Study Of High Temperature Low Oxygen Combustion Process In Industrial Furnace With Exhaust Gas Auto-circulation

With its multiple advantages, such as high efficiency, energy saving and low pollution,high temperature air combustion technology is widely used in China’s industrial furnaceenergy saving, consumption reduction and emission reduction fields, and it has a hugeeconomic benefit and broad space for development.For further explore the characteristics of industrial furnace high temperature aircombustion, numerical simulation of the industrial furnace with exhaust gasauto-circulation combustion process was made by simulation software FLUENT, and theinfluence role on the flow field, temperature distribution and pollutants generated featuresof the conditions such as combustion air preheating temperature and oxygen concentration,swirl vanes and baffles was also analyzed. The results demonstated that increasing airpreheating temperature and decreasing oxygen concentration promoted the furnace gasmixing and dilution, conducive to making the temperature became more uniform, there alsoexist a best match between the air preheating temperature and oxygen concentration; addingswirl vanes and baffles can effectively organize the air jet and flow distribution, increasethe combustion intensity and the temperature level in the furnace, however, the increase oflocal high temperature is not conducive to uniform distribution of temperature field,resulting in an increase in NOXemissions, therefore the most appropriate angle and numberof swirl vanes, the size and number of baffles need to be determined according to the actualsituation.A high temperature air combustion system with continuous heat transfer was built, andthe variation of the temperature field and species concentration in furnace with airpreheating temperature was mainly analyzed. Though there were some differences betweenexperimental and simulation results, but the variation trend of the temperature and speciesconcentration are in a basic agreement. In order to solve the problem of low air preheatingtemperature of the shell-and-tube heat exchanger in the experimental system, a recuperatorhoneycomb ceramic heat exchanger is preliminarily designed, as well.