Operation Research Of New Co-generation Heating System Based On Waste Heat Utilization Of Exhausted Steam

Utilizing the waste heat of exhausted steam in power plant as a new type of heat source is a key direction to achieve both energy-saving and clean urban heating.In order to recycle all the exhausted steam waste heat of multiple units at the same time,the authors' research group proposed a new cascade heating system with multi-heat source and applied it in several power plants in China.This paper focuses on the energy efficiency decreasing and operation safety of air-cooling condenser effecting problems and formulated the operation strategy of the new system,the main study contents include:Taking two sets of 300 MW direct air cooling turbine units as the example,the authors' research group proposed a new cascade heating system with combination and co-complementarity of reducing the temperature of return water,increasing backpressure of turbines and setting up the absorption heat pump(AHP)in power plant,then established the calculation model of system heating characteristics.This paper analyzed the change regulation of main parameters of heat network and turbine unit in full operating conditions.It is found that when the exhausted steam can't be completely recycled for supplying district heating,the surplus heat needs to release in air-cooled condenser,in that case the energy efficiency of system and safety of air-cooling condenser would be affected.This paper introduced the “equivalent electricity of heating” as the evaluation method of comprehensive energy efficiency of the new co-generation heating system and analyzed the key influence parameters of “equivalent electricity of heating”.This paper improved the integration of heating system and put forward the comprehensive optimization ideas of operational parameters to reduce the “equivalent electricity of heating”.On this basis this paper proposed the optimization method for combined operation of multiple units.Taking the waste heat recovery project of Datong Yungang power plant as the object of this study to carry out targeted engineering practice research.The results of theoretical research of this paper was used to guide the operation strategy formulating of the new system.Besides,the energy efficiency,technical and economic performance of the new system was demonstrated.The results indicate that the new system presented in this paper had significant advantages in application value.