In addition to SO2, coal combustion will also produce a small amount of SO3. SO3 concentration in flue gas is 10-40ppm. As the flue gas contains water (4% - 12%), SO3 generated immediately forms sulfuric acid mist. When the temperature is low, the sulfuric acid mist condenses into sulfuric acid, adheres to the inner wall of desulfurization and denitration equipment, or dissolves in washing solution. This is the main reason for the serious corrosion of wet absorber and related equipment. The treatment method is to use corrosion-resistant materials to make the absorption tower, such as stainless steel, epoxy glass fiber reinforced plastic, rigid polyvinyl chloride, ceramics, etc. Regardless of the desulfurization process, its environmental benefits are significant, but the economic benefits are uncertain.

许多脱硫方法都能获得较高的脱硫效率，但脱硫能力不均匀并不是评判脱硫方法优劣的惟一标准。除脱硫能力外，还取决于该方法的一般技术和经济状况。

Many desulfurization methods can obtain high desulfurization efficiency, but the uneven desulfurization capacity is not the only standard to judge the advantages and disadvantages of desulfurization methods. In addition to the desulfurization capacity, it also depends on the general technical and economic conditions of the method.

一般来说，应考虑以下几个方面:一是脱硫能力需要满足环保要求;选用先进的工艺和可靠的操作技术;选择投资低、运行成本低的技术;考虑废物处理和二次污染:吸收剂需要有稳定的来源、高质量和低价格，这是一个非常重要的因素。

Generally speaking, the following aspects should be considered: first, the desulfurization capacity needs to meet the requirements of environmental protection; Select advanced technology and reliable operation technology; Select technologies with low investment and low operation cost; Consider waste treatment and secondary pollution: absorbent needs a stable source, high quality and low price, which is a very important factor.

相对而言，我国石灰石资源相对丰富、纯度高、分布广，但高纯石膏的供应非常困难。副产品的处理需要一个场地和一个购物广场作为诱导使用;所用煤的硫含量对脱硫工艺也有影响。选择的重要因素需要是根据煤的含硫量来选择合适的脱硫方法。

Relatively speaking, China's limestone resources are relatively rich, high purity and widely distributed, but the supply of high-purity gypsum is very difficult. The treatment of by-products requires a site and a shopping mall as inducement; The sulfur content of the coal used also has an impact on the desulfurization process. The important factor for selection is to select the appropriate desulfurization method according to the sulfur content of coal.