Water supply heating device and water supply heating method by utilizing bypass heat of steam turbine

The invention discloses a water supply heating device and a water supply heating method by utilizing bypass heat of a steam turbine. At present, in the initial stage of starting, the temperature of feed water mainly depends on heating of a deaerator, a steam source is generally auxiliary steam, the steam amount of the auxiliary steam is limited, and therefore the temperature of the feed water is difficult to increase. The system comprises a main steam inlet pipeline, the main steam inlet pipeline is connected with a high-pressure cylinder (4) and a reheater pipeline through a high-pressure main steam valve (18) and a high-pressure bypass adjusting valve (1), the high-pressure cylinder is connected with the reheater pipeline through a high-emission check valve (2), and a reheater inlet pipeline is connected with a medium-pressure cylinder (5) through a medium-pressure main steam valve (19). The medium-pressure cylinder is respectively connected with a low-pressure cylinder A (6) and a low-pressure cylinder B (