Why do we need to extract steam from the steam turbine to increase the height?

【Question】: If there is no high or low, is it OK?

[Answer]: OK, but the feed water temperature entering the boiler is very low and the thermal efficiency is extremely poor.

【Question】: Where does the heat source come from?

[Answer]: Steam turbine extraction.

[Question]: Why do you need to extract steam from the steam turbine to increase the height?

【answer】:After heating with feed water back heating, on the one hand, a part of steam is extracted from the middle part of the steam turbine, and heating the feed water increases the boiler feed water temperature.This will prevent the extraction of steam from condensing and expelling heat in the condenser, reducing the loss of cold sourceq2。anotherIn terms of the water supply temperature is increased and the heat absorption of water supply in the boiler is reduced.q1。

Therefore, when the initial and final parameters of steam are the same, the thermal efficiency of using feed water regeneration cycle is higher than that of the Rankine cycle.

【Question】: Why is the four draws very special?

[Answer]: Under the rated working conditions, the four-shot pressure is 0.78MPa. It is a deaerator steam source, a small steam source, and a de-auxiliary steam source. at the same timeHigh pressure shaft sealing steam leakage,highThe pressure-regulating door leakage steam also flows into four pumps.

It is precisely because of its special nature that the four-drawer does not participate in the activity test of the steam-drawer counterstop door.