Online coal analyzer

Introduction

For coal fired power station, 70% of generating cost is spent on fuel. Coal quality is key factor that influences safe & economic operation of power plant. Lab analysis result is lagged behind for boiler combustion optimization. Online coal quality monitoring is of great significance for modern plant. Online coal analyzer can turn old extensive fuel management into new digital management for both coal quality and quantity. The system is not only used in power plant, but also in coal preparation plant, coking plant, cement plant, coal chemical plant, metallurgy plant, etc.

Application scenario

There are basically two scenarios of online coal analyzer in power plant;

• The system is installed on furnace feeding conveyor to measure coal as fired and provide guidance for combustion.
• The system is installed on plant inbound conveyor to measure coal as received for optimization of coal sorting and coal blending.

Analysis methods

LIBS, near-infrared & intermediate infrared spectroscopy, Raman spectroscopy.

Measures and indicators

M, moisture content

A, ash content

S, sulfuric content

H, hydrogen content

N, nitrogen content

V, volatile matter

FC, fixed carbon

Q, calorific value

Ash melting point

Maximum thickness of gelatine layer

HGI, Hardgrove Grindability Index

Benefits

• Accurate coal quality data, reduced fuel cost. Fossil fuel contributes major part of generating cost in thermal power plant. Lab analysis is not fast enough. Online coal analyzer can give in-time data of coal. Smart purchase decision for coal is based on boiler combustion characteristics. Online coal analyzer provides basis for decision making.

• Control of properties of blended coal. Now more and more power plants adopt coal blending to reduce cost. Quality variations of coal as fired will impact boiler combustion a lot, and bring huge difficulty for operation adjustment. Online coal analyzer can give quality data to reasonably contnrol mixed coal types and ratio.

• Optimized combustion, higher thermal efficiency. Frequent quality changes of coal as fired would bring down power plant safety and profits. By real-time analysis of coal quality indicators, boiler operators can make optimization in quick response including adjustment of pulverizing system, air/coal ratio, etc.

• Reduce slag formation, prevent unscheduled shutdown. By analysis of ash content and ash melting point, power plant can control combustion temperature to avoid molten ash attached on boiler tubes.