Study On Catalyzing And Desulfurization Additives Of Power Coal

Coal is China's primary energy, and it will play an important role for a long time in the future.There are two problems of coal combustion,the first is, the high carbon content of fly ash and the low energy efficiency caused by incomplete combustion of coal; The other is serious air pollution caused by a mass of sulfur dioxide by coal-burning emissing.On this basis, this paper carried out the study of the catalyzing and desulfurization additives of power coal, in oder to utilize coal in clealy and high efficiently way.In order to taking full advantage of the low grade power coal resources which is from south of Hunan and which has high sulfur and ash proportion, selecting the small fluidized combustion bed will be mainly development direction. This research selected symbolic high sulfur and ash proportion coal called Jiali coal as the object of the experiment, studying on the effect of catalytic and desulfurization of alkali metals,alkaline metal and transition metal oxides and salts:Na₂O₂, NaCl, Na₂CO₃, NaNO₃, CaO, MgO, Ba(NO₃)₂, MnO₂, Fe₂O₃, ZnO and Fe(NO₃)₃ on the conditions of fluidized bed combustion and using thermogravimetric analysis methods.We have the conclusion that Na₂O₂, NaCl, Na₂CO₃, NaNO₃, CaO, MgO, MnO₂, Fe₂O₃, Ba(NO₃)₂ and ZnO all had good catalyzing and desulfurization effect,and the desulfurization experiment showed that the oder of the effect of desulfurization from strong to weak were: ZnO, Ba(NO₃)₂, NaNO₃, MnO₂, CaO, Fe₂O₃, Na₂CO₃, NaCl, MgO, Na₂O₂, Fe- (NO₃)₃;and the effect of catalyzing from strong to weak were as follows, MnO₂,NaNO₃,Fe₂O₃,NaCl,CaO,MgO,ZnO,Na₂CO₃;Colligate the conclusion of the research before and this disquisition,We developed two kinds of catalyzing and desulfurization additives of power coal which were low-cost and high efficiency, ADD-1 and ADD-3. When the addition of ADD-1 and ADD-3 weighed as 5% (mass),the desulfurization rate was 38.2%,37.8%,the burnout ratio increased from 44.91% to 51.21%,55.10% respectively, the ignition temperature of coal sample decreased from 449oCto 441oC,438oC respectively, the maximum burning rate increased from 0.310%/oC to 0.357%/oC,0.401%/oC respectively.Catalyzing and desulfurization additives of power coal mechanism was studied by using coal combustion kinetics and SEM analysis.We obtained that catalyzing and desulfurization additives of power coal have reduced the activation energy Ea in coal combustion process,made combustion reaction running in lower energy; It can change the pore structure of coal ash, made coal dust ash loose, that will be helpful for sulfur dioxide diffusion, it can aslo have chemical reaction with sulfur of coal and the constituent had synergy mutally.So catalyzing and desulfurization additives can improve the afects of sulfur-captured and combustion-catalyzed of power coal.