US 4,456,779 A · Catalytic conversion of olefins to higher hydrocarbons

Abstract

An improved continuous process for converting lower olefinic hydrocarbon feedstock to C.sub.5.sup.+ liquid hydrocarbons by contacting vapor phase olefinic feedstream with acid zeolite catalyst in the presence of recycled diluent stream rich in C.sub.3 -C.sub.4 hydrocarbons in an enclosed reactor at elevated temperature and pressure. The improved technique comprises a system for cooling reactor effluent to recover a heavier hydrocarbon stream containing a mixture of C.sub.3 -C.sub.4 hydrocarbons and C.sub.5.sup.+ hydrocarbons and debutanizing the heavier hydrocarbons below reactor pressure to obtain a C.sub.5.sup.+ product stream and a condensed C.sub.3 -C.sub.4 hydrocarbon stream. Operating efficiencies are realized in the heat exchange system by reboiling the debutanized C.sub.5.sup.+ hydrocarbon product stream with hot reactor effluent, and by recycling and combining at least a portion of the condensed C.sub.3 -C.sub.4 hydrocarbon stream to dilute liquid olefin hydrocarbon feedstock. By increasing pressure on the liquid olefinic hydrocarbon feedstock and liquid recycle stream to at least the elevated reactor pressure in the liquid state prior to vaporization, energy is conserved.

Claims12

Dependent claims

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.

5 more elements

In the continuous process for converting lower olefinic hydrocarbons to C.sub.5.sup.+ liquid hydrocarbons by contacting olefinic feedstock with acid zeolite catalyst in the presence of a recycled diluent stream rich in C.sub.3 -C.sub.4 hydrocarbons in an enclosed reactor at elevated temperature and pressure, the improvement which comprises:

cooling reactor effluent to recover a heavier hydrocarbon stream containing a mixture of C.sub.3 -C.sub.4 hydrocarbons and C.sub.5.sup.+ hydrocarbons,
debutanizing said heavier hydrocarbon stream reactor effluent in a debutanizer tower operated below reactor pressure to obtain a C.sub.5.sup.+ liquid product stream and a condensed C.sub.3 -C.sub.4 hydrocarbon stream;
exchanging heat between the C.sub.5.sup.+ liquid debutanizer stream and hot reactor effluent;
recycling and combining at least a portion of the condensed C.sub.3 -C.sub.4 hydrocarbon stream to dilute liquid olefin hydrocarbon feedstock;
and
increasing pressure on the liquid olefinic hydrocarbon feedstock and liquid recycle stream to at least the elevated reactor pressure in the liquid state prior to vaporization.

3 more elements

Dependencies are inferred from the claim text.

Catalytic conversion of olefins to higher hydrocarbons

Life of this patent

Catalytic conversion of olefins to higher hydrocarbons

Life of this patent

Abstract

Claims12