-------
higher energy consumption, the wet process is used because of the
raw material preparation, grinding and so on, in this form.
Table 3. ENERGY CONSUMPTION OF VARIOUS
CEMENT-MANUFACTURING PROCESSES
Energy
Consumption, Production Over
106 Btu/ton of Average Current
Process
Cement
Wet
Long Kiln
Calcinator and Short Kiln
Semiwet
Preheater and Short Kiln
Dry
Long Kiln
Suspension Preheater and
Short Kiln
Semidry
Grate Preheater and Short
Kiln
5.94
4.68
3.60
4.68
3.15
3.42'
Practice, %*
26.9
43.8
50.8
46.6
t
Includes 0.54 X 106 Btu/ton for drying.
Average current consumption is that of long kiln.
The other major type of kiln is the vertical kiln. The concept
of a vertical kiln is not new. Satisfactory performance of the verti-
cal kiln requires that the raw material be dampened and nodulized
prior to charging. In contrast to the rotary kiln, low-volatile fuels,
such as coal, are required. In the vertical kiln, the nodules and
fuel are fed continuously into the top of the kiln, and the clinker is
extracted, cold, from the bottom by a rotating grate. Fuel con-
sumption in a vertical kiln is about 3. 6 million Btu/ton of clinker
produced.
IV- 365
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Other methods of reducing energy consumption in the cement
industry include the installation of chain systems, kiln feed end enlarge-
ment, use of trefoils and kiln ledges, oxygen enrichment, increased
process control, slurry dewatering, and waste-heat utilization.
Air Pollution Emissions
The major air pollutant emissions problem in the manufacture
of portland cement is particulates, which occur in all phases of
cement manufacturing from crushing and raw material storage, to
clinker production, clinker grinding, storage, and packaging.
Emissions also include the products of combustion of the fuel used
in the rotary kilns; these are typically NO and small amounts of
j£
SO . However, many cement plants are switching fuel, from oil
X
and gas to coal and petroleum coke. These alternative fuels may
produce increased amounts of both NO and SO . However, no data
Jt ji
are currently available. Table 4 presents a summary of emissions
from cement-manufacturing processes currently in use.1
Most efforts to control air pollutant emissions focus on parti-
culates because they are not only the greatest problem, but also
the easiest to control. The most desirable method of control is to
collect the dust and recycle it by injecting it into the burning zone
of tiie kiln, thus converting it to clinker.
Combustion-related emissions are more difficult to control.
Nitrogen oxide emissions may be controlled by such techniques as
flue-gas recirculation, controlled mixing of the fuel and air, and
changes in burner block designs. The controlling factor to imple-
menting these techniques is economics. The emissions of SO , and
U.S. Environmental Protection Agency, "Compilation of Air Pollu-
tant Emission Factors," Publication No. AP-42, 2nd Ed. Research
Triangle Park, N. C. , April 1973.
IV-366
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Table 4. EMISSION FACTORS FOR CEMENT
MANUFACTURING WITHOUT CONTROLS3.b
Dry Process
Wet Process
Pollutant
Particulate
Ib/ton
kg/MT
Sulfur dioxide
Mineral source
Ib/ton
kg/MT
Gas combustion
Ib/ton
kg/MT
Oil combustion
Ib/ton
kg/MT
Coal combustion
Ib/ton
kg/MT
Nitrogen oxides
Ib/ton
kg/MT
Kilns grinders, etc.
245.0 96.0
122.0 48.0
10.2
5.1
Ne/
Neg
4 . 2 5g
2. IS
6.bS
3.4S
2.6
1.3
Kilns grinders, etc.
228.0 32.0
114.0 16.0
10.2
5.1
Neg
Neg
4.2S
2. IS
2.6
1.3
One barrel of cement weighs 376 pounds (171 kg).
These emission factors include emissions from fuel combustion,
which should not be calculated separately.
Typical collection efficiencies for kilns, dryers, grinders, etc. ,
are: rnulticyclones, 80 percent; electrostatic precipitators, 95
percent; electrostatic precipitators with rnulticyclones, 97. 5 per-
cent; and fabric filter units, 99.8 percent.
The sulfur dioxide factors presented take into account the reactions
with the alkaline dusts when no baghouses are used. With baghouses,
approximately 50 percent more SOj is removed because of reactions
with the alkaline particulate filter cake. Also note that the total SOj
from the kiln is determined by summing emission contributions from
the mineral source and the appropriate fuel.
These emissions are the result of sulfur being present in the raw
materials and are thus dependent upon source of the raw materials
used. The 10. 2 Ib/ton (5. 1 kg/MT) factors account for part of the
available sulfur remaining behind in the product because of its
alkaline nature and affinity for SO^.
Negligible.
ft
S is the prccent sulfur in fuel.
-------
the other major combustion-related emissions, are inherently con-
trolled in the burning process because most of the raw-material feed
is converted to calcium oxide, which reacts with the sulfur dioxide.
In addition, the presence of sodium and potassium compounds in the
raw material aids in the direct absorption of sulfur dioxide into the
product. Sulfur dioxide is also removed by this same mechanism
in baghouse filters, in which the sulfur-dioxide-laden gases contact
the collected cement dust. However, the degree of control by sul-
fur dioxide absorption depends upon the alkali and sulfur content of
the raw material and fuel.
Cement Industry — Field Survey
A series of interviews were made with cement manufacturers
to obtain information related to current operating practice, including
fuel availability, potential for process modification, and pollution
control problems. The companies interviewed employ both the wet
and dry cement manufacturing processes and range from limited to
widespread operations on a geographical basis, and from single to
multi-plant operations.
The amount of energy required to produce one ton of cement
ranged from a high of 7 X 106 Btu to a low of 4. 3 X 106 Btu in a
plant equipped with preheaters. Fuels consumed in kiln operation
consist of natural gas, oil and coal. Users of natural gas reported
curtailments ranging from 10% of base year (1972) use to complete
curtailment during the winter season. The range of gas curtailment
is subject to geographical location, and where intrastate supplies
are available, the curtailment is less than from interstate sources.
The price of natural gas has increased markedly from 1972 levels
of $0.32/1000 CF to $0. 50/1000 CF in early 1975. Further cur-
tailments and increased prices are expected by the firms contacted.
Coal has been available in adequate amounts although the price
has increased dramatically,in one case doubling over the period of
IV-368
-------
one year. One firm reported a price increase of $0. 35/106 Btu,
from $0.42/106 Btu in 1972 to $0. 77/106 Btu in 1974. In another
instance, a firm stated the contract price of coal had gone from
$17. 50/ton in 1974 to $27. 50/ton in 1975. In contrast to this, the
spot price of coal declined from $40/ton in 1974 to $31.00/ton in
early 1975. As a result, this firm is seeking coal purchases amount-
ing to 50% of its needs on the basis of a 5 year contract. In the past,
spot prices had been lower than contract prices and it was possible
to purchase coal cheaper on the open market. It is expected that this
price relationship will not occur again and greater reliance will be
placed upon contractual purchases. The sulfur content of the coal
used is 2-1/2% or less. Some of the plants not currently using coal
cannot do so because of physical limitations. Much space is re-
quired for coal-handling equipment and storage. Some older plant
sites do not have access to additional space. Other plants do not
have ready access to coal due to transportation problems, such as
distance and cost.
One of the firms contacted had some kilns equipped with air
preheaters and some without. A reduction in energy consumption
of about 20% was reported for the kilns equipped with the preheaters.
The amount of energy consumed in kilns with preheaters was about
4. 3 X 106/ton, in kilns not equipped with preheaters the energy re-
quirement is about 5. 3 X 106 Btu/ton. Another company had in-
stalled preheaters on a trial basis and found them to be unsuccess-
ful. It was found that the raw material clay contained an excessive
amount of oil which caused fires. As a result, the company re-
covers waste heat for use in the steam generation of electricity.
Suspension preheaters require additional horsepower for con-
trolling air movement within the plant. The following power re-
quirements were given as examples:
IV-369
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Process
kWhr/bbl
Wet processing plant w/o preheater
Dry processing plant w/o preheater
Wet or Dry w/preheater
5. 3bbl/ton of cement.
25-28
29-34
38-43
In addition to the increased power requirements of air suspen-
sion preheaters, it was stated that the raw materials must be
properly sized to achieve optimum utilization. The material must
be in the range of 1/2-inch to 2 inches in diameter to assure circu-
lation of the preheated air. Material smaller in diameter tends to
cake and restrict air flow. If the raw materials used have a high
level of alkali salts, the cement produced will have a high alkali
content. The raw materials can pick up the sulfur emitted in the
waste-heat stream and add to the problems of sulfur control brought
about by the sulfur content of the fuel used in firing the kiln.
As in the case of coal, some older plants can be restricted in
the application of preheaters by the amount of space available within
the plant for the installation. Such an installation could be readily
incorporated into the design of a new plant.
None of the firms interviewed had experience with the operation
of a vertical kiln. One firm had no knowledge of any experimental
testing. The other firms followed the work going on in Europe and
Japan with vertical kiln operation. From the impression given in
the course of the interviews, it does not appear that vertical kilns
will be accepted favorably by U. S. industry. Each of the firms
stressed the capacity limitations of the vertical kilns, many such
kilns would be required to equal present installed capacity. A
second disadvantage of the vertical kiln is poor product quality.
The kiln is stationery and the raw material falls by gravity through
the kiln. The raw material has a tendency to cake and block passage
because of the lack of agitation.
IV- 370
-------
Two of the firms contacted expressed an awareness of oxygen
enrichment as a means of reducing fuel consumption. Tests results
were unsatisfactory; in one instance the amount of fuel required was
only reduced by 5%. Oxygen enrichment is not economical in terms
of oxygen cost and does not conserve fuel when the amount of energy
required to produce the oxygen is taken into consideration.
Of the firms contacted only one had chain systems installed in
their kilns. One firm utilized waste heat for electricity generation
and the other used waste heat in the operation of preheaters. The
firm using chains reported satisfactory results and stated that the
temperature of waste gases was reduced to the lowest practical
limit.
All of the firms were able to comply with local, state, and
Federal emission requirements by the use of baghouses. These
systems trap particulate matter which evolve primarily from the
kiln and the clinker cooler. Electrostatic precipitators have been
installed on a limited basis, but were found less satisfactory than
baghouses. Corrosion of the unit and water disposal were two of
the main problems encountered.
Disposal of the particulate matter is a major problem in the
industry. One firm is faced with the problem of disposing of 650
tons of waste per day and this is expected to double in the next ten
years. The material must be hauled by truck to suitable landfill
sites. In some states the landfill site must be specially prepared
to prevent seepage of salts into sub-strata water. In many instances
the expense of equipping an older kiln with the proper dust-handling
equipment cannot be economically justified and have been phased out
of service.
The solid particulate matter cannot be recycled into the raw
material stream because of its alkaline content. The alkali content
of low-alkali cement cannot exceed 0. 6% per ASTM standard. If
IV- 371
-------
this standard were revised upward to 1. 5%, it was stated that all
of the collected particulate matter could be recycled and the land
disposal problem would be solved. The alkali salts react with the
aggregate used in the final concrete product, and fee cement manu-
facturer has no control over the type of aggregate used. The opin-
ion was given that increased alkalinity would not affect the quality of
the cement.
Emissions of SO and NO are not as large a problem to the
Jt •&
industry. SO emissions are controlled primarily by use of low-
sulfur fuels and controlled burning practice. The sulfur in the
waste-heat stream reacts with the particulates collected and the
raw materials as they are fed into the kiln. NO is not a major
JW
problem because of the absence of legislation.
Suggested areas of further research included —
• Investigation into the substirutability of Type 2 cement for
Type 1 cement.
• Investigation of alkali reaction problems that are of a local
geographical nature.
• Improved process control to monitor combustion practice to
conserve fuel.
• The development of combustion technology to reduce NO .
IV-372
-------
Glass Industry
The manufacture of glass involves three major energy-consuming
processes: melting the raw materials, refining the molten glass,
and finishing the formed products (as shown in Fig. 2). Typically,
about 80% of the energy consumed by the glass industry is for melting
and refining, and 15% is for annealing. The remaining 5% is for
"others" such as mechanical drives and conveyors (shown in Table 5).
Table 5. BREAKDOWN OF ENERGY CONSUMPTION
BY THE GLASS INDUSTRY IN 1971*
Flat Glass
(SIC Code iZH)
Glass Produced, 106 tons
Energy Consumption, 1012 Btu
Melting
Annealing
Other
Total Energy Consumption,
1012 Btu
Average Energy Consumption
for Melting, 1 Ok Btu/ton of
glass
Average Energy Consumption for
Entire Production, 1 O6 Btu/tnn
44. 7
8. 4
2. 8
55.9
17. 5
21.8
10. 90
104. 3
19. 6
6. 5
130.4
9. f,
12. 0
Pressed and
Blown Glass
(SIC Code 32Z9) Total
3. 50
SO, 5
9. 5
3. 2
63. 1
14, 4
1R. 0
16. 96
199. 5
37. 5
12.5
249.4
11. R
14. 7
Excludes energy consumed for electricity generation.
A-84-1402
Glass Melting and Refining
Both continuous melters and batch melters are used in the glass
industry, depending upon the output. Continuous melters are used
in the production of large-demand container glass (bottles, jars),
flat glass, and plate glass. Batch melters are used for specialty
glasses, high quality optical glass, and hand-blown glass products.
Continuous melters are normally maintained at temperature through-
out a compaign, which might extend from 4 to 6 years. Batch
melters are shut down frequently and allowed to cool off. Table 6
is a summary of the melting and refining equipment used in the
glass industry.
IV-373
-------
SILICA SAND
Si02
SODA ASH
NdoCCK
LIMESTONE
MgO • CaO
R20-AI203'6Si02
BATCH MIXING
MELTING
2700°F
REGENERATIVE FURNACE
SUBMERGED THROAT-
REFINING
2300°F
1472- 20I2°F
FINISHING
FABRICATION
ANNEALING
INSPECTION
PACKING |
AREHOUSING
A-83-1249
Figure 2. FLOW DIAGRAM FOR SODA-LIME
GLASS MANUFACTURE
IV- 374
-------
Table 6. GLASS-MELTING AND REFINING EQUIPMENT
Continuous Melters
Melting Tank
Refining Section With Premix Burners
Batch Melters
Unit Melters or Day Tanks
Batch Melters for Optical and Special Glass
Crucible or Pot Melters
Continuous Melters
Continuous melters in the glass industry are reverberatory
furnaces equipped with checker-brick regenerators for preheating
combustion air. Depending upon the firing arrangement used, the
melters are classified as end-port or side-port fired (shown sche-
matically in Figures 3 and 4). However, further breakdowns are
made, based on the location of the burners relative to the air inlet
ports. The burners can be placed over the air ports, through or at
the air port sidewalls, or underneath the air ports. Each firing
configuration produces a different flame geometry with different
heat-release characteristics, yet the overall thermal efficiency of
furnaces with any of these configurations is typically about
The fuels consumed in the melting process are primarily natural
gas and fuel oil. However, the use of submerged electrode electric
melting is increasing due to the air pollutant emissions and low
thermal efficiency of fuel-fired melters. Typically, a fuel-fired
melter consumes about 6. 0 million Btu/ton of glass melted, com-
pared to about 3. 0 million Btu/ton of glass melted in electric melters
(excluding energy consumed for electricity generation). However,
this figure is known to vary considerably, depending upon such fac-
tors as furnace insulation, combustion control equipment, molten
glass depth, and type of glass being produced.
IV- 375
-------
Figure 3. PLAN VIEW OF SIDE PORT FLAT GLASS FURNACE
IV- 376
-------
OJ
O
CM
Q
2
W
u
s
>H
H
h
O
H
U
W
W
A
Q
P
H
i— (
O
S
O
*tf
(U
3
IV-377
-------
Note that these fuel consumption figures apply to furnaces
during melting operations. However, data on energy utilization
(Table 5) indicate that energy consumption is actually higher be-
cause operation is suspended many times during the year for
breakdowns and holidays. During these periods, the furnaces are
idled to maintain furnace temperature while production stops. Thus,
energy is consumed but no glass is produced, thereby increasing
the overall average energy consumption per ton of glass produced.
An even greater source of discrepancy is the variation in the amount
of cullet, i. e., recycled glass, used from one glass plant to the next.
The amount of cullet charged varies from 10% to 30% of the total
raw material charged to the melter. Lower percentages of cullet
charged result in higher fuel consumption. In general, economic
considerations prevent higher percentages of cullet from being
charged.
Continuous Refineries
After completion of the melting phase, the molten glass flows
into the refining section where the glass temperature is reduced
and the glass is degassed. Refiners vary from plant to plant. In
some cases, it is an integral part of the furnace, separated from
the molten area by a wall, but taking its heat from the combustion
in the melter. In other cases, the refiner is separate from the
furnace and is heated with burners of its own, separate from the
melter. Premix burners are used in this application, and due to
strict quality control of characteristics such as color, natural gas
is the preferred fuel. The total energy consumed for melting and
refining glass represents about 80% of the total energy consumed
by a typical glass manufacturing plant.
Batch Melters
A very large amount of glass, particularly for pressed or
blown products, is produced in batch melters. These are classed
IV-378
-------
as day tanks or unit melters, and crucible or pot melters. Crucible
or pot melters are small rectangular or circular structures. Open
pots — round crucibles with capacities of 1 to 2 tons of glass —
are used in rectangular furnaces in which thick plate glass is cast
or special glass compositions are made. In circular pot furnaces,
covered pots are used for melting relatively small amounts of
special compositions, thus protecting the glass from the flames.
One advantage of pot furnaces is that different glass compositions
can be handled simultaneously, and the temperature of each pot is
controlled individually, within a limited range. Pot furnaces are
typically, although not always, provided with regenerators for fuel
economy.
Day tanks, or unit melters, are built up with refractory blocks,
thus differing from the pot, which is a single piece of refractory.
Day tanks are usually fired separately, rather than in groups, and
they have greater capacities than pots. In addition, they can be
heated to higher temperatures than pots, thus permitting the melt-
ing of compositions not particularly adaptable to pot-melting. Re-
fining of the glass in both pot melters and day tanks is carried out
as part of the melting operation in the same physical unit. The fuels
used in batch melters are natural gas and oil, although some melters
which produce optical-quality glass or colored glass may be restricted
to using natural gas because of the potential adverse effect of liquid fuels
on the quality of these glasses.
Glass Annealing
Annealing is the other major energy-consuming operation in the
glass industry, accounting for approximately 15% of the total energy
consumed. While annealing of large handmade ware may be carried
out in batch ovens, most ware from either batch or continuous-
melting operations is annealed in large tunnel-type ovens provided
with moving mesh-belt conveyors. These ovens, known as lehrs,
are temperature zoned, starting at about 1200°F, at the glass input
and decreasing in such a way that the cooling curve of the ware
IV-379
-------
precisely matches that required to obtain a strain-free product. The
size and arrangement of the lehrs depends on the characteristics of
the ware being annealed. Large ware with thick walls requires slow-
er annealing rates than small ware with thin walls.
Lehrs are heated by convection, radiation, or a combination of
the two. The most effective means, which provides the greatest
control and temperature uniformity critical to the production of
strain-free glass, is by zoned, convection lehrs with internal distri-
butors to obtain lateral temperature uniformity. External fans and
heater boxes are used in these lehrs, which makes it possible to use
either natural gas or oil as fuel. However, some lehrs are direct-
fired by atmospheric or premix burners or by excess air burners.
In this case, natural gas is the only fuel used so that the glass is not
likely to be contaminated by the "clean" combustion products.
Annealing lehrs generally operate at a thermal efficiency of only
20%. Much of the inefficiency is due to poor maintenance and oper-
ating practices. Most lehrs leak a considerable amount of unwanted
cold air into their chambers or lose heated air through unwanted
openings.
Air Pollution Emissions
In addition to being the primary consumer of energy in the glass
industry, the glass-melting furnace is also the primary source of
air pollutant emissions. The primary emissions are particulates,
sulfur oxides (SO — sulfuT dioxide and sulfur trioxide), nitrogen
3C
oxides (NO — nitric oxide and nitrogen dioxide), and carbon mono-
xide. Hydrocarbons are not a problem if proper combustion con-
ditions are maintained. Table 6 summarizes emissions from various
glass-melting tanks as measured by a number of investigators.
Air pollution emissions from annealing lehrs are not considered
to be a big problem. These emissions (CO and unburned hydro-
carbons) occur almost entirely as the result of incomplete combustion
IV-380
-------
Table 6. AIR POLLUTANT EMISSIONS FROM
VARIOUS PRODUCTION GLASS MELTERS
CO
NO
Investigators ppm-
IGT2 35-50a
Ryder and McMackin4 0-5b
Stockham5 375C
Arrandale1
Netzley3
a 8% excess air.
25-45% excess air.
c Excess air unknown.
Variable with production rate.
Natural gas fired.
490-700
450-600
340
Particulates,
Ib/hr
6-8
2-lOd
2-lOd
Halogens SO
-ppm-
1.0
7.1
28e
267
resulting from improper use of the combustion equipment. The one
exception is SO , which is emitted because of the sulfur in the fuel.
However, since oil is the only fuel containing sulfur used in lehrs and
its use is very limited, the amount of SOX emission is insignificant.
Factors Affecting Air Pollutant Emissions^
Several factors influence the emission rate of particulates
from a glass-melting furnace, including batch composition, batch
preparation, and type of fuel. The production rate of the furnace
also is a factor.
Measurements of stack emissions from a glass melter have
shown that the particulates emitted are primarily sodium sulfate,
IV-381
-------
which is a minor ingredient of most glass batch. In the furnace, it
vaporizes and decomposes to form elemental sodium and sulfate.
When these gases pass through the checker-brick and are cooled,
sodium sulfate is re-formed. Only about 40% of the sodium sulfate
charged into the furnace is vaporized; the remainder goes into the
glass. In addition to the sodium sulfate, a small amount of raw batch
that is carried out of the furnace by the flue gases is emitted. This
emission can be minimized by proper batch preparation, consisting
primarily of wetting the material before charging it into the furnace.
The amount of SO emitted from a furnace depends on 1) the
j£
sulfur content of the fuel and 2) the amount of sulfur-bearing com-
pounds in the raw materials. Consequently, natural-gas-fired fur-
naces generally exhibit lower SO emissions than oil-fired furnaces
Ji
unless the sulfur has been removed from the oil. Measurements of
SO emissions from a batch melter charged with batches of various
x
sulfur content showed a direct correlation between sulfur in the batch
and SO emitted. The greater the sulfur content of the raw batch,
3£
the higher the SO emissions.
3C
The amount of NO emitted from a glass-melting furnace de-
3£
pends upon several factors, some of which are not understood. One
important factor is flame temperature: NO formations in the fur-
3t
nace increase as flame temperature increases. For example, during
a recently completed experimental program, NO emissions were
ji.
measured during a complete firing cycle of a glass melter. NO
emissions were highest at the beginning of the firing cycle and then,
as the cycle continued, decreased by about 30%. At the beginning
of the firing cycle the combustion air is preheated to a higher tem-
perature, which results in a hotter flame than at the end of the
cycle, when the checker-brick and hence the air have cooled con-
siderably. Other major factors in NO formation in a glass melter,
such as flame velocity and recirculation patterns of flue gases, are
being studied.
IV-382
-------
Methods of air pollution control currently in use in the glass in-
dustry are primarily electrostatic precipitators (ESP) and baghouses
for particulates, and the use of low sulfur oil for SO emissions. In
X.
terms of equipment costs, ESP and baghouses are about the same
upon installation. However, less energy is consumed by ESP. To be
effective, baghouses require a substantial pressure differential which
creates a need for a substantial amount of horsepower to move the
particulate-laden air through the house. In addition, baghouses re-
quire more maintenance than ESP to be totally effective.
One of the problem areas faced by the glass industry in its at-
tempts to clean up their emissions is the variances in regulations that
exist from one state to the next. More than one company interviewed
indicated that because of these variances, different solutions must be
implemented to bring two plants, located in different states but other-
wise identical, into compliance. Thus in one state, baghouse systems
may adequately control a company's partic-ulate emissions, while in
a neighboring state a process modification, the use of electric melters
instead of fossil-fuel-fired melters is necessary. Such variances are
not only costly to a company, but also may dramatically effect energy
utilization as in the above example.
Other emissions, such as carbon monoxide and hydrocarbons,
can be controlled easily with proper combustion conditions. If opal
or green glass is being produced, halogens such as chlorine and
fluorine also are emitted in very large quantities from a fossil-fuel
melter. However, the industry has converted completely to electric
melting, and this swatch has eliminated these emissions.
Glass Industry-Field Survey
According to the glass industry, there exist several process
modifications for potential implementation by the industry sometime
in the future which would affect energy utilization and/or air pollu-
tion emissions. These are —
IV-383
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• Expansion of process monitoring and control capacity
• Electric melting
• Electric boosting
• Oxygen enrichment
• Raw batch preheating
• Raw batch agglomeration
• Use of low-temperature heat to drive compressors
• Augmentation of heat transfer from flames
• Submerged combustion.
Of these modifications, only the first three are considered by the
industry to have potential for implementation in the near future.
This is due primarily to the fact that such techniques are economi-
cally feasible and technical feasibility has been demonstrated to the
satisfaction of the industry, so that implementation is already occur-
ring. According to industry, the latter modifications listed are
generally considered to be economically unattractive or technically
unfeasible in spite of the published data to the contrary. The fol-
lowing discussion presents a brief description of the modifications
involved and the industry's viewpoint concerning implementation
•with respect to each.
Expansion of Process Monitoring^jj.nd Control Capacity
There are several modifications which can be made in the area
of process monitoring and control which will favorably influence the
utilization of energy in a downward direction, according to persons
interviewed within the industry. One such modification is the use
of improved temperature-sensing devices for continuous-process
monitoring. For example, infrared sensors focused on critical
areas of the melter, such as the optical block on the bridgewall,
which are used to gauge melter performance, can be used not only
to continuously monitor melter temperature, but also the signal
from such a unit can be used to control fuel input based on melter
temperature. Another such modification is the use of flue-gas analyses
to monitor excess air and maintain it at a minimum level. None of
IV- 384
-------
these monitoring techniques are expensive and all of them would con-
tribute to improving the efficiency of operation,
Electric Melting (and Boosting)
Primarily for purposes of reducing air pollutant emissions, the
glass industry strongly supports the implementation of electric
melting and boosting. Electric melting, as a method of producing
glass, has been proven technically and, in most cases, economically
feasible by virtue of its relatively widespread usage within the in-
dustry. (Actually, electric boosting, wherein a fuel-fired melter is
supplemented by electric melting, is very popular and more preva-
lent within the industry than pure electric melting. )
Oxygen Enrichment
Oxygen enrichment is a technique whereby pure oxygen is added
to the combustion air of a fuel-fired melter, resulting in an increase
in flame temperature, which in turn results in a reduction in fuel
required to melt a ton of glass, or alternatively allows a melter
operating at design capacity to boost its production above design
capacity. Based on the results of the interviews with glass manu-
facturers, oxygen enrichment is a long term goal, primarily because
acceptance by the industry requires substantial changes in fuel and
oxygen costs to economically justify implementation.
Raw Batch Pretreatment
The area of raw batch pretreatment inclxides batch agglomeration,
or compaction, and preheating of the batch prior to charging into the
furnace. Most companies interviewed feel that batch agglomeration
is not economically justified within the near term for reasons of re-
duced energy utilization or reduced particulate emissions. However,
at least one major glass manufacturer has recently put into operation
several pelletizing lines to supply pelletized batch to the melters.
At the present time, there are no data available regarding the spe-
cifics of this operation.
IV-385
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Coupled with the compaction of glass batch is the idea of pre-
heating it prior to charging into the melter. It is clear that such
a process must be coupled with a batch-compaction process in order
to minimize batch losses during preheating and to minimize partic-
ulate emissions from the batching operation. The industry contends
that preheating of the batch will cause it to become sticky, making
the charging operation next to impossible.
Submerged Combustion
Submerged combustion is a melting process whereby the fossil-
fuel burner is located beneath the molten glass surface and the hot
combustion products pass through the glass resulting in a very high
rate of heat transfer from the gases to the glass. Because the pro-
duct from this type of melter is foam glass, that is, it contains
millions of air bubbles, it is unacceptable to the industry as such
for use without substantial refining. The only possible use for sub-
merged combustion would be in a premelter, which at least one com-
pany has implemented. Because the refining step requires a sub-
stantial amount of energy (more than usual), it is not clear that
there is a reduction in the overall amount of energy consumed to melt
the glass. Consequently, substantial development is still required
before it will become acceptable to the industry, making implementa-
tion long-term at best.
Augmentation of Heat Transfer From Flames
This is a rather nebulous area for consideration in that there
are potentially numerous things which can be done to improve heat
transfer from the flame to the molten glass. One such example is
the use of devices which allow an operator to accurately and precisely
position the burners. A second example is the injection of water
vapor into the flame which theoretically increases the radiative pro-
perties of the flame, resulting in an increase in heat-transfer rate.
The entire area of augmenting heat transfer has great potential,
IV- 386
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according to the industry, but implementation of most of the develop-
ments is deemed to be long term.
Use of Low Grade Thermal Energy
At least one company interviewed expressed the opinion that
waste heat from the melting process, most of which is below 1000°F
and consists of 20% of the energy that goes into melting the glass,
could be used to directly drive turbines for air compressors which
•would then be used in the blowing operations. Alternatively, but not
as efficient, was the suggestion that this heat be used to drive tur-
bines in the generation of electricity. While such practices are not
currently used, with some development, usage might increase in
the long term.
Improvements in Equipment Design
Because of the rate at which equipment is replaced within the
glass industry, implementation of improvements in equipment design
are considered long term. Improved energy utilization is expected
from the application of better insulating techniques, improved regen-
erator design, and improved firing patterns by burner placement.
Annealing lehr efficiency is effected by numerous design considera-
tions. Among the most prominent considerations are the use of light-
weight lehr belts, method of belt return, proper insulation of the
heating zone, use of radiant burners in the heating roof section, and
design to prevent forward drift. Plant layout to minimize transit time
of the glass between the forming machine and lehr is also important.
As indicated, most of'these design modifications are considered long
term in terms of implementation and impact.
1 V- 337
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Aluminum Industry
Primary aluminum, manufacture is divided into four basic
operations: mining the bauxite; refining the bauxite into alumina;
smelting the alumina into aluminum; and melting and reheating of
the aluminum for forming, casting, rolling, and shaping. Since this
program is concerned with the combustion processes in aluminum
manufacture, this categorization will only deal with the bauxite re-
fining process in primary aluminum manufacturing and all of the
heating processes in secondary aluminum manufacturing.
Bauxite Refining
The refining of bauxite to obtain alumina is accomplished in the
Bayer Process. The objective of this process is to separate out the
impurities, which include iron oxide, silica, and titanium dioxide.
The first step in the Bayer Process is digestion of the bauxite
into a solution of hot caustic soda. The product of the digestion pro-
cess is a liquid containing dissolved alumina. This liquid is cooled
and hydrate alumina is allowed to precipitate out of the solution.
The precipitate is filtered, washed, and then heated in rotary kilns
at 1800°F, resulting in commercially pure, dry alumina. The rotary
kiln equipment and technology are similar to that used in the cement
industry.
Smelting
The smelting process, wherein alumina is converted to aluminum,
is an electrolytic process, and thus does not concern this program-
However, the process depends on the production of carbon anodes for
use in the pots and this production requires large amounts of fuel,
not only as a source of carbon, but also for drying and baking the
anodes once they are formed. The drying is done in rotary kilns or
vertical-shaft kilns, similar to those used in the cement industry.
V- .588
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Baking is done in batch-type box furnaces or continuous ring-type
furnaces.
Batch-Type Furnaces
Batch-type furnaces are, typically, box furnaces, fired pri-
marily -with gas or oil and varying load capacity from 100 Ib to
over 200, 000 Ib. Because they are batch-type furnaces there is
a considerable amount of energy wasted during a typical cycle,
•which includes charging the material, heating up the furnace for
baking, and then cooling down the furnace for unpacking and reload-
ing with fresh charge. Fig. 5 shows a typical cycle, relating the
time and temperature for baking carbon. The cycle varies accord-
ing to such parameters as type and size of electrodes processed and
the size of the furnace being used. Typically, a box-type furnace
consumes about 18 million Btu/ton of carbon baked.
Ring-Type Baking Furnaces
Most of the furnaces used for anode baking are of this type. The
operation of a ring furnace is cyclical and can be broken down into
five steps: loading, preheating, heating, cooling, and unloading.
Most ring furnaces are gas-fired, using either natural gas
or producer gas. They are also regenerative furnaces, thus afford-
ing economies in fuel consumption. Additionally, the waste heat of
the combustion products is used in the preheating step. Such eco-
nomies result in a typical fuel consumption rate of 9 million Btu/ton
of carbon baked — about 50% less than the box-type furnaces,
Primary Aluminum Melting
Aluminum melting is accomplished in furnaces at temperatures
of about 2000°F. The types of furnaces used for melting are —
IV-389
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o
o
UJ
£C
o:
uj
a
2
UJ
i-
UJ
o
<
z
oc
1000
900
800
700
600
500
400
300
200
100
COOL
05 tO 15
TIME, days
20
25
A-124-2238
Figures. TYPICAL OPERA TION AND
THERMAL CYCLE FOR BAKING CARBON
IV- 390
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* Large and small stationary tilting reverberatories
• Holding furnaces (reverberatories)
• Tilting, barrel-type furnaces
• Stationary and tilting crucible furnaces
• Dry-hearth mclters.
The type of furnace used depends on a number of parameters in-
cluding —
• Quantity of metal required
• Type and form of charged materials
• Desired melting rate and temperature control
• Type of product.
Of the various possible types of furnaces, batch-type reverberatory
furnaces are the most commonly used. They are usually rectangu-
lar, refractory-lined boxes with burners at one sidewall and charg-
ing doors above the metal line along one side. These melters vary
in capacity from less than 5 tons to over 80 tons. Aluminum mel-
ters, considering only melting, are designed for melting rates as
high as 65 Ib/sq ft-hr. If charging, holding, and discharging are
also considered, the melting rate decreases to about 35 Ib/sq ft-hr.
Fuel efficiency for these melters is about 30%. Dry-hearth furnaces,
another type of reverberatory furnace, can melt at a rate of 100 lb/
sq ft-hr, but are not used for high-quality aluminum-alloy production.
Crucible or Pot^ Furnaces
Crucible or pot furnaces are used in cases where the required
capacity, generally 30 to 1000 lb? is low and the need for flexibility
is high. Crucible furnaces are used for melting as well as holding.
They may be stationary or tilting, or the crucible may be removed
and transferred to the casting area. Heat transfer in a crucible
furnace is through the crucible walls. Burners are situated tangen-
tially around the furnace to supply tiniform heating to the crucible.
The modes of heat transfer to the- pot are primarily convection and
IV-391
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radiation; however, in the case of convection, direct impingement
is avoided as hot spots will reduce crucible life and interfere with
the control of the metal temperatures. Use of these modes of heat
transfer results in an average fuel efficiency of about 15% to 20%,
as opposed to 30% in reverberatory furnaces where heat is trans-
ferred directly from the flame and surrounding refractories to the
metal surface.
Burner Equipment and Firing Arrangement
Both premix and nozzle-mix burner equipment are used for
aluminum melting. Premix burners, both the aspirator and inspir-
ator types, are used primarily on small crucible melters, parti-
cularly those that are fired tangentially. Only nozzle-mix burners
are used on the large-scale melters because of the longer, more
luminous flame and adaptability to dual fuel firing. Normal prac-
tice is to use a few large burners (10 to 20 million Btti/hr) rather
than several smaller burners. Some burner designs are quite
similar to those used on steel-mill soaking pits having the capability
of adjusting the flame geometry to suit melting-chamber require-
ments. Roof-firing with radiant burners, although theoretically ideal
for heating aluminum where flame impingement on the bath surface
is undesirable because of high oxidation loss, is not used on the
large, side-charged melters because of the severe splashing pro-
blems encountered. Radiant burners are, however, used on smal-
ler reverbs that are charged through endwall charging wells and on
holding furnaces where a relatively quiescent atmosphere is very
desirable.
One of the preferred firing arrangements for large reverbs is
the W-flame, two-pass geometry. In this arrangement, two burners
are located in one endwall, with the flue port located below the burn-
ers on the furnace centerline just above the metal line. The high-
velocity, hottest flue products are well above the bath and transfer
IV- 392
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heat directly to the arch, while the cooler, low-velocity combustion
products are distributed over the entire bath surface area and trans-
fer heat to the bath with a minimum of flame impingement.
For the holding furnace, which requires a much lower input,
single-pass firing is more desirable. The burners are at one end
of the furnace and the flue is at the other, avoiding the danger of
short-circuiting to the flue that is inherent with the W-flame design
at low burner input.
Natural gas, LP gases, distillate and residual fuel oils, and
electricity can all be used satisfactorily to heat the large reverbera-
tory melters, although natural gas has been preferred because of
low cost, cleanliness, and controllability. Induction melters have
reached the 15-ton melter-capacity level. However, the interest in
induction melting in the program is low and will not be considered
in detail.
Aluminum Reheating for Forging and Extrusion
Almost all of the fuel-fired furnaces used for heating aluminum
and aluminum alloys for forging and extrusion are of the convection
type and are indirectly heated. Indirect heating with radiant tubes
is preferred, particularly for alloys sensitive to surface reactions
with combustion products. The heating furnaces are typically con-
tinuous, using chain or slot conveyors and distributing the heated
air through ported or slotted tubes or through plenum chambers.
The wind-flow distribution systems can be transverse, longitudinal,
or vertical, depending on the mass, size, shape, and loading of
the stock being heated; allowable tempe rature drop in the circulating
wind; required heating rate; and allowable temperature variation
in the heated stock. Heating-wind temperatures is normally about
75°F hotter than the final stock tempe rat ure.
IV-393
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A flame-impingement furnace is frequently used for heating
"soft" aluminum alloys for extrusion but not for heating the "hard"
alloys because of adverse effects on surface metallurgy and the in-
ability to control billet temperature within required limits. In this
furnace, the billets are conveyed on alloy brackets fastened to a
heavy-duty conveyor chain that runs cold below the bottom of the
furnace. The alloy brackets extend through a slot in the bottom
of the furnace and support the billets on the centerline of the heating
chamber. A row of premix "blast" burner tips fire horizontally
at the billet centerline. Heating rates of about 2 to 3 minutes per
inch of billet thickness are normally maintained. The lower half
of the furnace is made up of two separate, sequented, cast-
refractory sections individually supported by the furnace structural
elements. The top part of the furnace is made up of a number of
half-circular cast refractory sections with flue ports at the top.
The flow of ambient air up through the conveyor slot, by draft
effect, cools the chamber walls to approximately the local billet
temperature. This minimizes the risk of billet overheating, or
even melting, during production delays. These gas-fired, rapid,
billet heaters represent major competition to 60-cycle induction
heaters for aluminum extrusion. Input to each furnace zone is con-
trolled by a radiation-type, temperature - me asurement instrument
sighting at the billets through an open tube between the furnace zones.
Unfortunately, if a billet is not loaded onto each conveyor fixture,
the instrument sights on an open space and calls for maximum in-
put, incurring the danger of overheating or melting the billets.
Typical operating problems with the impingement billet heaters are
a) poor billet temperature control after a production delay or a change
in production rate, b) overheating or melting of billets if a gap is
left on the conveyor, c) conveyor maintenance, and d) refractory
failure.
IV- 394
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Forging or extrusion temperatures for aluminum and for most
aluminum alloys are usually 750° to 850°F. Some of the "hard"
alloys are forged at 900° to 920°F. The heat content of aluminum
above ?00°F and corresponding fuel-input requirements in millions
of Btu/ton for various efficiency levels are shown in Table 7.
Table 7. HEAT CONTENT OF ALUMINUM WITH FUEL-
INPUT REQUIREMENTS FOR VARIOUS EFFICIENCY LEVELS
Heat Contents
Gross Efficiency, %
Temperature,
op
700
800
850
900
1000
Btu/lb
146
172
185
199
277
Net, 1000
Btu/ton
292
344
371
398
454
10
2.92
3.44
3.71
3.98
4. 54
20
-106 Btu/toi
1.46
1.72
1.85
1.99
2.27
30
0.97
1. 15
1. 24
1.33
1.51
Almost all convection reheat furnaces use natural gas because
of favorable price, controllability, and freedom from carbon depo-
sition or pollution-control problems. Atmosphere control is ini-
tially important for direct-fired furnaces, and the atmosphere is
most readily controlled with natural gas firing. In indirect heating
with radiant tubes, application of residual oil firing is extremely
difficult.
From the available data, it appears that the convection heaters
for forging and extrusion operate at very low efficiency level, pro-
bably averaging 10% to 15% overall. The major reasons for the low
efficiency level appear to be conveyor reheating, excessive air in-
filtration, and high flue-gas temperature from radiant-tube firing.
The most important single factor affecting efficiency is air infiltra-
tion. Convection-heating furnace designers estimate that 100% excess
air is heated because of leakage losses.
IV- 395
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About the only effective means for improving the efficiency of
existing convection-furnace designs using radiant-tube heating is
to install recuperative radiant-tube burner systems. A fuel saving
of 20% to 25% can be attained by preheating combustion air to the
650°to 750°F range.
Air Pollution Emissions From Primary Aluminum Manufacture
Information regarding air pollution emissions is very limited,
and then it is restricted primarily to discussions of fluorides and
particulates. No data are currently available on combustion-related
emissions from primary aluminum manufacturing processes. How-
ever, there is no reason to believe that these emissions will be any
different than those from similar processes in other industries.
Thus, it can be presumed that CO, hydrocarbons, nitrogen oxides,
and sulfur oxides are being emitted. The extent to which these
emissions are a problem remains to be determined.
The product of the secondary aluminum industry is a metallic
aluminum alloy in the form of 15 and 30-lb ingots, 1000-lb sows,
or hot molten alloy. Some scrap is melted to produce a deoxidizer
for steel mills in the form of a notched bar or shot.
The scrap raw material is purchased on the open market in
various forms. The scrap can be divided into two categories:
residues and solids. Residues include dross and skimmings from
melting operations in the primary aluminum industry, from fabri-
cators, and from foundaries. Dross, the scum that forms on the
surface of molten metal, is high in aluminum content. Solids con-
sist of borings, turnings, new clippings and forgings, old castings,
sheet, and castings containing iron.
The quantity of energy required to melt 1 pound of secondary
aluminum is about 5% of the amount required to produce the same
quantity of virgin aluminum from bauxite in the primary industry.
Depending upon the size and condition of the melting furnace,
IV- 396
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approximately 10, 000 Btu of energy is required per pound of product
produced, excluding the energy required to operate pollution control
devices.
Three basic operations are employed in recovering aluminum
from scrap materials: preparation prior to smelting; charging,
smelting, and refining; and pouring the product. The operations
vary among different smelters and result in a variance in the quan-
tity of energy required.
Presmelting varies according to the type of scrap. Solids are
sorted, sweated, dried, and reduced in size, and residues are reduced
in size and screened to separate the metal values from the conta-
minants. High-quality scrap consisting of forgings and new clippings
has very little contamination and usually is sorted only to remove
foreign metal.
Borings and turnings are heavily contaminated with cutting oils.
The material is received in intertwined pieces that are crushed in
ring crushers or hammermills. After crushing, the material is fed
into gas- or oil-fired rotary dryers to burn off oils, grease, and
moisture. The material then is screened to remove fines and passed
through a magnetic separator to remove available iron.
After pretreatment, the aluminum scrap is charged into rever-
beratory furnaces in a series of seven steps: 1} charging the scrap
into the furnace, 2) adding fluxing agents, 3) adding the required
alloy materials, 4) mixing, 5) removing magnesium, 6) degassing,
and 7) skimming. All these steps are not practiced by all smelting
operators, and the choice of steps depends upon the desired end
product.
The amount of time required to fully charge a furnace depends
upon its size, which can range from 10 to 90 tons. It takes from 4
to 75 hours to fully charge a furnace, the average time being 24 hours.
The time required to complete a smelting cycle depends upon the
size and design of the furnace, fluxing procedures, alloy require-
ments, and heat input.
TV- 397
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A typical secondary aluminum recovery plant consists of two to
four — sometimes as many as 10 — reverberatory furnaces which
are predominantly natural gas-fired. A furnace with a 40-ton name-
plate capacity rating may actually produce 20 tons of product per
heating cycle. Approximately one-third of the 10, 000 Btu/lb re-
quired in the smelting operation, as previously mentioned, powers
the auxiliaries, such as pretreatment of the scrap. The thermal
efficiency of a reverberatory furnace under optimum operating con-
ditions is 25$ to 35$ .
Although natural gas is the principal fuel in furnace operation,
oil can be an alternative with some modification in operating prac-
tices. The efficiency of the burner decreases when oil is used. The
reverberatory furnace operates by deflecting the flame onto the
charge by a sloping-roof arch. The burner is fired diagonally down-
ward toward the melter bottom against, or just over, the metal bath.
Combustion products vent at the opposite end of the furnace through
a combination hopper and flue. Much of the heat transfer occurs by
radiation from the roof and sidewalls of the furnace. The furnaces
can be fixed, tilting, or rotary, and a luminous flame is desirable,
although flame length can be a limiting factor, depending on burner
placement and furnace geometry. The efficiency decreases when oil
is used because a minimum distance is required to achieve atomiz-
ation and complete combustion.
Aluminum. Industry-Field Survey
The companies contacted during the course of this study con-
sisted of two primary producers and one secondary producer. The
major energy conservation steps undertaken by these firms can be
summarized as follows:
• Continuing research and development programs to improve
existing manufacturing processes
IV- 398
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• Streamlining production processes by modifying equipment
and operating practices
• Installation of energy management programs at all organiz-
ational levels.
These programs are the direct result of the current decreasing
availability of natural gas supplies to industrial users and increasing
oil prices. The increased use of coal, particularly for steam gene-
ration, is regarded as a near-term solution to the problem. A pros-
pective development anticipated for the long-term time frame is in-
creased development of nuclear power.
Approximately 52$ of the energy requirements within the pri-
mary aluminum industry is the form of electric power. This power
is generated internally as well as purchased from outside sources.
The two primary producers interviewed produced a major portion of
their power requirements internally.
The average power consumption of an aluminum smelter is about
8 kWhr per pound of aluminum produced from alumina. The most
efficient smelter requires about 6. 5 kWhr per pound.
Some of the newest developments within the industry include
the following:
• Flash calcining
• Electrolytic smelting
• Pulverized coal
• Preheating metal charge.
A flash calcining unit has been developed on a proprietary basis.
This system combines the benefits of the fluidized bed and dispersed-
phase technology to improve both heat exchange rates and to reduce
heat losses. The amount of energy consumed in a rotary calciner
to produce alumina is approximately 2000 Btu per pound of product.
Reportedly, the flash calciner requires 1400 Btu per pound of pro-
duct.
IV-399
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Electrolytic smelting, another process of a proprietary nature,
has been developed and reduces power requirements within the smelting
step by 307°. The process includes a reactor to react chlorine and
alumina to produce aluminum chloride. The aluminum chloride is then
electrolytic ally decomposed in a separate cell producing chlorine and
aluminum. The chlorine is then recycled back to the first stage reac-
tor.
Reverberatory melting furnaces are used both in primary and
secondary producing industries to remelt mixtures of scrap and pri-
mary aluminum. In the past, these furnaces have been fired with
natural gas and have been recently converted to residual oil because
of the natural gas shortage and uncertainties concerning future pro-
pane availability.
One of the firms is about to embark on an experimental program
wherein a pulverized coal combustion system will be installed on a
melting furnace. Successful development of a compact, efficient
process for SO2 removal from the stack gases would lend itself to
the establishment of coal as a primary fuel within the aluminum in-
dustry.
The average efficiency of fuel fired melters is in the range of
25% to 35%, dependent upon operating practice, age, and condition.
Preheating the metal charge and combustion air can increase fuel
efficiency up to as high as 50%. Melters fired with natural gas, pro-
pane or oil with an acceptable sulfur level do not require stack-gas
cleaning or scrubbing to meet existing pollution legislation. Conver-
sion to coal firing would require the installation of a stack-gas clean-
ing device for fly-ash removal. Solvent refined coal (SRC) which
has a very low ash content, could be used as a fuel in reverberatory
furnaces, if its price is competitive with the cost of residual oil or
coal, including the expense of stack-gas cleaning devices.
IV- 400
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From a practical sense, No. 2 fuel oil is easier for the furnace
operator to use than No. 6 oil. However, No. 2 oil is at the mercy
of fuel allocation programs, as is natural gas, and is subject to
extreme swings in availability.
The composition of No. 6 oil makes it difficult to handle in a
reverberatory furnace. The No. 6 oil available today is a blend of
tars and fluidizing agents that render it incompatible with good com-
bustion practice. The oil must be preheated to 190° to 200°F to
make it flow, and in this temperature range the blending agents
flash out. In addition, No. 6 oil must be used under high pressure
to achieve atomization; it has a high ash and sulfur content, is high
in particulates produced, and is costly in terms of storage require-
ments. The general availability of No. 6 oil also is of concern to
the secondary aluminum industry because it must compete for avail-
able supplies with the electric utilities. Moreover, refineries are
producing less residual oil because of higher yields of gasoline and
other light oils.
The cost of electricity as a fuel is 3 to 8 times greater than the
cost of natural gas or fuel oil. The average price paid for natural
gas in 1970 was 50«f to 60«!/1000 CF. Present natural gas prices
range from a low of 90^1000 CF in the Southeast to as much as $2. OO/
1000 CF in the Pacific region. The opinion was stated that the large-
volume industrial user is losing his favored position in the switch
from wholesale to retail natural gas pricing. During 1971-72, the
price of No. 2 fuel oil was 8tff/gal; currently, it is 32^/gal, with
further increases anticipated.
The primary means of controlling stack emissions within this
firm, and for many others in the industry, is stack afterburners.
The afterburners, which are fired with natural gas, consume appro-
ximately 2000 Btu/lb of product produced, in addition to the 10, 000
Btu required to produce 1 pound of aluminum. No. 2 fuel oil can be
used in the afterburner if natural gas is not available; however,
TV-401
-------
the Btu requirement of fuel oil is greater: 5000 Btu/lb of product
produced.
In applications requiring additional control, venturi scrubbers
or baghouses may be installed after the afterburner. The type of
unit depends upon the emissions. The scrubbers are used to remove
chloride and fluoride contaminants. After the material from the
scrubber has been evaporated, the product is a dry salt. The salt
presents an additional solid waste problem because many states do
not allow disposal in landfills without expensive preparation to pre-
vent leaching into substrata water. Some states do not allow the dis-
posal of salts of any kind in spite of extensive preparation steps.
The recycling of aluminum cans has become a growing source
of scrap for aluminum melters, amounting to 68 million pounds in
1973. Associated pollution control problems include the lacquer
coatings used on beverage containers and oil or lubricants on rolling
mill and die casting scrap. One of the firms interviewed proposes
the development of a selective oxygen injection system for melters
to provide a low energy system for pollution control.
Baghouses are used along with afterburners to control particulate
emissions. The amount of energy required to operate a baghouse
is equivalent to approximately one-half of the energy required to
operate the afterburner, or about 1000 Btu/lb of product produced.
Baghouses require extensive maintenance and are not effective for
the control of gaseous emissions. In addition, a potential fire hazard
exists in the use of a baghouse because of the high organic content of
the material collected. Disposal of the particulate matter collected
in a baghouse presents the same problem as the disposal of salts.
IV-402
-------
Petroleum Refining
Petroleum refining is largely accomplished by distillation separa-
tion into intermediate feedstocks and products. The intermediate
feedstocks require heating and thermal cracking or catalytic treat-
ing before separation of the desired products. This separation usu-
ally requires additional heating after the catalytic treatment or
thermal cracking.
Total refinery energy consumption amounts to around 10% of the
crude throughput. Most of this energy is consumed as fuel in fired
heaters. The amount of energy consumption depends largely on the
complexity of processing which takes place after the initial crude
distillation separation. Generally a gasoline oriented refinery will
have fuel consumption considerably greater than a distillate oriented
refinery. In the long run, the refinery output is controlled to meet
consumers demand. This demand is for high gasoline production
in the summer and fall seasons with high distillate fuel production
during the winter season.
Petroleum refining involves the use of fired heaters in many
operations beginning with initial crude distillation unit. On this unit,
separation is made by distillation of the crude oil into the fractions
which become the charging stock for the other operating units in the
refineries. In a typical fuels refinery these units are as described
briefly below:
Reforming Unit; On this unit the fraction of straight run gasoline
boiling above 160°-180°F is vaporized in a fired heater, desulfurized
over a catalyst, and relieved of the sulfur and light fractions. The
straight run gasoline is vaporized in another fired heater and routed
over a platinum-containing catalyst which reforms the approximately
45% naphthenes to aromatic s, which have a high octane. This gaso-
line is relieved of the light hydrocarbons, making it a finished gaso-
line.
Catalytic Cracker; The material boiling above kerosene in the crude
unit is routed to a cat cracker where it is cracked at 875°-9Z5°F to
make a variety of materials including gasoline, olefins for alkylation,
and distillate fuel.
IV- 403
-------
Delayed Coker; This unit is a high fuel consumer employing fired
heaters to heat the charge oil for distillation. The distillation bot-
toms are routed through another heater to coke drums where the
heavy fractions remain while coking. The unit produces gas, ole-
fins for alkylation, gasoline, distillate fuel and coke.
AUcylation Unit; The three and four carbon olefins and isobutane
are reacted in this unit to make alkylate, a mixture of seven, eight,
and nine carbon-atom compounds, which are widely branched to
give a very high octane gasoline. Separation of the reaction products
is by distillation towers reboiled by a fired heater.
Distillate Hydrotreaters: These units are supplied with hydrogen
and the feedstocks heated in fired heaters to 650°-750°F before
routing over a fixed bed of catalyst for desulfurizing and upgrading
the burning qualities of the distillate fuels.
In most existing refineries the different units are operated as
separate entities having intermediate tankage for charge and products.
This provides both operating and maintenance flexibility. Trends
have been to eliminate the intermediate tankage and reduce fuel con-
sumption by running hot feed from one unit to another. New refiner-
ies can be designed in this manner to effect savings in fuel consump-
tion while accepting the risks of intermediate processing bottlenecks
or reduced stream factors. The completely integrated refinery can
have no greater on-stream factor than the lowest of the stream fac-
tors of the individual units.
The approach to developing information on trends in refinery
fuels consumption was to interview the fuels and emission coordina-
tors in the central office of the refining companies. Two of the
largest refiners were interviewed. These refiners have fourteen
refineries running a total of 1.7 million barrels per day of crude
oil. Also interviewed was the director of refining of the American
Petroleum Institute (API), who is responsible for setting up a fuel-
conservation program involving more than 80% of the U.S. refinery
capacity.
IV-404
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His program resulted in the naming of a fuel-conservation
coordinator *or each of the refining companies. A program for fuel
conservation was implemented for which results have become avail-
able.
These results have been reported as follows:
Energy Consumption,
weighted average for
37 companies,
1000 Btu/bbl input
1972 Base Period Total Energy
Consumption
1972 Base Period Adjustment to
1974
Adjusted 1972 Base Period Total
Energy Consumption
Less 1974 Last Half Year Total
Measured Energy Consumption
Energy Conservation Improvement
for last half of 1974
% Reduction from 1972 Base
667
+9
676
624
52
It is generally accepted that the greatest single factor affecting
the refining industries' improvement in fuel consumption was the
response of the industry to the economics of the high price of crude
which occurred during the last quarter of 1973 and the resultant
higher price of fuel consumed. One of the companies interviewed
arbitrarily set a fuel price for conservation economics to reflect
its selling price as fuel oil rather than the price of purchased
natural gas, which continued to be much below the more realistic
price of refinery fuel oil.
Effort to improve fuel consumption involved giving increased
attention to the current practices in firing the process heaters and
boiler house. In the larger refineries, checking of heating
IV-405
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performances and assisting the operators to achieve correction to
proper firing conditions is a full time job for one man. Firing to
10% excess air was accepted as a goal for furnaces firing gaseous
fuel, with 7.0% excess air for furnaces firing predominantly oil fuel.
Improved oxygen analyzer installations are being employed to monitor
this. These goals were not being attained, and it was felt that im-
proved fuel oil burner design would be required to accomplish this.
They feel that most existing furnaces lack the combustion space to
burn predominantly oil without a reduction of furnace throughput.
Preheat of the heater feeds is being given increased attention
in both existing and new installations. Cleaning of heat transfer sur-
faces in exchangers and heaters both on-stream and off-stream is
getting increased attention. Some novel techniques being applied to
fired heaters are:
1. Use of water lance for shock cooling and flaking deposits from
outside of tubes
2. Use of walnut shells for blasting of powdery deposits from out-
side of furnace tubes.
Increased maintenance of insulation on hot lines and increased
attention to required operating reflux ratios on distillation columns
are being employed in existing installations.
Refining organizations hope for continued improvements in fuel
conservation by long-range projects, both of a replacement nature
for existing equipment and in the installation of new units having the
benefit of improved design.
A comparison of past practice with future design practice shows
how the furnace design conditions will be tightened up.
Lowest temperature for heat
removal by exchange
Furnace stack-temperature
Past
Practice
400°F
800°F
Future
Designs
250°F
400°F
V- 406
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They recognize that furnace tube outside skin temperature will
be a consideration for the future designs as they will have to keep
surfaces above the dewpoint of the furnace gases.
Conservation coordinators feel that retrofit installations of air
heaters and steam, coils can be justified at current high fuel prices.
In completely new installations they will expect to have a greater
ratio of convection surface to radiant surface. Increased use of ex-
tended surface convection furnace tubes is expected. One group
favored a furnace design that will eliminate the damper in the
breeching to the stack, using instead an air supply box servicing
multiple burners. Such installation would provide dampers on the
forced air supply to the windboxes. They do not expect to be
going to flue-gas recirculation for emissions control.
The API refinery survey showed that 31% of the refinery fuel
consumed was purchased natural gas. Replacement of this gas with
liquid fuels will require more furnace volume, as mentioned above.
Some instances of conflicts between lower emissions and fuel
conservation were cited. In the interest of improving heater effi-
ciency they are going to air preheat. However, they are concerned
that NO standards which might be set in the future will put them
above the NO standard. In another instance, when lower stack
2C
temperature is achieved in the interest of improved fuel efficiency,
it can be calculated that ground-level emissions will increase. It
makes no sense to forego such installations in order to meet ground-
level emissions standards. In another instance, installation and
operation of Claus tail-age cleanup units unquestionably results in
high energy consumption but with no compensating improvement in
overall efficiency.
The refineries arc removing H2S from their major fuel-gas
streams. In so doing they are eliminating SOa emissions from the
heater stacks. By installing a Claus unit to convert the H2S to free
V- 407
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sulfur, they undertake a large expenditure for which, there is little
or no return. This is accepted without question as they recognize
that 95% of the sulfur emission is thus eliminated. However, the
remaining 5% of the sulfur is now going up a single stack. It re-
quires an expenditure equal to or exceeding the Glaus unit expenditure
to recover the remaining 5% of the sulfur. Furthermore, the Glaus
stack-gas recovery unit adds increased investment and labor costs
with practically zero return.
Recommendation by Refiner s
1. That emission guidelines be sufficiently flexible so as to allow
waivers for refineries in areas remote from cities. This prac-
tice is in the interest of fuel conservation.
2. That guidelines be set by environment tolerances rather than a
specification based on the refiners or a process1 capability.
3. That fuel oil burners be improved so as to allow combustion with
lower excess air.
rv-408
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APPENDIX A
Weighting Factors
The next step in the selection process is the assigning of weight-
ing factors to each of the restraints in terms of their relative import-
ance. In developing the weighting factors, the following assumptions
have been made:
1. All air pollutants arc equal in importance.
2. Conservation of energy and reduction of emissions are equal
in importance.
3. Industries with no potential for energy conservation or reduction
of emissions will be excluded from consideration.
Given these assumptions, the weighting factors are assigned based
on a scale of 1 to 1 0 where 1 is a low-priority and 10 is a high-
priority rating. To determing the suitability of a particular industry,
the following set of numerical operations would be performed:
1. Base energy consumption X emission index number — emission
weighted base number.
2. Estimated potential for energy conservation X emission weighted
base number.
3. Estimated potential for reducing emissions X emission weighted
base number.
4. Items 2 + 3 — conservation and emission weighted number.
Based on the value obtained in 4 above, the industries for study have
been selected with the highest value given the highest priority.
Table A-l defines the weighting system we used to arrive at the
numbers used in the above set of equations.
i V- 4()9
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Table A-l. WEIGHTING SYSTEM FACTORS
1. Base energy number
The base energy number is arrived at by summing the weighting
factors for restraints Nos. 1, 2, and 3, where the following values
are assigned (scale 1 -> 10).
Restraint No. 1. Energy use in process heat
1 = Low usage; 10 = High usage
Restraint No. Z. Combustion-related uses
1 = No combustion-related uses; 10 = All combustion-related uses
Restraint No. 3. Number of processes
1 = Numerous processes; 10 = One process only
Z. Emission index number
The emission index number is arrived at by summing the
weighting factors for restraints Nos. 4 and 5. However, since the
primary emissions of concern as indicated in restraint No. 5 are
generally directly combustion-related, the emission index number
can be based on restraint No. 4 alone with values assigned as follows:
1 = Mostly independent emissions; 10 = mostly combustion-
related emissions
3. Potential for energy conservation
1 = Low potential; 10 = High potential
4. Potential for reducing emissions
1 = Low potential; 10 = High potential
1V-410
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POM AND PARTICULATE EMISSIONS FROM
SMALL COMMERCIAL STOKER-PLRED BOILERS
By
R. D. Giammar, R. B. Engdahl, and
R. E. Barrett
BATTELLE
Columbus Laboratories
Columbus, Ohio
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POM AND PARTICULATE EMISSIONS FROM
SMALL COMMERCIAL STOKER-FIRED BOILERS
By
R. D. Giammar, R. B. Engdahl, and
R. E. Barrett
ABSTRACT
This paper describes a program to evaluate emissions, including POM
from residential and small commercial stokers. The program consists
of: (1) a survey to identify processes for manufacturing smokeless
coal and to evaluate the suitability of these fuels for stoker-
firing; (2) a survey to identify the manufacturers and designs of
small stokers currently being marketed; and (3) an experimental
laboratory program to measure emissions while firing a small stoker
with several candidate stoker fuels. In the experimental program,
a 20-horsepower stoker-fired boiler is fired with anthracite,
bituminous, Western and "smokeless" coals over several operating
cycles. From the results of these experiments and the survey, a
program will be recommended to increase environmental acceptability
and to improve the economics of residential and small commercial
stoker boilers. The experimental portion of this program is
currently being conducted and, as a result, data are not available
for discussion.
TV-4 12
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POM AND PARTICULATE EMISSIONS FROM
SMALL COMMERCIAL STOKER-FIRED BOILERS
By
R. D. Giammar, R. B. Engdahl, and
R. E. Barrett
INTRODUCTION
Coal was still a major fuel fired in residential and small
commercial heating systems as late as the 1950's. Coal usage then
rapidly declined as the market area of the less expensive and more
conveniently fired fuels, gas and oil, expanded. Even in certain geo-
graphical locations where coal was cheaper than oil or gas, the high
maintenance costs and labor associated with firing coal coupled with
an increased awareness of the environment virtually eliminated the
use of coal for residential and small commercial space heating appli-
cations by the 1960's.
However, the uncertainty in both the short- and long-term
availability of oil and gas has created renewed interest in burning
coal to meet our nation's energy needs. In order to technically assess
the environmental impact of burning coal, specifically in residential
and small commercial applications, the EPA has funded a program to
evaluate the emissions from these units under smokeless operation.
This program consists of:
(1) A survey to identify the manufacturers and designs of stokers cur-
rently being marketed. Because the design and operation of small
TV-413
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stokers is almost a lost art, a discussion of design and opera-
tional aspects are included in this survey.
(2) A survey to identify processes for the manufacturing of smokeless
coal and to evaluate the suitability of this fuel for stoker firing.
(3) An experimental laboratory program to measure emissions while
firing a small stoker with several candidate fuels.
This program is ongoing as experimental data are currently being ob-
tained. Accordingly, the results of the laboratory work are unavail-
able for publication at this time, but will be included in the final
report on EPA Contract No. 68-02-1848-
OBJECTIVES AND SCOPE
The overall objectives of this program are:
(1) To evaluate emissions from residential and small commercial stoker-
fired boilers under typical boiler operation, including smokeless
operation.
(2) To assess the advisability of increased utilization of coal for
residential and small commercial applications including considera-
tion of operating efficiency, fuel type and availability, economics,
and environmental impact.
A 20-hp stoker-fired boiler system is being used to evaluate
emissions from the combustion of anthracite, Western, processed "smoke-
less", and high- and low-volatile coals under several boiler operating
cycles. Pollutants of interest include NO, S02> smoke, particulate,
and the polycyclic compounds.
IV- 414
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TECHNICAL BACKGROUND ON STOKERS
To provide a basis for an assessment of the increased utili-
zation of stokers, a description of the design and operation of stokers
is given to identify the complexity (in contrast to oil and gas) of
burning coal in small units. Also, a summary of the survey of stoker
manufacturers is included.
Stoker Design and Operation
Smoke evolved when burning high-volatile coal has always
been a problem for residential and small commercial heating units.
Development of the residential underfeed stokers, such as the inverted-
underfeed stoker designed in the 1940's, made it possible to burn high-
volatile coal smokelessly. However, recent attention has focused on
all emissions which includes not only smoke, but NO , SO , CO, particu-
X X
late, and POM. Levels of these emissions are related to stoker design,
stoker operation and firing procedure, and the type of coal burned.
These aspects are discussed below.
Stoker Design
The small mechanical stokers in the range of interest are of
the underfeed type. The underfeed stoker with a worm-feed mechanism
is normally used to feed coal at rates up to 1200 Ib/hr. In contrast
to handfiring or spreader stokers, underfeed stokers supply fresh coal
IV- 415
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to the boiler or furnace by feeding it underneath the hot coals. This
stoker consists of a retort, fan, motor, transmission, air duct, air
duct control, hopper and feed screw. Figure 1 is an illustration of a
typical stoker assembly.
Motor and Transmission. The underfeed stoker is driven by an
electrical motor, usually mounted on top of the transmission. The motor
drives the transmission through V-belts. Various electrical devices
control the operation of the motor including room thermostat, boiler
limit switch, and the hold-fire timing relay. The transmission rotates
the coal-feed screw at a speed determined by the capacity of the heat-
ing system. Feed rates can be varied by changing the motor or trans-
mission pulleys.
Feed Screw. The feed screw conveys the coal from the hopper
to the retort, or with a bin-fed type, directly from the coal bin to
the retort. The feed screw extends from the coal supply (hopper or
bin) through the worm-tube into the retort, where it discharges the
coal it conveys.
Retort. The retort is a cast-iron chamber in the shape of a
cup or trough in which the coal is ignited and the volatile gases are
driven off. The retort is surrounded by a windbox and contains slotted
holes for admitting air under slight pressure to the fire. These slot-
ted holes, or air admitting ports, are often referred to as the tuyeres.
IV-416
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Because anthracite differs in combustion characteristics from
bituminous coals, a different retort design is required to burn this
coal successfully. The bituminous retort is built to burn a coal re-
latively high in volatile matter and to fuse ash into a removable
clinker; the anthracite stoker retort, on the other hand, is built to
burn coal of low volatile content and to spill ash into a pit or to the
receiver for the ash. Also because anthracite burns with a slow uni-
form flame, it requires less combustion space than bituminous coals.
Fan and Air Control. Fans for supplying combustion air in
the underfed stokers are usually squirrel-cage types that provide
relatively high pressures and low volumes. The fan is equipped with
either a manual or automatic damper to regulate air flow. The fan
develops sufficient static pressure to overcome a series of resistance
generated by flow through the fuel bed, tuyeres, air ducts and regu-
lating damper.
Stoker Operation
The residential and small commercial stoker-boiler operate
basically the same in principle although their operating cycles can be
different depending upon application. Characterization of the opera-
tion of these units is complicated because they seldom operate with a
steady-state heat-release rate.
V-417
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Off-On Cycle. Figure 2, a plot of CO levels as a function
of time, illustrates the nonsteady heat-release rate of stokers. Units
of this size operate in an off-on cycle, the time in each mode related
to the load. During the on-cycle, fresh coal is fed underneath the hot
coals and air is admitted through the tuyeres. The heat-released rate
increases substantially as the coal bed temperatures gradually increase,
but often not reaching a steady-state temperature before the thermostat
stops the stoker screw and fan. The heat-release rate is then reduced
drastically, but the bed continues to burn, being supplied by minimal
quantities of air by the natural draft. At this time unburned hydro-
carbons can be released because of insufficient air. Figure 3 shows a
typical plot of retort and stack temperatures during an overnight run
of a stoker on a 10-minute on and 50-minute off cycle.
Full-Load and Hold-Fire Operating Cycles. There are two ex-
tremes in stoker-boiler operation, namely, full-load and no-load.
During full-load operation, the stoker is running continuously; however,
the stoker is stopped for at least 5 minutes in every 30-minute cycle
so that bed temperatures cool and the ash fuses*. If not given an op-
portunity to cool, certain coals will remain fluid and sticky with re-
sulting nonuniform feeding and irregular burning of the large caked
masses.
* This off cycle can vary with ash content composition of the fuel.
Anthracite with a low ash content and high fusion temperature can
be burned continuously with no off period.
IV-418
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During the no-load period, the boiler operates in a hold-fire
period of operation. Thus, the stoker is kept alive by short starts
to keep the fuel bed sufficiently alive to respond quickly when the
boiler load increases. The typical hold-fire period for bituminous
coal is approximately a 5-minute operation of the stoker in each 30-
minutes;* otherwise the fuel bed temperature will be too low to ignite
fuel that enters the retort during the on-period.
Partial load operation falls in between these extremes. The
stoker always feeds at a constant rate and adjusts to varying loads by
varying the on time in each cycle of operation.
Coal Classifications
Selection of stoker coals is of paramount importance in suc-
cessful stoker operation. Proper stoker adjustments for smokeless
operation are largely dependent on the coal analysis and coal size.
For instance, unsatisfactory stoker operations occur if
• a large percentage of fines restricts the amount
of air that reaches the fuel bed
• a high percentage of ash results in troublesome
clinker formation
• a low ash-fusion point coal creates clinkers that are
difficult to remove from the stoker as the ash may
melt and fuse or stick to the tuyeres.
* The hold-fire period for anthracite can be as low as one minute
every half hour.
IV-419
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Accordingly, the most desirable coals for small stoker opera-
tion are relatively free-burning, low-volatile, and low-sulfur coals
that are sized 3/4 x 1/4. The free-burning coals include all coals
that neither cake nor coke.* These coals burn to a fine ash and do not
restrict air flow through the fuel bed. Low-volatile coals tend to
burn slowly with a uniform flame and as a consequence do not generate
appreciable levels of smoke over the entire stoker operating cycle.
Finally, sulfur oxide levels are related to the sulfur content of the
fuel, and thus, the low-sulfur coals are the most desirable.
Among coals that have been commonly marketed in the United
States for residential and small commercial stoker applications include
anthracite, bituminous and Western or sub-bituminous. In addition, a
smokeless coal has been commercially developed and has been used in
England, although not for mechanical stoker firing, A brief discussion
of these coals as related to stoker firing is given below.
Anthracite. Anthracite is a desirable coal for coal firing
because it is a free-burning, low-volatile, and low-sulfur coal.
Host anthracites have ash-fusion temperatures above 2700 F which per-
mits the ash to spill over the retort into a pit or into a conveyor
trough for ash removal. This property makes anthracite stokers adapt-
able to a continuous modulation mode of operation rather than an off-
on cycle. Being low in volatile content, it burns slowly and uniformly
* Caking coals emit tars and swell when heated; coking coals do not
swell when heated but emit tars.
IV-420
-------
with a compact flame allowing a smaller combustion chamber than bitumi-
nous coal. In addition, because anthracite is a hard coal, it does
not degrade (in size) during handling and shipping.
Bituminous. Bituminous has been a widely used coal for
stoker firing because it is found near population centers. There is a
wide range in the analysis of bituminous coals but it generally con-
tains 25 to 50 percent volatile matter, 7 to 15 percent ash, and 2 to
4 percent sulfur. This coal has been fired successfully in stokers
but requires precise air adjustments and routine maintenance.
Western Subbituminous. Western subbituminous coals have not
been widely used for stoker application; although in some local regions,
like Salt Lake City where it is readily available, significant quantities
have been burned for residential heating. In general, these coals
have high moisture (frequently as much as 50 percent), high ash (10
percent), and low ash fusion temperatures. Because Western subbitumi-
nous coals tend to degrade easily and have low heat content, their
market area has been restricted to regional usage. However, they do
have low sulfur content which makes them environmentally attractive.
Processed Smokeless Coal. The analysis of processed smokeless
coal indicates that its composition is ideally suited to stoker firing.
This coal, however, as manufactured would present problems in feeding
with conventional stokers; the coal is extremely hard and was produced
in sizes typical of the present day charcoal briquet.
IV-421
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Smokeless Combustion
Smoke is a suspension of small solid particles in flue gases
discharged during the burning of fuel. The particles are of two types--
unburned residues of carbon formed by decomposed volatile material from
the fuel, and ash remaining after the fuel is burned.
Any fuel may be burned smokelessly at suitable temperatures
with enough oxygen, good mixing, and sufficient time to complete the
combustion. It is important to burn the volatile matter completely and
rapidly to avoid soot or carbon formation. Carbon smoke particles formed
by decomposition without oxygen are difficult to burn, and usually are
lost as smoke.
A high volatile coal may give off as much as 35 percent of
its weight as combustible vapors and gases when it is heated. Rapid
heating causes rapid evolution of volatiles which then requires a high
rate of air supply and rapid mixing to permit complete combustion.
Even with sufficient air and complete mixing, there are situations in
which the temperature is too low to ignite the combustible mixture.
In one such instance the coal may be added to a cool fuel bed where
there is no hot spot to ignite the tars and gases as they slowly dis-
till. In another, the vapors and air may be adequately mixed at a suf-
ficient temperature, but they may pass out of the combustion zone
IV-422
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and be quenched by the cool surfaces in the boiler and flue. Any of
these deficiencies result in carbon particles and condensed tar drop-
lets that appear as smoke. In summary, the requirements for smokeless
combustion are temperature for ignition, turbulence for mixing, and
time for completion of combustion reactions.
Any fuel with a volatile content of up to 25 percent by
weight will burn smokelessly when a few precautions are taken to pro-
vide the necessary temperature, turbulence, and time in the combustion
zone. This tendency for smokeless combustion follows from the lower
requirements for combustion air to burn the volatiles. Higher pro-
portions of air are available to burn the solid carbon in the fuel bed
(which produces a hotter bed) and less mixing and time are required
for complete combustion in the gas phase above the solid fuel bed.
POM Generation
The term POM, polycyclic organic matter, is used variously,
depending on the scope of the material compositions being considered.
Thus, chemically, the term POM includes all polycyclic compounds; hydro-
carbons, heterocyclic compounds, and chemical derivatives such as acids
and alcohols that can be derived from them. Among these are several
compounds of great concern because of their potential carcinogenicity.
IV-423
-------
Available data are not suffucient to provide an accurate
quantitative statement of POM emissions from residential and small
commercial stoker-fired units. However, the potential exists for sub-
stantial yields of POM because of the chemical composition of stoker
coal and the manner in which these stokers are typically operated,
particularly during the first phase of the "off" period.
Chemical Composition of Coal. Coal is composed of high-
molecular-weight compounds that are more difficult to burn out than in
the lower molecular hydrocarbons found in the fluid fuels. These higher
molecular weight compounds if only partially destroyed by the flame
provide a "building block" from which the large ring structure hydro-
carbon can be formed, some of which are carcinogenic.
Stoker Operation. It has been observed that POM are gener-
ated by pyrolysis in the preflame zone of a burner at above 550 C, and
the concentration of individual POM rise with increasing pyrolysis
temperatures up to a critical value of about 750 to 800 C. With further
increases in temperatures, the concentration falls again due to the
onset of the decomposition process. The POM formed by pyrolysis in
the preflame zone is destroyed as the vapors enter the hottest portion
of the flame and then gradually reformed in the falling temperature
portion. As described early, the off-on cycle of stoker operation with
low fuel-bed temperature gradually building up to a peak and then fall-
ing again appears conducive to POM generation.
IV-424
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Stoker Survey
The findings from the survey of over twenty present or past
manufacturers (or their representatives) of residential and small com-
mercial stoker-fired space heating equipment include:
• Residential and small commercial stoker-boilers are
similar in design as systems components are scaled
(up or down) to match the desired range of operation.
The stokers are of the underfeed type.
• The conventional underfeed bituminous stokers are
capable of firing most coals except anthracite.
• The conventional underfeed anthracite stokers are
designed to fire anthracite only. There is a pos-
sibility that this stoker could fire "smokeless" or
processed coal if properly sized.
• There is only one manufacturer of the conventional
bituminous stoker in the size ranges of interest.
Domestic sales are about 500 units/year.
• There is only one manufacturer of the conventional
anthracite stoker. Sales are less than 20 units/year.
One additional manufacturer makes an anthracite stoker
that is an integral part of the boiler system.
IV-425
-------
• There are only three major manufacturers (H. B. Smith,
Kewanee, and Weil McLain) of boilers for stoker firing.
Of these, only Weil McLain currently manufactures a
boiler in the residential size range.
• There are over 200,000 living units heated by anthracite
coal. Most of these units are hand-fired.
• There has been renewed interest in stoker firing in the
size ranges of interest. The majority of activity has
been for small commercial applications rather than
residential.
t The majority of the new stoker-boiler systems are de-
signed for hot water, while most replacements are for
steam systems. There has been some renewed interest in
residential stoker-fired warm air furnaces.
IV-426
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EXPERIMENTAL PROGRAM
A 20-bhp stoker-boiler facility including provision for
stack sampling was installed. Initially, emissions will be measured
utilizing the bituminous stoker capable of firing high- and low-vola-
tile bituminous coal, a processed smokeless coal,* and a Western sub-
bituminous coal. Later in the program, an anthracite stoker will be
installed to fire the anthracite and possibly the processed smokeless
coal.
includes:
Experimental Facility
Figure 4 is a photograph of the overall system layout that
• Kewanee 3R-5 20-bhp (200 kw), fire-tube, hot-water boiler
• Will-Hurt 75 Ib/hr (34 kg/hr) bituminous stoker
• 14-inch (0.35 m) diameter stack section
• Sampling platform.
* The processed smokeless coal is a lignite char briquet with a corn-
flour binder.
IV-427
-------
A Van Wert 60 Ib/hr (27 kg/hr) anthracite stoker (not shown) can also
be mated to the boiler.
Approximately 10 pipe diameters above the boiler stack-gas
outlet, 4 sampling ports are installed. These ports are utilized to
sample over the discrete time periods of stoker-boiler operation.
Approximately 5 feet above the sampling ports a damper is installed
to provide a control of the draft at boiler outlet. Provision for
smoke and gaseous-emission sampling ports are provided at the base of
the stack in addition to several ports for temperature and pressure
measurements.
Fuel Analysis
Table 1 lists some properties of the coals that will be
fired during this program. The analysis are reported on an "as received"
basis and included the moisture content of the coals. This moisture
content, can vary randomly from day-to-day depending on climatic con-
dition, and is also dependent upon washing procedures used at the mine.
IV-428
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In general, however, the moisture content gives a measure of the inherent
moisture content of the coal. The free swelling index is a measure of
the caking properties of the coal as indicated by high values of the
caking bituminous coals. The processed smokeless fuel is a lignite
char briquette.
Characterization of Boiler Operation and POM Sampling
The operating cycle of a stoker-boiler creates a unique
problem in obtaining meaningful emissions data. As discussed earlier,
the stoker seldom operates at a steady-state condition. Transients
occur not only during the starting and stopping of the stoker but
throughout each "on" and "off" period of operation. In addition, and
most importantly, during the "off" period, the fuel bed continues to
burn as a sufficient amount of air is supplied by the natural draft of
the stoker-boiler system.
potential Experimental Runs
Initially, the stokers will be fired on several coals and at
several boiler loads to establish potential operating conditions for
the POM and particulate sampling. Listed below are 6 potential coal-
stoker combinations to be investigated. In addition, the boiler will
be operated at four loads for each of the coal-stoker combinations.
Possible boiler loads to consider for a 60-minute operating cycle include:
IV-430
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On
10 min
20 min
40 min
50 min
Continuous
Off
50 min
40 min
20 min
10 min
(Anthracite only)
Accordingly, there is a potential of 24 operating conditions of which
8 will be selected for POM and particulate measurements. In an investi-
gation of emissions from small commercial oil- and gas-fired furnaces
a load factor of 1/3 was used (10-minute on/20-minute off cycle). Ac-
cordingly for comparison purposes, the 20-minute on/40-minute off cycle
could be selected as the basic cycle to evaluate the emissions from
the firing of each coal.
Stack Probing
For the 8 conditions, the boiler stack will be probed to
generate transient temperature and velocity profiles. In addition,
for the bituminous-coal stoker combination, transient velocity and
temperature profiles will be generated for several boiler loads.
IV-431
-------
Hot wire anemometry will be used to characterize stack flow
as a function of time. Two probes will be used simultaneously. Probe
1 will be located approximately 2 feet (.6m) between the sampling port
and contain a hot wire sensor set stationary on the centerline to
monitor axial flow velocity with time. In addition, a thermocouple
will be attached to Probe 1 to monitor temperature with time. These
data will be used as a baseline measurement.
Probe 2, to be located at the sampling port, will contain a
traversing hot wire sensor used to determine the radial velocity pro-
file as a function of time. Initial traversing measurements will be
made to establish the importance of swirl and temperature with respect
to radial position. An existing traversing mechanism is currently being
modified to accommodate the needs of this specific task.
Also, a correlation will be established to relate measure-
ments of Probe 1 with Probe 2 so that meaningful undisrupted flow
monitoring can be conducted during sampling. All hot wire sensors are
quartz-coated hot film sensors, Model No. 1210-20 with an instantaneous
response time.
POM Sampling
The transient stack-probe data will be analyzed to relate
these profiles to stoker cycle operation. The transient stack-probe
, data will be integrated to determine an appropriate POM probe position
(within the stack) and pumping rate for the time segment under con-
sideration .
IV- 432
-------
Analysis of the POM samples will include, for example, the
( 2 )
three- and four-star compounds assessed by NAS as carcinogenic:
9,10 - Ditnethylbenz(a)anthracene
3 - Methyl chloanthrene
Benz(a)pyrene
Dibenz(a)anthracene
Benz(c)phenanthrene
Dibenz (c ,g)carbazole
Dibenz (a,i)pyrene
Dibenz(a,h)pyrene.
After analysis of these samples, data will be compiled into
a composite picture of transient POM emission and integrated to yield
the gross out-put levels. On-line gaseous and smoke emission data will
be taken during these evaluation runs to assure a degree of repeat-
ability in the experimental program. These data will also be compiled
and integrated to yield the transient and time-averaged emissions.
Analytical Procedures
Partlculate and POM sampling and analytical procedures (modi-
fied EPA Method 5 train with an adsorbent column) have been described
( 3 )
by Jones and Giammar . Gaseous emissions were determined by: para-
magnetic analysis for oxygen; flame ionization detection for unburned
hydrocarbons; nondispersive infrared for carbon monoxide, carbon
dioxide, and nitrogen oxide; and a dry electrochemical analyzer for
IV-433
-------
sulfur dioxide. Smoke emissions were determined with a Bacharach smoke
tester according to the ASTM filter-paper method for smoke measure-
ments .
REFERENCES
(1) Barrett, R. E., Miller, S. E., and Locklin, D. W., "Field
Investigation of Emissions from Combustion Equipment for Space
Heating", EPA-R2-73-0846 and API Publication 4180 (1973).
(2) "Polycylic Particulate Organic Matter", National Academy of
Sciences, Washington, D.C. (1972).
(3) Jones, P. W. , Giammar, R. D., Strup, P. E., and Stanford, T. B,,
"Efficient Collection of Polycyclic Organic Compounds from
Combustion Effluents", presented at the 68th Annual Meeting of
the Air Pollution Control Association, Paper No. 75-33.3,
Boston, June 15-20, 1975.
(4) Standard Method of Test for Smoke Density in the Flue Gases
from Distillate Fuels, ASTM Designation: D 2156-65
(Reapproved 1970).
IV-434
-------
FIGURE 1. CONVENTIONAL STOKER ASSEMBLY
(Side illustration showing
various parts:
1. Hopper
2. Electric motor
3. Transmission
4. Coal feed tube
5. Feed worm
6. Retort
7. Clean out opening
8. Retort air chamber. Fan is partially
hidden by the transmission and motor
IV-435
-------
CL
O
o
o
o
o
o
0)
E
o
o
CVJ
O
O
6
4
O
O
o
CVJ
00
I
OT iJ
W O
JS IS
cu o
E ?^
Cti FH
O H
M
H
fi
O O
2
CM
oi
IV-436
-------
Time
c
O
o
55
o
.
o
GO
c
6
Tl
lOmin
50m in
10 min
50min
10 min
JU
200
\
\
Retort temperature
Stack temperature
300
400 500
Temperature, F
600
700
FIGURE 3. TYPICAL PLOT OF RETORT AND STACK TEMPERATURES
DURING AN OVERNIGHT RUN OF A STOKER
IV-437
-------
FIGURE 4. STOKER-FIRED BOILER FACILITY
IV-438
-------
2: 20 p.m.
POM and Particulate Emissions
from Small Commercial Stoker-
Fired Boilers
Robert D. Giammar, Battelle, Columbus Laboratories
Yesterday you presented some data on POM in gas and
oil combustion systems and today in coal. Have you
done any detailed analysis on any of your samples
for distribution among the different species? Have
you seen any differences between the three types of
fuels?
Yes. We have. We are looking at 13 POM species.
Some of these as rated by the National Academy of
Science are ranked as 1-4 stars, where the 4 star
has the highest potential for cancer-forming hydro-
carbon. On the other question, the distribu-
tion of the POM species is different for coal in
comparison to oil or gas. For oil and gas, appreciable
quantities of pyrene and fluoranthene, both considered
innocuous, were observed while very little B(a)P and
other 3 and 4 star compounds were observed. With the
oil and gas, we see essentially four innocuous
species that comprise 99% of the total POM catch.
With coal we have seen a wider distribution. We
have identified 10 species, some of which are 3- and
4-star compounds contained in significant levels.
About the report you gave yesterday, and it is
probably appropriate here,would you comment about the
sampling technique that you used and how that
technique differs from the normal method five?
The sampling technique used is quite similar, if
you are familiar with the method 5. We insert
IV- 439
-------
what we call an absorbent sampling device or a column
packed with Tenax material in between the hot filter
and the impingers. We then can use the probe wash
and the filter catch to measure a total particulate;
and we use the probe wash, the filter catch, and
what is found in the packed column for our POM
determination. Earlier studies indicated most of
the POM was found in the packed column rather
than in method 5 components. Another co-worker
at Battelle and I presented a paper at APCA in
Boston in June, describing the technique.
IV- 440
-------
CONCLUDING REMARKS FOR
STATIONARY SOURCE COMBUSTION SYMPOSIUM
by
Joshua S. Bowen
Environmental Protection Agency
Combustion Research Branch
Industrial Environmental Research Laboratory-RTP
Research Triangle Park, N. C.
IV-441
-------
CONCLUDING REMARKS FOR
STATIONARY SOURCE COMBUSTION SYMPOSIUM
The Combustion Research Branch of EPA's Industrial Environmental
Research Laboratory, RTF has sponsored this symposium on stationary
source combustion as one of a series of similar meetings aimed at infor-
mation exchange or transfer.
Early emphasis of our Combustion Control Program was directed
to research and development of economical and efficient combustion modi-
fication techniques for controlling air polluting emissions of nitrogen
oxides, combustibles (e.g., carbon, carbon monoxide, unburned hydrocarbons),
smoke and particulate matter from major stationary combustion sources
burning a variety of conventional and alternate fuels. More recently with
the structuring of our Utility and Industrial Power Program, the emphasis,
although still strongly aimed at control of NO and combustibles, has been
expanded to encompass consideration of pollution from a multi-media view-
point and to look at a broader range of potential pollutants, including
hazardous pollutants, trace materials and others.
An earlier seminar in June 1973 was devoted entirely to coal combustion
discussions. During the intervening period significant technical
advances have been made on so many fronts that it appeared worthwhile to
cover our entire program in the present meeting. Consequently, an agenda
was arranged in which investigators on most of the research and development
projects comprising the NO Control portion of the overall program were
X
IV-442
-------
asked to present their up-to-date results. Since the meeting was intended
not only for the dissemination of technical information among the investiga-
tors involved in our program, but was also planned for the exchange of
ideas concerning the technical experience and related data of others,
many representatives of industry, Government and the academic community
were asked to attend.
The specific purpose of the meeting then has been to review and to
exchange information on the Combustion Research Branch's in-house and
contracted studies aimed toward the development of practical combustion
modification technology for the control of NO and other combustion-
generated pollutant emissions from major stationary combustion sources.
For purposes of presentation the papers were grouped into sessions
corresponding to the major subheadings of the NO Control program.
X
These categories were: fundamental research, fuels research and develop-
ment, process research and development, and field testing and surveys.
To recapitulate very quickly the symposium has included the following
subjects.
Discussions in the fundamental research area have covered the
study of the mechanisms and kinetics of the formation of NO during
X
methane-air combustion by Exxon Research and Engineering and the inves-
tigation of chemical reactions in the conversion of fuel nitrogen to
NO by Rocketdyne. The Jet Propulsion Laboratory has reported on the
IV-443
-------
role of flame interactions in pollutant formation. United Technology
Research Center has discussed the effect of the interactions between
fluid dynamics and chemistry in pollutant formation as well as two
dimensional combustor modeling. Aerotherm has reviewed their work on
prediction of the kinetics of premixed laminar flat flames and Stanford
Research Institute has reported on the estimation of rate constants. MIT
has described their research on the fate of fuel nitrogen during the pyrolysis
and oxidation of coal and on the formation of soot and polycyclic aromatic
hydrocarbons during combustion. The University of Arizona has reported on
investigations of the effect of fuel sulfur on NO emissions.
In the area of fuels R&D the Institute of Gas Technology has
reported on burner design criteria to control pollutant emissions from
natural gas flames, while Ultrasystems has discussed their investigations
to optimize burner design to reduce NO emissions from pulverized coal
and residual oil flames, along with their work to control emissions
from packaged boiler systems. Rocketdyne has reviewed their work on
an integrated low emission residential furnace system. Aerotherm has
discussed investigations they are initiating to study a pilot scale
combustion modification technique applicable to industrial and utility
boilers and also catalytic combustion concepts for residential and
industrial applications. EPA's in-house study on the assessment of the
combustion and emission characteristics of alcohols and other alternate
fuels has been summarized.
IV-444
-------
The process R&D work which involves studies with commercial or
prototype combustion systems to develop cost and design information for
the application of NO control technology to classical combustion systems
A
and which form the basis for future demonstrations were reported yester-
day. Combustion Engineering reported on their investigations of the
use of overfire air as a means of controlling NO in tangential coal-
fired utility boilers. TVA described their investigations of staged
combustion as a technique for controlling NO formation in wall coal-fired
utility boilers. Ultrasystems reviewed their study addressing pollutant
formation and furnace design in low Btu gas fired boilers. Battelle-
Columbus has discussed the effectiveness of fuel additives as a means
of reducing pollutant emissions.
The field testing and surveys are studies designed to determine
what can be achieved currently to control NO emissions with state-of-the-art
control technology. Among the papers in this area, Exxon has presented
their findings on the effect of combustion modifications on pollutant
emissions and on the performance of utility boilers. KVB, Inc. has reported
on the effect of combustion modification on pollutant emissions from
industrial boilers and on the use of Western coals in small and inter-
mediate size boilers. Aerospace Corporation has reviewed their analysis
of test data for utility boilers burning gas, oil and coal. EPA's
in-house assessment of the emission characteristics of small gas turbine
engines has been discussed. Battelle-Columbus has told us of the emissions
from small commercial stoker-fired coal-burning boilers;
IV-445
-------
and IGT has presented their survey findings on industrial process
heating combustion equipment data and emissions control.
The goal of all of these studies (even indirectly of the funda-
mental research is ultimately the development and assessment of economical
and efficient combustion modification techniques which will find practical
application for the control of NO and other combustion-generated
X
pollutants. Our real purpose is to effectively solve the problems of
pollution of the environment. To accomplish this we need data and in-
formation which will guide us to the development and application of
practical and effective control methods. Many of the results reported
here are quite informative and show that good progress is being made in
some areas toward abating NO and other pollutants without adversely
X
affecting the performance of the energy conversion systems in other
critical respects. On the other hand a number of the R&D efforts,
while obtaining answers to some of the questions and providing data for
some of the unknowns, are opening up new questions which will require
answers. In fact, we see that some of the data, at least on first
scrutiny, appear to be in conflict or saying different things. There
are many areas, I feel sure, where the information presented here will
indicate directions which will be carefully considered by us in planning
future work. I feel we are making good progress, both in the basic
research and modeling of the combusiton processes and pollutant reactions
and in the development and assessment of practical control techniques.
There has been great evidence of the interest on the part of the various
TV-446
-------
investigators and the participants as shown by the large number of ques-
tions and the enthusiasm of the follow-up discussions. I really believe
the main purpose of our meeting which was information exchange has to a
large degree been achieved. We must conclude however that much work
remains to be done and we need to move ahead vigorously with our R&D
activities in order to solve the many stationary combustion source
pollution problems which still remain.
We want to express our appreciation to the authors and especially
to the speakers for their efforts in preparing and presenting the highly
informative papers. Also, we want to thank the featured speakers and
participants in the panel discussions, including Adel Sarofin, Tom Tyson,
Stan Cuffe, Tom Helms, Bob Collon, T. T. Kason and Bob Rosenberg, for
their thought-provoking presentations. For all of the attendees, we
are particularly gratified that you were able to take the time to meet
with us and that you were responsive in participating in the discussion
periods. That is what really makes a meeting of this type successful.
We also would like to commend the staff of A. D. Little, particularly
Marjorie Maws and Anita Lord, and Mr. Robert Hall of the CRB staff who
was project officer and vice-chairman of the symposium, and all of the
others who have been instrumental in planning and arranging the details
of the program and facilities for the meeting. Special mention should
be made of the outstanding facilities and services provided by the
Fairmont Colony Square.
IV-447
-------
It is planned that the papers presented here and the related discus-
sions will be compiled and issued as proceedings of the symposium. This
EPA report, which will include a list of attendees, will be sent to
each of you. However, because of the effort involved in preparing the
documentation, you may not receive it until late November or December.
Additional copies will be available through the NTIS.
This meeting has provided an additional opportunity for participa-
tion by industry and other Government agencies in our program activities.
We shall welcome any further comments or recommendations you may have
regarding the technical activities as well as future meetings. With
regard to available technical information, our studies generate a large
number of reports and related documents. A listing of the Industrial
Environmental Research Laboratory reports is issued in a Report Abstracts
document which is published monthly and may be obtained by contacting
W. W. Whelan of IERL-RTP. Although future meetings have not yet been
planned, it is anticipated that we will continue our practice of holding
symposia as a means of exchanging technical information at appropriate
times in the future. In order to help us improve our meetings and make
them more responsive to all our needs, I would like to remind you of
the Meeting Rating Form which was placed in your program schedule. Would
you please take the few minutes needed, perhaps on your trip home, to
fill out responses to the various questions and send the form to us.
In this way perhaps we can uncover suggestions which will improve the
quality of future meetings.
IV-448
-------
Again, let me thank each of you for coming here and taking part in
this meeting. I hope it has proved for each of you to be a worthwhile
experience. I wish you a safe and pleasant journey home and on that
note we shall consider the meeting adjourned.
IV-449
-------
IV-450
-------
SPEAKERS LIST
(NOTE: To facilitate their identification, speakers are listed alphabetically
together with the name of the organization they represent. The complete address
of each organization represented at the conference appears at the end of the list
of attendees.)
LIST OF SPEAKERS
Matne
Axworthy, Dr. Arthur E.
Mttner, James D.
Bowen, Dr. Joshua A.
Bowman, Dr. Craig T.
trown, Richard A.
Eurchard, Dr. John 1C.
Cato, Glenn A.
Collom, Jr., Robert H.
Combs, L. Paul
Crawford, Allen R.
Cuffe, Stanley T.
Dykeraa, Owen W.
England, Dr. Christopher
Erigleman, Dr. Victor S.
Giammar, Robert P.
Hsll, Robert E.
Heap, Dr. Michael P.
Helms, G. Thomas
Hollinden, Dr. Gerald A.
Kason, T.T.
Kendall, Dr. Robert M
Keisselring, Dr. John P.
Ker.els, Peter
Lachapelle, David G.
Lanier, W. Steven
Mclonald, Henry
Maloney, Dr. Kenneth L.
Manny, Erwin H.
Martin, G. Blair
Muzio, Dr. Lawrence J.
Poh.l, John H.
Poszon, H. Wallace
Princiotta, Frank
Rosenberg, Dr. Robert B.
Sarofim, Dr. Adel F.
Selk.er, Ambrose P.
Shav, Dr. Robert
Shoffstall, Dr. Donald R.
Tyson, Dr. Thomas J.
Wasser, John H.
Wends, Dr. Jost O.L.
Representing
Rockwell International, Rocketdyne Division
Massachusetts Institute of Technology
EPA, IERL, Combustion Research Branch
United Technology Research Center
Acurex, Aerotherm Division
EPA, IERL
KVB, Inc.
State of Georgia, Department of Natural Resources
Rockwell International, Rocketdyne Division
Exxon Research and Engineering
EPA, Office of Air Quality Planning and Standards
The Aerospace Corporation
Jet Propulsion Laboratory
Exxon Research and Engineering
Battelle-Columbus Laboratories
EPA, IERL, Combustion Research Branch
Ultrasystems
EPA, Region IV, Air and Hazardous Materials Division|
Tennessee Valley Authority
City of Chicago, Department of Environmental Control|
Acurex, Aerotherm Division
Acurex, Aerotherm Division
Institute of Gas Technology
EPA, IERL, Combustion Research Branch
EPA, IERL, Combustion Research Branch
United Technology Research Center
KVB, Inc.
Exxon Research and Engineering
EPA, IERL, Combustion Research Branch
KVB, Inc.
Massachusetts Institute of Technology
City of Chicago, Department of Environmental Control|
EPA, Energy Processes Division
Institute of Gas Technology
Massachusetts Institute of Technology
Combustion Engineering
Stanford Research Institute
Institute of Gas Technology
Ultrasystems
EPA, IERL, Combustion Research Branch
University of Arizona
A-l
-------
PARTICIPANTS LIST
(NOTE: To facilitate their identification, participants are listed alphabetically
together with the name of the organization they represent. The complete address
of each organization represented at the conference appears at the end of the list
of attendees.)
LIST OF PARTICIPANTS
Name
Alvey, Courtney D.
Anderson, Dr. Larry W.
Axtman, William H.
Bagwell, Fred A.
Baker, Burke
Ban, Stephen D.
Barrett, Richard E.
Barsln, Joseph
Bartok, William
Batra, Sushil K.
Bauman, Robert D.
Beals, Rixford A.
Beatty, James D.
Bennett, Dr. Robert
Blandford, Jr., J.B.
Blythe, R. Allen
Buechler, Lester
Bonne, Ulrich
Booth, Michael R.
Bowman, Barry R.
Bueters, K.A.
Carpenter, Ronald C.
Cernansfcy, Dr. Nicholas P.
Christiano, John P.
Chu, Richard R.
Clark, Norman D.
Cleverdon, R.F.
Cotton, Ernest
Creekmore, Andrew T.
Daughtridge, Jimmy T.
Degler, Gerald H.
Demetri, E.P.
DeWerth, D.W.
Dingo, T.T.
)onaldson, Thomas M.
Dowling, Daniel J.
)owney, Thomas A.
Dyer, T. Michael
Dygert, J.C.
Representing
Baltimore Gas & Electric
Acurex, Aerotherm Division
American Boiler Manufacturers Association
South California Edison
Shell Development Company
Battelle-Columbus Laboratories
Battelle-Columbus Laboratories
Babcock & Wilcox
Exxon Research & Engineering
New England Electric Systems
EPA, Office of Air Quality, Planning & Standards
NOFI
Procter & Gamble
Apollo Chemical
Englehard Industries
International Boiler Works
Systems Research Labs
Honeywell
Ontario Hydro
Lawrence Livermore Laboratories
Combustion Engineering
Armstrong Cork
Drexel University
EPA, Office of Air Quality, Planning & Standards
EBASCO
C-E Air Preheater
Chevron Research Company
American Petroleum Institute
EPA, Control Programs Development Division
Pratt & Whitney Aircraft
Systems Research Labs
Northern Research and Engineering Corporation
American Gas Association Labs
General Motors
EPA, Office of Air Quality, Planning & Standards
Union Carbide
Gamlen Chemical Company
Sandia Laboratories
Shell Development Company
A-2
-------
LIST OF PARTICIPANTS (CONT'D)
Name
Dzuna, Eugene R.
Erskine, George
Feng, C.L.
Fennelly, Paul F.
Fletcher, James
Fletcher, Roy J.
Freelain, Kenneth
Frisch, Dr. N.W.
Fuhrman, Jr., Theodore
Gibbs, Thomas
Goetz, Gary
Soodley, Allan R.
Graham, David J.
Greene, Jack H.
Grimshaw, Vincent C.
Gr o s sman, Ralph
Eangebrauck, Robert P.
Heck, Ronald
Hensel, Thomas E.
Halden, Edward A.
Honea, Dr. Franklin I.
Howard, Jack B.
Hudson, Jr., James L.
Jsickson, Dr. A.W.
Jepson, Dr. A.F.
Karas, Dennis T.
Kemmerer, Jeffrey
Khan, M. Ali
KhDO, Dr. S.W.
Kloecker, J.F.
Kykendal, William
Lahre, Thomas
Large, Dr. Howard
Lavoie, Raymond C.
Lee, James E.
Lenney, Ronald J.
Levy, Arthur
Lewis, F. Michael
Lii. Dr. C.C.
Lin, Donald J.L.
Locklin, David W.
Lord, Harry C.
Loweth, Carl
Marshall, David
Marshall, John H.
Representing
Gulf Research & Development Company
Mitre Corporation
Selas Corporation of America
GCA/Technology Division
Industrial Combustion
Peabody Engineering Corporation
Federal Energy Administration
Research-Cottrell
Erie City Energy Division
EPA, Region IV
Combustion Engineering
California Air Resources Board
EPA, Office of Research and Development
EPA, Administrative Office
Process Combustion
Ralph Grossman, Ltd.
EPA, Energy Assessment and Control Division
Englehard Industries
Turbo Power and Marine Systems
General Foods Corporation
Midwest Research Institute
Massachusetts Institute of Technology
Tampa Electric Company
Ontario Hydro
Environmental Measurements, Inc.
East Chicago Air Quality Control
Fuller Company
East Chicago Air Quality Control
Canadian Gas Research Institute
Erie City Energy Division
EPA, Process Measurement Branch
EPA, Office of Air Quality, Planning & Standards
Babcock & Wilcox
Rohm & Haas Company
Facilities Engineering Command (U.S. Navy)
Ronald J. Lenney Associates
Battelle-Columbus Laboratories
Stanford Research Institute
EPA, Combustion Research Branch
Forney Engineering Company
Battelle-Columbus Laboratories
Environmental Data Corporation
The Trane Company
Babcock & Wilcox
Combustion Engineering
A-3
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LIST OF PARTICIPANTS (CONT'D)
Name
Marton, Miklos B.
Mayfield, D. Randell
Meier, John G.
Moore, Douglas S.
Moore, Edward E.
Morton, William J.
Moscowitz, Charles
Mosier, Stanley A.
Newton, Charles L.
Nurick, W.H.
Pantzer, Karl
Pershing, David W.
Pertel, Dr. Richard
Renner, Ted
Riley, Joseph
Robert, J.
Roberts, Dr. George
Robertson, J.F.
Roffe, Gerald
Rosen, Meyer
Ross, Marvin
Rulseh, Roy
Sadowski, R.S.
Samples, J.R.
Scott, Donald R.
Sheffield, E.W.
Slack, A.V,
Smith, Lowell L.
Spadaccini, L.J.
Sterman, Sam
Sullivan, Robert E.
Swearingen, W.E.
Takacs, Dr. L.
Taylor, Barry R.
Utterback, Paul M.
Van Grouw, Sam J.
Vatsky, Joel
Vershaw, Jim
Watson, Raymond A.
Webb, R.
Weiland, J.H.
Weinberger, Dr. Lawrence
White, David J.
White, James H.
White, Phil
Representing
IBM
EPA, Region IV
International Harvester, Solar Division
Chevron Research Company
Eclipse, Inc.
E. Keeler Company
Monsanto Research Corporation
Pratt & Whitney
Colt Industries
Rockwell International, Rocketdyne Division
Babcock & Wilcox
University of Arizona
Institute of Gas Technology
Fuel Merchants Association of New Jersey
EPA, Region IV
Canadian Department of Environment
Englehard Industries
Crystal Petroleum Company
General Applied Science Laboratories
Union Carbide
Lawrence Livermore Laboratory
Cleaver-Brooks
Riley Stoker Corporation
Union Carbide
Columbia Gas System Service Corporation
TRW
SAS Corporation
KVB, Inc.
United Technology Research Center
Union Carbide
General Motors
Koppers Company
General Motors
Massachusetts Institute of Technology
Babcock & Wilcox
KVB, Inc.
Foster-Wheeler Energy Corporation
The Trane Company
Florida Power & Light Company
The Trane Company
Texaco, Inc.
Mitre Corporation
International Harvester, Solar Division
Coen Company
Ventura Company
_
A-4
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Name
Wiedersum, George C.
Wilhelm, Ronald
Wilson, Jr., P..P.
Winters, Harry K.
Wittig, Dr. Sigmar L.K.
Woolfolk, Dr. Robert
Wright, Richard
Young, Dexter E.
Ziarkowski, Stanley
Zielke, Robert L.
Zirkel, Eric C.
LIST OF PARTICIPANTS (CONT'D)
Representing
Philadelphia Electric Company
Aqua-Chem, Inc.
Arthur D. Little, Inc.
Ray Burner Company
Purdue University
Stanford Research Institute
Industrial Combustion
EPA, Control Programs Development Division
Garnien Chemical Company
Tennessee Valley Authority
Armstrong Cork
A-5
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LIST OF ORGANIZATIONS REPRESENTED
Name (Represented By)
Acurex Corporation, Aerotherm Division
(Mr. Anderson)
American Boiler Manufacturers Association
(Mr. Axtman)
American Gas Association Labs
(Mr. De Werth)
American Petroleum Institute
(Mr. Cotton)
Apollo Chemical
(Dr. Bennett)
Aqua-Chem, Inc.
(Mr. Wilhelm)
Armstrong Cork Company
(Mr. Carpenter, Mr. Zirkel)
Babcock & Wilcox
(Mr. Bartin, Mr. Lange, Mr. Moore)
(Mr. Utterback, Mr. Pantzer,
Mr. Marshall)
Baltimore Gas and Electric Company
(Mr. Alvey)
Battelle-Columbus Labs
(Mr. Ban, Mr. Barrett,
Mr. Levy, Mr. Locklin)
C-E Air Preheater
(Mr. Clark)
California Air Resources Board
(Mr. Goodley)
Canadian Department of Environment
(Mr. Robert)
Canadian Gas Research Institute
(Dr. Khoo)
Chevron Research Company
(Mr. Cleverdon, Mr. D. Moore)
Address
485 Clyde Avenue
Mountain View, California 94042
1500 Wilson Boulevard, Suite 317
Arlington, Virginia 22209
8501 East Pleasant Valley Road
Cleveland, Ohio 44131
1801 K Street, N.W.
Washington, D.C. 20006
35 South Jefferson Road
Whippany, New Jersey 07981
P.O. Box 421
Milwaukee, Wisconsin 53201
Liberty & Charlotte Streets
Lancaster, Pennsylvania 17604
20 South Van Buren Avenue
Barberton, Ohio 44203
P.O. Box 2423
North Canton, Ohio 44720
2012 Gas and Electric Building
Baltimore, Maryland 21203
505 King Avenue
Columbus, Ohio 43201
Andover Road
Wellsville, New York 14895
1709 llth Street
Sacramento, California 95814
351 St. Joseph Boulevard
Houll, Quebec, Canada
55 Scarsdale Road, Don Mills
Ontario, M3B2R3, Canada
P.O. Box 1627
Richmond, California 94802
A-6
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LIST OF ORGANIZATIONS (CONT'D)
Name (Represented By)
Cleaver-Brooks
(Mr. Rulseh)
Coen Company
(Mr. J.H. White)
Colt Industries
(Mr. Newton)
Columbia Gas System Service Corporation
(Mr. Scott)
Combustion Engineering
(Mr. Bueters, Mr. Goetz, Mr. Marshall)
Crystal Petroleum Company
(Mr. Robertson)
Drexel University
(Dr. Cernansky)
EBASCO
(Mr. Chu)
East Chicago Air Quality Control
(Mr. Karas, Mr. Khan)
Eclipse, Inc.
(Mr. E. Moore)
Englehard Industries
(Mr. Blandford, Dr. Heck, Dr. Roberts)
Environmental Data Corporation
(Mr. Lord)
Environmental Measurements, Inc.
(Dr. Jepsen)
Environmental Protection Agency
EPA - Administrative Office
(Mr. Greene)
Address
3707 North Richards Street
Milwaukee, Wisconsin 53201
1510 Rollins Road
Burlingame, California 9401C
701 Lawton Avenue
Beloit, Wisconsin 53511
1600 Dublin Road
Columbus, Ohio 43215
1000 Prospect Hill Road
Windsor, Connecticut 06095
P.O. Box 4180
Corpus Christi, Texas 78408
Philadelphia
Pennsylvania 19104
145 Technology Park
Norcross, Georgia 30071
900 East Chicago Avenue
East Chicago, Indiana 45312
1100 Buchanan
Rockford, Illinois 61101
Middlesex Turnpike, Wood AvenJ
Edison, New Jersey 08876
608 Fig Avenue
Monrovia, California 91016
2 Lincoln Court
Annapolis, Maryland 21401
Research Triangle Park
North Carolina 27711
A-7
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LIST OF ORGANIZATIONS (CONT'D)
flame (Represented By)
EPA - Combustion Research Branch
(Dr. Bowen, Mr. Hall, Mr. Lachapelle,
Mr. Lanier, Dr. Lii, Mr. Martin, Mr. Wasser)
SPA - Control Programs Development Division
(Mr. Creekmore, Mr. Young)
EPA - Energy Assessment & Control Division
(Mr. Hangebrauck)
EPA - Office of Air Quality, Planning,
and Standards
(Mr. Bauman, Mr. Christiano,
Mr. Donaldson, Mr. Lahre)
EPA - Office of Research and Development
(Mr. Graham)
EPA - Process Measurement Branch
(Mr. Kuykendal)
EPA - Region IV
(Mr. Biggs, Mr. Mayfield, Mr. Riley)
Erie City Energy Division
(Mr. Fuhrman, Mr. Kloecher)
Exxon Research & Engineering Company
(Mr. Bartok)
Federal Energy Administration
(Mr. Freelain)
Florida Power & Light Company
(Mr. Watson)
Forney Engineering Company
(Mr. Lin)
Foster Wheeler Energy Corporation
(Mr. Vatsky)
Fuel Merchants Association of New Jersey
(Mr. Renner)
Address
Research Triangle Park
North Carolina 27711
Research Triangle Park
North Carolina 27711
Research Triangle Park
North Carolina 27711
Research Triangle Park
North Carolina 27711
Washington, D.C. 20460
Research Triangle Park
North Carolina 27711
1421 Peachtree Street, N.E.
Atlanta, Georgia 30309
1422 East Avenue
Erie, Pennsylvania 16502
P.O. Box 8
Linden, New Jersey 07036
1200 Pennsylvania Avenue, N.W.
Washington, D.C. 20461
P.O. Box 013100
Miami, Florida 33101
P.O. Box 189
Addison, Texas 75001
10 South Orange Avenue
Livingston, New Jersey 07039
66 Morris Avenue
Springfield, New Jersey 07081
A-8
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LIST OF ORGANIZATIONS (CONT'D)
Name (Represented By)
Fvller Company
(Mr. K.fi'juerer)
GC A/Technology Division
(Dr. Fennelly)
Gainlen Chemical Company
(Nr. Downey, Mr. Ziarkowski)
Ger.eral Applied Science Laboratories
(Mr. Roffe)
Genera? Foods - Technical Center
(Mr. Holden)
General Motors Corporation
(Mr. Sullivan)
(Mr. Dingo, Mr. Takacs)
Gulf Research and Development Company
(Mr. Dzuna)
, Inc.
(Mr . Bonne)
IBM
(Mr. Marton)
Industrial Combustion
(Mr. Wright, Mr. Fletcher)
Instiuute ot G:?s Technology
(Dr. Pertel)
International Boiler Works
(Mr. Ely the)
International Harvester, Solar Division
(Mr. Meier, Mr. D.G. White)
124 Bridge Street
Catasauqua, Pennsylvania 18032
Burlington Road
Bedford, Massachusetts 01730
299 Market Street
Saddle Brook, New Jersey 07662
Merrick & Stewart Avenues
Westbury, New York 11790
250 North Street
White Plains, New York 10625
5735 West 25th Street
Indianapolis, Indiana 46224
Technical Center
Warren, Michigan 48090
P.O. Box 2038
Pittsburgh, Pennsylvania 15230
Bloomington
Minnesota 55420
1000 Westchester Avenue
White Plains, New York 10604
4465 North Oakland
Milwaukee, Wisconsin 53211
3424 South State Street
Chicago, Illinois 60616
P.O. Box 498
East Stroudsburg, Pennsylvania 18301
2200 Pacific Highway
San Diego, California 92119
A-9
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LIST OF ORGANIZATIONS (CONT'D)
I Name (Represented By)
Engineering, Inc.
(Mr. L. Smith, Mr. Van Grouw)
|E. Keeler Company
(Mr. Morton)
|Koppers Company, Inc.
(Mr . Swearingen)
| Ronald J. Lenney Associates
(Mr . Lenney)
(Arthur D. Little, Inc.
(Mr. R.D. Wilson)
I Lawrence Livermore Laboratories
(Mr. Bowman, Mr. Ross)
(Massachusetts Institute of Technology
(Mr. Howard, Mr. Taylor)
[Midwest Research Institute
(Dr . Honea)
[Mitre Corporation
(Dr. Weinberger, Mr. Erskine)
Monsanto Research Corporation
(Mr. Moscowitz)
NOFI
(Mr. Seals)
Naval Facilities Engineering Command,
Southern Division
(Mr. J. Lee)
New England Electric Systems
(Mr. Batra)
Northern Research & Engineering Corporation
(Mr. Demetri)
Address
6624 Hornwood Drive
Houston, Texas 77036
Williamsport
Pennsylvania 17701
Koppers Building
Pittsburgh, Pennsylvania 15219
2001 Palmer Avenue
Larchmont, New York 10538
Acorn Park
Cambridge, Massachusetts 02140
P.O. Box 808
Livermore, California 94550
Massachusetts Avenue
Cambridge, Massachusetts 02139
425 Volker Boulevard
Kansas City, Missouri 64110
Westgate Research Park
1820 Dolly Madison Boulevard
McLean, Virginia 22101
Station B. Box 8
Dayton, Ohio 45407
New York, New York
2144 Melbourne Street
P.O. Box 10068
Charleston, South Carolina 29411
20 Turnpike Road
Weston, Massachusetts 01581
219 Vassar Street
Cambridge, Massachusetts 02139
A-10
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LIST OF ORGANIZATIONS (CONT'D)
Name (Represented By)
Ontario Hydro Corporation
(Mr. Booth, Dr. Jackson)
Peabody Engineering Corporation
(Mr. R. Fletcher)
Philadelphia Electric Company
(Mr. Wiedersom)
Pratt & Whitney Aircraft
(Mr. Daughtridge, Mr. Mosier)
Process Combustion Corporation
(Mr. Grimshaw)
Procter & Gamble Company
(Mr. Beatty)
Purdue University
(Mr. Wittig)
Ralph Grossman, Ltd.
(Mr. Grossman)
Ray Burner Company
(Mr. Winters)
Research-Cottrell, Inc.
(Dr. Frisch)
Riley Stoker Corporation
(Mr. Saclowski)
Rockwell International Corporation,
Roc-tetdyne Division
(Mr. Nurick)
Rohm & Haas Company
(Mr. Lavoie)
SAS Corporation
(Ar. Slack)
Address
620 Union Avenue
Toronto, Ontario, Canada M561X6
835 Hope Street
Stamford, Connecticut 06907
2301 Market Street, S10-1
Philadelphia, Pennsylvania 19101
P.O. Box 2691
West Palm Beach, Florida 33402
1675 Washington Road
Pittsburgh, Pennsylvania 15228
610 South Center Hill Road
Cincinnati, Ohio 45224
West Lafayette
Indiana 47907
P.O. Box 70, Town of Mt. Royal
Montreal, Canada H3P 3B8
1301 San Jose Avenue
San Francisco, California 94112
P.O. Box 750
Boundbrook, New Jersey 08805
9 Neponset Street
Worcester, Massachusetts 01613
6633 Canoga Avenue
Canoga Park, California 91304
P.O. Box 584
Bristol, Pennsylvania 19007
RFD #1
Sheffield, Alabama 35660
A-ll
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LIST OF ORGANIZATIONS (CONT'D)
Name (Represented By)
Sandia Laboratories
(Mr. Dyer)
Selas Corporation of America
(Mr. Feng)
Shell Development Company
(Mr. Dygert, Mr. Baker)
South California Edison
(Mr. Bagwell)
Stanford Research Institute
(Dr. Woolfolk, Mr. Lewis)
Systems Research Labs
(Mr. Buechler, Mr. Degler)
TRW, Inc.
(Mr. Sheffield)
Tampa Electric Company
(Mr. Hudson)
Tennessee Valley Authority
(Mr. Zielke)
Texaco, Inc.
(Mr. Weiland)
The Trane Company
(Mr. Loweth, Mr. Vershaw, Mr. Webb)
Turbo Power and Marine Systems
(Mr. Hensel)
Union Carbide Corporation
(Mr. Rosen, Mr. Sterman)
(Mr. Dowling)
Address
Livermore
California 94550
Dresher
Pennsylvania 19025
P.O. Box 481
Houston, Texas 77001
P.O. Box 800
Rosemead, California 91770
1611 North Kent Street
Arlington, Virginia 22209
2800 Indian Ripple Road
Dayton, Ohio 45440
1 Space Park - R4/2020
Redondo Beach, California 90278
P.O. Box 111
Tampa, Florida 33601
524 Power Building
Chattanooga, Tennessee 37401
P.O. Box 509
Beacon, New York 12508
3600 Pammel Creek Road
La Crosse, Wisconsin 54601
1690 New Britain Avenue
Farmington, Connecticut 06032
Tarrytown Technical Center
Tarrytown, New York 10591
Box 180
Sistersville, West Virginia 26175
A-12
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LIST OF ORGANIZATIONS (CONT'D)
Hame (Represented By)
Union Carbide Corporation
(M:r. Samples)
United Technologies Research Center
(Mr. Spadacclni)
University of Arizona
(Mr. Pershing)
Ventura County A.P.C.D.
(Mr. P. White)
Address
Box 4361
South Charleston, West Virginia 25353
400 Main Street
East Hartford, Connecticut 06040
Tucson
Arizona 85721
740 East Main Street
Ventura, California 93001
A-13
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TECHNICAL REPORT DATA
(Pirate rrad InOsuciions On the rei'crtc before completing)
1. REPORT NO.
EPA-600/2-76-152c
2.
3. RECIPIENT'S ACCESSION*NO.
4. T.TLE AND SUBTITLE proceedings o{ the stationary Source
Combustion Symposium; Volume HI—Field Testing
and Surveys
5. REPORT DATE
June 1976
6. PERFORMING ORGANIZATION CODE
7. AUTMOR(S)
Miscellaneous
B. PERFORMING ORGANIZATION REPORT NO
9. PERFORMING OR9ANIZATION NAME AND ADDRESS
NA
10. PROGRAM ELEMENT NO.
1AB014; ROAP 21BCC
11: CONTRACT/GRANT NO.
NA (In-house)
2. SPONSORING AGENCY NAME AND ADDRESS
EPA, Office of Research and Development
Industrial Environmental Research Laboratory
Research Triangle Park, NC 27711
13. TYPE OF REPORT AND PERIOD COVERED
Proceedings: 9/24-26/75
14. SPONSORING AGENCY CODE
EPA-ORD
5.SUPPLEMENTARYNOTEsSymposium Chairman J.S. Bowen, Vice-Chair man R.E. Hall,
Mail Drop 65, Ext. 2470/2477.
s. ABSTRACT
proceedings document the 37 presentations made during the Stationary
Source Combustion Symposium held in Atlanta, Ga. , September 24-26, 1975. Spon-
sored by the Combustion Research Branch of EPA's Industrial Environmental Resea-
rch Laboratory- -RTP, the symposium dealt with subjects related both to developing
improved combustion technology for the reduction of air pollutant emissions from
stationary sources , and to improving equipment efficiency. The symposium was
divided into four parts and the proceedings were issued in three volumes: Volume I —
Fundamental Research, Volume U--Fuels and Process Research and Development,
and Volume m--Field Testing and Surveys. The symposium was intended to provide
contractor, industrial, and Government representatives with the latest information
on EPA in-house and contract combustion research projects related to pollution
control, with emphasis on reducing nitrogen oxides.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTlFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Air Pollution, Combustion, Field Tests
ombustion Control, Coal, Oils
Natural Gas, Nitrogen Oxides, Carbon
arbon Monoxide, Hydrocarbons, Boilers
Pulverized Fuels, Fossil Fuels, Utilities
Gas Turbines, Efficiency
Air Pollution Control
Stationary Sources
Combustion Modification
Unburned Hydrocarbons
Fundamental Research
Fuel Nitrogen
Burner Tests
13B 21B 14B
2 ID 11H
07B
07C 13A
13G 14A
8. DISTRIBUTION STATEMENT
Unlimited
19. SECURITY CLASS (ThisReport}
Unclassified
21. NO. OF PAGES
474
2O. SECURITY CLASS (Thispage)
Unclassified
22. PRICE
EPA Form 222O-\ (9-73)
A-14
•U.S. GOVERNMENT PRINTING OFFKS: 1976-641-317/SS12 Region He. 4
-------
I HP 6QO/2 ;;?A
|76-152c Industrial ICnv Rr.s Lab
AUTHOR
Proceedings of the stationary
T'TLEsourr.e combust, ior. symDosium
_V . 3: b'icld testing :•. surveys
OATE DiJE
BORROWERS NAME
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DATE DUE i
BORHOWtH'S NAME
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DATE DUE
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