Experimental Study on the Performances, Energy Efficiency and Emissions of Porous Burner

บทคัดย่อ

This research is to experimentally study the performance of a porous burner (PB) and the results are compared with those obtained from the conventional burner (CB). The porous burner consists of two co-concentric cylindrical tubes as a shell and tube heat exchanger. The inside of a tube fills up with spherical ceramics with a diameter of 1.5 cm for forming the porous chamber, which is wrapped around by a larger cylindrical tube as a shell. The shell contains water and serves as a water container. The LPG is used as a fuel and a heat-load condition is set as the gas flow rate of LPG, which is varied in a range of 1 to 7 LPM. Air entrainment is controlled for the excess oxygen between 6-7% in the exhaust. Also, the porosity is a constant of 0.5 and the gas pressure keeps constant at 0.4 bar. Through analysis and discussion of this study, the interesting findings can be drawn as follows:  1) the combustion temperature of the PB is 30% higher than that of the CB on average, while the exhaust gas temperature of the PB is 19% lower than that of the CB on average. 2) Based on the efficiency evaluation, the latent energy, the rate of vaporization, and thermal efficiency obtained by the PB are higher than those obtained by the CB with a value of 46%, 56%, and 48.7% respectively. 3) The maximum energy saving of the PB is higher than that of the CB as much as 21%. 4) very low CO emissions are noticed for both types at high loads, while the NOx emission of the PB is 75% lower than that of the CB and the NOx emission of the PB is lower a 20-ppm limit for all load conditions.