Coal Industry (patents) Limited

Terry D Rantell

Geoffrey M Kimber

James W Clarke

Gordon Dennison

Diana Louise Tosswill

Michael Anthony Jorro

Colin E Snape

Recycled oil solvents for coal extraction have their content of saturated cyclic species reduced by thermal cracking at 470.degree. to 540.degree. C. for a few minutes, restoring their effectiveness as solvents for coal.

Coal extraction

Coal is extracted using a mixed solvent which includes a substantially aromatic component and a substantially naphthenic component, at a temperature of 400.degree. to 500.degree. C. Although neither component is an especially good solvent for coal by itself, the use of mixed solvent gives greater flexibility to the process and offers efficiency gains.

Coal extracts from hydrogenative liquid extraction of coals can be more easily and more quickly filtered if the extraction is carried out at a temperature over 420.degree. C. and the resulting extract is fractionated using a cut point in the range 200.degree. to 300.degree. C. to remove low boiling material. The product is then filtered to give a filtrate containing less than 0.1% by weight of mineral matter.

Carbon composites are made by mixing carbonizable binder, calcined coke grist and carbon fibre rods or needles of carbon fibre bundles in a hardened matrix, shaping the mixture into an artefact and carbonizing the binder, optionally with graphitizing. The composites may be used as carbon electrodes and have a low coefficient of thermal expanson.

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Cheltenham, United Kingdom

Terry D Rantell