Study On Heat Efficiency Of Furnace Chamber

With the reform and opening up,economic progress has reached a new field,energy consumption was large and environmental pollution was serious.As a result,our country pays mind to the problem,and energy saving and environmental protection are becoming a feather in many areas.A heating furnace is a type of high energy consumption device of a petrochemical company.To further improve the thermal efficiency of the heating furnace and reduce pollutant emissions,it is necessary to study the combustion of the heating furnace.This paper takes the SRT-III heating furnace of a petrochemical company as the research object.We will establish a computational model of the flow and heat transfer in the furnace and numerically study the heat transfer process in the furnace.The reliability of the model is verified by comparing and analyzing experimental data.Based on this,a study of the effects of operational and structural parameters on the thermal efficiency of heating furnaces at different black levels was simulated.The main contents and conclusions are as follows:(1)The establishment of the combustion model: According to the actual size of the SRT-III heating furnace,a 1/3 geometric model of the furnace is established,while the burner is simplified,and the furnace tube and burner are partially encrypted.Numerical studies of combustion and heat transfer processes in a heating furnace can express the temperature allocation in the furnace and accquire values for the oxygen substance in the smoke.The error is very small when compared to the data under real working conditions,indicating that the selected model is accurate.(2)Numerical study of furnace wall blackness on furnace thermal efficiency: Using means of numerical simulation,the effect of different furnace wall emissivity on the thermal efficiency of the furnace under a working condition is studied,and the velocity field is also studied.,temperature area and NO formation in the furnace.Research results indicate that as the emissivity of the furnace wall increases,the overall speed in the furnace changes uniformly,so it has no effect on the combustion.However,fuel combustion is promoted,the temperature in the furnace rises,which promotes the generation of NO,and the heat transfer in the furnace continues to increase,which improves the fuel utilization rate.In summary,with the increase of furnace wall blackness,the furnace thermal efficiency presents an upward trend,and the efficiency is higher than the actual working condition value.(3)Numerical study of operating parameters on furnace thermal efficiency: Under different furnace wall blackness,numerical simulation methods are used to study operating parameters: the influence of excess air coefficient,air preheating temperature,oxygen concentration and water vapor volume on furnace thermal efficiency.By analyzing the distribution of velocity field,temperature field,furnace heat transfer,there is no production of NO and no thermal efficiency in the furnace.The research results describe that when the excess air coefficient rises,the fuel can be burned,the temperature rises rapidly,the NO increases sharply,and the heat exchange in the furnace increases.However,excessive air is not conducive to fuel combustion and will cause uneven temperature field distribution.The tube has heat loss,the exhaust gas temperature increases,due to the decrease in NO,the thermal efficiency of the furnace indicates a straight current and then a straight downward current.In summary,it is best to select the excess air coefficient α=1.20;when the air preheating temperature increases,the max temperature in the furnace rises first and then falls.However,although the average temperature tends to rise,it rises relatively slowly after a certain temperature rise.The heat exchange in the furnace first rises and then decreases,and the thermal efficiency of the furnace also follows the same trend.At the same time,the amount of NO produced in the furnace is also greatly increased.In particular,too high a temperature will result in a doubled increase in the amount of NO produced.In summary,The air preheating temperature of 473 K is the best temperature;increasing of oxygen concentration accelerates the combustion rate and rasies the maximum temperature inside the furnace.But after the average temperature increases to a certain extent,the increase rate is relatively slow resulting in a linear increase in the amount of NO produced,and the heat transfer and furnace thermal efficiency also linearly increase.In summary,25% oxygen concentration is the best choice;the increase of water vapor causes incomplete combustion of fuel and less intense combustion,and the water vapor takes away a large amount of residual heat,which causes the maximum temperature in the furnace to decrease,the heat transfer in the furnace to reduce,and the heat efficiency of the furnace to decrease.small.In summary,the best choice of water vapor volume fraction is 5%.(4)Numerical study of furnace wall structural parameters on furnace thermal efficiency: Under the different emissity of the wall,the consequent of the structural parameters(shape of the radiation cell)of the furnace wall on the thermal efficiency of the heating furnace was trained by simulation,and a new type of radiating element was designed.Analyse the influence of the velocity place,temperature place,heat transfer and thermal efficiency in the furnace under different consequents.Research shows that with the increase of furnace wall blackness,the high-speed and high-temperature areas of flue gas in the furnace show an increasing trend,but the high-speed areas are concentrated in the normal direction of the radiating element and the high-speed area of the new radiating element is significantly larger,but the high-temperature areas are concentrated in the surroundings,The temperature in the normal direction of the radiating element is the lowest;when the furnace wall blackness increases from 0.6 to 0.95,the minimum furnace thermal efficiency of the new radiating element is 1.1 times the maximum thermal efficiency of the traditional radiating element.