Plasma Ignition and Combustion Stabilization (PICS) Technology for Pulverized Coal Fired Boilers
PICS was developed by LY Power with independent intellectual property right. By March 2020, LY Power has applied this technology on 862 units including 31 overseas units in South Korea, Russia, Southeast Asia, Europe, Africa, etc., with total installed capacity over 370GW.
Plasma generator ionizes the air, producing plasma with high temperature ranging from 4,000 to 10,000 degree K. When the pulverized-coal is directed to go through the high temperature plasma in the plasma burner, a series of physical and chemical reactions will occur instantly including fission, separating volatile, rebuilding volatile and burning violently. The coal is thus ignited inside the burner and then goes into the furnace, realizing boiler ignition and stabilized combustion without the use of traditional oil guns.
1. Pulverized coal can be directly ignited by plasma arc to largely save or even eliminate fuel oil consumption during boiler ignition and combustion stabilization after implementation of PICS.
2. Boiler startup can be controlled smoothly matching the boiler temp & pressure ramp-up curves. Meet all requirements for unit ignition and combustion stabilizing during low-load operation.
3. Even if the unit can not be synchronized for long time (several hours) due to turbine or other equipment problems, SOC KPI will not be significantly impacted.
Ensure continuous and reliable service of ESP during boiler cold start-up.
4. Suitable to both T-fired and wall fired boilers. Suitable to both newly-built and retrofit boilers.
5. Less maintenance compared with conventional fuel oil igniting system. Avoid possible accidents and casualties caused by fuel oil system.
6. Very short Investment Recovery Cycle.
PICS mainly comprises plasma generator, plasma burner, power supply system, pulverized coal air heating system for cold boiler startup, carrier medium (air) system, cooling water system, control system and monitoring system
1.The device to produce and control the plasma arc.
2.The output power is continuously adjustable from 50KW to 200KW.
3.Suitable for bituminous coal and lignite.
Plasma burner is a pulverized coal burner equipped with a plasma generator that can be used for boiler ignition and combustion stabilization in low load operation. The output of plasma burner and air velocity at the burner nozzle shall be designed same as the original burner. PICS will not change the combustion organization and state within the furnace. In addition, the muti-stage cylinder structure applied on the plasma burner can largely enhance its ignition performance.
Cooling Water System
Cooling water system consists of boosting pump, dedicated water tank, heat exchanger, etc, providing cold water to cool the electrodes (cathode & anode) and magnetic coil of plasma generator. The cooling water should be demineralized water with temperature below 40 degree Celsius.
Carrier Medium (Air) System
The carrier medium (air) is the medium of plasma arc. After the arc being generated, the carrier medium (air) with a certain velocity can blow it out of the anode to form a stable plasma. It should be dry and clean air with fixed pressure taken either from air compressor or from centrifugal fan.
PICS can be controlled by Distributed Control System (DCS) and integrated into the Furnace Safeguard Supervisory System (FSSS) of the boiler. All actions like arc generation, arc switching off, power adjustment, etc can be operated locally & remotely. Further, mature logic design which has been demonstrated on hundreds of projects shall be implemented to secure the operation safety.
Power Supply System
Power supply system consists of dry-type transformer, low-voltage power distribution cabinet, isolation transformer and rectifier cabinet. Rectifier cabinet is the core component of the power supply system. LY Power have developed the LYKG series of rectifier cabinets with independent intellectual property for PICS.
Pulverized Coal Air Heating System for Cold Boiler Startup
The system provides hot air to the existing pulverizing system during boiler cold startup without fuel oil firing support. The hot air can be obtained either from the cold air heater (cold air steam air heater or cold air oil heater) which shall be added to the existing pulverizing system or from the adjacent boilers.
Bituminous Coal and Low-moisture Lignite
For the boiler burning bituminous coal and low-moisture lignite, the suitable type of plasma generator is DLZ-200 (70~105kW). After PICS application, these boilers can realize oil free operation. Especially for newly built units, tremendous investment can be saved after eliminating the entire fuel oil system, so is a large quantity of fuel oil during period of unit commissioning
Aiming at high-moisture lignite, LY Power PICS applies bias concentration plasma burner, DLZ-300 generator and modular large capacity power supply. Lignite with 35%~40% moisture can be effectively ignited by PICS.
Low Quality Bituminous and Lean Coal
Common PICS can not meet the requirements of igniting low quality bituminous and lean coal. In view of this, LY Power developed PICS+O2 technology. Industrial oxygen is supplied in appropriate position of burner to enhance combustion intensity of pulverized coal, raise flame temperature and reduce ignition distance. PICS plus O2 can steadily ignite these low quality coal. Replacing fuel oil with PICS+O2, the operating cost is only about 10%~20% of the original oil system.