Method for separating dimethyl carbonate

A technology for dimethyl carbonate and methyl formate, applied in the field of separation of dimethyl carbonate, can solve the problems of low ethylene glycol extraction efficiency, increased circulating amount of mixed liquid, and small amount of effectively separated DMC.

Active Publication Date: 2017-01-04
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the double-tower pressure swing rectification process does not need to add extractant, it needs two rectification towers to carry out the separation operation continuously, and the obtained high-concentration DMC yield is low, and the azeotrope of MeOH and DMC extracted at the top of the DMC separation tower is still low. It needs to be sent to the atmospheric tower to continue separation, so that the total amount of azeotrope at the top of the tower in the atmospheric tower and DMC separation tower increases, and the amount of effective separation of DMC is small, which increases energy consumption
CN101381309B separates DMC from the DMC-MeOH mixed solution by vacuum azeotropic rectification-pressurized azeotropic rectification double-tower process, and makes MeOH reclaimed, recycles, and this method needs vacuuming equipment, and does not carry out effective Heat integration, high energy consumption
However, researchers believe that the extraction efficiency of ethylene glycol is low, and it is not suitable for the extraction agent of DMC-MeOH mix

Method used

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  • Method for separating dimethyl carbonate
  • Method for separating dimethyl carbonate

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] Oxygen is fed to 1, and the coupling unit is recycle gas (containing methanol, dimethyl carbonate, methyl formate, methyl nitrite, CO, NO and N 2 ) and supplemented NO stream 2, CO feed 3 and methanol feed 4 are sent to the oxidative esterification reactor R100 for oxidative esterification, and the gaseous methyl nitrite stream 5 is obtained at the top of the tower, and the tower still obtains methyl nitrite containing The stream 6 of ester, dimethyl carbonate, methyl formate, methanol, nitric acid and water; the stream 6 is sent to the weight-removing tower T101 for separation, and the mixture containing methyl nitrite, dimethyl carbonate, and methyl formate is obtained at the top of the tower and the first light component stream 7 of methanol, obtain the first heavy component stream 8 containing nitric acid and water in the tower still; stream 8 is sent to the nitric acid concentration unit (not involved in this patent) and recycles after thickening, and stream 7 is se...

Embodiment 2

[0051] The embodiment is the same as [Example 1], except that the feed composition and the process parameters of each tower are different.

[0052] Oxygen stream 1 flow rate 2500Nm 3 / h, the purity is 99.8%, the rest is N 2 , Feeding in three stages. Coupling unit to recycle gas (containing methanol, dimethyl carbonate, methyl formate, methyl nitrite, CO, NO and N 2 ) and the flow rate of logistics 2 supplemented with NO is 80000Nm 3 / h, the composition is methanol 5%, dimethyl carbonate 0.5%, methyl formate 0.45%, methyl nitrite 8%, CO 5%, NO 15%, and the rest is N 2 , CO feed 3 flow rate is 9800Nm 3 / h, purity 99.5%, H 2 500ppm, and methanol feed 4 flow rate is 12500kg / h, purity 99.9%.

[0053] The reaction temperature of the oxidative esterification reactor is 83° C., and the reaction pressure is 0.6 MPag.

[0054] The theoretical plate number of the weight removal tower is 60, the operating pressure at the top of the tower is 500kPaG, and the temperature at the top ...

Embodiment 3

[0062] The embodiment is the same as [Example 1], except that the feed composition and the process parameters of each tower are different.

[0063] Oxygen stream 1 flow rate 2500Nm 3 / h, the purity is 99.8%, the rest is N 2, Feeding in three stages. Coupling unit to recycle gas (containing methanol, dimethyl carbonate, methyl formate, methyl nitrite, CO, NO and N 2 ) and the flow rate of logistics 2 supplemented with NO is 140000Nm 3 / h, the composition is methanol 10%, dimethyl carbonate 0.12%, methyl formate 0.1%, methyl nitrite 5%, CO 15%, NO 8%, and the rest is N 2 , CO feed 3 flow rate is 9880Nm 3 / h, purity 99.5%, H 2 500ppm, and methanol feed 4 flow rate is 15500kg / h, purity 99.9%.

[0064] The reaction temperature of the oxidative esterification reactor is 30° C., and the reaction pressure is 0.1 MPag.

[0065] The theoretical plate number of the weight-removing tower is 30, the operating pressure at the top of the tower is 150kPaG, and the temperature at the to...

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Abstract

The invention relates to a method for separating dimethyl carbonate. The method adopts an oxidative esterification reactor, ahigh low boiling fraction removaltower, a linaethol recovery tower, a low boiling fraction removaltower, an alkaline bath, a methyl alcohol recovery tower and a dimethyl carbonate separating tower to separate methanol and dimethyl carbonate. By adopting the method, the process energy consumption is reduced while the quality of products is ensured, and the method can be used for industrial production of dimethyl carbonate separation in the dimethyl oxalate synthesis process.

Description

technical field [0001] The invention relates to a method for separating dimethyl carbonate, especially for the process of synthesizing dimethyl oxalate using coal-based synthesis gas, natural gas, coke oven gas, blast furnace gas, calcium carbide furnace tail gas, etc. as raw materials. Qualified dimethyl carbonate product is obtained, and methanol is recycled by alkali washing at the same time. Background technique [0002] In the process of synthesizing dimethyl oxalate (DMO), methyl nitrite and CO undergo a gas-phase catalytic coupling reaction on the catalyst to generate DMO, and at the same time, there is a side reaction to generate dimethyl carbonate (DMC). The reaction equation is as follows: [0003] 2CH 3 ONO+2CO→(COOCH 3 ) 2 +2NO [0004] The main side effects are: [0005] 2CH 3 ONO+2CO→CO(OCH 3 ) 2 +2NO [0006] The by-product methyl formate (MF) is also formed in the presence of hydrogen. The reaction equation is as follows: [0007] [0008] Both...

Claims

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Application Information

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IPC IPC(8): C07C69/96C07C68/00C07C68/08C07C203/00C07C201/04C07C29/80C07C31/04
CPCC07C29/80C07C68/00C07C68/08C07C201/04C07C69/96C07C203/00C07C31/04
Inventor 胡松杨卫胜
Owner CHINA PETROLEUM & CHEM CORP
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