| Through establishing experimental packing tower for flue gas desulphurization (FGD) by ammonia-ammonium sulfate method which used ammonia as absorbent,the absorption process of FGD,including the influence of L/G,pH value,composition and concentration of the absorption,velocity of the flue gas,concentration of the inlet SO2 on desulphurization efficiency,was investigated.The results showed that when the parameters is 2～3L/m3 for L/G,5.4～6 for pH,1.5～2.0m/s for the flue gas velocity,the desulphurization efficiency can reach over ninety percent.The predicting model of desulphurization efficiency based on the experiment was obtained by using response curved surface regression analysis technique which reflect the functional relationship between desulphurization efficiency and all the operation factors.Through the factor analysis of the model,the result that L/G has the most significant influence on the efficiency,and the interactions of L/G with pH value and flue gas velocity also plays a important roles in desulphurization efficiency can be concluded.The improved model of desulphurization efficiency was obtained by eliminating the factors which had little influence in the original model.The influence of forced-oxidation air capacity,concentration of(NH4)2SO3 and (NH4)2SO4,temperature,pH value on the oxidation velocity of(NH4)2SO3 was studied in the(NH4)2SO3 concentration range of 0.5 to 2mol/L.The results showed that high concentration of(NH4)2SO3 and(NH4)2SO4 can slow the oxidation velocity of (NH4)2SO3;high air capacity can obtain relatively fast oxidation velocity;the best pH value for(NH4)2SO3 oxidation is 5 or so;the activation energy of(NH4)2SO3 oxidation is 47.7kJ/tool.The oxidation kinetics equation of(NH4)2SO3 with high concentration was obtained on the basis of the experimental data.The effect of factors including pH value,temperature,addition of crystal seed,stirring speed and impurity on the crystallization process of(NH4)2SO4 was studied.The particle size distribution and crystal form of the product was also investigated.The investigation demonstrated that particles with comparatively big size can appeared under the process condition which was 5～6 for pH value,60℃for temperature,200r·min-1 for stirring speed and addition of crystal seed.(NH4)2SO4 generated four different crystal form when the four impurity Fe3+,Pb2+,Mn2+,Zn2+ existed.Finally,the ammonia desulphurization model of packed column was established based on the two-film theory.The model introduced chemical enhancement factor Ea and hatta number Ha.It reflected absorption process of SO2 dynamically;the calculation of mass transfer area can de divided into two pans:the packing area and liquid film area of tower wall.The results showed that change trend and datas between the calculation results and the experimental results is similar.This paper provided a theoretical basis for the industrialization of ammonia-ammonium sulfate FGD technology to some extent.
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