Cold end loss is the largest loss of thermodynamic system in thermal power plants. If the exhaust waste heat of steam turbine can be fully recycled for heating

it will significantly improve the ability of heating and efficiency of energy utilization for the power plant

and bring huge benefits such as energy-saving

environmental protection as well as other social benefits. On the basis of the double-backpressure heating energy saving reformation in supercritical 600 MW direct air cooling unit of Chaoyang Yanshanhu Power Generation Company

the possible problems and retrofit schemes of systems and steam equipments were discussed

like in the final stage blade of the furbine

the exhaust steam pipe system

the condensate water system

the vacuum pumping system

the circulating water system

the water level balance system of hot water well of exhaust unit

the condensate cooling system

and the secondary heating system of circulating water in hot networks. Moreover

the control measures related to the double-backpressure heating system were proposed

like the back pressure limit

back pressure control

air cooling island antifreeze

start-up and stop of double-backpressure operation

heat exchanger leakage treatment

setting up of condensate cooling system

and water temperature control at the heating network outlet. Finally

the retrofit effect was discussed from the aspects of energy saving and emission reduction effect

operation safety and flexible peak-shaving. The technology this article proposed provides a new way for thermal power plant flexibility reformation.