| Extraction steam heating and low vacuum heating are the mainly methods of current cogeneration district heating. The new circulating water quality improvement technology base on the absorption heat pump is endowed with potentials. The research is shown that decrease of cold source loss is the most effective method to improve the efficiency of turboset.25MW extraction steam turbine units of Lindian is taken as examples to put forward the heat power and cool cogeneration technology n this paper. Firstly, Matlab is used to stimulate the circulating process of lithium bromide absorption heat pump to analyze the influence rule of parameters as the temperature of driving heat source on the thermal process. Secondly, theoretical calculation models of absorption heat pump and turboset are established. The performance indexes of the extraction steam heating unit and circulating water absorption heat pump heating unit in rated condition and maximum operation cognition are contrasted and analyzed. In the rated conditions of scheme â…¡, When the coefficient of heat supply of the heat pump unit amount to 1.65, the thermal efficiency of circulating water absorption heat pump heating unit reach up to 77.7% and the heating load amount to 83.47MW, which are 22.43 percentage and 31.3MW higher than those of extraction steam heating unit respectively. The heating capacity is improved by 60%. The heating load amounted to 104.41MW under the condition of recovering all circulating water low-temperature exhaust heat. Finally, a steam exhaust comprehensive utilization system is put 0.25g/kWh forward to the steam exhaust to determine power by heating (cooling) and improve the utilization of steam exhaust of turbine 0.46 g/kWh.The research is shown that the quality improvement and utilization of waste heat of low grade circulating water by absorption heat pump could reduce the cold source loss of the unit and improve the thermal efficiency and heating load of the unit. |
