ROLE OF SOLVENT DEASPHALTING IN PROCESSING PETROLEUM RESIDUES IN REFINERIES

Abstract

Solvent Oeasphalting (SOA) is basically a liquid-liquid extraction process. The conventional applications are in producing extra heavy viscosity grade lube oils called bright stock/cylinder oils and in upgrading bottom of barrel by recovering incremental/ additional feedstocks from vacuum residues for secondary conversion units like Fluid CatalyticCracking/Hydrocracking. Some newer applicationsinclude making of quality bitumen from waxy crudes, low sulpher fuel oils etc. Industrially,propane, butane and pentane (C3-CJ solvents, either alone or there combinationsfor greater flexibility,are being used widely. To improve the process economics, novel features like supercritical solvent recovery, better counter current columns, etc. are being incorporatedin existing and new grass-root deasphalting plants. The SOA process in combination with thermal cracking processes etc. is further contributing in reducing the availabilityof short/vacuum residues in refinerie