Experiment Alstudy On Properties Of Unslaked Lime Dry Hydration Based Semi-Dry Desulfuriza Tionprocess

As the Dry Hydration Technology system has the advantages of simplicity,lesswaterconsumption,and higher activity of slaking products,it has become a hotissue in the field of absorbent preparation technology for semi-dry / drydesulfurization. Pre-existing research related to hydration technology mainly aimsat practical engineering problems, and mechanism analysis of dry slaking process islacked. Besides,Dry Hydration Technology used in Desulphurization Industry atpresent is not mature,and there are still many problems for mid-scale experimentalstudy. Therefore,further investigation of the impacts of dry hydration conditions oncaustic lime slaking process and products to improve dry hydration system hassignificant meanings.In this paper,an experimental system for dry lime hydration is set up,andimpacts of the hydration conditions(H2O/CaO, hydration water tempreture,limeparticle diameter,stirring intensity,water–supplying rate)on caustic limehydration process and product are studied to obtain the correlated relations. Itindicates that H2O/CaO and stirring intensity have a significant effect on dryhydration process,they are both the key parameters for controlling the systemtempreture and conversion ratio of caustic lime. They not only influence theutilization effects of Calcium-based desulfurizer,but also closely related tooperational safety of hydration system. The experimental results indicate the bestoperating parameters are:H2O/CaO Moore ratio 1.6,stirring rate 12-40 r/min.Initial temperature of hydrating-water has no obvious impacts on caustic limeconversion,but has an significant influence on the activity of the hydration product.The higher initial temperature of hydrating-water is conducive to get more activedesulfurizer. Lime particle diameter has unobviously affects on the rate of causticlime hydration and the conversion ratio. Smaller particle diameter promotes the dryhydration process, and the best particle diameter is 75μm.Water-supplying rate hasno significant effects on caustic lime conversion, particle diameter and surfacestructure and morphology of the hydration products. However, hydration rate can becontrolled by varying water–supplied rate.Based on the above studies,the characteristic of the impacts of semi-drydesulfurization process on caustic lime dry hydration is also analysed. It is studied that the effect of dry hydration process and the conversion of caustic lime by thedesulfurized ash and desulfurization product CaSO3,and the surface topography ofslaking products with different additives are studied.It indicates that on the one handaddition of desulfurized ash promotes moisture to be mixed uniformly,which canprevent the emergence of local area high or low humidity,thus prevent Scaling andslaking nonuniform occurs,on the other hand it can promote the surface layer of theproduct peeling during hydration process. Compared with desulfurized ash,fly ashplays a similar role on hydration of caustic lime. While the way of adding CaSO3which is used in this paper has inhibiting effect to the hydration of caustic lime.