For processes that generate H2S and NH3 waste gases simultaneously, what is the best purification method?

Traditional treatment processes generally involve absorption using water/weak alkaline solutions. This post was last edited by johncom on 2009-4-18 11:17]

I don’t know what the ratio between the two is; you can calculate their molar ratio of emissions to see if a complete chemical reaction can occur between them, so that they can be combined with water to produce ammonium sulfide or ammonium hydrosulfide.

H2S can be absorbed by dilute alkaline solutions, while NH3 can be absorbed to form ammonia water!

After reacting to form ammonium sulfide or ammonium hydrosulfide, the reaction products do not seem to be stable either; they decompose easily when heated. If these two substances are present, membrane filtration could be considered as an option, given that there is a difference in their molecular weights. For other cases, extraction or absorption processes might be suitable alternatives

The technology used is related to the amount of exhaust gas, the temperature of the exhaust gas, the concentration of ammonia in the exhaust gas, the concentration of hydrogen sulfide, as well as their molar ratio. Unless the aqueous ammonium sulfide solution is a useful substance, using water alone for absorption has little practical value. So which is absorbed using acidic and alkaline aqueous solutions? I guess that’s what is done at the moment. Due to the high solubility of ammonia, it should first be absorbed using an aqueous solution of sulfuric acid or hydrochloric acid, and then hydrogen sulfide should be absorbed using an aqueous solution of sodium hydroxide. The problem is that if the concentrations of hydrogen sulfide and ammonia in the original exhaust gases are very low, yet environmental regulations impose strict requirements on the emission levels of these substances. Therefore, the absorption liquid has to be circulated to ensure the proper operation of the absorption process. Of course, this requires considerable energy consumption. My suggestion is to use a hollow fiber membrane absorber; this approach allows for a very low circulation rate of the absorbent solution while maintaining high absorption efficiency. Furthermore, for conventional absorption, only two towers can be used; hydrogen sulfide must be absorbed first, and then ammonia is absorbed using the second tower. With a membrane absorber, the exhaust gas can pass through a hydrogen sulfide absorber, then an ammonia absorber, then another hydrogen sulfide absorber, then another ammonia absorber, and so on. We produce large-scale industrial membrane absorbers. If you are interested, please contact: yjqin1@yahoo.com or yqin@chembrane.com

Hydrogen sulfide can be absorbed using iron salts or treated through oxidation with oxidizing agents, while ammonia can be absorbed using concentrated acids. If the concentrations of both are not high, biochemical methods can also be used for treatment.

First-stage membrane absorption, second-stage packing absorption.

Biological filtration can be used as long as the hydrogen sulfide concentration is below 3000 ppm, with a very high removal rate of over 95%. If the ammonia concentration is high, a scrubber can be installed to wash it with acid water produced through biological filtration.

It depends on the emission requirements; if those requirements are not high and there is an adequate supply of water, desulfurization using only water can achieve 70% efficiency, as ammonia is highly soluble in water.

Methanol absorption is good, but the price is too high, making it impractical