8. Heater Drain and Vent (P&IDs)
8.0. Heater Drain and Vent System
In shell and tube type heaters, after transferring the heat to condensate (LPHs) or FW (HPHs), extraction steam condenses to water, which needs to be returned to the system at the condensate/deaerator through a heater drain and vent system.
8.1. Objective and Function of the System
This system includes the following major functions:
• To condense the extraction steam and to return to the system.
• Heater draining is necessary to prevent induction of water to the TG by draining the water accumulated to the preceding heater, deaerator, and/or condenser.
• By proper selection of drain control valves, possible water hammering between FW heater and condenser is prevented.
• Maintenance of ...