The local ignition control system is designed by Eastern Boiler Control Co., Ltd specifically for INDIAN SAGARDIGHI 2×300MW power plant.
The boiler designed by Dong Fang Boiler Group Co., Ltd specifically for INDIAN SAGARDIGHI 2×300MW power plant includes:
a. Four (4) Elevations of tangential fired oil compartments, which one include: one (1) light oil gun and one (1) heavy oil gun.
b. Four (4) Elevations of tangential fired coal compartments.
Each oil burner is equipped with a Class 3 Special igniter, as defined by NFPA. This is a high energy spark type igniter for direct ignition of the atomized oil burner during oil burner light off.
First, the light oil gun will be lit off by igniter with the commands from operator, then the heavy oil gun will be lit off by the light oil gun with the commands from operator.
The igniter is also brought into service when the oil atomizer is shutdown and purged (scavenged) to remove oil from the atomizer, the oil being lit by the igniter as it is ejected from the atomizer by the purge (scavenged) steam. These typical functions will be completed in FSSS (or BMS) logic.
In remote operation mode, the local ignition control system, accepted the command from FSSS (or BMS) which is a part of DCS, send drive signals to local devices of oil burner.
In local operation mode, the local ignition control system, accepted the commands from operator, send drive signals to local devices of oil burner.
2 System function
The local ignition control system consists of sixteen (16) local control cabinets and sixteen sets of local devices for oil burner.
2.1 Local devices of a oil burner For each oil burner, includes:
◆ Heavy oil gun insert/retract actuator drove by instrument air
With a single solenoid valve and insert/retracted limit switches (DPDT) ◆ Light oil gun insert/retract actuator drove by instrument air
With a single solenoid valve and insert/retracted limit switches (DPDT) ◆ Igniter insert/retract actuator drove by instrument air
With a dual solenoid valve and insert/retracted limit switches (DPDT) ◆ High Energy Igniter (HEI)
◆ Light oil shut-off valve
With a dual solid valve & pneumatic actuator & opened/closed limit switches (DPDT) ◆ Light oil purge valve
(DPDT)
◆ Light oil atomization valve
With a dual solid valve & pneumatic actuator & opened/closed limit switches (DPDT) ◆ Heavy oil shut-off valve
With a dual solid valve & pneumatic actuator & opened/closed limit switches (DPDT) ◆ Heavy oil purge valve
With a single solenoid valve & pneumatic actuator & opened/closed limit switches (DPDT)
◆ Heavy oil atomization valve
With a dual solid valve & pneumatic actuator & opened/closed limit switches (DPDT)
2.2 The signals from the ignition control system to DCS:
◆ Light oil valve opened ◆ Light oil valve closed
◆ Light oil atomization valve opened ◆ Light oil atomization valve closed ◆ Light oil purge valve opened ◆ Light oil purge valve closed ◆ Heavy oil valve opened ◆ Heavy oil valve closed
◆ Heavy oil atomization valve opened ◆ Heavy oil atomization valve closed ◆ Heavy oil purge valve opened ◆ Heavy oil purge valve closed ◆ Igniter insert
◆ Igniter retracted ◆ Light Oil gun insert ◆ Light Oil gun retracted ◆ Heavy Oil gun insert ◆ Heavy Oil gun retracted ◆ Local operation requirement ◆ HEI sparking
2.3 The signals from DCS to the ignition control system:
◆ Local operation permission
◆ Open command to Light oil valve ◆ Close command to Light oil valve
◆ Open command to Light oil atomization valve ◆ Close command to Light oil atomization valve ◆ Open command Light oil purge valve
◆ Close command to Light oil purge valve ◆ Open command Heavy oil valve opened ◆ Close command to Heavy oil valve closed
◆ Open command Heavy oil atomization valve opened ◆ Close command to Heavy oil atomization valve closed
◆ Open command Heavy oil purge valve opened ◆ Close command to Heavy oil purge valve closed ◆ Insert/ retract command to Igniter
◆ Insert/ retract command to Light Oil gun ◆ Insert/ retract command to Heavy Oil gun ◆ Energize HEI transformer
◆ Flame on
3.2 Igniter and oil gun insert/retract actuator
The heavy oil gun insert/retract actuator is controlled by a solenoid 5/2 valve. Once operated the “insert” valve will remain in its operated position after the pulse has been removed and until the retract solenoid is operated.
The light oil gun insert/retract actuator is controlled by a solenoid 5/2 valve. Once operated the “insert” valve will remain in its operated position after the pulse has been removed and until the retract solenoid is operated.
The HEI igniter insert/retract mechanism is controlled by a single acting solenoid 3/2 valve which is energized to insert the igniter pod.
In the oil corner start or stop sequence, neither heavy oil gun or light oil gun need to be insertd or retracted. When advancing command which will be sent to the solenoid 5/2 valve, the oil gun is insertd via the insert/retract actuator drove solenoid 5/2 valve, the oil gun is retracted via the insert/retract mechanism drove by instrument air.
Before energizing the HEI transformer, the igniter pod must to be insertd. When advancing command which will be sent to a solenoid 3/2 valve, the igniter is insertd via the insert/retract actuator drove by instrument air. When the advancing command is missing, the igniter will be retracted to the original position.
3.3 High energy igniter (HEI)
The HEI is used to ignite oil gun in power plant station. It includes:
● HEI transformer ● Igniter pod
● Special cable assembly between HEI transformer and igniter pod (about six 6 meter long0
The igniter pod moves with the igniter insert/retract actuator. Its length depends on the light oil gun requirements. Before sparking in the start or stop sequence, the igniter pod need inserted in the atomizing area of light oil gun. After the sparking, the igniter pod must be retracted from the flame area as a protection against heat overload.
HEI transformer accepts the energizing signal. A high tension capacitor in the HEI transformer is charged up with energy and then released via a special cable assembly to the igniter pod. The resultant arc discharge converts the energy into heat which ignites the fuel.
3.4 Oil corner shut-off valve. Atomization valve & Purge valve
Both light oil shut-off valve and heavy oil shut-off valve drove by instrument air, which we supplied, is controlled by solenoid 5/2 valve. When opening command is sent to the solenoid valve, the valve is opened via the pneumatic actuator. When closing command is sent to the solenoid valve, the valve is closed via the pneumatic actuator.
Both light oil atomization valve and heavy oil atomization valve drove by instrument air, which we supplied, is controlled by solenoid 5/2 valve. When opening command is sent to the solenoid valve, the valve is opened via the pneumatic actuator. When closing command is sent to the solenoid valve, the valve is closed via the pneumatic actuator.
Both the light oil purge valve and heavy oil purge valve is controlled by single solenoid coil (solenoid 3/2 valve). When opening command is sent to the solenoid valve, the purge valve is opened via the pneumatic actuator. When missing the opening command, it is closed automatically.
Main performance parameter of heavy oil shut-off valve or light oil shut-off valve as below:
● Control voltage:240VAC 50Hz
● Instrument air pressure:0.4~0.8 MPa ● Medium temperature: ＜250℃
● Atomization/purge steam temperature: 220~250℃ ● Medium pressure: ＜3.2MPa
Main performance parameter of heavy oil atomization valve or light oil purge valve as below:
● Control voltage:240VAC 50Hz
● Instrument air pressure:0.4~0.8 MPa ● Medium temperature: ＜250℃
● Atomization/purge steam temperature: 220~250℃ ● Medium pressure: 0.78~1.27 MPa
Main performance parameter of heavy oil purge valve or light oil purge valve as below:
● Control voltage:240VAC 50Hz
● Instrument air pressure:0.4~0.8 MPa ● Medium temperature: ＜250℃
● Atomization/purge steam temperature: 220~250℃ ● Medium pressure: 0.78~1.27 MPa