Comparison of wet flue gas desulfurization methods

Thread Content

The wet oxidation method is widely used in domestic ammonia synthesis plants that use coal as raw material, as it can not only remove H2S from the feed gas but also produce sulfur as a by-product, while featuring fast reaction speed and high purification efficiency. The commonly used methods for wet oxidation include the modified ADA method, the tannin method, and the ammonia aqueous phase catalysis method. These methods are well-developed in terms of technology; in particular, the tannin method not only has low operating costs but also avoids the problem of blockages in desulfurization towers, which is why it is widely used in China. The ammonia aqueous phase catalyst method is more suitable for desulfurizing coke oven gas; it can utilize the ammonia present in the coke oven gas as an absorbent, and it is also capable of removing HCN, making it relatively economical. The most commonly used desulfurization methods in some ammonia synthesis plants that use natural gas as a raw material are the alkoxyalcohol-ammonia method and the methyldiolamine desulfurization method. For ammonia synthesis feed gases with high levels of acidic gases such as H2S and CO2, in order to prevent environmental pollution caused by H2S, physical absorption or physicochemical mixed solvent absorption methods are suitable. Such as the low-temperature methanol process and the NHD process. The H2S gas released during the desulfurization night regeneration is used to recover sulfur via the Claus process.