Chemical kinetics and transport processes in supercritical fluid extraction of coal. Final report, August 10, 1990--December 30, 1992

Technical Report · Mon Feb 01 04:00:00 EST 1993

DOI:https://doi.org/10.2172/10142663· OSTI ID:10142663

McCoy, B J; Smith, J M; Wang, M; Zhang, C J

The overall objective of this project was to study the supercritical fluid extraction of hydrocarbons from coal. Beyond the practical concern of deriving products from coal, the research has provided insights into the structure, properties, and reactivities of coal. Information on engineering fundamentals of coal thermolysis and extraction, including physical and chemical processes, is presented in this final report. To accomplish the goals of the project we developed continuous-flow experiments for fixed-bed samples of coal that allow two types of analysis of the extract: continuous spectrophotometric absorbance measurements of the lumped concentration of extract, and chromatographic determinations of molecular-weight distributions as a function of time. Thermolysis of coal yields a complex mixture of many extract products whose molecular-weight distribution (MWD) varies with time for continuous-flow, semibatch experiments. The flow reactor with a differential, fixed bed of coal particles contacted by supercritical t-butanol was employed to provide dynamic MWD data by means of HPLC gel permeation chromatography of the extract. The experimental results, time-dependent MWDs of extract molecules, were interpreted by a novel mathematical model based on continuous-mixture kinetics for thermal cleavage of chemical bonds in the coal network. The parameters for the MWDs of extractable groups in the coal and the rate constants for one- and two-fragment reaction are determined from the experimental data. The significant effect of temperature on the kinetics of the extraction was explained in terms of one- and two-fragment reactions in the coal.

• Research Organization: California Univ., Davis, CA (United States). Dept. of Chemical Engineering
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: FG22-90PC90288
• OSTI ID: 10142663
• Report Number(s): DOE/PC/90288--T9; ON: DE93012466
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010405
010600
010900
CHEMICAL BONDS
CLEAVAGE
COAL
DISTRIBUTION
ENVIRONMENTAL ASPECTS
HYDROGENATION AND LIQUEFACTION
KINETICS
LIQUID COLUMN CHROMATOGRAPHY
MOLECULAR WEIGHT
PROGRESS REPORT
PROPERTIES AND COMPOSITION
PYROLYSIS
SUPERCRITICAL GAS EXTRACTION
TEMPERATURE DEPENDENCE