GB479488A - A process for the refining of lignite tar, shale tar, peat tar and the like - Google Patents

Abstract

In a process for working up crude tars, such as lignite, shale or peat tars, the tar is topped to about 260 DEG C., and the residue treated at above 50 DEG C. with a selective solvent preferably low boiling phenols, whereby non-paraffinic components, asphalts and resins are removed. The phenols may be used alone or diluted with water, esters, ketones, or lower alcohols which decrease the solvent power of the phenol. If the topped tar is dewaxed or diluted with benzine or similar solvent a lower extraction temperature, e.g. 30 DEG C. is used. In an example, the crude tar is topped to about 200--220 DEG C and then to 260 DEG C. The first fraction is freed from the phenols and cresols which it contains, and these are used as the selective solvent subsequently. The residue of this fraction is used as a motor fuel, and the second fraction (220--260 DEG C.) after refining, e.g. with sulphur dioxide, is used as a Diesel fuel. The topped tar is then extracted at 50--60 DEG C. with the phenols obtained from the first fraction mixed with about 10 per cent of water. The mixture is separated in a centrifuge and the raffinate is freed from the phenol by distillation in vacuo. This oil is then de-waxed by chilling and separating the wax. The wax may be further purified by sweating and treating with sweated wax with ash-free coke. The de-waxed oil may be further extracted with selective solvent to form lubricating oils, or submitted to cracking or hydrogenation to form motor and Diesel fuels. The extracts obtained are preferably detected with benzine and the precipitated material is separated. Phenols and benzine are recovered from each fraction. This raffinate may be used as Diesel fuel, and the asphaltic extract after removal of wax, if any, is worked up into a road-surfacing material, for example by oxidation or by distilling off the light oils.