Oxidative dehydrogenation of ethane using carbon dioxide

Patent metadata

Field	Value
Publication number	US-10662127-B2
Application number	US-201816113772-A
Country	US
Kind code	B2
Filing date	Aug 27, 2018
Priority date	Aug 28, 2017
Publication date	May 26, 2020
Grant date	May 26, 2020

Abstract

The present disclosure relates to methods and systems suitable for chemical production by dehydrogenation of ethane utilizing carbon dioxide as a soft oxidant. Ethane and carbon dioxide are reacted in a catalytic reactor to produce a reaction product stream comprising at least ethylene and carbon dioxide. The carbon dioxide can be separated for recycling back into the catalytic reactor, and the ethylene can be upgraded using a variety of process units. Heat from the reaction product stream can be recycle for further uses, including reducing the amount of added heating needed in the catalytic reactor. Additional materials, such carbon monoxide, hydrogen, syngas, methanol, methane, ethane, and even heavier hydrocarbons can be provided.

First claim

The invention claimed is:

1. A method for chemical production from ethane, the method comprising:
providing ethane and carbon dioxide into a reactor at a molar ratio so that the amount of provided carbon dioxide is in excess of the stoichiometrically required amount for complete reaction with the ethane;
reacting the ethane with the carbon dioxide in the reactor in the presence of a catalyst to form a reaction product stream comprising at least ethylene, water, and carbon dioxide, the reaction product stream being at a temperature of about 450° C. or greater;
passing the reaction product stream through a primary heat exchanger to withdraw heat therefrom;
removing water and optionally any further condensates present in the reaction product stream;
compressing the reaction product stream to a pressure of at least 20 bar;
separating carbon dioxide from the reaction product stream in a separation unit to provide an upgraded stream comprising ethylene;
heating at least a portion of the carbon dioxide separated from the reaction product stream using the heat withdrawn from the reaction product stream to form a stream of heated carbon dioxide;
recycling the stream of heated carbon dioxide back into the reactor; and
further processing the upgraded stream comprising ethylene to provide at least ethylene as a produced chemical.

2. The method of claim 1 , wherein the reactor is a fixed bed reactor, a catalytic reactor, or a fluidized bed catalytic reactor.

3. The method of claim 1 , wherein the reaction product stream is at a temperature of about 500° C. to about 800° C.

4. The method of claim 1 , wherein the reaction product stream comprises at least 10% by mass carbon dioxide based on the total mass of the reaction product exiting the reactor.

5. The method of claim 1 , wherein the reaction product stream comprises about 10% to about 60% by mass carbon dioxide, based on the total mass of the reaction product exiting the reactor.

6. The method of claim 1 , wherein the primary heat exchanger is a transfer line exchanger (TLE).

7. The method of claim 1 , wherein the reaction product stream exiting the primary heat exchanger is at a temperature of about 200° C. to about 400° C.

8. The method of claim 1 , wherein removing water and optionally any further condensates present in the reaction product comprises passing the reaction product stream through a condensing unit.

9. The method of claim 8 , wherein the reaction product stream is cooled in the condensing unit to about ambient temperature.

10. The method of claim 1 , wherein heating at least a portion of the carbon dioxide separated from the reaction product stream using the heat withdrawn from the reaction product stream comprises passing the carbon dioxide through a secondary heat exchanger against a circulating stream that is heated in the primary heat exchanger using the heat withdrawn from the reaction product stream.

11. The method of claim 1 , wherein recycling the stream of heated carbon dioxide back into the reactor comprises one or more of the following:
injecting the stream of heated carbon dioxide directly into the reactor;
injecting the stream of heated carbon dioxide into a carbon dioxide source;
injecting the stream of heated carbon dioxide into a line delivering carbon dioxide from a carbon dioxide source to the reactor;
injecting the stream of heated carbon dioxide into an ethane source;
injecting the stream of heated carbon dioxide into a line delivering ethane from an ethane source to the reactor.

12. The method of claim 1 , wherein the at least a portion of the stream of heated carbon dioxide is passed through a line heater configured for transfer of heat from the stream of heated carbon dioxide to one or more streams being passed into the reactor.

13. The method of claim 1 , wherein a portion of the heat withdrawn from the reaction product stream in the primary heat exchanger is used for heating one or more of the following:
the reactor;
a carbon dioxide source;
a carbon dioxide line delivering carbon dioxide from a carbon dioxide source to the reactor;
an ethane source;
an ethane line delivering ethane from an ethane source to the reactor.

14. The method of claim 1 , wherein a portion of the heat withdrawn from the reaction product stream in the primary heat exchanger is used for heating one or both of a pressurized steam stream and a pressurized CO 2 stream for use in power generation in a closed loop or semi-open loop power production system wherein a working stream is repeatedly compressed and expanded for power production.

15. The method of claim 1 , wherein a portion of the heat withdrawn from the reaction product stream in the primary heat exchanger is used for heating a steam stream that is injected into the reactor.

16. The method of claim 1 , wherein further processing the upgraded ethylene stream comprises one or more of the following steps:
passing the upgraded ethylene stream through an adsorber to adsorb any water in the upgraded ethylene stream;
passing the upgraded ethylene stream through a refrigeration unit to cool the upgraded ethylene stream to a temperature of less than −50° C.;
passing the upgraded ethylene stream through a de-methanizer unit;
passing the upgraded ethylene stream through a de-ethanizer unit to produce a mixture of ethane and ethylene, and passing the mixture of ethane and ethylene from the de-ethanizer unit into a C 2 splitter unit.

17. The method of claim 1 , comprising injecting steam into the reactor.

18. A system for chemical production from ethane, the system comprising:
a catalytic reactor configured for reacting ethane with carbon dioxide at a temperature of about 450° C. or greater to form a reaction product stream including at least ethylene and carbon dioxide;
an ethane line configured for delivery of ethane into the catalytic reactor;
a carbon dioxide line configured for delivery of carbon dioxide into the catalytic reactor;
a primary heat exchanger configured to receive the reaction product stream from the catalytic reactor and withdraw heat therefrom;
a gas-liquid separation unit configured for removal of water and optionally other condensates from the reaction product stream;
a compressor configured for compressing the reaction product stream to a pressure of at least 20 bars;
a carbon dioxide separation unit configured for receiving the reaction product stream after at least one stage of compression and for separating at least a portion of the carbon dioxide from the reaction product stream to provide an upgraded stream comprising ethylene; and
a line configured for delivering at least a portion of the carbon dioxide separated from the reaction product stream in the carbon dioxide separation unit to the reactor while being heated with at least a portion of the heat withdrawn from the reaction product stream in the primary heat exchanger.

19. The system of claim 18 , comprising a secondary heat exchanger, wherein the line configured for delivering at least a portion of the carbon dioxide separated from the reaction product stream in the carbon dioxide separation unit to the reactor passes through the secondary heat exchanger for heating against a line passing a heated circulating stream from the primary heat exchanger.

20. The system of claim 18 , comprising a line heater configured for heating one or both of the ethane line and the carbon dioxide line.

21. The system of claim 20 , comprising one or more lines configured for delivering a heated

Assignees

• 8 Rivers Capital Llc

Inventors

• Beauchamp Damian
• Lu Xijia
• Rafati Mohammad

Classifications

• C07C5/333 Primary

  Catalytic processes · CPC title

• B01J8/08

  with moving particles (with fluidised particles B01J8/18) · CPC title

• B01J8/02

  with stationary particles, e.g. in fixed beds · CPC title

• C07C11/04

  Ethene · CPC title

• C07C5/42 Primary

  by dehydrogenation with a hydrogen acceptor · CPC title