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Method for separating dimethyl ether and recovering ammonia in co-production process for dimethyl carbonate and dimethyl ether via urea alcoholysis method

A technology for dimethyl carbonate and dimethyl ether, which is applied in the process of co-producing dimethyl carbonate and dimethyl ether by urea alcoholysis method to separate dimethyl ether and recover ammonia, can solve the problem of high total investment in production equipment and large-scale installations. Difficulty in transformation, impact on product economic benefits, etc.

Active Publication Date: 2013-09-11
YASHENTECH CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the methanol oxidative carbonylation process, whether it is a liquid phase method or a gas phase method, has the disadvantage that the catalyst is mainly composed of cuprous chloride or cupric chloride, and the deactivation is serious, which combines with the water generated in the reaction to form The hydrochloric acid is highly corrosive to equipment, resulting in high total investment in production equipment; at the same time, the chlorine ions in the product are difficult to remove, which affects the quality of the product; in addition, the process is carried out under relatively high pressure, the operating conditions are harsh, and the product is economical. Benefits are affected
However, the one-step method still has problems such as low raw material utilization rate, high catalyst requirements, and difficulty in large-scale equipment.
[0017] In addition, in the above-mentioned technology and method for preparing dimethyl carbonate or dimethyl ether, there is the problem of low raw material utilization rate, which makes the production cost higher to a certain extent. Therefore, a new technology or method is needed to increase the Raw material utilization rate, reduce waste, reduce overall production cost

Method used

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  • Method for separating dimethyl ether and recovering ammonia in co-production process for dimethyl carbonate and dimethyl ether via urea alcoholysis method
  • Method for separating dimethyl ether and recovering ammonia in co-production process for dimethyl carbonate and dimethyl ether via urea alcoholysis method
  • Method for separating dimethyl ether and recovering ammonia in co-production process for dimethyl carbonate and dimethyl ether via urea alcoholysis method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0049] In Embodiment 1, the DME separation device 103a adopts the method of producing methylammonium by spraying methanol to separate DME and ammonia and recover ammonia. like figure 2 As shown, the DME separation unit 103 a includes a methanol washing column 201 and a DME-methanol rectifying column 211 .

[0050] The material containing DME and ammonia separated by the separation device 102 in the system 100 enters the methanol washing tower 201 . The DME-containing materials include: ammonia, DME, CO 2 , a small amount of methanol and DMC vapor and other gaseous substances. In one embodiment, the content of ammonia in the material is 39-55wt.%, the content of DME is 16-19wt.%, CO 2 The content of methanol is 17-18wt.%, the content of methanol is 7-22wt.%, and the content of DMC is 2-6wt.%.

[0051] Fresh CO supplemented from outside the system 2 Input methanol washing tower 201 after metering, to keep the CO in the methanol washing tower 201 2 excess.

[0052] Cold m...

Embodiment 2

[0057] In the second embodiment, the DME separation device 103b adopts two rectification methods to separate methanol and recover liquid ammonia / DME. like image 3 As shown, the DME separation unit 103b includes a decarbonization tank 301 , a pre-rectification tower 311 and a main rectification tower 321 .

[0058] The material containing DME and ammonia separated by the separation device 102 in the system 100 enters the decarbonization tank 301 . The DME-containing material includes gaseous substances such as ammonia, DME, CO2, a small amount of methanol and DMC steam. In one embodiment, the content of ammonia in the material is 39-55wt.%, the content of DME is 16-19wt.%, the content of CO2 is 17-18wt.%, the content of methanol is 7-22wt.%, and the content of DMC is 2 ~6wt.%.

[0059] The decarbonization tank 301 has a built-in heat exchanger, which cools the incoming material to about 10°C. CO in the DME-containing material 2 And ammonia form ammonium carbamate crystals i...

Embodiment 3

[0063] In the third embodiment, the DME separation device 103c adopts the method of preparing ammonia water to separate DME and ammonia and recover ammonia. like Figure 4 As shown, the DME separation unit 103c includes a water absorption tower 401 and a flash tank 411 .

[0064] The material containing DME and ammonia separated by the separation device 102 in the system 100 enters the water absorption tower 401 . The DME-containing material includes gaseous substances such as ammonia, DME, CO2, a small amount of methanol and DMC steam. In one embodiment, the content of ammonia in the material is 39-55wt.%, the content of DME is 16-19wt.%, the content of CO2 is 17-18wt.%, the content of methanol is 7-22wt.%, and the content of DMC is 2 ~6wt.%.

[0065] The water absorption tower 401 uses fresh water from outside as absorbent. The material containing DME and ammonia flows upward from the bottom of the water absorption tower 401, and the fresh water from the outside is sent ...

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Abstract

The invention provides a method for separating dimethyl ether and recovering ammonia in a co-production process for dimethyl carbonate and dimethyl ether via a urea alcoholysis method. The method comprises the following steps of: adding methanol and urea in a reaction device, carrying out a reaction on methanol and urea to generate methyl carbamate and a by-product of ammonia, further carrying out a reaction on the generated methyl carbamate and methanol to generate dimethyl carbonate and the by-product of ammonia, and decomposing a part of dimethyl carbonate to generate dimethyl ether; separating out a material containing dimethyl ether and ammonia, and a material containing dimethyl carbonate from the output material of a reaction device; and separating out dimethyl ether from the material containing dimethyl ether and ammonia, converting ammonia to an ammonium carbamate solid, liquid ammonia or ammonia water, and recovering.

Description

【Technical field】 [0001] The invention relates to a method for separating dimethyl ether and recovering ammonia in the process of co-producing dimethyl carbonate and dimethyl ether by urea alcoholysis. 【Background technique】 [0002] Dimethyl Carbonate (Dimethyl Carbonate, DMC for short) is a new type of green chemical that has attracted much attention at home and abroad in recent years, and has been widely used in many fields. Dimethyl carbonate is a colorless, transparent, slightly odorous, slightly sweet liquid at room temperature, hardly soluble in water, but miscible with almost all organic solvents such as alcohols, ethers, and ketones. Because its molecule contains CH 3 -, CH 3 O-, CH 3 O-CO-, -CO- and other functional groups, so it has good reactivity, and can undergo methylation, carbonylation, methyl esterification and transesterification reactions with alcohols, phenols, amines, hydrazines, esters and other compounds. It can replace highly toxic methylating re...

Claims

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Application Information

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IPC IPC(8): C07C69/96C07C68/00C07C43/04C07C41/01C07C41/34C07C41/42C01B21/12C01C1/02
Inventor 王尤崎刘丹
Owner YASHENTECH CORP
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