SAMPLERS – equipment for mechanically extraction of samples from a wide range of dry granular materials like mineral ore, solid biofuel, coal, brown coal, lignite, lime stone, gravel and electronic scrap.
These machines take cuts or increments, taken from a moving stream of material and are designed to comply with any requirements
- BUCKET SAMPLER – The Cross Belt Bucket Sampler (CBBS) is designed to take out a representative sample of powdered material and lumps up to 100 mm, from a free falling flow of materials.
- CHUTE SAMPLER FP – The Chute Sampler (FP) is designed to take out increments of non-sticky powdered material and lumps up to 40 mm, in a closed pipe system, from a free falling flow of materials
- CHUTE SAMPLER FPMX – The Chute Sampler (FPMX) is designed to take out increments of non-sticky powdered material and lumps up to 40 mm, in a closed pipe system, from a free falling flow of materials and collecting these in a mixing tank for establishment of mean samples.
- DOUBLE CHUTE SAMPLER – The Double Chute Sampler (DFP) is designed to take out increments of non-sticky powdered material and lumps up to 40 mm, from a free-falling flow of materials in a closed pipe system.
- HAMMER SAMPLER – The Cross Belt Hammer Sampler (HP) is designed to take out a representative sample of powdered material and lumps up to 200 mm, from the material on an operating rubber belt conveyor without stopping the belt
- AIR SLIDE SAMPLER – The Air Slide Sampler (AS) is designed for continuous or intermittent sample extraction of dry, non-sticky powdered material flowing in air slides. The Air Slide Sampler can be installed in any existing air slide within a couple of hours. This equipment is well suited for cement, raw meal, sand and other powdery material.
- SCREW SAMPLER SCR – The Screw Sampler (SCR) is designed for sample extraction of dry, non-sticky powdered material from a free falling flow of materials. Well suited for cement, raw meal, sand and other powdery material.
- SCREW SAMPLER SMX – The Screw Sampler with Mixing Tank (SMX) is designed to create an average sample from continuous extraction of dry, non-sticky powdered material from a free falling flow of materials. Well suited for cement, raw meal, sand and other powdery material
- RCA-MI RESIDUAL CABON ANALYSER MICROWAVE – ONLINE MONITORING OF FLY ASH – The Residual Carbon Analyser Microwave (RCA-MI) provides the operators with vital real time information about the combustion efficiency through continuous monitoring of the
unburnt carbon content in the fly ash. The RCA-MI will assist coal fired power plants by improving
their operation in the following three areas:
• Combustion efficiency
• Coal mill performance
• Production of high quality fly ash for sale
1. The Ash Sampler – The pumping power is provided by utilising the pressure difference between the ambient and inside of the duct. This pressure difference drives an adjustable ejector. This design
also means that extraction velocity automatically adapts to changes in the flow rate in the duct.
2. The Transducer – The measurement principle is based on the established fact that microwave transmission properties relates to the amount of unburned carbon in the ash sample. The critical electronics circuits are embedded in the transducer to obtain optimal results.
3. 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.
4. Combustion Efficiency – The RCA-MI measures the value of unburnt carbon in the fly ash. Through a constant control of these on-line measurements the operator can quickly make the necessary adjustments to the combustion process thus securing a more complete combustion of the coal and thereby reduce the environmental impact and the amount of fuel needed.
5. Coal Mill Performance – Any increase in the amount of unburnt carbon in the fly ash is immediately observed by the operator and makes it possible to advice on control and adjustment of the coal mills.
The increased carbon content could indicate that the mill performance has decreased, i.e. particle size has gone up and adjustments of the mills are needed.
- REPRESENTATIVE SAMPLING SYSTEM- RSS
Knowledge of the raw coal properties:
- Heat value
- Moisture content
- Hardness (Hard Grove Index)
- N content
- S content
- Ash percentage
is essential when optimizing the combustion process at coal fired power plants.
The properties are identified by taking representative samples from each coal batch used at the power plant.
The Raw Coal Sampling System is an integrated part of the control system available to the power plant operators.
The Sampling System provides the operator with the means for executing the extraction and preparation of representative samples of the coal.
The sample size is suitable for making laboratory analysis.
The Raw Coal Sampling System operates in accordance with approved international standards.
The results of the laboratory tests performed on the basis of the representative samples prepared by the sampling system are used for:
- Calculating the payment due for each batch of coal supplied.
- Adjusting the coal flow to the mills.
- Calculating the amount of by-products from each batch.
Calculating the emissions from each batch of coal.
In order to verify the coal properties for a given coal lot it is necessary to take out a number u of sampling units. This number depends on the mass of the lot and on the desired overall sampling precision. Minimum requirements are listed in Table 1.
Each sampling unit is taken by the sampling equipment as n increments, where n should be 10 or more.
The properties of the coal lot can be determined with an overall precision PL using equation 1 where:
- VPT is variance of sample preparation and test. If no data
- available: Assume 0.2
- VI is the variance of primary increment. If no data available: Assume 20
The overall precision is a function of the number of sampling units u, the variance of sample preparation and test VPT, the number of increments n and the variance of the increments VI.
If a given precision PL is required the number of increments n and the number of sampling units u can be found using Equation 2 and 3 respectively.
The values n and u are adjusted upwards and recalculated to a convenient combination respecting the required minimum values.
The mass of each primary increment can be calculated using
Equation 4 where:
- C is flow rate [t/h] on conveyor belt.
- A is cutting aperture [mm].
Should be ≥ 3 times the nominal top size of coal.
- S is cutter speed [m/s].
If S is constant the incremental mass is a function of the flow rate C, the nominal top size of the coal lumps and cutting aperture A.
As a guideline for lay-out of sampling systems the reference increment mass from Table 2 should be used as minimum values.
The total mass of the sample (sampling unit) is at least n times the increment mass where n is at least 10 as previously discussed.
To obtain convenient sample masses, the sample is divided into a number of statistically identical but smaller samples and a rest which is returned to the coal conveyor.
From the preceding section is seen, that reducing the mass needs a reduction in particle size in order to preserve the representative nature of the sample. For this reason a system for extraction of representative samples of coal consists of multistage extraction, particle reduction and division equipment.