Process for preheating cracked gas before caustic tower treatment in ethylene plants

摘要

An inline, high-shear mixer (20) is provided in a cracked gas stream (12) upstream of a caustic tower (38) in an ethylene production unit. Spent caustic (52) is withdrawn from the bottom of the caustic tower (38) and pumped to the mixer (20), where the spent caustic mixes with and absorbs acid gas components from the cracked gas stream (12). The spent caustic is separated from the cracked gas, forming a partially treated cracked gas stream (26). The partially treated cracked gas stream (26) is then fed to the caustic tower (38). Polymer deposition in the caustic tower (38) is reduced because polymeric material is formed when the cracked gas stream is mixed with the spent caustic and is removed before the cracked gas stream is fed to the caustic tower (38).