Process for converting unsaturated C4 hydrocarbons into normal butane

Claim 2

A process of converting unsaturated C 4 hydrocarbons into normal butane which comprises: a. passing a stream consisting essentially of unsaturated C 4 hydrocarbons in contact with hydrogen in a hydrogenation zone to react said hydrogen and said unsaturated C 4 hydrocarbons to form a stream of normal butane and isobutane; b. discharging said normal butane and isobutane stream from said hydrogenation zone and introducing said discharged normal butane and isobutane stream into a separation zone to separate said normal butane from said isobutane; c. discharging and recovering said normal butane from said separation zone; d. passing said isobutane from said separation zone into an isomerization zone to convert a portion of said isobutane into normal butane so that a stream of normal butane and isobutane is produced; and e. thereafter returning said stream of normal butane and isobutane produced in said isomerization zone into said separation zone to separate and recover the normal butane produced in said isomerization zone.

Claim 3

A process according to claim 1 wherein said normal butane recovered in step (c) is introduced into a cracking zone of an ethylene production facility as a feedstock for the production of ethylene.

Claim 4

A process according to claim 1 wherein said stream of unsaturated C 4 hydrocarbons is a butene raffinate stream generated in a butadiene recovery unit.

Claim 5

A process according to claim 1 wherein said stream of unsaturated C 4 hydrocarbons is a butene raffinate stream generated in a butadiene recovery zone of an ethylene production facility.

Claim 6

A process according to claim 1 wherein said hydrogen introduced into said hydrogenation zone is obtained from a demethanization zone of an ethylene production facility.

Claim 7

A process according to claim 1 wherein heat is generated in said hydrogenation zone and said heat is utilized to heat a process stream in said separation zone.

Claim 8

A process according to claim 1 wherein said hydrogeneration zone comprises a hydrogenation reactor which is operated at a temperature of about 200° to about 450° F. and a pressure of about 100° to about 500 psig.

Claim 9

A process according to claim 7 wherein said hydrogenation reactor releases heat at a temperature of about 250° F., which heat is utilized to reboil the bottoms liquid of a separation tower in said separation zone.

Claim 10

A process according to claim 7 wherein said hydrogenation reactor releases heat at a temperature of about 250° F., which heat is utilized to preheat said isobutane introduced into said isomerization zone.

Claim 11

A process according to claim 8 wherein said separation tower is operated at overhead temperatures of from about 100° to about 200° F. and overhead pressures of from about 55 to about 240 psig.

Claim 12

A process according to claim 7 wherein a liquid phase catalyst is employed in said hydrogenation reactor.

Claim 13

A process according to claim 11 wherein said liquid phase catalyst is a soluble homogeneous liquid phase hydrogenation catalyst.

Claim 14

A process according to claim 11 wherein a liquid reaction mass is withdrawn from said hydrogenation reactor and said reaction mass is utilized to reboil the bottoms liquid of a separation tower in said separation zone.

Claim 15

A process according to claim 7 wherein a heterogeneous phase hydrogenation catalyst is employed in said hydrogenation reactor.

Claim 16

A process according to claim 14 wherein said heterogeneous phase catalyst contains a material selected from the group consisting of palladium, platinum, nickel and chromium.

Claim 17

A process according to claim 14 wherein reactor effluent is discharged from said hydrogenation reactor and said reactor effluent is utilized to reboil the bottoms liquid of a separation tower in said separation zone.

Claim 18

A process according to claim 14 wherein reactor effluent is discharged from said hydrogenation reactor and said reactor effluent is treated in a scrubbing zone to remove high molecular weight compounds from said reactor effluent.

Claim 19

A process according to claim 1 wherein heat is generated in said hydrogenation zone and said heat is utilized to supply heat to said isomerization zone.

Claim 20

A process according to claim 1 wherein said isomerization zone includes an isomerization reactor which utilizes an isomerization catalyst.

Claim 21

A process according to claim 19 wherein said isomerization reactor is operated at a temperature of about 250° to about 950° F. and a pressure of about 250 to 700 psig.

Claim 22

A process according to claim 19 wherein said isomerization catalyst contains a material selected from the group consisting of aluminum chloride, aluminum bromide, noble metals and non-noble metals.

Claim 23

A process according to claim 1 wherein a stream of hydrogen is introduced into a normal and isobutane stream entering an isomerization reactor in said isomerization zone.

Claim 24

A process according to claim 22 wherein said hydrogen introduced into said normal butane and isobutane stream entering said isomerization reactor in said isomerization zone is obtaining from a demethanization zone of an ethylene production facility.

Claim 25

A process according to claim 1 further comprising: introducing a second stream of normal butane and isobutane into said separation zone to produce additional amounts of normal butane.

Claim 26

A process according to claim 1 further comprising: introducing a second stream of normal and isobutane into said isomerization zone to produce additional amounts of normal butane.

Claim 27

A process according to claim 1 further comprising: introducing a second stream of unsaturated C 4 hydrocarbons into said hydrogenation zone to produce additional amounts of normal butane.

Claim 28

A process according to claim 1 wherein a purge gas stream is withdrawn from said separation zone and said purge gas stream is introduced into a process stream of an ethylene production facility to separate and recover components of said purge gas stream.

Claim 29

A process according to claim 1 wherein said stream of unsaturated C 4 hydrocarbons comprises either: (i) a stream of unsaturated C 4 hydrocarbons from an ethylene production facility; (ii) a stream of unsaturated C 4 hydrocarbons from a butadiene extraction unit which unit derives its feed from an ethylene production facility, or (iii) any mixture of (i) and (ii).

Claim 30

A process according to claim 28 wherein said stream of unsaturated C 4 hydrocarbons also contains unsaturated C 4 hydrocarbons from another source.

Claim 31

A process according to claim 19 wherein the inlet temperature of the isomerization reactor is from about 250° to about 950° F. and the inlet pressure is from about 250 to about 700 psig.

Claim 32

A process according to claim 19 wherein the outlet temperature of the isomerization reactor is from about 210° to about 910° F. and the outlet pressure is from about 210 to about 660 psig.

Claim 33

A process according to claim 19 wherein said isomerization catalyst contains a support or base carrier which is comprised of a material selected from the group consisting of alumina, alumina-silica, alumina-boria, Y-type zeolite and Mordenite.

Claim 34

A process according to claim 22 wherein a hydrogen containing stream is separated from said normal and isobutane stream recovered from said isomerization zone and said hydrogen containing stream is introduced into said hydrogenation zone as a part of the hydrogen feed into said hydrogenation zone.

Claim 35

In a process for the production of ethylene by the pyrolytic cracking of hydrocarbons in a cracking zone to produce a process stream of cracked gases, introducing said process stream of cracked gases into a rapid cooling zone to cool said gases, passing said cooled process stream of cracked gases into a quench prefractionation and compression zone to further cool and compress said gases and remove heavy hydrocarbons, passing said process stream of compressed cracked gases through a demethanization zone wherein methane is removed from said process stream and a stream of hydrogen is generated, thereafter, directing said process stream of compressed cracked gases through a recovery zone wherein ethylene is recovered and a stream of butene raffinate is formed, the improvement comprising the steps of: a. introducing said stream of butene raffinate into a hydrogenation zone wherein said butene raffinate is passed in contact with said stream of hydrogen generated in said demethanization zone at temperatures of about 200° to about 450° F. and a pressure of about 100 to about 500 psig to form a stream consisting essentially of normal butane and isobutane; b. discharging said stream of normal butane and isobutane from said hydrogenation zone and introducing said discharged normal butane and isobutane stream into a separation zone to separate said normal butane from said isobutane in a separation tower which is operated at overhead temperatures of from about 100° to about 200° F. and overhead pressures of from about 55 to about 240 psig; c. discharging said normal butane from said separation zone and introducing said normal butane from said separation zone into said cracking zone as a feedback for the production of ethylene; d. passing said isobutane from said separation zone into an isomerization zone wherein a portion of said isobutane is converted into normal butane in the presence of an isomerization catalyst to form a stream of normal butane and isobutane; and e. thereafter, returning said stream of normal butane and isobutane produced in said isomerization zone into said separation zone to separate the normal butane produced in said isomerization zone.

Claim 36

In a process for the production of ethylene by the pyrolytic cracking of hydrocarbons in a cracking zone to produce a process stream of cracked gases, introducing said process stream of cracked gases into a rapid cooling zone to cool said gases, passing said cooled process stream of cracked gases into a quench prefractionation and compression zone to further cool and compress said gases and remove heavy hydrocarbons, passing said process stream of compressed cracked gases through a demethanization zone wherein methane is removed from said process stream and a stream of hydrogen is generated, thereafter, directing said process stream of compressed cracked gases through a recovery zone wherein ethylene is recovered and a stream of butene raffinate is formed, the improvement comprising the steps of: a. introducing said stream of butene raffinate into a hydrogenation zone wherein said butene raffinate is passed in contact with said stream of hydrogen generated in said demethanization zone at temperatures of about 200° to about 450° F. and a pressure of about 100 to about 500 psig to form a stream consisting essentially of normal butane and isobutane; b. discharging said stream of normal butane and isobutane from said hydrogenation zone and introducing said discharged normal butane and isobutane stream into a separation zone to separate said normal butane from said isobutane in a separation tower which is operated at overhead temperatures of from about 100° to about 200° F. and overhead pressures of from about 55 to about 240 psig; c. discharging said normal butane from said separation zone and introducing said normal butane from said separation zone into said cracking zone as a feedback for the production of ethylene; d. passing said isobutane from said separation zone into an isomerization zone wherein a portion of said isobutane is converted into normal butane in the presence of an isomerization catalyst to form a stream of normal butane and isobutane; and e. thereafter, returning said stream of normal butane and isobutane produced in said isomerization zone into said separation zone to separate the normal butane produced in said isomerization zone.

Claim 37

A process according to claim 34 wherein heat is generated in said hydrogenation zone which heat is utilized to separate said normal butane from said isobutane in said separation tower.

Claim 38

A process according to claim 34 wherein heat which is generated in said hydrogenation zone is utilized to preheat said isobutane entering said isomerization zone.