Extraction of coal using supercritical water

Reactions at supercritical conditions: Applications and fundamentals

“…Using an SCF provides several advantages. Coal thermolysis in an SCF (rather than in an inert gas) provides improved solubility for the primary products, and can prevent cracking reactions to gases (Adschiri et al, 1991a) and/or condensation reactions to form char (Deshpande et al, 1984). An additional mechanism of action of an SCF is to penetrate the microporous structure of the coal and extract or react with material physically trapped within the micropores (Kershaw, 1989).…”

“…displays the ability of one of these dynamic models to capture the key features of the extraction process during a temperature-programmed experiment. Deshpande et al (1984) investigated the reactive extraction of hydrocarbons from coal using SC water in a batch autoclave, which permitted rapid injection of the coal sample into the SCF medium. They found that the amount of material extracted increased with the SCF density.…”

Supercritical extraction of used automotive tire with water.

“…Deshpande et al 8) studied liquefaction of coal, lignite and glucose with supercritical water. Towneet al 18) also studied coal liquefaction in supercritical aqueous mixtures containing tetrahydroquinoline, quinoline or tetralin.…”

Extraction by Subcritical and Supercritical Water, Methanol, Ethanol and Their Mixtures

“…Supercritical water was found to act as both an extracting solvent as well as a reactant, converting coal to liquid and gaseous products [32]. Supercritical water at 633-673 K applied to sub-bituminous coals resulted in 36% to 44% total conversion [25].…”