Study On Experimental Study On Reduction Of Nitrogen Oxide In Refractory Gas Furnace

Nitrogen oxide emission reduction is the focus of the country’s environmental protection.As the national requirements for nitrogen oxide emission standards become more stringent,refractory companies are facing increasing pressure to reduce nitrogen oxide emissions.For refractory companies,the existing nitrogen oxide emission reduction technology is not suitable,and there is an urgent need for a nitrogen oxide emission reduction method with good effects and suitable for the production of refractory materials.The research in this paper hopes to provide a reference for nitrogen oxide emission reduction methods suitable for refractory gas kilns.Therefore,this paper mainly conducted an experimental study on the formation of nitrogen oxides in refractory gas kilns.The experiment content is as follows:(1)The relationship between the formation of nitrogen oxides in the low-nitrogen oxygen premixed high-speed burner and the temperature was investigated on the bottom-lift elevator with different air surplus coefficientα;the air preheating temperature was compared with the low nitrogen oxygen premixed type Effect of high-speed burner nitrogen oxide generation;(2)Four traditional sleeve burners were tested in a 1 m3shuttle kiln in a simulated production workshop,the relationship between the concentration of nitrogen oxides and temperature was analyzed,and then compare the generation of nitrogen oxides between a single traditional sleeve burner and a low-nitrogen oxygen premixed high-speed burner,and analyze the reasons for the different concentrations of nitrogen oxides generated by the two burners;(3)Test and analyze the flue gas emissions of high temperature gas kilns and low temperature gas kilns of refractory companies;(4)Finally,the nitrogen oxide emission reduction methods of gas kilns in different temperature of refractory gas kiln are discussed.The conclusions are as follows:(1)Low nitrogen and oxygen premixed high-speed burner,the air surplus coefficient is different,and the production of nitrogen oxides is different.With the increase of the air surplus coefficient,the production of nitrogen oxides increases;when the temperature is less than 1400℃,the production of nitrogen oxides is lower,and the concentration of nitrogen oxides in the kiln less than 100 mg/m~3(the unconverted concentration is taken as the standard oxygen content of 9%),when the temperature is less than 1700℃,the nitrogen oxide concentration is less than300 mg/m~3;when the air excess coefficient is small,the concentration of nitrogen oxides less than 20 mg/m~3;for low-nitrogen-oxygen premixed high-speed burners,it is possible to reduce the formation of some nitrogen oxides by adjusting the air excess factor.(2)When the air preheating temperature is from room temperature to 550℃,the oxygen content in the combustion air gradually decreases.When the air preheating temperature is greater than 75℃,the oxygen content changes abruptly,and the oxygen content doesn’t change at 155℃;with the air preheating temperature with the air preheating temperature rises,the temperature of the flame gradually increases,up to 1680℃;the amount of nitrogen oxides generated is also positively related to the air preheating temperature.When a certain preheating temperature is reached,the amount of nitrogen oxides generated reaches a stable value,and the concentration of nitrogen oxides is less than 230 mg/m~3.(3)Four traditional sleeve type burners of shuttle kiln,the oxygen content in the flue and kiln is relatively stable;when the temperature is less than 1400℃,the amount of nitrogen oxides generated in the kiln is relatively small and the fluctuation is less than 150 mg/m~3;The concentration of nitrogen oxides in 1500℃is 200 mg/m~3;when the temperature is more than 1600℃,the concentration of nitrogen oxides more than 300 mg/m~3,the combustion flame is unevenly distributed,there are many bright areas and local high temperature areas,and the flame fire column sometimes shakes discontinuously and is unstable.(4)The single burner of the shuttle kiln,the oxygen content in a single traditional sleeve burner kiln and the flue are relatively stable;under the same conditions,the generation of nitrogen oxides of the premixed high-speed burner is comparable to that of the traditional sleeve burner the ratio is reduced by more than40%,the flame has no obvious flame bright area,the combustion flame does not drift,and the fire column is stable.(5)The concentration of nitrogen oxides in the high-temperature gas tunnel kiln and flue of the selected refractory company is high,and there is no obvious rule;the nitrogen oxide kiln is 600 mg/m~3,the flue is 500 mg/m~3;The low temperature kiln oxygen content and nitrogen oxide content are relatively stable,the kiln is less than 250 mg/m~3,and the nitrogen oxide in the flue is less than 400mg/m~3;The conversion concentration of nitrogen oxides in medium and low temperature gas kilns with operating temperature<1400℃is less than 110 mg/m~3,and the conversion concentration of nitrogen oxides in the flue is less than 225mg/m3,the first-level dry physical and chemical composite adsorption efficiency can reach more than 70%.(6)Low nitrogen oxygen combustion technology is the direction of development.Gas kilns at temperatures below 1400°C are expected to use low nitrogen oxygen premixed high-speed burners combined with organization combustion technology to reduce the generation of nitrogen oxides by 40%at the source and achieve ultra-low emissions;Gas kilns with a temperature higher than1400℃can adopt the method of“source treatment+exhaust gas purification adsorption”to achieve ultra-low emission of nitrogen oxides.