CONTROL TECHNIQUE FOR CONVERSION OF OXYGENATES TO LIQUID HYDROCARBONS

摘要

A process control technique for upgrading C3-C4 hydrocarbon feed containing olefins to produce heavier liquid hydrocarbons comprising converting a major portion of C3-C4 olefins in an oligomerization zone by contacting a shape selective medium pore zeolite catalyst at elevated temperature and pressure to make distillate and olefinic gasoline. The oligomerization stage effluent is fractionated to provide distillate and gasoline product and a C3-C4 intermediate stream containing isobutane and unconverted propene and butylene. The C3-C4 intermediate stream is combined under control with a portion of C3-C4 feed and further converting the combined streams in an alkylation zone to make heavier paraffinic hydrocarbons. The olefin feed may be produced by catalytically converting methanol or similar oxygenated hydrocarbons in a known process. Controlled material balance is achieved by accumulating liquid olefin feed to the oligomerization and alkylation units using a surge drum with liquid level control. By-product isobutane is recovered and recycled under liquid level control operatively connected to determine feed of liquid olefin to the conversion units.