Study On Removal Of NO_x Flue Gas With Coal-based Carbon In Different Thermal Fields

With the deepening of industrialization and urbanization,the urban air pollution in China is becoming more and more serious.The emission of nitrogen oxides in flue gas generated by coal combustion is increasing,and the environmental pollution is becoming more serious.Therefore,the corresponding measures must be taken to reduce the NOx emissions and reduce the harm to human life and the environment.The removal of nitrogen oxides in industry is mainly by using reductant(ammonia,urea,alkane,etc.)to mix nitrogen oxides for chemical reaction.However,the selective catalytic reduction method has the problems like high denitrification cost and by-product two times pollution,and the selective non catalytic reduction method has the problems,such as low denitrification efficiency and high temperature requirement.Therefore,it is the urgent desire of coal demand industry to find out a high-efficiency,green and low cost denitration technology.Semicoke is one of the coal-based carbon materials produced by low temperature pyrolysis of lignite,so the surface of the semicoke has well-developed pore structure and surface area during the low-temperature distillation process,and the carbon material has certain degree of reduction.In this paper,co-impregnation method of high efficiency and simple operation is used to produce different load-type catalysts and regarding semicoke as carrier and taking Na,Ni,Cu,Mn,K,Ca,Fe as the precursors.Then the mixed gas is used to simulate the flue gas,and the different supported catalysts are reacted under the conditions of conventional thermal field and microwave thermal field,and the best denitrification catalysts are found by comparing the completion of different supported catalysts under the same conditions.The results are as follows:(1)In the catalytic reduction experiment of coal-based carbon,the best performance of coal-based carbon material in four kinds of coal-based carbon materials was detected by denitrification,the best C-1 denitration performance in the conventional thermal field and the best C-4 in microwave thermal field.At the same time,it is found that the best reaction condition of coal-based carbon denitration is as follows:The starting no concentration is 400 ppm and the initial oxygen concentration is 5%.(2)In the conventional thermodynamic field,the optimum load of single metal is5% K,7% Fe,7% Ca,3% Mn,and the denitrification efficiency is 85%,80%,60%and 40% at 300 ?,respectively.The metal doping ratio of multi metal catalysts has influence on the catalytic reduction performance,the optimum doping ratios for the establishment of polymetallic catalysts are as follows: Fe 7% K 5%,Fe 7% Ca 7%,Fe7% Mn 3%,K 5% Ca 7%,and K 5% Mn3 %.The mixed metal catalysts with 5 % K7% Fe load have better denitration performance,lower denitrification temperature and89% denitration efficiency.(3)In the microwave thermal field,the load catalytic effect of 1% Na,7% Ni and3% Cu is better in the single metal load experiment,but the denitrification effect is unstable.After the mixed metal catalyst is loaded with coal-based carbon,it can promote the microwave denitrification.The best doping ratio of the polymetallic catalysts is established as follows: Na 1% Ni 7%,Na 1% Cu 5%,Na 1% Mn 5%,Ni1% Cu 3%,Cu 3% Mn 1%.The Na 1% Ni 7% mixed-load catalyst has the best effect on promoting the denitrification of coal-based carbon,and the denitrification power is low,among them,the removal rate of no is 95% in the thermal field of 250 w of microwave irradiation power.In a comprehensive way,the denitrification efficiency of coal-based carbon in microwave thermal field is higher than that in conventional thermal field,and the Na 1% Ni 7% mixed-load catalyst has high denitrification performance and stability,low reaction temperature and low carbon loss,which is an ideal catalyst for reducing NO_x.