The Formation Of NOx In Cement Industry And The Research To Control The NOx

NO_x is one of the main pollutants from cement kilns, it is extremely serious harm to the the atmosphere environment. The latest census in 2007 showed that the NO_x of concentration of new dry process cement kiln accounted for more than 800 mg/Nm³ 13%, more than 500 mg/Nm³ less than 800 mg/Nm³ accounted for 57%. Cement production calculated according to the present, the national cement industry in NO_x emissions of about 1.7 million tons (1 ton of NO_x caused by the greenhouse effect is equivalent to more than 200 tons CO2), accounting for the total NO_x emissions by more than 40%.The topics to new dry process cement production based on the theory of the formation of cement clinker during the formation of NO_x rules and factors to explore the formation of reducing the amount of cement kiln NO_x combustion conditions and the curing of cement kiln NO_x emissions, absorption and the reduction approach and cement kiln NO_x emissions reduction technology development and application; from living under the catalyst temperature and the best selection of appropriate reaction temperature catalytic reduction catalyst research, in order to obtain high catalytic activity at low temperature, reducing the efficiency of more high catalyst.The cement kiln NO_x formation and distribution law, this paper use the theory of fluid mechanics and numerical simulation technology with features of the formation of cement clinker, cement kilns within the simulation of NO_x formation mechanism and distribution.According to the simulation results, cement rotary kiln for the thermal NO formation is mainly type-NO and fuel NO, fuel-NO mainly in the kiln head of the firing zone and decomposition with generation, high-temperature thermal NO mainly produced in the burning zone, which is the current consistent with the theory; Cement kiln NO_x reduction in exploration methods, we study the solidification and reduction methods, solidification method used in the coal, raw materials and a mixture of coal and raw materials by adding the appropriate chemicals to the chemical the material and the formation of NO_x in the flue gas produced by the reaction of nitrogen salts, experiments show that these three kinds of methods to add chemical substances in coal can be better to nitrogen fixation:KOH added to the major coal generation K₃NO₅,K₃NO₄,coal added K₂CO₃ powder produced mainly KN₃, adding K₂SO₄ major coal generation K₄O (NO₂) 2, KNO₂. For the reduction, of the two ideas are in the raw meal by adding reducing agent and in the raw meal by adding reducing agent and catalyst, coal as raw material by adding the effect of reducing agent than the effect of adding activated carbon as the reducing agent is better.Raw meal by adding pulverized coal at 750℃of denitrification efficiency reached 100% in this temperature, the raw meal by adding activated carbon and denitrification efficiency is only 9.0%. A mixture of raw meal and the reducing agent adding an appropriate amount of catalyst can accelerate the reducing agent on the NO reduction rate, the experimental results obtained, reducing agent is not the same catalyst at the same time, V2O5, CuO as a catalyst is better, the same reduction catalyst agent is not the same time, coal as a reducing agent is better.