Full temperature range-pressure swing adsorption (FTrPSA) separation method for reaction cycle gas in direct oxidation of ethylene to ethylene oxide

A technology of ethylene oxide and separation method, applied in the field of FTrPSA separation, can solve the problems of impurity accumulation, waste, unstable cycle ratio, etc., and achieve the effects of low energy consumption and high elasticity

Active Publication Date: 2019-09-17
ZHEJIANG TIANCAIYUNJI TECH CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In view of the above-mentioned problems in the EO production process and the reaction cycle gas circulation process of the device, there are many problems including accumulation of impurities, unstable cycle ratio, low efficiency of the decarbonization tower, and waste of stable gas caused by ethylene and methane. The present invention uses a full temperature range Pressure swing adsorption (FTrPSA) gas separation method, that is, full temperature range pressure swing adsorption (Full Temperature Range-Pressure Swing Adsorption, referred to as: FTrPSA) is a separation technology based on pressure swing adsorption, making full use of the raw material gas The temperature and pressure of the reaction mixture produced by the ethylene oxide (EO) device itself, the temperature range of each component in the raw gas at 10~120°C, and the adsorption separation coefficient and physical The difference in chemical properties, through the coupling of various separation methods to adjust the adsorption or regeneration of the pressure swing adsorption cycle process, so as to realize the easy matching and balanced cycle operation of adsorption and desorption in the pressure swing adsorption process to separate, purify and purify the EO reaction mixed gas method, and then can flexibly adjust the ratio of the reaction cycle gas, while preventing the accumulation of impurities in the cycle process, improve the decarbonization efficiency, and reduce the waste of ethylene and methane-induced stabilizing gas

Method used

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  • Full temperature range-pressure swing adsorption (FTrPSA) separation method for reaction cycle gas in direct oxidation of ethylene to ethylene oxide
  • Full temperature range-pressure swing adsorption (FTrPSA) separation method for reaction cycle gas in direct oxidation of ethylene to ethylene oxide
  • Full temperature range-pressure swing adsorption (FTrPSA) separation method for reaction cycle gas in direct oxidation of ethylene to ethylene oxide

Examples

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Effect test

Embodiment 1

[0032] A kind of FTrPSA separation method of reaction circulation gas in ethylene method system ethylene oxide, comprises the steps:

[0033] (1) Medium-temperature PSA enrichment 1 (PSA1), the non-condensable gas from the top of the ethylene oxide (EO) scrubber is used as the raw material gas,

[0034] Its components are ethylene 20.2% (volume ratio, the same below), oxygen 6.0%, methane 49.4%, argon 10.4%, carbon dioxide 12.0%, and the rest 1.0%, mainly including water, nitrogen, ethylene glycol, carbon monoxide etc., the temperature is 80°C, the pressure is 1.7MPa, the gas flow rate is 10,000 standard cubic meters per hour, and it directly enters the medium temperature 5-tower series pressure swing adsorption concentration system with an operating temperature of 80°C and an operating pressure of 1.7MPa. A variety of adsorbent combinations filled with activated alumina, silica gel, activated carbon, and molecular sieves are used. The control system composed of regulating val...

Embodiment 2

[0038] Based on Example 1, such as figure 2 As shown, in step (1), the non-condensable gas from the top of the ethylene oxide (EO) scrubber is used as the raw material gas, and 60~70% of it can be bypassed by PSA1 as the EO reaction cycle gas and directly enter the cycle The gas compressor is recycled, and 30~40% of it directly enters the PSA1 and PSA2 systems for processing. Correspondingly, the 5-tower operation is automatically switched to the 4-tower operation control system, and the PSA operation mode of the two processes is switched from PSA5-1-2V to PSA4-1-2V meets the requirement of 30~40% operating flexibility of the PSA unit, and can adjust the ratio of the direct reaction cycle gas volume through the PSA1 bypass to the indirect reaction cycle gas volume processed by the PSA1 system to maintain the EO reactor. The effective composition of the working concentration and stable and complete operation.

Embodiment 3

[0040] Based on Example 1, such as image 3 As shown, the non-condensable gas from the top of the ethylene oxide (EO) scrubber described in step (1) is used as the raw material gas, and first enters the temperature swing adsorption (TSA) system composed of three adsorption towers in series for drying and dehydration , among which, one of the three towers is adsorption, one tower is hot blowing, and the other is cold blowing. Each adsorption tower is filled with various adsorbent combinations of activated alumina, silica gel, and molecular sieve. The adsorption temperature is 76~80°C, and the regeneration temperature is 200 ~220°C, the argon-rich non-adsorbed phase gas from the PSA2 system is used as the regeneration carrier gas, and the generated regeneration waste gas is used as the fuel gas and directly enters the fuel gas pipeline network. The inlet and outlet pipes of each adsorption tower in the drying system are connected with heaters.

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Abstract

The invention discloses a full temperature range-pressure swing adsorption (FTrPSA) separation method for reaction cycle gas in direct oxidation of ethylene to ethylene oxide. The FTrPSA separation method comprises the following steps: (1) allowing raw material gas to undergo intermediate temperature pressure swing adsorption (PSA) concentration 1 (PSA1), allowing non-adsorbed phase gas to flow out and undergo intermediate temperature pressure swing adsorption (PSA) concentration 2 (PSA2), and allowing adsorbed phase gas to flow out and enter a decarbonization tower; (2) allowing the non-adsorbed phase gas flowing out from intermediate temperature pressure swing adsorption (PSA) concentration 2 (PSA2) to be directly discharged, and allowing the adsorbed phase gas rich in methane and ethylene to flow out as EO reaction cycle gas and pass through a recycle gas compressor to return to an EO reactor for a reaction; and (3) allowing non-condensable gas flowing out from the top of an absorption tower used for absorbing removed carbon to be used as EO reaction recycle gas to return to the EO reactor for recycling, allowing a carbon-dioxide-rich absorption solution flowing out from the bottom of the absorption tower to enter a desorption tower through a circulation pump, heating a potassium carbonate solution flowing out from the bottom of the desorption tower, then mixing the heated potassium carbonate solution with a part of a potassium carbonate solution newly supplemented at regular time, allowing an obtained mixed potassium carbonate solution to return to the absorption tower for recycling, and allowing carbon-dioxide-rich desorption gas flowing out from the top of the desorption tower to be directly discharged.

Description

technical field [0001] The invention relates to the field of gas separation in petrochemical industry, in particular to a FTrPSA separation method for reaction cycle gas in the direct oxidation of ethylene to ethylene oxide. Background technique [0002] As the main derivatives of ethylene, ethylene oxide (EO) and its downstream ethylene glycol (EG) are widely used in surfactants, synthetic fibers and other fields. However, the production process of EO involves very important stability and safety First, the raw material ethylene, oxygen and product EO required for the reaction are all flammable and explosive chemicals, and the working concentration of these chemicals must be controlled below the explosion limit. Generally, methane or nitrogen is used as a stabilizer (gas) to dilute the concentration of ethylene, oxygen and EO, so that the working concentration of these dangerous chemicals is diluted below their respective explosion limits in air; secondly, ethylene and oxyge...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D53/047B01D53/22B01D53/62B01D53/78
CPCB01D53/047B01D53/229B01D53/62B01D53/78B01D2251/306B01D2251/606B01D2257/11B01D2257/504Y02A50/20Y02C20/40
Inventor 汪兰海陈运唐金财钟娅玲钟雨明蔡跃明
Owner ZHEJIANG TIANCAIYUNJI TECH CO LTD
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