I
K. C. CHANNABASAPPA and H.
R.
LINDEN
institute of Gas Technology, Chicago, ill.
Fluid-Bed Pretreatment of Bituminous Coals and lignite Direct Hydrogenation of Chars to Pipeline Gas
STUDIES
of methods for supplementing base-load natural gas requirements have indicated that conversion of coal to highmethane content gas, where long-distance transmission lines pass through coal fields neaPmajor market areas, may be the most economical method for transporting this source of energy to the domestic consumer in readily usable form, One method for producing pipeline gas-gas with a heating value of approximately 900 B.t.u./SCF (standard cubic foot, a t 60' F., 30 inches of mercury pressure, saturated with water vapor)-is direct hydrogenation of lowrank coals to methane (3-5, 7-77, 27). The residual char may be used to make hydrogen by suspension-gasification with steam and oxygen, or for fuel. Essentially complete hydrogasification of lignites and some subbituminous coals may also be feasible; hydrogen could be produced by reforming product gas or a relatively small portion of the primary natural gas supply. Hydrogasification has three major advantages over the two-step partial coal oxidation-synthesis gas methanation process: (7, 24) large reduction, or potential elimination, of oxygen requirements; elimination of the extreme synthesis gas purification requirements prior to catalytic methanation; and greater thermal efficiency through reduction of exothermic heats of reaction (26). These potential advantages should justify a major effort to determine whether a hydrogasification reactor can be designed, for large throughput rates, and with facilities for residual char removal. Batch reactor tests, engineering studies, and operation of pilot plant models, indicate that optimum design requires fluid-bed operation with parallel upward flow of dry pulverized coal and hydrogen at 1300' to 1400" F. and pressures of more than 1000 p.s.i.g. A thorough knowledge of the agglomeration and hydrogasification characteristics of available coal feeds is essential for successful operation. In the first phase of this investigation, it was demonstrated in batch reactor tests that essentially olefin-free gases containing 60 to 80 volume yo methane could be produced by hydrogasification of a n Illinois bituminous coal (26), a Wyoming subbituminous coal, and,North Dakota lignite a t 1350' F. and 2500 to 3500 p.s.i.g. By adjustment of hydrogen-coal ratios, gasifications on an ash-
and moisture-free basis up to 80 weight % were obtained with bituminous coal, and over 90 weight % with lignite. After preheating of coals in the batch reactor to 600' to 700" F. a t atmospheric pressure in a nitrogen atmosphere, the rate of high heating value gas production was substantially increased a t the expense of converting a relatively small portion of the coal to low heating value gases during pretreatment. However, the residues a t the end of hydrogasification were agglomerated, most severely with bituminous coal. As this would hinder smooth operation of a continuous fluidbed hydrogasification unit, a pretreatment step yielding nonagglomerating, reactive chars was needed. Much of the published information useful in selecting pretreatment conditions has been obtained in thg development of processes for production of smokeless fuels, and in studies of upgrading of coals of high moisture content and low rank for power plant, carbonization, and metallurgical uses (76, 20-23, 25). Of particular interest are investigations of reducing the caking or agglomeration tendencies of coal. Thermal pretreatment a t temperatures hp to 800" F. for partial removal of volatile constituents, often in the presence of an oxidizing atmosphere, is general (6, 77, 79, 25). Control of agglomeration by dilution with recycle char (75) and with inert solids (73) has been recommended. Preheating in inert atmospheres before hydrogenation eliminates a considerable fraction of the oxygen content as carbon oxides, raising the "available" hydrogen content of the coal (29). The effects of temperature, residence time, and atmosphere on the quantity and composition of the gas evolved in the distillation of low-rank coals have been investigated extensively (72, 74). As the temperature is raised, oxygen-containing substances break down to form water, carbon dioxide, and carbon mon-. oxide. Highest carbon dioxide evolution occurs between 400' and 600' F. As temperatures are increased further, bituminous and subbituminous coals evolve mainly hydrocarbons and hydrogen; lignites evolve mainly carbon oxides. Considerable literature exists on pretreatment of coal with acids, acid salts, nitric oxide, sulfur or sulfur compounds, and caustic prior to hydrogenation (78). However, the relative effects of these pro-
cedures on coal reactivity are not clearly defined. Apparatus and Procedure
,
The laboratory-scale coal pretreatment unit consisted of a borosilicate glass fluid-bed retort, 1 3 / 4 inches in inside diameter and 301/, inches long, with a disengaging section 3l/s inches in inside diameter and 15 inches long. The retort closure was equipped with a thermocouple well 11/32 inch in outside diameter, which extended nearly to the bottom of the reaction zone. The retort was heated by two circular electric furnaces. The lower was 5 inches in inside diameter and 12 inches long and had a rating of 2.5 kw.; the upper was inches in inside diameter and 12 inches long and had a rating of 1 kw. The disengaging section was heated with an electrothermal tape. The unit was also equipped with a cyclone separator and a water-cooled condenser. Batches of powdered coal (0.75 pound, 88 to 98 weight yo through 100-mesh) were dried a t 110' C. ( 2 ) ; the dry coal was charged to the reactor a t room temperature and heated a t about 12" F. per minute. Measured volumes of nitrogen, air, carbon dioxide, or steam, a t rates sufficient to keep the coal bed fluidized, were preheated in an electric furnace to 800" to 1000° F. and introduced a t the bottom of the retort. Temperatures a t the bottom, center, and upper zones of the retort were sensed with Chromel-Alumel thermocouples and measured by a wheelco temperature indicator. Pressures were read from a 15-inch standard mercury manometer. The feed gases used as fluidizing media, with the fixed gas evolved from the distillation of the coal charge, were passed through a coarse, fritted-glass disk 60 mm. in outside diameter, kept a t 400' F., and a cyclone separator, to remove the suspended coal particles from the outgoing gas. The gas, after passing through a water-cooled condenser, was measured by wet-test meter and stored in a gas holder. Temperatures, pressures, and volumes of inlet and outlet gases were recorded simultaneously at intervals throughout the run. Gas samples were taken a t intervals by bleeding the sample into an evacuated 200-cc. gas analysis bottle. At the end of the run, the electric current was shut off and a composite gas sample was taken VOL. 50, NO. 4
APRIL 1958
637
Table I.
Proximate, Ultimate, Screen Analyses of Coals High-
Coal Proximate analysis, wt. Yo Moisture Volatile matter Ash Fixed carbon Total Heating value, B.t.u./lb. (dry basis) Ultimate analysis, wt. % (dry basis) Ash Carbon Hydrogen Sulfur Nitrogen + oxymn (by differ.-
Volatile B 4.1 34.6 6.2 55.1
~
+ + + 80mesh
+ 100 mesh
+ 120 mesh $200 mesh - 200 mesh
~
Total from the gas holder. After the retort cooled, it was opened and the solid residue recovered. The weights of the liquid condensate and solid residue were recorded. Product gas samples were analyzed with a Consolidated Engineering Co. Model 21-103 mass spectrometer and specific gravities and heating values were calculated. Product gas volumes and heating values were calculated at 60" F., 30 inches of mercury absolute pressure, and saturation with water vapor, assuming the ideal gas law. Specific gravities were calculated on a dry basis from the average molecular weight of the gas referred to air of molecular weight 28.972. The properties of a sample of the total fixed product gas recovered in the gas holder during pretreatment were generally used to calculate total gas yield data, such as the weight fraction of the coal charge gasified during pretreatment. I n a few instances, the properties of the holder sample did not appear as representative as average properties calculated from incremental volumes and spot analyses of the gases evolved during pretreatment; use of averaged values is noted in the tabulated data. The material balance was calculated from the weights of liquid and solid products recovered a t the end of the run, and from the net weight of fixed gas evolved (total weight of dry product gas less total weight of dry feed gas). The solid residue was subjected to a screen analysis to determine the extent of agglomeration and analyzed (2). An average sample of the residue from pretreatment was crushed to -60 mesh and charged to a 1-liter batch hydrogasification reactor to determine the gas yields and compositions obtainable at 1350' F. and about 3000 p.s.i.g., with a
638
11.0 38.7 4.7 45.6 100.0
22.0 29.0 8.1 40.9 100.0
-
13,600
11,300
10,800
6.5 75.6 5.20 1.71
5.3 66.6 4.65 2.46
10.4 65.3 4.29 0.31
10.99 100.00
20.99 100.00
19.70 _ _
0.1
...
...
100.0
Total Screen analysis, wt. % 40mesh 60mesh
Lignite
-
--
en&)
Subbituminous A
2.5 0.9 8.4 9.1 20.7 58.3 100.0
100.00
0.8 1.0
1.0 1.0 0.1 2.7 9.6 85.6 __ 100.0
...
3.2 5.9 89.1 __ 100.0
hydrogen-char ratio of about 17 SCFjlb. The apparatus and procedure for hydrogasification tests have been described (26). Solid residues were again subjected to screen analyses to determine the extent of agglomeration. Yields and Characteristics of Pretreatment Products
The proximate, ultimate, and screen analyses of the pulverized coals used in pretreatment studies are shown in Table I. Before charging to the bench-scale fluid-bed unit, the samples were dried at
INDUSTRIAL A N D ENGINEERING CHEMISTRY
110" C. The product yields and com positions after pretreatment for 50 to 75 minutes in nitrogen, air, carbon dioxide, and steam at flows of 4 to 6 SCF/lb. of dry coal per hour and maximum temperatures of 400" to 720" F., are summarized in Table 11. Fixed Gases. I n all runs the cumulative volume of fixed gas evolved increased with increases in pretreatment temperature, as illustrated in Figure 1. The gases consisted primarily of carbon dioxide (lignite and subbituminous coal) and gaseous hydrocarbons and hydrogen (bituminous coal). After attainment of constant temperature, the rate of gas evolution decreased markedly with residence time, as shown in Figure 2 for steam atmosphere runs with lignite and bituminous coal at maximum pretreatment temperatures of 520" and 620" E'., respectively. The influence of feed gas type on the composition and rate of evolution or fixed gases was somewhat obscured by excessive dilution of the evolved fixed gases with nitrogen, air, or carbon dioxide (Table 11). This limited the accuracy of calculated quantities and compositions of net fixed gas yields. In Figure 3, the yields of carbon dioxide and gaseous hydrocarbons (including sulrur compounds) are plotted as a function of pretreatment time for runs with bituminous coal at approximately 600" F. maximum temperature. Compared to the other atmospheres, steam reduces carbon dioxide evolution from this coal and increases hydrocarbon evolution. Hydrocarbon evolution seems to be relatively high in a carbon dioxide atmosphere and low in air. Pretreatment results for subbituminous
TCI
THERMOCOUPLES
AIR
9
& WET TEST METER
,!8 @
VA R 1 ABLE TRANSFORMER PRGEpSFRE
Fluid-bed laboratory unit for pretreatment of coal
BITUMINOUS COAL HYDROGENATION ,
121
1
PRETREATMENT IN S T E A M ATMOSPHERE
,
' N. D. LIGNITE
STEAM FEED.4 7 9 - 5 . 4 5
%FILE. COAL- HR. I .o PRETREATMENT=
60-65 MIN. i i i :
I
too
,
l
i
00
i
08
+- 6 0
r
-
W 40 06
w
3 20 0 4
0
PRETREATMENT AT 605' N9 AIR
0 2
0 300
400
500
600
CARBON DIOXIDE
Figure
CARBON MONOXIDE
STEAM
400 500 600 700 T E M P E R A T U R E , OF,
PR E T R E A T MENT
f a 1.
- 620" F.
HYDROCARBS
0
t S COMP'DS
Composition and yield of pretreatment gases
ILL. BITUMINOUS
-STEAM FEED 0 4.87 - 700 SCFILB. COAL- He. 1 n -
SCF/LB. COAL-HR.1
0
I
I
/I
I
i
+ 40 MESH
'600
f100MESH
+ 2 0 0 MESH
n- 2 0 0 M E s n
Figure 4. Effects of pretreatment temperature and atmosphere on particle size of bituminous coal char
0 J
0.4
Figure 2. Rate of evolution and composition of Pret r e t m e nt gases
W
t
0.2 v,
U 0
2
0 0
20 40 60 PRETREATMENT
20 40 TIME, MINUTES
0
60
Figure 3.
Effect
of atmosphere on rate of evolution of pretreatment gases from bituminous coal
PRETREATMENT
T I ME, M I N U T E S
coal and lignite (Table 11) indicate that the tendency of these coals to evolve more carbon dioxide and less hydrocarbons than bituminous coal, observed in a steam atmosphere, applies, in general, to the other atmospheres. No consistent effect of feed gas type on fixed gas evolution was apparent. Residual Chars. The chars showed relatively uniform decreases in volatile matter with increases in pretreatment temperature, independent of other pretreatment conditions (Table 11) ; the
effects of pretreating atmosphere composition on the quantity and composition of fixed gases evolved were not reflected in the proximate analyses. Ultimate analyses of selected chars showed little variation with pretreatment conditions from 500" to 700" F., with compositions, on a weight basis, ranging 72 to 75% carbon, 3.9 to 4.4% hydrogen, 0.7 to 1.4% sulfur, and 9 to 11% ash. However, the extent of agglomeration varied considerably with the composition of the pretreatment atmos-
phere and pretreatment temperature. Figure 4 indicates a well-defined trend of increases in agglomeration with increases in temperature for the pretreatment of bituminous coal in a steam atmosphere, and a tendency for considerably greater agglomeration in carbon dioxide and steam atmospheres, compared to nitrogen and air. The greater agglomeration of bituminous coal in steam and carbon dioxide appeared to be related to the large evolution of hydrocarbon gases under these conditions. I n contrast, subbituminous coal and lignite did not agglomerate significantly over the entire range of pretreating conditions. This follows the trend of decreases in agglomeration with decreases in hydrocarbon evolution. However, subbituminous coal and lignite tended toward increased agglomeration a t the higher temperatures, and in steam and carbon dioxide atmospheres. In all pretreatment runs, the amount of dried coal converted to gases was small (2.5 to 9.9 weight % of charge). The heating value of the total product gases was low, normally less than 200 B.t.u./ SCF, except in steam pretreatment runs, in which gases with heating values from 200 to 1000 B.t.u./SCF were evolved. Hydrogenolysis Characteristics
of Pretreated Coal The reactivities of the chars in respect to gaseous hydrocarbon formation were evaluated in batch hydrogasification tests a t 1000 to 1010 p.9.i.g. initial hydrogen pressures a t room temperature, approximately 60-gram sample size, 1350" F. maximum reaction temperature, and VOL. 50, NO. 4
APRIL 1958
639
ln
IN
x
d:
m
Na
N
'92i orij -r
N
x
4
N
m
0
Bo" ov 7
:-4
-r o m
.tr
1
m
d: o
W
W
m
m
1
3
P r'! m
9 .. .*.hva-i ?0r ?3 *9N.m . w 3 0 1 00 .
?
,
W
m
3
10
N.
W
-r m
10
1
In
m
1
r.
N. 1 m W
?
m
o
:-;odd
0
m
x
mo
O N O N W h
'9
2
h 3
m -r
: : 1
vi
0
L:
0
r-
9 m
3
2 1
9
3
W
0: 0: h
h
m W
1
vi
9
4 9 W 3
?
1
h
m
10
x :
1
m
m
N
m
vi
m
h
1
09
1
N
\o
-r
3
m
m
i
7
dV
, I
m
00
W
'9
'9
3
.L h
m
4 W
mm
3
m
6W
N. N
N.
2 m
m ! m W
m
?
m ? vi 1 h
h
L .
.. .. .. .. .. .. .. .. .. .. ..........
s0:N.d: 3
m w w. m
'049 9
w 3o WmI/Oo N 3
?
m
'9YL:vi
N
vi
1
I
?
m
0
Q
1
3
PI
w 1 0 .
W
vi 1 N 0
Eo" m W
m a wlo m m 1o 3
r'!
1
m
??vi ?
3
0: o
h
m
640
L:
3
1
h
m
: :9 :m 0
W
INDUSTRIAL AND ENGINEERING CHEMISTRY
m
4
L:
1
4L:?p!
0 0 h 3 131
E?:'; N
W P
BITUMINOUS COAL HYDROGENATION 25-minute run at maximum temperature. These charge quantities corresponded to a hydrogen-coal ratio of 17 SCF/lb. and gave maximum reactor pressures of 2900 to 3300 p.s.i.g. (Table 111). The char charge to the reactor was obtained by sampling the residual chars from the pretreatment runs with a small riffle sampler and crushing to -60 mesh. The threshold temperatures reported in Table I11 correspond to the point at which the number of moles of gas in the reactor passed through a maximum due to initiation of hydrogenolysis. Reactor pressures increased nearly linearly with increases in temperriture up to the threshold temperature (950' to 1050' F.) and passed through a maximum at 1100' to 1200' F. As the reactor attained the maximum run temperature, the pressures decreased rapidly and continued to decrease at a lower rate during the remainder of the run. These characteristics were similar to those reported previously (26). Effects of Pretreatment Conditions on Hydrogenolysis Yields. The net B.t.u. recoveries (product of gas yield and heating value, minus initial hydrogen heat of combustion) and gaseous hydrocarbon yields for each coal fell within relatively narrow limits because of the similarity in char properties (Table 111). However, optimum conversion to hydrocarbons a t the time the reactor attained 1350" F. occurred with bituminous and subbituminous coal chars prepared at 600' F., and lignite char prepared at 500' F. Comparison of results for chars prepared at these optimum temperatures in nitrogen, air, carbon dioxide, and steam, shows net B.t.u. recoveries of the chars prepared in a carbon dioxide atmosphere to be lower for each coal. These data indicate that optimum pretreatment conditions for hydrogasification yields result from two factors: (1) increase in reactivity of the char to a maximum value as pretreatment temperature is increased, followed by decrease as low-temperature carbonization temperatures are approached, and (2) continuous decrease in relatively easily hydrogenable materials as pretreatment temperature is increased. The increased quantities of coal converted to liquid products with increases in pretreatment temperature (Table 11) indicate loss of the more reactive coal constituents, which eventually offsets any general increase in reactivity due to pretreatment. In Figure 5 the rates of methane-plusethane production from 705' F. air pretreated, and from dried bituminous coal, are compared. At least 10 additional minutes of residence time a t 1350" F. would be required for the dried coal to yield product gases similar to those obtained with pretreated coal at the time the reactor attained 1350" F. In Table
1V the effects of steam and air pretreating on hydrogasification rates are shown for bituminous coal and lignite. A gas of 67.5 mole % methane-plus-ethane content was produced from the pretreated sample (run 112) upon attainment of a reactor temperature of 1275" F., or 15 minutes before reaching the maximum reaction temperature of 1350' F.; in the comparable test with dried coal (run 67) the product gas contained only 21.1 mole % methane-plus-ethane when a reactor temperature of 1350' F. was attained. Pretreatment Losses. Because of evolution of substantial amounts of gaseous hydrocarbons and liquid products during pretreatment of bituminous coal (Table 11), the increase in reactivity to hydrogenation was accompanied by a decrease in ultimate gaseous hydrocarbon yield and net B.t.u. recovery. However, a substantial portion of these pretreatment losses can be recovered as fuel gases during pretreatment; steam pretreatment of bituminous coal yields product gases of high heating value suitable for addition to the pipeline gas formed in hydrogasification. Pretreatment is essential in reducing or eliminating agglomeration of coking or caking coals to be used as feeds to moving-bed or fluid-bed hydrogasification processes, so that pretreatment losses must be considered a characteristic of bituminous coal operation. The effects of steam pretreatment on the hydrogasification product distribution for dried Illinois high volatile B bituminous coal are illustrated by runs 67 and 112, Table IV. For approximately equal product gas compositions (after 25 minutes a t 1350' F. for dried coal and 0 minutes for pretreated coal), substantially higher conversions were obtained with dried coal. The relative yields with and without pretreatment are summarized below, based on 100.0 weight units of moisture-, ash-free bitumi-
nous coal and on char or residue yields corrected to 100% material balance (the lower conversion of pretreated coal was probably in part due to the somewhat lower hydrogen-coal ratio).
Pretreatment Products Char (moisture-, ash-free) Net water and other condensates c o , c02 Hydrogen Gaseous hydrocarbons
Steam, 620' F. (Run PR-19)
None
90.4
...
4.4 1.8 Trace
...
... ...
...
3.4 Minutes at 1350' F' 0 25 (Run 112) (Run 67)
Hydrogasification
Feeds Char or coal (moisture-, ash90.4 100.0 free) Hydrogen 8.9 9.4 Products Residue (moisture-, ash-free) 43.1 (43.1) 39.8 Condensates 1.9 (6.3) 5.0 CO, CO2, N2 3 . 4 (5.2) 4.7 Hydrogen 1.5 (1.5) 1.4 Gaseous hydrocarbons 49.4 (52.8) 58.5 Values in parentheses represent total pretreatment and hydrogasification yields.
The comparative performance of dried and air-pretreated (520' F. maximum temperature) lignite is shown in runs 71 and 140 (Table IV). As there are only minor differences in ultimate gaseous hydrogenation yields, the major benefit of lignite pretreatment would be the increase in product gas heating value (80 to 90 B.t.u./SCF on the basis of Table IV), due to reduction of carbon dioxide content; increases in reactivity would probably not justify pretreatment, and lignite has little agglomeration tendency. The behavior of subbituminous coal appeared to fall between that of bituminous coal and lignite 6,
. J U
0 ln
IO
a A
wr l n 5
a W
0
R E S I D E N C E T I M E AT TEMP,
MIN.
Figure 5. Effect of residence time on hydrogasification yields from pretreated bituminous coal (air at 705' F.) VOL. 50, NO. 4
e
APRIL 1958
641
?vi2 ? * 3 2 *m.? : g o :. :. : . o o oPo
???
. . . . . . : : : d d : 3o m m . . . '2
b w m - ~ a
Fi-
m 3 m o m o
yyq 1 m d: . ? N O 2 :.db d :. :. :. : .o .o
'2
???
m m q
. g o .. .:po? ?o? o *.?o * P
x m
2
0
m rl
mm-l
E!
.b
d
642
INDUSTRIAL AND ENGINEERING CHEMISTRY
..?b?o.. ...,*;.
0
?
. . . . -: o2
BITUMINOUS COAL HYDROGENATION on the basis of less complete data than presented for the other two coals. Agglomeration of Hydrogasification Residues. One objective of the hydrogenolysis tests with pretreated coals was to determine if variations in agglomeration of the hydrogasification residue could be related to pretreatment conditions. Before testing, the char from each pretreatment run was ground to -60 mesh to approximate constant initial conditions. Although this procedure was probably inadequate in so far as the size distribution of - 60-mesh particles is concerned, Figure 6 shows that the degree of agglomeration indicated by the percentage of +40-mesh particles in the hydrogasification residue followed the degree of agglomeration of dried bituminous coal during pretreatment (Figure 4). Increases in pretreatment temperature over the 400" to 720' F. range increased agglomeration of the residue; agglomeration during hydrogasification increased with pretreatment atmospheres
Table IV.
Coal Run No.
in the order: air, nitrogen, steam, and carbon dioxide. H y d r ogasification Characteristics of LowTemperature Chars. An i n d i c a t i o n of t h e r e activities of low-temperature chars produced with Bureau of Mines (22, 23) and Pittsburgh Cons o l i d a t i o n C o a l Co. fluidized carbonization processes can be obtained by comparing batch hydrogasification test results (TableV) with data for pre-
AFTER
.RE
IO0 80 60 (3
-
40
3
20
W
0
AFTER PRETREATMENT AT 6O5O-62O0F N2 AIR COe STEAM - -
Figure 6. Effects of pretreatment temperature and atmosphere on particle size of hydrogasification residues from bituminous coal chars
+ 4 0 MESH
0- 200 MESH
+100MESH
Comparison of Operating Conditions and Results for High-pressure Hydrogasification of Dried and Pretreated . Samples of Bituminous Coal and Lignite Illinois High-Volatile B Bituminous North Dakota Lignite 71
140
Drieda and steam pretreated (S20° F.)
Drieda
Drieda and air pretreated (520" F.)
112
67
Type of pretreatment
Drieda
As received coal charge, gram Pretreated charge, gram Operating conditions Initial pressure, p.s.i.g. Hydrogen/coal charge ratio, SCF/lb. As received Pretreated Threshold temp., OF. Time to reach threshold temp., min. Total time elapsed, min. Run time at temperature, min. Reactor pressure, p.s.i.g. Reactor temp., O F. Operating results Net B.t.u. recovery, MB.t.u./lb. Based on as received coal charge Based on pretreated coal charge Product gas yield, SCF/lb. Based on as received coal charge Based on pretreated coal charge Gaseous hydrocarbon yield, SCF/lb. Based on as received coal charge Based on pretreated coal charge Gaseous hydrocarbon space-time yield, SCFICF-hr.* Net moisture-, ash-free pretreated coal hydrogasified, wt. %C Product gas urouerties Gas composiGon, mole % Nn CO
67.0 60.1
70.1 60.0
60.0 45.1
53.9 40.0
1015
1010
1025
1010
15.17 16.91 1025 45 85 110 0 25 3290 3260 1350 1350
14.36 16.77 977 50 90 102 0 3050 2990 1305 1350
17.42 23.18 1025 52 92 117 0 25 3760 3720 1350 1350
19.23 25.93 964 45 95 120 0 25 2890 2870 1350 1350
+
coz
Hn HzS CH4 CzHi cxH8 plus Olefins Benzene Total Heating value, B.t.u./SCF Specidc gravity, air = 1 a Dried according to (2).
87 ... ... 3060 1275
127 25 3300 1350
2.300 2.564
7.726 8.610
5.827 7.050
6.041 7.049
6.147 7.179
5.981 6.986
8.564 11.394
8.915 11.859
7.442 10.033
7.918 10.676
14.47 16.13
14.34 15.98
13.43 15.69
13.17 15.37
12.58 14.70
12.75 14.89
18.87 25.10
18.67 24.84
16.35 22.04
16.24 21.89
3.12 3.48
11.62 12.94
9.13 10.67
9.39 10.96
9.76 11.41
9.54 11.14
11.45 15.24
13.18 17.54
12.25 16.51
13.01 17.53
21.2
48.6
70.2
66.7
53.4
35.2
68.2
48.3
51.8
36.7
18.5
55.2
50.7
50.2
50.3
50.9
84.6
94.4
69.7
74.2
1.4 0.6 76.4
2.5 0.8 15.7
3.8 0.9 27.2 0.1 67.0 0.5
3.5 0.7 24.4 0.1 70.7 0.4
4 2 ,2 0.6 19.6
4.2 0.7 20.3
3.7 3.4 32.2
3.6 5.0 20.8
2.1 0.4 22.6
2.4 0.4 17.1,
...
17.8 3.3 0.4
...
80.2 0.3 0.2
... ...0.3 0.1 100.0 494 0.2160
100.0 877 0.5046
...
0.1
...
...0.2
... ... 74.4 76.4 0.8 0.2 ... ... ... ... 0.4 0.2
0.4 100.0 100.0 100.0 791 807 853 0.4569 0.4628 0.4849
* Based on time after reactor attained threshold temperature.
loo
100.0 829 0.4835
... ... 57.7 70.4 2.3 0.1 0.3 ... 0.2 ...
0.2 100.0 749 0.4656
0.1 100.0 776 0.5177
... 74.5
...
79.7 0.2
0.2
..... . . .... ..
0.2 0.2 100.0 1.00.0 831 866 0.4626 0.4905
[wt. of product gas - wt. of hydrogen in wt. of moisture-, ash-free charge
VOL. 50, NO. 4
APRIL 1958
1
'
643
(20) Parry, V. F., Combustion 25, 38-42 (March 1954). (211 Parrv. V. F.. Goodman. J. B.. Wacn&; E. 0.; Trans. Am’. Inst. ‘Mini& Met. Engrs. 184, 89-98 (1949). (22) Parry, V. F., Landers, W. S., Wagner, E. O., Mining Eng. 8, 54-64 (1956). (23) Parry, V. F., Landers, ‘IY. S., Wagner, E. O., Goodman, J . B., Lammers, G. C., E. S. Bur. Mines, Rept. Invest. 4954 (1953). (24) Pyrcioch, E. J., Dirksen, H. A., van Fredersdorff, C. G., Pettyjohn, E. S., Am. Gas Assoc. Proc. 1954, pp. 813-36. (25) Reed, F. H., Jackman, H. W.,Henline, P. W., Ill. Geol. Survey, Urbana, Ill., Rept. Invest. 187 (1955). (26) Shultz: E. B., Jr., Channabasappa, K. C., Linden, H. R., IND. ENG. CHEW 48, 894-905 (1956). ’ Stockman, C. H., Bray, J. L., Purdue Univ. Eng. Expt. Station, Lafavette, Ind., Research Ser. 111 (No;ember 1950). Taylor, G. B., Porter, H. C., U. S. Bur. Mines, Tech. Paper 140 (1916). Warren, T. E., Bowles, K. W., Gilmore, R. E., Fuel 19, 72-6 (1940).
(5) Bray, J. L., Morgal, P. W., Zbzd., Rept.Z,ResearchSer.93 (July 1944). (6) Bunte, K., Briickner, H., Simpson, H. G., Fuel 12, 222-32 (1933). (7) Dent, F. J., GUSJ . 244, 502-7 (1944) [Gus World 121, 378-88 (1944)]. (8) Dent, F. J., “Gasification Programme of Birmingham Research Station,” Gas Council (London), Research Commun. GC1 (November 1952). (9) Dent, F. J., “Production of Gaseous Hydrocarbons by Hydrogenation of Coal,” Gas Research Board (London), Publ. GRB 13/3. (January 1950). (10) Dent, F. J., Blackburn, W. H., Millett, H. C., Inst. Gas Engrs. (London), Publ. 167/56 (November 1937); [GUS J . 220, 470, 473-5 (1937)l. (11) Zbzd., Publ. 190/73 (December 1938) [Gas J . 224, 442-5 (1938)l. (12) Ellis, C., “Some Aspects of Coal Pyrolysis,” Inst. Gas Engrs. (London), Commun. 436 (November 1953). (13) Garbo, P. W. (to Hydrocarbon Research), U. S. Patent 2,729,597 (Jan. 3,1956). (14) Gentry, F. M., “Technology of Low Temperature Carbonization,” pp. 39-72, Williams Br. Wilkins, Baltimore, 1928. (15) Lang, E. W., Smith, H. G., Bordenca, C., IND. ENG. CHEM.49, 355-9 (1957). (16) , , Leiher. C. E.. Trans. Am. Inst. Mining Met.‘Engrs.’ 139, 328-63 (1940). (17) Lowry, H. H., “Chemistry of Coal Utilization,” vol. I, pp. 848-62, Wiley, New York, 1945. (18) Zbid., V O ~ .11, pp. 1759-61. (19) Minet, R. G.. Mirkus. J. D.. Chem. Eng: Progr. 52, 531-4 (19561.
treated coals (Table 111). Although coal conversions are quite low, the data indicate the possibility of obtaining gases of high heating value from nonagglomerating chars, from which a major portion of reactive coal constituents has been removed under relatively severe pretreating conditions employed in low-temperature carbonization processes. Acknowledgment The guidance and counsel of the Project Supervising Committee under the chairmanship of B. J. Clarke, Columbia Gas System Service Carp., M. A. Elliott, director, Institute of Gas Technology, and T. L. Robey and N. K. Chaney, American Gas Association, are gratefully acknowledged. Thanks are also due to E. J. Pyrcioch, who assisted in calculation and interpretation of the data, and to J. E. Neuzil and D. M. Mason, who supervised the analytical work. literature Cited Alberts, L. W., Bardin, J. S., Berry, D. W., Jones, H. R., Vidt, E. J., Chem. Eng. Progr. 48, 486-93 (1952). Am. SOC.Testing Materials, Philadelphia, “ASTM Standards of Coal and Coke,” Method D 271-48, September 1954. Austin, G. T., “High Temperature Hydrogenation of Coal,” Ph.D. thesis, Purdue University, 1943. Bray, J. L., Howard, R. E., “Hydrogenation of Coal at High Temperatures,” Rept. 1, Purdue Univ. Eng. Expt. Station, Lafayette, Ind., Research Ser. 90 (September 1943).
~I
RECEIVED for review May 31, 1957 ACCEPTED August 12, 1957 Division of Gas and Fuel Chemistry, 132nd Meeting, ACS, New York, N. Y . ,September 1957. Study conducted underjoint sponsorship of the Gas Operations Research Committee, American Gas Association, as part of its Promotion-Advertising-Research Plan and of the basic research program of the Institute of Gas Technology. ~~
Table V. Coal
Run No. Source Proximate analysis, wt. % Charge, grams Operating conditions Initial pressure, p.s.i.g. Hydrogen/coal ratio, SCF/lb. Threshold temp., O F. Time to reach threshold temp., min. Total time elapsed, min. Run time at temp., min. Reactor pressure, p.s.i.g. Reactor temp., F. Operating results Net B.t.u. recovery, MB.t.u./lb. Product gas yield, total SCF/lb. Gaseous hydrocarbon space-time yield, SCF/CF-hr.a Net moisture-, ash-free coal hydrogasified, wt. %b Material balance, % Product gas properties Gas composition,mole % ’ Nz+ CO
coz Hz
HzS
CHI CzHa C3Hs plus Olefins Benzene Toluene plus Total Heating value, B.t.u./SCF Specific gravity, air = 1
Operating Results for Hydrogasification of Low-Temperature Chars Bituminous Char Subbituminous Char 82
Pittsburgh Consolidation 0.9 moisture; 21.2 vol. matter; 6.2 ash
U. S. Bur. Mines 1.3 moisture; 19.3 vol. matter; 4.6 ash
60.0
60.0
90 0 2430 1350
1010 16.91 875 38 100 115 10 25 2430 2420 1350 1350
94
1010 16.83 745 31 104
0
10
2690 1350
85 U. 8. Bur. Mines 1.9 moisture; 25.2
vol. matter; 11.3 ash 60.0
2700 1350
119 25 2730 1350
100 0 3060 1350
1010 16.80 790 36 110 10 3090 1350
_ I _ _ _ -
140 50 2415 1350
125 25 3120 1350
0.862 11.97
4.820 11.97
5.100 11.92
4.914 11.90
4.963 13.23
5.224 13.28
5.421 13.42
6.083 15.04
6.298 15.19
6.273 15.33
14.9
36.1
29.7
22.7
34.0
30.0
26.9
38.3
33.7
28.0
13.1
37.7
39.9
38.1 98.2
41.9
42.5
46.3 102.2
46.3
47.7
47.7 98.5
1.5 0.3 71.6
2.5 0.3 20.2 0.1 75.5 0.7
2.9 0.3 17.9
2.7 0.2 17.1
5.2 1.6 26.7
5.2 1.3 25.7
5.3 2.5 19.6
5.4
5.6 0.8 26.2
6.5 1.1 25.7
... 65.0 2.7 0.2 0.1 2.4 2.0 0.2 ... ... 0.1 ... 0.1 ... 0.1 0.1 ... ... 0.1 0.7 ‘1.2 0.4 0.6 0.8 ..._ _ _0.1_ _ _..,_ _ _..._ _ ... __-_ _ _... ... 23.5
100.0 523 0.2333
100.0 854 0.4873
Based on time after reactor attained threshold temperature.
644
Lignite Char
84
INDUSTRIAL AND ENGINEERING CHEMISTRY
... 79.3
... 77.3
100.0 881 0.5118
... 63.5
...
71.6 0.4
. I .
0.6
...
100.0 100.0 100.0 100.0 867 782 798 804 0.4946 0.4846 0.4890 0.5185 wt. of product gas - wt. of hydrogen in 100 wt. of moisture-, ash-free charge
[
1.0
26.6 66.6
... 67.0
0.1
0.1
. . a
...
...
0.3
... ...
0.3
... 66.6
... ... ...
0.1
... -e . .
0 . .
100.0 761 0.4328
100.0 768 0.4393
100.0 759 0.4349
