Catalytic conversion of olefins to higher hydrocarbons

DETAILED DESCRIPTION What is claimed is: 1.
A continuous process for converting lower olefins to higher hydrocarbons with optional operation to maximize either distillate or gasoline product comprising: (a) combining a pressurized liquid olefinic feedstock containing a substantial fraction of lower olefins with a pressurized liquid low alkane stream comprising a major fraction of C.
sub.
3 -C.
sub.
4 alkanes; (b) pre-heating the combined olefinic stream and lower alkane stream to a temperature of at least about 230.
degree.
C.
; (c) contacting the pre-heated combined olefinic stream with an acid ZSM-5 type catalyst in a pressure reactor zone to convert a major portion of the lower olefin fraction to C.
sub.
5.
sup.
+ hydrocarbons in the gasoline boiling and distillate range; (d) cooling the reactor effluent from step (c); (e) debutanizing the cooled reactor effluent directly at less than reactor pressure to recover condensed lower alkane stream and a liquid C.
sub.
5.
sup.
+ hydrocarbon stream, including heat exchanging the reactor effluent indirectly with the liquid C.
sub.
5.
sup.
+ hydrocarbon stream in a debutanizer reboiler section; (f) recycling and pumping to reactor pressure at least a portion of the condensed lower alkane stream to step (a); and (g) fractionating the C.
sub.
5.
sup.
+ hydrocarbon stream to obtain a distillate product fraction and a gasoline-boiling range fraction.
2.
The process of claim 1 wherein the olefinic feedstock consists essentially of C.
sub.
2 -C.
sub.
5 aliphatic hydrocarbons containing a major fraction of monoalkenes in the essential absence of dienes or other deleterious materials.
3.
The process of claim 2 wherein the olefinic feedstock contains about 50 to 75 mole % C.
sub.
3 -C.
sub.
5 alkenes; wherein said pre-heated combined stream is contacted with the catalyst at a weight hourly space velocity of about 0.
5 to 2; wherein said recycled lower alkane contains at least 80 mole % C.
sub.
3 -C.
sub.
4 alkanes and is combined with olefinic feedstream at a mole ratio of about 0.
5:1 to 2:1, based on olefin in fresh feed; and wherein said catalyst comprises HZSM-5