i—1 UJ
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United States
Environmental Protection
Agency
Industrial Environmental Research
Laboratory
Research Triangle Park NC 27711
EPA-600/7-79-240
November 1979
Preservation of Reactor
Test Unit and
Desulfurization of
Gob Pile Samples
Interagency
Energy/Environment
R&D Program Report
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
8. "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the INTERAGENCY ENERGY-ENVIRONMENT
RESEARCH AND DEVELOPMENT series. Reports in this series result from the
effort funded under the 17-agency Federal Energy/Environment Research and
Development Program. These studies relate to EPA's mission to protect the public
health and welfare from adverse effects of pollutants associated with energy sys-
tems. The goal of the Program is to assure the rapid development of domestic
energy supplies in an environmentally-compatible manner by providing the nec-
essary environmental data and control technology. Investigations include analy-
ses of the transport of energy-related pollutants and their health and ecological
effects; assessments of, and development of, control technologies for energy
systems; and integrated assessments of a wide range of energy-related environ-
mental issues.
EPA REVIEW NOTICE
This report has been reviewed by the participating Federal Agencies, and approved
for publication. Approval does not signify that the contents necessarily reflect
the views and policies of the Government, nor does mention of trade names or
commercial products constitute endorsement or recommendation for use.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/7-79-240
November 1979
Preservation of Reactor Test Unit
and Desulfurization of Gob Pile Samples
by
W.D. Hart, LC. McClanathan, R.A. Meyers,
and D.M. Wever
TRW Defense and Space Systems Group
One Space Park
Redondo Beach, California 90278
Contract No. 68-02-1880
Program Element No. INE825
I
EPA Project Officer: Lewis D. Tamny
Industrial Environmental Research Laboratory
Office of Environmental Engineering and Technology
Research Triangle Park, NC 27711
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washington, DC 20460
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ABSTRACT
The development of the Meyers Process for ferric sulfate leaching of
pyritic sulfur from coal has been sponsored through construction and opera-
tion of an eight ton per day test plant, termed the Reactor Test Unit
(RTU). Operation of the test plant 1n 1977 and 1978 showed that the unit
could be run continuously 1n three-shift operation to reduce the sulfur
content of the feed coal to meet the 1.2 pound Standard for New Stationary
Sources. Corrosion problems were encountered 1n the stainless steel main
reactor which required modifications prior to any further testing. This
present program provided a complete corrosion assessment, specification of
a hew main reactor of titanium, specification of a tall-end elemental
sulfur extraction unit and maintenance of the RTU.
A modification of the Meyers Process, Involving a preliminary float
and sink operation In the ferric sulfate leach solution, followed by Meyers
processing of the sink (high pyrlte) fraction was Investigated at bench-
scale. Experimental verification and applicability assessment of this
new approach was performed on both waste and Eastern Interior Basin run-of-
mine coal.
111
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CONTENTS
Abstract . . 11 i
Figures vi
Tables . ; x1
1.0 Introduction 1
2.0 Conclusions 6
3.0 Recommendations 7
4.0 Reactor Test Unit Inspection and Preservation 8
4.1 Introduction 8
4.2 Background .... ...... 8
4.3 Routine Maintenance During Standby 11
4.4 RTU Inspection and Inspection Results 16
4.4.1 Coal Feed System 23
4.4.2 Leach Solution and Waste Liquid Storage System. 24
4.4.3 Leach Solution Feed System 24
4.4.4 Coal Slurry Preparation System 27
4.4.5 Primary Reactor System 30
4.4.6 Gas Vent System 31
4.4.7 Secondary Reactor System 32
4.4.8 Filtration and Leach Solution Recovery System . 33
4.4.9 Gasket Sealing Surfaces ... 35
4.4.10 Equipment Spare Parts 38
5.0 Bench-Scale Extractions (Task 2A) T24
5.1 TVA Coal Studies (Task 2A1) 124
5.1.1 Float-Sink (Organic Liquid) (Task 2Ala) .... 124
5.1.2 Float-Sink (Leach Solution) (Task 2Alb) .... 126
5.1.3 Meyers Process on ROM Coal (Sink) (Task 2Alc) . 126
5.1.4 Float-Sink 3/8" x 0 Coal (Task 2Ald) 126
1v
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CONTENTS (Continued)
5.2 Gob Pile Coals (Task 2A2) 134
5.2.1 Float-Sink - Gob Coals (Task 2A2) 134
5.2.2 Float-Sink Analysis (Task 2A2) 136
5.2.3 Meyers Processing (Task 2A2) 139
6.0 Specifications and Estimates for R-l Reactor Replacement. . . 143
7.0 RTU Acetone Extraction Unit 148
7.1 TEU Conceptual Design 148
7.1.1 Process Description 149
7.1.2 TEU Design Basis 158
7.2 TEU Cost Estimate 158
8.0 Application Studies 166
8.1 Applicability of Gravlchem Process for U.S. Coals. ... 166
8.2 Applicability of the Gravlchem Process for Waste Coal
Recovery 168
8.2.1 Coal 011 or Coal Water Mixtures for Boiler
Retrofit 168
8.2.2 Gravlfloat Process for Recovery of High Grade
Fine Coal from Slurry Ponds 170
8.2.3 Waste Coal Recovery from TVA Mine 173
9.0 References 175
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FIGURES
Number Page
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Federal Energy Technology Test Facility Sponsored by
U.S. Environmental Protection Agency at TRW's San
Juan Caplstrano Test Site
Gravlchem Process
RTU Schematic
RTU Control Console
View RTU - West Side
Coal Bin TUter ,
Equipment on Level 4 of RTU
Coal Feed Tanks T-l and T-6 and Weigh Belt Feeder A-3. . . ,
Slurry Mix Tank T-2 ,
Slurry Mix Tank T-2 and Primary Reactor R-l ,
Belt Filter ,
Filtrate Collection Equipment ,
Redrculatlon Pumps for Reactor R-l
Leach Solution Storage Tanks and Pumps ,
Rubber Boot Between Coal Storage Tank T-l and Live
Bottom Feeder A-2
Rotary Vane from Coal Feed Valve A-4 ,
Impeller Back Plate from Leach Solution Circulation
2
, . 4
, . 10
. . 39
, . 40
, . 41
, . 42
, . 43
, . 44
45
. . 46
. . 47
. . 48
, . 49
. . 50
. . 51
. . 52
, . 53
54
, . 55
vl
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FIGURES (Continued)
Number
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
Rotor from Leach Solution Feed Pump P-13
Shaft P1ns from Leach Solution Feed Pump P-13
Bubble Cap Tray Inside Knockout Drum V-l
Weir Between Cells 1 and 2 of Mix Tank T-2
Weir Between Cells 2 and 3 of Mix Tank T-2
Agitator Blade from Cell 2 of Mix Tank T-2
Thermocouple Probe TE-21 from Cell 3 of Mix Tank T-2
Thermocouple Well Flange 1n Cell 3 of Mix Tank T-2
Rotor from Slurry Feed Pump P-l
Rotor End from Slurry Feed Pump P-7
Rotor Center from Slurry Feed Pump P-7
Intermediate Drive Shaft from Slurry Feed Pump P-7
Universal Linkage Shaft from Slurry Feed Pump P-7
Shaft P1ns from Slurry Feed Pump P-7
Retaining Ring from Slurry Feed Pump P-7
Pipe Flange which Mates with Slurry Feed Pump P-l
Discharge Port
Weir and Vessel Wall Inside Cell 4 of Primary Reactor R-l . .
Flange from Redrculatlon Loop for Cell 4 of Primary Reactor
R-l
Valve Body from Rec1rculat1on Loop for Cell 4 of Primary
Reactor R-l
Thermocouple Probe from Cell 5 of Primary Reactor R-l ....
Inlet to Redrculatlon Pump P-5
Outlet of Redrculatlon Pump P-5
Pump Housing from Redrculatlon Pump P-5
Page
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
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FIGURES (Continued)
Number
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
Impeller Back Plate from Redrculatlon Pump P-5 - Side View.
Impeller Back Plate from Redrculatlon Pump P-5 - End View .
Impeller from Redrculatlon Pump P-5 - Front View
Impeller from Redrculatlon Pump P-5 - Back View
Float Well for Level Monitor Gauge LT-58 from Cell 5
of Primary Reactor R-l
Interior View of Secondary Reactor R-l
Inlet Flange Face of Leach Solution Circulation Pump P-12. .
Outlet Flange Face on Leach Solution Circulation Pump P-12 .
Flange Face 1n Inlet Isolation Valve T4-28 to Tank T-9 ...
Flange Face on Reactor R-2 Manway
Flange Face on Inlet Spool to Leach Solution Pump P-13 ...
Flange Face from Leach Solution Feed Line to Foam Scrubber
T-3
Flange Face from Leach Solution Feed Line to Pump P-13 .
Disassemble Valve T4-6 from Filter Cake Wash Line to
Tank T-9
Lower Flange Face on Level Controller LC-39 for Knockout
Thermocouple Probe TE-148 from Knockout Drum V-1
Mating Flange to Thermocouple Probe TE-148
Page
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
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FIGURES (Continued)
Number Page
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
Flange Face on Process Line Mating with Heat Exchanger
E-2 Outlet
Flange Face on Manway Port on Cell 2 of Mix Tank T-2
Thermocouple Probe TE-21 from Cell 3 of Mix Tank T-2
Flange Face on Thermocouple Probe Port on Cell 3 of Mix
Tank T-2
Flange Face on Outlet of Slurry Feed Pump P-l
Flange Face on Outlet of Slurry Feed Pump P-7 ........
Flange Face from Slurry Feed Line to Cell 3 of Primary
Face of Flange Mating with Low Level Control Valve LV-59. . .
Flange Face on Inlet of Low Level Control Valve LV-59 ....
Flange Face on Outlet of Low Level Control Valve LV-59 . . .
Flange Face on Spool Separating Low Level Control Valve
LV-59 and Level Control KV-241
Flange Face on Inlet of Level Control Valve KV-241
Flange Face on Reactor R-l Cell 4 Discharge Line to Disposal
Tank T-9
Flange Face on Valve R4-52 in Cell 4 Recirculation Loop for
Seal Retainer Rings and Ball for Valve R4-50 from Cell 4
Recirculation Loop for Reactor R-l
Thermocouple Probe TE-56 from Cell 5 of Reactor R-l
Flange Gaskets from Heat Exchanger E-2
Flange Gaskets from Low Level Control Valve LV-59
Flange Gasket from Reactor R-l Cell 4 Sample Valve R4-76 . .
ix
^^K^B^B
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
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FIGURES (Continued)
Number. Page
87 Flange Gaskets from Steam Inlet Line to Cell 1 of Reactor R-l . 122
88 Flange Gasket from Filtrate Receiver V-2 Discharge Line. ... 123
89 Gravlchem Processing of TVA Coal 130
90 Size Distribution by Sieve Analysis of TVA Sink Coal 131
91 Pyr1t1c Sulfur Leaching Data from 1.3 S.G. TVA Sink Coal
(102°C Ambient Pressure) 133
92 Reactor Drawing 144
93 Process Flow Diagram 150
94 TEU Plot Plan 154
95 TEU Front Elevation 155
96 Tall End Unit Sketch 156
97 Gravlfloat Processing of an Ohio Waste Coal 171
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TABLES
Number Page
1 Test Plant Data Taken Over 5-Day Period 3
2 Specific RTU Shutdown Activities 13-16
3 RTU Preventive Maintenance Utilized During Shutdown. . . . 17-18
4 RTU Inspection Items 19-22
5 Settling Tank Float/Sink Separation/Analyses of
TVA (As Received) Coal 125
6 .Particle Size of Float and Sink Fractions of TVA Coal. . . 127
7 Float/Sink Separation/Analyses of TVA Coal 128
8 Rate Data on Processing 1.3 S.6. TVA Coal Sink
Fraction with 7.5* Iron Solution (4* H2S04) at 102°C
and Atmospheric Pressure .. . 129
9 Gob Pile Coal Samples 134
10 Gravl-Separation of Banner Gob Coal 135
11 Settling Tank Float/Sink Separation/Analyses of Gob
PlleCoals (14 Mesh) 137
12 Settling Tank Float/Sink Separation/Analyses of Gob
Pile Coals Peabody #2 Coal (As-Received) '38
13 Processing on Gob Piles Sink Fraction* @ 102°C
(Ambient Pressure) ...... .... 140
14 Processing of Peabody #2 Sink Fraction*
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TABLES (Continued)
Number Page
19 Utility Requirements .................... 153
20 TEU Equipment Design Basis Summary ............. 159-162
21 Equipment List and FOB COST* ................ 163-164
22 Estimated TEU Construction Costs .............. 165
23 Potential Sulfur Emissions of Coal Treated by Grav1chema
Process Compared with Deep Clean1ngb for High Sulfur
Coal Regions of U.S ...................
24 Sulfur Emissions Reduction Potential of Gravlchem Process
Compared with Deep Cleaning ..... .......... 169
25 Gravlfloat Coal 011 Slurry ................. ,170
26 Gravlfloat Process Results* ................ 172
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1.0 INTRODUCTION
The development of the Meyers Process for ferric sulfate leaching of
pyrlte sulfur from coal has been sponsored by the U.S. Environmental
Protection Agency through construction and operation of an eight ton per
day test plant (Figure 1) termed the Reactor Test Unit (RTU), at TRW's
San Juan Capistrano Test Site. This sponsorship was due to a desire to
evaluate a backup sulfur oxides emission control system for front-end con-
trol which would be especially applicable to the small utilities and
1nudstr1al boilers. The Meyers Process removes 95% of the pyritic sulfur
from coal leaving essentially only organic sulfur in the product. An
extensive laboratory test survey of U.S. coals showed that the process
could reduce the sulfur content of 1/3 of Appalachian coal to meet the
New Source Performance Standards then established by the Environmental
Protection Agency of 1.2 Ibs S02/10 Btu.
Operation of the test plant in 1977 and 1978 on an Appalachian coal,
supplied by the American Electric Power Service Corporation, showed that
the unit could be run continuously 1n three-shift operation to reduce the
sulfur content of the coal to meet the 1.2 standard (Table 1). Corrosion
problems were encountered in the main reactor which required modifications
prior to any further testing. Plant operation was then suspended and this
contract was awarded to provide corrosion assessment, specification of a
new main reactor, specification of a tall-end unit and maintenance of the
plant.
During the performance of the RTU project, the Gravichem modification
of the Meyers Process (Figure 2) was conceived in which coal is first
allowed to float and sink in the ferric sulfate leach solution, the float
product contains very little pyrlte and is washed free of iron sulfate and
is ready for use, while only the sink fraction (in which the pyrlte is
concentrated) is taken through the Meyers Process for removal of pyritic
sulfur.
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f\>
Figure I. Federal Energy Technology Test Facility Sponsored by U.S. Environmental
Protection Agency at TRH's San Juan Capistrano Test Site.
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TABLE 1 . TEST PLANT DATA TAKtN OVER 5-DAY PERIOD
Coal Analysis
Run Reactor Tenp. ,
°F
Starting Coal
1 222
2 232
3 234
Ash
% w/w
16.11
+0.26
12.97
+.0.89
12.02
+0.64
12.51
+0.95
Ht. Content
Btu/lb
12508
± 77
13258
+ 162
13388
+ 91
13265
+ 155
Sulfur
% w/w
1.73
+0.05
0.68
+0.04
0.78
+0.07
0.75
+0.03
Ibs S02
106 Btu
2.80
1 .03
1.17
1.13
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H2SO<
(SO,)
H20
HIGH SULFUR
COAL
FILTER
WASH
GRAVITY
SEPARATOR
(F.S,)
LOW SULFUR LOW
ASH COAL
Co O
REAaOR
I MEYERS PROCESS
L
SULFUR
LOW SULFUR
COAL
Fiqure 2. Gravichem Process.
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Use of the leach solution gravity separation technique in conjunction
with the Meyers Process results in an overall processing cost, including
capital amortization, of $12/ton with 93-96% overall energy efficiency.
This approach also led to a new and advanced method for physical cleaning
of fine or gob coal.
This present contract was awarded with tasks for the experimental and
applicability assessment of the Meyers Process.
The technical accomplishments of this contract modification for
Preservation of the Coal Desulfurization RTU and Bench-Scale Testing are
presented in the following sections:
Reactor Test Unit Inspection and Preservation;
Bench-Scale Extractions;
Specifications and Estimates for R-l Reactor Replacement;
RTU Acetone Extraction Unit and
Application Studies
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2.0 CONCLUSIONS
1. The inspection found the RTU to be in operating condition. However,
corrosion during operation had created a need for early replacement
of some equipment and components. The only condition of
immediate concern is the severity of corrosion in reactor R-l and
associated pumps and plumbing. Corrosion observed in certain
flanges and valve retainer seals (gasket sealing surfaces) and in the
leach solution and coal slurry feed pumps are of only minor concern.
These situations had been recognized earlier during RTU operation.
Potential solutions have been identified, but further operation of the
RTU will be needed to evaluate their effectiveness.
2. A replacement R-l reactor can be built of titanium with excellent
assurance of long-term serviceability.
3. Application of the Gravlchem Process to Eastern and Midwestern steam-
coal resources would reduce present oxides of sulfur emissions 1n the
United States by 45-58%.
4. The Gravifloat portion of the Gravichem Process can recover depyrlted,
very low-ash and low-sulfur fuel from waste coal fines such as slurry
ponds.
5. The Gravifloat coal in oil or water slurry is a potentially excellent
fuel for use in switching oil-fired boilers to coal.
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3.0 RECOMMENDATIONS
1. The Reactor Test Unit should be used for testing of a broad range
of coal desulfurization processes after refurbishment or replacement
of the R-l reactor.
2. Further near-term coal desulfurization studies should concentrate on
the removal of organic sulfur.
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4.0 REACTOR TEST UNIT INSPECTION AND PRESERVATION
4.1 INTRODUCTION
During 1977 and early 1978, TRW supervised design and construction,
and operated a Reactor Test Unit (RTU) designed to remove pyritic sulfur
from coal. The purpose of these efforts was to demonstrate successful
Meyers Process operabHUy at pilot plant scule and to provide data for
designing larger scale plants. In late January 1978, due to fiscal
considerations, operation of the RTU was suspended. This work was
sponsored by the Environmental Protection Agency (EPA) under Contract
68-02-1880.
In anticipation of restarting RTU operations in the future, EPA
requested that TRW preserve and maintain the RTU in a standby condition.
In addition to preparing and implementing a maintenance plan designed to
minimize system deterioration, an inspection of equipment for evidence of
corrosion and excessive wear was also to be conducted.
The purpose of this report is to document the maintenance plan as
well as present the results of the indepth plant inspection. A brief
description of the RTU and its operating history is provided as background
The actions taken to place the RTU in a standby mode are discussed as is
the plan which has been implemented to minimize deterioration. The equip-
ment inspected for corrosion and wear and the findings of the inspection
are described.
4.2 BACKGROUND
The Meyers Process is a chemical process for removing pyritic sulfur
from coal. The coal is mixed with an aqueous solution of ferric sulfate.
This slurry is then heated to 100-130°C where the ferric sulfate oxidizes
the pyritic sulfur in the coal to form elemental sulfur and additional
iron sulfate. At the same time oxygen is introduced into the aqueous
solution to regenerate the spent ferric sulfate. The aqueous solution
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dissolves the iron sulfate and the elemental sulfur is removed by solvent
extraction. The coal is dried and the solvent recovered. The by-products
of the process are iron sulfate, which may be limed to give a dry gypsum
and iron oxide material, and elemental sulfur. Both are safe, storable
materials.
A three to eight tons per day Reactor Test Unit (RTU) is located at
the TRW Capistrano Test Site. Its purpose is to demonstrate those unit
operations which make up the front end of the Meyers Process: coal-leach
solution mixing, pyrite reaction, leach solution regeneration, and slurry
filtration.
A simplified process flow sheet for the RTU is shown in Figure 3.
Coal which has been ground to the desired size is loaded into the storage
tank, T-l. The live bottom feeder, A-2, continuously feeds the coal onto
the weigh belt, A-3, which in turn discharges the coal through a rotary
valve, A-4, into the three-stage mixer T-2 (stream 1). The aqueous leach
solution feed (stream 2) enters T-2 after being preheated in heat exchanger
E-2 and passed through the foam scrubber T-3. Steam from stream 3 is added
to T-2 to raise the coal-leach solution slurry to its boiling point.
The heated slurry is pumped through stream 4 to a five-stage pressure
vessel, reaction R-l, in which most of the pyritic sulfur is removed from
the coal. Heating is achieved by direct injection of steam into each
reactor stage. Oxygen from stream 5 is also injected into each stage to
regenerate the leach solution. Unused oxygen saturated with steam exits
the reactor through stream. 6 and is scrubbed in the foam knockout V-l with
feed leach solution from stream 7.
The reacted coal slurry which is at elevated pressure and temperature,
exits R-l through stream 8 and is flashed into T-5. The steam generated
in T-5 as well as vent gases from V-l and T-3 are water scrubbed in T-4.
The condensate and any entrained acid mist are removed with the return
water.
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II COAl
W MECHANICAL
ATMOS.
WATtl
?r
p-n
TO UUCK FO« OISPOSAI
Figure 3. RTU Schematic.
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The reacted slurry is fed through stream 10 to the belt filter S-l.
The filtrate (regenerated leach solution) removed from the coal is collected
in the evacuated filtrate receiver V-2 and is pumped through stream 12 to
one of two leach solution storage tanks, T-7 or T-8. Coal on the filter
belt is washed with water from stream 11 and discharged to coal storage
bins. The wash water is collected in the wash water receiver V-3 and
pumped through stream 13 to the liquid waster tank T-9.
Upon completion of RTU shakedown, operational testing was initiated
on 1 October 1977. During the next four months, the unit processed 49,700
pounds of coal over approximately 250 hours of operation. Sufficient data
was acquired to verify the process chemistry and reaction rates, to
parametrically evaluate process variables, to determine equipment operating
characteristics, and to generate sufficient coal quantities for vendor
testing. Operational testing was suspended on 26 January 1978.
4.3 ROUTINE MAINTENANCE DURING STANDBY
During early February 1978, the RTU coal desulfurization unit was
secured for an extended shutdown period. The extent of the shutdown period
was anticipated to be six to twelve months. TRW was requested to maintain
the plant in a standby mode thus necessitating the continued lease of
critical support equipment and the implementation of a minimum preventative
maintenance program.
In order to secure the RTU and insure minimum damage to system com-
ponents during the shutdown period, the following tasks were completed.
• Most RTU systems on-site were cleaned of residual acid and
coal by flushing with water (some residual coal may still be
in unaccessible lines). All tanks on the test stand were
flushed and all pumps drained. Where equipment suppliers
directed, preservatives (i.e., oils or inhibitors) were added
to protect against corrosion.
11
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• Electrical switches and breakers on decommissioned equipment
were shut off, tagged and the main breakers thrown (off) and
tagged. Guards on pumps were removed to permit periodic
hand rotation (once a week) of the pump equipment.
• All Instrumentation (i.e., Doric, Transducers, Flowmeters,
and Level Devices) were sealed and desiccant added to keep
moisture from contacting the equipment.
o The boiler was shut down and thoroughly dried to protect
the rental equipment against corrosion.
• All liquid wastes (leach solution, dilute sulfurlc acid,
and waste water) were hauled away to the proper disposal
areas by an outside contractor. The solid wastes (pri-
marily processed coal) were hauled away to disposal also.
• Reactor R-l was visually inspected and corrosion specimens
removed for evaluation.
• Instrument air is being utilized to protect the Taylor
Oxygen Analyzer AE-171 and the Autoweigh System A-3. No
LNp supply has been maintained during shutdown. Residual
feed coal in T-l was removed and stored in two tote bins.
The tanks in the tank farm were drained and manways opened.
• Twenty barrels of filter cake have been sealed, labeled,
and stored in the RTU storage area.
A detailed listing of the specific shutdown related operations which were
carried out is presented in Table 2. The table 1s divided Into two groups,
mechanical equipment related activities and those associated with
Instrumentation/electrical RTU components.
During the shutdown period, a minimum scheduled preventative main-
tenance program 1s being conducted. Those activities which are carried
12
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TABLE 2. SPECIFIC RTU SHUTDOWN ACTIVIES
Mechanical Related
1. Cleaned out all piping, pumps, and valves in the RTU system and
flushed with water to remove acid and coal.
2. Drained R-l primary reactor and pumped slurry to tank T-9 in the
tank farm.
3. Drained T-2 mixer of all slurry and pumped to tank farm.
4. Shut down all pumps and lubricated all parts of motors and
bearings (P-l through P-16).
5. Performed special cleaning of K-l vacuum pump and added corrosion
inhibitor.
6. P-15 pump flushed with clean water and Isolated with feed valve
open.
7. Air compressor serviced and lubricated.
8. Doric shutdown for standby - batteries disconnected from unit.
9. Trailer (control center) leased for standby - roof retarred.
10. Boiler, LPC tanks (2), LN2 tank leased for standby.
11. Forklift and liquid 02 tank were returned to supplier and leases
terminated.
12. Dumpsters (4) and waste bins (2) were returned to supplier and
contract terminated.
13. Dumped coal from T-l coal storage tank into tote bins.
14. Cleaned autoweigh system and purged with air.
15. Flushed all tanks and drained prior to applying N? blanket
for standby.
(Continued)
13
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TABLE 2. (Continued)
Mechanical Related (Continued)
16. Removed corrosion samples from R-l primary reactor cell 3 and
Inline orifice specimens 1n recirculating loops.
17. Lubricated mixers.
18. Stencilled 20 coal product barrels with permanent labels.
19. Locked up all tools and special equipment in control center.
20. Inventoried all unlnstalled parts, spares, etc.
21. Deactivated Op analyzer, purged with Ng and isolated.
22. Cleaned V-l, V-2, and V-3.
23. Locked up all safety gear 1n the RTU storage shed.
24. Returned all cylinders for air breathing equipment.
25. Returned all cylinders of ultra pure 02 to supplier.
26. Placed all bottled sulfuric acid in storage shed.
27. Cancelled all outstanding purchase orders.
28. Finished the fabrication of a Hasteloy C pump rotor and installed
in P-l.
Instrumentation/Electrical Related
1. Control Console
t Removed front panel of microprocessor and turned emergency
battery power switch to off. Replaced front cover and turned
off 115 VAC power.
• Disconnected all 115 VAC power busses in control console
from floor outlets. Colled up all extension cords and
connectors and stored in console.
(Continued)
14
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TABLE 2. (Continued)
Instrumentation/Electrical Related (Continued)
2. Oxygen Analyzer
• Plumbed instrument air to the inlet (downstream of remote
solenoids) of the reference and sample cells.
• Set reference cell to reference and sample cell to sample.
• Set internal cabinet heat control for 70°F.
• Tagged breaker 16 on LP-1 to read: "Do Not Turn Off Before
Contacting W. Bowes/J. Hunt".
3. Autoweigh
• Closed supply valve between autoweigh and T-l tank.
• Installed a blanking piece of metal between autoweigh discharge
chute and T-2 inlet.
• After autoweigh was cleaned and the cabinet resecured, plumbed
instrument air into the existing N2 purge point on the discharge
duct.
4. Electrical 115 VAC Power
e Turned off individual breakers located by the following instruments
instruments: FE-31, FE-83 through FE-87, FE-29, FE-101, FE-157,
and FE-158.
• Turned off all breakers on LP-1 except 16.
5. Level, Steam, and Pressure Controllers
e Closed all N2 supply valves to LI-26, LI-58, LC-39, PIC-43,
LI-95, LC-107, and LC-108.
• Installed Humi Sorb desiccant bags in the following controllers
and, utilizing masking tape, taped all door-to-cabinet seams:
LT-26, TIC-32, LC-39, LI-58, PIC-43, LI-95, TIC-102, LC-107,
LC-108, LI-130 through LI-132.
(Continued)
15
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TABLE 2. (Continued)
Instrumentation/Electrical Related (Continued)
6. Motor Control Center, MCC-100
• Turned off all breakers, except IE, 6C, 7DL, 7AL, 7AR, and 9AR
7. Emergency Lighting
• Disconnected charger from 115 VAC source.
e Disconnected emergency lights from battery.
out are delineated 1n Table 3. As may be seen, the scheduled maintenace
program has, as its primary objective, the preservation of all major
rotating equipment. The tabulated maintenance program has been utilized
since early February 1978.
4.4 RTU INSPECTION AND INSPECTION RESULTS
An inspection of the RTU conducted in December 1977 revealed that
reactor R-l and its associated piping had experienced crevice corrosion
of varying degrees. However, leach solution feed lines, the slurry mix
tank T-2, the flash-drum T-5, and reactor-regenerator pumps were unaffected,
The reactor was repaired, the associated piping replaced and the RTU
operation was continued. The extent of the December 1977 inspection was
a cursory nature being limited by program pressures to continue process
evaluations. The current lull in RTU operations has provided an
opportunity to perform a more complete Inspection.
Since complete disassembly and inspection of the entire RTU would be
impractical, the 65 items listed in Table 4 were selected for inspection.
The selection of these items was such that their observed condition would
be an indication of the overall condition of the RTU. The selected items
included major equipment, valves, piping, thermocouple probes, and flanges
from various locations. They provide a basis for judging which areas
within the RTU are prone to corrosion.
16
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TABLE 3. RTU PREVENTIVE MAINTENANCE UTILIZED DURING SHUTDOWN
1. Trailer - Air conditioner
check (70-75°C) operating
2. Maintain pumps by rotating
by hand - 180°C (to prevent
flat spot on bearings)
P-2 Recir. pump
P-3 Recir. pump
P-4 Recir. pump
P-5 Recir. pump
P-6 Recir. pump
P-9 Filtrate pump
P-10 Wash pump
P-12 Leach solution pump
P-14 Waste disposal pump
P-15 Cooling water pump
3. K-l Vacuum pump (rotate)
by jogging pump electri-
cally three times to pre-
vent flat spots. (No
liquid required.)
4. Air compressor
o Operate at pressure
of 90-110 psi
• Drain air drier on
compressor
5. LN2 - Tank 103
L02 - Tank 102
Dally
Weekly
X
X
X
X
X
X
X
X
X
X
By Whom
NONE REQUIRED
SOR
TRW M
TRW M
TRW M
TRW M
TRW M
TRW M
TRW M
TRW M
TRW M
TRW M
TRW M
TRW M
TRW M
(Continued)
17
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TABLE 3. (Continued)
Daily Weekly By Whom
6. Cooling water pond
e Water level X TRW M
• Water condition X TRW M
7. Oxygen analyzer
• Cabinet heaters X TRW M
• Gas throughout X TRW M
Note:
SOR - TRW security personnel on their normal rounds.
TRW M - Assigned TRW Maintenance servicemen.
For the purpose of this report, the RTU has been divided Into eight
systems. Each system represents a different process function. Each has
its own set of operating conditions in terms of temperature, pressure, and
process fluid composition. The process conditions, the Items inspected,
and the inspection results for each process area are discussed 1n Sections
4.4.1 through 4.4.8.
To facilitate assembly and disassembly of equipment, gasketed joints
were used throughout the RTU. Deterioration of some of the gasket material
and corrosion of the sealing surfaces were found during the Inspection.
Since the anomalies appear to be related and because their occurrence
appears to be independent of location within the RTU, they are discussed
as a separate subject In Section 4.4.9.
During the course of the Inspection activity, components removed and
Inspected were either left out of the RTU or reinstalled. Those items
left out of the system have been tagged and stored in the equipment trailer.
The associated connecting flanges were sealed with tape to preclude the
18
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TABLE 4. RTU INSPECTION ITEMS
Number Description
1 Hoist SP-2
2 Bin Tilt Mechanism
3 Lined Switch LSL-8 in Coal Storage Tank T-l
4 Coal Storage Tank T-l
5 Rubber Collar between Coal Storage Tank T-l and Live
Bottom Feeder A-2
6 Rubber Collar between Live Bottom Feeder A-2 and Weigh
Belt A-3
7 Weigh Belt A-3
8 Rotary Valve A-4
9 Water Cooled Duct between Rotary Valve A-4 and Slurry
Mix Tank
10 A Section of Process Line AA-1 between Slurry Mix Tank
T-2 and Foam Scrubber
11 Leach Solution Flow Meter FE-31
12 A Section of Process Line between the Leach Solution
Flow Meter FE-31 and the Foam Scrubber T-3
13 Level Transmitter LT-26 in Slurry Mix Tank T-2
14 Slurry Mix Tank T-2
15 Mixer M-3 in Cell 3 of Slurry Mix Tank T-2
16 Sample Valve M4-8 on Cell 3 of Slurry Mix Tank T-2
17 Thermocouple Probe TE-21 in Cell 3 of Slurry Mix Tank T-2
18 Slurry Feed Pump P-l
19 Slurry Flow Meter FE-101
20 A Section of Process Bins AA-7 Downstream of Slurry Flow
Meter FE-101
(Continued)
19
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TABLE 4- (Continued)
Number Description
21 Valve MA-16 In-Process Bins Between Slurry Mix Tank
T-2 and Waste Disposal Tank T-9
22 Valve MA-15 In-Process Line Between Slurry Mix Tank T-2
and Primary Reactor R-l
23 Leach Solution Heat Exchanger E-2
24 Slurry Feed Line AA-5 to Cell 3 of Reactor R-l
25 Slurry Feed Line AA-6 to Cell 1 of Reactor R-l
26 Knockout Drum V-l
27 Level Switch LSL-31 in Knockout Drum V-l
28 Level Controller LC-39 for Knockout Drum V-l
29 Oxygen Analyzer AE-171
30 Steam Feed Line AA-4 to Cell 1 of Reactor R-l
31 Cell 3 of Reactor R-l
32 Sample Valve on Cell 4 of Reactor R-l
33 Level Controller LT-48 on Cell 5 of Reactor R-l
34 Level Switch LSL-59 1n Cell 5 of Reactor R-l
35 Thermocouple Probe TE-54 for Cell 3 of Reactor R-l
36 Thermocouple Probe TE-55 for Cell 4 of Reactor R-l
37 Thermocouple Probe TE-56 for Cell 5 of Reactor R-l
38 Low Level Valve LV-59 in Slurry Discharge Line from
Cell 5 of Reactor R-l
39 Slurry Control Valve KV-241 1n Discharge Line from
Cell 5 of Reactor R-l
40 Gas Flow Meter FE-44
41 Thermocouple Probe TE-148 from Gas Effluent Line
42 Pressure Control Valve PV-43
(Continued)
20
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TABLE 4. (Continued)
Number Description
43 Flow Meter FE-83 in Recirculation Loop for Cell 1
of Reactor R-l
44 Flow Meter FE-84 in Recirculation Loop for Cell 2
of Reactor R-l
45 Flow Meter FE-85 in Recirculation Loop for Cell 3
of Reactor R-l
46 Flow Meter FE-86 in Recirculation Loop for Cell 4
of Reactor R-l
47 Flow Meter FE-87 in Recirculation Loop for Cell 5
of Reactor R-l
48 Recirculation Loop Plumbing for Cell 4 of Reactor R-l
49 Level Switch LSH-88 on Flash Drum T-5
50 Secondary Reactor R-2
51 Slurry Feed Pump P-7
52 Belt Filter S-l
53 Filter Belt Wash Pump P-8
54 Filtrate Pump P-9
55 Vacuum Pump K-l
56 Filtrate Line AA-8 between Filtrate Receiver V-2 and
Filtrate Pump P-9
57 Leach Solution Storage Tank T-7
58 Leach Solution Storage Tank T-8
59 Liquid Waste Storage Tank T-9
60 Leach Solution Circulation Pump P-12
61 Leach Solution Feed Pump P-13
62 Basket Strainer SP-11
(Continued)
21
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TABLE 4. (Continued)
Number Description
63 Leach Solution Feed Line AA-3 Between Basket Strainer
SP-11 and Leach Solution Feed Pump P-13
64 Valve T4-28 1n Inlet Line to Liquid Waste Storage
Tank T-9
65 Valve T4-6 in discharge line between Filter Cake Wash
Pump P-10 and Liquid Waste Storage Tank T-9
introduction of foreign objects, insects, etc. No attempt was made to
reseal flange joints upon reinstallation of components or equipment.
Gaskets will have to be replaced and the flange joint sealed and leak
checked. To assist prestart-up operations, the reinstalled joints have
been tagged.
Figures 4 through 17 show the condition of the RTU after the dis-
assembly inspection. The control console is shown in Figure 4 while a
view of the west side of the RTU stand is shown 1n Figure 5. Views of the
oxygen analyzer and bin tilter can be seen in Figures 6 and 7. The next
two figures (Figures 8 and 9) show the equipment on level 4: the top of
the coal feed tanks T-l and T-6, the knockout drum V-l, the vent gas
scrubber T-4, and their associated plumbing, valves and Instrumentation.
Figure 101s a view of the bottom of the coal feed tanks and the weigh
belt feed A-3. General views of the mix tank T-2, the primary reactor R-l,
and the belt filter S-l, are shown in FiguresTl through 14, Figures 15
and 16 show the filtrate collection equipment and the recirculation pumps
for T-l, respectively. Figure 17 looks down on the north end of the tank
farm. Tanks T-7 and T-8 and the mounting platforms for pumps P-12 and
P-13 are shown. The various pictorial views of the RTU in essence show the
current condition of the facility.
22
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4.4.1 Coal Feed System
Feed coal is received from a subcontractor grinding facility in steel
bins. These bins are hoisted to the top of the RTU test stand and emptied
by a pneumatic bin tilter A-l. The coal is routed through a duct to the
coal storage tank T-l. A vibrating, live bottom feeder, A-2, at the
bottom of T-l prevents solids bridging and maintains coal flow to the
weigh belt A-3. The coal is discharged from A-3 through a rotary valve
into a water cooled duct which leads to the coal-leach solution mixer T-2.
During operation, the bin tilter, storage tank, weigh belt, and
ducting are maintained at a positive pressure with nitrogen (Np) to pre-
clude oxygen or moisture contaminating the feed coal. The coal bins are
also pressurized with N2 at the time of the filling for the same reason.
No attempt is made to heat or cool any of this equipment; 1t operates at
ambient temperature.
During RTU operations, two coal bins would not mate properly with the
hoist attach mechanisms. The attaching Interface structure at the top of
these bins appears to have been bent. Consequently, these bins cannot be
lifted by the hoist. Visual Inspection indicates that the remaining 73
bins are serviceable.
The electrically operated hoist undergoes semi-annual inspection and
load tests as required by the safety code. During the last Inspection,
the hoist was found to be Inoperable. There is an open circuit in the
hoist control circuit.
The bin tilter A-l is equipped with a T-handle wrench for opening the
bin discharge port after the coal bin has been placed on the bin tilter.
The cloth boot sealing the wrench to the tUter 1s worn and may leak coal
dust during coal discharge operations. Otherwise the bin tilter appears
to be in good condition.
The eight-inch diameter at the top of T-l was opened and the interior
of the coal feed tank Inspected. The low level alarm switch LSL-8 was
23
-------
also removed. No visual anomalies were observed.
The rubber collar connecting the live bottom feeder A-2 to the coal
feed tank is cracked approximately 50% around its circumference (see
Figure 18). However, the rubber collapse between the live bottom feeder
and the weigh belt A-3 is not damaged.
Visual inspection of the weigh belt mechanism inside its cabinet
revealed only slight rust on the belt adjustment bolts. However, the seals
for the access door cover and windows have deteriorated and will probably
need replacing prior to reinitiation of plant operations.
The rotary valve A-4 was removed from the drive unit and the bearings
were checked for both side and end play. None was found. The clearances
between the rotor vanes and the valve body are not badly worn. However,
one of the vanes is bent (see Figure 19). The damage was undoubtedly
caused by some foreign object being caught between the rotor and the valve
body while the valve was in operation.
The water cooled duct between the rotary valve A-4 and the slurry mix
tank T-2 was found to be in good condition with no visible corrosion
present.
4.4.2 Leach Solution and Waste Liquid Storage System
This system consists of the three large storage tanks T-7, T-8, and
T-9 as well as the leach solution circulation pump P-12 and the piping,
valves, etc., generally located in the tank farm. The process environments
experienced by this equipment are ambient temperature and pressure.
The manways on tanks T-7, T-8 and T-9 were opened and the tank
interiors inspected. The manway seals and tank internal components are in
good shape. The floors of T-7 and T-8 are coated with a reddish brown
residue approximately 1/4-inch thick. Since these tanks contained either
fresh or recovered leach solution, then residue is probably residual iron
sulfate left after the tanks were drained.
24
-------
Tank T-9 was used to collect the coal wash liquid from the S-l filter
and the material flushed from the RTU during shutdown operations. The
bottom of the tank is coated with coal fines and what appears to be ele-
mental sulfur or yellow-boy sulfate deposited from evaporated residual
liquid. The internal walls are also coated to a height of approximately
15 feet with what appears to be an opaque substance which resembles tar.
When the drain plug was removed from the bottom of the leach solution
circulation pump P-12, approximately one cup of liquid was removed.
Subsequent disassembly inspection revealed minor surface etching on the
lower one-fourth of the impeller housing and impeller back plate (see
Figure 20). The impeller, the shaft, and mechanical shaft seal are in
good shape.
Since the pump backing plate and impeller housing were etched only on
the lower 1/4 of the surface, it is believed that the residual liquid was
the cause.
The isolation valve T4-28 on the inner line to T-9 as well as a
Jamesbury valve T4-6 1n the line from the wash water receiver V-3 to T-9
were disassembled and inspected. Some coal and salt residue was found in
the T4-28 valve cavity. Slight crevice corrosion was also found on some
of the gasket seal surfaces. This type of observations is discussed 1n
detail in Section 4.4.9 of this report. No other defects were found.
4.4.3 Leach Solution Feed System
During the RTU operation, pump P-13 is used to pump leach solution
from T-7 or T-8 through a strainer S-ll to the knockout drum V-l where
the leach solution is used to break down any foam and demist the vent
gases from reactor R-l. The leach solution is then fed through heat ex-
changer E-2 for preheating to 170°C and then into the foam scrubber T-3.
The leach solution is used in T-3 to break down any foam generated during
the mixing of leach solution with the coal 1n T-2. The leach solution is
gravity fed from T-3 to the first stage of the T-2 mixer. Leach solution
feed rates are monitored by a magnetic flow meter FE-31 located betweeen
the heat exchanger E-2 and the foam scrubber T-3.
25
-------
The leach solution leaving the storage tank may or may not contain
any dissolved oxygen depending upon whether the solution has been used in
a previous run or is a fresh batch. In either case the solution is assumed
to become nearly saturated at ambient temperature with oxygen in V-l.
Solution temperature is subsequently raised to approximately 170°F in the
heat exchanger and remains near that temperature until it reaches the mix
tank T-2.
The items Inspected Included strainer SP-11, the process line AA-3
between the strainer and the pump P-13, the knockout drum V-l, the solution
level controller, LC-39 and the low level alarm sensor LSL-37 on V-l, the
heat exchanger E-2, the flow meter FE-31, a short section of process line
AA-2 immediately down stream of the flow meter, and a section of the leach
solution discharge line AA-1 from T-3.
The basket strainer SP-11 and the process line AA-3 from the strainer
to pump P-13 appears to be in very good condition. No evidence of corrosion
(except that reported in Section 4.4.9) or other anomalies were found.
As noted 1n the final report, EPA-600/7-79-013a, "Reactor Test Project
for Chemical Removal of Pyritic Sulfur from Coal," dated January 1979,
pump P-13 experienced a rotor related problem near the end of RTU operation.
Disassembly inspection at that time revealed that the chrome plate on the
rotor had crazed and flaked off (see Figure 21) Increasing the clearance
between the rotor and pump stator. This excess clearance permitted back
flow of the leach solution and thereby limited the pumping capability.
The P-13 rotor was replated with chrome and placed back Into service. A
new rotor was also fabricated from 316L stainless steel (unplated) for use
as a spare.
The most recent Inspection shows the pump stator and replated rotor
to be in a good condition. There is no evidence of corrosion, and a "tight11
fit still exists between rotor and stator. This tight fit indicates that
the stator has not worn appreciably. The outside diameter of the rotor
(lobe-to-lobe) measures 1.875 Inches. This 1s within the tolerances for
26
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a new rotor. However, the surfaces of the shaft pins which are normally
exposed to the leach solution are corroded. The condition of these pins
are shown in Figure 22.
The knockout drum V-l as well as the solution level controller LC-39
and low level switch LSL-37 are also in very good condition. However,
the bubble cap trays are jammed in place and could not be removed without
first removing V-l from the RTU structure. Because the internal surfaces
visible from the top of V-l are in excellent condition with no signs of
corrosion (see Figure 23), it was decided not to remove V-l from the RTU
stand for further disassembly.
The Internal surfaces of heat exchanger E-2, flow meter FE-31 and
the process pipes AA-2 and AA-1 are in excellent shape. No evidence of
corrosion or other anomalies were found.
4.4.4 Coal Slurry Preparation System
The equipment 1n this portion of the RTU consists of the slurry mix
tank T-2, a slurry feed pump P-l, a flow meter FE-101, and the piping
which connects these pieces of equipment and subsequently leads to reactor
R-l.
The mix tank T-2 contains three cells each equipped with a propeller
blade mixer, steam Injection port, and a thermocouple well. The cells
are separated by overflow wlers which can be raised and lowered to con- .
trol the volume of slurry contained the first two cells.
Both leach solution at 170°C and dry coal at ambient temperature are
continuously fed Into cell 1. The slurry Is heated by direct steam
injection Into each cell. The temperature 1n the three cells 1s typically
180°F, 205°F, and 215°F (cells 1 through 3, respectively). The heated
slurry is discharged from cell 3 through the slurry pump P-l to either
cell 1 or cell 3 of reactor R-l. A level control sensor LT-26 controls
the speed of P-l so that the volume of slurry in cell 3 of T-2 is held at
a predetermined level. The flow meter is located between P-l and R-l.
27
-------
The pressure in the system is atmospheric until the solution reaches P-l
where it is increased to the operating pressure of the reactor R-l,
typically 50 to 100 psig.
The disassembly inspection of the slurry mix tank T-2 consisted of
opening the manway into cell 2 and removing the thermowell TE-21, the
sample valve M4-8 and the level controller LT-26 from cell 3. This hard-
ware is in very good condition. The mixer shaft and blades as well as the
baffles between the cells do not have any evidence of corrosion (see
Figures 24 and 25). However, the agitator blade shows evidence of slight
mechanical abrasion as shown in Figure 26. The portion of the level
controller that extends into the mix tank shows no evidence of corrosion.
There has been some mechanical abrasion of the tube, but only to the point
of brightening the surface. There are two small corrosion pits near the
end of the thermowell probe on TE-21 removed from cell 3. These are in
the weld material rather than in the parent material (see Figure 27).
There also are small corrosion pits in the weld material connecting the
thermocouple well flange to the T-2 tank wall. These are shown in Figure
28. The sample valve M4-8 taken from cell 3 was also disassembled and
visually inspected. No corrosion or other anomalies were found.
The results of the disassembly inspection of both slurry feed pumps
are reported here. The two pumps are identical and have seen approximately
the same length of service functioning as P-l, i.e., pumping hot coal
slurry from mix tank T-2 to reactor R-l. The flow sheet in Figure 3 shows
P-7 as the discharge pump for reactor R-2. However, P-7 was used very
little in this capacity.
During RTU operation, both pumps experienced the same difficulties
experienced by the leach solution feed pump P-l3, I.e., erosion and
corrosion of the chrome plate on the rotors. However, in the case of the
slurry pumps, the rotor SS-316L base material eroded and corroded causing
loss of pumping capability. The cause of this additional erosion/corrosion
1s believed to be the abrasive nature of the coal slurry as opposed to the
liquid leach solution handled by P-13.
28
-------
The rotors from both P-l and P-7 were replated to the required
tolerances with chrome plate. P-l was put back Into service and performed
satisfactorily for several hours before the chrome plate flaked off causing
pump failure. Figure 29 shows the flaked condition. The thicker chrome
plate could not withstand the thermal expansion from ambient to operating
temperatures. Near the end of RTU operation, a new rotor was fabricated
of Hastelloy C-276 and Installed 1n P-l. P-7 equipped with a replated
rotor was 1n service at the end of RTU operation
As expected, P-l 1s 1n very good condition. The only sign of
excessive wear 1s on a retaining ring for the pin at the small end of the
rotor shaft. Measurements show that the diametrical clearance between the
shaft and the retaining ring 1s .011 Inches. It should be .001 Inches.
Also as expected, the internal parts of pump P-7 show evidence of
corrosion and wear. Figures 30 and 31 show the wear and corrosion at the
drive end and the center section of the rotor. The Intermediate shaft is
etched in the area of the Up seal (see Figure 32). The universal linkage
shaft 1s severely etched (see Figure 33). The shaft pins and pin retain-
ing ring are also corroded (Figures 34 and 35, respectively).
The weld material conncectlng the flange, which mates the P-l dis-
charge port with the downstream process line, 1s corroded (Figure 36).
The corrosion 1s similar 1n type and extent to that found in the weld
material connecting the thermocouple well flange to the T-2 vessel wall.
The flow meter FE-101, which measures the slurry flow rate from the
mix tank T-2 to the reactor R-l, and the process line Immediately down-
stream of the flow meter were removed, disassembled, and Inspected. The
process line Included two ball valves, M4-15 and M4-16. The teflon line
Inside the flow meter had extruded slightly at the flanges. The flow
straightness Insert at the Inlet to the flow meter had some corrosion pits.
Neither condition has progressed enough to be of any concern. Except for
very minor crevice corrosion on gasket seal surfaces (discussed in Section
4.4.9 of this report), the process line and ball valves are in excellent
29
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condition. This is also true for slurry feed lines and valves leading to
cell 1 and cell 3 of reactor R-l which were removed and inspected.
4.4.5 Primary Reactor System
The primary coal reactor R-l is a horizontal pressure vessel 38 inches
in diameter and 14.75 feet long. It is divided into five cells by sta-
tionary weirs which are 28.5 inches high. Each cell 1s equipped with a
variable speed agitator and a slurry recirculation system. Hot slurry may
be fed into either cell 1 or cell 3 and overflows into each succeeding cell
unit until it reaches cell 5. The reacted slurry is discharged from cell
5 through a discharge valve KV-241 into the flash drum T-5. A buoyant type
level gauge is used to monitor the slurry level in cell 5.
The slurry recirculation system for each reactor cell withdraws slurry
from the cell, into a process line, through a centrifugal pump, and then
returns to the same reactor cell. Reactor heating and slurry oxygenation
are performed by injecting steam and oxygen into each slurry recirculation
loop. Excess gases vent through a vent line leading from the top of the
reactor to the knockout drum V-l. Reactor pressure 1s maintained by a
pressure control valve and 1s monitored by a pressure transducer located
in the gas vent system described later.
Each reactor cell 1s equipped with a thermocouple probe for monitor-
ing slurry temperatures. Each cell and each recirculation loop also have
a one-inch sampling port for withdrawing slurry samples for chemical
analyses. The reactor R-l and associated equipment 1s subjected to tem-
peratures up to 275°F and to oxygen dissolved in the slurry.
As reported 1n the final report cited earlier, the reactor vessel,
the reactor Internals, and the slurry recirculation loop equipment experi-
enced progressively severe corrosion, both crevice corrosion and pitting.
The severity of the corrosion led to the recommendation to replace the
reactor system with new reactor, piping, flanges, and valves constructed
of titanium. The recommended material of construction 1s predicted not
only by the results from materials study (also reported 1n the final report
30
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but also by the size of the equipment. The RTU reactor and piping are too
small for metallic, elastomer, and/or add brick lining to be applicable.
The recommendation Is also based upon the relative low cost of titanium
replacement parts. For example, a quote of $49,300 was obtained 1n January
1978 for a replacement titanium reactor vessel. The original non-t1tan1um
(stainless steel) reactor cost $25,900 1n early 1976.
Figure 37 shows examples of the corrosion 1n cell 3 of the reactor.
The severity 1s progressively worse 1n cells 4 and 4. Figures 38 through
40 show examples of pitting corrosion found 1n piping, valves, and on
thermocouple probes. It should be noticed that these Items were Installed
new 1n December 1977.
The centrifugal pumps 1n the slurry reclrculatlon loops had not been
disassembled during the previous Inspections of the reactor system. There-
fore, pump P-5 (servicing cell 4) was subjected to a disassembly Inspection
this time. The pump parts which had been exposed to the slurry show
evidence of significant corrosion. Some of the corrosion can be seen 1n
Figures 41 through 48. The corrosion on the pump Impeller shown 1n Figure
45 appears to be associated with casting flaws. Figure 48 shows the eroded
and etched surface found on the pump shaft.
The low level alarm switch LSL-59 and the level monitor gauge LT-58
were removed from cell 5 of the reactor and Inspected. The only corrosion
found was some pits on the outside diameter of the float well shown 1n
Figure 49. The flow meter FE-86 1n the reclrculatlon loop for cell 4 was
also found to be 1n excellent shape. The teflon Uner was not deformed.
There were no signs of leakage through the Uner.
4.4.6 Gas Vent System
The vapor spaces of each of the three cells of the slurry mix tank
T-2 are vented to the foam scrubber T-3. The vent gases are passed through
a bubble cap tray flooded with hot leach solution to break up any foam
which might be generated 1n the mix tank. Gases from the foam scrubber T-3
(predominately nitrogen from purge lines 1n the coal feed system) are
31
-------
vented to the vent gas scrubber T-4. The line from cell 1 of the mix tank
T-2 and the foam scrubber T-3 was removed and inspected. No evidence of
corrosion was found.
The vapor space in the primary reactor R-l is vented to the knockout
drum V-l where the vent gases are contacted with unheated leach solution.
This removes any steam or acid mist that might be entrained. The gases,
predominently oxygen, exiting the knockout drum V-l, are vented to the
vent gas scrubber T-4. The instruments that monitor and control the
pressure In the knockout drum V-l and the primary reactor T-l as well as
monitor the flow rate, temperature, and oxygen content of the vent gas
from the reactor R-l are located in the vent line between the knockdown
scrubber V-l and the vent gas scrubber. The flow meter FE-44, the thermo-
couple probe TE-148, and the pressure control valve PV-43 were removed
and inspected. No anomalies were found. Some traces of particulate con-
tamination (coal fines and evaporation residue) were noticed.
The oxygen analyzer AE-171 also appears to be in excellent condition.
The interior of the cabinet is clean and no deterioration of flow lines
and instruments could be detected.
All of the vent gases from the RTU pass through the vent gas scrubber
T-4. It is here that the gases are washed with water from a spray head to
remove any steam vapors or acid mist which might travel this far. Because
this scrubber is constructed of fiber reinforced plastic and because the
operating condition is benign, no inspection was made of this piece of
equipment.
4.4.7 Secondary Reactor System
The secondary coal reactor R-2 is a 365 gallon, vertical tank equipped
with a variable speed agitator, a level sensor LT-95, and a thermocouple
probe TE-99. The original purpose of reactor R-2 was to enable us to
further process coal slurries reacted in reactor R-l. Since the reactor
rates experienced 1n R-l were much higher than expected, R-2 was never
used as a secondary slurry reactor. It was only used to prepare feed
32
-------
leach solutions. The leach solutions were prepared by sequentially adding
under agitation sulfurlc add and ferric sulfate to distilled water pre-
viously charged to R-2. After the ferric sulfate dissolved, the leach
solution was transferred to a leach solution storage tank T-7 or T-8.
Inspection of the secondary reactor R-2 consisted of opening the 18-
Inch diameter manway and visually Inspecting the Inside surfaces. It 1s
1n excellent condition. A view Inside R-2 through the manway Is shown 1n
Figure 50.
4.4.8 Filtration and Leach Solution Recovery System
Processed slurries are discharged from the pressurized reactor R-l
Into the flash drum T-5 which operates at atmospheric pressure. A porous
demlster pad 1s situated Immediately above the slurry Inlet. Even so, the
flashed steam and gases from T-5 are vented through the vent gas scrubber
T-4. The underflow slurry 1s gravity fed from T-5 to the filter S-l for
leach solution recovery and coal washing. The slurry level 1n T-5 1s
monitored by a level switch LSH-88 which triggers an alarm 1f the level
becomes too high.
S-l Is a belt filter equipped with two filtration zones each having a
discrete filtrate collector system. The filter belt consists of a poly-
propylene mesh cloth outer belt supported by a channeled rubber Inner belt.
Feed slurry, typically at 213°F, from T-5 1s distributed on the belt by
a stationary spreader. The leach solution 1s removed from the coal In the
first filtration zone, collected 1n a filtrate receiver V-2, and recycled
through pump P-9 to either storage tank T-7 or T-8. After this Initial
filtration, the filter cake 1s steamed and sprayed with hot water from
overhead nozzles. The filtrate from cake wash 1s removed from filter cake
1n the second filtration zone. This filtrate 1s collected 1n the wash water
receiver V-3 and transferred by pump P-10 to the waste disposal tank T-9.
The filter cake 1s discharged from S-l through a chute, a water spray 1s
used to remove remaining coal particles from the outer belt. This prevents
blinding of the belt. The belt wash 1s collected 1n a tray under the
filter which drains to the filter wash pump T-8. The pump discharges the
33
-------
belt wash effluent to either the cake wash section of the filter or to the
waste disposal tank T-9. The filtration unit 1s completely enclosed 1n a
reinforced fiberglass hood. Sampling ports built Into the hood permit
sampling processed coal before and after the wash operation.
Inspection of the flash drum T-5 consisted of removal of the level
switch LSH-88 from the bottom of the tank. The switch probe and the
Internal parts of T-5 visible through the open port are in very good
condition.
During RTU operation, the Inner rubber belt failed. The belt had
softened due to prolonged exposure to the hot leach solution and began to
adhere to the lip of the vacuum pans. The belt was literally pulled apart.
The belt was repaired, and the vacuum pan edges were fitted with teflon
overlays to preclude adherence at the belt-vacuum pan Interfaces. The
filter operated properly for the duration of operation.
The latest inspection shows that the Inner and outer belts are Intact
and have not deteriorated since RTU shutdown. The cloth outer belt 1s worn
from use and should be replaced when RTU operation is resumed.
All of the fiberglass components show no effects of weathering.
However, some of the rubber seals and the belt dams are beginning to crack.
Some of the metal shafts are also beginning to rust slightly. Electrical
power to the belt drive was turned on. No problems were encountered.
The filtrate pump P-9 was removed and disassembled for Inspection.
A light reddish brown residue was found on Internal surfaces. Wire brush-
ing these surfaces did not reveal any evidence of corrosion. The pump
seals are slightly worn, but are otherwise in good condition.
The same reddish brown residue was also found 1n the process line
AA-8 leading from the filtrate receiver V-2 to the filtrate pump P-9.
The pipe and flanges are 1n good condition; no sign of any corrosion.
34
-------
Since RTU shutdown, the vacuum pump K-l has been turned on regularly
to prevent the seals from freezing to the shafts. Conversations with the
manufacturer resulted 1n their recommendation not to disassemble the pump.
They feel that the operating history 1s too short to justify any disassembly
at this time. Their recommendation was honored.
The belt ash pump P-8 was disassembled and Inspected. No corrosion
or abrasion was found.
4.4.9 Gasket Sealing Surfaces
The defect found most frequently during the Inspection was crevice
corrosion of gasket sealing surfaces such as flange faces and valve seal
retainers. Even so, only 30% of those surfaces inspected showed any
evidence of corrosion. The severity of most of those was very slight. It
was only those sealing surfaces exposed to high processing temperatures
and high oxygen concentrations that were corroded severely enough to be of
concern.
Apparently an electrolytic corrosion cell is initiated by leach
solution seeping under the gasket material. The driving force 1s probably
the oxygen concentration gradient between the solution under the gasket
(low concentration) and the bulk of the solution in the immediate vicinity
(high concentration). With this mechanism, the severity of the corrosion
would be expected to Increase with Increased dissolved oxygen concentra-
tion and with Increased temperature. This was indeed the pattern observed
during the inspection. However, the temperature seems to have a greater
effect than the dissolved oxygen concentration.
Figures 51 through 58 show the very slight crevice corrosion found on
flange faces in process lines containing cold leach solution. Likewise,
Figure 59 shows the very slight crevice corrosion found on the seal
retainers 1n valve T4-6 taken from the filter cake wash line from filter
S-l to waste tank T-9. The concentration of dissolved oxygen in the leach
solution located in these process lines 1s very low.
35
-------
Figures 60 through 62 show the very slight crevice corrosion found
on flange faces from the foam knockdown drum V-l. The leach solution 1n
V-l 1s at room temperature, but 1s also nearly saturated with oxygen from
the vent gas from reactor R-l. Figures 63 and 64 also show the presence
of very slight crevice corrosion on mating flanges at the V-l gas discharge
port. This represents the only Incidence of corrosion found 1n vapor space
portions of the RTU. However, leach solution probably reached this area
when V-l was Inadvertently flooded during one of the early experimental
runs. The flange had not been disassembled prior to this Inspection.
Figures 65 and 66 show the crevice corrosion evident on mating flanges
at the outlet of the E-2 heat exchanger. The leach solution from V-l is
heated to approximately 170°F by this heat exchanger. Again, the severity
1s very slight.
It Is in T-2 that the effect of temperature on the crevice corrosion
be seen. The temperature 1n the first of the three cells 1n T-2 is typi-
cally 180°F. The temperature in cells 2 and 3 1s 205°F and 215°F, respec-
tively. Figure 67 is a close-up picture of the crevice corrosion found on
the manway cover, which 1s on cell 2. The corrosion 1s still slight, but
noticeably deeper than that observed in cooler sections. Figures 68 and
69 show slightly more extensive corrosion found on the mating flanges for
the cell 3 thermocouple probe. Similar degree of crevice corrosion on the
outlet flanges of pumps P-l and P-7 are shown in Figures 70 and 71. Both
of these pumps have been used to transfer hot slurry from the mix tank T-2
to reactor R-l. Figure 72 shows the slight crevice corrosion on a flange
face taken from the slurry feed line leading from pump P-l to cell 3 of
the reactor R-l.
The most extreme operating conditions anywhere 1n the RTU are 1n
reactor R-l. The slurry is at the highest temperature 230°F to 275°F,
and saturated with oxygen at the operating pressure, 50 to 100 psi. As a
result, the crevice corrosion 1s the most severe 1n the reactory system.
An extreme example of crevice corrosion experienced under these conditions
1s shown in Figure 73. This picture shows the Inside of the manway cover
located on cell 3 of reactor R-l. The manway cover had been used to test
36
-------
an elastomer material as a potential tank Uner. During RTU operation,
the adhesive failed between the upper portion of the Uner and the manway
cover creating a crevice between the two. Figures 74 through 79 show
the moderate crevice corrosion found on flange faces at the R-1 discharge
valve assembly. This assembly was comprised of two remote actuated bell
valves. One of these valves, LV-59, was normally open during RTU operation
and only closed when the low level sensor In R-1 Indicated that the slurry
level in cell 5 was too low. The second valve, KV-241, was opened or
closed by a timer to meter the flow of slurry out of the reactor.
Figures 80 through 83 show the crevice corrosion found on the flange
faces and valve seal retainers located in other parts of the reactor system,
The degree of corrosion 1s less than that experienced on the discharge
valve assembly. However, the discharge valve assembly was installed during
RTU construction. The equipment shown 1n the figures were Installed 1n
December 1977.
Except for those sealing surfaces located in the reactor system, the
observed crevice corrosion does not present a concern regarding the near
term operation of the RTU. Operation could continue for some time before
leach solution leakage would occur. Even then, the defect would probably
manifest itself as a slow seepage of leach solution.
However, the location and frequency of the observed crevice corrosion
suggests that seepage of leach solution under the gasket must occur to
Initiate the defect. The obvious preventatlve Is to utilize a better
gasket seal. Two types of gaskets have been used to date: thin garlock
and thicker polymeric material (EPDM). Neither 1s completely effective.
It 1s recommended that a non-curing adhesive type material be tried be-
tween the gasket and the metal sealing surface. Both surfaces can be
completely wetted with this adhesive thus preventing the Initial seepage
of leach solution Into the Interface. The EPDM gaskets also developed
circumferential cracks Inside and under the Inside diameter of the sealing
surface. Examples are shown 1n Figures 84 through 87. The pattern of the
cracks suggest that the EPDM has deteriorated and that the flange bolts
may have been over-tightened. The only other gasket found cracked 1s
37
-------
shown in Figure 88. This gasket is from the flange joint on the discharge
part of the filtrate receiver V-2. It is cloth reinforced polymeric
material. Since this gasket was installed by the manufacturers of the
filtrate collection equipment, efforts are underway to Identify the gasket
material.
4.4.10 Equipment Spare Parts
As part of the RTU inspection, spare parts for the major pieces of
equipment were inventoried. In addition to numerous valve and rr.ichanical
seal kits, the inventory consists of:
1 Cloth filter belt, P/N GB3725KVK, for S-l filter
1 Inner belt for S-l filter
1 Leach solution feed pump P-13 consisting of one each:
e Moyano pump frame 3MA, Form FA, S/N AS-67166
o Carter vari-speed reduction gear, Series 1DNRS
e Reliance motor, P/N P14G2402S-XC, 1-1/2 HP
o Foxboro speed control, Type C, S/N 3386296
1 Duplex strainer (SP-11), 2", stainless steel
2 Fischer-Porter magnetic flow meters, Mod 10D1418A, 50 GPM max
2 Signal converters, PR-50, for magnetic flow meters
1 Pump rotor for P-l, 316SS
1 Billet for pump rotor, Hastelloy C
2 ITT Barton flow meters, turbine type
38
-------
10
Figure 4. RTU Control Console,
-------
£
I
01
40
-------
Figure 6. Coal Bin Tilter and Oxygen Analyzer.
-------
Figure 7. Coal Bin Tilter.
42
-------
Figure 8. Equipment on Level 4 of RTU
-------
l-igure v> Vent Gas Scrubber T-4 and Knockout Drum I/-I.
-------
Figure 10. Coal Feed Tanks T-l and T-6 and Weigh Belt Feeder A-3.
-------
rigure 11 Slurry Mix Tank T-2.
46
-------
Figure 12. Primary Reactor R-l.
-------
Figure H. Slurry Mix Tank T-2 and Primary Reactor /?-/.
-------
Figure 14. Belt Filter.
49
-------
Figure 15. Filtrate Collection Equipment.
-------
Figure 16. Recirculation Pumps for Reactor R-l
-------
iiuii
ill!!!
II
•It
Figure 17. (.each Solution Storage Tanks and Pumps,
-------
Figure 18. Rubber Boot Between Coal Storage Tank T-l and Live Bottom Feeder A-2.
-------
•
Figure 19. Rotory Vane from Coal Feed Valve A-4.
-------
Ul
-------
en
cn
Figure 21. Rotor from Leach Solution Feed Pump P-13.
-------
Figure 22. Shaft Pins from Leach Solution Feed Pump P-13.
-------
Figure 23. Bubble Cap Tray Inside Knockdown Drum V-l.
58
-------
to
Figure 24. Weir Between Cells 1 and 2 of Mix Tank T-2.
-------
Figure 25. Weir Between Cells 2 and 3 of Mix Tank J-2.
-------
Figure 26. Agitator Blade from Cell 2 of Mix Tank T-2,
61
-------
ro
Figure 27. Thermocouple Probe TE-21 from Cell 3 of Mix Tank T-2.
-------
(feS A
•\
D '
-
Figure 28. Thermocouple Well Flange 1n Cell 3 of Mix Tank T-2.
-------
Figure 29. Rotor from Slurry Feed Pump R-1,
-------
Figure 30. Rotor End from Slurry Feed Pump P-7.
-------
Figure 31. Rotor Center from Slurry Feed Pump P-7,
-------
^7 PU'VP
*i*tSjf=T> /<*&•
Figure 3^. Intermediate Drive Shaft from Slurry Feed Pump P-7.
-------
Figure 33. Universal Linkage Shaft from Slurry Feed Pump P-7.
-------
t fT&SSAX" -
Figure 34. Shaft Pins from Slurry Feed Pump P-7.
-------
figure 35. Retafnfng Rfng from Slurry Feed Pump P-7.
-------
Figure 36. Pipe Flange Which Mates with Slurry Feed Pump P-l Discharge Port,
-------
Figure 37. Weir and Vessel Wall Inside Cell 3 of Primary Reactor R-l.
-------
Figure 39. Flange from Recirculatlon Loop for Cell 4 of Primary Reactor R-l,
-------
Figure 39. Valve Body from Recirculation Loop for Cell 4 of Primary Reactor R-1
-------
40. Thermocouple Probe from Cell 5 of Primary Reactor R-l
-------
-
Figure 41. Inlet to Recirculation Pump P-5.
-------
Figure 42. Outlet of Redrculation Pump P-5.
-------
Figure 43. Pump Housing from RecircuJatfon Pump P-5
-------
Figure 44. Impeller Back Plate from Recirculation Pump P-5 - Side View.
-------
Figure 45. Impeller Back Plate from Redrculation Pump P-5 - End View.
-------
Figure 46. Impeller from Redrculatfon Pump P-5. Front View.
-------
-
•V: •
Figure 47. Impeller from Rectrculatlon Pump P-5 - Back View.
-------
Figure 48. Drive Shaft from Reclrculatlon Pump P-5.
-------
Figure 49. float We)] for Level Monitor Gauge LT-58 from Cell 5 of Primary
Reactor R-l.
-------
Figure 50. Interior View of Secondary Reactor R-l.
-------
CO
Figure 51. Inlet Flange Face of Leach Solution Circulation Pump P-12.
-------
00
Figure 52. Outlet Flange Face on Leach Solution Circulation Pump P-12
-------
Figure 53. Flange Face 1n Inlet Isolation Valve T4-28 to Tank T-9.
-------
oo
VO
Figure 54. Flange Face on Reactor R-2 Manway.
-------
ID
O
Figure 55. Flange Face on Inlet Spool to Leach Solution Pump P-13.
-------
Figure 56. Flange Face from Leach Solution Feed Line to Foam Scrubber T-3.
-------
' -
••
Ffgure 57. Flange Face from Leach Solution Feed Line to Pump P-13,
-------
Figure 58. Flange Face on Basket Strainer SP-11 Outlet Port.
-------
Figure 59. Disassemble Valve T4-6 from Filter Cake Wash Line to Tank T-9.
-------
«
Figure 60. Level Switch LSL-37 from Knockout Drum V-l
-------
Figure 61. Lower Flange Face on Level Controller LC-39 for
Knockout Drum V-l.
96
-------
Figure 62. Lower Flange Face on Knockout Drum V-l.
-------
Ffgure 63. Thermocouple Probe TE-148 from Knockout Drum V-I.
-------
Figure 64. Mating Flange to Thermocouple Probe TE-148.
-------
o
o
Figure 65. Flange Face at Outlet of Heat Exchanger E-2.
-------
-------
Figure 67. Flange Face on Manway Port on Cell 2 of Mix Tank T-2,
102
-------
—I
o
to
Figure 68. Thermocouple Probe TE-21 from Cell 3 of Mix Tank T-2.
-------
*•" '"
n
-------
Figure 70. Flange Face on Outlet of Slurry Feed Pump P-l
-------
Figure 71. Flange Face on Outlet of Slurry Feed Pump P-7.
-------
Figure 72. Flange Face from Slurry Feed Line to
5 of Primary Reactor R-l.
107
-------
Figure 73. Manway Cover to C«ll 3 of Primary Reactor R-l
-------
Figure 74. Face of Flange Mating with Low Level Control Valve LV-59.
-------
Figure 75. Flange Face on Inltt of Low Level Control Valve LV-59.
-------
Figure 76. Flange Face on Outlet of Low Level Control Valve LV-59
-------
rsj
Figure 77. Flange Face on Spool Separating Low Level Control Valve LV-59
and L*v«l Control Valve KV-241.
-------
Figure 78. Flange Face on Inlet of Level Control Valve KV-241.
-------
-
Figure 79. Flange Face on Outlet of Level Control Valve KV-241.
-------
Figure 80. Flange Face on Reactor R-l Cell 4 Discharge Line to Disposal Tank T-9.
-------
Figure 81. Hange Face on Valv« R4-52 1n Cell 4 Redrculatton Loop for Reactor R-l.
-------
Figure 82. Seal Retainer Rings and Ball for Valve R4-50 from Cell 4
Redrculatlon Loop for Reactor R-1.
-------
Figure 83. Thermocouple Probe TE-56 from Cell 5 of Reactor R-l.
-------
figure 84. Flange Gasketsfron Heat Exchanger E-2.
-------
Figure 85. Flange Gaskets from Low Level Control Valve LV-59.
-------
Figure 86. Flange Gasket from Reactor R-1 Cell 4 Sample Valve R4-76.
-------
Figure 87. Hange Gaskets from Steam Inlet Line to Cell 1 of Reactor R-1
-------
oo
Figure 88. Flange Gasket from Filtrate Receiver V-2 Discharge Line,
-------
5.0 BENCH-SCALE EXTRACTIONS (TASK 2A)
A variety of coals were Investigated for application of the Gravichem
Process. The coals included two coals supplied by Tennessee Valley
Authority (TVA) and five gob-pile coals. Each coal was separated by float-
sink techniques in iron sulfate leach solution and/or conventional organic
solvent at various top sizes. The resulting fractions were analyzed for
sulfur forms, ash content and heat content after washing with water and
drying. In selected cases the sink fraction, which contains most of the
pyrite, was reached In leach solution according to Meyers Process conditions
to chemically remove the pyrite. The sink fractions were analyzed for
sulfur forms and heat and ash content.
5.1 TVA COAL STUDIES (TASK 2A1)
Kentucky No. 9 seam coal was supplied by the Tennessee Valley Authority
for bench-scale extractions. Experimental Investigations on the ROM and
3/8 x 0 coal were completed with respect to the float-sink separation of
the coals 1n 1.3 specific gravity Iron sulfate leach solution or organic
liquid. Both float and sink fractions were analyzed for sulfur forms, ash
content and heat content after washing with water and drying.
5.1.1 Float Sink (Organic Liquid) (Task 2A1a)
As-received run-of-mine (ROM) TVA coal of greater than 2 Inch top
size gave a B7% yield of float coal and a 33% yield of sink when gravity
separated in 1.3 specific gravity organic liquid (Table 5). Gravity
separation was accomplished at 20°C in a 1:4 coal and organic liquid
slurry. The slurry was mixed thoroughly by careful agitation and then
allowed to separate 1n a quiescent state. The resultant float product
was carefully skimmed off of the solution and the sink subsequently re-
covered by filtration.
124
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TABLE 5. SETTLING TANK FLOAT/SINK SEPARATION/ANALYSES OF TVA (AS RECEIVED) COAL
PO
tn
Separation
Medium Fraction
@ 20eC
Yield Ash
% %, w/w
Whole Coal - 17
Organic*
Liquid
(1.3 S.G
Float
Sink
Leach** Float
Solution Sink
(1.3 S.G.)
(Reacted
*M1xture
Aqueous
Sink)***
of toluene and
ferric sulfate
Fe*** as
Fe2(S04)3
(wt X)
67 7
33 36
43 4
57 25
18
perch! oroethyl ene ,
(ferrl-floc) with
H2S04
(wt X)
.84
.17
.82
.70
.54
.98
wt ratio
specific
Heat
LOnteritf • • •
Btu Total
11577 3.84
13423 2.56
8590 6.05
13833 2.36
10377 4.19
11486 3.35
1:1.35.
gravity obtained as
H20 and S04* as
Fe2(S04)3
(wt %)
Sulfur Content, X w/w Lbs S02
Pyrlte Sulfate Organic MM/Btu
2.80 0.44 *0.61 6.63
1.00 0.06 1.50 3.81
4.33 0.77 0.95 14.09
OJ1 0.01 1.64 3.41
3.41 0.50 0.28 8.08
1.48 0.41 1.46 5.83
follows:
7.5
4.0
88.5
***
Reacted for 48 hours 9 102°C In aqueous ferric sulfate (ferrl-floc) above**.
-------
5.1.2 Float-Sink (Leach Solution) (Task 2A1b)
ROM Kentucky No. 9 coal greater than 2 inch top-size gravity separated
at 20°C in 1.3 specific gravity Meyers Process leach solution
(7.5% Fe, 4% H2S04). A 1:4 coal and leach solution slurry was mixed
thoroughly by careful agitation and then allowed to gravity separate in a
quiescent state. The resultant float product was carefully skimmed off
of the solution and the sink subsequently recovered by filtration. The
product coals (float and sink) were washed and dried and the yields deter-
mined, i.e., 43% float and 57% sink (Table 5). This compares favorably
with the yield obtained using 3/8" x 0 top-size Tennessee Valley Authority
coal (40% float, 60% sink) reported in Section 2Ald.
5.1.3 Meyers Process on ROM Coal (Sink) (Task 2Alc)
The sink fraction of the ROM Kentucky No. 9 coal from the 1.3 specific
gravity Meyers Process leach solution (Scope-Section 2Alb) was treated by the
Meyers Process for 48 hours at 102°C. It is seen in Table 5 that a
significant reduction in ash and pyritic sulfur was attained, however, the
product sink coal does not meet the "4-1b" state standard after processing
for the stated 48-hour period.
5.1.4 Float-Sink 3/8" x 0 Coal (Task 2A1d)
ROM Kentucky No. 9 seam coal supplied by the Tennessee Valley Authority
was subjected to float-sink separation in 1.3 specific gravity iron sulfate
leach solution or organic liquid at 3/8" x 0 top-size. Both float and sink
fractions were analyzed for particle size distribution, sulfur forms, ash
content and heat content after washing with water and drying. Analyses are
presented in Tables 6 and 7.
The particle size distribution data (Table 6) shows that there is no
significant particle size segregation in either leach solution or organic
solvent float-sink techniques. The analytical data in Table 7 shows that
organic solvent and leach solution gravity separation give near identical
products and that the Gravichem Process will give a 40/60 float ys_ sink
product yield.
126
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TABLE 6. PARTICLE SIZE OF FLOAT AND SINK FRACTIONS
OF TVA COAL
Screen Size
3/8 inch
1/4 inch
4 mesh
8 mesh
14 mesh
48 mesh
Pan
TOTAL
Organic
Float Fraction
2.6
26.7
16.9
23.4
13.5
12.6
4.3
100.0
% Retained
Leach
Float Fraction
1.5
22.0
17.6
24.6
14.8
15.0
4.5
100.0
Organic
Sink Fraction
2.2
22.6
14.4
19.7
12.2
15.3
13.6
100.0
The Tennessee Valley Authority sink coal from the leach solution
separation was size-reduced and treated by the Meyers Process to the 90%
pyrlte removal level (Table 8). The recovered sink fraction resulting
from the Gravichem Process (Figure 89) was crushed by blending a 1:3 coal
and leach solution (7.5% w/w Fe and 4% HgSO^; specific gravity 1.3) slurry
in a one-gallon stainless steel laboratory blender for 10 minutes at
^ 15,000 rpm. A temperature rise from 20°C to 70°C was noted in the re-
sultant blend during the stated residence time. The remaining slurry was
filtered and the coal cake retained for further processing.
Particle size analysis of a representative sample of the coal cake
was performed and it is seen in Figure 90 that significant size reduction
1s attained for the sink fraction ground 1n the leach solution.
A series of extractions was performed on the ground sink fraction at
102°C (atmospheric pressure) with a 1.3 specific gravity solution contain-
ing 7.5% w/w Fe and 4% HpSO*. Processing was accomplished at intervals
up to 48 hours. Data from this experimentation are presented in Table 8.
127
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TABLE 7. FLOAT/SINK SEPARATION/ANALYSES OF TVA COAL
ro
oo
Separation
Medium
@ 20°C
--
*
Organic
Liquid
(1.3 S.G.)
**
Leach
Solution
(1.3 S.G.)
*
Mixture
**
Aqueous
Fraction
Whole Coal
Float
Sink
Float
Sink
of toluene and
ferric sulfate
Fe as
Fe2(S04)3
(wt X)
* 7.5
Yield
--
39
61
40
60
Ash Heat Sulfur Content, % w/w
%w/w fnntpnt
Btu Total Pyrite Sulfate Organic
19.14 11675 3.78 2.08 0.11 1.59
4.90 13851 2.37 0.56 0.05 1.76
29.6 9868 4.76 3.16 0.23 1.37
3.97 13923 2.30 0.59 0.01 1.70
26.96 10731 4.94 3.19 0.35 1.40
Ibs S02
MM Btu
6.48
3.42
9.65
3.30
9.21
perchloroethylene, wt ratio 1:1.35
(Ferri-floc)
H2S04
(wt X)
-v 4.0
with specific gravity obtained as follows:
H20 and S04~ as
Fe2(S04)3
(wt X)
«, 88.5
-------
TABLE 8. RATE DATA ON PROCESSING 1.3 S.6. TVA COAL SINK FRACTION WITH 7.5% IRON SOLUTION
(4% H2S04) AT 102°C AND ATMOSPHERIC PRESSURE
ro
Exper. Process Time Ash
No. Mrs. % w/w
Starting
Coal (1 .3 sink)
Leach Solution
Organic Liquid
1 2
2 4
3 8
4 14
5 48
rfhole Coal
26.96
29.58
22.33
20.80
19.97
18.89
17.42
19.14
Heat Content
Btu/lb
10731
9875
11188
11424
11540
12038
11544
11675
Sulfur Content, % w/w
Total
4.94
4.76
3.48
2.97
2.69
2.32
2.32
3.78
Pyrite
3.19
3.17
1.85
1.38
0.93
0.57
0.33
2.08
Sulfate
0.35
0.23
0.37
0.20
0.28
0.28
0.36
0.11
Organic
1.40
1.37
1.26
1.38
1.47
1.48
1.63
1.59
Us S02
MM Btu
9.21
9.64
6.22
5.20
4.66
3.85
4.02
6.48
(Prior to
gravity separation)
-------
3/8 INCH X 0 LEACH
COAL SOLUTION
MIX
TANK
CO
o
FLOAT
^
GRA
SEP
TAN
•-FILTERED, WASHED
I 3/8" X 0 SINK PRODUCT
AGITATOR
TANK
(IN-SITU
GRINDING)
3/8" X 0 FLOAT PRODUCT
MEYERS PROCESS
28 MESH X 0
PROCESSED SINK PRODUCT
Figure 89. Gravlchem Processing of TVA Coal
-------
AS RECEIVED
irr-
O GROUND IN
LEACH SOLUTION
i
"60~
% RETAINED
Figure 90. Size Distribution by Sieve Analysis of TVA Sink Coal.
131
-------
Data presented in Table 8 indicate that ambient pressure Meyers pro-
cessing of ROM Kentucky No. 9 1.3 specific gravity sink coal can effect
at least 90% pyritic sulfur (S ) removal in 48 hours resulting in a product
coal which meets the Tennessee State Standard requirements of 4 Ibs
S02/105 Btu. Considering the high ash (27.0) and sulfur (4.9%) of the sink
starting coal, this represents a significant improvement in coal quality;
i.e., 9.2 Ibs S02/106 Btu reduced to 4.0 Ibs S02/106 Btu.
The rate of pyritic sulfur reduction in the above series was determined
(1 2)
using the standard approach presented in earlier studies ' . Basically,
the rate constant K. is obtained from the relation:
U u o
KL = "P , P (1)
where
t - Is the time required to reduce coal pyrite to W , in hours
W° - Is the pyrite concentration of the starting coal , in wt %
W - Is the pyrite concentration of the coal at time t, in wt %
Y - Is the average ferric ion-to-total iron ratio during reaction,
dimensionless
In the case of 50% pyrite removal this express reduces to:
w; tv
Figure 91 represents a plot of the decrease in S (W = 1.88 S ) as
O
a function of reaction time at 102 C. The rate constant, K. , for the
-1 -1
reaction was determined to be 0.08 W hr for using the relation in
r i
Equation (2) above. Earlier studies on a TVA furnished coal revealed
a rate constant, K., equal to 0.14 W" hr" for a lower ash (15.5%) start
ing 1.3 specific gravity sink coal.
132
-------
CO
t*>
n>
10
co -o
-<•«<
3 -J
X" -*•
rt
O -*•
O O
01
—• CO
O C
r>o -j
O
o i—
fD
n
to
-s «-••
n> o>
CO
v> -«.
c -?
-s o
fD 3
co
to
•
(7)
PROCESS TIME, MRS
-------
5.2 GOB PILE COALS (TASK 2A2)
Gob pile samples representing five coal piles were obtained from
Banner Industries and Peabody Coal Company. Each of these coals were
subjected to float-sink techniques In Iron sulfate leach solution and/or
conventional organic solvent at various top-sizes. It should be noted
that the coal samples were mainly the fine refuse of physical coal-cleaning
processing. Only one gob pile (Peabody No. 2) could be gravity separated
and/or processed at the 3/8" x 0 particle size, in addition to the as-
received size, since the remaining four coal samples were
-------
TABLE 10. GRAVI-SEPARATION OF BANNER GOB COAL
Coal
Jim Role Raw
J1tn Role Float*
J1m Role Sink*
Enoco Raw
Enoco Float**
Enoco Sink**
% Wt
100
46
54
100
32
68
X Ash
33.79
8.68
58.25
24.88
3.25
28.48
I
Total
3.22
2.33
2.43
3.23
2.23
1.30
Dry Basis
Sulfur
Sulfate
0.75
0.88
0.21
2.00
0.06
0.28
Btu
9171
12922
5352
9556
13630
9642
Ibs S02
106 Btu
7.02
3.61 ) 6 56
9.08 f Wt" Ave'
6.76
3.27 | 2 88
2.70 1 Wt< Ave-
Separated In 1.37 sp. gr. Iron sulfate solution, roughly 1/8" x 0.
»
Separated 1n 1.33 sp. gr. Iron sulfate solution, roughly 1/8" x 0.
-------
Extensive laboratory work was accomplished on the remaining three
gob piles as per the statement of work with the exception that float/sink,
etc. was only accomplished on 3/8" x 0 Peabody No. 2 coal as noted above.
5.2.2. Float-Sink Analysis (Task 2A2)
Plymouth, Peabody No. 1 and Peabody No. 2 gob coals were gravity
separated as described earlier in 1.3 specific gravity iron sulfate leach
solution and organic liquid. Table 11 presents the coal analyses of whole
coal as well as float-sink fractions of Peabody No. 1 and Plymouth gob
pile coals. It is seen that the Plymouth coal is substantially a "clean"
coal when compared to the Peabody No. 1 coal. Essentially no difference
in total sulfur is noted in the float and sink fractions of the Plymouth
coal, although the distribution of sulfur forms is characterized by a
higher organic and lower pyritic sulfur in the float fraction as expected.
Peabody No. 1 coal quality is greatly enhanced as a result on gravity
separation in Meyers Process leach solution. Particularly noted is the low
ash yield obtained with leach solution float fraction (6.2%) as compared
to the organic liquid separation (11.8). Likewise a coal product
(3.93 Ibs S02/10 Btu) is also obtained which meets the Kentucky state
standards for allowable S02 stack gas emissions (4.0 Ibs SCyiO6 Btu).
Gravity separation of Peabody No. 2 coal (as received, + 1 Inch) was
likewise accomplished in 1.3 specific gravity iron sulfate leach solution
and organic liquid. Table 12 presents the coal analyses of the float/sink
fractions.
Gravity separation (Series 1) produced substantially lower yields
for the float fractions when compared to previous (Table 7) gravity
separations of Peabody coal at ^ 14 mesh top-size. This is not unexpected
since standard gravity separation techniques used at the mine should be
more effective in removing "clean" coal at large particle size.
Following the above separation a portion of the sink material was
ize-reduced to 3/8 Inch top-size and subjected to float/sink procedures
136
-------
TABLE 11. SETTLING TANK FLOAT/SINK SEPARATION/ANALYSES OF GOB PILE COALS (14 MESH)
Separation
Gob Pile Medium Fraction
@ 20"C
Pea body
Plymouth
*M1xture
**
Aqueous
- —
--
Organic*
Liquid
(1.3 S.G.)
Leach**
Solution
(1.3 S.G.)
__
--
Organic*
Liquid
(1.3 S.G.)
Leach**
Solution
(1.3 S.G.}
of toluene and
ferric sulfate
Fe^as
Fe2(S04)3
(wt X)
•v- 7.5
Whole Coal
Whole Coal
Float
Sink
Float
Sink
Whole Coal
Whole Coal
Float
Sink
Float
Sink
perchloroethylene
(ferrl-floc) with
H2S04
(wt *}
•v, 4.0
Yield
1
_ m
--
20
80
29
71
__
--
39
61
49
51
, wt ratio
specific
Ash
%, w/w
39.6
39.2
11.8
49.9
6.2
52.4
13.6
14.6
4.9
20.5
4.5
21.7
1:1.35.
Heat
Conter
Btu
8387
8413
12478
6B14
13419
6254
12495
12815
14229
11902
14465
11790
gravity obtained as
H20 and S04B
Fe2(S04)3
*, 88.5
as
j£
Total
3.94
3.99
2.76
4.15
2.63
4.99
0.86
0.89
0.85
0.91
0.92
0.8B
fol 1 ows :
Sulfur Content, % w/w
Pyrlte
2.30
2.56
0.99
3.41
0.80
3.45
0.21
0.24
0.13
0.31
0.10
0.30
Sulfate
0.01
0.01
0.02
0.07
0.02
0.77
0.01
0.00
0.01
0.01
0.01
0.02
Organic
1.63
1.42
1.75
0.67
1.81
0.77
0.65
0.64
0.71
0.59
0.81
0.56
Ibs S02
KM Btu
9.39
9.49
4.42
12.18
3.93
15.96
1.38
1.39
1.19
1.53
1.27
1.49
-------
TABLE 12. SETTLING TANK FLOAT/SINK SEPARATION/ANALYSES OF GOB PILE COALS PEABODY
#2 COAL (AS-RECEIVED)
CO
oo
Series
1
(As Received)
2
(Ground to
3/8" top-size)
Separation
Medi urn
@ 20°C
Organic*
Liquid
(1.3 S.G.)
Leach**
Solution
(1.3 S.G.)
--
Organic*
Liquid
(1.3 S.G.)
Leach**
Solution
(1.3 S.G.)
Fraction
Float
Sink
Float
Sink
Starting Coal
Float
Sink
Float
Sink
*
Mixture of toluene and perchloroethylene,
**
Aqueous ferric
fe*** as
Fe2(S04)
(wt X)
sulfate (ferri-floc) with
3
H2S04
(wt X)
Yield As
% X.
8 10
92 76
6
94 83
*** 83
10 6
90 84
Heat Sulfur Content, % w/w . . Qn
hrnntnn4. IDS iU,
w/w Btu Total Pyrite Sulfate
.73 12643 2.92 1.23 0.02
.16 2623 5.70 5.18 0.02
.50 1002 5.55 5.04 0.29
.50 1002 5.55 5.04 0-29
.23 14071 2.98 1.05 0.01
.77 1272 5.39 5.20 0.03
9 9.19 13001 4.11 2.25 0.02
91 85.19 1222 6.26 4.73 0.36
wt ratio 1 :1 .35.
specific gravity
H20 and S04~
Fe2(S04)3
(wt X)
obtained as follows:
as
Organic MM Btu
1.67 4.6
0.51 43.5
0.22 110
0.22 110
1.92 4.24
0.16 84.8
1.85 6.3
1.18 1 02
7.5
4.0
88.5
Sink portion (above) ground to 3/8" top-size.
-------
again. It is seen in Table 12 (Series 2) that additional float coal 1s
released providing an effective 15% cumulative float recovery from the
Peabody No. 2 coal. Thus size reduction to 3/8 inch top-size does increase
the yield. However, the 15% cumulative float is still less than the 29%
yield observed for 14 mesh Peabody No. 1 coal in Table 11. Further reduction
of the sink fraction to -28 mesh did not materially provide additional
float product.
5.2.3 Meyers Processing (Task 2A2)
Meyers Process desulfurization was performed on four sink product
coals from the foregoing gob coal gravity separations in Iron sulfate
leach solution. Forty-eight hour processing, at 102°C, of the sink
fractions obtained from Plymouth, Peabody No. 1 and Peabody No. 2 gravity
separations plus the crushed sink fraction (-28 mesh) from Peabody No. 2
was completed.
Sink coal, obtained from float-sink separation 1n iron sulfate leach
solution of 14 mesh waste coal from Plymouth and Peabody mines, was reacted
(Table 13) under Meyers Process conditions for chemical removal of pyrltlc
sulfur. The two steps of float-sink separation in leach solution and
Meyers Process treatment of the sink fraction constitute the Gravlchem
Process.
The Plymouth sink coal containing 22% ash and 1.5 Ibs S02/106 Btu
before chemical reaction, was reduced to 19% ash and 1.1 Ibs SCL/IO6 Btu
after five hours reaction at 102°C. The pyrltic sulfur content was re-
duced by 63% (0.19% w/w) with no increase 1n sulfate or organic sulfur.
Continuation of the extraction for as long as 48 hours resulted in no
further reduction 1n sulfur content per unit heat content.
The Peabody coal, containing 52% ash and 16 Ibs S0,/106 Btu, was
c t
reduced to 47% ash and 10 Ibs S02/10 Btu after five hours of processing.
The pyrite content was reduced by 50% (1.73% w/w) while there was
essentially no increase in sulfate and a slight increase in organic sulfur.
139
-------
TABLE 13. PROCESSING OF GOB PILES SINK FRACTION* @ 102°C (AMBIENT PRESSURE)
r^=1 Reaction
Coal T. .
Time, hrs
Plymouth Control
Sink Coal
5
24
48
Peabody Control
#1 Sink Coal
5
24
48
Ash
%, w/w
21.7
19.3
18.4
17.7
52.4
46.7
49.3
42.3
Heat
Content
Btu/lfa
11790
12000
12034
12251
6254
7009
6632
7360
Sulfur Content, %, w/w
Total
0.88
0.66
0.66
0.74
4.99
3.46
3.89
3.46
Pyrite
0.30
0.11
0.07
0.07
3.45
1.72
1 .48
0.64
Sulfate
0.02
0.01
0.01
0.01
0.77
0.79
1.12
1.49
Organic
0.56
0.54
0.58
0.66
0.77
0.95
1 .29
1.33
Ibs S02
MM Btu
1.49
1.10
1.10
1.21
15.96
9.84
11 .70
9.40
Sink product from 1.3 S.G. settling tank float/sink in leach solution.
-------
Processing up to 48 hours resulted In an 8U reduction 1n pyritic sulfur
but there was Irreversible sorption of sulfate and an Increase 1n apparent
organic sulfur (probably additional add insoluble sulfate) with no net
reduction in Ibs S02/10 Btu.
It can be concluded that both sink coals contained carbonates and clay
which tended to irreversibly sorb sulfate from the leach solution on pro-
longed (greater than 5 hours) treatment allowing no net decrease 1n sulfur
content per unit heat content. This effect was most pronounced for the
higher ash Peabody sink coal.
Sink coal obtained from float/sink separation of +1 Inch Peabody
No. 2 coal 1n iron sulfate leach solution was reacted at +1 Inch top
size and at -28 mesh. The -28 mesh coal was obtained by reducing the
dried product sink coal (above) to 3/8" top size with subsequent reduction
to -28 mesh as described earlier (Section Z.A.l.d). Table 14 presents the
results of Meyers Process pyritic sulfur removal from both coals (+1 inch
and -28 mesh) after 48 hours at 102°C.
It 1s seen that processing the sink coal achieves no useful purpose
either at +1 Inch top size size or -28 mesh. Sulfate retention is high
as was noted for Peabody No. 1 coal (Table 13). Basically, however, the
high ash content negates useful recovery of this coal.
141
-------
TABLE 14. PROCESSING OF PEABODY #2 SINK FRACTION* @ 102°C (AMBIENT PRESSURE)
Coal
+ 1 inch
Top-Size
-28 Mesh
Time, hrs
Control
sink
coal
48
Control
sink
coal
48
Ach
%, w/w
83.50
81.15
81.79
79.83
Heat
uon ten t 9
Btu/lb
1002
1072
1044
717
Sulfur Content
Total Pyrite
5.55 5.04
7.77 3.60
8.94 5.30
6.30 0.90
, % w/w
Sulfate
0.29
3.67
3.18
5.37
Organic
0.22
0.50
0.46
0.03
Ibs S02
MM Btu
111
145
171
175
Sink product from 1.3 S.6. settling tank float/sink in leach solution.
-------
6.0 SPECIFICATIONS AND ESTIMATES FOR R-l REACTOR REPLACEMENT
The specifications and a drawing for a replacement desulfurlzation
reactor (R-l) constructed of titanium were sent to four vessel fabricators
for price and delivery schedule quotations. The reactor specifications
and drawing are presented 1n Figure92 and Tablesl5 and 16. The following
fabricators were contacted for quotations.
Alloy Specialities, Ltd.
7592 Park Avenue
Garden Grove, CA 92641
(213) 628-6202
Attention: R. H. Higgs
Futura Titanium Corporation
P.O. Box 5004
West Lake Village, California 91359
(213) 873-6912
Attention: Jeff Thomas
Nooter Corporation
P.O. Box 451
St. Louis, Mo 63166
(314) 621-6000
Attention: Gene Smith
Titanium Industries Corporation
17 Industrial Road
Fairfield, New Jersey 07006
(201) 227-5300
Attention: D. Williams
Three of the four fabricators submitted quotes on the reactor. The
price ranges were from $59,000 to $115,000 and delivery schedule from 20
to 28 weeks after receipt of order. Table!? summarizes the bids received.
143
-------
GASKETS
ions
INTERNALS
NO/7115
VtSSEl SUPPT5.
TP.AY1
LINING
HEADS
5H! u
HEM
ASMSTOS COMPOSITION
C.S.
II
11
CARSON STEEL
Tl
Tl
MATE HI AL
SA-36
ASTM
1/16 IN.
•
•
•
•
*
THICK
Of SIGN WrSSUKt INTEINAL 150 PSlGi EXHRNAL 14.7 PSI
AT 300'f.
OltRATING PMSSUHE 110 BIO: TEMHIATUIC 243 -F.
N- 7
M-
N- 6
N- 5
N- 4
N- 3
N- 2
N- 1
N- 0
N-9
N-8
N-7
N-«
N-5
N-4
N-3
N-2
N-l
1
1
4
J
1
5
5
UAUC NO. DEO.
IN
« IN
-1/2 IN
-] "2 IN
IN
IN
-1/2 IN
-1/1 IN
IN
2 IN
1 IN
3 IN
4 IN
2 IN
6 IN
12 IN
2IN
2 IN
SIZE
150 I1
ISO*
RATING
S F
>F
FACING
NOZZLES
PRESS. SW.
MAM .YAY
TH: :\-r-' ( IL
Till I.MC'.. ILL
ST[/-f,' ir-LU
CUTL! T
PU'.'f rrcvciE
Pl/.'f VJC*'ON
S'.'.VU
VAi-OS CUHEI
PRISS. G-GE
LCVH S"':TCM
LEVEL CCNT8OL
PEl:[f VAIAT
«UP;iJRE DISK
MIXER
OIL No. 3 INlfT
CELL No. 1 INLET
SERVICE
TRW
Figure 92. Reactor Drawing.
-------
TABLE 15. DESIGN NOTES
1. Vessel to be constructed according to Unlfered Pressure Vessel Code,
Section VIII, D1v. 1. Code stamp required.
2. Vessel contains coal slurry (Sp.Gr. 1.30). Slurry consists of 20-40%
coal particle (8 mesh top-size) in liquid. Liquid is 4% H2SO.,
3% FeS04, 22% Fe^SO^ in water.
3. Corrosion allowance: Shell 1/16"
Heads 1/16"
Nozzles 1/16"
Internals 1/16" per side
4. X-Ray - Yes. Stress Relief - No.
5. Design loads per Uniform Building Code. Basic wind load - 20 psf.
Design cosmic coeff. - UBC Zone 3.
6. Internals furnished and Installed by vendor.
7. Manhole cover should be hinged.
8. Fireprooflng not required. Insulation by purchaser.
9. Paint C.S. surfaces one shop coal red oxide primer (1-1/2 mil D.F.T.)
Surface preparation - SSPC-SP-2003.
10. Live loading due to mixers
11. Design based on 2:1 S.E. heads. Substitution permitted only if liquid
volume remains unchanged.
12. Internal baffles shall be removable by manway. Detail design by
vendor
145
-------
TABLE 16. FABRICATION NOTES
1. Flange bolt holes shall straddle normal vessel centerlines.
2. Shell and head seams shall equal double welded butt joint where
possible.
3. Nozzles and couplings shall be full penetration welded.
4. Each nozzle and manhole reinforcing pad or segment thereof shall have
a 1/8" NPT test hole located 90° off the vessel centerllne.
5. All tray elevations are to top of tray support ring.
6. Nozzles, manholes and trays shall have same designation as shown on
attached drawing.
7. Fabricator's shop drawings issued for approval shall indicate 1) shell
head, skirt and internals thickness, 2) ASTM numbers for all materials,
3) head and shell sear joint efficiency, 4) name-plate layout,
5) total weight empty (with and without trays) and full of water, and
6) support details.
8. Nameplate shall be stainless steel and preferably located adjacent
to lower manhole. Support brackets shall be used on insulated vessels.
9. Vessel shall be cleaned inside and outside of all dirt, grease scale
and debris.
10. Prior to shipping all openings shall be protected with covers or thread
protectors.
146
-------
TABLE 17. REACTOR BID SUMMARY
R-l Desulfurization Reactor - 38" t x 14'9" T/T, Ti, D.P. 150 psig/-14.7 psig 0 300°F
Fabricator
Price
Delivery Schedule
Remarks
Astro Metallurgical Corp.
(Alloy Specialities)
Futura Titanium Corp.
$ 58,925 FOB
$ 66,000 FOB
20-24 weeks after
receipt of approved
drawings
18-20 weeks after
receipt of approved
drawings
Wall thickness - .3199 in. min
Head thickness - .3172 in. min
Wall thickness - 3/8"
Nooter Corp.
$115,000 FOB 24 weeks after
receipt of order
Wall thickness - 7/16 in.
Head thickness - .38 in. min
-------
7.0 RTU ACETONE EXTRACTION UNIT
This section of the report documents the results of an RTU downstream
processing unit conceptual design study. The effort was aimed at defining
the following: (1) those operations which are required to extract the
elemental sulfur from the RTU processed coal cake; (2) the appropriate
commercially available equipment which can be integrated into a downstream
processing unit (to be referred to henceforth as the Tail-End Unit, TEU);
and (3) an estimated cost to design and construct the envisioned RTU
addition.
Section 7.1 contains a brief discussion of the conceptual TEU,
including such items as a process description, TEU flow diagram, mass
balance, utility requirements equipment design basis, plot plan and
elevation sketch. Section 7.2 presents an equipment list, estimated
equipment costs, and an estimate of total TEU erected plant cost.
7.1 TEU CONCEPTUAL DESIGN
The TEU conceptual design has as its foundation several years of
previously accomplished bench-scale sulfur extraction studies and
accumulated laboratory data^ '. Also significant insight into the design
of the TEU was gained during previously completed conceptual full-scale
Meyers Process and Gravichem Process design activities^ " ' as well as a
prior Meyers Process pilot plant design study^ '.
The background knowledge and information lead to a TEU design which
incorporates RTU generated wet coal cake handling and transport, solvent
contacting sulfur-rich solvent extraction from the coal cake, coke drying
with solvent recovery, solvent purification with sulfur recovery, waste
water neutralization, and solvent storage operations. The integrated
unit, as designed, 1s sized to be compatible with RTU operations in a
148
-------
continuous mode. A flow diagram of the TEU 1s presented as Figure 93.
The diagram presents equipment specifications as well as flow patterns
and Identifying stream numbers. The corresponding mass balance volumetric
flows, and explanatory notes are shown in Table 18. The system steam,
cooling water, process water and electrical requirements are tabulated in
Table 19. A conceptual level TEU pilot plan and front elevation are
shown in Figures 94 and 95 respectively while a perspective sketch of TEU
may be seen as Figure 96.
7.1.1 Process Description
The following paragraphs present a brief discussion of each of the
major subsystems of the TEU.
7.1.1.1 Acetone/Coal Contacting System
Coal which has been processed 1n the RTU and stored 1n tote bins is
fed to the coal feed bin (TX-3) which has a capacity for 10 tons of coal.
The feed bin is blanketed with nitrogen and vented to the vent gas system
to allow for acetone wet coal to be recycled to the contacting system.
The bin discharger (DRX-1) maintains a steady rate of coal up to 500 lb/
hr to the contactor (VX-1). The coal feed bin will hold enough coal for
about a 40 hour run to the contacting system. The contactor (VX-1) 1s a
three stage horizontal vessel with a mixer 1n each stage. The contactor
is sized to provide one hour residence time with a 500 Ib/hr coal rate
and a 1000 Ib/hr acetone rate. The vessel has adjustable weirs to allow
for changes in residence time by adjusting the volume from 1/3 to 2/3 full.
The acetone feed 1s supplied from underground storage tank (TX-1) and pump
PX-1. The feed acetone 1s heated to 133°F 1n exchanger EX-1 and the
contactor slurry 1s maintained at 133°F by a pump-around loop using pump
PX-2 and exchanger EX-2. The coal slurry from the contactor 1s pumped
(PX-3) to the centrifuge (SX-1). The centrifuge 1s sized for 500 Ib/hr
coal and 1100 Ib/hr acetone/water producing a coal cake containing about
15% acetone. The coal cake from the centrifuge can be fed to the drying
system or stored in tote bins for further acetone contacting if necessary.
The centrate from SX-1 1s pumped to the distillation feed storage (TX-2).
149
-------
in
O
T O ••-
ti.m.*tf ^» fc*J -.
M«.»»*» *»». /^~\^
S2Si* ^T--" ' ° JA-i ( )
;«.» J^._»^» * ^Tl
Figure 93. Process Flow Diagram.
-------
TABLE 18. ACETONE EXTRACTION
PRINCIPAL MASS AND VOLUMETRIC FLOWS
1.
2.
3.
4.
5.
6.
7.
a.
9.
10.
11.
Stream Nuaber & Description
Coal to Contactor
Acetone to Contactor
Acetone/Coal Slurry
ex. Contractor
Generate ex. Centrifuge
Coal ex. Centrifuge
Dried Coal ex. Dryer Package
Acetone/Water
ex. Dryer Package
Spent Acetone to Storage
Distillation P»ed (2)
Diatlllatlon Bottoms
Redistilled Acetone (3)
Coal
500
0
500
0
500
500
0
0
0
0
0
Pounds/Hour
Water Acetone
(1)
3J 0
0 1000
33 1000
30 915
3 85
0 0
3 85
33 1000
25 765
25 0
0 765
Total GPM
533
1000 2.5
1533 3.3
945 2.5
588
500
88 0.2
1033 2.6
790 2.0
25 0.1
765 1.9
Density
lb/ft3
81
49
60
49
80
81
49
49
49
62
49
Pressure
psig
0
10
2
2
2
0
2
2
30
30
30
Temp.
°F
70
133
133
133
130
120
70
250
100
(Continued)
-------
TABLE 18. (Continued)
Pounds/Hour
12.
13.
14.
15.
Stream Nuaber & Description
Vapor displaced by filling
Acetone Storage Tank
Acetone recovered from chiller
Vapor to Carbon Adsorber*
Vent Gaa
Nitrogen Water
47.9 Trace
0 Trace
47.9 0
47.9 0
Acetone
47.9
44.5
3.4
Trace
Density
Total GPM lb/ft3
95.
44.
51.
47.
(6) (6)
8 100
5 0.1 49
3 -
9 -
Pressure
PSig
1
1
1
1
Temp.
°F
100
0
0
20
en
r\>
NOTES:
(1) Moisture content on incoming coal will vary from 20Z to 0.22 of the weight of dry coal.
(2) Hater in central* varies from 92 Ib/hr in first extraction to 1 Ib/hr In third extraction.
(3) Distillation Package designed to run at lower feed rates and a higher service factor.
(4) Distillation bottoms will contain 1.5 Ibs. of sulfur per hour.
(5) Maximum instantaneous flow rates in vent system.
(6) Assumes acetone charged to TX-1 at 100 GPM and a 50/50 mixture (by weight) of acetone and nitrogen in the vapor apace.
-------
TABLE 19. UTILITY REQUIREMENTS
STEAM
EX-1
EX-2
Distillation Unit
Dryer Unit
TOTAL
34 Ib/hr
26 Ib/hr
800 Ib/hr
60 Ib/hr
920 Ib/hr
COOLING WATER
EX-3 1 GPM
Distillation Unit 70 GPM
Dryer Unit 6 GPM
TOTAL 77 GPM
PROCESS WATER
ELECTRICAL
TX-4
CONNECTED LOAD
90 KVA
1 GPM
ESTIMATED ENERGY
CONSUMPTION
65 KW
522 KWH for an
8-Hour Shift.
153
-------
*>/v
Figure 94. TEU Plot Plan.
-------
/ij't" T
o
Figure 95. TEU Front Elevation.
155
-------
Figure 96. Tail-End Unit Sketch
156
-------
7.1.1.2 Coal Drying System
The coal drying system is sized for 500 Ib/hr coal containing 15 wt.
% volatiles and drying to a coal product containing 0.5 wt. % volatiles.
The dryer is a closed loop system utilizing inert gas as the drying media.
The coal is fed to the dryer from the centrifuge where it is contacted with
a hot inert gas stream and dried at 225°F. The dried coal is cooled and
conveyed into dumpsters via the screw cooler (CD-SC-1). The inert gas off
the dryer containing acetone and water passes through the cyclone separator
(CD-CY-1), the recycle gas blower (CD-B-1), condenser (CD-E-2) and the
condensate receiver (CD-V-1). The acetone condensate is pumped to the
distillation feed storage tank (TX-2) and the gas is recirculated to the
dryer after heating to 400°F in the recycle gas heater (CD-E-1).
7.1.1.3 Acetone Recovery System
The distillation feed storage tank (TX-2) is sized to accumulate
enough acetone/water mixture to allow for one week of continuous operation
of the contacting system at the 500 Ib/hr coal rate. The acetone dis-
tillation system is designed for a feed rate of 2 gpm acetone/water mixture
with the overhead product to be 98.5% acetone. The column which is 14 inch
diameter with 30 trays will operate at 30 psig such that the sulfur in the
bottoms will be molten. The acetone overhead product is pumped to the
underground acetone storage tank (TX-1) which is sized to contain enough
acetone for a seven day run at design rates. The bottoms product con-
taining water and molten sulfur is pressured to the molten sulfur
accumulator (VX-3) where the sulfur phase is decanted into drums for disposal
The molten sulfur accumulator is designed to hold one week's production of
sulfur at the design rate. The water phase from the molten sulfur accumu-
lator is cooled in exchanger EX-3 and stored in the bottoms storage VX-4
which is sized to hold enough material for two weeks operation. The water
phase material in the bottoms storage 1s pumped to the neutralizers
(TX-6A & B) where the material is neutralized with lime or held in the
waste water storage (TX-5) for disposal. All of the processing equipment
1n acetone service is blanketed with nitrogen and vented to a common acetone
scrubbing system. The scrubbing system consists of a chilled condenser
157
-------
(EX-4), acetone K.O. drum (VX-6), a carbon bed adsorber (VX-5) which con-
tains disposable cartridges, and a recirculated water scrubber. The
condensed acetone 1s returned to the distillation feed storage for reuse.
The spent scrubber water 1s pumped to the waste water storage tank (TX-5)
and held for disposal.
7.1.2 TEU Design Basis
The overall TEU conceptual design is based on a processing unit capable
of handling a nominal throughput of 500 Ibs/hr of coal sized up to 8 mesh
top-size. The plant is designed to operate on a continuous basis with
sufficient liquid storage capacity to allow for up to 7 days of uninter-
rupted run duration. The specific design basis for each piece of major
process equipment Is presented 1n Table 20.
7.2 TEU COST ESTIMATE
An estimate of the cost to fully engineer, specify, procure and con-
struct the TEU adjacent to the RTU at TRW's Capistrano Test Site was
completed. The overall cost estimate is generally of a factored nature
based primarily on FOB major equipment costs. The equipment list and
associated equipment costs (FOB) are presented in Table 21. As may be
determined from the list, the total FOB major equipment cost is estimated
to be $387,200 (mid 1978 basis). A complete construction cost estimate is
shown in Table 22. The elements of the total estimate are delineated in
Table 22 as 1s the source of each estimated value. As may be seen, the
total estimated cost (escalated to mid 1979) to engineer the TEU, specify
and procure all required equipment, and completely construct the unit is
$1,727,700.
158
-------
TABLE 20. TEU EQUIPMENT DESIGN BASIS SUMMARY
en
vo
Equipment
Number
TX-1
TX-2
TX-3
TX-4
TX-5
TX-6
VX-1
VX-2
Service
Acetone Storage
Distillation Feed
Storage
Coal Feed Bin
Vent Gas Scrubber
Waste Water Storage
Neutrallzera
Coal/Acetone
Contactor
Centrifuge Liquid
Surge
Design Basis
Sized to contain enough acetone for a 7-day production run using
1000 Ibs of acetone per hour to contact the coal in VX-1.
This tank will be underground.
Sized to accumulate enough acetone/water mixture to allow 1 weeks
continuous operation at an acetone contacting rate of 1000 Ib/hr.
This tank will be underground.
Sized to hold 10 tons of coal feed with a coal bulk density of
50 lb/ft3.
Removes any vapors from vent streams prior to exhaust to atmos-
phere. Operates at atmospheric pressure and uses water at the
scrubbing medium.
Sized to hold 1/2 weeks waste water from the vent gas scrubber
(Inlet scrubbing water rate of 1 gpm) and the distillation
bottoms stream (33 Ib/hr.).
These are 55 gal, open-head drums for making teat and sample
quantities of by-product for further evaluation.
Sized for 1 hour residence time using 2/3 of the available
volume at maximum (adjustable) wler height. Maximum coal rate
is 500 .Ib/hr and maximum acetone rate is 1000 Ib/hr. Minimum
wler height is 1/3 the diameter.
Sized for 1 hour residence time for acetone/water mixture for
maximum acetone contactor rate of 1000 Ib/hr and 88 Ibs/hr
acetone on the solid coal product from the centrifuge.
(Continued)
-------
TABLE 20. (Continued)
Equipment
Number
VX-3
VX-4
VX-5
VX-6
PX-1
PX-2
PX-3
PX-4
PX-5
Service
Molten Sulfur Accumulator
Distillation Bottoms
Accumulator
Carbon Adsorption Panels
Acetone Knock-Out Drum
Acetone Feed Pump
Contactor Heater Pump
Centrifuge Feed Pump
Centrate Storage Pump
Distillation Feed Pump
Design Basis
Sized to allow all sulfur from a 1-week run to accumulate in
60% of the volume of the vessel. This assumes a coal rate of
500 Ib/hr, a sulfur content of 0.4 wt. percent on the incoming
coal, and a 90% sulfur extraction efficiency.
Sized to hold the water product for two weeks prior to disposal
or neutralization.
These are re-chargeable, filter-type panels containing 50 Ibs.
of charcoal that will adsorb 8 Ibs of acetone before replacement
of carbon.
Sized to allow separation between condensed acetone and vapors
vented to atmosphere. This vessel will operate at 0°F.
Supplies acetone from underground storage to the acetone/coal
contactor at a maximum rate of 1000 Ib/hr.
Re-circulates acetone/coal slurry from the first section of the
contactor, through a heater and back to the contactor.
Pumps slurry from the last section of the contactor to the
centrifuge. This pump will be a variable-speed progressive
cavity pump and will operate on level control from the contactor.
Recovers acetone/water mixture from the centrifuge and sends to
underground storage. Assumes acetone/water rate of 1012 Ibs/hr.
(15% volatiles on solid coal from the centrifuge).
Sends acetone/water mixture from underground storage to distilla-
tion package. Assumes distillation package trill run at 2 gpm and
30 psig.
(Continued)
-------
TABLE 20. (Continued)
Equipment
Number
PX-6
PX-7
PX-8
EX-1
EX-2
EX-3
EX-4
Service
Bottoms Discharge
Pump
Scrubber Recirculation
Pump
Water Disposal Pump
Acetone Heater
Slurry Heater
Distillation Bottoms
Cooler
Vent Gas Chiller
Design Basis
Assumes water rate to be 33 Ib/hr (4 gph). At a pumping rate
of 5 g.p.m., a day's accumulation would be discharged to
disposal in 20 minutes.
Pumps water from the scrubber bottoms to a distributor in the
top of TX-4 or to disposal. Enough water must be recycled
to mix with make-up water to keep the packing material wet.
Empties contents of TX-5 to disposal in 3 hours.
Heat acetone from ambient temperature to 133°F. Design duty
is 34,000 btu/hr. Heat transfer coefficient is 130 btu/ft2
hr. °F.
Provides heat to increase coal temperature from ambient to
133°F and to add heat for any losses to ambient in the
contactor. Design duty is 25,500 btu/hr and the heat transfer
coefficient is 130 btu/ft.2 hr °F.
Cools bottoms temperature to 100°F for safe storage and handling.
Design duty is 6200 btu/hr and the heat transfer coefficient
is 60 btu/ft.2 hr. °F.
Cools the vent gas stream to allow greater acetone recovery.
Design duty is 12,500 btu/hr and the heat transfer coefficient
is 25 btu/ft/ hr. °F.
(Continued)
-------
TABLE 20. (Continued)
en
ro
Equipment
Number
MX-1,2 & 3
MX-4
Scale
SX-1
BDX-1
Service
Contactor Slurry Mixers
Portable Drum Mixer
Tote Bin Scale
Slurry Centrifuge
Bin Discharger .
Design Basis
Maintain homogeneous slurry within contactor and promote acetone
contact with coal particles.
Mixes reactants and promotes neutralization reaction.
Provides data on tote bin weight during loading. Maximum gross
weight assumed 6000 Ibs.
Separate liquid and solids. 500 Ibs/hr. coal and 1100 Ib/hr.
acetone and water. Volatile content of coal product to be
15%.
Prevents arching and feeds wet coat to the contactor at a
uniform rate.
-------
TABLE 21. EQUIPMENT LIST AND FOB COST*
Item No.
A-l
A-2
A- 3
AD-1
AD-C-1
AD-E-1
AD-E-2
AD-P-2
AD-V-1
BDX-1
CD-I
CD-B-1
CD-CY-1
CD-D-1
CD-E-1
CD-E-2
CD-P-1
CD-SC-1
CD-V-1
DRX-1
EX-1
EX-2
EX-3
EX-4
Mid 1978
— , — . .
Tote Bin Inverting Hoist - 2 ton capacity
Tote Bin Elevation Hoist - 2 ton capacity
Refrigeration Unit - 1 ton
Distillation Package
Distillation Column - 316 SS
Column Reboiler - 316 SS
Overhead Condenser - 316 SS
Reflux Pump - 1 HP, 316 SS
Overhead Accumulator - CS
Bin Discharger
Coal Dryer Package
Recycle Gas Blower
Cyclone Separator
Dryer - 6 '6"tf x 10 '6", 1 HP, 304 SS
Recycle Gas Heater
Acetone Condenser
Acetone Discharge Pump - 30 GPM, 316 SS, 1-1/2 HP
Discharge Conveyor - 1/2 HP
Liquid Receiver
Bin Discharger Driver - 1 HP, Var. Speed
Acetone Heater - 0.8 ft2, 316 SS
Slurry Heater - 0.7 ft2, 316 SS
Distillation Bottoms Cooler - 1.5 ft2, 316 SS
Vent Gas Chiller - 17 ft2, 316 SS
basis. (Continued)
163
$K, FOB
4
4
3
80
as AD-1
as AD-1
as AD-1
as AD-1
as AD-1
9
91
as CD-I
as CD-I
as CD-I
as CD-I
as CD-I
as CD-I
as CD-I
as CD-I
0.5
.3
.3
.4
2.6
-------
TABLE 21 . (Continued)
Item No. $K. FOB
MX-1,2,&3 Contactor Slurry Mixers - 1/2 HP ea., 316 SS 6.5
MX-4 Neutralizer Mixer - 1/2 HP, 316 SS .6
PX-1 Acetone Feed Pump - 1.3-2.5 GPM, 1/2 HP, 316 SS 3
PX-2 Contactor Heater Pump - 30 GPM, 1/2 HP, 316 SS 1.4
PX-3 Centrifuge Feed Pump - 1.6-3.1 GPM, 1/2 HP, 316 SS 4.2
PX-4 Centrifuge Storage Pump - 1-3.2 GPM, 1/2 HP, 316 SS 4.2
PX-5 Distillation Feed Pump - 1-3.2 GPM, 1 HP, 316 SS 3
PX-6 Bottoms Discharge Pump - 5 GPM, 1/2 HP, 316 SS 2.5
PX-7 Scrubber Circulation Pump - 15 GPM, 1 HP, 316 SS 1.8
PX-8 Water Disposal Pump - 30 GPM, 1/2 HP, 316 SS 1.8
SX-1 Centrifuge - 6" Solid Bowl, 5 HP, 316 SS 24
SCX-1 Tote Bin Scale - 6000 Ib Capacity, Electric 7.5
TX-1 Acetone Storage Tank - 12' 0 x 22', FRP 46.7
TX-2 Distillation Feed Storage Tank - 12' $ x 22', FRP 46.7
TX-3 Coal Feed Bin - 8' 0x8', 316L SS 15
TX-4 Vent Gas Scrubber - 3' 0 x 4'4", FRP 1
TX-5 Waste Water Storage - 9' 0 x 10'9", FRP 4
TX-6 Neutralizers (2) - 55 Gal, Open Head Drum
VX-1 Coal Acetone Contactor - 2'6"tf x 7'6", 316 SS 5
VX-2 Centrifuge Liquid Surge Drum - 2'6"tf x 4', 316 SS 3.8
VX-3 Molten Sulfur Accumulator - V6"0 x 2'6", 316 SS 3
VX-4 Distillation Bottoms Accumulator - 6' 0 x 6', FRP 2.1
VX-5 Carbon Adsorber - 50 Ib Carbon Cartridges .5
VX-6 Acetone K.O. Drum - 31 0 x 3', 316 SS 3.8
164
-------
TABLE 22. ESTIMATED TEU CONSTRUCTION COSTS
en
in
Element
FOB Equipment
Site Preparation
Concrete
Structural Steel
Piping
Instrumentation
Electrical
Insulation
Painting
Freight
TOTAL DIRECT COST
Sales Tax
Const. Tools
Labor Fringes
Temporary Facilities
Field Staff Supervision
SUB -TOTAL 1
Escalation
SUB-TOTAL 2
Engineering and Office Costs
Contractors Bond
TOTAL
Contractors O.H. & Profit
TOTAL ESTIMATED PROJECT COST
Basis Materials Sub-Contract Labor
TRW Estimate $387,200
$ 17,200
48,000
158,300
140,400 $74,400
101,600 25,400
133,300
5% FOB Equip. 19,400
3.8% FOB Equip. 14,700
3% Mat'l 18,900
648,100 390,900 99,800
6% Mat'l (less frt.)
20% Labor
60% Labor
7% Labor
20% Labor
6% Sub-Total 1
15% Sub-Total 2
TRW Estimate
10% Total
Total
$1,138,800
36,600
20,000
59,900
7,000
20,000
1,282,300
76,900
1,359,200
203,900
7,500
1,570,600
157,100
1 ,727,700
-------
8. APPLICATION STUDIES
8.1 APPLICABILITY OF GRAVICHEM PROCESS FOR U.S. COALS
There are presently two principal methods for the pre-combustion re-
moval of pyritic sulfur from coal; these are the deep physical cleaning of
coal (which segregates an ash and pyrite-rich coal reject from a low-ash,
low-pyrite coal product) and the Gravichem Process for chemically removing
pyrite from coal. Deep cleaning has been practiced for many years, pri-
marily to produce coking coal , while the Gravichem Process is an emerging
technology.
A simplified approach for comparing physical cleaning and the Gravi-
chem Process is offered here. This method compares potential sulfur oxide
emission reduction for regions of the U.S. now using high sulfur coal.
The main data sources are: Steam Electric Plant Factors and Coal Data
published by the National Coal Association?'^ which provide sulfur content,
in Ibs of S0,/10 Btu, for both coal resources and coal consumed and the
9
Bureau of Mines Report of Investigation No. RI 8118, which provides wash-
ability data for U.S. coals and a comparable data base for forecasting the
applicability of both deep cleaning and the Gravichem Process.
The high-sulfur coal regions of the United States are the Northern
Appalachian States of Maryland, Pennsylvania, Ohio and most of West
Virginia; the Eastern Midwest states of Illinois, Indianla and Kentucky
(west); and the Western Midwest states of Arkansas, Iowa, Kansas, Missouri
and Oklahoma. Approximately 59% of all U.S. production (400 x 106 tons)
in 1975 was mined in these three regions, while 66% of U.S. identified
Q
bituminous coal resources (490 x 10 tons) are located there.
The potential sulfur oxide emissions for the coal resources of these
three regions averages 6.1 Ibs S02/106 Btu (Table 23), while actual coal
mined and consumed in these regions has potential emissions of
166
-------
TABLE 23. POTENTIAL SULFUR EMISSIONS OF COAL TREATED BY GRAV^CHEM3 PROCESS COMPARED
WITH DEEP CLEANING^ FOR HIGH SULFUR COAL REGIONS OF U.S.
Regton Process
N. Appalachia
Deep Clean
Gravichem
E. Midwest
Deep Clean
Gravichem
W. Midwest
Deep Clean
Gravichem
Three Regions
Deep Clean
Gravichem
Potential Emissions
ihc sn /in6 Rt,, % 1975 % u-s- Bituminousc
Ibs S02/10 Btu y s prod identified Resources
Coal Resources Coal Consumed
4.8 4.3 37% 28%
3.2
1.8 - - -
6.5 5.3 22% 29%
4.4 - -
2.9 - -
9.0 5.9 2% 9%
6.1
2.9 - -
6.1e 4.9f 61% 66%
4.1
2.4
aGrav1chetn reduction of Inorganic sulfur to 0.2% w/w for coal samples as listed in Reference 10. Gravichem heat content
Increases of 6.3%. 3.3%. and 6.2%, respectively for N. Appalachia. E. Midwest and W. Midwest were used as reported in
Reference 10.
bFloat-sink data on seam samples crushed to 1-1/2" x 0, float all sizes at 1.60 sp. gr., Reference 10.
CReference 8.
^Reference 7. Weighted average by quantity consumed by each state for plants 25 MW or greater. All W. Va. consumption
assigned to N. Appalachia, all Ky. consumption assigned to W. Ky., no figures for Ark. and Okl. for consumption, so
not used in weighted average.
Weighted average based on Identified Resources.
Weight average.
-------
4.9 Ibs SQp/10 Btu. The coal consumed can be lower in potential emissions
than the resource base, due to selective mining and coal cleaning, as
presently practiced.
It can be seen (Table 23) that deep cleaning of coal from these regions,
at 1.6 specific gravity, would give a resource base averaging 4.1 Ibs
SOo/106 Btu while application of the Gravichem Process would give a pro-
6
cessed resource base of 2.4 Ibs S02/10 Btu. Thus, deep cleaning would
have little overall effect on reducing sulfur oxide emissions, if applied
to the coal reserve base. Similar conclusions can be reach on a regional
basis. Sulfur emissions reduction potential of the two approaches in com-
pared in Table 24 on a percentage basis, where it can be seen that a 45-58%
reduction in sulfur oxide emissions can be forecast for application of the
Gravichem Process to the resources of these three regions, while 0-26%
reduction is calculable for deep cleaning. Thus, a fully-developed Gravi-
chem Process could be very important as a sulfur oxide control strategy.
8.2 APPLICABILITY OF THE GRAVICHEM PROCESS FOR WASTE COAL RECOVERY
8.2.1 Coal Oil or Coal Water Mixtures for Boiler Retrofit
The National Energy Plan calls for greatly increased use of coal for
Industrial boiler use through switching of.these boilers from oil to coal.
However, most existing industrial boilers cannot easily switch due especially
to high ash, fouling metals and sulfur in coal as compared to oil In
addition, these boiler units have no coal handling facilities so a pump-
able form of coal is needed. A coal fuel, particularly adaptable to the
switching of oil-fired industrial boilers to coal, could be prepared by
utilizing the Meyers Process ferric sulfate leach solution in a unique way.
Coal tends to be partitioned in the leach solution (which has a specific
gravity varying between 1.3 and 1.5 according to the concentration) into a
float fraction which was exceptionally low in ash and fouling metals and
nearly free of pyrite, and a sink fraction containing most of the coal
pyrite and ash which can be rejected.
The light and purified float coal can then be slurried in either oil
or water and stabilized in suspension to provide a fluid fuel which can
168
-------
TABLE 24. SULFUR EMISSIONS REDUCTION POTENTIAL OF GRAVICHEM
PROCESS COMPARED WITH DEEP CLEANING
Region
N. Appalachla
E. Midwest
W. Midwest
aCoal consumed - coal
Process
Gravlchem
Deep Clean
Gravlchem
Deep Clean
Gravlchem
Deep Clean
resources , . tjl . - .
Reduction of Present
Sulfur Em1ss1onsa
58%
26%
45%
17%
51%
0
To 9T
coal consumed
be pumped and burned much like oil. An Ideal raw material source for this
"Gravlfloat" fuel 1s waste coal.
Over 3 billion tons of h1gh-ash fine coal exist above ground 1n waste
gob piles and slurry ponds , the result of years of crushing and cleaning
operations 1n the Eastern portion of the United States. This reserve 1s
largely unusable as 1t 1s mainly the high ash low heat content reject from
cleaning plants and 1s too fine for conventional heavy media cleaning.
However, gravity separation at 1.3-1.4 specific gravity would float-out a
uniform product containing 3-4% ash and having heat content 1n excess of
13000 Btu/lb,
The use of ferric sulfate leach solution as homogeneous heavy media
offers a nearrterm technology for recovery of these resources. Most con-
ventional heavy media cleaning devices make use of dispersed and agitated
magnetite particles. This media 1s Incapable of cleaning fine coal at
low specific gravity as 1s required for recovery for high quality fuel from
gob.
169
-------
Results for an Ohio waste coal are shown 1n Figure 97. The removal
of coal Iron impurity by the addle leach solution wash gives an additional
benefit: the ash fusion temperature 1s raised to the level required for
retrofit of non-slagging o1l-f1red burners. The product float coal, fed
to a previously o1l-f1red Industrial boiler as a coal-oil slurry would be
the simplest near-term system for a partial switch to coal. The re-
sulting mixture 1s near Ideal for this purpose (Table 25), having an ash
content of only 1-1/2%.
TABLE 25. GRAVIFLOAT COAL OIL SLURRY
Coal 011 Slurries (40% Coal)
Gravlfloat Average Steam Coal
Heat Content 16 - 17,000 Btu/1b 15,000 Btu/lb
SO, 1 - 2-1/2 lbs/106 Btu 4 lbs/106 Btu
Ash
Fouling Metals
1 - 1-1/2%
< 1/2%
7%
2%
8.2.2 Gravlfloat Process for Recovery of High Grade Fine Coal from Slurry
Ponds
A summary of Gravlfloat results previously presented 1n Section 5, for
waste slurry pond fines from three states 1s shown 1n Table 26. Gravl-
float coal yield 1s presented 1n terms of heat content (Btu) recovery.
It can be seen that the Btu recovery obtainable from each waste slurry
pond 1s large (40-781), the sulfur content per unit heat content 1s re-
duced by 48-58% and the ash level 1s very low. Note that all of the ash
levels can be reduced to the 3-4% level by working at specific gravities
very near 1.30. The gravities utilized 1n these cases were selected to
give a balance of high yield and quality coal rather than only to minimize
ash.
170
-------
1.3 sp gr
f
1/3
Gravi-float
coal
2/3
Reject
3% ash
13600 btu/lb
2% sulfur
0.2% Fe
2500°F fusion T
25% ash. 9500 btu. 3% sulfur,
1.3% Fe, 2200°F fusion T
AN OHIO QOB POND
Figure 97. Gravlfloat Processing of an Ohio Waste Coal
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TABLE 26. GRAVIFLOAT PROCESS RESULTS*
Refuse
Location
OHIO
INDIANA
W.KY.
Specific Gravity
of Separation
Btu Recovery 1 .33
Sul fur/1 bs S02 per TO6 Btu
Ash
Heat Content
Btu Recovery 1 .37
Sulfur/lbs S02 per 106 Btu
Ash
Heat Content
Btu Recovery 1 .33
Sulfur/lbs S02 per TO6 Btu
Ash
Heat Content
t)*f,,** Product
Refuse (Gravifloat Coal)
6.76
24.88*
9566 Btu/lb
7.02
33.79*
9171 Btu/lb
9.39
39.60*
6389 Btu/lb
40*
3.27
3.25*
13630 Btu/lb
67*
3.61
8.68*
12922 Btu/lb
78*
3.93
5.43*
13529 Btu/lb
New
Refuse
60*
2.70
28.48*
9642 Btu/lb
33*
2.43*/9.08
58.25*
5352 Btu/lb
22*
28.13
69.67*
3598 Btu/lb
*Phys1cal separation 1n aqueous ferric sulfate and sulfurlc acid solution, e.g. 6.0* Fe2(S04)3 and 6.0* H2$04 gives
1.33 specific gravity.
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The W. Kentucky and Ohio Gravifloat coals should be particularly use-
ful for production of low-ash coal-oil or coal-water slurries for boiler
retrofit situations.
As an example, the Gravifloat separation unit could be set up at the
W. Kentucky slurry pond location or one like 1t and operated at near 1.30
specific gravity to produce a 50% w/w float fine coal - water slurry con-
taining coal with ash content near 3%. No final dewatering or drying step
would be needed. A suspending thixotropic agent would be added so that
the fine coal would not settle and the slurry could then be pumped into
a tank truck and delivered for use as an oil substitute. Some modification
1n the oil-fired furnace would be necessary but this would be minimized by
the extremely low ash of the coal. An Improved particulate collection unit
would also be needed.
8.2.3 Waste Coal Recovery from TVA Mine
The recovery of high grade fuel from a waste slurry pond associated
with a Tennessee Valley Authority mine was pursued with some diligence,
starting with selection and obtaining of the sample and continuing
through evaluation of the usefulness of the results.
An excerpt of a letter to the TVA is reprinted below. This letter
highlights the applicability of the subject process for a specific
preparation plant waste.
The mine operator, Peabody Coal, was also contacted. Their response
Indicated surprise at the relatively high grade fine coal which was being
ponded 1n apparent contradiction to the specified cleaning plant efficiency,
Our Impression was that they intended to try to tighten up operation of the
cleaning plant rather than recover the waste. It remains to be seen
whether this can be accomplished or whether the slurry pond will continue
to receive the quality of coal investigated in this study.
173
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19 March 1979
Mr. Randy Cole
Project Manager
Tennessee Valley Authority
1320 Commerce Union Bank Bldg.
Chattanooga, Tenn 37401
Dear Randy:
The sample of waste coal which you sent to us from the Camp #11 mine
(Morganfleld, Kentucky) was processed In our laboratories utilizing
accelerated float sink separation 1n a water solution of Iron sulfate
(Gravlfloat Process), The waste coal, which had a top size of less than
1/8 inch, was Indeed a waste coal. It contained near 40% ash and more
than 9 1 bs S02/106 Btu. Gravifloat separation gave near 50% weight yield
and a 78% Btu yield of superb float material which meets the Kentucky
state standard of 4 Ibs S02/106 Btu as shown 1n the table below.
Waste
Gravi
Gravi
Coal
float
sink
Yield
Weight
-
48%
52%
Btu
-
78%
22%
Sul
3.
2.
5.
fur
94%
66%
06%
Heat Content
Ash Btu/lb
39
5
69
.60%
.43%
.67%
8389
13529
3598
Ibs S02/106
9
3
28
.39
.93
.13
Btu
The sink reject contained only 22% of the waste coal heat content. Frankly,
I know of no other physical cleaning technique which can perform anywhere
near as well as this - so I find the results quite exciting. The accelerated
float sink separation in iron sulfate solution gave very minimal retention
of sulfate by either float or sink fraction. In fact, analysis showed only
0.01% sulfate retained by float and sink coal after washing.
I can envision a practical recovery of about 3/4 of heat content of fine
waste coal associated with the Camp #11 mine, using the Gravlfloat Process,
which would provide a product coal to meet Air Pollution Control Standards
for electric utilities and industrial boilers. In this latter case, gob
derived Gravifloat product could be blended with oil to form a COM con-
taining about 3% ash which would be ideal for retrofitting oil-fired
industrial boilers. Alternatively, the coal could be briquetted or
agglomerated for stoker fuel.
Sincerely,
Robert A. Meyers
174
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9.0 REFERENCES
1. Hart, W.D., L.C. McClanathan, R.A. Orsini, R.A. Meyers and M.J. Santy.
"Reactor Test Project for Chemical Removal of Pyritic Sulfur from Coal,"
EPA-600/7-79-013a and b (1979).
2. Meyers, R. A., L.J. Van Nice, E.P. Koutsoukos, M.J. Santy and R.A.
Orsini. "Bench-Scale Development of Meyers Process for Coal Desulfurization,"
EPA-600/7-79-012 (1979).
3. Meyers, R.A., E.P. Koutsoukos, M.L. Kraft, R.A. Orsini, M.J. Santy
and L.J. Van Nice. Meyers Process Development for Chemical
Desulfurization of Coal. Report No. EPA-600/2-76-143a, Vol. I and II,
prepared by TRW Systems and Energy for the U.S. Environmental Protection
Agency, Research Triangle Park, North Carolina, 1976.
4. Hamersma, J.W., E.P. Koutsoukos, M.L. Kraft, R.A. Meyers, G.O. Ogle
and L.J. Van Nice. Program for Processes for the Selective Chemical
Extraction of Organic and Pyritic Sulfur from Fossil Fuels. Report
No. 17270-6011-RO-OO, Vol. I and II, prepared by TRW Systems and
Energy for the U.S. Environmental Protection Agency, Research Triangle
Park, under Contract No. EHSD 71-7, North Carolina, 1973.
5. Nekervis, W.F. and E.F. Hensley. Conceptual Design of a Commercial
Scale Plant for Chemical Desulfurization of Coa. Environmental
Protection Technology Series, EPA-600/2-75-051, 1975.
6. Van Nice, L.J. and M.J. Santy. Pilot Plant Design for Chemical
Desulfurization of Coal. Environmental Protection Technology Series,
EPA-600/2-77-080, 1977.
7. Steam Electric Plant Factors. National Coal Association, Washington,
D.C. (1977).
175
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REFERENCES (Cont'd)
8. Coal Data 1976, National Coal Association, Washington, D.C. (1977).
9. J.A. Cavallaro, M.J. Johnson and A. W. Deurbrouck, Sulfur Reduction
Potential of Coals of the United States. Bureau of Mines Report No.
RI 8118 (1976).
10. J. W. Hamersma, and M. L. Kraft (TRW Inc.), "Applicability of the
Meyers Process for Chemical Desulfurization of Coal: Survey of
Thirty-Five Coals," Environmental Protection Technology Series,
EPA-650/2-74-025a (1975).
11. "Underground Disposal of Coal Mines Waste," Environmental Studies
Board, National Academy of Sciences/National Science Foundation,
Washington, D.C. (1975).
176
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TECHNICAL REPORT DATA
(Please read /no/actions on the reverse before completing)
REPORT NO.
EPA-600/7-79-240
2.
3. RECIPIENT'S ACCESSION NO.
TTITLE AND SUBTITLE
preservation of Reactor Test Unit and Desulfurization
of Gob Pile Samples
5. REPORT DATE
November 1979
6. PERFORMING ORGANIZATION CODE
r.D.Hart, L.C.McClanathan, R.A.Meyers, and
P.M.Wever
8. PERFORMING ORGANIZATION REPORT NO.
[""PERFORMING ORGANIZATION NAME AND ADDRESS
TRW Defense and Space Systems Group
One Space Park
Redondo Beach, California 90278
10. PROGRAM ELEMENT NO.
INE825
11. CONTRACT/GRANT NO.
68-02-1880
^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
Final; 6/78 - 7/79
14. SPONSORING AGENCY CODE
EPA/600/13
•^.SUPPLEMENTARY NOTES JERL-RTP project officer is Lewis D. Tamny, Mail Drop 61, 919/
541-2709.
ii. ABSTRACT The repOrt gjves results of preservation and desulfurization studies asso-
ciated with the Reactor Test Unit (RTU), an 8-ton per day test plant used in the EPA-
sponsored development of the Meyers Process for ferric sulfate leaching of pyritic
sulfur from coal. RTU operation in 1977 and 1978 showed that it could be run contin-
uously on three shifts to reduce the sulfur content of the feed coal to meet the 1.2 Ib
SOx Emission Standard for New Stationary Sources. Corrosion was encountered in
the stainless steel main reactor vessel which required modification prior to further
testing. The present program provides a complete corrosion assessment, establi-
shed specifications for a tail-end elemental sulfur extraction unit, and developed
maintenance and upkeep requirements for the RTU. A Meyers Process modification,
Involving a preliminary float and sink operation in the ferric sulfate leach solution,
followed by Meyers processing of the sink (high pyrite) fraction was investigated at
bench scale. Experimental verification and applicability assessment of this new
nine coal.
KEY WORDS AND DOCUMENT ANALYSIS
" DESCRIPTORS
pollution Iron Sulfate
Corrosion Prevention Titanium
2oal Maintenance
Desulfurization
pyrite
Beaching
•^DISTRIBUTION STATEMENT
Release to Public
b.lDENTIFIERS/OPEN ENDED TERMS
Pollution Control
Stationary Sources
Meyers Process
Gob Piles
19. SECURITY CLASS (This Report)
Unclassified
20. SECURITY CLASS (This page)
Unclassified
c. COSATI Field/Group
13B
11L,13H
08G,21D
07A,07D
07B
15E
21. NO. OF PAGES
189
22. PRICE
17-
Form 2220-1 (i-73)
177
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