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Method for preparing dimethyl ether by dehydration of methanol

A technology of methanol dehydration and dimethyl ether, applied in the chemical industry, can solve the problems of high energy consumption and large heat energy consumption, and achieve the effects of reducing energy loss, improving conversion rate and excellent technical effect

Active Publication Date: 2014-09-24
黄志忠
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Because the recovered methanol is evaporated from the top of the methanol pressurized rectification tower and then condensed, and requires a certain reflux ratio, which consumes a lot of heat energy; and the recovered methanol is in the liquid phase, and it needs to be heated when it is returned as a raw material Vaporization also consumes a lot of heat energy
Therefore, this method consumes a lot of energy

Method used

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  • Method for preparing dimethyl ether by dehydration of methanol

Examples

Experimental program
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Effect test

Embodiment 1

[0023] Reaction feed is the methyl alcohol of 85 (wt)%, and reaction temperature is 200 ℃, and reaction pressure is 0.5MPa, and methanol liquid volume space velocity is 1.8 hours -1 , the dehydration catalyst is: A1, the dehydration reaction product enters the middle and lower part of the dimethyl ether rectification tower to realize the separation of dimethyl ether and methanol, and the still liquid containing methanol, water, etc. The aerosol-grade dimethyl ether product was obtained from one tray. The dimethyl ether rectification tower is a plate tower with a total of 92 theoretical trays, of which the rectification section has 68 trays, the top pressure is 0.70MPa, the top temperature is 25°C, and the reflux ratio is 1.8. The washing tower is a packed tower with a total of 25 theoretical plates, the pressure at the top of the tower is 0.15MPa, and the temperature at the top of the tower is 20°C. The stripping tower is a packed tower with a total of 10 theoretical plates, ...

Embodiment 2

[0026] The reaction feed is 85 (wt)% methanol, the reaction temperature is 200°C, the reaction pressure is 0.5MPa, and the methanol liquid volume space velocity is 1.8 hours -1 , dehydration catalyst A2, the dehydration reaction product enters the middle and lower part of the dimethyl ether rectification tower to realize the separation of dimethyl ether and methanol, and the still liquid containing methanol, water, etc. is obtained in the bottom of the tower, and the third tower from the top of the tower Plates were obtained as aerosol grade dimethyl ether product. The dimethyl ether rectification tower is a plate tower with a total of 92 theoretical trays, of which the rectification section has 68 trays, the top pressure is 0.70MPa, the top temperature is 25°C, and the reflux ratio is 1.8. The washing tower is a packed tower with a total of 25 theoretical plates, the pressure at the top of the tower is 0.15MPa, and the temperature at the top of the tower is 20°C. The strippi...

Embodiment 3

[0029] The reaction feed is 85 (wt)% methanol, the reaction temperature is 200°C, the reaction pressure is 0.5MPa, and the methanol liquid volume space velocity is 1.8 hours -1 , dehydration catalyst A3, the dehydration reaction product enters the middle and lower part of the dimethyl ether rectification tower to realize the separation of dimethyl ether and methanol, and the still liquid containing methanol, water, etc. is obtained in the bottom of the tower, and the third tower from the top of the tower Plates were obtained as aerosol grade dimethyl ether product. The dimethyl ether rectification tower is a plate tower with a total of 92 theoretical trays, of which the rectification section has 68 trays, the top pressure is 0.70MPa, the top temperature is 25°C, and the reflux ratio is 1.8. The washing tower is a packed tower with 25 theoretical plates in total, the pressure at the top of the tower is 0.15MPa, and the temperature at the top of the tower is 20°C. The stripping...

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Abstract

The invention relates to a method for preparing dimethyl ether by dehydration of methanol, the method comprises the following steps: a raw material methanol and a dehydrated reaction product flowed from the bottom of a methanol dehydration reactor enable heat exchange in a methanol preheater and then introduced in a flash evaporator, liquid phase through flash evaporation is introduced in a methanol vaporization tower for vaporizing, the vaporized methanol is mixed with flash steam and then introduced in the methanol dehydration reactor for reacting, the dimethyl ether and methanol-containing water and little noncondensable gas mixed dehydrated reaction product can be obtained, the dehydrated reaction product is discharged from the bottom of the methanol dehydration reactor, and enables heat exchange with the raw material methanol in the methanol preheater, a mixture is introduced in a dimethyl ether rectifying tower, and is laterally recovered from the upper part of the rectifying tower. By using the method of the invention, system heat can be fully recovered and used, energy consumption is reduced, and conversion rate of methanol and recovery rate of dimethyl ether can be simultaneously increased.

Description

technical field [0001] The invention relates to the field of chemical industry, more specifically, the invention relates to a method for preparing dimethyl ether by dehydrating methanol as a raw material. Background technique [0002] As an important chemical raw material, dimethyl ether (DME) has a wide range of uses, such as propellants for aerosols, refrigerants, fuels and methylating reagents. DME with a purity greater than 99.99% can be used as an anesthetic, and DME with a purity greater than 90% can be used as city gas, liquefied petroleum gas and automobile fuel. Due to the damage caused by chlorofluorocarbons to the atmospheric ozone layer, its use is being gradually restricted worldwide in recent years. The dimethyl ether substitute with a purity of 99.99% is known as the first after compressed gas, CFCS, propane and butane. Four generations of propellants have been widely used in the production of various aerosols. In addition, DME can be used as a raw material ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C43/04C07C41/09
CPCC07C41/09C07C43/04
Inventor 黄清粘
Owner 黄志忠