The Study On The Present Conditions Of Nitrogen Oxide Emissions Of Guangxi Cement Industry And The Emission Reduction Measures

This thesis reviewed the development of our country’s cement industry and relevant policies, demonstrated the main origins and damages of the Nitrogen oxides in cement industry and the technologies in controlling the emissions of the Nitrogen oxides in cement industry, analysed cement industry in Guangxi, including the pollutant emission and the operating conditions of the denitration facilities of the demonstration projects. Through denitrification facilities demonstration project of cement enterprises emission reduction efficiency and Guangxi cement enterprise specific circumstances have been built, and put forward the optimum scheme for Guangxi cement enterprise denitration,After forecasting the emission of NOx of cement industry in Guangxi, some suggestions were provided to reduce the emission. The results of the study are as follows.In2012, there are147cement enterprises in Guangxi, of which113shaft kiln and34new dry process. The total production is98,640,600tons in the region, cement industry NOx emissions is104,300tons, accounting for20.94%of the total nitrogen oxide emissions in the region; NOx emissions of new dry cement enterprises is10.35million tons, accounting for99.23%of the region’s cement emissions. Analysis of variance using the statistical software, the results indicate:The relativity of cement production and nitrogen oxides emission is very significant;and at the same cement products, new production process of nitrogen oxide emission of dry and emissions concentration was greater than the shaft kiln. Therefore, focusing on Guangxi cement industrial nitrogen oxide emission reduction measures should production process for the new dry process.Through analysis the denitration results of denitrification demonstration projec which have been completed in Guangxi, the main nitrogen oxides control technologies in cement industry are low NOx combustion technology, calciner staged combustion technology, selective non-catalytic reduction (SNCR) and Selective Catalytic Reduction (SCR) technology. The cost of low NOx combustion technology and calciner staged combustion technology investment cost is low, but the efficiency is only10%-20%; the SNCR technology is moderate costed and the denitration efficiency is about40-80%;a small amount of cement enterprises use SCR.Combining with the characteristics of production process of cement enterprise in Guangxi, and the operation of the denitration demonstration project which has been completed, put forward three schemes that suitable for cement industry denitration in Guangxi, and they were all achieve the National "twelfth five-year" emission reduction targets. From the emissions reductions of different schemes and the view of denitration facilities investment cost, we selected the optimal scheme by using principal component analysis and through comprehensive consideration. The results were:the enterprise which following the scale of2000tons/day don’t take the measures of denitration, but the enterprise which in the scale of2000to4000tons/day and more than4000tons/day all used the SNCR technology, and by2015, district would achieve89,600tons of emissions reductions. At the same time, the cost of sewage charges which avoid by reduce emissions far greater than investment cost of the denitration construction of cement enterprise.According to the situation and forecast of the nitrogen oxide emissions of cement industry in Guangxi, several measures of oxides emission reduction in cement enterprises of Guangxi were recommended.(1) According to the actual situation of Guangxi and the relevant state industrial policies, it is recommended that the existing2,000to4,000tons/day and4,000tons/day and above cement production line using selective non-catalytic reduction technology or low NOx combustion technological transformation combining selective non-catalytic reduction technology, and2000tons/day below lines using low NOx combustion technological transformation.(2) Implement the " Financial subsidy funds management approach of denitrification emission reduction projects of thermal power and cement enterprises in Guangxi ";meanwhile, formulate moderate tax release policy to encourage cement companies to operate denitration facilities.(3) Manage well the operation of denitration facilities, and create relevant files according to <The rules of accounting the total emissions of major pollutants>. Meanwhile, the specific measures in the operation of cement denitration facilities should be formulated to regulate the operation of denitration facilities.