Control Modes of Gas Collector Main

1,Interlock Protection for Blower

The blower is interlocked with multiple parameters including the temperature of three-phase stator coils of the motor, motor bearing temperature, blower bearing bush temperature, shaft displacement, and oil supply pressure of the oil station. The rotating speed can be interlocked with gas flow rate, suction pressure before the blower and gas collector main pressure to realize automatic speed regulation.

Meanwhile, the high-pressure ammonia water flow signal is collected to boost the blower speed for coal charging compensation, and the reversing signal is collected for reversing compensation speed increase. Operators can also disable the compensation function or adjust the compensation amplitude according to the actual gas volume.

Since changes in blower rotating speed exert a remarkably obvious impact on gas collector main pressure, the regulation sensitivity of DCS shall be reduced. Based on actual operating conditions of the plant, the blower rotating speed is generally controlled manually during production, with coal charging compensation, reversing compensation and over-limit compensation for suction pressure before the blower enabled.

2.Automatic Control of Main Recirculation Actuator

The automatic control of the main recirculation actuator can be interlocked with either the average pressure of gas collector mains or the suction pressure in front of the primary cooler. Normally, the blower rotating speed is adjusted to reserve a certain regulating margin for the opening of the main recirculation valve. Benefiting from high regulation precision and fast response of the actuator, it can completely replace blower speed regulation when the gas flow rate has no drastic fluctuations.

During non-coal-charging periods, the fluctuation of gas collector main pressure is mild, and the pressure of two gas collector mains basically rises or falls synchronously. Under such circumstances, interlocking with the average pressure of the two gas collector mains is adopted to achieve timely and accurate regulation. This also reduces frequent actions of electric actuators on gas collector mains and extends their service life.

During coal charging, the blower speed will increase. Occasionally, the pressure of the gas collector main on the coal charging side rises to a positive deviation while the pressure of the non-charging side drops to a negative deviation. Through program configuration, the interlock target of the main recirculation actuator will automatically switch to the suction pressure before the primary cooler during coal charging, so as to prevent excessive suction pressure ahead of the primary cooler.

3.Automatic Control of Gas Collector Main Actuators

The automatic control of each gas collector main actuator is interlocked with the pressure of its corresponding gas collector main. Coal charging compensation and door closing compensation are additionally configured. Together with blower coal charging compensation and time-segment pressure control of high-pressure ammonia water, these control strategies are collectively referred to as "fuzzy control".