DL/T 1127-2023 in English

Guide for design and operation of plasma ignition system

1 Scope

This document specifies the design and operation requirements for pulverized coal firing boiler using plasma-assisted ignition system.

This document is applicable to pulverized coal firing boilers with thermal power units with a capacity of more than 50MW, designed to burn bituminous coal or lignite, and adopt tangential or wall firing methods.

2 Normative references

The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

GB 50217 Standard for design of cables of electric power engineering
GB/T 4830 Industrial process measurement and control instruments - Pressure range and quality of air supply
DL/T 435
Code for the prevention of furnace explosions/implosions in power plant boilers
DL/T 5121 Code for design of thermal power plant air & flue gas ducts/ raw coal & pulverized coal piping
DL/T 5145 Technical code for design and calculations of coal pulverizing system of fossil-fired power plant
DL/T 5153 Technical rule for designing auxiliary power system of fossil fuel power plants
DL/T 5175 Code for design of on-off and modulating control of Instrumentation & Control for fossil fuel power plant
DL/T 5240 Technical code for design and calculation of combustion system of fossil-fired power plant
IEC 61000-2-2 Electromagnetic compatibility (EMC) - Part 2-2: Environment - Compatibility levels for lowfrequency conducted disturbances and signalling in public low-voltage power supply systems

 
3 Terms and definitions

For the purposes of this document, the following terms and definitions apply.

3.1
plasma

thermally ionized gas produced by ionization of an air medium, with anions and cations internally and taking on neutral externally

3.2
plasma generator

device that generates a plasma arc by ionizing a continuously supplied air medium using a stabilized power supply

3.3
anode of plasma generator

positively charged electrode in a plasma generator, referred to as the anode

3.4
cathode of plasma generator

negatively charged electrode in a plasma generator, referred to as the cathode

3.5
plasma-equipped burner

pulverized coal burner with plasma generator with plasma ignition and stabilized combustion

3.6
plasma-assisted ignition

process of igniting an air stream of a certain concentration of pulverized coal/air mixture in a plasma-equipped burner using a plasma arc generated by a plasma generator

3.7
air heater with steam

equipment for heating cold air at the coal pulverizer inlet with steam during cold startup of the boiler

3.8
air heater with oil combustor

oil combustor (usually for lignite) placed in the air ducts using a small output oil gun to provide hot air for the boiler's cold startup coal pulverizers

3.9
dense-lean particles separator

device for separating dense and light streams of pulverized coal/air mixture

3.10
flame video monitor

device for the operator to observe the flame burning situation through the video image acquisition and output of image video signal to the monitoring system

3.11
pulverized-coal concentration

mass flow ratio of pulverized coal to air in a pulverized coal/air mixture stream

3.12
mode for plasma-assisted ignition

mode of operation when the plasma generator is linked to the furnace safety supervision system (FSSS) and the plasma-assisted ignition function is activated during boiler startup or shutdown

3.13
mode for plasma-assisted combustion stabilization

mode of operation when the plasma generator is not linked to the furnace safety supervision system (FSSS) and the plasma-assisted ignition function is activated during boiler combustion stabilization

3.14
air medium system

system for supplying to the plasma generator the air medium, which is usually supplied by an air compressor, high-pressure centrifugal fan, or Roots fan

3.15
cooling water system

systems providing cooling water for plasma generator cathodes, anodes and coils

3.16
coal pulverizing system for boiler cold start-up

system that uses the coal pulverizing system of the furnace to prepare pulverized coal when the oil combustor of boiler burner is not activated for cold start-up, i.e., original coal pulverizing system plus air heater (air heater with steam or air heater with oil combustor) or system that draws hot air from the neighboring boiler to provide hot air for the coal pulverizers (including the corresponding piping, valves, and their control systems)

3.17
plasma-assisted ignition system

system consisting of a plasma-equipped burner, a power supply system, an air medium system, a cooling water system, a coal pulverizing system for boiler cold start-up, and a monitoring and control system

3.18
coal-fired power plant without oil/gas ignition system

coal-fired power plant that uses a plasma-assisted ignition system for boiler startup and shutdown and stabilized combustion, and does not have an oil (or gas) ignition system

4 Adaptability of plasma-assisted ignition system to coal quality

4.1 The boiler is designed to burn bituminous coal or lignite, and the plasma-assisted ignition system can be used when the coal quality characteristics meet the following requirements:

Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Adaptability of plasma-assisted ignition system to coal quality
5 Requirements for plasma-assisted ignition system performance
6 Plasma-assisted ignition system design and arrangement method
7 Coal pulverizing system for boiler cold start-up
8 Air medium system
9 Cooling water system
10 Power supply system
11 Monitoring and control system
12 Start, stop and operation of plasma-assisted ignition system
Annex A (Informative) Information required for the design of plasma-assisted ignition system