Method and device for separating hydrogen and hydrocarbon in petroleum drying gas by using multi-stage cascade temperature-changing membrane

Abstract

The invention relates to a method for separating hydrogen and hydrocarbon in a petroleum drying gas by using a multi-stage cascade temperature-changing membrane. In the method, after preprocessed, a mixed gas source firstly passes through a hydrogen separating membrane A for primarily separating partial hydrogen; seeped residual gas enters an organic gas separating membrane B for secondarily separating hydrocarbon components; and the seeped residual gas of the membrane B enters a hydrogen separating membrane C for thirdly separating the hydrogen. The invention also provides a device for separating low-concentration hydrogen in the petroleum drying gas by using the cascade membrane. The invention has the advantage that the organic gas separating membrane is arranged between the two hydrogen separating membranes for separating the hydrocarbon gases to ensure that liquid hydrocarbon is separated out during the secondary hydrogen membrane separation. Meanwhile, separating temperatures of the three separating membranes are calculated and the three membranes are configured by using an HYSYS and the hydrocarbon and hydrogen proportion in the mixed gas source, thereby ensuring that the membrane separating property and the membrane configuration are optimal.

Description

Technical field [0001] The present invention involves multi -level tandem temperature -transformed membrane to separate hydrocarbons in petrochemicals and its device. It is not only suitable for the industrialized and efficient separation of hydrocarbons in the dry gas of the refinery, but also applicable to other hybolized hybrids.Or the processing of hydrogen hydrocarbon, which is transformed into hydrogen -based hydrocarbons, is divided into efficient separation.It belongs to the field of gas separation technology. Background technique [0002] With the continuous development of the petrochemical industry, the continuous progress of processing and synthetic technology, the circulating gas, release gas and exhaust gas contained in the oil processing and chemical synthesis industries contain a large amount of hydrocarbon gases.Burning will be a great waste of resources and increasing industrial costs accordingly.A variety of valuable chemical raw materials such as ethylene, acry...

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Problems solved by technology

[0003] Now the commonly used separation methods in industry include cryogenic separation method, shallow cold separation method, oil product absorption method, adsorption method, membrane separation method and other methods; there are also methods combining these three or two methods at home and abroad. Patents (92109983.5, 200710131549.4, 200610135849.5 and 92100812.0, etc.), but they are rarely used in industry and the cost is relatively high

There are also patents (93103019.6, 95117302.2) using two-stage membrane separation and variable temperature two-stage membrane separation, but these patented technologies cannot separate mixed gas sources with relatively large hydrogen and hydrocarbon components, nor can they separate hydrogen content between 30% and 60%. Most of the hydrogen membrane separation devices that have been used in the industry are used to separate the mixed gas source with a hydrogen content of more than 60%; if the mixed gas source with a low hydrogen content and a high hydrocarbon content is separated, there will be liquid Hydrocarbons are precipitated in the second hydrogen membrane separation process

Because of the high hydrocarbon content, during the hydrogen separation process, with the separation and seepage of hydrogen, the partial pressure of the hydrocarbon components will increase, and the gaseous hydrocarbons will become liquid and precipitate in the membrane, which will damage the performance and use of the separation membrane. life

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