Hydrothermal pretreatment of coal

Technical Report · Tue Jul 02 00:00:00 EDT 1991

OSTI ID:5509329

Loo, B; Ross, D S

We have studied the effects of hydrothermal treatment liquid water at elevated temperatures on Wyodak coal. The runs were carried out for 30 min and 5 hr, and we found that little change took place in the coal at 150{degrees} and 250{degrees}C. However, at 350{degrees}C the coal was changed substantially. Water promoted hydrolysis of the ether linkages in the coal matrix, releasing phenolic and other components. In control runs in which the water was replaced by undecane (n-C{sub 11}H{sub 24}), the phenolic components were not released, and in the extended (5-hr) treatment the product coal was essentially a char. Water also promoted the evolution of a tar, which was not seen in the undecane control run or in controls in which the coal was simply heated under nitrogen. Water did not affect the thermal loss of oxygen in the 30-min runs, which demonstrates that initial thermal oxygen loss yielding water is irreversible. However, the water-treatment in the 5-hr runs brought about additional O loss, presumably because of extensive hydrolytic elimination of phenolics and dihydroxybenzenes. The results are consistent with a scheme in which water assists in the removal of potential condensation promoters such as the dihydroxybenzenes but the alkane medium, on the other hand, acts as an antisolvent, suppressing the diffusion of thermally generated fragments, which become irreversibly reincorporated in the matrix. 30 refs., 2 tabs.

• Research Organization: SRI International, Menlo Park, CA (United States)
• Sponsoring Organization: USDOE; USDOE, Washington, DC (United States)
• DOE Contract Number: AC22-89PC89880
• OSTI ID: 5509329
• Report Number(s): DOE/PC/89880-T2; ON: DE91018056
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
ALKANES
CHEMICAL REACTIONS
SUBBITUMINOUS COAL
HYDROLYSIS
WATER
CHARS
COPROCESSING
OXYGEN
PHENOLS
PROGRESS REPORT
TAR
AROMATICS
CARBONACEOUS MATERIALS
COAL
DECOMPOSITION
DOCUMENT TYPES
ELEMENTS
ENERGY SOURCES
FOSSIL FUELS
FUELS
HYDROCARBONS
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
LYSIS
MATERIALS
NONMETALS
ORGANIC COMPOUNDS
OTHER ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PROCESSING
PYROLYSIS PRODUCTS
SOLVOLYSIS
010402* - Coal
Lignite
& Peat- Purification & Upgrading
010600 - Coal
Lignite
& Peat- Properties & Composition