During the startup and operation of the main condenser, a certain amount of air inevitably enters the condenser. This air cannot be condensed into liquid and will accumulate over time. Excessive accumulation can degrade vacuum levels, impairing normal condenser operation. Therefore, it must be continuously extracted to maintain proper functioning, necessitating a vacuum extraction system.

Condenser Vacuum Extraction Procedure:

Open the condenser air vent valve.

Circulate cooling water through the condenser.

Ensure the condensate system is operating normally.

Verify the water level in the ejector tank is within range.

Start the ejector pump and confirm normal current/pressure readings.

Open the air extraction valve of the steam ejector.

Supply sealing steam to the turbine shaft glands.

Monitor the gradual rise in condenser vacuum.

Key Technical Notes:

Vacuum Criticality: Maintains turbine backpressure (typically 5~15 kPa(a) in thermal plants)

Air Ingress Sources: Shaft seals, flanges, or dissolved gases in feedwater

Ejector System: Often uses steam-jet ejectors or liquid-ring vacuum pumps

Performance Metric: Air removal rate measured in kg/h (per HEI Standards)

Industrial Standards Compliance:

ASME PTC 12.2: Steam Surface Condenser Performance Testing

HEI Standards: For power plant condenser design

GB/T 3626: Chinese code for power station condensers