Studies Of Low-grade Waste Heat For Heating Large Power Plants Used In Centralized

Central heating has become a necessity for urban development, the rapid growth of China’s central heating area, But constrained by environmental pollution, the Country restrictions building or expanding coal-fired boiler. Many areas have heating heat stress phenomena, full use of existing heat and expansion of existing heat source heating area have becoming the direction of development of central heating.Through the study of large-scale thermal power plant circulating cooling water analysis, and by use of ultra-low temperature backwater central heating system, to recover waste heat from power plant condensate to use in urban central heating, expanding the existing heat source heating area, to achieve the plant energy saving. According to the thermodynamic calculation of absorption heat pump derived low temperature heat source inlet temperature variations influence of the heat coefficient of absorption heat pump. Proposed two network central heating system, reduce the heat transfer of absorption heat units and achieve energy cascade utilization. Heating adjustment system adopts two level network of natural gas peak shaving, so that the main source will be working at rated condition of long time.In this paper, make the condensing heat recovery of large power plant as main line, mainly for the following research:(1) Through modeling and energy conservation equations, to analysis the power plant condenser heat, and draw that the steam turbine operation and different parameters of seawater heat exchanger system on the influence of Low-temperature circulating water temperature.(2) By the Ultra-low temperature backwater central heating system to recovery power plant central heating used in condensing heat and the heat exchange station uses absorption heat exchanger unit, the return water temperature will be reduced to25℃, can direct heat exchange with condensate. A Case Study in Huaneng Weihai Power Plant, by calculating the total thermal power plant efficiency, thermoelectric ratio, power consumption of standard coal, Come the effects of recovering condensing heat from power plant and using in central heating on plant.(3) Through analysising the heat transfer characteristics of absorption heat pump, obtains the thermal coefficient of variation when low temperature heat source inlet temperature changes. Through the calculation of power consumption of water pump and heat pipe diameter, to analysis the economic of absorption heat pump heat exchanger unit.(4) Now, Due to the heating methods of heating Users are varieties, propose two network series central heating system, to achieve energy cascade utilization, will reduce the heat transfer of the absorption heat exchanger unit, and expand the heating capacity.(5) Peaking system uses two network natural gas peaking, through simulation examples, and Economic Analysis, get the Optimal peaking factor. Considering fuel gas price fluctuations, Obtains the optimal peaking coefficient variation.The main results of this study have been used in《Weihai special plan for central heating (2013～2020)》, The plan has been reviewed in2013by inside and outside the province of experts, and been approved by Weihai municipal government.