Fundamental Kinetics of Supercritical Coal Liquefaction: Effect of Catalysts and Hydrogen-Donor Solvents

Technical Report · Wed Apr 16 04:00:00 EDT 1997

DOI:https://doi.org/10.2172/2029· OSTI ID:2029

McCoy, Ben J ^[1]; Madras, Girodhar; Smith, J M; Kodera, Yoichi

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1. Federal Energy Technology Center

This is the quarterly report on our recent progress toward the overall objective to understand the supercritical fluid extraction of hydrocarbons from coal. Our strategy is to simulate coal as a high molecular-weight polymeric material by studying the degradation of polymers under various conditions. The hypothesis we are testing is that degradation of such macromolecules is applicable to the decomposition (depolymerization) of the coal network. Polymer degradation and coal liquefaction are influenced strongly by the solvent in the reaction. This motivated our investigation of the effect of hydrogen donor solvents on polymer degradation. In particular, we obtained new experimental data to show how a hydrogen donor, 6-hydroxy tetralin, influences the degradation rate of polystyrene. We also developed a detailed radical mechanism for hydrogen donation based on the Rice-Herzfeld chain reaction concept with the elementary steps of initiation, depropagation, hydrogen abstraction, and termination. Expressions for the degradation rate parameters were obtained by applying continuous distribution kinetics to the MWD of the reacting polymer. The theory explains the different influences of the hydrogen donor solvent on the degradation rate coefficients for different polymers. Though developed for the degradation of polymers, the mechanism and the theory are potentially applicable for chain scission and addition reactions among distributions of paraffins, olefins, and radicals of all chain lengths. The concepts can, in principle, be extended to examine the effect of hydrogen donors on coal liquefaction and on the complex mixture of liquefaction compounds. Based on this work, a research paper titled "Effect of Hydrogen Donors on Polymer Degradation", has been submitted for publication. Our research paper entitled, "Molecular weight effect on the dynamics of polystyrene degradation", has been accepted for publication by the journal, Industrial and Engineering Chemistry Research.

• Research Organization: Federal Energy Technology Center, Morgantown, WV, and Pittsburgh, PA
• Sponsoring Organization: USDOE
• DOE Contract Number: FG22-94PC94204
• OSTI ID: 2029
• Report Number(s): DE-FG22-94PC94204--10; ON: DE00002029
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
Coal Liquefaction
Reaction Kinetics
Solvents