Critical unit heating system

The utility model relates to an energy -conserving field of power plant boiler discloses a critical unit heating system, and wherein, this critical unit heating system includes unit A and unit B, and every unit includes oxygen -eliminating device (1, 1'), boiler (2, 2'), steam turbine (3, 3') and steam turbine steam exhaust pipeline (4, 4') respectively, in same unit, the oxygen -eliminating device (1, 1') with the boiler (2, 2') the intercommunication, the boiler (2, 2') with the steam turbine (3, 3') the intercommunication, steam turbine (3, 3') are through steam turbine steam exhaust pipeline (4, 4') and oxygen -eliminating device (1, 1') intercommunication to, unit A's steam turbine steam exhaust pipeline (4) and unit B's steam turbine steam exhaust pipeline (4') intercommunication is in being provided with on the road communicating pipe of two steam turbine steam exhaust pipelines (4, 4') electrical control valve (8). This critical unit heating system can shorten the ignition activation time and the auxi