Influence of lignite quality on airborne emissions from power generation in the Russian Far East and in Northern Thailand

Domestic low rank lignites are widely used for power production in the Far East of Russia and in Northern Thailand. The quality of lignites fired in boilers of the power plants in both regions is somewhat variable because of significant fluctuations in the moisture and ash content as well as in the ultimate analysis of fuel. The effect of the fuel quality on airborne emissions (NOx, SOx, CO2 and PM) from the power plant boilers is the focus of this work. The emission concentrations of NOx (as NO2) in flue gas leaving the boiler are predicted based on the fuel analysis, as well as the boiler furnace geometry and operating conditions. The rates of SOx (as SO2) emitted into the atmosphere are estimated taking into account the sulfur content in fuel together with the effect of absorption of sulfur dioxide by fly ash and also efficiency of the FGD units. The emission concentration and rate, as well as the specific emission (per kW h) for the pollutants of interest, were quantified for the selected 55- and 100-MW units (Russian case study) and for the 150- and 300-MW units (Thai case study) fired with lignite of different qualities.