Two-cycle Process For Desulphurization Using Slurries Of Phosphorite And Lime

China has a lot of industrial boilers, and their distribution is very wide. Along with their pollution to the air becoming more and more serious, developing desulfurization technologies of middle and small scale boilers and decreasing their exhausting quantity of sulfur dioxide is important and urgent work. In this paper, the desulfurization efficiency of a new type of tangent ring bar spray-bubbling tower has been studied. The reagent is phosphorite and lime, theoretical analysis on the complex mass transfer and chemical absorption has been carried out, the analysis and assessment of equipment performance was given with this experiment, and then the method proposed is proved feasible in practice. Contemporarily, experimental analysis on all operating parameters and their interaction has been studied, the comparison of their function extents are put out. The optimum performance region is presented. Finally, on the base of theoretical and experimental study, the merits and demerits of the tangent ring bar spray-bubbling tower are summarized, and the improvement methods are put out. Theoretical and experimental foundation for the design optimizing and commercial application is provided.In order to solve the problem of the tower that the gas distribution is uniform, the pass time of the gas is short and the desulphurization efficiency is low, the patent device of the tangent ring bar sprayed bubbling gas distributing broke the design pattern of tradition admission gear. It makes the gas enter into the tower through spraying and bubbling causes, makes the liquid as the continuous phase, the gas is the dispersed phase, and increases gas-fluid contacted area. Its own water power function causes to the even mix of all the substance. Configuration of the gas distributing device is simple, and it is not easy to block. It makes gas distributing,stir and demisting circulate at the same time, improves gas distribution greatly and enhances the desulphurization efficiency. The research believes that, the aperture area of the grid, the buried depth of the grid, the gas quantity and so on is the important affects of desulphurization efficiency.A process with two cycles and four absorptions in a tower using slurries of phosphorite and lime as absorbent individually was developed. The lower part of the tower is a injecting-bubbling column where phosphorite slurry is used as the absorbent After mixing the concentrated sulphuric acid with the phosphorite slurry which exits from the absorption cycle, phosphate fertilizer can be produced. Therefore, cost of the desulphurization and dust removal process can be reduced. The upper portion of the tower is an absorption tower combined with conventional spray tower and valve tower, and line slurry is used as absorbent to increase desulphurization efficiency. Results show that the important parameters which affected the desulphurization efficiency were pressure drop within the tower and the pH values of the absorbents. When pH value of the phosphorite slurry in the first circulation ranged from 3.5 to 4.5, the desulphurization efficiency remains stable. The desulphurization efficiency of whole process reached a maximum of 80% through the adjustment of the pH value of the lime slurry. Dust removal efficiency reached over 99.5%.