Energy, Exergy and Cost of Exergy Destruction for Coal-Fired Boiler in the Beverage Industry

This paper performs an energy and exergy analysis based on data obtained from selected boilers in the beverage industry. The boiler output is 16 tons/h with a pressure of 8 bar, and the steam output is saturated vapor. A boiler is designed for coal - fired fuel (sub-bituminous coal) with an economizer (heat exchanger) for recovered waste heat. This study aims to illustrate the energy, exergy, energy efficiency and exergy efficiency of the boiler, to identify the energy and exergy effect, including the exergy destruction costs of various loads. The data observation and recording have been made under the Thailand climatic conditions during the year 2023. The results indicated that the maximum energy and exergy efficiencies were approximately 87.98% and 27.45%, respectively, at 100% boiler load, while the minimum energy and exergy efficiencies were approximately 58.82% and 18.16%, respectively, at 25% boiler load. The highest exergy destruction, about 24,447,952 kJ/h, was also observed at 100% boiler load. The results demonstrated that as the boiler load increased, both energy and exergy efficiencies increased accordingly. The cost analysis revealed that the maximum cost of per hour was estimated at 4,323 ฿ for 100% boiler load. The analysis results confirmed that the boiler load is a major parameter influencing the overall performance of the boiler.