Engineers who have run anaerobic reactors know that anaerobic reactions produce biogas, which often contains a certain amount of hydrogen sulfide (H2S). The content of hydrogen sulfide in biogas varies with different industrial wastewater. If the hydrogen sulfide content is too high, it is necessary to remove the hydrogen sulfide in the biogas before the boiler goes out to prevent corrosion of the pipeline and boiler. Today, we will introduce the advanced biogas bio desulfurization technology.
1. Source of Biogas
Biogas usually comes from anaerobic treatment of sewage, feces, straw fermentation, petroleum natural gas, etc. the purified biogas can be used as clean energy, instead of natural gas and coal, for power generation, heating, consumption steam, etc.; the separated hydrogen sulfide gas is converted into solid bio sulfur, which can be used as raw materials for chemical fertilizer, chemical industry and other industries. Biogas can be used to absorb and purify resources, which not only completes energy conservation and emission reduction, but also saves the consumption cost of enterprises.
2. Value of Biogas
1m3沼气≈0.65m3自然气≈0.7kg规范煤≈ 7.5kg 蒸汽≈1.8kwh电，依照工业自然气3.0元/立方米计算，应用1立方沼气可节约1.95元。
1m3 of biogas ≈ 0.65m3 of natural gas ≈ 0.7kg of standard coal ≈ 7.5kg of steam ≈ 1.8kwh of electricity. According to the calculation of 3.0 yuan / m3 of industrial natural gas, 1 cubic meter of biogas can save 1.95 yuan.
2. Difference between biogas desulfurization and flue gas desulfurization
Although biogas desulfurization and flue gas desulfurization are both desulfurization, they are completely different processes. Flue gas desulfurization is to remove SO2 and SO3 from industrial waste gas. As we often say, desulfurization and denitrification refers to the removal of sulfur dioxide. Biogas desulfurization refers to the removal of hydrogen sulfide (H2S) from biogas to reduce the corrosion of subsequent pipelines, extinguished boilers or generators.
3. What is biogas bio desulfurization?
Biogas bio desulfurization (referred to as biogas desulfurization) is a process method to remove the corrosive and toxic hydrogen sulfide gas in biogas by using biological bacteria. This process has the advantages of high automation level, simple process and low operating cost.
3. Process principle
As shown in the figure below, the biogas produced by anaerobic fermentation enters into the washing tower and reacts with the alkaline circulating spray liquid to remove the hydrogen sulfide in the biogas. The rich solution absorbing hydrogen sulfide is returned to the bioreactor, and after biotransformation, hydrogen sulfide is converted into solid elemental sulfur, and the solution is regenerated into an alkaline absorption solution (also known as lean solution) which can be used for washing biogas, so as to complete the recovery and recycling application of absorbent. The separation of sulfur solid is completed through sulfur precipitator.
In this process, the physical and chemical absorption of hydrogen sulfide under weak alkaline condition is separated from the biological regeneration of alkaline solution under the action of air. The biogas containing hydrogen sulfide enters into the washing tower, where it is washed by the alkali solution absorbing hydrogen sulfide. The removal rate of hydrogen sulfide in the treated biogas is as high as 99.5%. After system disposal, biogas can be used for gas generator power generation, boiler fuel or input to local small gas supply network.
Hydrogen sulfide free biogas escapes from the top of the washing tower, and hydrogen sulfide containing solution flows into the bioreactor, where the bacteria oxidize it to elemental sulfur and alkali under the condition of limited oxygen supply. A small amount of discharge liquid (containing sodium salt) and sulfur by-product of the system do not contain sulfide, so there is no problem in discharge.
4. Technical advantages of biological desulfurization
-Fully automatic unattended, highly stable and reliable.
-Deep hydrogen sulfide removal (outlet hydrogen sulfide content 50-100ppm)
-It can withstand the fluctuation of gas flow and sulfur load in a wide range
-Biogas will not be diluted by air: there is a strict physical separation between biogas and air
-Just a small amount of alkali, water and nutrients
-There is no risk of clogging and fouling and therefore less maintenance
-Normal temperature and pressure operation
-Production of elemental sulfur: it can be used as fertilizer and insecticide
5. Scope of application
Biogas bio desulfurization technology is widely used. Anaerobic treatment of sewage, manure, straw fermentation, high content of hydrogen sulfide in biogas produced by natural gas can be applied.
The above is a detailed introduction to the working principle and advantages of biogas bio desulfurization. For more information, please consult the website 。