The basic principle of the reaction is to touch the marsh gas containing H2S and the soda water solution containing the chemoautotrophic microorganism. After the H2S is absorbed by the alkaline solvent, the element sulfur or sulfate is generated by the microbial catalysis. The main reactions in the bioreactor are as follows:
Now, technology is one of the world's more sophisticated desulfurization technologies, which has the following advantages:
(1) Safety: all biological desulfurization systems are closed and operated, and the H2S in the biogas is completely absorbed. There is no free H2S in the downflow of the absorber, no poisoning and casualties, and no environmental pollution.
(2) Saving: the skill requires less investment, and the number of primary equipment and instruments is small. The operation cost is low, the production needs fewer operators, and the labor cost is reduced; without chemical catalyst, the biocatalyst will not be inactivated, it will regenerate automatically without replacement, and the operation needs less chemicals, saving the production cost; the operation cost and protection cost of this skill are very low.
(3) High efficiency: use this technology to ensure that the content of H2S in the desulfurized natural gas is less than 4ppmv; and the operation flexibility is large. It is used to H2S concentration scale of 50ppmv-100vol.% and pressure scale of 1-100barg. It has high flexibility and can be used to the peak load of H2S.
The skill flow of the skill is simple, the control system and monitoring system are few, there is no disordered control circuit, and the operation and protection are simple and convenient. It is suitable for small gas fields with high concentration of H2S, which is more economical and has very good benefits. Moreover, the equipment using this skill has stable functions, reliable skills and good economic benefits.
3.2 skill principle of iron salt absorption biological desulfurization
The basic principle of biological desulfurization by iron salt absorption is that H2S is oxidized by Fe3 + to elemental sulfur during absorption, and then Fe2 + is transformed into Fe3 + by the metabolism of Thiobacillus ferrooxidans under acid conditions (pH = 1.2-1.8), which is recycled to the absorption period for repeated use, and the relevant repercussions are as follows:
With high oxidation recovery potential, H2S can be converted into elemental sulfur, but elemental sulfur can not be further oxidized into sulfate. The elemental sulfur is recovered after separation, and then Fe2 + is metabolized to Fe3 + by Thiobacillus ferrooxidans and recycled. Therefore, most researchers think that this method is more suitable for the process of biogas desulfurization because of its low energy consumption, less investment and less waste discharge.