A study of depolymerization and crosslinking reactions in coal liquefaction: Eleventh quarterly report for the period March 1, 1988--May 31, 1988

Technical Report · Fri Jan 01 04:00:00 EST 1988

OSTI ID:6887949

Solomon, P R; Deshpande, G V; Serio, M A; Kroo, E

The major goal of this program is to characterize the depolymerization and crosslinking reactions of low rank coals and determine how they can be optimized in liquefaction by combining high heating rates with solvent interactions. High heating rates are achieved by using a heated tube reactor where coal is heated at about 20,000 /degree/C/sec. Solvent interactions to stabilize depolymerization fragments formed at high heating rates are achieved by: co-injection of a donor solvent into the heated tube reactor, preswellling the coal at elevated temperatures (100/degree/C) and pyrolyzing the swelled coal in the heated grid or heated tube reactors and injecting rapidly preheated coal into a hot solvent. Crosslinking and depolymerization reactions are also being studied by using polymers to simulate the chemistry occurring in coal. In order to determine the rank dependence of liquefaction yields, experiments were carried out with North Dakota Zap lignite and Pittsburgh Seam bituminous coal at 400/degree/C and reaction times up to 30 minutes. The conversion to toluene solubles for the bituminous coal was found to be higher than the lignite. A strong dependence of temperature on the conversion to toluene solubles was observed for both the lignite and the bituminous coal. To assess the influence of the liquefaction solvent on the crosslinking of Zap lignite, chars were made in the presence of tetralin or helium at different temperatures. The coal was heated in an electrically heated tube reactor to the desired temperature and the temperature was held for 3 minutes. The crosslinking curve shifted to higher temperatures for the same loss in swelling for the chars formed in the presence of tetralin. Hence the presence of a hydrogen donor solvent like tetralin reduces the rate and extent of the crosslinking reactions. The mechanism may be capping some of the crosslinking sites with hydrogen donated by the tetralin. 4 refs.

• Research Organization: Advanced Fuel Research, Inc., East Hartford, CT (USA)
• DOE Contract Number: FG22-85PC80910
• OSTI ID: 6887949
• Report Number(s): DOE/PC/80910-T4; ON: DE88015497
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010405* -- Coal
Lignite
& Peat-- Hydrogenation & Liquefaction
BITUMINOUS COAL
BLACK COAL
BROWN COAL
CARBONACEOUS MATERIALS
CHARS
CHEMICAL REACTIONS
COAL
COAL LIQUEFACTION
CROSS-LINKING
DECOMPOSITION
DEPOLYMERIZATION
DOCUMENT TYPES
ENERGY SOURCES
FOSSIL FUELS
FUELS
HEATING RATE
HYDROGEN TRANSFER
LIGNITE
LIQUEFACTION
MATERIALS
ORGANIC SOLVENTS
POLYMERIZATION
PROGRESS REPORT
PYROLYSIS PRODUCTS
SOLVENTS
SWELLING
TEMPERATURE EFFECTS
THERMOCHEMICAL PROCESSES
YIELDS