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Title: Mechanisms and kinetics of coal hydrogenation

Abstract

Colorado School of Mines is engaged in an experimental program to develop comprehensive models for the effects of coal composition upon the kinetics and mechanisms of coal hydrogenation, for the effects of mineral matter additives (disposable catalysts) upon kinetics and mechanisms of coal hydrogenation, and for the kinetics and mechanisms of the hydrogenation of coal derived products such as preasphaltenes, and asphaltenes. Experimental data collection in the area of coal reactivity has continued. Approximately one-half of the suite of bituminous coals chosen for study has been run, and kinetic modeling has been initiated. Analysis of the data from runs made to date indicates that coal conversion may be adequately modeled by a pseudo-second-order rate expression, and that the model is sufficient to differentiate between coal reactivities. Baseline runs have been completed on the disposable catalyst study and a limited number of mineral matter additive runs using pyrite, pyrrhotite, moly ore, and MoS/sub 2/ have been made.

Authors:
; ;
Publication Date:
Research Org.:
Colorado School of Mines, Golden (USA). Dept. of Chemical and Petroleum Refining Engineering
OSTI Identifier:
6813293
Alternate Identifier(s):
OSTI ID: 6813293
Report Number(s):
DOE/ET/14881-3
DOE Contract Number:
AC22-79ET14881
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; ASPHALTENES; HYDROGENATION; COAL; CATALYSTS; MINERALS; CATALYTIC EFFECTS; CHEMICAL REACTION KINETICS; EXPERIMENTAL DATA; MOLYBDENUM SULFIDES; PYRITE; PYRRHOTITE; ASPHALTS; BITUMENS; CARBONACEOUS MATERIALS; CHALCOGENIDES; CHEMICAL REACTIONS; DATA; ENERGY SOURCES; FOSSIL FUELS; FUELS; INFORMATION; IRON COMPOUNDS; IRON SULFIDES; KINETICS; MATERIALS; MOLYBDENUM COMPOUNDS; NUMERICAL DATA; ORES; ORGANIC COMPOUNDS; OTHER ORGANIC COMPOUNDS; PYRITES; REACTION KINETICS; SULFIDES; SULFUR COMPOUNDS; SULFUR ORES; TAR; TRANSITION ELEMENT COMPOUNDS 010403* -- Coal & Coal Products-- Hydrogenation-- (-1987)

Citation Formats

Gary, J H, Baldwin, R M, and Bain, R L. Mechanisms and kinetics of coal hydrogenation. United States: N. p., 1980. Web. doi:10.2172/6813293.
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Gary, J H, Baldwin, R M, & Bain, R L. Mechanisms and kinetics of coal hydrogenation. United States. doi:10.2172/6813293.
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Gary, J H, Baldwin, R M, and Bain, R L. Wed . "Mechanisms and kinetics of coal hydrogenation". United States. doi:10.2172/6813293. https://www.osti.gov/servlets/purl/6813293.
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@article{osti_6813293,
title = {Mechanisms and kinetics of coal hydrogenation},
author = {Gary, J H and Baldwin, R M and Bain, R L},
abstractNote = {Colorado School of Mines is engaged in an experimental program to develop comprehensive models for the effects of coal composition upon the kinetics and mechanisms of coal hydrogenation, for the effects of mineral matter additives (disposable catalysts) upon kinetics and mechanisms of coal hydrogenation, and for the kinetics and mechanisms of the hydrogenation of coal derived products such as preasphaltenes, and asphaltenes. Experimental data collection in the area of coal reactivity has continued. Approximately one-half of the suite of bituminous coals chosen for study has been run, and kinetic modeling has been initiated. Analysis of the data from runs made to date indicates that coal conversion may be adequately modeled by a pseudo-second-order rate expression, and that the model is sufficient to differentiate between coal reactivities. Baseline runs have been completed on the disposable catalyst study and a limited number of mineral matter additive runs using pyrite, pyrrhotite, moly ore, and MoS/sub 2/ have been made.},
doi = {10.2172/6813293},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Oct 01 00:00:00 EDT 1980},
month = {Wed Oct 01 00:00:00 EDT 1980}
}
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Technical Report:
View Technical Report (2.06 MB)
DOI:  10.2172/6813293
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  • ; ; ; ...
    Colorado School of Mines is engaged in an experimental program to develop comprehensive models for the effects of coal composition upon the kinetics and mechanisms of coal hydrogenation, for the effects of mineral matter additives (disposable catalysts) upon kinetics and mechanisms of coal hydrogenation, and for the kinetics and mechanisms of the hydrogenation of coal-derived products such as preasphaltenes and asphaltenes. Safety modifications to the CSM continuous processing unit were completed to shield the control room from the gas and liquid-solid product sampling systems. A mass balance analysis of sample validity was begun. All but two of sixteen coals inmore » the suite of coal reactivity study coals have been run. Computer modelling of proposed reaction networks was started. Initial efforts at coal property versus reactivity correlations were begun. Feed material preparation for the asphaltene hydrogenation study was completed, and preliminary testing of the reactor system was begun. The experimental portion of the disposable catalyst study screening program was completed. Conclusions are pending statistical analyses of the data.« less

  • ; ;
    The objective of this task is to utilize the continuous-flow bench-scale coal liquefaction reactor system at CSM to investigate the rate of reaction of different coals at different processing conditions. Particularly, reaction rates at short residence times are to be measured in a Continuous Flow Stirred Tank Reactor (CSTR), and this information used to model reactions in the Plug Flow Reactor (PFR) section of the unit. Work during the past 6 months has focused on completing modifications to the unit itself, as the bench-scale system was originally designed to be operated at residence times just under 30 minutes. The newmore » residence times are to be, at the least, just less than 6 minutes. The experimental portion will be a comparative study of the effect of different processing conditions on the rate of coal liquefaction. During the past six months, work on the continuous unit has been confined to modifications and system tune-up.« less

  • ; ;
    Colorado School of Mines is conducting coal hydrogenation research with the following objectives and scope of work: (1) Comparison of the rates of coal hydrogenation in continuous flow stirred tank and tube flow reactors using pure hydrogen, catalyzed CO-STEAM, and syngas processing conditions; (2) Investigation of the influence of coal rank on the rate of hydrogenation of coal to preasphaltene, asphaltenes, and oil in batch reactors; (3) Batch evaluation of the effect of operating conditions (temperature and pressure) on the rate of hydrogenation of coal-derived preasphaltanes and asphaltenes; (4) Determination of the effect of selected disposable catalysts on the ratemore » of batch hydrogenation of preasphaltenes and asphaltenes and selected bituminous coals. Testing and evaluation of promising catalyst systems in the contunuous processing unit; (5) Formulation of a unified kinetic/mechanistic model for coal liquefaction taking into account petrography of the feed coal and hydrocarbon lumps in the product oil.« less

  • When pyrite alone (2g) was employed as the additive, total conversion results were found to be comparable to the case with 2% H/sub 2/S and no added pyrite. The increase in conversion at short residence time was again reflected most strongly in the presphaltene fraction. Gas analyses on the reaction products after cool-down showed that H/sub 2/S levels were about 0.03% when pyrite alone was the additive, and 0.3% when 2% H/sub 2/S was the additive. No H/sub 2/S was present in the reactor product gas for the baseline runs (no additives). The effect noted upon addition of pyrite thusmore » may be explained by two entirely different catalytic mechanisms: (1) a heterogeneous catalytic mechanism involving catalysis promoted by reduced pyrite; (2) a homogeneous catalytic mechanism involving catalysis of hydrogen transfer by H/sub 2/S released from the hydrogenated pyrite. Pyrite reduction to iron sulfide has previously been shown to be very rapid at the temperatures employed in this study (Gertenback et al., 1979). A synergistic effect seems to be present when both H/sub 2/S and pyrite are added to the reactor, as evidenced by the significantly reduced preasphaltene content and enhanced oil yield as the H/sub 2/S content is increased in the presence of added pyrite. This may reflect maintenance of the catalytically active iron sulfide species in the reactor, or simply reflect increased hydrogen transfer catalysis by H/sub 2/S. Although reduced iron pyrite has been purported by many researchers to be a catalyst responsible for enhanced reactivity of coal towards liquefaction, it is difficult to see how a substance with such a low surface area (<2 m/sup 2//g) can function efficiently as a hydrogenation catalyst.« less

  • Data for coal hydrogenation in the presence of added H/sub 2/S, pyrite, and H/sub 2/S + pyrite are shown in Table 15 along with baseline data for hydrogenation without the use of additives. What is perhaps most striking about these data is the influence of added H/sub 2/S in absence of added pyrite. The percentages of H/sub 2/S refer to the mole % H/sub 2/S in the gas atmosphere prior to heating and reaction (cold composition). A 56% increase in overall conversion is indicated at the 10 minute residence time, with a 21% increase at 60 minutes when gaseous H/submore » 2/S alone is added to the reaction gas atmosphere. The predominate influence on product distribution is in the preasphaltene fraction, especially at the short residence time. Clearly, H/sub 2/S is acting as a catalyst for coal liquefaction at these conditions. Concentrations above 2% H/sub 2/S in the initial gas phase mixture do not seem to appreciably increase the conversion; the effect noted at 60 minutes between 5% and 10% may not be significant due to scatter in the data. The function of H/sub 2/S in this case may be as either a homogeneous or heterogeneous catalyst. Rebick has reported a catalytic effect of H/sub 2/S on a n-hexadecane pyrolysis, and attributed the noted effect to catalysis of hydrogen transfer. Since the early stages of coal liquefaction are thought to proceed via free radical chemistry, a similar effect may be operative here.« less