The gas exiting the safety valve is dehydrogenated of H2S.
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Question: Current situation of the plant: There is a buffer tank at the outlet of the compressor, and the gas entering this tank contains H2S. Therefore, the outlet of the safety valve located on top of the tank cannot be connected directly to the flare system. Since there are no sulfur recovery units or acidic gas pipelines in the vicinity of the plant, it is necessary to remove the H2S component from the gas before connecting the outlet of the safety valve to the flare system. However, the specificity of this issue is that the probability of the safety valve activating is low; therefore, installing a separate H2S treatment system would certainly be excessive. My idea is to use an alkaline solution (such as MDEA) as a liquid seal at the outlet of the safety valve; when the safety valve activates, the gas first passes through this alkaline solution before entering the flare system. I wonder if this will work? Has anyone with more experience dealt with similar problems before? Thank you.
Judging from the hydrogen sulfide concentration, this liquid seal certainly won’t be effective for absorption; the gas will definitely break through the liquid seal. Generally, there is at least one small spray tower. Generally, it is possible to direct the gas from the outlet of the safety valve into the air path or equipment at the inlet side; this is also a common approach.
A single torch system might be a safer option, but given the owner’s conditions, the investment required might be too high. @ylb913 @ZhizheMing @RedLee_ZZHI
There are various ways to handle this, such as installing acid gas flares, using scrubber towers for spray washing, or employing RTO combustion. Overall, setting up an acidic gas flare separately is a safe and economical approach.
What is the leakage rate? A torch system isn’t that simple – do you have a place to build the torch? Still, look at the leakage rate, check your PID, and check your pressure – is it only the PSV? There should be BDV as well, right?
Hello, the maximum leakage rate when the valve is closed accidentally is 76,800 kg/h. I’m asking the owner to find the relevant PID; I’ve requested it from them, but it hasn’t been provided yet. Thank you
It is indeed rather cumbersome to set up an acidic gas flare specifically for this safety valve, as the investment required is too high.
Hello: “Generally, it is possible to direct the gas coming from the outlet of the safety valve into the air circuit or equipment at the inlet side; this is a common practice.” Are there any relevant standards or guidelines supporting this approach? Thank you.
Installing acid gas torches and spray scrubbers in the alkali scrubber towers indeed requires significant investment, and there are no incinerators in the vicinity.