Multi-stage system for converting oxygenates to liquid hydrocarbons with aliphatic recycle

Claim 2

A continuous multi-stage catalytic system for converting oxygenated feedstock to liquid hydrocarbons comprising primary stage fluidized bed catalytic reactor means containing acidic zeolite catalyst for converting oxygenate to olefinic hydrocarbons rich in C 2 -C 4 lower alkenes; means for charging feedstock at a bottom portion of said primary stage reactor means; secondary stage catalytic oligomerization reactor means containing medium pore shape selective acidic zeolite oligomerization catalyst for converting the lower alkenes from the primary stage to heavier liquid hydrocarbons; fractionation means for separating secondary stage effluent into a light hydrocarbon stream containing C 2 -C 4 aliphatic hydrocarbons, a C 5 .spsb.+ gasoline stream and distillate range stream; means for recovering and recycling at least a portion of the C 5 .spsb.+ gasoline stream to the primary stage for conversion in the fluidized bed reactor by injecting the recycled gasoline stream into the fluidized bed reactor at a midpoint thereof, thereby preventing substantial reaction with oxygenate.

Claim 3

The continuous system of claim 1 further comprising means for recovering as product at least a portion of the C 5 .spsb.+ gasoline stream from the primary and secondary stages.

Claim 4

A fluidized catalyst reactor system for converting oxygenated feedstock to liquid hydrocarbons comprising: primary stage reactor means for contacting feedstock vapor with a fluidized bed of catalyst at elevated temperature and moderate pressure to convert feedstock to hydrocarbons comprising C 2 -C 4 alkenes and C 5 .spsb.+ hydrocarbons; means for charging feedstock at a bottom portion of said primary stage reactor means; interstage phase separator means for cooling and separating primary stage effluent to recover a liquid hydrocarbon stream and a light hydrocarbon stream rich in C 2 -C 4 alkenes; compressor means for pressurizing the light hydrocarbon stream to condense a liquid olefinic hydrocarbon stream rich in C 3 .spsb.+ alkenes and recovering an ethene-rich gaseous stream; pump means for further pressurizing the condensed liquid olefinic hydrocarbon stream; secondary stage reactor means for contacting the condensed liquid olefinic stream with oligomerization catalyst comprising medium-pore shape selective acidic zeolite at high pressure and moderate temperature to convert at least a portion of the C 3 .spsb.+ alkenes to a heavier liquid hydrocarbon product stream comprising olefinic gasoline and distillate range liquids; means for recycling a portion of the olefinic gasoline to the primary stage reactor means; and means for injecting the olefinic gasoline recycle stream into the fluidized catalyst bed of the primary stage reactor at a point above the oxygenate feedstock charge means and above a bed stratum corresponding to substantially complete oxygenate conversion.

Claim 5

A fluidized catalyst reactor system for converting oxygenated feedstock to liquid hydrocarbons comprising: primary stage reactor means for contacting feedstock vapor with a fluidized bed of catalyst at elevated temperature and moderate pressure to convert feedstock to hydrocarbons comprising C 2 -C 4 alkenes and C 5 .spsb.+ hydrocarbons; means for charging feedstock at a bottom portion of said primary stage reactor means; interstage phase separator means for cooling and separating primary stage effluent to recover a liquid hydrocarbon stream and a light hydrocarbon stream rich in C 2 -C 4 alkenes; compressor means for pressurizing the light hydrocarbon stream to condense a liquid olefinic hydrocarbon stream rich in C 3 .spsb.+ alkenes and recovering an ethene-rich gaseous stream; pump means for further pressurizing the condensed liquid olefinic hydrocarbon stream; secondary stage reactor means for contacting the condensed liquid olefinic stream with oligomerization catalyst comprising medium-pore shape selective acidic zeolite at high pressure and moderate temperature to convert at least a portion of the C 3 .spsb.+ alkenes to a heavier liquid hydrocarbon product stream comprising olefinic gasoline and distillate range liquids; means for recycling a portion of the olefinic gasoline to the primary stage reactor means; and means for injecting the olefinic gasoline recycle stream into the fluidized catalyst bed of the primary stage reactor at a point above the oxygenate feedstock charge means and above a bed stratum corresponding to substantially complete oxygenate conversion.

Claim 6

The system of claim 3 comprising means for recovering at least a portion of the olefinic gasoline from the primary and secondary stage reactors.

Claim 7

The system of claim 3 wherein the recycle injection point is located above a bed stratum corresponding to at least 99% oxygenate conversion.

Claim 8

A continuous reactor system for converting oxygenate feedstock to predominantly distillate range liquid hydrocarbons comprising: primary fluidized bed catalytic reactor means for contacting the feedstock with conversion catalyst at elevated temperature and moderate pressure to convert feedstock to hydrocarbons comprising C 2 -C 4 olefins and C 5 .spsb.+ hydrocarbons; means for charging feedstock at a bottom portion of said primary stage reactor means; means for cooling and separating effluent from the primary stage to recover a liquid hydrocarbon stream and a light hydrocarbon vapor stream rich in C 2 -C 4 lower olefins; secondary catalytic reactor means for contacting the light olefinic hydrocarbon stream with oligomerization catalyst comprising medium-pore shape selective acidic zeolite at substantially increased pressure and moderate temperature to convert at least a portion of olefins to a heavier liquid hydrocarbon stream comprising olefinic gasoline and distillate range liquids; fractionation means for recovering a distillate product stream and an olefinic gasoline recycle stream from secondary stage effluent; and means for injecting at least a portion of the olefinic gasoline recycle stream into the fluidized catalyst bed of the primary stage reactor at a separate point above the oxygenate feedstock means and above a bed stratum corresponding to substantially complete oxygenate conversion.

Claim 9

A continuous reactor system for converting oxygenate feedstock to predominantly distillate range liquid hydrocarbons comprising: primary fluidized bed catalytic reactor means for contacting the feedstock with conversion catalyst at elevated temperature and moderate pressure to convert feedstock to hydrocarbons comprising C 2 -C 4 olefins and C 5 .spsb.+ hydrocarbons; means for charging feedstock at a bottom portion of said primary stage reactor means; means for cooling and separating effluent from the primary stage to recover a liquid hydrocarbon stream and a light hydrocarbon vapor stream rich in C 2 -C 4 lower olefins; secondary catalytic reactor means for contacting the light olefinic hydrocarbon stream with oligomerization catalyst comprising medium-pore shape selective acidic zeolite at substantially increased pressure and moderate temperature to convert at least a portion of olefins to a heavier liquid hydrocarbon stream comprising olefinic gasoline and distillate range liquids; fractionation means for recovering a distillate product stream and an olefinic gasoline recycle stream from secondary stage effluent; and means for injecting at least a portion of the olefinic gasoline recycle stream into the fluidized catalyst bed of the primary stage reactor at a separate point above the oxygenate feedstock means and above a bed stratum corresponding to substantially complete oxygenate conversion.

Claim 10

The system of claim 6 further comprising means for fractionating the vapor effluent separated from primary stage effluent to recover a recycle gas stream containing at least 90% of ethene from the primary catalytic stage and an olefinic stream rich in C 3 .spsb.+ olefins.

Claim 11

The system of claim 7 including means for recycling olefinic gasoline to the primary stage at a rate of about 1 to 30 parts gasoline per 100 parts by weight of hydrocarbon equivalent in the feedstock.