Coal gas is a kind of gas fuel which is made from coal and contains combustible components. There are many kinds of gas and its components are complex. It can be divided into artificial gas and natural gas. As one of the main energy sources in China, producer gas is widely used in various industries . The purification of gas is not only the purification of tar content, dust content and water content, but also the sulfur content in gas. Therefore, we need to understand the importance and methods of gas desulfurization.
The main components of the gas are carbon monoxide, methane, carbon hydrogen compounds, hydrogen, nitrogen, carbon dioxide, and a small amount of dust, water, sulfur, tar, naphthalene, ammonia, benzene and other impurities; the sulfur in the gas mainly exists in the form of hydrogen sulfide (H2S) and sulfur dioxide (SO2), most of which exist in the form of hydrogen sulfide, and hydrogen sulfide is converted into disulfide with the combustion of the gas Sulfur dioxide is discharged in the form of sulfur oxide, which combines with water vapor (H2O) produced by combustion to form sulphurous acid (H2SO3), which not only corrodes the metal surface, but also causes serious pollution to the atmospheric environment and affects human health. If gas is used to make steel, the quality of steel will be reduced, and sulfur dioxide has a greater impact on the product quality of ceramics, glass and kaolin industries.
Combined with the above factors, gas desulfurization has become an important indicator of its cleanliness. No matter from the perspective of environmental emission or product quality, this part of hydrogen sulfide in gas should be removed. Gas desulfurization can not only improve the quality of gas, but also produce sulfur or sulfuric acid for comprehensive utilization.
There are two kinds of gas desulfurization methods: hot gas desulfurization and cold gas desulfurization. In our country, hot gas desulfurization is still in the experimental research stage, while cold gas desulfurization has relatively mature technology. In general, cold gas desulfurization can be divided into dry desulfurization and wet desulfurization. Iron oxide method and activated carbon method are widely used in dry desulfurization, while arsenic alkali method, ADA, modified ADA and Castanopsis method are mainly used in wet desulfurization.