liquefaction pathways of bituminous subbituminous coals andtheir

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I been reviewed and studied''. The dissolution and hydrogen consumption rates of a pyridine extracted coal and a whole coal were similar for West Kentucky coal (80% carbon, daf)". Whereas, a significant decrease in liquefaction conversions was observed when a coal was extracted with pyridine for Illinois no. 6 coal". Waninski and Holder" found the retrogressive behavior in conversion for pyridine extract part of Illinois no. 6 coal. Although it is difficult to conclude the effect of the soluble and insoluble components fmm these results, it seems that the reactivity of residues or high molecular weight components is not so poor as that of low molecular weight components. The assmiutd molecular nature and liipefactwn It was shown that a large portion of coal can be dissolved by the high-temperature soaking in the coal liquid, and the programmed or step-wise heating is preferred to enhance an oil yield. The highly dissolved coal was liquefied to a larger extent. Further, it was suggested that coal with a broad molecular weight distribution should be separated into an oil fraction after dissolution, and that only residue should be liquefied at the following step. From these results, a new concept is proposed to increase an oil yield and decrease a gas yield as shown in the block diagram (Figure 4). Coal is soaked in a recycle oil at 350°C and at 400°C. Gas and oil are recovered by vacuum distillation, and the bottom fraction is fed to a liquefaction section and liquefied under low pressure hydrogen at a relatively low temperature. The proposed procedure was tested using an autoclave. The DECS-2 coal was soaked in the coal liquid under nitrogen at 350°C and at 400°C for 1 h, respectively. The oil fraction was extracted with cyclohexane, and the cyclohexane insoluble portion was liquefied under low pressure of hydrogen (2.8 MPa) at 430°C for 1 h (Run 20). For comparison, the coal was soaked in the coal liquid at 200°C for 1 h, and then the mixture was liquefied under the same condition for 2 h (Run 19). In these Runs, gas yields were analyzed. Figure 5 shows these results. It is notable that the CyS (or oil) yield increased 30% and the gas yield decreased 15%. DECS-8 (subbituminous) coal was also examined with the same procedure. As the ionic forces are relatively strong and abundant in low rank coals', it is an important step to weaken the ionic forces before the high-temperature soaking. Although it has been known that acid washing enhances the conversion of low rank the details on acid washing have not clearly been explained. Here, 2N HCl washin2 was used to weaken the ionic forces in the coal before the high-temperature soaking. The coal was soaked in the coal liquid at 35OOC and at 400°C for 1 h, respectively. Cyclohexane insolubles from the soaked coal was similarly liquefied at 430°C for 1 h (Run 22). As the acid washed coal was dried, the dried DECS-8 coal was soaked at 200°C for 1 h and then liquefied at 430°C for 2 h for comparison (Run 21). Again, more than 30% increase in the oil yield and 20% decrease in the gas yield was observed by the procedure (Figure 5). CONCLUSIONS An improved coal liquefaction concept was reinvestigated for the current two-stage process on the basis of the associated molecular nature of coal. Since a significant portion of coal molecules are physically associated as pointed in our recent paper, physical dissolution 484
should be considered more. The step-wise high-temperature soaking was a simple and effective method for coal dissolution. Larger dissolution made liquefaction severity lower. Broad molecular weight distribution in the associated coal was another important factor. The selective reaction of fractions with high molecular weight which were isolated after the high-temperature soaking made gas yield lower. Tests with using an autoclave by the concept shown in Figure 5 enabled to produce 30% more oil and 1520% less gas yields. It is expected that the procedure will result in great cost down in coal liquefaction. ACKNOWLEDGEMENT This work was supported by the U.S. Department of Energy under Contract DEAC22- 91Pc91041. REFERENCES 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Nishioka, M. Fuel 1992,71,941 Nishioka, M., Gebhard, L. and Silbernagel, B. G. Fuel 1991, 70, 341 Gollakota, S. V., Lee, J. M. and Davies, 0. Fuel Roc. Tech. 1989, 22, 205 Wham, R. M. Fuel 1987,66,283 Joseph, J. T. Fuel 1991, 70, 139 Joseph, J. T. Fuel 1991, 70,459 Nishioka, M., Laird, W. and Bendale, P. Fuel submitted Nishioka, M. and Laird, W. Fuel submitted Song, C., Schobert, H. H. and Hatcher, P. G. Energv & Fueh 1992, 6, 328 Waninski, R. P. and Holder, G. D. Fuel 1992, 71, 993 Whitehurst, D. D., Farcasiu, M., Mitchell, T. 0. and Dickert, J. J. Jr. Electric Power Research Institute Report EPRI AF-480, Palo Alto, CA, 1077, pp. 74-7-10 Seth, M. PhD Thesis University of California Berkeley, Berkeley, CA, 1980 Schafer, H. N. S. Fuel 1970,49, 197 Mochida, I., Shimohara, T., Korai, Y., Fujitsu, H. and Takeshita, K Fuel 1983, 62, 659 %no, M. A, Solomon, P. R., Kroo, E., Bassilakis, R., Malhotra, R. and McMillen, D. Am. Chem. Soc. Div. Fuel Chon. Repr. 1990,35(1), 61 Joseph, J. T. and Rorrai, T. R. Fuel 1992, 71, 75 485
Page 1 and 2: LIQUEFACTION PATHWAYS OF BITUMINOUS
Page 3 and 4: the conversion of A+P and O+G with
Page 5 and 6: Asphaltcncs PrCasphaltenCS Cwr%, da
Page 7 and 8: NEW DIRECTIONS TO PRECONVERSION PRO
Page 9: ecause of incorporation of the coal
Page 13 and 14: 17 18 Run no. 0 cys I ToS-CyS TS-To
Page 15 and 16: INTRODUCTION Effects of Thermal and
Page 17 and 18: apid decline in modulus. The loss m
Page 19 and 20: -0.01- . 04 5 -0.03- E 6 -0.0s- c)
Page 21 and 22: Assessment of Small Particle Iron O
Page 23 and 24: yields are calculated by subtractin
Page 25 and 26: conversion is greater than the corr
Page 27 and 28: Table 3. Effect of Superfine Iron O
Page 29 and 30: EFFECT OF A CATALYST ON THE DISSOLU
Page 31 and 32: inherent volatility of Mo(CO), perm
Page 33 and 34: Analysis of the quantity and compos
Page 35 and 36: $ EO .- 0 m L 0 c 0 0 > 40 300 350
Page 37 and 38: 0 0 0 0 0.000 0.005 0.010 0.015 0.0
Page 39 and 40: of these studies indicate that cont
Page 41 and 42: Different levels of adsorption occu
Page 43 and 44: Nominal 2 Table 1. Concentration of
Page 45 and 46: - iF m 1.6 1.4 1.2 - - - 1- 0 0.8 -
Page 47 and 48: RESULTS AND DISCUSSION Swelling of
Page 49 and 50: . . % . . 9 'HF 0 0 0 *. . 0 . . 0
Page 51 and 52: 1.50 KQ 1.00 0.50 I / ' 02 525 I 1
Page 53 and 54: hydrogen atoms. The hydrogen atoms
Page 55 and 56: D to generate more D atoms. It is r
Page 57 and 58: 12. a. Poutsma, M. L.; Dyer, C. W.
Page 59 and 60: Figure 3. Minimum Steps to Explin D
Page 61 and 62:
Apoaratus and Procedure Microflow R
Page 63 and 64:
Model ComDound Test Figure 5 shows
Page 65 and 66:
Figure 1. High resolution gas chrom
Page 67 and 68:
Figure 5. Product distribution for
Page 69 and 70:
THQ at somewhat higher temperatures
Page 71 and 72:
areas of the particles and the SEM
Page 73 and 74:
Experimental Catalyst Precursors an
Page 75 and 76:
impregnating solvent. Table 3 shows
Page 77 and 78:
of MoCo-TC2 at the level of 0.5 wt%
Page 79 and 80:
Table 4. Effect of Temperature Prog
Page 81 and 82:
In the past, chemical treatments in
Page 83 and 84:
The effect of Corn20 preaatment on
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Reaction Time Figure 1 - Schematic
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DISSOLUTION OF THE ARGONNE PREMIUM
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A much more def~tive trend is seen
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EFFECT OF CHLOROBENZENE TREATMENT O
Page 93 and 94:
same conditions and an extraction t
Page 95 and 96:
ACKNOWLEDGEMENT The authors thank t
Page 97 and 98:
THE STRUCTURAL &=RATION OF HUMINlTE
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to be originally derived from demet
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145 30 I --/---Jh I , , I I , 250 2
Page 103 and 104:
THE EFFECTS OF MOISTURE AND CATIONS
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1 for the Zap lignite. These result
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content of the samples ion-exchange
Page 109 and 110:
Table 1. F'yrolysis Results of Vacu
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585 I
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EFFECT OF TEMPERATURE, SAMPLE SI2E
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of some of the thermobalance runs.
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2. The mechanism of drying is a uni
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Influence of Drying and Oxidation 0
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"c gives W conversion mpared to the
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Table 1. Products dismbutions (dmmf
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- 50 45 40 E 35 2 30 E T) 25 ap 20
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Influence of Drying and Oxidation o
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FTIR . . of the L m To investigate
Page 131 and 132:
CONCLUSIONS The characexizntion of
Page 133 and 134:
A b S 0 r b a n C e A b s 0 r b a n
Page 135 and 136:
An NMR Investigation of the Effd of
Page 137 and 138:
for determining the area of the pea
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of the ronl roniponcnte nnd (2) the
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2w 180 160 9 140 120 P loo f 80 P O
Page 143 and 144:
25 I 20 ' + 0 Drying lime, hours Fi
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substructure have been identified a
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Pyridine extraction showed that 60
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Figure 1. Reflected white-light pho
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Table 3. Pyridine Extraction Sample
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A bang-bang control strategy was us
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increased from 120°C to 135”C, r
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* wt% based on the amount of naphth
Page 159 and 160:
Use of Biocatalysts for the Solubil
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Results Enzyme Modification with Di
Page 163 and 164:
Conclusions Reducing enzymes can be
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Dynamics of the Extract Molecular-W
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where yi = (x-xi !/pi. The zero mom
Page 169 and 170:
satisfactory agreement between theo
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0.8 0.6 0.4 0.2 “E \ bo Y, - 1 0
Page 173 and 174:
The Use of Solid State C-13 NMR Spe
Page 175 and 176:
differences lie in the fact that th
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I- z W 0 K W n PROTONATED AROMATIC
Page 179 and 180:
ZAP WIO SIDE CHAINS IN PYRIDINE EXT
Page 181 and 182:
ORGAFlIC VOLATILE MATER AND ITS SUL
Page 183 and 184:
(Figure 1). They indicated that the
Page 185 and 186:
Table 3. Elemental analysis of arom
Page 187:
1- 700'C Figure 3. GClFID chromatog
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