Hydrogen sulfide is a toxin that can impact the efficiency of biogas. You will have to follow some safe ways to remove this poisonous and corrosive toxin. Whenever you realize the presence of more hydrogen sulfide concentration, you will have to address it immediately. Otherwise, it can cause irreparable damage to the piping and equipment, and the performance will not be up to expectations. Hence, you will have to consider some safe ways for hydrogen sulfide removal from biogas.
How to Know the Presence of More Hydrogen Sulfide in Biogas
The internal engines will perform the best with less than 100 ppm hydrogen sulfide. But the boilers can perform well in 1000 ppm concentration. Whenever there is any disparity in the concentration level, you will have to consider removing it. You will have many safe ways to remove hydrogen sulfide from biogas, and we will cover the most effective ways in the following. You can consider either iron chloride dosing or biological desulphurization.
Iron Chloride Dosing
You will find this method straightforward to follow. Start by feeding the chloride to the digester slurry directly. Once you feed the chloride, it will react with the hydrogen sulfide and form iron particles. The benefit of this method is that it is effective for high hydrogen sulfide levels. But you cannot consider it when you want a low level and stable concentration. Hence, you will have to know the purpose before using this method. When it is high, this process can help with partial removal. But there will be no corrosion, but you will have to combine it with other removal processes to get the desired stability and reduce the concentration. Hydrogen sulfide gas removal.
You will find this process different from the chloride dosing method. It will use microorganisms for hydrogen sulfide removal from biogas. For this method, you will have to use stoichiometric quantities of oxygen to achieve microbiological oxidation, and the oxidation will remove hydrogen sulfide. Know the concentration, add oxygen to the biogas, but make sure that it is two to six percent of the air.
Biological desulphurization is easy to follow and will not cost you more. You can add oxygen to the digester or storage. Once you add the oxygen, it will grow on the surface of the digester and generate required nutrients and micro-aerophilic at the same time. The process will form yellow clusters and impact the sulfide level significantly. The oxygen will reduce the concentration level of the sulfide up to 95%. Also, it can be below 50 ppm, and the result will depend on the temperature and reaction time. But make sure that you are aware of the process before going ahead.
While adding oxygen, you will have to focus on the proper amount. Overdosing can be dangerous. You might know that biogas is explosive within 6 and 12% range of air. If you add more quantity, it might lead to pump failure. While using a steel digester, you might experience corrosion, and you can use rust protection in your digester to avoid such conditions.
Both these methods are helpful, and you can choose depending on availability.
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