The start-up system with recirculating pump for supercritical unit has such shortcomings as complex structure

high investment

and cavitation in recirculating pump.Therefore

a pressed steam-water injector is proposed to replace the recirculating pump. Numerical computation of output pressure based on the direct contact condensation model demonstrates that the new start-up system with pressed steam-water injector possesses not only the same functions of the original system

but also the advantages of simple structure

low investment

higher reliability

and cavitation-free.In the pressed steam-water injector

supersonic steam flow drives sub-cooled water and condenses in it

the condensation changes the mixture temperature to form a shock wave for improving water discharge pressure.The new start-up system takes high-speed steam flow formed by drainage vaporization as its source power.