Energy saving method and apparatus for preparing styrene and alpha-methylstyrene concurrently

Patent metadata

Field	Value
Publication number	US-10322982-B2
Application number	US-201615760899-A
Country	US
Kind code	B2
Filing date	Dec 7, 2016
Priority date	Dec 22, 2015
Publication date	Jun 18, 2019
Grant date	Jun 18, 2019

Abstract

The present invention relates to energy saving method and apparatus for preparing styrene and alpha-methylstyrene concurrently, by which economic feasibility may be improved by reusing energy during preparing styrene and alpha-methylstyrene concurrently.

First claim

The invention claimed is:

1. A method for preparing styrene and alpha-methylstyrene concurrently, the method comprising:
(a) a step of performing dehydrogenation reaction of ethylbenzene and cumene in the presence of a catalyst;
(b) a step of recovering heat from a reaction product by the reaction;
(c) a step of separating a gas phase from at least a portion of a reaction product undergone step (b) and sending thereof to a compression part, separating condensing water including water from a liquid phase, and recovering a fraction including styrene and alpha-methylstyrene;
(d) a step of compressing and cooling at least a portion of a gas phase among reaction products undergone step (c) to separate components having a low boiling point including hydrogen and carbon dioxide as a gas phase, and recycle a liquid phase including styrene, alpha-methylstyrene, ethylbenzene and cumene to step (c);
(e) a step of distilling and separating at least a portion of the fraction including styrene and alpha-methylstyrene, which is recover in step (c), into a fraction including styrene and a fraction including unreacted cumene;
(f) a step of recovering styrene from at least a portion of the fraction including styrene of step (e) and distilling and separating the fraction including unreacted ethylbenzene;
(g) a step of recovering ethylbenzene from at least a portion of the fraction including unreacted ethylbenzene of step (f) and recycling to a reaction part, and distilling and separating the fraction including benzene and toluene;
(h) a step of recovering cumene from at least a portion of the fraction including unreacted cumene of step (e) and recycling the recovered cumene to a reaction part, and distilling and separating a fraction including alpha-methylstyrene; and
(i) a step of recovering alpha-methylstyrene from at least a portion of the fraction including alpha-methylstyrene of step (h), and distilling and separating a fraction including a remaining component having a high boiling point,
wherein at least one of energy used during the distilling and separating in step (e) and energy used during the distilling and separating in step (h) is recovered to use for the vaporization of ethylbenzene and cumene of step (a) or as a heat source of a preparation process.

2. The method for preparing styrene and alpha-methylstyrene concurrently of claim 1 , wherein energy used during the distilling and separating in step (e) and energy used during the distilling and separating in step (h) are heat used for condensation.

3. The method for preparing styrene and alpha-methylstyrene concurrently of claim 1 , wherein the distilling in step (e) is performed at 120° C. or less.

4. The method for preparing styrene and alpha-methylstyrene concurrently of claim 1 , wherein energy used for the distilling and separating in step (e) is used for the vaporization of ethylbenzene and cumene, which is performed at 100° C. or less.

5. The method for preparing styrene and alpha-methylstyrene concurrently of claim 1 , wherein energy used for the distilling and separating in step (h) is used for the distillation in step (f), which is performed at 120° C. or less.

6. The method for preparing styrene and alpha-methylstyrene concurrently of claim 1 , wherein the vaporization of ethylbenzene and cumene is performed by further supplying steam.

7. The method for preparing styrene and alpha-methylstyrene concurrently of claim 1 , wherein the ratio of ethylbenzene and cumene used for the dehydrogenation reaction is 0.1-10:1 by weight.

8. The method for preparing styrene and alpha-methylstyrene concurrently of claim 1 , wherein the dehydrogenation reaction is performed at a temperature of 300 to 800° C.

9. The method for preparing styrene and alpha-methylstyrene concurrently of claim 1 , wherein the reaction product of step (b) is cooled to 15 to 60° C.

10. The method for preparing styrene and alpha-methylstyrene concurrently of claim 1 , wherein the reaction product of step (d) is compressed until a pressure reaches 1.5 to 5.5 KCA.

11. An apparatus for preparing styrene and alpha-methylstyrene concurrently, the apparatus comprising:
a reactor for performing dehydrogenation reaction of ethylbenzene and cumene in the presence of catalyst;
a heat exchanger for recovering heat from a reaction product from the reaction;
a decanter for separating a gas phase from at least a portion of a reaction product from which heat is recovered and sending thereof to a compression part, for separating condensing water including water from a liquid phase, and for recovering a fraction including styrene and alpha-methylstyrene;
a compression part composed of a compressor, a heat exchanger and a drum, for compressing and cooling at least a portion of the separated gas phase to separate components having a low boiling point including hydrogen and carbon dioxide as a gas phase, and for recovering a liquid phase including styrene, alpha-methylstyrene, ethylbenzene and cumene;
an SM/CM separation column for distilling and separating at least a portion of the fraction including styrene and alpha-methylstyrene, supplied from the decanter into a fraction including styrene and a fraction including unreacted cumene;
an EB/SM separation column for recovering styrene from at least a portion of the fraction including styrene separated from the SM/CM separation column, and distilling and separating a fraction including unreacted ethylbenzene;
an EB purification column for recovering ethylbenzene from at least a portion of the fraction including unreacted ethylbenzene, separated from the EB/SM separation column and recycling the recovered ethylbenzene to the reactor, and distilling and separating a fraction including benzene and toluene;
a CM/AMS separation column for recovering cumene from at least a portion of the fraction including unreacted cumene, separated from the SM/CM separation column, and recycling the recovered cumene to the reactor, and distilling and separating a fraction including alpha-methylstyrene;
an AMS purification column for recovering alpha-methylstyrene from at least a portion of the fraction including alpha-methylstyrene, separated from the CM/AMS separation column, and distilling and separating a fraction including a remaining component having a high boiling point;
an EB vaporizer for receiving energy used in the SM/CM separation column and the CM/AMS separation column, and for using the energy for the vaporization of ethylbenzene which undergoes dehydrogenation reaction in the reactor or for using as a heat source of a preparation process; and
a CM vaporizer for receiving energy used in the SM/CM separation column and the CM/AMS separation column, and for using for the vaporization of cumene which undergoes dehydrogenation reaction in the reactor or for using as a heat source of a preparation process.

12. The apparatus for preparing styrene and alpha-methylstyrene concurrently of claim 11 , wherein the energy used in the SM/CM separation column and the CM/AMS separation column is heat used in each condenser of the SM/CM separation column and the CM/AMS separation column.

13. The apparatus for preparing styrene and alpha-methylstyrene concurrently of claim 11 , wherein the distilling of the SM/CM separation column is performed at 120° C. or less.

14. The apparatus for preparing styrene and alpha-methylstyrene concurrently of claim 11 , wherein the energy used in the SM/CM separation column is supplied to the EB vaporizer and the CM vaporizer, which are operated at 100° C. or less.

15. The apparatus for preparing styrene and alpha-methylstyrene concurrently of claim 11 ,

Assignees

• Lg Chemical Ltd

Inventors

• Kim Mi-Kyung
• Lee Jae-Ik
• Lee Jong-Ku
• Lee Jeong-Seok

Classifications

• B01J23/31

  combined with bismuth · CPC title

• C07C2523/16

  of arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium · CPC title

• C07C2523/10

  of rare earths · CPC title

• Y02P20/51

  Cross-Sectional Technologies · mapped topic

• C07C2523/70

  of the iron group metals or copper · CPC title