Study On Desulfurization Characteristics And Operation Parameters Optimization In Complex Spouted Flue Gas Desulfurization Technique

The semi-dry FGD technique with cycle fluidized bed has been widely applied in China. However, currently it still has many problems such as low desulfurization efficiency compared with wet FGD and weak load adaptability. To solve these problems, a new style complex spouted fluidized FGD technique is presented in this paper. The style bases on the flue gas desulfurization technique of circulating fluidized bed and uses multilevel spouted structure. SO2 in the flue gas is removed by classification and subsection. In the first-class tower, the liquid reaction is of priority with high fluidized speed and chemistry reaction process. In the second-class tower, the reaction section is prior to the aqueous particle chemistry reaction and the absorption solidification.To investigate the characteristic of the SO2 removal in this technique and optimize its technical scheme, the hot test system of complex spouted fluidized FGD was established. With online SO2 spectral analysis system, SO2 concentration was measured. In the first-class gas-liquid main reaction section, the influences of the absorbent, serum atomization quality, flue gas temperature, inlet SO2 concentration, circulation ash concentration, introduction manner of the serum et al on the desulfurization characteristics had been investigated. The result shows that the influence of the circulation ash concentration on the reaction section is prominent. It increases the desulfurization efficiency by 6%. Optimizing serum entry manner can raise the desulfurization efficiency by 3%. The serum atomization quality also influences the desulfurization efficiency by 2%─3%. In the second-class gas-solid main reaction section, the influence of the absorbent fed rate, flue gas temperature, disturbance intensity to the flow field, the internal circulation ash concentration and the regulation water flux et al on the desulfurization characteristic were also investigated. The result shows that the influence of internal circulation ash concentration on the reaction section is prominent. It raises the removal quotient by 18%. The fed rate of the absorbent, the regulation water flux and the disturbance intensity of the flow field also have remarkable influence on the removal ratio by 2%─6% in this reaction section. Compared with Cycle Fluidized Bed FGD, desulfurization efficiency is almost the same in the first-class. The removal ratio of the second-class to the whole can be raised by about 20%. The whole desulfurization efficiency can be raised from 5% to 10%.To investigate which factor among the flue gas temperature, overall water quantity fed into the tower, fed rate of the absorbent and atomization air ratio influences desulfurization efficiency mostly, orthogonal experiment method had been used. The results show that the influences of the overall water quantity fed into the tower and the fed rate of the absorbent on the desulfurization efficiency is remarkable, and the best combination of the factor levels has been obtained. In the tower, the resistance is almost proportional to the particle concentration. By considering investment cost and economic system operation, the desulfurization ash concentration in the second-class tower should control at about 600—800g/m3. When load falls, the velocity of the flue gas in the one-class tower is still kept high, which ensure the steady operation of the desulfurization tower. The load adaptability of this technique is better than normal tower with the same cross-section area along the tower height. It is obvious that this technique is of high advantages, and is an advanced flue gas desulfurization technique.