Warming system based on back extraction type combined heat and power generation steam extraction back pressure machine

The utility model discloses a machine heating system based on starting of a back extraction type combined heat and power generation steam extraction back pressure machine, which adopts medium-pressure heat supply steam with the pressure of 2.7 MPa and the temperature of 260 DEG C as a machine heating steam source, and a machine heating pipeline is led out from a medium-pressure steam extraction pipeline in the steam extraction back pressure machine and is connected to a main steam inlet pipeline of the steam extraction back pressure machine. And a high-pressure side isolating valve and a medium-pressure side adjusting valve are arranged to adjust the flow of steam entering the steam extraction back pressure machine, and the high-pressure side isolating valve is closed after machine warming is finished. After the technical scheme is adopted, the previous high-parameter warm-up steam with the pressure of 12.8 MPa and the temperature of 525 DEG C is changed, the temperature difference between the warm-up steam a