Method for selective hydrogenation of butadiene extraction tail gas and selective hydrogenation apparatus thereof

Patent metadata

Field	Value
Publication number	US-12570908-B2
Application number	US-202118033871-A
Country	US
Kind code	B2
Filing date	Oct 19, 2021
Priority date	Oct 26, 2020
Publication date	Mar 10, 2026
Grant date	Mar 10, 2026

Abstract

The present invention belongs to the field of petrochemical industry, and discloses a method for selective hydrogenation of butadiene extraction tail gas and a selective hydrogenation apparatus thereof. The method for selective hydrogenation of butadiene extraction tail gas comprises: (1) an alkyne-containing tail gas from a butadiene extraction unit is fed into a raw material tank, optionally impurities entrained in the alkyne-containing tail gas are removed before being fed into the raw material tank; (2) a C4 raw material in the raw material tank is pressurized by a feed pump to a pressure required for reaction, then merged with a circulated C4 stream from a first-stage reactor outlet buffer tank and fed into a first-stage mixer, wherein it is mixed with hydrogen gas, and fed into the first-stage reactor to undergo a first-stage hydrogenation reaction, and a first-stage reaction stream obtained by the reaction is fed into the first-stage reactor outlet buffer tank; the hydrogen gas required for the reaction in the first-stage reactor is fed through a first feeding mode or a second feeding mode: the first feeding mode comprises: all the hydrogen gas required for the reaction is fed through the first-stage reactor outlet buffer tank, and then fed into the first-stage reactor through a first route at an outlet of the first-stage reactor outlet buffer tank; the second feeding mode comprises: a part of the hydrogen gas required for the reaction is fed through the first-stage reactor outlet buffer tank, and then fed into the first-stage reactor through the first route at an outlet of the first-stage reactor outlet buffer tank; and the other part of the hydrogen gas is fed through the first-stage mixer, and then fed into the first-stage reactor; (3) there is no gas-phase discharge from the first-stage reactor outlet buffer tank, and a liquid-phase product is divided into at least two streams, the first stream is returned to the first-stage reactor as the circulated C4 stream, and the second stream is used as a feed to a stabilization tower or subjected to further hydrotreatment prior to being fed into the stabilization tower; (4) a C4 hydrogenation product is recovered after separation in the stabilization tower.

First claim

The invention claimed is:

1 . A method for selective hydrogenation of butadiene extraction tail gas, comprising:
operation (1) feeding an alkyne-containing tail gas from a butadiene extraction unit into a raw material tank, and optionally removing impurities entrained in the alkyne-containing tail gas before being fed into the raw material tank; operation (2) pressuring a C4 raw material in the raw material tank by a feed pump to a pressure required for reaction, then merging the C4 raw material with a circulated C4 stream from a first-stage reactor outlet buffer tank and feeding the merged stream into a first-stage mixer, mixing the merged stream with hydrogen gas in the first-stage mixer, and feeding the mixture into the first-stage reactor to undergo a first-stage hydrogenation reaction to obtain a first-stage reaction stream, and feeding the first-stage reaction stream into the first-stage reactor outlet buffer tank; wherein the hydrogen gas required for the reaction in the first-stage reactor is fed through a first feeding mode or a second feeding mode: wherein the first feeding mode comprises: feeding all the hydrogen gas required for the reaction through the first-stage reactor outlet buffer tank, and then into the first-stage reactor through a first route at an outlet of the first-stage reactor outlet buffer tank; wherein the second feeding mode comprises: feeding a part of the hydrogen gas required for the reaction through the first-stage reactor outlet buffer tank, and then into the first-stage reactor through the first route at an outlet of the first-stage reactor outlet buffer tank; and feeding the other part of the hydrogen gas through the first-stage mixer, and then into the first-stage reactor; operation (3) dividing a liquid-phase product obtained from the first-stage reactor outlet buffer tank into at least two streams, wherein there is no gas-phase discharge from the first-stage reactor outlet buffer tank, wherein the first stream is returned to the first-stage reactor as the circulated C4 stream, and the second stream is used as a feed to a stabilization tower or subjected to further hydrotreatment prior to being fed into the stabilization tower; operation (4) recovering a C4 hydrogenation product after separation in the stabilization tower.

2 . The method for selective hydrogenation of butadiene extraction tail gas according to claim 1 , wherein, in operation (1), the alkyne-containing tail gas is diluted with a side-draw diluent C4 stream from the stabilization tower; or wherein, in operation (1), the alkyne-containing tail gas is diluted with a diluent C4 stream from the first-stage reactor outlet buffer tank.

3 . The method for selective hydrogenation of butadiene extraction tail gas according to claim 1 , wherein, in operation (2), in the second feeding mode, the mass ratio of the part of the hydrogen gas required for the reaction to the hydrogen gas required for the first-stage hydrogenation reaction is not less than 0.3, and the hydrogen gas required for the first-stage hydrogenation reaction is the sum of the part of the hydrogen gas required for the reaction and the other part of the hydrogen gas.

4 . The method for selective hydrogenation of butadiene extraction tail gas according to claim 1 , wherein, in operation (3), the further hydrotreatment of the second stream prior to being fed into the stabilization tower comprises: feeding the second stream into a second-stage reactor as a feed through a second-stage feed cooler and a second-stage mixer to carry out a second-stage hydrogenation reaction, and then a second-stage reaction stream obtained by the reaction in the second-stage reactor passing through a second-stage reactor outlet buffer tank and entering the stabilization tower.

5 . The method for selective hydrogenation of butadiene extraction tail gas according to claim 4 , wherein, in operation (3), the hydrogen gas required for the reaction in the second-stage reactor is fed through a third feeding mode or a fourth feeding mode;
wherein the third feeding mode comprises: feeding all the hydrogen gas required for the reaction through the first-stage reactor outlet buffer tank, and then into the second-stage reactor through a second route at the outlet of the first-stage reactor outlet buffer tank; wherein the fourth feeding mode comprises: feeding a part of the hydrogen gas required for the reaction through the first-stage reactor outlet buffer tank, and then into the second-stage reactor through the second route at the outlet of the first-stage reactor outlet buffer tank; and feeding the other part of the hydrogen gas through the second-stage mixer, and then into the second-stage reactor.

6 . The method for selective hydrogenation of butadiene extraction tail gas according to claim 5 , wherein, in operation (3), in the fourth feeding mode, the mass ratio of the part of the hydrogen gas required for the reaction to the hydrogen gas required for the second-stage hydrogenation reaction is not less than 0.3, and wherein the hydrogen gas required for the second-stage hydrogenation reaction is the sum of the part of the hydrogen gas required for the reaction and the other part of the hydrogen gas.

7 . The method for selective hydrogenation of butadiene extraction tail gas according to claim 1 , wherein, in operation (1), the raw material tank has an operating pressure ranging from 0.1 MPaG to 1.0 MPaG; and/or
wherein, in operation (2), the C4 raw material in the raw material tank is pressurized to a pressure ranging from 1.0 MPaG to 4.0 MPaG by the feed pump, and the mass flow ratio of the circulated C4 stream to the raw material is 5-30:1; the first-stage reactor has an inlet temperature ranging from 5° C. to 60° C., and a liquid space velocity ranging from 1h −1 to 50h −1 ; the first-stage reactor has a pressure that is controlled by a pressure-compensating hydrogen gas of the first-stage reactor outlet buffer tank, and the reaction pressure ranges from 1.0 MPaG to 4.0 MPaG; and/or wherein, in operation (4), the stabilization tower has an operating pressure ranging from 0.4 MPaG to 1.2 MPaG, a theoretical plate number ranging from 10 to 40, and a side-draw theoretical plate position at 5 to 35.

8 . The method for selective hydrogenation of butadiene extraction tail gas according to claim 1 , wherein, in operation (1), the alkyne-containing tail gas from the butadiene extraction unit is fed into the raw material tank without removing the impurities from the alkyne-containing tail gas;
in operation (3), the liquid-phase product from the first-stage reactor outlet buffer tank are divided into at least two streams, wherein there is no gas-phase discharge from the first-stage reactor outlet buffer tank, wherein the first stream is returned to the first-stage reactor as the circulated C4 stream, and the second stream is used as a feed to the stabilization tower; in operation (4), the first-stage reaction stream obtained from the reaction in the first-stage reactor is fed into the stabilization tower through the first-stage reactor outlet buffer tank, and separated by the stabilization tower to recover a C4 hydrogenation product.

9 . The method for selective hydrogenation of butadiene extraction tail gas according to claim 8 , wherein,
in operation (1), the alkyne-containing tail gas is diluted with a side-draw diluent C4 stream from the stabilization tower; and/or in operation (1), the raw material tank has an operating pressure ranging from 0.5 MPaG to 1.0 MPaG; in operation (2), the diluted C4 raw material is pressurized by the feed pump to a pressure ranging from 1.0 MPaG to 4.0 MPaG, and the mass flow ratio of the circulated C4 stream to the diluted C4 raw material is 5-30:1; the first

Assignees

• China Petroleum & Chem Corp
• Beijing Res Inst Chemical Ind China Petroleum & Chemical Corp

Inventors

• Li Yan
• Tian Jun
• Li Dongfeng
• Guo Liang
• Li Chunfang
• Yue Yi
• Du Zhou
• Shu Zhan
• Luo Shujuan
• Ye Jieming
• Cui Ting

Classifications

• C10G2300/802

  Diluents · CPC title

• C10G2300/4018

  Spatial velocity, e.g. LHSV, WHSV · CPC title

• C10G2300/4012

  Pressure · CPC title

• C10G2300/4006

  Temperature · CPC title

• C10G2300/1092

  C2-C4 olefins · CPC title