Experimental And Numerical Study Of MILD Combustion On EDC Model With Detailed Chemical Kinetic Reaction Mechanism

Combustion technology of high efficiency and low pollution is one of mainapproaches to solve current environmental and climatic problems. Mild combustiontechnology in the paper as a new combustion technology, realizes nitrogen oxides exhaustreduced by more than50%, thermal efficiency increased more than30%and equipmentsize decreased more than20%. However, at present the realization of Mild combustiontechnology requires higher air preheat temperature, which severely obstructs of itsindustrial application in a large scale. The key current is to research the realization of Mildcombustion mold and the characteristic of combustion under normal air temperature.A Laboratory-scale (20kW) Mild combustion furnace was aided designed with CFD toresearch Mild combustion on gas combustion and pulverized coal. The propane Mildcombustion mold was smoothly performed under normal air temperature upon the divice.The results showed that proper furnace average temperature and inlet air momentum werethe key factors to realize Mild combustion and that fuel and air at a position about a quarterof furnace off inlet had been adequately diluted by reflux flue gas, Circulation backflowrate is4.216. Though analysis on species field of Mild combustion furnace under normal airtemperature, it was found that the area with maximum content of CO in the furnace alwaysoccured in the maximum temperature area within the furnace and the area with minimumcontent of NO in the furnace always has a maximum content of CO. Pollutant content in theMild combustion flue gas under normal air temperature was very low, CO approximatelywas3ppm and NO40ppm。Via Mild combustion experience under variable air inlet temperature cases, it wasfound that, when raised air inlet temperature, the furnace temperature level increased, andcontent of CO and NO in the furnace flue gas increased with different extent.The CFD numerical simulation research results on Mild combustion showed, usingRSM model and EDC combustion model loaded three kind of detailed chemical reactionmechanisms. It declares that35steps detailed chemical reaction mechanisms could wellforecast temperature field and species field of Mild combustion. The predicted concentration of CO in the furnace Slight higher than measurements, NO concentration islower than the measured value. In the near burner area in the furnace, theforecast temperature is lower than the measured value; O2concentration is higher than themeasured value. This suggests that this area of the flow and burning scale can be very close,lead to emperature and oxygen concentration the simulation results in the area is inaccurate.forecast temperature is lower than the measured value; O2concentration is higher than themeasured value. This suggests that this area of the flow and burning scale can be very close,lead to emperature and oxygen concentration the simulation results in the area is inaccurate.