General:
The carbon content of boiler flyash is an important parameter that reflects the combustion efficiency of a coal-firing boiler in the thermal power plant. Method of loss of weight by ignition traditionally adopted for measuring the flyash carbon content is an off-line laboratory analysis method, which requires high typicality of the ash sample and brings about lagging analysis, making it difficult to quickly reflect the combustion condition of the boiler. Real time measurement of flyash carbon content will guide the operation personnel to correct adjustment of the air-coal flow ratio and improved boiler combustion control level. Control of the flyash carbon to a reasonable level will help reduce the power generation cost and enhance the cost effectiveness of the operating unit.
System principle:
Use the microwave resonance measurement technology to analyze and determine the content of carbon in the flyash on the basis of the absorption of the microwave resonance energy by the incompletely burnt carbon in the flyash.
The system uses the auto-extraction type dynamic sampler without external power to automatically collect the ash sample at constant rate from the flue gas duct into the microwave measurement tube and automatically judge the level of the collected ash. When sufficient ash sample is collected, the system will make microwave resonance measurement of the flyash carbon.
Main function:
1.Carbon content value and curve display
2.Synchronous ash reserving function
3.Flyash carbon beyond limit alarm
4.Carbon content analogue signal output
5.Off-line data browse and analysis
System construction:
In the light of the fact that two flue gas ducts are adopted for fly ash emission on most of the boilers of domestic units above 100MW, the device is designed to have two independent flyash sampling and microwave measurement systems which share one common electric control and main processing system.
Main indexes:
1. Measurement range: 0”«12%(normal measurement range)
2. Measurement accuracy: 0.5% (representative value, carbon content in 0”«6%)
0. 8% £Ørepresentative value, carbon content in 6”«12%£©
3. Measurement cycle: 2~6 min.
4. Historical data: maintained for 12 months
5. Power consumption: 220VAC£¬average 0.5kW£¬most 2.2kW
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