Thermodynamic Analysis of Heating Reformation of Large-Scale CHP

A cogeneration operation mode that couples absorption heat pump and screw expander is proposed to realize cascade heating of the return water of the heating network and reduce the loss of cold source and heat exchange process of the unit. Taking a 600 MW unit as an example, a model of a conventional combined heat and power unit and a modified heating unit was built in Ebsilon software to analyze the flexibility and energy consumption of the two operating modes under variable conditions, and plot the rated heating load The exergy diagram below. The results show that after the heating reformation, the maximum heating load of the unit has increased by 106 MW, the maximum heat-to-electricity ratio has increased by 15.4% on average, the minimum power load factor under the rated heating load has been reduced from 50.6% to 44.0%, and the unit's peak shaving capacity has been improved; After the transformation, the total standard coal consumption rate of the unit can be reduced by up to 12.9 g/(kW•h), and the thermal economy is better; when the unit output and heating load are determined, the exhaust efficiency of the steam and water system of the unit after the transformation is higher than under the same conditions Under the rated heating load, the exergy efficiency of the conventional combined heat and power unit increases from 75.9% to 81.1% of the steam-water system after the transformation, and reduces the 13.56 MW cold source loss. © 2022, Science Press. All right reserved.