Laboratory Coal Analyser WILPO L 241

Purpose of the analyzer

The WILPO L 241 Analyser is designed for rapid determination of basic coal quality parameters (ash [A^r], moisture [W_t^r] and sulphur [S_t^r] and immediate determination of the calorific value [Q^r_i] in technical coal samples (in working condition).

The design of the unit and original, patented measurement methods enable the analyser to be used in laboratories in mines, power plants, heat generating plants, coke plants, and also in on-site testing laboratories, storage yards, etc.

Our most recent development among analysers, the WILPO L 241, can measure four basic coal quality parameters with higher accuracy than WILPO L 132 / L 142 analysers and eliminate or minimize the impact of chemical composition variability of coal on measurement results.

General structure and principle of operation

The WILPO L 241 Analyser is designed as a single-module unit, which enables its easy use in any place.

The measurement vessel with the coal (or e.g. biomass) sample, upon placing it on the loader, is positioned precisely between probes in the measurement paths. During measurement the vessel is slowly rotated so that the entire sample is shifted many times between the probes. The sample is exposed to gamma rays, X-rays and microwaves and the measurement signals (electric pulses) from respective measurement paths are relayed to the control and measurement module, where they are counted and processed. Results of every measurement, along with additional information entered from the keyboard, such as sample number, coal buyer, etc., appear on the display and are automatically saved in computer memory.

The database that is created enables printing out of results as required by the user, e.g. results from a period of one month for coal sent to a selected buyer or provided by a selected supplier, results for samples analysed during one day with daily mean values of coal quality parameters, etc. The latest probes, electronic large-scale integration components and a fast computer system with printer provide reliable and accurate operation, as well as comfort of use.

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Fig. 1 shows a simplified diagram of the analyzer, where:

1 and 5 – transmitting and receiving microwave antennas
2 – microwave radiation beam
3 – coal sample
4 – rotating measuring vessel
6 – container with radiation source and target positioning system
7 – X- and gamma-ray beam
8 – ionizing radiation detector
9 – control and measurement module

Analyzer operation

Construction

A ca. 1 kg sample, in as-is condition, is poured into a crusher (preferably a roll crusher, e.g. LAB-08-240), where it is comminuted. Afterwards the coal sample comminuted to grain size 0 to 6 mm is poured, without weighing and drying, to the measurement vessel and the top surface of coal is levelled with the roller, which is part of instrument equipment (the measurement method applied eliminates the effect of sample packing on measurement results). The sample is levelled with the roller in order to ensure complete filling of the vessel and thereby to ensure proper measurement.

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Measurement implementation:

The carrying out of measurement is simple and consists of placing the vessel with the sample on the analyser loader, pushing the loader into the analyser and pressing the start button on the keyboard. Functions of important keys are shown on the display. Measurement takes 200 seconds, after which measurement results are displayed and automatically entered into the database. Details of analyser operation and database handling are given in the Analyser Operating Manual.

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Operational safety

The Analyser is an isotopic instrument with a low-energy gamma radiation source. The design of the instrument ensures complete safety of its operation.

Its manufacture has been approved by the State Atomic Energy Agency in Warsaw (permit no. D-14478 of 11.09.2002, annex no. 1 of 2.02.2006).

Basic technical data

Measuring material:	hard and brown coal, coal waste, ashes (combustible parts), biomass
Coal sample granulation:	approx. 0 – 6 mm
Weight of the measurement sample:	0.4 – 0.7 kg depending on the type of coal, ash content and degree of packing, without the need to weigh
Sample preparation time:	approx. 100 pp
Measurement time	200 s
Ash and sulphur determination method	absorption of gamma and X-rays
Radiation source:	Am-241 isotope, activity ca. 4 GBq, in a protective container of special design
Moisture content measurement method:	absorption of microwave radiation
Characteristics of microwave radiation:	frequency ~9.35 GHz power: approx. 1 mW

Measurement accuracies defined as average, absolute values, depending on the type of coal and measurement range

VALUE MEASURED	COAL TYPE AND RANGE OF VARIATION OF MEASURED VALUE	MEASUREMENT ERROR σ
Ash content A^r	Thick assortments and some rinsed assortments 2 – 10% pop. Some assortments were washed and had raw ash content of 10 – 25%.	0,5 – 0,7 % 0,5 – 1,0 %
	They had raw – 15 – 35% ash content	0,7 – 1,0 %
	Overgrowths and waste – 25 – 50% ash content	1,0 – 1,5 %
	Waste and stone – 50 – 85% ash content	1,5 – 2,0 %
Moisture content W_t^r	Range 2 – 10% moisture content	0,5 – 0,7 %
Moisture content W_t^r	Range 10 – 25% moisture content	0,7 – 1,0 %
S sulfur content_t^r	Range 0.2 – 1.0% sulfur content	0,05 – 0,10%
	Range 0.5 – 1.5% sulfur content	0,1 – 0,15%
	Range 1.0 – 3.0% sulfur content	0,1 – 0,2%
Calorific value Q_i^r	Complete range	100 – 500 kJ/kg
Combustibles content	Complete range	ok. 0,5 %

Dimensions of the analyzer module: 1000 x 800 x 1550 mm
Weight: approximately 95 kg
Power supply: 230V (±10%), 50 Hz