The chemical nature of supercritical gas extracts from low-rank U. K. coals

Abstract

Two processes are being developed by the National Coal Board for producing liquids from coal. Both involve extraction of the coal to produce an extract, freed from mineral matter, which is then catalytically hydrocracked. This approach is particularly suitable for producing transport fuels and chemical feedstocks. One process uses as solvent a process-derived liquid. The other uses a compressed supercritical gas to extract the more hydrogen-rich parts of the coal, leaving a reactive char which can provide the necessary hydrogen, heat and power for the process. As part of the development programme, extracts have been prepared by gas extraction over a range of conditions, and their chemical structures investigated by elemental and spectroscopic analysis. The average structures so derived consist of small aromatic clusters joined by methylene, ether and diphenyl linkages. Extracts produced by the liquid solvent route contain larger aromatic clusters.

Reactions at supercritical conditions: Applications and fundamentals

“…They reported a 19% yield at 360°C and 11.6 MPa, and the yield increased to 32% at 29 MPa. The chemical nature of the compounds extracted into SC toluene have also been examined (Bartle et al, 1975(Bartle et al, , 1979Tugrul and Okay, 1978;Martin and Williams, 1981).…”

Cross industry integration for power plants that utilize hydrocarbon fuels and supercritical fluids

“…The cumbersome solid-liquid separation train inherent in conventional direct liquefaction was eliminated while solvent recovery and environmental issues were minimized. Typical coal products [19] from SGE characterized methods discussed by Herod [20] are shown in Fig. 7, while effect of temperature on product characteristics as a function of solvent strength is shown in Fig.…”