Thermodynamic and exergo-economic analyses of a supercritical coal-fired boiler for the sustainable and cost-effective selection of coal

Abstract

In this article, thermodynamic and exergo-economic analyses of an 800 MW supercritical coal-fired boiler have been carried out to find the energetic and exergetic efficiencies of the boiler and to identify the exergo-economical operation of the boiler under different loads with various grades of coal. Exergo-economic parameters for all the heat transfer components inside the boiler have been evaluated and analysed. Exergo-ecomonomic cost formation of steam generation throughout the water-steam circuit of the boiler has been analysed. Based on exergo-economics, a break-even study has been carried out to determine the limiting cost of various grades of coal as boiler-fuel against the use of design coal (used for boiler design) for cost-effective steam generation. A common factor f 1 (involving exergy, exergo-economic cost efficiency, and boiler load) has been plotted for counter factor f 2 (boiler emission level), which resulted in a Pareto front that could assist in deciding for the sustainable and cost-effective selection of coal out of various grades of coal. A weighted sum method has been applied for optimisation.