Patent ID: 7495141

Claim:
A process for reducing corrosion in an MTO reactor system, the process comprising the steps of: (a) contacting a product stream from an MTO reactor with a quench medium in a quench unit under conditions effective to form a first overhead stream and a first bottoms stream, wherein the first overhead stream comprises light olefins, and wherein the first bottoms stream comprises the quench medium and condensed oxygenates; (b) directing at least a portion of the first bottoms stream to a condensate stripper; (c) heating the at least a portion of the first bottoms stream in the condensate stripper under conditions effective to form a second overhead stream and a second bottoms stream, wherein the second overhead stream contains recovered oxygenates, and wherein the second bottoms stream contains stripped quench medium; (d) partially vaporizing at least a portion of the second bottoms stream to form a vaporized phase and a liquid phase, wherein the liquid phase has a pH; (e) adding a neutralization agent to the liquid phase to form a treated stream having a pH greater than the pH of the liquid phase; (f) compressing the light olefins in the first overhead stream to form a compressed product fraction: (g) directing the compressed product fraction to a C 3− separation zone and forming a C 3− overhead stream and a C 4+ bottoms stream; and (h) contacting at least a portion of the C 3− overhead stream with caustic in a caustic wash unit and forming a caustic unit overhead stream and a caustic unit bottoms stream, wherein the caustic unit overhead stream contains a majority of the light olefins that were present in the light product fraction, and wherein the caustic unit bottoms stream contains at least partially spent caustic.