Method for producing high-efficiency methanol capable of reducing emission of carbon dioxide

Patent metadata

Field	Value
Publication number	US-2017362147-A1
Application number	US-201515502134-A
Country	US
Kind code	A1
Filing date	Jul 2, 2015
Priority date	Aug 4, 2014
Publication date	Dec 21, 2017
Grant date	—

Abstract

A method for producing high-efficiency methanol capable of reducing emission of carbon dioxide. The method includes: a first step of preparing mixed gas by using steam and natural gas as raw materials and converting C 2+ hydrocarbon contained in the natural gas into methane on a catalyst; a second step of preparing a synthesis gas including carbon monoxide, carbon dioxide, and hydrogen by reforming the mixed gas in a reformer filled with a reforming catalyst; and a third step of preparing methanol by using the synthesis gas as the raw material and reacting the synthesis gas.

First claim

1 . A method for producing methanol, the method comprising:
a first step of preparing mixed gas by using steam and natural gas as raw materials and converting C 2+ hydrocarbons contained in the natural gas into methane over a catalyst; a second step of preparing a synthesis gas including carbon monoxide, carbon dioxide, and hydrogen by reforming the mixed gas in a reformer filled with a reforming catalyst; and a third step of a methanol synthesis process, in which methanol is prepared by using the synthesis gas as a raw material and reacting the synthesis gas in a methanol synthesis reactor filled with a methanol synthesis catalyst, wherein the methanol product in the methanol synthesis process and unreacted synthesis gas are separated, some of the separated unreacted synthesis gas is supplied to a heating furnace, providing reaction heat required for the reformer of the second step and combusted together with the natural gas, and the mixed gas supplied to the reformer passes through a heat exchanger while post-combustion gas emitted from the heating furnace passes through the heat exchanger to supply the mixed gas heated through heat exchange with the post-combustion gas in the heat exchanger to the reformer.

2 . The method of claim 1 , wherein the carbon dioxide required for the methanol synthesis process is injected into any one of the reformer of the second step and the methanol synthesis reactor of the third step or is split to be injected into both of the reformer and the methanol synthesis reactor.

3 . The method of claim 2 , wherein the carbon dioxide is injected at a mole ratio of 0.1 to 0.4 with respect to the natural gas used as the raw material in the first step.

4 . The method of claim 1 , wherein some of residual unreacted synthesis gas other than the unreacted synthesis gas supplied to the heating furnace is simultaneously recirculated to the second step process and the third step process to be reused as the raw material for preparing the synthesis gas and synthesizing the methanol or recirculated only to the third step process to be reused as the raw material for synthesizing methanol.

5 . (canceled)

6 . The method of claim 2 , wherein when the carbon dioxide required for the methanol synthesis process is injected into the reformer of the second step, the carbon dioxide passes through the heat exchanger through which the post-combustion gas passes to supply the carbon dioxide heated through the heat exchange with the post-combustion gas in the heat exchanger to the reformer.

7 . The method of claim 1 , wherein the heat exchanger for increasing a temperature of the mixed gas includes
a first heat exchanger disposed at an upstream side based on a mixed gas supplying path and disposed at a downstream side based on a post-combustion gas path, and a second heat exchanger disposed at a downstream side based on the mixed gas supplying path and disposed at an upstream side based on the post-combustion gas path, wherein in supplying the carbon dioxide required for the methanol synthesis process, the carbon dioxide passes through the first heat exchanger to supply the carbon dioxide heated through the heat exchange with the post-combustion gas in the first heat exchanger to the reformer.

8 . (canceled)

9 . (canceled)

10 . The method of claim 1 , wherein while the post-combustion gas passes through a fifth heat exchanger, the natural gas and the steam as the raw materials supplied to a pre-reformer in which the mixed gas is prepared in the first step pass through the fifth heat exchanger to supply the raw materials heated through the heat exchange with the post-combustion gas in the fifth heat exchanger to the pre-reformer.

11 . The method of claim 10 , wherein a heat exchanger is additionally disposed at an upstream side of the fifth heat exchanger based on a post-combustion gas path, the heat exchanger controlling the temperature of the post-combustion gas through the heat exchange between the post-combustion gas and refrigerant by making at least one of water and the steam pass through the refrigerant while making the post-combustion gas pass through the heat exchanger.

12 . The method of claim 11 , wherein a sixth heat exchanger is additionally disposed at a downstream side of the fifth heat exchanger based on the post-combustion gas path, in which the post-combustion gas and the water exchange heat by making the water used as the refrigerant or the water supplied for supplying the steam pass while making the post-combustion gas pass.

13 . (canceled)

14 . The method of claim 1 , wherein while air for combustion, which is supplied to the heating furnace, passes through a seventh heat exchanger, the post-combustion gas passes through the seventh heat exchanger to supply the air for combustion, which is heated by heat exchange with the post-combustion gas in the seventh heat exchanger, to the hearing furnace.

15 . The method of claim 14 , wherein while the air for combustion, which is primarily heated by the seventh heat exchanger, passes through an eighth heat exchanger disposed at an upstream side of the seventh heat exchanger based on a post-combustion gas path, the post-combustion gas passes through the eighth heat exchanger to supply the air for combustion, which is additionally heated by the heat exchange with the post-combustion gas in the eighth heat exchanger, to the heating furnace.

16 . The method of claim 10 , wherein a heat exchanger is additionally disposed at a downstream side of the fifth heat exchanger based on a post-combustion gas path, the heat exchanger controlling the temperature of the post-combustion gas through the heat exchange between the post-combustion gas and refrigerant by making at least one of the water and the steam pass through the refrigerant while making the post-combustion gas pass through the heat exchanger.

17 . The method of claim 16 , wherein a sixth heat exchanger is additionally disposed at the downstream side of the heat exchanger, controlling the temperature of the post-combustion gas based on the post-combustion gas path, in which the post-combustion gas and the water exchange heat by making the water used as the refrigerant or the water supplied for supplying the steam pass while making the post-combustion gas pass.

18 . The method of claim 1 , wherein the mole ratio of H 2 /(2CO+3CO 2 ) in the synthesis gas introduced to the methanol synthesis reaction of the third step is controlled to be in the range of 0.9 to 1.5.

19 . The method of claim 1 , wherein the unreacted synthesis gas supplied- to the heating furnace to be combusted in the unreacted synthesis gas emitted in the methanol synthesis reaction of the third step is split so that a mole flow ratio of the unreacted synthesis gas supplied to the heating furnace to be combusted becomes 0.005 to 0.1 with respect to the entire unreacted synthesis gas.

20 . The method of claim 11 , wherein in the heat exchanger through which the post-combustion gas and the water pass, the steam produced through the heat exchange between the post-combustion gas and the water is used as the raw material of the first step.

21 - 23 . (canceled)

24 . The method of claim 1 , wherein the steam is produced by using the reaction heat generated in the methanol synthesis reaction of the third step for heating the water and the produced steam is used as the raw material in the first step.

25 - 27 . (canceled)

28 . The method of claim 1 , wherein

Assignees

• Korea Res Inst Chemical Tech

Inventors

• Jun Ki Won
• Choi In Hyuck
• Zhang chun dong

Classifications

• C01B2203/061

  Methanol production · CPC title

• C07C4/06

  Catalytic processes {(C07C4/025 takes precedence)} · CPC title

• C07C31/04

  Methanol · CPC title

• C07C4/02

  by cracking a single hydrocarbon or a mixture of individually defined hydrocarbons or a normally gaseous hydrocarbon fraction · CPC title

• C01B3/38

  using catalysts · CPC title