Research On The Novel Type Of Composite Synergistic Aadditive For Wet Flue Gas Desulfurization

Thermal power generation, as an important component of Chinese power generation industry, accounts for more than 80 percent of the Chinese power generation structure. SO2 pollution caused by burning coal causes a serious influence to the atmospheric environment. In order to meet the increasingly stringent environmental requirements, the improvement of SO2 pollution caused by coal-fired power plants has become a significant task within the industry. The wet flue gas desulfurization(WFGD) has been the most common method adopted by coal-fired power plants. On the basis of non-modification of the original desulfurization equipment, the use of a new type of desulfurization additive to improve the desulfurization efficiency is one of the most reasonable ways.In this study, the influence of mono-component additives on the limestone dissolution rate and the rate of oxidation of calcium sulfite were investigated, and the influence mechanism of different mono-component additives on desulfurization efficiency was revealed. According to the economic cost analysis, several kinds of mono-component additives with better performance indicators were selected, and then the influences of multi-component additives with different mixing ratios on the desulfurization efficiency were explored. The optimal conditions for the use of additives were obtained. At last, field experiments were carried out in the power plant to investigated the on-site effect of the multi-component additives.The results show that Glutaric acid has the best effect on promoting the limestone dissolution. The ratio can be increased by 9.6% compared with conditions without additives when p H is 5.5. Many inorganic materials have different effects on oxidation of calcium sulfite, such as FeSO4, CuSO4, MnSO4, MgO. Eight kinds of multi-component composite additives are developed based on the results, among which No.6 additive is effective in both accelerating limestone dissolution and enhancing oxidation of calcium sulfite. The optimal conditions for the use of No.6 additive is that pH is kept between 5.2 and 5.8, and the concentration reaches 600 mg/L to 900 mg/L.The field experiments show that: with the use of the developed composite synergistic additives, the desulfurization efficiency can be enhanced by 2%-3%. Through the shutdown of some parts of slurry circulating pumps, it effectively reduces the operating cost. Economic analysis shows that:if a power generation equipment with 2*600MW shuts down a slurry circulating pump,the operational cost can be saved by approximately four million Chinese Yuan per year through saving energy and reducing consumption as well as the cost savings of limestone.