Research On Low Nitrogen Combustion Characteristics Of Organic Heat Carrier Furnace

With the increasingly restrictive national policy on energy and environmental,coal-fired organic heat carrier furnaces have begun to transform into gas-fired organic heat carrier furnaces,and natural gas produces NO_x when it is burned.In order to reduce NO_x emissions in organic heat carrier furnaces,this paper developed a new type of low-nitrogen burner,and carried out test and simulation on it.The influence law of low nitrogen combustion characteristics in the heat carrier furnace,the main work and conclusions are as follows:(1)Low-nitrogen combustion mechanism and design: First,a new type of low-nitrogen burner was designed and developed according to the low-nitrogen combustion mechanism,and the Fluent numerical simulation of the new type of low-nitrogen burner was conducted.The flame is made up of two main parts.By dividing the flame shape,the combustion characteristics are improved.Then,a cold state experimental study was carried out.It is found that the velocity magnitude on the truncated line decreases with increasing axial distance and that the velocity distribution has a "saddle shape".Finally,the experimental and simulation results were compared to within 10.5 % error,providing theoretical support for subsequent numerical simulations.(2)Influence of burner structure parameters on low-nitrogen combustion characteristics of organic heat carrier furnaces: By adjusting the swirl angle of the burner swirl sheet and the number of fuel injection holes,the effect of structural parameters on the combustion of organic heat carrier furnaces is studied.influence of characteristics.As the angle of deflection increases,the average temperature first rises gradually and then begins to fall.The inflection point is when the angle of the swirl vane is 30 degrees.At this time,The average temperature at the cross section was a maximum of 1227 k and the NO_x concentration at the outlet was 34.48ppm;the study found that the overall temperature of the main combustion stage when the number of nozzle holes is 3 is higher than that of the other three working conditions,and the average temperature of the highest section reaches 1227 k.When the number of holes is 4,nitrogen oxide concentration only 30.19 ppm.(3)Influence of burner operating parameters on the low-nitrogen combustion characteristics of organic heat carrier furnaces: change the proportion of secondary combustion stage gas,excess air coefficient,and air preheating temperature of the low-nitrogen burner to study the effect of operating parameters on the organic heat transfer furnace.Influence of heat carrier furnace combustion characteristics.As the proportion of secondary combustion grade gas increases,the average cross-section temperature of the organic heat carrier furnace gradually decreases,and the NO_x concentration at the outlet increases first and then decreases.When the secondary combustion grade gas proportion is 0.4,the outlet NO_x concentration is the lowest,only 29.1 ppm;When the excess air coefficient is 1.2,the NO_x(ppm)at the outlet is the smallest,about23 ppm.As the air preheating temperature increases,the overall average temperature in the furnace will increase accordingly,and the corresponding outlet NO_x concentration will also increase linearly.