Gas emission characteristics of a novel pulse combustor

The pulse combustor, by virtue of the kinetically controlled reactions, is established as a low gas emissions device. In this paper, a pulse combustor of novel geometry (designated BPCB for blade pulse combustion burner) is described and experimental results for emissions are presented. The BPCB uses aerodynamic valving with the reactants (air and fuel) entering through multiple inlets in the pyramidal shaped combustion zone. As explained in the paper, this results in a compact unit capable of fully resonant high frequency operation. Tests were conducted for both natural gas and natural gas/coal mixtures with fuel energy rate inputs of 4.46 kW (12,518 Btu/hr) for natural gas and an additional 3.14 kW (10,700 Btu/hr) from coal. Gas emission measurements were made using an electrochemical technique and an instrument capable of detecting NO, NO₂, CO, SO₂ and O₂. Particular attention was directed to NO_X and its formation is discussed in some detail in the paper. The experimental results show impressively low levels of all emissions and these are shown to be consistent with the combustion characteristics and novel geometry of the BPCB. For both natural gas and natural gas/coal mixture, NO_X levels were less than 3 ppm except when a lean fuel/air mixture was selected in the coal/gas mixture case. The paper concludes that the BPCB is an excellent candidate for several applications and recommends how more accurate measurements of both emissions and gas temperature should be made