Unburned Carbon Online Analyser (UBC-2400).
What’s the benefit?
- The UBC-2400 provides automatic and continuous online information about UBC levels for combustion efficiency, coal mill performance, classifier assemblies and the quality of the fly-ash in changing conditions.
- It has a short response time due to placement close to the combustion zone, which allows the information to be used directly in the boiler control.
- The microwave measurement principle provides accurate information about the UBC levels, well within the standard industry standards and limits (optimum conditions are generally achieved when the carbon content in the fly-ash is 2-4 % by weight).
- By providing a physical fly ash samples, at request, the samples can be analysed in a laboratory. This allows for additional information regarding the combustion process, which can be used to further optimize the efficiency of the power plant.
- The double reference chamber and thermal conditioning allows for the device to be used in conditions all around the world, yielding accurate results at changing temperatures.
What does it do?
The Unburned Carbon Online Analyser 2400 (UBC-2400) provides the operators with automatic and continuous online information about the amount of unburned carbon (UBC) in post-combustion fly ash as well as physical samples for further laboratory testing. The UBC-2400 is typically used on large electric boilers firing with hard or brown coal. The UBC-2400 utilizes microwave technology which is especially suited for power plants combusting coal with a higher variance in properties due to sourcing from different coal mines. The UBC-2400 can be placed in the flue gas duct close to the combustion zone allowing the information regarding burn-out efficiency to be used directly in the boiler control room. In addition to the continuous measurement, the UBC-2400 can direct a physical sample into a bottle that enabling laboratory testing.
The UBC-2400 differs from the UBC-2200 due to its newly developed dual cell technology (reference chamber) which provides for even higher measurement accuracy of UBC levels. Furthermore, the dual cell technology eliminates the use of temperature control and an air conditioner unit.
Variant 1 (standard):
The UBC 2400 has one analyser unit connected to one control unit.
The UBC 2400 D has two analyser unit connected to one control unit
How does it do it?
The RCA-2400 consist of a control unit, an analyser unit and a collector unit.
Microwave technology provides highly accurate measurements for both lignites and hard coal and is compatible with coal of varying quality. The measurement principle is based on the established fact that microwave transmission properties relates to the amount of UBC in the ash sample. The fly ash sample is placed in a microwave resonance chamber, and its effect on the signal output is used to determine the UBC content of the ash.
The period of a sampling cycle depends on the flow of fly ash, and ranges from 3 to 15 minutes. The samples are obtained before the fly ash reaches the electrostatic precipitator, which gives a faster response time compared to traditional instruments. This rapid data acquisition allows for use directly in the boiler control, or as key parameters for the operators to quickly adjust the combustion process.
A double reference chamber with a known sample allows the device to correct for any temperature variations that do occur, thus giving more accurate measurements.
By allowing the samples to be either purged or collected in a sampling bottle, the operator may choose to collect samples after the analysis, which can be used for laboratory purposes.
What are the technical details?
Power supply: 230V/50Hz or as required
Power consumption: 750 Watt
Air supply: Min. 6 bar clean oil-free air
Sampling time: 3-15 minutes, depending on flow
Measurement range: 0-20% carbon in weight
Accuracy: +/- 0,25% residual carbon
Measurement output: 4-20mA, isolated current loop, 4mA=0%, 20mA=20% carbon
Dimensions: (WxHxD): Sampling unit: 600x600x350 mm
Control cabinet: 760x760x300 mm
Weight: Sampling unit: 55 kg
Control unit: 65 kg
Ambient temperature: Sampling unit: -20 °C – +40 °C
Control unit: -25 °C – +45 °C
The Sampling Unit
The pumping power is provided by utilising the pressure difference between the ambient and inside of the duct. The pressure difference drives an adjustable ejector. This design means that extraction velocity automatically adapts to changes in the flow rate in the duct.
The measurement principle is based on the established fact that microwave transmission properties relates to the amount of UBC in the ash sample. The fly ash sample is placed in a microwave resonance chamber, and its effect on the signal output of is used to determine the UBC content of the ash.
The Control Unit
The control unit undertakes the processing of the transducer signals and controls all functions of the individual RCA components. An operator’s control panel with display is located on the control cabinet front. The RCA-MI 2400 can be fitted with different communication technologies e.g. Bluetooth, WIFI and LAN, and a remote access system is also implemented.
The UBC-2400 is also available for installation in the hopper using a different extraction mechanism.
Nota Bene 1
The RCA is “only” an on-line trends measurements. It has to be verified with a reference. This could for instans be once every week. The big advantage of the RCA is that between the operators manual laboratory meassurement, continously, get a trending.