liquefaction pathways of bituminous subbituminous coals andtheir

More documents

Recommendations

Info

Asphaltcoca + Prcas haltcoca (WL %, daff Oils t Gases 20 40 60 80 IOM (wt. 46, dan (wt. 46, dafl Figure 4. Thermal and catalytic pathway of a Wyodak coal (0, thermal; 0, Fe,O,; A, molybdenum naphthenate). Asphaltencs Oils + Oases 20 40 ,60 80 Prcasphaltcnes + IOM Figure 5. Thermal pathway of bltumlnous coal-derlved asphaltenes (A), preasphaltenes (P) and a 50/50 wt.% mixture of asphaltenes and preasphaltenes (M). 480
NEW DIRECTIONS TO PRECONVERSION PROCESSING OF COAL M. Nishioka, W. Laird, P. Bendale, and R A. Zeli V i g Systems International, 2070 Wdiam pitr Way, Piinburgh, PA 15238 Keywords: Coal Liquefaction, High-Temperature Soaking, Coal Associations INTRODUCTION Coal structure should be well understood for the effective development of coal liquefaction. A cross-linked three-dimensional macromolecular model has been widely accepted for the structure of coal. Coal liquefaction is being developed based on this model. Recent studies, however, showed that significant portions (far more than generally believed) of coal molecules are physically associated'. If physical association is dominant, all properties and reactivities in coal liquefaction must be a strong function of intra- and intermolecular (secondary) interactions and molecular weight. It is necessary to reinvestigate a coal conversion procedure based on the associated nature of coal. Many efforts of chemical pretreatments have been made to cleave chemical bonds by using reagents or high pressure of CO and H,O etc. Coal changes molecular conformations during soaking/dissolution steps due to relatively strong secondary interactions. This may lead to decrease in dissolution, but this phenomena have often been regarded as retrograde reactions. The stabilization of radical intermediate has been considered to prevent retrograde reactions. These concepts of selective bond cleavages and prevention of retrograde reactions are based on the network model. If a large portion of coal is associated, coal may be dissolved to a great degree. It is expected that largely dissolved coal can easily be converted to liquid. However, dissolution has not been an easy task, as shown by many researchers for a long time. If coaVcoal complexes with high molecular weight are replaced with molecules with low molecular weight, coal may be dissolved to more extent. Associated coal is regarded as material with broad molecular weight distribution. Reactivity of these material may be different. Fractions with different molecular weight may be treated separately to produce desired fractions, if possible. These are the major features considered in this paper based on the associated molecular nature of coal. In this paper, a new concept of coal preconversion is shown on the basis of these propositions. Two subjects are focused on: (1) maximizing dissolution of associated coal without additional chemicals and (2) step-wise conversion of associated coal with broad molecular weight distribution. For these purposes, the following procedure has been tested two-step soaking at 35O-WC, followed by isolation of oil, and then liquefaction of residue. This enabled to lower liquefaction severity, to decrease the gas yield, and to increase the oil yield. Some of these results and the future perspective of two-stage liquefaction will be discussed. EXPERIMENTAL Coal samples were obtained from the DOE Coal Bank at Pennsylvania State University. 481
Page 1 and 2: LIQUEFACTION PATHWAYS OF BITUMINOUS
Page 3 and 4: the conversion of A+P and O+G with
Page 5: Asphaltcncs PrCasphaltenCS Cwr%, da
Page 9 and 10: ecause of incorporation of the coal
Page 11 and 12: should be considered more. The step
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
Page 85 and 86:
Reaction Time Figure 1 - Schematic
Page 87 and 88:
DISSOLUTION OF THE ARGONNE PREMIUM
Page 89 and 90:
A much more def~tive trend is seen
Page 91 and 92:
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
Page 99 and 100:
to be originally derived from demet
Page 101 and 102:
145 30 I --/---Jh I , , I I , 250 2
Page 103 and 104:
THE EFFECTS OF MOISTURE AND CATIONS
Page 105 and 106:
1 for the Zap lignite. These result
Page 107 and 108:
content of the samples ion-exchange
Page 109 and 110:
Table 1. F'yrolysis Results of Vacu
Page 111 and 112:
585 I
Page 113 and 114:
EFFECT OF TEMPERATURE, SAMPLE SI2E
Page 115 and 116:
of some of the thermobalance runs.
Page 117 and 118:
2. The mechanism of drying is a uni
Page 119 and 120:
Influence of Drying and Oxidation 0
Page 121 and 122:
"c gives W conversion mpared to the
Page 123 and 124:
Table 1. Products dismbutions (dmmf
Page 125 and 126:
- 50 45 40 E 35 2 30 E T) 25 ap 20
Page 127 and 128:
Influence of Drying and Oxidation o
Page 129 and 130:
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
Page 139 and 140:
of the ronl roniponcnte nnd (2) the
Page 141 and 142:
2w 180 160 9 140 120 P loo f 80 P O
Page 143 and 144:
25 I 20 ' + 0 Drying lime, hours Fi
Page 145 and 146:
substructure have been identified a
Page 147 and 148:
Pyridine extraction showed that 60
Page 149 and 150:
Figure 1. Reflected white-light pho
Page 151 and 152:
Table 3. Pyridine Extraction Sample
Page 153 and 154:
A bang-bang control strategy was us
Page 155 and 156:
increased from 120°C to 135”C, r
Page 157 and 158:
* wt% based on the amount of naphth
Page 159 and 160:
Use of Biocatalysts for the Solubil
Page 161 and 162:
Results Enzyme Modification with Di
Page 163 and 164:
Conclusions Reducing enzymes can be
Page 165 and 166:
Dynamics of the Extract Molecular-W
Page 167 and 168:
where yi = (x-xi !/pi. The zero mom
Page 169 and 170:
satisfactory agreement between theo
Page 171 and 172:
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
Page 177 and 178:
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
show all

liquefaction pathways of bituminous subbituminous coals andtheir

Create successful ePaper yourself

Delete template?

Save as template?