Energy and exergy analyses of a subcritical pulverised coal-fired boiler based on the effects of slagging and fouling

Abstract

Globally coal-fired power plants are still predominantly utilised for production of electrical energy. The efficiency of a coal-fired power plant is greatly influenced by the performance of the boiler. In turn, the boiler performance is affected by the coal type, combustion characteristics, and the heat transfer from the flue gas side to water-steam side. In the boiler the heat transfer is impeded by the accumulation of ash deposits, known as slagging and fouling, on the heat transfer surfaces. In this paper the effects of slagging and fouling on the boiler performance are investigated by means of energy and exergy analyses. A boiler simulation model, representative of the combustion and heat transfer characteristics, is used to perform the analyses. From the results it is seen that slagging has the most significant effect, while fouling has a less significant influence, on the boiler energy and exergy efficiency