Issues in the treatment of hydrogen sulfide waste gas
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The H2S gas generated by our current wastewater neutralization tanks has a concentration of about 240 ppm, along with a small amount of acid mist. We plan to use caustic soda to absorb this gas; we’re not sure whether this will achieve the required purification level What about dealing with the sodium sulfide and sodium hydrosulfide produced by absorption? I hope the experts here can offer some guidance
You need to decide how much H2S you want to control – below 50 is fine; alkaline absorption works well for this, but it’s more difficult to handle in the case of solutions. Additionally, the operation of the device requires careful consideration, as crystallization and blockages can always occur
Thank you for your reply. The emission standard for H2S is 0.33 kg/h; with a gas flow rate of 8900 Nm3/h, this means it needs to be kept below 25 ppm. Regarding the issue of crystallization, are there any good methods available to solve it at present? I saw other online solutions for converting H2S into sodium hydrosulfide, which mentioned the use of catalysts. I would like to ask what kind of catalyst is needed? Are there any catalysts that can solve the crystallization problem?
It’s possible to carry out the process directly through alkaline absorption without the use of a catalyst, but strict monitoring of the process is necessary. The crystallization of sodium hydrosulfide is not easy to control, and the working environment can also be quite challenging
Hydrogen sulfide is easy to handle; it’s just that the by-products formed are difficult to deal with
It is feasible to use alkalis to absorb hydrogen sulfide; I’m not clear what you mean by \"meeting the standards.\" Sodium sulfide and sodium hydrosulfide are indeed difficult to handle, so they are basically given away to other manufacturers for processing.
Your air volume is quite high; use the smaller model for glue bonding and desulfurization instead
What are the temperature and pressure of this gas? Contains oil or not
At normal pressure and a temperature of 50~58°C, oil-free. Contains only a small amount of sulfuric acid mist
With sulfuric acid mist, whether sodium sulfide and sodium hydrosulfide can be formed depends on the ratio of sulfuric acid to hydrogen sulfide; using a base for absorption will result in sodium sulfate
There is another question: should dilute alkali or concentrated alkali be used for absorption? Why? What are their respective advantages and disadvantages?