Study on the Desulfurization Reaction Kinetics of Industrial Wastes

Desulfurization reactions of calciferous industrial wastes and limestone were studied by means of thermogravimetric analysis method.The modified grain model was used to describe the sulfation process and the kinetic parameters of the desulfurization reaction were calculated and analyzed.The results show that the grain model can effectually describe the sulfation process of the industrial wastes,and compensation effect of the kinetic parameters exists in the whole desulfurization reaction.The method based on isokinetic temperature(TS) to judge sorbent activity can be applied to different control stages of the sulfation course.The surface chemical reaction rate constants(k) of the chosen industrial wastes and limestone are all in the same order of magnitude approximately,however,the effective diffusion coefficients(Ds) of the wastes are bigger one order of magnitude than those of the limestone respectively.The reason for this is that the cation Ca2+ can diffuse and transfer to the product-layer surface of the sorbents,which greatly enhances sulfation reaction activity of the industrial wastes.The diffusion activation energy(Ep) of the wastes and limestone is bigger respectively than its own reaction activation energy(Ea),which shows that the product-layer diffusion is more difficult to carry out than the surface chemical reaction,and the product-layer diffusion is one decisive factor to control the whole desulfurization reaction.