ANALYSIS OF WASTE GASES CLEANING METHODS FROM SULFUR DIOXIDE

Abstract

It is shown that sulfur dioxide is one of the most common components of harmful emissions into the atmosphere. It is stated that a large amount of SO2 is emitted into the atmosphere in the production of sulfuric acid, during fuel combustion in thermal power plants, and in modern production of surface-active substances. It has been shown that sulfur dioxide is responsible for the formation of acid rain, which is one of the most common forms of pollution around the world. It is stated that all known methods of waste gas purification are divided into three main groups: ammonia methods, SO2 neutralization methods, catalytic methods. In general, absorption methods are divided into open and circulation cleaning schemes. It is shown that ammonia-acid methods are economical, but require consumption of a scarce product - ammonia. The ammonia-sulfuric-acid method consists in treating ammonium bisulfite with sulfuric acid. When using the ammonia-phosphoric-acid cleaning method, phosphoric fertilizers and SO2 are formed, which can be further processed into sulfuric acid. The sodium method is based on the absorption of sulfur dioxide by a CaO suspension. It is indicated that when using a solution of sodium hydroxide as an absorbent, both open and circulating cleaning schemes are used. It is shown that catalytic methods of waste gas purification do not require the use of an absorbent. However, it is necessary to use an expensive catalyst. Most often, this method is used at the first stage of cleaning, and at the second - the cleaning methods listed above. The table with comparative technical and economic indicators is presented, the choice of one or another cleaning method depends on specific production conditions. It is shown that for the production of surface-active substances it is better to use open cleaning schemes, which are distinguished by the simplicity of the equipment design, as well as the low consumption of energy for cleaning. It is stated that sodium hydroxide solution can be chosen as an absorbent. If the sodium hydroxide solution contains small amounts of sodium sulfite, it can be used as a neutralizing agent in the neutralization of sulfation products.