KR100220576B1 - Low pressure ethanol psa drying device using carbon dioxide - Google Patents

Abstract

이상)을 얻기 위해 증류탑에서 얻어지는 에탄올과 공비혼합물(92-95

)로부터 선택적 흡착방법에 의해 물을 추가적으로 제거시키기 위하여 제올라이트(Zeolite)흡착제를 이용하여 압력스윙 흡착방식으로 에탄올을 탈수시키는 공정에서, 저압에서 물의 탈착을 돕기 위해 이미 건조된 에탄올의 일부를 다시 흡착층(Adsorption Bed)으로 흘러 보내서 퍼지(Purge)시키는데, 이러한 퍼지용 에탄올을 이산화탄소로 대체하며 수율의 감소를 방지하고 공정의 경제성을 향상시킨 이산화탄소를 이용한 저압식 에탄올 압력스윙흡착 탈수장치에 관한 것으로, 원료기체흐름(1)에 이산화탄소 재순환흐름(2)을 더하여 흡착층(5)에서 흡착시키고 건조된 이산화탄소를 재생과정의 흡착층(10)에 보내 퍼지를 돕도록 하며, 퍼지된 기체흐름에서 묽은 에탄올 용액을 응축제거한 후 얻어진 이산화탄소를 진공펌프(14)와 송풍기(16)를 거쳐 압축시킨 후 다시 원료기체와 혼합시키는 것이다.The present invention is a high purity alcohol (99.5) used as a fuel alcohol

Ethanol and azeotrope (92-95)

In the process of dehydrating ethanol by pressure swing adsorption using a zeolite adsorbent to further remove water by the selective adsorption method, a portion of the already dried ethanol is re-adsorbed to assist the desorption of water at low pressure. The present invention relates to a low pressure ethanol pressure swing adsorption dehydration device using carbon dioxide, which replaces the purge ethanol with carbon dioxide and prevents a decrease in yield and improves the economics of the process. The carbon dioxide recycle stream (2) is added to the gas stream (1) to adsorb in the adsorption layer (5) and to send the dried carbon dioxide to the adsorption layer (10) during the regeneration process to assist purge, and dilute ethanol solution in the purged gas stream. After condensation removal, the obtained carbon dioxide is compressed through a vacuum pump (14) and a blower (16), and then again. It is to mix with the gas exit.

Description

Low Pressure Ethanol Pressure Swing Adsorption Dewatering System Using Carbon Dioxide

이상)을 얻기 위해, 증류탑에서 얻어지는 에탄올과 공비혼합물(92-95

)로부터 선택적 흡착방법에 의해 물을 추가적으로 제거시키기 위하여 제올라이트(Zeolite)흡착제를 이용하여 압력스윙 흡착방식으로 에탄올을 탈수시키는 공정에서, 저압에서 물의 탈착을 돕기 위해 이미 건조된 에탄올의 일부를 다시 흡착층(Adsorption Bed)으로 흘려 보내서 퍼지(Purge)시키는데, 이러한 퍼지용 에탄올을 이산화탄소로 대체하며 수율의 감소를 방지하고 공정의 경제성을 향상시킨 이산화탄소를 이용한 저압식 에탄올 압력스윙 흡착 탈수장치에 관한 것이다.The present invention is a high purity alcohol (99.5) used as a fuel alcohol

To obtain an azeotrope (92-95)

In the process of dehydrating ethanol by pressure swing adsorption using a zeolite adsorbent to further remove water by the selective adsorption method, a portion of the already dried ethanol is re-adsorbed to assist the desorption of water at low pressure. The present invention relates to a low pressure ethanol pressure swing adsorption dehydration apparatus using carbon dioxide which replaces the purge ethanol with carbon dioxide and prevents a decrease in yield and improves the economics of the process.

Conventional US patent (US 4,407,662) ethanol adsorption dehydrator is heated by heating the ethanol solution to make a superheated steam and then dried by passing through the adsorption layer consisting of crystalline 3A zeolite, the adsorption layer used for adsorption is used to desorb and regenerate water again At the time of regeneration of the adsorption layer, the pressure of the adsorption layer is lowered, and further, other components other than water, ie, dried ethanol, are flowed back into the adsorption layer to lower the partial pressure of water in the adsorption layer.

이상에 해당하는 에탄올이 손실되는 것이 종래 공정의 경제성을 저하시키는 요인이 되고 있다.30 in the raw material solution during the adsorption layer regeneration process

The loss of ethanol corresponding to the above is a factor that lowers the economics of the conventional process.

The use of other substitutes instead of dried ethanol vapor as the purge material in the adsorption bed regeneration process will prevent ethanol loss during the purge process, but this has not yet been done in the low pressure ethanol adsorption dehydration process.

농도의 에탄올 용액을 농축시켜 90

정도의 용액을 만드는 것으로서 99.5

의 연료용 알코올을 생산하는데는 적합하지 못한 것으로 판단된다.Carbon dioxide is used as a purge substitute in the ethanol adsorption dehydration process, and there is a US patent (US 4,273,621). However, the process is an adsorption process performed at high pressure of 3 to 7 atm. There are additional problems such as the equipment cost according to the process, the fuel cost for making high-pressure ethanol superheated steam, the equipment cost of the compressor used to compress carbon dioxide back to high pressure, and the operating cost.

Concentrate the ethanol solution at 90

99.5 by making a solution

It is not suitable to produce alcohol for fuel.

나 차지하므로서 흡착층을 지나는 기체의 선속도가 과다하게 높아지고 결과적으로 흡착층의 흡착능(Adsorption Capacity)이 크게 저하되므로 장치의 크기가 커지게 되는 문제점을 안고 있다.In the above patented process, carbon dioxide in the carbon dioxide and ethanol vapor mixture is 80

As a result, the linear velocity of the gas passing through the adsorption layer is excessively increased, and as a result, the adsorption capacity of the adsorption layer is greatly reduced, thereby increasing the size of the device.

Therefore, the present invention was created for the purpose of improving the above-mentioned conventional problems, while maintaining the low pressure during the adsorption, avoiding the problems caused by high pressure operation, while replacing the ethanol vapor used in the purge process of the adsorption phase with carbon dioxide to reduce the loss. The membrane is to provide a production method.

As a means for providing the above apparatus, a small amount of carbon dioxide is injected into a conventional low pressure adsorption dehydration process to purge the adsorption layer, and the used carbon dioxide is separated from the water and ethanol solution, dried and circulated for regeneration of the adsorption layer. It is to provide a process that can be used as an alternative.

1 is a flow chart showing a process apparatus of the present invention.

* Explanation of symbols for main parts of the drawings

1: material flow 2: carbon dioxide recycle flow

3,6,9,11,17,18,19,20: opening and closing side

5,10: adsorption layer 7,12: cooler

8, 13, 15: gas-liquid separator 14: vacuum pump

16: blower

Hereinafter, the configuration and operation of the present invention will be described in detail with reference to the accompanying drawings.

로 정제된 에탄올을 과열기(Superheater)에서 가열하여 얻어지는 것으로서 1.2-2기압의 압력과 100-140

의 온도를 가지고 있으며 재생분리된 이산화탄소 흐름(2)과 합쳐져서 개폐변(3)과 인입관(4)을 통과하여 흡착층(5)으로 유입되며 흡착층(5)에서 흐름중의 물이 흡착됨에 따라 건조된 에탄올증기와 이산화탄소는 개폐변(6)과 냉각기(7)에서 냉각된 후 기액분리기(8)에서 에탄올 용액과 이산화탄소 기체로 분리되며 이산화탄소 기체는 개폐변(9)을 통과하여 흡착층(10)의 퍼지과정에 사용되게 된다.In Figure 1, the raw ethanol gas stream (1) is produced in the ethanol fermentation process and is 92-95 in the distillation process.

Obtained by heating the purified ethanol in a superheater, and the pressure of 1.2-2 atm and 100-140

It is combined with the regenerated separated carbon dioxide stream (2) and passes through the opening / closing valve (3) and the inlet pipe (4) to enter the adsorption layer (5). The ethanol vapor and carbon dioxide dried according to the present invention are cooled in the open / close valve 6 and the cooler 7, and then separated into an ethanol solution and a carbon dioxide gas in the gas-liquid separator 8, and the carbon dioxide gas passes through the open / close valve 9 and the adsorption layer 10) to be used in the purge process.

During the purge process, a low pressure of 0.1 to 0.4 atm is maintained to assist the desorption of water from the adsorption layer 10. The carbon dioxide, water, and ethanol from the adsorption layer 10 pass through the opening and closing side 11 to cool the cooler 12 After cooling in the) into the gas-liquid separator (13) is separated into a gas ethanol solution and carbon dioxide as the main component.

The gas flow enters the gas-liquid separator 15 through a vacuum pump 14 for lowering the in-process pressure to a low pressure, removes some water and ethanol contained in the gas stream as a solution, and passes through a blower 16 at 2 atmospheres. You get a degree of pressure.

In this case, carbon dioxide may be additionally supplied if necessary, and carbon dioxide may be used in the ethanol fermentation process.

The gas flow from the blower 16 is mainly composed of carbon dioxide, which is dried together with the raw ethanol gas to be adsorbed and dried, and then used as a purge material for desorption and regeneration of the adsorption layer.

And the opening and closing valves 17, 18, 19, and 20 that are not used have the role that the opening and closing valves 3, 6, 9, and 11 previously performed when the circulation cycle of the adsorption layer was changed. Will be reversed.

In the present invention, by reducing the ethanol vapor used as the purge material of the adsorption layer by the cyclic use of carbon dioxide to improve the process yield, as well as operating at low pressure as in conventional commercial processes, the effect of reducing the process ratio It is.

Claims (5)

92-95 from distillation column

Dehydrate ethanol 99.5

In the process for producing the above alcohol for fuel, ethanol vapor at low pressure passing through the adsorption layer consisting of crystalline 3A zeolite and dried, carbon dioxide, characterized in that to improve the ethanol recovery by using carbon dioxide as the adsorption material for purge Low pressure ethanol pressure swing adsorption dehydration device using. The low pressure ethanol pressure swing adsorption dewatering device using carbon dioxide according to claim 1, wherein the low pressure is operated while swinging a pressure of 0.1-2 atmospheres. The low pressure ethanol pressure using carbon dioxide according to claim 1, wherein instead of purging a portion of the ethanol that has passed through the adsorption layer, the gaseous phase separator separates the ethanol and sends gaseous carbon dioxide to the adsorption layer for purging. Swing adsorption dehydrator. The method of claim 3, wherein a vacuum pump is installed to obtain low pressure, and the recovered carbon dioxide is pushed to 1-2 atm using a blower, and if necessary, the carbon dioxide obtained in the ethanol fermentation process is supplemented to obtain a desired pressure. Low pressure ethanol pressure swing adsorption dehydration device using carbon dioxide. Carbon dioxide obtained by cooling and condensing the ethanol and water in the desorbed stream to be returned to the distillation column for treatment, and the carbon dioxide obtained in the gaseous phase is once again recovered through a condensation step and dried and mixed with raw ethanol gas to enter the adsorption layer. Low pressure ethanol pressure swing adsorption dehydration device using.

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