Study And Development Of A Gradually-varied Porous Media Burner

More importance is attached to the adjustment of energy constitution and the utilization of natural gas in China nowadays. And it becomes very significant to develop the technique of natural gas combustion with lower pollutants emission. The technique of fuel gases combustion in gradually-varied porous media (GVPM) has many advantages, and its application in natural gas combustion with higher efficiency and lower pollutants emission will be a blank-filling work in our country.In this paper, we are targeting to the realization of high efficiency combustion and low pollutants emission. The characteristics of combustion, pollutants emission, heat diffusion and resistance in the GVPM are mainly studied, on the base of which we designed the GVPM gas-fired boiler and put forward the research on the characteristics of heat diffusion and pollutants emission.The monotube-test system was established to study the performance of the GVPM burner. We discussed the startup characteristic of the GVPM burner with the monitor of temperature distribution, and found that the GVPM burner has the merits of lower NO_X and CO emission, higher heat diffusion and lower resistance, based on which we designed the GVPM gas-fired boiler.Experimental studies were done on the characteristics of the GVPM burner with two stages, and the results were compared with those of the monotube tests. It suggested that the temperature distribution was more uniform, and greatly contributed to the lower emission of NO_X, but was not as good as the monotube-test burner in the characteristics of startup and heat diffusion.On the base of the experimental research, we designed a water boiler with a GVPM burner was designed. Meanwhile, the design method of the gas-fired boiler was explored, and the construction parameters of each part were calculated.A testing system of porous media gas-fired boiler was set, and experiments were done. The gas-fired boiler was generally satisfactory according to the heat diffusion characteristic research, with wide range of load regulation. The maximum heat exchange efficiency of the boiler was about 99%, the smoke exhaust temperature was very low, and some water vapor coagulated. We obtained the emission law of NO_X and CO on the operating boiler through online measurement of pollutants emission with Rosement's continuous emissions monitoring system. There was also fairly low differential pressure within the work condition of the boiler.