Method for preparing ethene by ethanol dehydration

An ethanol dehydration and ethylene technology, which is used in the production of hydrocarbons from oxygen-containing organic compounds, chemical recovery, organic chemistry, etc., can solve the problems of high energy consumption of the device, large ethanol loss, and high COD value of wastewater, and achieve high heat utilization. The effect of reducing energy and saving investment

Active Publication Date: 2012-03-14
CHINA PETROLEUM & CHEM CORP +1
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Problems solved by technology

[0006] The technical problem to be solved by the present invention is that in the production process of ethanol dehydration to ethylene, the loss of ethanol is large, the COD value of wastewater is high, and the energy consumption of the device is high. A new method for ethanol dehydration to ethylene is provided

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Examples

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Embodiment 1

[0026] use figure 1 In the process flow shown, the theoretical plate number of the stripper is 20, and the operating pressure is 0.6MPa(G). Raw material ethanol 2350kg / h, wherein ethanol 1997.5kg / h, water 352.5kg / h, ethanol content 85% (wt%). Raw ethanol is fed from the top of the stripper. The reaction temperature is 350°C, the reaction pressure is 0.04MPaG, and the liquid volume space velocity of ethanol is 0.8 hours -1 , dehydrated to ethylene under the action of alumina catalyst. The reaction product is firstly washed with water, then washed with alkali, and then enters the ethylene rectification tower. The ethylene rectification tower is a plate tower; the operating gauge pressure is 1.0MpaG. The ethanol 66.08kg / h and water 1932kg / h in the mixed kettle liquid of the water washing tower and the ethylene rectifying tower enter the stripping tower at the 8th theoretical plate from the top of the stripping tower to recover ethanol. The steam discharged from the top of th...

Embodiment 2

[0028] According to the conditions and steps of Example 1, keep the operating conditions of the reaction system, water washing, and alkali washing unchanged, the pressure at the top of the ethylene rectification tower is 1.78MPaG, the temperature at the top of the tower is -31°C, and the pressure at the bottom of the tower is 1.81MPaG. The temperature was 1°C, and the reflux temperature was -33°C. Ethanol 8.1kg / h and ethylene 1290kg / h in the feed. The feed plate is at the 35th theoretical plate from the top of the column. The condensate at the top of the tower is partly refluxed into the tower with a reflux ratio of 2.0:1, and 1250 kg / h of ethylene product is partially recovered with a purity of 96% (wt%). 7.9kg / h of ethanol in the mixed solution discharged from the ethylene rectification tower tank is sent to the gas stripping tower as raw material. The stripping tower is a packed tower with a working gauge pressure of 1.0MpaG. The ethanol content in the water discharged f...

Embodiment 3

[0030]According to the conditions and steps of Example 1, keep the operating conditions of the reaction system, water washing, and alkali washing unchanged, the pressure at the top of the ethylene rectification tower is 1.78MPaG, the temperature at the top of the tower is -31°C, and the pressure at the bottom of the tower is 1.81MPaG. The temperature was 1°C, and the reflux temperature was -33°C. Ethanol 8.1kg / h and ethylene 1290kg / h in the feed. The feed plate is at the 35th theoretical plate from the top of the column. The condensate at the top of the tower is partly refluxed into the tower with a reflux ratio of 2.0:1, and 1250 kg / h of ethylene product is partially recovered with a purity of 96% (wt%). 7.9kg / h of ethanol in the mixed solution 15 discharged from the ethylene rectification tower tank is sent to the gas stripping tower as raw material. The stripping tower is a packed tower with a working gauge pressure of 1.0MpaG. The ethanol content in the water discharged...

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Abstract

The invention relates to a method for preparing ethene by ethanol dehydration and mainly solves problems of large ethanol loss, high waste water COD value and high energy consumption apparatus in a production process flow of preparing ethene by ethanol dehydration of a prior art. According to the invention, fresh ethanol and recovered ethanol enter a gas stripping column to realize vaporization separation in the gas stripping column; kettle liquid in a column kettle of the gas stripping column is discharged out of a system continuously; ethanol steam is obtained at top of the gas stripping column and enters into the reaction system; dehydrated reaction products enter a washing and alkali washing system to remove impurities of ethanol, acetaldehyde and carbon dioxide, etc.; crude ethene obtained after the washing and alkali washing enters into an ethene rectifying tower; and ethene product is obtained at the top of the tower. The above technical scheme well solves the problems and can be applied to industrial production for preparing ethene by ethanol dehydration.

Description

technical field [0001] The invention relates to a method for the process of producing ethylene by ethanol dehydration. Background technique [0002] Ethylene is a very important petrochemical raw material, and its bulk downstream products mainly include polyethylene, ethylene oxide, ethylene glycol, polyvinyl chloride, styrene, vinyl acetate, etc. [0003] The existing production process of catalytic dehydration of ethanol to ethylene (Gu Zhihua, Current status and prospect of ethanol to ethylene technology [J]. Progress in Chemistry, 2006, 25(8): 847-851) The production process is: the raw material ethanol passes through the preheater 1. After the vaporizer is heated, it is all vaporized and sent to the ethanol dehydration reaction system for reaction. The reaction product (including the reaction product ethylene, water, unreacted ethanol, etc.) from the dehydration reaction system is sent to water washing, water alkali washing, etc. to remove impurities, and after After b...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C11/04C07C1/24
CPCY02P20/584
Inventor 刘军沈伟朱瑛杨卫胜杨为民
Owner CHINA PETROLEUM & CHEM CORP
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