Thermal Economic Analysis About Waste Heat Recovery Of Thermal Power Plant And New Energy Conversion System

In a thermal power unit, exhaust heat of steam turbine is released into the environment, resulting in great loss of the cold sources, thermal pollution and difficult to improve thermal efficiency of the unit; How to reduce the great loss of the cold source, increase the unit’s power capacity and improve the unit’s generating thermal efficiency, becomes a serious problem for the thermal enterprise to be solved.Organic fluid cycle using organic fluids instead of water as working substance is more suitable for recycling of middle and low-grade thermal energy, which could also reduce the loss of the cold source. In this paper, taking the NZK660-24.2/566/566unit as an example, applying the heat pump technology to the thermal system of thermal power unit, physical and mathematical models of the waste heat recovery model1were established; Combining the water steam cycle and the organic fluid cycle, physical and mathematical models of the steam-organic fluid power generation model2and3were established. By thermal economic calculation and analysis on the three models, The results showed that:at designed conditions of THA,75%THA,50%THA, and with the same total heat consumption of the original unit, thermal economy of waste heat recovery model1reduced, thermal economy of power generation model2and model3improved, and that of model2was better than that of model3. The impact of different organic fluids on the thermal economy of power generation model2and3was researched, and the appropriate organic fluids for power generation model2and3were selected. Therefore, selecting the appropriate power generation model and organic fluid could improve the thermal economy of the thermal power unit. In this paper, three models established could provide a reference for improving the thermal economy of the thermal power unit.