Process for the production of jet-range hydrocarbons

Abstract

A method for producing jet-range hydrocarbons includes passing a renewable olefin feedstock comprising C 3 to C 8 olefins to an oligomerization reactor containing a zeolite catalyst to produce an oligomerized effluent, separating the oligomerized effluent into at least a light stream, and a heavy olefin stream. At least a first portion of the heavy olefin stream is recycled to the oligomerization reactor to dilute the renewable olefin feedstock. portion of heavy olefin stream may be hydrogenated and separated to provide a jet range hydrocarbon product.

1 . process for producing hydrocarbons comprising:
 oligomerizing a renewable olefin feedstock comprising C 3  to C 8  olefins in an oligomerization reactor containing a catalyst comprising a MTT zeolite that has not been selectivated and operating the oligomerization reactor under conditions to produce an oligomerized effluent;   separating the oligomerized effluent to produce a light hydrocarbon stream, a naphtha hydrocarbon stream and a heavy stream comprising C 8 + olefins;   splitting the heavy stream into a first portion and a second portion; and,   diluting the renewable olefin feedstock with the first portion of the heavy stream.   
     
     
         2 . The process of  claim 1  further comprising:
 controlling a flow rate of the first portion of the heavy stream. 
 
     
     
         3 . The process of  claim 2  wherein the flow rate of the first portion of the heavy stream is controlled to obtain a ΔT from an inlet to an outlet in the oligomerization reactor of at least 25° C. and no more than 60° C. 
     
     
         4 . The process of  claim 1  further comprising:
 hydrogenating the second portion of the heavy stream in a hydrogenation zone having a hydrogenation reactor to provide a hydrogenated stream. 
 
     
     
         5 . The process of  claim 4  further comprising:
 separating the hydrogenated stream into a vent gas stream and a saturated distillate stream. 
 
     
     
         6 . The process of  claim 5  further comprising:
 separating the saturated distillate stream into a saturated jet range stream and a saturated diesel range hydrocarbons stream. 
 
     
     
         7 . The process of  claim 5  further comprising:
 recycling at least a portion of the saturated distillate stream to the hydrogenation zone. 
 
     
     
         8 . process for producing hydrocarbons comprising:
 passing a renewable olefin feedstock comprising C 3  to C 8  olefins to an oligomerization reaction zone comprising an oligomerization reactor containing a catalyst comprising a non-selectivated MTT zeolite and wherein said oligomerization reactor is operating under conditions to produce an oligomerized effluent;   passing the oligomerized effluent to a first separation zone to provide at least one stream comprising C 7−  hydrocarbons and a C 8+  olefin stream;   splitting the C 8+  olefin stream into a first portion and a second portion; and,   recycling the first portion of the C 8+  olefin stream to the oligomerization reaction zone.   
     
     
         9 . The process of  claim 8  further comprising:
 combining the first portion of the C 8+  olefin stream with the renewable olefin feedstock to provide a combined stream; and, 
 passing the combined stream into the oligomerization reactor. 
 
     
     
         10 . The process of  claim 8  wherein the first separation zone produces a light hydrocarbon stream and a naphtha hydrocarbon stream. 
     
     
         11 . The process of  claim 8  further comprising:
 passing the second portion of the C 8+  olefin stream to a hydrogenation zone having a hydrogenation reactor containing a catalyst and being operated to provide a hydrogenated effluent. 
 
     
     
         12 . The process of  claim 11  further comprising:
 passing the hydrogenated effluent to second separation zone to provide at least a vent gas stream and a saturated jet range stream. 
 
     
     
         13 . The process of  claim 12  further comprising:
 recycling a portion of the hydrogenated effluent to the hydrogenation zone as a recycle stream. 
 
     
     
         14 . The process of  claim 13  further comprising:
 combining the recycle stream and the second portion of the C 8+  olefin stream into a combined stream; and, 
 passing the combined stream to the hydrogenation reactor. 
 
     
     
         15 . The process of  claim 11  further comprising:
 passing the hydrogenated effluent to a second separation zone having at least two columns. 
 
     
     
         16 . The process of  claim 15  wherein a first column in the second separation zone separates the hydrogenated effluent into a vent gas stream and a saturated distillate stream. 
     
     
         17 . The process of  claim 16  wherein a second column in the second separation zone separates the saturated distillate stream into a saturated jet range stream and a saturated diesel stream. 
     
     
         18 . The process of  claim 17  further comprising:
 passing at least a portion of the saturated distillate stream to the hydrogenation reaction zone as a recycle stream. 
 
     
     
         19 . The process of  claim 8  further comprising:
 controlling a temperature rise in the oligomerization reactor by adjusting a flow rate of the first portion of the C 8+  olefin stream. 
 
     
     
         20 . The process of  claim 8  further comprising:
 increasing a flow rate of the first portion of the C 8+  olefin stream to decrease a temperature rise in the oligomerization reactor.