Recovery of ethylene from methanol to olefins process

摘要

Olefins may be recovered from a methanol to olefins reactor effluent by initially feeding the effluent to an absorber demethanizer to contact the effluent with an absorbent to recover an overheads including methane and ethylene and a bottoms including the absorbent, ethylene, and ethane. The bottoms are separated to recover an ethylene fraction and an ethane fraction. The overheads are cooled and partially condensed in a first heat exchanger to a temperature of −40° C. or greater. The resulting stream, or a portion thereof, may be further cooled and condensed via indirect heat exchange with a mixed refrigerant to a temperature of less than −40° C. The non-condensed vapors are separated from the condensed liquids to form a liquid fraction and a methane fraction. The liquid fraction is fed to the absorber demethanizer as reflux, and the methane and ethane fractions combined to form the mixed refrigerant.

主权项

1. A process for recovery of the olefins from a methanol to olefins reactor effluent, the process comprising:
feeding an effluent from a methanol-to-olefins reactor system comprising methane, ethylene, and ethane to an absorber demethanizer; contacting at least a portion of the effluent with an absorbent in the absorber demethanizer to recover an overheads vapor fraction comprising methane and ethylene and a bottoms fraction comprising the absorbent, ethylene, and ethane; separating the bottoms fraction via one or more extractive distillation and/or distillation stages to recover an ethylene fraction and an ethane fraction; cooling and partially condensing the overheads vapor fraction in a first heat exchanger to a temperature of about −40° C. or greater; cooling and partially condensing at least a portion of the cooled and partially condensed overhead vapor fraction, via indirect heat exchange with a mixed refrigerant in a second heat exchanger, to a temperature of less than about −40° C.; separating non-condensed vapors from the liquids condensed in the first and second heat exchangers to form an overhead liquid fraction and a methane fraction; feeding the overhead liquid fraction to the absorber demethanizer as a reflux; combining at least a portion of the methane and ethane fractions to form the mixed refrigerant.