Plasma Ignition and Combustion Stabilization (PICS) Technology for Pulverized Coal Fired Boilers
Plasma generator ionizes the air, producing plasma with high temperature ranging from 4,000 to 10,000 degree K. In the plasma burner the pulverized-coal is directed to go through high temperature plasma initiating a series physical and chemical reactions instantly including fission, separating volatile, rebuilding volatile and burning violently. The coal is thus ignited inside the burner and goes into the furnace eliminating the use of oil guns for coal firing. The ignition and stabilized combustion are thus implemented.
Product Features
1.Pulverized coal can be directly ignited by plasma arc to largely save or even eliminate fuel oil consumption during ignition and combustion stabilization after implementation of PICS.
2.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.Long time (several hours) can not be synchronized, due to the turbine or other equipment problems, will not significantly impact the SOC KPI.
4.Ensure continuous and reliable service of ESP during cold start-up.
5.Suitable to both T-firing and wall firing boilers. Suitable to both newly-built and retrofit boilers.
6.Less maintenance compared with conventional fuel oil igniting system. Avoid accidents and casualties caused by fuel oil system.
7.Very short Investment Recovery Cycle.
System Composition
PICS mainly comprises plasma generator, plasma burner, power supply system, pulverized coal air heating system for cold boiler startup, medium air system, cooling water system, control system and monitoring system.
Plasma Generator
1. The device to produce and control the plasma arc.
2. The output power is adjustable from 50kw to 200kw. 3 Most suitable for bituminous coal and lignite.
3. Most suitable for bituminous coal and lignite.
Plasma Burner
The pulverized coal-fired burner equipped with a plasma generator which is used for ignition and combustion stabi- lization in low load operation. Output of plasma burner and air velocity of the burner nozzle shall be designed as origin, PICS will not change combustion state inside the furnace. In addition, the muti-barrel structure is applied on plasma burner for promotion of the ignition performance.
Cooling Water System
The system equipped with boosting pumps, separate water tank, heat exchanger, etc, provides cold water for cooling electrodes (cathode, anode) and coil of plasma generator. The cooling water is usually taken from demineralized water with temperature below 40 Celsius degree.
Air Medium System
This system provides plasma medium (air) for the plasmatrons. Dry and clean air with fixed pressure from either compressor or centrifugal fan is used as the medium by the plasma generator.
Control System
PICS can be controlled by Distributed Control System(DCS) and integrated into Furnace Safe- tyguard Supervisory System(FSSS). All actions like arc generation, arc switching off, power adjustment, etc can be operated locally & remotely. Further, mature logic design which has been demonstrated by hundreds of projects shall be implemented to secure the safety.
Power Supply System
Power supply system generally consists of dry-type transformer, low-voltage power distribution cabi- net, isolation transformer, rectifier cabinet. Rectifier cabinet is the core component of power supply system. LYKG series of rectifier cabinets have been specially devel- oped by LY Power with independent intellectual property.
Pulverized Coal Air Heating System for Cold Boiler Startup
The system provides hot air for the existing coal pulverizing system during the period of boiler cold startup without oil firing support. The hot air can be obtained from the cold air heater (air heater with steam or air heater with oil combustor) which is added to the existing coal pulverizing system or from the adjacent boilers.
Coal Adaptability
Bituminous Coal and Low-moisture Lignite
For the boiler burning bituminous coal and low-moisture lignite multistage barrel burner should be adopted for staging combustion. The suitable type of plasma generator is DLZ-200 (70~105kW).
These boilers can realize oil free after PICS application. Especially for newly built units, tremendous investment saved after elimination of entire fuel oil system as well as large quantity of fuel oil during period of unit commissioning.
High-moisture Lignite
Aiming at high-moisture lignite, LY Power PICS applies bias concentration burner, DLZ-300 generator and modular large capacity power supply solving problems such as low initial ignition rate, poor adaptability for working conditions, pulverized coal accumulation inside burner, slagging, etc. Lignite with 35%~40% moisture can be effectively ignited.
Low Quality Bituminous and Lean Coal
Traditional PICS can not meet the requirements of ignition of 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 oxygen, the operating cost is about 10%~20% of origin.
