Desulfurization Performance And Experimental Study Of Fly Ash/hydromagnesite Composite Desulfurizer

In this paper,the composite desulfurizer was prepared by mixing the ore powder of hydromagnesite in the Bangor Lake region of Tibet and the fly ash of the Xiaolongtang Power Plant in CHN Energy,and fly ash/hydromagnesite composite desulfurizer was used in the desulfurization experiment to study its desulfurization performance.First,the main chemical components of hydromagnesite were detected by X-ray diffractometer(XRD).Subsequently,in order to compare their desulfurization efficiency,the desulfurization experiments were carried out with hydromagnesite,magnesium oxide and calcium carbonate under the same conditions.According to the experimental data and theoretical analysis,it can be determined that hydromagnesite is feasible as a desulfurizer and has advantages.Then,the main chemical components of fly ash were detected by X-ray fluorescence spectrometer detection(XRF)and analyzed according to the test results combined with literature data,and finally the Xiaolongtan power plant fly ash sample was selected as an additive to the hydromagnesite desulfurizer.In this experiment,the fly ash/hydromagnesite composite desulfurizer was prepared under different conditions by means of hydration.And the specific surface area(BET)of the fly ash/hydromagnesite composite desulfurizer,original fly ash and original hydromagnesite was detected by specific surface area detector.Finally,according to the test results,a fly ash/hydromagnesite composite desulfurizer,with a relatively large specific surface area,is selected to conduct a flue gas desulfurization experiment in a bubbling reaction device.A four-factor four-level orthogonal test design was adopted in the experiment.The four influencing factors are liquid-solid ratio,bubbling depth,reaction temperature,and stirring speed,respectively.The data is then analyzed and compared with the desulfurization efficiency of traditional desulfurizers calcium carbonate and magnesium oxide.Through the study of traditional desulfurizers,the reason of different desulfurization efficiency for hydromagnesite,fly ash/hydromagnesite compound deslfurizer,calcium carbonate and magnesium oxide under different influencing factors was analyzed in detail by means of their specific desulfurization mechanism,chemical properties,diffusion model,and other theoretical basis,which combined with the wet simulation flue gas desulfurization experimental data in the thesis.The experimental results were shown in chart and other methods.From the experimental data can be derived:(1)As a desulfurizer,hydromagnesite is feasible.Under the same experimental conditions,the desulfurization efficiency of hydromagnesite desulfuriz er is the highest.The average desulfurization efficiency can reach 96.44%,which is significantly higher than that of calcium carbonate(83.96%)and magnesium oxide(91.07%);(2)The test results of specific surface area show that the specific surface area of fly ash is 2.353 m~2/g and the specific surface area of hydromagnesite is 8.902 m~2/g.Adding an appropriate amount of fly ash to hydromagnesite desulfurizer can increase the specific surface area of the composite desulfurizer.The optimal mass ratio of the compound desulfurizer is hydromagnesite:fly ash=8:1,and its specific surface area is 10.511m~2/g;(3)For the fly ash/hydromagnesite composite desulfurizer,the desulfurization efficiency of composite desulfurizer can reach 98.58%when the liquid to solid ratio is15:1,the bubbling depth is 2cm,the reaction temperature is normal,and the stirring speed is 150rpm.(4)The above four factors have different effects on the desulfurization efficiency of each desulfurizer,but the desulfurization efficiency of the fly ash/hydromagnesite composite desulfurizer is always the highest,because its specific surface area is relatively large,and the metal oxides in the fly ash can synergistically desulfurize with the composite desulfurizer and have a catalytic effect.