THERMOECONOMIC ANALYSIS OF THERMAL POWER PLANT

Abstract

Thermoeconomic analysis of a thermal power plant consists of exergy analysis and thermoeconomic evaluation of the power plant. Exergy analysis of a power plant includes exergy analysis of different components of the plant. Exergy analysis can be combined with economic principles to provide useful information. Thermoeconomic evaluation directly shows the cost flow through each individual component as well as through overall system. It also identifies the hidden cost (cost rate associated with exergy destruction) of individual component. Finally the thermoeconomic factor suggests what type of changes should be implemented to a component to optimize the cost flow rate through overall system. In this report a thermal power plant having a generating capacity of 120 MW has been analyzed. The results of exergy analysis show that, there is high rate of exergy loss in boiler and in the high pressure turbine, intermediate pressure turbine and low pressure turbine. From the thermoeconomic evaluation it is noticed that the value of exergoeconomic factor is lower for turbines. Exergoeconomic factor, f, for high, intermediate, and low pressure turbines is 42.98%, 53.00% and 47.15% respectively. This suggests that the overall system can be cost optimized by decreasing the exergy destruction in the turbines. Iterative cost optimization has also been done for the overall system and it is found that the optimum value of pressure of the steam extracted from different turbines i.e. high pressure turbine, intermediate pressure turbine and low pressure turbine should be as suggested in section 7.4. The cost optimized exergetic efficiency of the high, intermediate, and low pressure turbines is 82.41%, 91.41% and 89.32% respectively. By cost optimization the cost flow rate of product is reduced by Rs. 55.80 lacks per year.