Research On Structure Optimization And Pollutant Emission Control Of Industrial Porous Medium Burner

Compared with the traditional gas combustion technology,porous media combustion has the advantages of full combustion with near zero CO emission,no local high temperature with the NOx emission as low as 30 mg/m~3,uniform heating with the temperature difference of±3℃and stable combustion suitable for various low calorific value gas.In the present paper,the basic performance and application performance of porous media combustion are systematically studied,and feasible methods are proposed in terms of pollutant emission control.The main research contents are as follows:1.The stability range,combustion characteristics and pollutant emission characteristics of double-layer porous media burners with different structures,combustion intensity and excess air coefficient are investigated in a porous media combustion experiment system.The structure of porous media materials has little influence on the range of combustion stability.The upper and lower limits of combustion stability increase with the increase of equivalent ratio,and the range of combustion stability widens with the increase of equivalent ratio.The adjustment ratio of burner can reach 11.4:1.The change of combustion state of porous media is related to combustion power and excess air coefficient.Increasing combustion power and decreasing excess air coefficient can shorten the time for the porous media to change from surface blue flame combustion to immersed infrared combustion.The CO emission of porous media burners is nearly zero.The NOx emission decreases with the increase of excess air coefficient.When the excess air coefficient is greater than 1.3,the NOx emission is lower than 30 mg/m~3.Si C foam porous media burners have lower NOx emission concentration in excess air coefficient between 1.3 and 1.6.2.In order to improve the industrial safety of porous media burners,the outlet structure of porous media burners is optimized,and the influence of different combustion states on the stability of fire detection signal and the emission characteristics of pollutants are studied.The fire detection signal value at the surface of the hybrid porous media burner is stable,much higher than that at the infrared radiation,which effectively improves the safety and stability of the porous media burner.The hybrid porous media burner can realize the change of combustion state faster.When the combustion surface power is 2.0 MW/m~2and the excess air coefficient is 1.2,the burner can reach the infrared radiation combustion state within 30seconds.Similarly,hybrid porous media burners have near zero CO emission and very low NOx emission concentration at large excess air coefficient.3.The combustion characteristics of the porous media burner under the actual combustion condition are studied,and compared with the traditional low nitrogen burner through the application test of the porous media burner in the oilfield heating furnace.The porous media burner has excellent fire stability and high safety performance.NOx emission is as low as11.8 mg/m~3,with an emission reduction rate of 90%.And the energy saving effect is remarkable,the energy saving ratio is up to 50%,giving play to the advantages of porous media energy saving and emission reduction.