REMOVAL OF POLYMER FROM CRACKED GAS CAUSTIC WASHES OR CAUSTIC SOLUTIONS

A cracked hydrocarbon gas, e.g., an effluent resulting from the pyrolytic conversion of a feed consisting essentially of ethane to form ethylene, is treated conventionally to produce a stream containing essentially ethylene which is treated with an alkali wash. The used alkali containing solid and other polymer formed therein and polymer-forming constituents is periodically or continuously treated by contacting the same with a solvent, e.g., an aromatic, to remove said polymers and polymer forming constituents. The used solvent is treated by contact with an adsorbent, e.g., activated charcoal or carbon or functional equivalent, to remove from the solvent polymer and polymer-forming constituents, rendering the solvent suitable for reuse and avoiding ultimate plugging of pumps, pipes, heat exchangers and other equipment. Polymers removed from the alkali wash can be liquid but usually are substantially solid and are at least to a real extent insoluble in the alkali wash. Polymer-forming constituents usually will not be entirely dissolved in the alkali wash. By use of the adsorbent to remove polymer-formers, and polymers, the formation of polymers in the alkali wash is considerably reduced if not completely avoided.