Aromatic hydrocarbon alkylation process product recovery method

Claim 2

A process for the production of an alkylaromatic hydrocarbon which comprises contacting a feed acyclic olefinic hydrocarbon and a feed aromatic hydrocarbon with an alkylation catalyst in an alkylation reaction zone maintained at alkylation-promoting conditions and producing a reaction zone effluent stream comprising the feed aromatic hydrocarbon, a product alkylaromatic hydrocarbon and high-boiling by-product hydrocarbons and subsequently recovering the product alkylaromatic hydrocarbon by a method which comprises the steps of: (a) passing a process stream comprising the feed aromatic hydrocarbon, the product alkylaromatic hydrocarbon and the by-product hydrocarbons into a recycle fractionation column operated at conditions which effect the separation of entering hydrocarbons into at least a net overhead stream, which is rich in the feed aromatic hydrocarbon, and a first bottoms stream, which comprises the product alkylaromatic hydrocarbon and the by-product hydrocarbons; (b) passing the first bottoms stream into a product fractionation column operated at conditions effective to separate entering hydrocarbons into a first overhead vapor stream, which is rich in the product alkylaromatic hydrocarbon, and a second bottoms stream, which is rich in the product alkylaromatic hydrocarbon and also comprises the by-product hydrocarbons; (c) at least partially condensing the first overhead vapor stream in a reboiler means supplying heat to a lower portion of the recycle column, withdrawing a first portion of the resultant condensate from the process as a net product stream and returning a second portion of the condensate to the product column as reflux liquid; (d) passing the second bottoms stream into a stripping column operated at fractional distillation conditions, including a lower pressure than is maintained in the product fractionation column, and effective to separate entering hydrocarbons into a second overhead vapor stream comprising the product alkylaromatic hydrocarbon and a third bottoms stream, which comprises the by-product hydrocarbons and is substantially free of the product alkylaromatic hydrocarbon; and, (e) compressing the second overhead vapor stream and then passing the second overhead vapor stream into the product fractionation column.

Claim 3

The process of claim 1 further characterized in that the stripping column is operated at a pressure at least 15 psi lower than the pressure at which the product fractionation column is operated.

Claim 4

The process of claim 2 further characterized in that the second overhead vapor stream is passed into a lower portion of the product fractionation column.

Claim 5

The process of claim 1 further characterized in that the feed aromatic hydrocarbon is toluene.

Claim 6

The process of claim 4 further characterized in that the feed acyclic olefinic hydrocarbon is a C 3 to C 5 hydrocarbon.

Claim 7

The process of claim 5 further characterized in that the feed acyclic olefinic hydrocarbon is propylene.

Claim 8

The process of claim 1 further characterized in that the feed aromatic hydrocarbon is benzene.

Claim 9

The process of claim 7 further characterized in that the feed acyclic olefinic hydrocarbon is propylene.

Claim 10

The process of claim 7 further characterized in that the product alkylaromatic hydrocarbon is a bialkylaromatic hydrocarbon.

Claim 11

The process of claim 1 further characterized in that the alkylation catalyst comprises a crystalline aluminosilicate.

Claim 12

The process of claim 1 further characterized in that the alkylation catalyst is a solid phosphoric acid type catalyst.

Claim 13

A process for the production of an alkylaromatic hydrocarbon which comprises contacting a feed acyclic olefinic hydrocarbon and a feed aromatic hydrocarbon with a solid alkylation catalyst in an alkylation reaction zone maintained at alkylation-promoting conditions and producing a reaction zone effluent stream comprising the feed aromatic hydrocarbon, a monoalkylaromatic product hydrocarbon and high-boiling by-product hydrocarbons and subsequently recovering the product alkylaromatic hydrocarbon by a method which comprises the steps of: (a) passing a process stream comprising the feed aromatic hydrocarbon, the monoalkylaromatic product hydrocarbon and the by-product hydrocarbons into a recycle fractionation column operated at conditions which effect the separation of entering hydrocarbons into at least a net overhead stream, which is rich in the feed aromatic hydrocarbon, and a first bottoms stream, which comprises the product hydrocarbon and the by-product hydrocarbons; (b) passing the first bottoms stream into a product fractionation column operated at conditions effective to separate entering hydrocarbons into a first overhead vapor stream, which is rich in the product hydrocarbon and substantially free of the by-product hydrocarbons, and a second bottoms stream, which is rich in the product hydrocarbon and also comprises the by-product hydrocarbons; (c) at least partially condensing the first overhead vapor stream in a reboiler means supplying heat to the bottom portion of the recycle column, withdrawing a first portion of the resultant condensate from the process as a net product stream and returning a second portion of the condensate to the product column as reflux liquid; (d) passing the second bottoms stream into a stripping column operated at fractional distillation conditions, including a pressure which is at least 20 psi lower than is maintained in the product fractionation column, and effective to separate entering hydrocarbons into a second overhead vapor stream comprising the product alkylaromatic hydrocarbon and a third bottoms stream, which comprises the by-product hydrocarbons and is substantially free of the product hydrocarbon; and, (e) compressing the second overhead vapor stream and then passing the second overhead vapor stream into a bottom portion of the product fractionation column.

Claim 14

A process for the production of an alkylaromatic hydrocarbon which comprises contacting a feed acyclic olefinic hydrocarbon and a feed aromatic hydrocarbon with a solid alkylation catalyst in an alkylation reaction zone maintained at alkylation-promoting conditions and producing a reaction zone effluent stream comprising the feed aromatic hydrocarbon, a monoalkylaromatic product hydrocarbon and high-boiling by-product hydrocarbons and subsequently recovering the product alkylaromatic hydrocarbon by a method which comprises the steps of: (a) passing a process stream comprising the feed aromatic hydrocarbon, the monoalkylaromatic product hydrocarbon and the by-product hydrocarbons into a recycle fractionation column operated at conditions which effect the separation of entering hydrocarbons into at least a net overhead stream, which is rich in the feed aromatic hydrocarbon, and a first bottoms stream, which comprises the product hydrocarbon and the by-product hydrocarbons; (b) passing the first bottoms stream into a product fractionation column operated at conditions effective to separate entering hydrocarbons into a first overhead vapor stream, which is rich in the product hydrocarbon and substantially free of the by-product hydrocarbons, and a second bottoms stream, which is rich in the product hydrocarbon and also comprises the by-product hydrocarbons; (c) at least partially condensing the first overhead vapor stream in a reboiler means supplying heat to the bottom portion of the recycle column, withdrawing a first portion of the resultant condensate from the process as a net product stream and returning a second portion of the condensate to the product column as reflux liquid; (d) passing the second bottoms stream into a stripping column operated at fractional distillation conditions, including a pressure which is at least 20 psi lower than is maintained in the product fractionation column, and effective to separate entering hydrocarbons into a second overhead vapor stream comprising the product alkylaromatic hydrocarbon and a third bottoms stream, which comprises the by-product hydrocarbons and is substantially free of the product hydrocarbon; and, (e) compressing the second overhead vapor stream and then passing the second overhead vapor stream into a bottom portion of the product fractionation column.

Claim 15

The process of claim 12 further characterized in that the feed aromatic hydrocarbon is benzene.

Claim 16

The process of claim 13 further characterized in that the feed acyclic olefinic hydrocarbon is a C 3 to C 5 hydrocarbon.

Claim 17

The process of claim 14 further characterized in that the feed acyclic olefinic hydrocarbon is propylene.

Claim 18

The process of claim 12 further characterized in that the alkylation catalyst comprises a crystalline aluminosilicate.

Claim 19

The process of claim 12 further characterized in that the alkylation catalyst is a solid phosphoric acid type catalyst.