METHOD OF TREATING AND UTILIZING HEAVY PYROLYSIS TAR Russian patent published in 2004 - IPC

FIELD: petroleum processing and petrochemistry. SUBSTANCE: in the first stage, tar-water system with more than 40% water is watered to raise water content to 60-70%, after which treated with 100-300 mg/l of coagulant to separate phases while simultaneously lowering water in tar to 5-10%. Thus dewatered tar and initial tar with less than 40% water are subjected to thermochemical treatment, initial tar being preliminarily mixed with light pyrolysis oil at ratio to water contained in initial tar (0.5-1):1 to form oil/water heteroazeotrope with boiling temperature 70-90 C. Tars are then subjected to heat treatment to 120 C accompanied with continuous purging tar with nitrogen or flue gases in presence of surfactants reducing foaming, which results in stripping of light hydrocarbons with water vapors. Residual product is heavy pyrolysis tar with flash temperature no less than 85 C and water level no higher than 1.5%. Heavy tar can be used as synthetic fuel, wood impregnation material whereas, separated from water, light pyrolysis oil with flash temperature no higher than 120 C and 56-60% aromatic hydrocarbons can be used as organic solvent. EFFECT: increased degree of dewatering and shortened process time. 5 tbl, 4 ex