SOME SOLUTIONS FOR EFFICIENCY IMPROVEMENT OF INDUSTRIAL BOILER SYSTEMS USING SOLID FUELS OR GAS

Abstract

Industrial boiler systems burning solid fuels and gas are widely applied to provide saturated steam for industrial processes. Solid fuels have different compositions and moisture content that affect combustion performance, resulting in high costs for heat production. This paper presents the heat exchange process in a boiler, adopting biomass and Indonesian coal with high moisture content. Thereby, some technical solutions are proposed to improve the efficiency of industrial boiler systems. The results showed that using biomass fuel with a moisture content of 10% for a boiler of 8 bar pressure, the fuel consumption was 200 kg/ton of steam. Fuel consumption increased by 350 kg/ton of steam at 40% moisture content. Fuel consumption rapidly increased at moisture values ​​higher than 40%. Boiler efficiency decreased up to 10% when the moisture difference was 30%. The reasonable moisture content was found to be < 20 % for biomass fuel. For coal, increasing moisture content by 5%, the efficiency decreased by 1.2%, and fuel consumption increased by 10%. Total heat recovery rates were 9.63% and 8.18% for natural gas and liquefied gas fuels, respectively. The obtained results can serve as a good technical reference for employing the existing industrial boiler systems, facilitating the increase of thermal efficiency and reducing the cost of steam production.