General quantitative model for coal liquefaction kinetics: the thermal cleavage/hydrogen donor capping mechanism. [59 references]

Technical Report · Tue Jan 01 00:00:00 EST 1980

DOI:https://doi.org/10.2172/5531919· OSTI ID:5531919

Gangwer, T

A mechanism for coal liquefaction, based on the concept of thermal cleavage-hydrogen capping donor complexes, is proposed and the quantitative agreement between the derived rate laws and the kinetic data obtained from fifteen publications is presented. The mechanism provides rate laws which describe the preasphaltene, asphaltene, oil and gas time/yield curves for the coal liquefaction process. A simplistic dissolution model is presented and used to relate the proposed mechanism to the experimentally observed products. Based on the quality of the mechanistic fit to the reported coal liquefaction systems, which cover a diverse range of reaction conditions, coal types and donor solvent compositions, it is proposed that the donor solvent/thermal bond cleavage/hydrogen capping mechanism provides a good, quantitative description of the rate limiting process. Interpretation of the rate constant/temperature dependencies in terms of transition state theory indicates formation of the activated complex can involve either physically or chemically controlled steps. A uniform free energy of activation of 52 kcal was found for the diverse liquefaction systems indicating a common transition state describes the reactions. Thus the proposed mechanism unifies the diverse liquefaction kinetic data by using a set of uniform reaction sequences, which have a common transition state, to describe the conversion chemistry. The mechanism thereby creates a common base for intercomparison, interpretation and evaluation of coal conversion for the broad range of processes currently being investigated in the liquefaction field.

• Research Organization: Brookhaven National Lab. (BNL), Upton, NY (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: EY-76-C-02-0016
• OSTI ID: 5531919
• Report Number(s): BNL-27279
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
COAL LIQUEFACTION
CHEMICAL REACTION KINETICS
MATHEMATICAL MODELS
ACTIVATION ENERGY
ARRHENIUS EQUATION
CHEMICAL BONDS
CHEMISTRY
CLEAVAGE
CONSUMPTION RATES
CORRELATIONS
DISSOLUTION
GRAPHS
HYDROGEN
HYDROGEN TRANSFER
NUMERICAL DATA
RADICALS
TABLES
TIME DEPENDENCE
CRYOGENIC FLUIDS
CRYSTAL STRUCTURE
DATA
DATA FORMS
ELEMENTS
ENERGY
FLUIDS
INFORMATION
KINETICS
LIQUEFACTION
MICROSTRUCTURE
NONMETALS
REACTION KINETICS
THERMOCHEMICAL PROCESSES
010405* - Coal
Lignite
& Peat- Hydrogenation & Liquefaction
400300 - Organic Chemistry- (-1987)