Effects of Condenser Pressure Variation & Cooling Tower Performance Study of Coal Fired Thermal Power Plant

Abstract

In India thermal power plants contributes 58% of electricity generation. Out of total power produced certain energy is consumed by auxiliary systems used in power plants. It is necessary to conserve the energy usage by auxiliaries of plant by implementing energy conservation strategies. Energy audit is one of tool to know health of plant equipments. Energy audit ought to cowl evaluation of the performance of major equipments, determine the manageable losses and recommend that parameters for improvement. In present work energy audit and exergy analysis of six cooling tower and nine circulating cooling water pumps was carried out. Based on that assessment it is evident that cooling tower number 4 and 5 have poor effectiveness 57.14% and 59.32% respectively. In natural draft cooling tower insufficient heat transfer takes place due to non-uniform distribution of water which reflects the lower effectiveness of cooling tower. Overall efficiency of circulating cooling water pump is between 51.9% to 76% for all pumps. Specific power consumption is 0.10 to 0.17 kW/m3/hr for all pumps is higher than design value. Higher inlet temperature of cooling water at condenser leads to poor vacuum and higher heat rate of power plant. Total 48.18 crore kcal heat rate increases annually which required approximately 137 tonnes of extra bituminous. Heat rate of all seven units, as per direct method is greater than design heat rate. Condenser effectiveness is in range of 50.67% to 73.68% . Condenser pressure increases with increament in cooling water temperature. So it is desirable to operate cooling water pumps at optimum flow rate to control cooling water temperature. Exergy analysis has been carried out for cooling tower, circulating cooling water pumps and condenser in which exergy efficiency of cooling tower is between 30.98 to 46.79%, In circulating cooling water pump exergy efficiency is between 56.53 to 68.49% and in condenser it is between 27.72 to 56.55% .