Research On The Influence Of The Arrangement Of The Combustion Tube In The New Flat Flame Burner On The Combustion Characteristics

As an efficient and energy-saving combustion method,flat flame combustion is widely used in the metallurgical industry.It has the advantages of uniform combustion temperature,fast furnace heating and fuel saving.However,the use of air-assisted combustion will increase NO_X emissions and the efficiency of combustion heat is low.Therefore,the use of pure oxygen-assisted combustion can greatly increase the combustion intensity,reduce the burning time,avoid the generation of NO_X,and at the same time facilitate the capture of CO₂in the flue gas.Therefore,it is particularly important to design a new type of pure oxygen combustion-supporting flat flame burner.Compared with the traditional flat flame burner,the new flat flame burner has cancelled the gas-gas coaxial annular channel layout,and replaced it with gas swirl.The combustion tube is arranged tangentially above the burner,and the gas is adjusted by changing the distance of the combustion tube.The swirling intensity of the stream mixed with the combustion-supporting gas can control the combustion intensity and flame surface range.In this study,air and pure oxygen were used as combustion-supporting agents to conduct experiments,and the effects of the layout of combustion-supporting pipes,the distance of combustion-supporting pipes and the oxygen excess coefficient on combustion characteristics were analyzed,and the following laws were obtained:（1）Under the condition of air and pure oxygen combustion,both four-pipe tangent circle and three-pipe tangent circle arrangement can form a flat flow flame.Under the same combustion tube distance x,the air distribution under the four-pipe tangential arrangement is more reasonable,the flame area is larger,and the peak temperature,the temperature difference between the peaks and valleys,and the CO and NO emissions are lower than the three-pipe tangential arrangement.As the distance of the combustion-supporting tube increases,the peak temperature and CO peak value of the two arrangements continue to decrease.（2）Compared with air-assisted combustion,pure oxygen combustion has a lower swirl intensity than the latter,and the combustion area is smaller,the combustion temperature is high,but the combustion temperature fluctuation range is small.When the combustion tube distance x=60 mm,the peak value of CO for pure oxygen combustion is reduced by 57.4%compared with air combustion.（3）With the increase of the oxygen excess coefficient n,the swirling intensity of the fuel gas and oxygen mixed stream is increasing,the combustion process is more intense,and the flame surface is slightly reduced,but there is no significant difference in the combustion temperature and peak temperature.The CO peak value decreased continuously with the increase of the oxygen excess coefficient n,the oxygen excess coefficient n increased from1.06 to 1.24,and the CO peak value decreased by 28.7%.