Development of a thermally-efficient, durable, and low emission natural gas-fueled electric power generator******

点击翻译按钮获取中文摘要

Etalim Inc. is a Canadian energy-related company that develops small-scale (1-5 kWatt) power generators. These generators convert chemical energy of natural gas to electricity through several thermo-fluid processes, including combustion. Current version of the Etalim burner recovers part of combustion products internal energy prior to exhaust by transferring it to natural gas/air flow. Current Etalim burner mode of operation is premixed combustion, meaning that natural gas and air are fully-mixed before reaction. Unfortunately, this mode of operation does not allow for maximized heat recovery from combustion products due to auto-ignition issue. Specifically, beyond 850 K, the natural gas and air mixture reacts spontaneously before reaching the combustion chamber. This is referred to as auto-ignition and is undesired for premixed combustion systems. In order to address this issue, first, the operation of the Etalim burner will be characterized and optimized using turbulence generating apparatus for premixed mode of operation and for reactants temperatures below 850 K. Then, a swirler will be designed and integrated with the burner, allowing to produce partially-premixed flames. Compared to premixed flames, auto-ignition stabilizes partially-premixed flames and is desired. For this type of flames, the swirler geometrical features, e.g. vane angles, will be modified, aiming to maximize auto-ignition occurrence frequency. This will facilitate development of stable and thermally-efficient Etalim burners. Although the partially-premixed flame configuration may allow for maximized burner thermal-efficiency, it leads to thermoacoustic (heat release rate and pressure) oscillations in the combustion chamber which causes burner mechanical fatigue. Quarter-wave tubes (a damping device), will be designed and integrated with the Etalim burner, aiming to mitigate the thermoacoustic oscillations. Finally, all design parameters related to both fully- and partially- premixed modes of operation will be tuned aiming to minimize combustion pollutants emission. The developed Etalim burner will serve about 290 remote areas in Canada that require stand-alone power generation units. ********