Commonly less
than 10 ppm in
humid regions;
tidal streams
contain increas-
ing amounts of
chloride (as much
as 19,000 ppm) as
the bay or ocean
is approached. A-
bout 19,300 ppm
in sea water, and
as much as 200,
000 ppm in some
brines.
Concentrations
generally do not
exceed 10 ppm in
ground water or
1.0 ppm in sur-
face water. Con-
centrations may
be as much as
1,600 ppm in
brines.
bitter; water con-
taining about 1,000
ppm may be cathar-
tic.
Chloride in excess
of 100 ppm imparts
a salty taste. Con-
centrations greatly
in excess of 100
ppm may cause phys-
iological damage.
Food processing in-
dustries-textile
processing, paper
manufacturing, and
synthetic rubber
manufacturing-
desire less than
100 ppm.
Flouride concentra-
tion between 0.6
and 1.7 ppm in
drinking water has
a beneficial effect
on the structure
and resistance to
decay of children's
teeth. Fluoride in
excess of 1.5 ppm
in some areas
causes "mottled e-
namel" in child"-
ren's teeth. Flour-
ide in excess of
6.0 ppm causes pro-
nounced mottling
and disfiguration
of teeth.
(cont'd)
99
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TABLE B-2 (continued)
Constituent Major Sources Concentration in
Natural Water
Effect on usabil-
ity of water
Nitrate
(N03)
Atmosphere; le-
gumes , plant de-
bris, animal ex-
crement, nitro
geneous fertiliz-
er in soil and
sewage.
Dissolved
solids
The mineral
constituents
dissolved in
water consti
tute the dis-
solved solids.
In surface water
not subjected to
pollution, con-
centration of ni-
•trate may be as
much as 5.0 ppm
but is commonly
less than 1.0
ppm. In ground
water the con-
centration of
nitrate may be
as much as
1,000 ppm.
Surface water
commonly contains
less than 3,000
ppm; streams
draining salt
beds in arid re-
gions may con-
tain in excess
of 15,000 ppm;
some brines con-
tain as much as
300,000 ppm.
Water containing
large amount of
nitrate (more than
100 ppm) is bitter
tasting and may
cause physiological
distress. Water
from shallow wells
containing more
than 45 ppm has
been reported to
cause methemoglobi-
nemia in infants.
Small amounts of
nitrate help reduce
cracking of high
pressure boiler
steel.
More than 500 ppm
is undesirable for
drinking and many
industrial uses.
Less than 300 ppm
is desirable for
dyeing of textiles
and the manufacture
of plastics, pulp
paper, rayon. Dis-
solved solids
cause foaming in
steam boilers; the
maximum permissible
content decreases
with increases in
operating pressure.
100
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TABLE B-3. DRINKING WATER STANDARDS OF THE
U.S. PUBLIC HEALTH SERVICE
(Ref.60), General Constituents
Recommended limits Mandatory limit's
of concentrations on concentrations
Substance in mg/1 in mg/1
Alkyl benzene sulfonate(ABS) 0.5
Arsenic(As) 0.01 0.05
Barium(Ba) - 1.0
Cadmium(Cd) - 0.01
Carbon chloroform extract(CCE) 0.2
Chloride(Cl) 6 250
Chromium(hexavalent)(Cr+ ) - 0.05
Copper(Cu) 1.0
Cyanide(CN) 0.01 0.2
Fluoride(F) t t
Iron(Fe) 0.3
Lead(Pb) - 0.05
Manganese(Mn) 0.05
Nitrate(N03)* 45
Phenols 0.001
Selenium(Se) - °-01
Silver(Ag) - °-05
Sulfate(SO.) 250
Total dissolved solids(TDS) 500
Zinc(Zn) 5
*In areas in which the nitrate content of water is known to be in
excess of the listed concentration, the public should be warned
of the potential dangers of using the water for infant feeding.
*See Table B-4.
101
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TABLE B-4.
DRINKING WATER STANDARDS OF THE
U.S. PUBLIC HEALTH SERVICE
(Ref.60), Fluoride .
Annual average of maximum
daily air temperatures,
°Fahrenheit
Recommended control limits
(flouride concentrations)
mg/1
Lower Optimum
Upper
50.0-53-7
53.8-58.3
58.4-63.8
63.9-70.6
70.7-79.2
79.3-90.5
0.9
0.8
0.8
0.7
0.7
0.6
1.2
1.1
1.0
0.9
0.8
0.7
1.7
1.5
1.3
1.2
1.0
0.8
TABLE B-5.
DRINKING WATER STANDARDS OF THE
U.S. PUBLIC HEALTH SERVICE
(Ref.60), Radioactivity
Source
Recommended limits,
micromicrocuries perliter
Radium - 226
Strontium - 90
Gross beta activity
3
10
1,000
102
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TABLE B-6. STANDARDS FOR RAW WATER USED AS SOURCES
OF DOMESTIC WATER SUPPLY*
Excellent source Good source Poor source
of water supply, of water sup- of water sup-
requiring disin- ply requir- ply, requir-
Constituent fection only, ing usual ing special
as treatment. treatment or auxiliary
such as fil- treatment and
B.O.D. ( 5-day ) ppm
Monthly average 0.75
Maximum day or sample 1 . 0
Coliform MPN per 100 ml.
Monthly average 50-100
Maximum day or sample
Dissolved oxygen
ppm. average 4.0-7.5
% saturation 50-75
pH average 6.0—8.5
Chlorides, max. . .ppm. 50
Iron/Manganese. .Max. ppm. 0.3
Fluorides. .. .ppm. 1.0
Phenolic compounds
Max. ppm. none
Color.... ppm 0-20
Turbidity. . .ppm 0-10
tration and disinfection.
disinfection.
1.5-2.5 2.0-5.5
3.0-3.5 4.0-7.5
240-5,000 10,000-20,000
<20%> 5,000
< 5%>20,000
2.5-7.0 2.5-6.5
25-75
5.0-9.0 3.8-10.5
250 500
1.0 15
1.0 1.0
.005 .025
20-70 150
40-250
*Source: Reference 60,
103
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TABLE B-7. DRINKING WATER STANDARDS OF THE
WORLD HEALTH ORGANIZATION
Concentrations(mg/1)
. . WHO International(1968) WHO European(1961)
Consti- Permiss- Excessive Maximum Recommended Tolerance
tuent ible limit limit allowable limit _ limit
Ammonia(NH4) - - - 0.5
Arsenic - - 0.2 - 0.2
Cadmium - - - - 0.05
Calcium 75 200 -
Chloride 200 600 - 350
Chromium
(hexavalent) - - 0.05
Copper 1.0 1.5 - 3.0
Cyanide - - 0.01 - 0.01
Fluoride - - - 1.5
Iron 0.3 1.0 - 0.1
Lead - - 0.1 - 0.1
Magnesium 50 150 - 125
104
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APPENDIX C
GUIDELINES FOR PROCESS, DESIGN AND CONSTRUCTION,
AND OPERATION OF SLURRY PIPELINES*
I. PROCESS
A. HYDRAULICS
1. Selection of Carrying Fluid
Engineer: _Makes balance among quality, availability,
location, cost and environmental impact. Consider
wastewater as carrier.
Operator: Must monitor quality and quantity of fluid
Potential Problems: Availability may decrease over pro-
ject life. Export of water politically sensitive.
2. Selection of Optimum Size Range
Engineer: Specifies positive top size control such as
safety screens based on laboratory analysis of
material.
Operator: Must strictly enforce top size criteria.
Process must be kept in tume. Safety screens
must be used and checked for wear.
Potential Problems: Oversize particles can cause block-
age of line and excessive wear.
3. Selection of Optimum Concentration and Pipe Diameter:
Engineer: Makes economic balance between diameter and
concentration based on specific slurry rheology.
Operator: Must adhere to minimum and maximum concen-
tration limits.
Potential Problems: Possibility of laminar flow if
slurry too thin; probably excessive pressure drop
if slurry is too thick.
4. Calculation of Pressure Loss
Engineer: Utilizes laboratory data on range of slurry
*Reprinted with permission from Thompson, TL. and T C Au^:
Slurry Pipeline Design and Operation Pitfalls to Avoid. Joint
Petrole^Mechanical^ngineering and Pressure Vessels and Piping
Conf. Mexico City, Mex., Sept. 19-24, 1976. Reference 93.
105
-------
characteristics plus commercial data; uses tested
hydraulic model capacity.
Operator:
Potential Problems: Wrong pressure (friction) loss can
either add to cost of system unnecessarily or reduce
system capacity.
5. Determination 'of Minimum Operating Velocity
Engineer: Specifies minimum velocity which provides
margin of safety above deposition or transition
velocity.
Operator: Must strictly enforce minimum operating
velocity.
Potential Problems: Operating below minimum velocity for
extended periods can cause blockage of line.
6. Determination of Operating Factor
Engineer: Include allowance for downtime, variation in
slurry characteristics and reliability of power
supply.
Operator:
Potential Problems: Improper operating factor in design
can result in inadequate throughput capacity.
7. Determination of Surge Pressures
Engineer: Must conduct detailed surge study.
Operator: Must adhere to valve closure times, relief
settings, etc.
Potential Problems: Possibility of overpressuring and
rupturing line.
8. Consider Bypass Capabilities
Engineer: Performs hydraulic and economic analysis of
bypassing alternate pump stations for reduced
throughtput capacities.
Operator: Adopts procedure for station bypass in emer-
gency situations.
Potential Problems: Bypass velocity criteria must be
.adhered to or line could be over-pressured.
B. CORROSION-EROSION
1. Establish Design Life
Engineer: Sets design life considering both contractual
life and probable operating life.
Operator:
Potential Problems: Later conditions may indicate de-
sirability of extending life and pipe wall thick-
ness could be inadequate.
106
-------
2. Establish Corrosivity of Water and Slurry
Engineer: Performs extensive laboratory tests on full
range-of slurry variations expected.
Operator: Monitors corrosion rate regularly; runs
laboratory corrosivity tests; monitors pH and
oxygen levels.
Potential Problems: Corrosivity of water or slurry
can cause irreversible damage to pipeline.
3. Select Slurry and Water Inhibitors
Engineer: Evaluates various inhibition methods consid-
ering cost, environment and effectiveness.
Operator: Strictly enforces inhibitor dosage criteria
and monitors effectiveness.
Potential Problems: Inhibitors must not interfere with
slurry dewatering and end use of solids.
4 . Minimize Oxygen Presence
Engineer: Designs system for minimum exposure of slurry
to oxygen.
Operator: Regularly inspects system for possible in-
gestion of oxygen.
Potential Problems: Oxygen can radically increase
corrosion rate.
5. Determine Metal Allowance
Engineer: Makes economic balance between inhibitor and
wall thickness additions.
Operator: Sets up & enforces regular corrosion spool
weight measuring program-uses ultrasonics as an
interim check.
Potential Problems:
6. Reduce or Avoid Slack Flow
Engineer: Conducts a computer analysis to determine all
slack flow areas especially during batching. Avoid
slack flow by reducing diameter, changing route or
installing choke stations. If some slack flow
accepted, must provide for replacement or lining.
Operator: Maintains chokes religiously, if installed.
Monitors wall thickness regularly in potential
slack flow areas.
Potential Problems: Undetected slack flow and resulting
cavitation can destroy the pipe wall in a matter of
months.
107
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C. OPERABILITY-STABILITY
1. Establish Desired Shutdown/Start-up Capabilities
Engineer: Analyzes slurry in laboratory and makes mod-
ifications as necessary to provide "soft" settling
slurry. Designs for start-up pressures.
Operator: Follows shut-down, start-up procedures.
Potential Problems: Deviation from start-up and shut-
down procedures could cause blockage.
2. Select Maximum Pipeline Slope
Engineer: Based on laboratory tests and operating ex-
perience sets maximum slope criteria. Makes trade-
off between cost of cuts for slope limitation and
potential risk with higher slopes.
Operator:
Potential Problems: Excessive slopes could cause
settlement to low point during shut-down with
possible formation of a blockage.
D. ATTRITION OF SOLIDS
1. In Pipeline
Engineer: Selects particle size, concentration, and
operating velocity to avoid excessive hetero-
geneity.
Operator: Adheres to concentration, size distribution
and velocity restrictions.
Potential Problems: Finer material is more difficult
to dewater & may have higher pressure drop (No
attrition observed, however, in properly designed
systems.)
2. In Pumps
Engineer: Sets particle top size compatible with pump
valve clearances.
Operator: Minimizes recirculation of slurry through
centrifugal pumps.
Potential Problems:
II. DESIGN/CONSTRUCTION
A. PUMP STATIONS
1. Number and Location of Stations
Engineer: Makes economic trade-off; diameter and number
108
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of stations; considers infrastructure.
Operator: Maintains accessibility to remote stations;
monitors power reliability.
Potential Problems: Additional remote stations give
operating complexity; plunger flush water can
cause excessive dilution with multiple stations.
2. Pump Type Selection
Engineer: Based on volume, pressure and abrasivity of
material selects piston, plunger or centrifugal
pumps.
Operator: Monitors pump parts life & establishes a
routine changeout schedule.
Potential Problems: Unexpected pump failures can shut-
down the system incurring lost production.
3. Number of Pumps per Station
Engineer: Minimizes number of pumps but includes ade-
quate spare capacity.
Operator: Schedules routine maintenance on spare pump
unit.
Potential Problems: Adequate sparing is important to
maintain high system reliability.
4. Driver Selection:
Engineer: Selects electric motor, diesel engine or
other considering cost, availability of fuel and
reliability.
Operator: —
Potential Problems: Poor selection of driver type can
have deleterious effect on system reliability.
5. Speed Control Selection:
Engineer: Selects speed control based on expected
throughput variations as well as start-up pro-
cedure. Sizes heat exchanger for maximum slip.
Operator: Follows speed versus time plan for start-up;
operates near minimum power consumption level.
Potential Problems: Improper speed control can raise
operating costs and make throughput adjustments
difficult.
109
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6. Pulsation Dampening
Engineer: Properly sizes and locates pressure damp-
eners.
Operator: Monitors vibrations and pulsations with
pressure transducers.
Potential Problems: Improper dampening can cause re-
duction in system capability or inoperability.
7. Pump Station Piping and Elbows
Engineer: Uses long radius elbows; avoids dead legs,
respects velocity limits in piping.
Operator: Monitors elbows and other potential high
wear areas.
Potential Problems: Dead legs can cause sanding;
short radius elbows will wear through.
8. Valves
Engineer: Uses Hard-facing in high pressure service;
avoids pockets where slurry can pack; considers
velocity.
Operator: Lubricates regularly as required.
Potential Problems: Valve wear or packing of solids in
cavities can result from poor valve selection.
B. AUTOMATION CONTROL
1. Degree of Automation
Engineer: Designs sophistication compatible with avail-
able technicians and needs of system.
Operator: is trained in use of all facets of automated
operation.
Potential Problems: Too complex a system can add oper-
ating and staffing problems.
2. Synchronization of Operation of Positive Displacement
Pumps
Engineer: Selects method of synchronization such as
speed control based on suction pressure.
Operator: Monitors set-points.
Potential Problems: Erratic operation & pressure
waves, could result from improper synchronization.
110
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C. PIPELINE
Degree of Tapering
Engineer :_ Tapers pipeline considering surge pressures,
static shut-off, head, corrosion allowance and in-
stallation.
Operator: ---
Potential Problems: Excessive tapering can cause over-
pressure problems as well as confusion in con-
struction.
Above Ground vs Buried
Engineer: Makes economic and environmental trade-off of
above ground vs. buried; considers thermal expan-
sion, susceptibility to freezing, pipe supports.
Operator: Maintains cathodic protection, coatings and
other protection.
Potential Problems : ---
Freezing Protection
Engineer: Considers burial below frost line, insulation
heat tracing and special operating techniques.
Operator: Maintains continuous monitoring of slurry
temperature; utilizes special operating techniques;
avoids shut-downs.
Potential Problems: Partially frozen line could rupture
or cause blockage.
Welding Standards
Engineer: Establishes welding standard for slurry
pipeline.
Operator: ---
Potential Problems: Excess weld metal penetration can
cause errosion through secondary turbulence.
External Corrosion
Engineer: Provides appropriate coating system, tests
leads and temporary protection.
Operator: Obtains corrosion survey after line has
"settled-in"; Installs required cathodic pro-
tection.
Potential Problems: Corrosion damage can occur very
rapidly in "hot spots".
Ill
-------
D. TANKAGE
1. Sizing
Engineer: Selects size and number of tanks for cost,
flexibility and reliability.
Operator:
Potential Problems:
2. Agitators
Engineer: Sizes to avoid solids deposits; reversing
types preferred.
Operator: Checks agitator for continuous operation;
watches for sanding, excessive vibration.
3. Special Tank Design
Engineer: Requires extra steel for maximum specific
gravity of slurry, access for cleaning required;
plans for desanding needed.
Operator: Maintains concentration below maximum;
practices desanding tank.
Potential Problems:
III. OPERATION
A. SELECT MODE OF OPERATION
Engineer: Prepares detailed operating procedure; sim-
ulate by computer if necessary.
Operator: Trains operators and follows prescribed oper-
ating procedure.
Potential Problems: Virtually all blockage and erosion
and corrosion "problems" are caused by operator
error either by improper monitoring for early
warning, or faulty procedures.
B. EMERGENCY TECHNIQUES
Engineer: Provides emergency procedures including plug
location and unplugging procedure.
Operator: Drills operators in emergency techniques and
procedures.
Potential Problems: Virtually all blockage and erosion
and corrosion "problems" are caused by operator
error either by improper monitoring for early
warning, or faulty procedures.
112
-------
C. STAFFING
Engineer: Prescribes staffing based on local availa-
bility and system design.
Operator: Staffs and trains; operators should be on
site during initial start-up.
Potential Problems: Virtually all blockage and erosion
and corrosion "problems" are caused by operator
error either by improper monitoring for early
warning, or faulty procedures.
113
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/2-79-067
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
The Environmental and Pollution Aspects of Coal Slurry
Pipelines
5. REPORT DATE
March 1979
issuing date
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
R. R. Faddick
8. PERFORMING ORGANIZATION REPORT NO
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Colorado School of Mines
Golden, Colorado 80401
10. PROGRAM ELEMENT NO.
1BB610
11. CONTRACT/GRANT NO.
R8 04614-01-0
12. SPONSORING AGENCY NAME AND ADDRESS
Industrial Environmental Research Laboratory
Office of Research and Development
U. S. Environmental Protection Agency
Cincinnati, Ohio 45268
13. TYPE OF REPORT AND PERIOD COVERED
Final (7/76 - 5/78)
14. SPONSORING AGENCY CODE
EPA/600/12
15. SUPPLEMENTARY NOTES
IERL-Ci Project Officer for this report was John F. Martin (513)684-4417
16. ABSTRACT
With the anticipated increases in coal consumption in the next decade, greater
demands will be made on existing transportation systems to move to market the abun-
dant reserves of coal in the U.S. Conventional transportation modes such as rail
and barge will have to expand their capabilities by overcoming whatever shortages
may exist in manpower, capital, and hardware. Simultaneously, lesser known systems
such as coal in water (slurry) pipelines will have to share the transportation load.
With some half dozen coal slurry pipelines being considered for construction within
the next five years pending eminent domain legislation, it will be a matter of time
before these lines are built.
A coal slurry pipeline system may impact the environment at three stages: design
construction, operation and maintenance; and in three areas: slurry preparation,
slurry piping and slurry separation. This work has examined these environmental and
pollution aspects of coal slurry pipelines. Such an effort will enhance the select-
ion_of better design, construction, and operation techniques to provide a balance of
engineering, economics, and environmental considerations.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
COSATI Field/Group
Barges
Coal Mining
Conveyors
Railroads
Trucks
Transportation
Water Quality
Air Quality
Coal Slurry Pipelines
Coal Transportation
Assessment
43E
43G
85B
3. DISTRIBUTION STATEMENT
Release to Public
19. SECURITY CLASS (ThisReport)'
Unclassified
21. NO. OF PAGES
120
20. SECURITY CLASS (Thispage)
Unclassified
22. PRiCE
EPA Form 2220-1 (9-73)
114
U. S. GOVERNMENT PRINTING OFFICE: 1979 — 657-060/1632
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