METHOD OF COOLING AND TREATING PYROLYSIS PRODUCTS BEFORE COMPRESSION AND GAS SEPARATION Russian patent published in 2003 - IPC

FIELD: petrochemical processes. SUBSTANCE: invention relates to production of ethylene via pyrolysis of hydrocarbon feedstock, in particular to stages indicated in the title. Method of invention comprises consecutive cooling in quenching-evaporative apparatuses, on primary fractionation column, and on water washing column, routing still product from primary fractionation column to cool pyrolysis gas in direct contact mode and to be used as reflux in medium section of primary fractionation column, whereas hydrocarbon layer of still product from water washing column is used as reflux in upper section of primary fractionation column. Temperature at primary fractionation column outlet does not exceed 110 C. When liquefied hydrocarbons or their mixture with liquid hydrocarbon feedstock (less than 50 wt %) or mixture of liquefied hydrocarbons with ethane fraction (less than 60 wt %) is used as pyrolysis hydrocarbon feedstock, hydrocarbon fraction 160-380 C is added to still product of primary fractionation column, which is fed for cooling pyrolysis products by direct contact mode and into medium section of primary fractionation column as reflux, whereas hydrocarbon fraction 35-190 C from compression and gas separation unit is used as reflux in upper section of primary fractionation column. Liquefied hydrocarbons utilized is propane-butane fraction or long fraction of light-weight C3-C6-hydrocarbons, or polyalkylbenzenes, and liquid hydrocarbon feedstock is gasoline fraction. Hydrocarbon fraction 160- 380 C, which is added in amounts 2,5 to 6% of the weight of pyrolysis gas being cooled, is corresponding petroleum distillation fraction or polyalkylbenzenes. Hydrocarbon fraction 35-190 C is added in such amount as to maintain temperature of primary fractionation column top within a range of 102-110 C. EFFECT: enabled balanced process to yield pyrolysis condensate boiling no higher than 90 C. 4 cl, 1 dwg, 1 tbl