To improve the flexible heating capacity of large-scale coal-fired heat and power generation system for absorbing the intermittent renewable energy

a 350 MW coal-fired condensing unit with medium-pressure cylinder extraction steam for heating was selected as the research object in this paper

and then the flexibility of large-scale coal-fired CHP system was studied. Firstly

the simulation model of this condensing unit was built through the Ebsilon software. Next

six heating modes such as middle extraction steam

electric boiler coupling with extraction steam

electric heat pump

electric heat pump coupling with extraction steam

absorption heat pump as well as cutting out low-pressure cylinder

were evaluated respectively from the aspects of thermoelectric load adjustable range and energy consumption characteristics. The results show that

compared with middle extraction steam heating

the electric heat pump heating

electric heat pump coupling with extraction steam heating

absorption heat pump heating and cutting out low-pressure cylinder heating increase the maximum heating power from 336 MW to 631 MW

563 MW

453 MW and 545 MW

respectively. The maximum heat-electricity ratio increases from 1.39 to 7.97

6.47

1.87 and 2.92

and the average standard coal consumption rate in the maximum heating power heating mode reduces from 185 g/(kW·h) to 137

147

152 and 140 g/(kW·h)

respectively. The case study shows that the electric heat pump heating mode can effectively reduce the average standard coal consumption rate of the system under the background of absorbing higher-proportion renewable energy.