liquefaction pathways of bituminous subbituminous coals andtheir

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COAL LIQUEFACTION USING DONOR SOLVENTS HYDROGENATED AT LOW TEMPERATURES* R.J. Kottenstette and H.P. Stephens Process Research Department 62 12 Sandia National Laboratories P.O. Box 5800 Albuquerque, NM 87185 Keywords: Hyrogen Donor, Coal Liquefaction, Solvent Quality Introduction Direct coal liquefaction proceeds initially through a complex series of bond breaking and hydrogen transfer reactions involving coal and a donor solvent. When the recycle solvent contains high amounts of donor solvent, the requirement for high hydrogen gas pressure in the initial stage of liquefaction is reduced and coal conversion is augmented. Effective tests for hydrogen donating ability of coal derived solvents often consist of GCMS, proton NMR, catalytic dehydrogenation, as well as microautoclave coal liquefaction testing [ 1,2,3]. Microautoclave testing is an empirical measure of solvent quality for hydrogen donation using coal, a donor solvent and an inert gas instead of hydrogen. Previous studies [4] have investigated the hydrogen transfer cycle for direct liquefaction using Illinois #6 high volatile bituminous coal and a distillate (650"F-770°F) derived from a coal liquefaction process solvent . The objective of this work is to determine the effects of donor solvent on coal conversions in microautoclave liquefaction experiments performed at 4OOOC with Wyodak coal. These tests used a heavy distillate solvent that had been hydrogenated with a synthesis gas (SO% carbon monoxide:SO% hydrogen) mixture and steam at low temperatures (3OO0C-325"C). The in situ water-gas shift (WGS) reaction provides an alternate source of hydrogen and has the potential of eliminating the need for high purity high pressure hydrogen for solvent hydrogenation. Hydrogenation at low temperatures can lead to increased donor content since larger amounts of hydroaromatics are produced at equilibrium with any given hydrogen pressure. Distillate solvents were hydrogenated at various weight hourly space velocities, using two different catalysts,and used in microautoclave coal liquefaction tests to evaluate solvent pretreatment effects on coal solubility. Experimental Materials - Because solvent quality is favorably affected by increasing the aromatic nature of the solvent being fed to the catalytic hydrotreater, and solvent dewaxing has been shown to be an effective means of increasing the aromatic nature of the solvent IS], a heavy distillate and a dewaxed heavy distillate were used. Heavy distillate sample (V1074) from the Wilsonville, Alabama Advanced Integrated Two Stage Liquefaction Facility was provided by CONSOL Inc., Library PA. Dewaxed VI074 distillate was prepared by CONSOL at - 5T from the VI074 heavy distillate using an acetone dewaxing procedure. 1,2,3,6,7,8 hexahydropyrene was purchased from Aldrich Chemical Company with a 99% purity. Reagent grade tetrahydrohran (THF), pentane, and heptane were purchased from Fischer Scientific. Wyodak subbituminous coal was used as -100 mesh from the Argonne Premium Coal Sample Bank. The NiMo catalyst, was Shell 324M and the platinum catalyst was a hydrous titanium oxide (HTO) compound synthesized in our lab. Hydrogen, carbon monoxide, and nitrogen were UHP grade. *This work was supported by the U. S. Department of Energy at Sandia National Laboratories under contract DE-AC04-76DP00789. 534
Apoaratus and Procedure Microflow Reactor Experiments - A fixed bed microflow reactor consisting of liquid and gas feed systems and a stainless steel reactor containing the catalyst bed (0.5" O.D.) was used to hydrogenate heavy distillate and dewaxed heavy distillate. The reactor had an internal volume of 23 cm3 and typically held a 20 gram catalyst'charge. These distillate pretreatment experiments consisted of three days of testing for each catalyst and feed combination. The first two days of experiments used the in situ water-gas shift reaction to hydrotreat the distillate. Reactions on the third day used solely hydrogen to test the effect of varying the partial pressure of hydrogen gas upon solvent hydrogen uptake. The reactor tube was first packed with catalyst and then presulfided with a 9% H2S in hydrogen mixture for four hours at 39OOC for the commercial nickel molybdenum on alumina catalyst (NIMo), or prereduced in hydrogen at 2OOOC for the platinum (Pt HTO) catalyst. After catalyst pretreatment, the reactor was pressurized to 1000 psig with a 5050 mixture of carbon monoxide and hydrogen. The reactor temperature was increased to the operating value while the distillate and a 1: 1:l molar mixture of CO:H2:H20 was fed the top of the reactor. Distillate was pumped into the reactor with an Eldex A-30 liquid chromatograph pump and the synthesis gas was metered into the reactor with two Brooks 5850 mass flow controllers. The liquid weight hourly space velocities were varied between 0.4 hrl and 0.8 hr-1. Water was fed to the reactor with a Beckman 114M microflow liquid chromatography pump. All reactants flowed downward over the packed bed into a reservoir to separate the gases and liquids. Solvent and gas products were taken from the sample reservoir at the bottom of the reactor during operation. Reactor pressure was maintained with a Circle Seal BPRz7A back pressure regulator, which was located downstream from the liquid separator. Distillates and hydrotreated distillates were also analyzed by high resolution gas chromatography using a Hewlett Packard 5890 GC to qualitatively measure hydrogenation of aromatic compounds. Microautoclave Experiments - Coal liquefaction tests were used to evaluate donor solvent quality. Hydrogenated solvent was tested in a microautoclave consisting of a 0.75" O.D. Swagelok tubing tee with 40 cm3 of gas volume. Pressure and temperature were measured in the microflow and batch microautoclave reactors with Entran pressure transducers and internal reactor thermocouples. Data acqusition for both the flow and batch reactor systems was accomplished with a personal computer using Labtech Notebook software. Coal and pretreated solvents representing various hydroprocessing conditions were weighed into the microautoclave reactor. The microautoclaves were sealed and pressurized with nitrogen to 100 psig cold charge to facilitate post reaction gas analysis. The pressurized microautoclaves were then fastened to a wrist-action shaker and immersed in a fluidized sand bath while being shaken at 200 cycles per minute. After a rapid heat up (< 2min.) the microautoclaves were maintained at 4OOOC for 30 minutes. Following reaction the microautoclaves were cooled to room temperature in water, then depressurized into gas sample bottles and dismantled to recover the reaction products. The gas samples were analyzed for hydrogen, carbon monoxide, carbon dioxide and c1-C~ hydrocarbons using a Carle series 400 Gas Chromatograph. Liquid and solids were recovered from the reactor with THF and the THF insolubles were determined by pressure filtration. The THF insolubles were dried and weighed while the THF solubles were rotoevaporated to remove most of the THF. Pentane was then added to these samples to precipitate the preasphaltendasphaltene material. These solutions were pressure filtered to remove the pentane insolubles. The pentane insolubles were then dried and weighed. 535
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 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: Figure 3. Minimum Steps to Explin D
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
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