Process for converting olefins to jet fuel with dealkanizer

Abstract

A process for oligomerizing olefins to distillate fuels which oligomerizes a recycle olefin stream with charge olefin streams in a first-stage oligomerization reactor. The first-stage oligomerate is oligomerized in a second-stage oligomerization reactor to provide a second-stage oligomerate stream. A recycle olefin stream is taken from said second-stage oligomerate stream. A dealkanizer column can be used to remove light alkanes that would be inert and accumulate in a recycle loop. The second-stage oligomer product stream is hydrogenated to produce fuels.

1 . A process for oligomerizing an olefin stream comprising:
 oligomerizing a charge olefin stream over a first-stage oligomerization catalyst to produce a first-stage oligomerized stream;   oligomerizing said first-stage oligomerized stream over a second-stage oligomerization catalyst to provide a second-stage oligomerized stream; and   dealkanizing said second-stage oligomerized stream to provide a light alkane stream and a dealkanized stream.   
     
     
         2 . The process of  claim 1  further comprising oligomerizing said charge olefin streams with a recycle olefin stream over said first-stage oligomerization catalyst and taking said recycle olefin stream from said dealkanized stream. 
     
     
         3 . The process of  claim 2  wherein taking said recycle olefin stream from said dealkanized stream further comprises splitting said dealkanized stream into a light olefin stream and a heavy olefin stream and taking said recycle olefin stream from said light olefin stream. 
     
     
         4 . The process of  claim 3  wherein taking said recycle olefin stream from said light olefin stream further comprises separating said light olefin stream to provide a light off-gas stream and a light liquid overhead stream and taking said recycle olefin stream from said light liquid overhead stream. 
     
     
         5 . The process of  claim 1  further comprising splitting said dealkanized stream into a light olefin stream and a heavy olefin stream. 
     
     
         6 . The process of  claim 5  further comprising recycling a recycle olefin stream taken from said light olefin stream to said oligomerizing step over said first-stage oligomerization catalyst. 
     
     
         7 . The process of  claim 6  further comprising separating said light olefin stream to provide a light olefin condensate stream and taking a portion of said light olefin condensate stream as said recycle olefin stream. 
     
     
         8 . The process of  claim 7  wherein taking said recycle olefin stream further comprises separating said light olefin stream to provide a light off-gas stream and a light liquid overhead stream and taking said recycle olefin stream from said light liquid overhead stream. 
     
     
         9 . The process of  claim 1  wherein said recycle olefin stream comprises C4 to C8 olefins. 
     
     
         10 . The process of  claim 3  wherein said recycle olefin stream is obtained by separating said light alkane stream to provide an off-gas stream and a light alkane condensate stream and taking said recycle olefin stream from said light alkane condensate stream. 
     
     
         11 . The process of  claim 1  further comprising combusting said off-gas stream to provide heating requirements in said process. 
     
     
         12 . A process for oligomerizing an olefin stream comprising:
 oligomerizing a charge olefin stream and a recycle olefin stream over a first-stage oligomerization catalyst to produce a first-stage oligomerized stream;   oligomerizing said first-stage oligomerized stream over a second-stage oligomerization catalyst to provide a second-stage oligomerized stream;   dealkanizing said second-stage oligomerized stream to provide a light alkane stream and a dealkanized stream; and   taking said recycle olefin stream from said dealkanized stream.   
     
     
         13 . The process of  claim 12  wherein taking said recycle olefin stream from said dealkanized stream further comprises splitting said dealkanized stream into a light olefin stream and a heavy olefin stream and taking said recycle olefin stream from said light olefin stream. 
     
     
         14 . The process of  claim 13  wherein taking said recycle olefin stream from said light olefin stream further comprises separating said light olefin stream to provide a light off-gas stream and a light liquid overhead stream and taking said recycle olefin stream from said light liquid overhead stream. 
     
     
         15 . The process of  claim 14  further comprising splitting said dealkanized stream into a light olefin stream and a heavy olefin stream. 
     
     
         16 . The process of  claim 15  further comprising recycling a recycle olefin stream taken from said light olefin stream to said oligomerizing step over said first-stage oligomerization catalyst. 
     
     
         17 . The process of  claim 16  further comprising separating said light olefin stream to provide a light olefin condensate stream and taking a portion of said light olefin condensate stream as said recycle olefin stream. 
     
     
         18 . The process of  claim 17  wherein taking said recycle olefin stream further comprises separating said light olefin stream to provide a light off-gas stream and a light liquid overhead stream and taking said recycle olefin stream from said light liquid overhead stream. 
     
     
         19 . A process for oligomerizing an olefin stream comprising:
 oligomerizing a charge olefin stream and a recycle olefin stream over a first-stage oligomerization catalyst to produce a first-stage oligomerized stream;   oligomerizing said first-stage oligomerized stream over a second-stage oligomerization catalyst to provide a second-stage oligomerized stream;   dealkanizing said second-stage oligomerized stream to provide a light alkane stream and a dealkanized stream;   separating said light alkane stream to provide an off-gas stream and a light alkane condensate stream and taking said recycle olefin stream from said light alkane condensate stream.   
     
     
         20 . The process of  claim 1  further comprising combusting said off-gas stream to provide heating requirements in said process.