Experimental Study On Organic Wasterwater As Denitration Agent For Cement Kiln

Research on treatment methods for refractory organic wastewater has been a hot spot for recent research and development.Combined with the concept of sustainable development,In this paper,organic wastewater is used as denitration agent in cement kiln and related research is carried out.Firstly,The denitration effects of seven common wastewater(1#wastewater of addition reaction,2#etherification mother liquor,3#coking wastewater,4#slaughterhouse wastewater,5#landfill leachate,6#degreasing puree,7#oxy bridge magma)are investigated in a tubular heating furnace.At the same time,two kinds of organic wastewater with better denitrification effect are used to simulate denitrification experiments in a hot coal-fired furnace,the factors such as oxygen content,nitrogen oxide concentration,residence time,reaction temperature and optimum C/N ratio are taken as experimental indexes.Finally,in the Qinglian Qilianshan Cement Plant,landfill leachate is used instead of part of ammonia to carry out SNCR denitrification transformation.The denitrification efficiency,total organic carbon emission increment,conventional pollutant discharge,dioxin emission,CO emission and cement quality are carried out before and after the transformation.There are two different denitration peaks in the tubular heating furnace.When the temperature is raised from 800℃to 1000℃,the denitration efficiency of 1#wastewater is reduced from about 50%to less than 20%;The TOC,COD and ammonia nitrogen of2#wastewater are at a lower level,Vaporization pyrolysis exacerbates coal consumption;The denitrification efficiency of 2#wastewater is only about 20%;The ash residue after denitration of 6#wastewater is more than others;7#Wastewater has a pungent odor.3#and 5#were selected for the denitration experiment on hot coal fired furnace.The exploratory reasoning of the denitrification mechanism of organic wastewater:the long-chain pyrolysis of organic matter in wastewater is short-chain,and the short-chain continues to pyrolyze into H·,CH·,HCCO·,CO·and other particles,and further reacts with NO to achieve denitration effect.In the hot coal-fired furnace experiment,when the injection mass ratio of 3#wastewater is 13.0,the temperature is 993°C,the oxygen content is 4.47%,and the flue gas residence time is not less than 0.73 s,the optimal denitration efficiency is 49%;When the injection mass ratio is 14.6,the temperature is 1032°C,the oxygen content is4.47%,and the flue gas residence time is not less than 0.73 s,the optimum denitration efficiency of 5#wastewater is as high as about 54%.5#Wastewater has a wider denitration temperature window,higher denitration efficiency and lower calorie consumption than 3#wastewater.If denitrification is carried out on the cement kiln,When the volume ratio of landfill leachate to ammonia water is 2:1,the flow rate of the mixed denitration agent is0.51 m3/h,and the average denitration efficiency in the cement kiln is 54.8%.In addition,the dioxin emissions of the mixed denitrizer decreases by 0.037 ng TEQ/m~3compared to the ammonia denitrification agent;at the same time,the emission of TOC has not increased significantly;the cement quality and quality control are in line with national standards.Denitrification of wastewater can effectively reduce the emission of nitrogen oxides and alleviate the phenomenon of ammonia escape;can effectively utilize the organic and ammonia nitrogen in organic wastewater,save the ammonia reducing agent,Increase Economic Benefit.