Assays of coal samples with the use of LIOS OnLine system on a real time basis

Ostec Instruments offers the industrial chemistry analyzer LIOS OnLine intended for quick and safe check of processes by means of continuous on-stream analysis of product’s chemical composition directly on conveyor belts or in pipelines for suspensions/liquids if such analyses are made on a real-time basis exclusive of sampling, delay in laboratory analysis and any types of hazardous radiation.

Ostec Instruments cooperates with coal and energy producers and knows how to respond to the challenge pertaining to high levels of ash and change in coal humidity resulting in a reduction in energy value of the product because losses in energy value give rise to claims of customers. Maintaining these parameters within given levels requires additional and considerable production costs.

Due to continuous monitoring of the content of coal components, such as ash, humidity, volatile matters, etc. you are able to manage the quality of products on a real-time basis:

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•   to exercise control over the quality of coal ores for sorting out of spec materials capable of reducing heating value, increasing ash content that could result in penalties;

•   to classify high-quality coal with minimal content of impurities (ash) for production of high-rank coal;

•   to establish stocks with high accuracy and predefined quality of coal for control of its proper blending during wet coal cleaning and for optimal dosing of magnetite;

•   to exercise control over the quality of coal on a real-time basis during loading onto vehicles for the purpose of refusing poor quality lots and preventing customers’ claims.

LIOS OnLine analyzer will allow you to:

•  enhance the effectiveness and improve stability of production processes;

• lower production costs of commercially useless materials removing them prior to further processing;

• reduce losses in feedstock;

• reduce operational costs thanks to savings in electrical energy, water, and reagents due to identification of process problems at early stages;

• provide your clients with quality products meeting all the requirements.

Based on feedback from our customers the typical payback period of LIOS OnLine is 3-9 months only.

LIOS OnLine analyzers are designed for automatic operation under industrial conditions of 24/7/365. Their reliability has been proved within a few years of production of various types of ores and minerals, including refractories, fertilizers, metals and economic minerals.

Technical Assignment

• Assessment of the feasibility of on-line LIBS analysis of coal on the conveyor belt
• Assay: Ash full content, heat value, humidity, coke content, volatile component content

Samples: 18 samples of fine powder coal from different coalmines.

 

The below table describes the chemical composition of samples submitted by the Customer based on the results of laboratory X-ray fluorescence (XRF) analysis:

Parameter	Range of values of samples submitted
	Min	Max
Ash (ADB)	24%	45%
Heat value GCV (ADB)	3,675 kcal/kg	5,080 kcal/kg
Humidity IM (ADB)	1.9 %	9 %
Volatile components VM (ADB)	21 %	28%
Coke (ADB)	29 %	40 %

Description of the Experiment

Experiments have been conducted with the use of LIOS OnLine analyzer. During measurements, the signal from 200 laser pulses has been accumulated in each sample for the purpose of obtaining adequate and reliable statistics. The samples have been rotating under laser rays radiated from the laboratory device imitating movements of the conveyor belt; in this way the entire surface of samples has been equally and uniformly affected.

Qualitative Spectrum Analysis

As seen from the diagram provided below spectra of components required for coal analysis and quality control may be clearly detected and identified (ash content, GCV, humidity, FC, VM).

Diagram No. 1. Typical LIBS spectrum of coal samples

Thus, calibration curves for assays may be calculated for all analysis parameters.

Quantitative Spectrum Analysis

On the basis of data on the chemical composition of samples, calibration curves “Lab vs LIBS” have been calculated. “Lab” has referred to laboratory data whereas “LIBS” – to data obtained with the use of laser LIOS OnLine analyzer.

Note: Two samples (indicated by orange color in the diagrams) have been selected as test patterns for the purpose of checking the calibration algorithm developed and therefore have not been included into the calibration set.

Correlation between LIOS OnLine analyzer data and laboratory values

Ash value

GCV

IM

VM

FC

The below table shows measurement errors calculated with the help of calibration curves.

Parameter	Range of values of samples analyzed (ADB)	R2	Mean-square deviation	Mean error
Ash value	24 - 45 %	0.93	1.12 %	0.92%
GCV	3,675-5,080 kcal/kg	0.92	85 kcal/kg	67 kcal/kg
IM	1.9 - 9 %	0.81	0.81%	0.76%
VM	21 - 28 %	0.88	0.49 %	0.40 %
FC	29 - 40 %	0.97	0.45 %	0.36 %

Sampling error, sample splitting and laboratory analytical error shall be taken into consideration for comparison the results of “LIBS” and “Lab” analyses.

Conclusion·        

• Good correlation between laboratory data and LIBS results and low analytical error (even for coal samples taken from different sources and with wide range of parameters) have demonstrated perfect applicability of LIOS OnLine system for coal analysis on the conveyor belt on a real-time basis.

• Implementation of LIOS OnLine system has provided analyses of the coal quality parameters required on a real-time basis with the use of LIBS safe and advanced technology free of neutron, X-ray and gamma radiation. There is no need for granting the license, observing safety measures and undergoing checkouts. There are no additional costs pertaining to replacement and disposal of radiation sources.