Exergy and thermoeconomics analysis and optimization of Afşin-Elbistan B coal fired power plant

The purpose of this study includes determination of design/operational energy and exergy efficiencies of the power plant and components, assigning the uncertainties and leading factors in the first and second law efficiencies, investigation of thermoeconomic parameter importance and optimum operation conditions by applying second law of thermodynamics to a lignite fired plant. Afşin-Elbistan B power plant was selected as a case study according to some criteria. Range of the coal was investigated with different chemical exergy determination models available in the literature. Calculated chemical exergy of 7088 kJ/kg Afşin-Elbistan lignite found in the largest mine field of Turkey is one of the lowest profile lignite compared to others. Boiler consumes more than 50% of chemical exergy supplied and responsible for more than 70% total exergy destruction. Main uncertainty sources of energy/exergy efficiency are determined to be calorific value computation of the coal, electricity measurement at transformers and mass flow rate of coal respectively. Levelized Cost Of Electricity (LCOE) provided boundary condition for thermoeconomic analysis and figuring out the optimum operational conditions. Two approaches have been compared: one equates electricity generation costs of turbines to LCOE and the other locates costs at each point of the cycle with some assumptions. Keywords : Exergy analysis, Afşin-Elbistan, uncertainty,thermoeconomics