liquefaction pathways of bituminous subbituminous coals andtheir

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somewhat higher t h comparable shake-flask tests for both types of coal without HCI treatment.l Thus, the fluidized bed appears to be a more efficient contacting system. One test was made with bituminous coal in pyridine in which the solvent containing DNP-mixed enzymes was replaced after 4 and 8 h in order to determine whether appreciable interaction could be induced throughout the course of the 24-h run. This was apparently the case since there was a significant increase in absorbance at 376 nm throughout a greater portion of the 24-h test. Apparent coal conversion without acid leaching of the residue to remove precipitated enzymes was 35.3%. This is the largest amount of biocatalyzed liquefactiodsolubilization of a higher-rank coal that has been observed; it is a threefold increase over the fluidized-bed test in which there was a single charge of the solvent mixture. Fluorescence Visualization of Coal Particles in a Fluidized Bed Effective modeling, design and implementation of fluidized-bed reactors rely upon knowledge of bed expansion and segregation tendencies with particles of varying size and density. We have recently introduced a fluorescence method for the visualization of coal particles within a fluidized bed-reactor.* In this method, the dye fluorescein is added to the liquid phase and serves as a contrast agent. A modified fluorescence microscope abuts the column and is used to image the fluorescence emission in response to epi-illumination. The resulting image (dark particles on a bright field of fluorescent liquid) may be digitized and analyzed by using edge-detection algorithms to provide particle-area fraction and size distributions. The microscope may be positioned at any height relative to the column, thus producing particle segregation and expansion statistics as a hnction of bed height. Unlike previous attempts to visualize segregation in fluidized beds which require direct sampling, use of a modified ultra-thin column, low particle volume fraction, or radiation, the proposed method is non-invasive and may be conducted in an operational reactor at standard flow rates and particle loading. Further, unlike our previous attempts to directly label a bimodal distribution of coal particles,* the current method may be applied to any distribution of particle sizes and densities, without possible alteration of particle hydrodynamics. Preliminary results have been obtained on a small (I-A) column in which a bimodal distribution (53-63 and 150-250 pm) of coal was fluidized. Digitized images clearly show that particle segregation is occurring and that both large and small particles are present throughout the column. Figure 1 demonstrates the current abilities in bed visualization. Figure la is a view near the top of the column while Figure Ib displays conditions near the bottom. In these figures, the round, darker regions are coal particles fluidized by fluoresceidwater. Even from these preliminary data, it is evident that more large particles reside at the bottom of the column. Digital filtering and edge-detection algorithms have been developed to convert such images into particle area fraction and size distribution data as a function of axial position. These data will be of use in the development of predictive mathematical models of bed expansion and segregation), and will also be usehl in assessing the accuracy of current models. 636
Conclusions Reducing enzymes can be chemically modified by the addition of dinitrophenyl groups so that they will be soluble in organic solvents while still maintaining biocatalytic activity. A hydrogenase has been shown to enhance the liquefactiod solubilization of bituminous and lignite coals in both pyridine and benzene at 30°C when a reducing reagent such as reduced cytochrome c and/or molecular H2 is used. A less polar organic solvent such as benzene may be more effective, and a small fluidized-bed has been shown to be an efficient contactor, especially with sequential addition of the reaction liquids. Coal conversions of up to 35.3% have been observed. A fluorescence method has been introduced to enable the visualization of coal-particle segregation and degradation in a fluidized bed-reactor. This technique will greatly enhance the ability to design and efficiently utilize this reactor scheme. Acknowledgments Research supported by the Fossil Energy Advanced Research and Technology Program, managed in part by the Pittsburgh Energy Technology Center, U.S. Department of Energy, under contract DE-AC05-840R21400 with Martin Marietta Energy Systems, Inc. “The submitted manuscript has been authored by a contractor of the U.S. Government under contract DE-AC05-840R21400. Accordingly, the U.S. Government retains a nonexclusive, royalty-free license to publish or reproduce the published form of this contribution, or allow others to do so, for U.S. Government purposes.” REFERENCES Scott, C. D., Scott, T. C. and Woodward, C. A,, Fuel. In Press Kaufman, E. N. and Scott, T. C., Powder Technology. Submitted for Publication Asif, M., Petersen, J. N., Scott, T. C. and Cosgrove, J. M., Fuel. In Press. Scott, C. D., Faison, B. D., Woodward, C. A,, and Brunson, R. R. in “Proceedings: 1991 Second International Symposium on the Biological Processing ofcoal,” (Ed. S. Yunker), Electric Power Research Institute, Palo Alto, CA, 1991, pp. 4-29 - 4-39. Sanger, F. Biochem. J. 1945.39, 507 Sanger, F. Biochem. J. 1949,45, 563 Scott, C. D., Scott, T. C., and Woodward, C. A. Appl. Biochem. Biotechnol. In Press. Scott, T. C., Cosgrove, J. M., Asif, M. and Petersen, J. N., Fuel. In Press. 637
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LIQUEFACTION PATHWAYS OF BITUMINOUS
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the conversion of A+P and O+G with
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Asphaltcncs PrCasphaltenCS Cwr%, da
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NEW DIRECTIONS TO PRECONVERSION PRO
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ecause of incorporation of the coal
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should be considered more. The step
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17 18 Run no. 0 cys I ToS-CyS TS-To
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INTRODUCTION Effects of Thermal and
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apid decline in modulus. The loss m
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-0.01- . 04 5 -0.03- E 6 -0.0s- c)
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Assessment of Small Particle Iron O
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yields are calculated by subtractin
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conversion is greater than the corr
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Table 3. Effect of Superfine Iron O
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EFFECT OF A CATALYST ON THE DISSOLU
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inherent volatility of Mo(CO), perm
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Analysis of the quantity and compos
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$ EO .- 0 m L 0 c 0 0 > 40 300 350
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0 0 0 0 0.000 0.005 0.010 0.015 0.0
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of these studies indicate that cont
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Different levels of adsorption occu
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Nominal 2 Table 1. Concentration of
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- iF m 1.6 1.4 1.2 - - - 1- 0 0.8 -
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RESULTS AND DISCUSSION Swelling of
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. . % . . 9 'HF 0 0 0 *. . 0 . . 0
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1.50 KQ 1.00 0.50 I / ' 02 525 I 1
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hydrogen atoms. The hydrogen atoms
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D to generate more D atoms. It is r
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12. a. Poutsma, M. L.; Dyer, C. W.
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Figure 3. Minimum Steps to Explin D
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Apoaratus and Procedure Microflow R
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Model ComDound Test Figure 5 shows
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Figure 1. High resolution gas chrom
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Figure 5. Product distribution for
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THQ at somewhat higher temperatures
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areas of the particles and the SEM
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Experimental Catalyst Precursors an
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impregnating solvent. Table 3 shows
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of MoCo-TC2 at the level of 0.5 wt%
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Table 4. Effect of Temperature Prog
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In the past, chemical treatments in
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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
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same conditions and an extraction t
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ACKNOWLEDGEMENT The authors thank t
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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
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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
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Table 1. F'yrolysis Results of Vacu
Page 111 and 112: 585 I
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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
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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: Results Enzyme Modification with Di
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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