Method and system for jointly treating refinery gas by adopting membrane separation and pressure swing adsorption

Abstract

The invention provides a method and a system for jointly treating a refinery gas by adopting membrane separation and pressure swing adsorption. According to the method, multiple refinery gases are sorted as reforming hydrogen, a low-pressure hydrogen-poor gas, a low-pressure hydrogen-rich gas, a high-pressure hydrogen-poor gas and a high-pressure hydrogen-rich gas according to different requirements of a membrane separation device and a pressure swing adsorption device on the composition and pressure of a feed gas; hydrogen is recovered from the reforming hydrogen through the membrane separation device or the pressure swing adsorption device; the low-pressure hydrogen-poor gas and the high-pressure hydrogen-poor gas are purified through the membrane separation device and then hydrogen is recovered through the pressure swing adsorption device; and hydrogen is recovered from the high-pressure hydrogen-rich gas and the low-pressure hydrogen-rich gas through the pressure swing adsorption device. The invention also provides a system for the method. The method and system which are provided by the invention have the characteristics of high hydrogen purity and high recovery rate, are suitable for the yield increase of an old device and high in operating flexibility and can achieve the recovered hydrogen purity more than 99vol / % and the recovery rate more than 95%.

Description

technical field [0001] The invention belongs to the field of recovery and treatment of refinery gas, and in particular relates to a method and system for jointly treating refinery gas by using membrane separation and pressure swing adsorption. Background technique [0002] Refinery demand for hydrogen has increased significantly as fuel cleanliness requirements have become increasingly stringent. Oil refineries use hydrogenation technology to further process and treat oil products, and the process consumes a lot of hydrogen. However, due to equipment and process limitations, many hydrogen-facing devices discharge a large amount of hydrogen-rich refinery gas into the gas pipeline network. This part of hydrogen has not been recycled, which not only increases the cost of hydrogen production, but also reduces the calorific value of the gas pipeline network. The problem affected the normal production of the refinery. [0003] Efficient and high-quality recovery of hydrogen from...

AI Technical Summary

Problems solved by technology

The main processes of hydrogen recovery are membrane separation and pressure swing adsorption, both of which have their own characteristics: the membrane separation method has the characteristics of modularization, simple installation, no moving parts, simple maintenance, high recovery rate and large operating flexibility, but the raw material hydrogen concentration When the purity of the hydrogen product is low, the purity of the hydrogen product cannot meet the requirements of the hydrogen network; the pressure swing adsorption method is flexible in operation and can obtain high-purity hydrogen, but its control steps are complicated and the expansion of the device is difficult

[0004] At present, the main hydrogen purification and recovery process in the refinery adopts the pressure swing adsorption method. Due to the increase in the demand for hydrogen, the device operates at full capacity for a long time, and the adsorbent is easily saturated. After repeated regenerations, the ideal adsorption effect cannot be achieved, often causing hydrogen Problems such as low purity and high hydrogen concentration in desorbed gas

In actual production, the processing capacity of the pressure swing adsorption device not only cannot meet the demand, but also often causes the output to decrease due to the adsorption agent.

[0005] Therefore, it is necessary to find new technical solutions for the shortage of hydrogen sources caused by insufficient hydrogen treatment capacity and low recovery rate commonly found in PSA units in refineries.

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