Research On Sodium Sulfate Separation Technology Of HPP-H₂SO₄ Absorption Solution In The Desulfurization Industry

Based on the system of HPP/H2SO4 solutions, the reinforcements of adding into the solutions on thermal absorption and desorption process are studied. For the lack of the solubility data about Na2SO4, studies were carried out by the method of hydrostatic equilibrium, on the basis of a large number of experiments. The solubility of Na2SO4 in different concentrations of HPP solution was detected, from 273.15K to 373.15K.The results indicated that the solubility of Na2SO4 with the increasing of the concentration of HPP, decreased at the same temperature. In the solution of HPP,at some temperature and concentration of Na2SO4,the phenomenon of salting out and solution-delamination emerged, and the solubility of Na2SO4 increased. The distribution coefficient of HPP increased with the temperature increasing and the concentration of Na2SO4.The the relationship of the cloud point and Salt Point with the HPP, Na2SO4 and temperature was calculated and polynomial fitted.The results show that the solubility of Na2SO4 in the HPP solutiong with 0.5 mol/L H2SO4 is the lowest comparing 1.0 mol/L 1.5mol/L,2.0mol/L. The solubility of Na2SO4 reduces with increasing of the concentration of solvent in the solution,when the of molar ratio is 2:1 betweent HPP and H2SO4.The metastable zone widths of the Na2SO4 were investigated at different temperatures, agitating rates, cooling rates. Results indicate that the width of metastable zone increased with decreasing temperature and agitation rate. The influences of the HPP and H2SO4 on t metastable zone widths were investigated, separately. With the increase of the concentration of HPP, the metastable zone decreased.And with the increase of the concentration H2SO4, the metastable zone increased.Single factor experiment method is employed in studying the effects of the crystal such as the temperature, cooling rate, the stirring rate, and the amount of crystal on the process. Results indicate that the yield of Glauber’s salt increased with the endpoint temperature decreasing. The cooling rate, stirring speed, crystal adding had no obvious effect on the yield. The main particle size decreases with the decreasing of the temperature, and increases with the decreasing of cooling rate and stirring speed.