Plasma-Aided Coal Ignition and Combustion: Modeling and Full-Scale Trials

Abstract

Applications of the modern plasma technology for solid fuel ignition and combustion are presented. This technology provides a more efficient and environmentally friendly low-rank coal incineration. To implement this technology at coal-fired thermal power plants, plasma-fuel systems (PFSs) were developed. The PFS is a pulverized coal burner equipped with an arc plasma generator producing a high temperature air stream of 4000 °C-6000 °C. The PFS technology is plasma thermo-chemical preparation of coal for burning. It includes plasma heating of air-coal mixture up to the temperatures, when coal volatiles are released and partial gasification of char carbon occurs. To show the advantages of plasma-aided coal combustion as compared with the conventional one, the numerical simulation of the process was carried out. The numerical modeling was performed for the low-rank bituminous coal of 40% ash content incinerated at a boiler of 420-t/h steam productivity. Full-scale trials of the plasma-aided combustion confirmed the possibility of high-ash coal ignition in the cold furnace without heating of primary air.