The semi dry process reflects the different selection of the whole desulfurization process and desulfurization materials, especially the semi dry process of desulfurization in wet conditions and solving desulfurization materials in dry conditions. It not only has the advantages of sensitive response and high desulfurization efficiency of wet desulfurization process, but also has the advantages of dry desulfurization process without sewage and wastewater discharge and solving desulfurization materials in dry conditions. It is the key development prospect of sulfur removal process.
The spray semi dry method uses the basic principle of the spray dryer to spray the adsorbent slurry to the desulfurization tower. In the desulfurization tower, the adsorbent changes chemically with the sulfur dioxide in the flue dust. In addition, the heat in the flue dust is digested and absorbed to make the water in the adsorbent evaporate and dry, and the waste after desulfurization is discharged in a dry state.
The process steps are simpler than dolomite gypsum method, and the project investment is also small. The defect is that the desulfurization rate is low, generally 70-80%, the actual operation ductility is small, the calcium sulfur is relatively high, the operation cost increases, and the by-products cannot be used.
2、炉内喷钙尾端加湿活*法
2. Calcium Spraying in furnace, tail end humidification method
The ground limestone powder is sprayed into the area with the temperature of 900 ~ 1250 ℃ at the upper end of the furnace by means of pneumatic conveying system. CaCO3 is dissolved immediately and reflected with SO2 and a small amount of SO3 in the smoke and dust and transformed into CaSO4. Cao not reflected in the inner furnace is converted into Ca (OH) 2 by reaction with the injected water, SO2 is converted into Ca (OH) 2 by rapid response and converted into CaSO3, and some of it is oxidized into CaSO4.
The advantage is that the investment of machinery and equipment projects is small. However, under the standard of calcium injection in the furnace, CaCO3 is thermally cracked and converted into basic enzyme Cao. Although it is impossible to obtain a high desulfurization rate in the furnace immediately, Cao not reflected with SO2 in the furnace is watered and hydrated to Ca (OH) 2 at the back of the heating furnace. It can be reflected with SO2 again at ultra-low temperature, which can significantly improve the desulfurization rate of system software and the utilization rate of calcium based sorbent, but the desulfurization rate is generally 60% ~ 70%. On the whole, the desulfurization rate in the furnace and the utilization rate of calcium based sorbent are not high enough, and the competitiveness of its technical and economic development characteristics is not strong enough.
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2022-05-09
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