PROCESS FOR REDUCING VAPOR CONDENSATION IN FLASH/SEPARATION APPARATUS OVERHEAD DURING STEAM CACKING OF HYDROCARBON FEEDSTOCKS

摘要

A process for reducing fouling during cracking of a hydrocarbon feedstock containing resid is provided which comprises: introducing a mixture stream of heated hydrocarbon feedstock mixed with steam to a flash/separation apparatus to form (i) a vapor phase at its dew point which partially cracks causing a temperature decrease and partial condensation of said vapor phase in the absence of added heat and (ii) a liquid phase. Partial condensation is reduced by adding a heated vaporous diluent, e.g., light hyrocarbon or superheated steam, to the flash/separation apparatus to an extent sufficient to at least partially compensate for the temperature decrease and to dilute and superheat the vapor phase, prior to removing the vapor phase as overhead for subsequent cracking and recovery of cracked product. An apparatus for carrying out the process is also provided.