Abstract:
Objective During the start-up and shutdown processes of the natural gas purification unit, the tail gas is directly discharged without the SCOT tail gas treatment unit, and it has the characteristics of long time, high emission, complex composition and large fluctuation. During this period, a large amount of SO2 may accumulate. Therefore, it is necessary to take measures to achieve SO2 emission reductions during the start-up and shutdown processes.
Method Aiming at SO2 and H2S in tail gas, a desulfurization process by tail gas absorption-adsorption coupling method was proposed. And the research focused on the absorption of SO2 using an alkaline solution and the adsorption of H2S onto a renewable adsorbent.
Results The alkaline solution absorption process could ensure that SO2 was almost completely absorbed, and basically did not absorb H2S and CO2, which could avoid the excessive consumption of alkaline solution. 13X molecular sieve had a good adsorption effect on H2S and regenerative effect, which could adsorb circularly. The regenerated H2S can also be recycled once the facility is restarted and operating stably.
Conclusions The absorption of SO2 coupled with adsorption of H2S in tail gas can ensure that the SO2 discharge of the natural gas purification plant is greatly reduced during the start-up and shutdown processes, and the process is simple with a high operational flexibility.
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