The function of exhaust during heater operation is to release the pressure on the steam side of the heater. When the heater is running, it will generate a large amount of gas. In order to balance the air pressure, it is necessary to exhaust the heater in a timely manner.

During the operation of the heater, in order to timely exhaust non condensing gases without causing refrigerant loss, enhance heat transfer and prevent corrosion of thermal equipment, exhaust devices and pipelines are installed on the steam and water sides of the heater. The steam side of the heater is equipped with starting exhaust and running exhaust. Startup exhaust refers to the exhaust during unit startup and hydraulic test. Operation exhaust refers to the discharge of non condensable gases from the heater during normal operation of the unit. During the operation of the exhaust system heater of the 1600MW unit, in order to timely exhaust non condensable gases without causing refrigerant loss, enhance heat transfer, and prevent thermal equipment corrosion, exhaust devices and exhaust pipes are installed on the steam and water sides of the heater. The steam side of the heater is equipped with starting exhaust and running exhaust. Startup exhaust refers to the exhaust during unit startup and hydraulic test. Operation exhaust refers to the discharge of non condensable gases from the heater during normal operation of the unit. Exhaust system of 600MW unit

The start-up exhaust of the high-pressure heater is discharged into the atmosphere through three exhaust pipes and two isolation valves. The exhaust gas during operation is led out from each heater and collected into a main pipe through two isolation valves before entering the deaerator. It is then discharged into the atmosphere with the gas in the deaerator. In the exhaust system of the low-pressure heater, there is an isolation valve and a throttling orifice plate on the starting exhaust pipeline of the low-pressure heater, and there is an isolation valve and a throttling orifice plate on each of the two operating exhaust pipelines. Due to the vacuum state on the steam side of the low-pressure heater during start-up, the start-up exhaust and operational exhaust of the low-pressure heater are combined and discharged into condenser B. The start-up exhaust and operational exhaust of the low-pressure heater are combined and discharged into the condenser. The exhaust from the low-pressure heater is directly discharged into the condenser. A throttle orifice is set on the exhaust pipe to limit the Engine displacement and prevent the steam with excessive Engine displacement from being taken out of the heater. The exhaust system of the 1300MW unit is the exhaust system of the 300MW unit. The starting exhaust of each high-pressure heater only has one exhaust pipe, and the running exhaust is collected through a throttle orifice and an isolation valve before being discharged into the deaerator. The start-up exhaust and operational exhaust of low-pressure heaters H5, H6, and H7 converge and enter the condenser, while the exhaust of H8 directly enters the condenser. Due to the different working pressures of each heater, the following measures were taken during the design and installation to avoid the circulation circuit formed by the exhaust systems of adjacent heaters, which would affect the exhaust of lower pressure heaters:

1. The interface between the lower pressure heater exhaust and the main pipe should be downstream of the higher pressure heater exhaust interface; The diameter of the exhaust main pipe should be large enough;

2. The exhaust of the deaerator directly enters the atmosphere;

3. All heaters (including deaerators) are equipped with safety valves to prevent overpressure;

4. All heaters are equipped with manually operated air exhaust valves on the water side, so that the air in the water chamber can be discharged when the heater is filled with water;

5. There is also a nitrogen filling pipeline on the exhaust pipe of the high-pressure heater steam side startup, which is used for anti-corrosion protection of the heater during shutdown;

6. All heaters also have chemical cleaning pipelines for