Given the high ash content of Indian coal, how important the role of independent coal testing agencies?

High Ash Content in Indian Coal and Its Impact  

Ash content of coal produced in the country is generally 25 to 45 % whereas average ash content of imported coal varies from 10 to 20 %. Indian Coal has comparatively higher ash content than imported coal due to drift theory of formation of coal deposits in India. Coal seams formed due to drift theory contains higher ash as compared to in-situ theory of formation.



Impact of High Ash 

  • Ash is an impurity which will not burn.
  • Ash content is important in design of furnace grate, combustion volume, pol
  • lution control equipment (ESP) and ash handling plant.Ash increases transportation, handling, storage cost.
  • Ash affects combustion efficiency and boiler efficiency.
  • Ash causes clinkering and slagging problems in boiler.


Once the coal has been mined, it is usually processed to separate the inorganic, ash-forming components and to produce appropriately sized particles. The degree of preparation depends on the intended use of the coal, which is decided by coal analysis.


Coal analysis/testing are the most important data for coal producers and users. The accuracy of coal testing results helps in maximizing recovery, utilization aspect and optimization of coal preparation plants. 

The coals to be used for metallurgical purposes has the most stringent requirements like low ash and sulphur content, and bituminous rank coal. However, the thermal plants can utilize high ash coals, but the composition of ash plays a significant role in deciding the boiler and operating parameters.

Identification of the chemical composition of coal has a strong influence on its combustibility. Identification of sulphur content in coal and reducing sulphur in the fuel combusted also will reduce sulphate formation and fine particulate emissions and help to improve visibility by reducing regional haze. 

Indian coal is of mostly sub-bituminous rank, followed by bituminous and lignite (brown coal). The ash content in Indian coal ranges from 35% to 50%.

Testing results in a variety of improvements to plant operations, which directly affect the profitability of a coal plant, its ability to meet environmental requirements, and its ability to avoid future economic risks.

One of the major issues that are faced while designing a boiler is the behaviour of ash during the combustion process and management of coal ash. This can be curbed by testing a batch of coal and determining its properties. Coal testing help with a complete analysis of the quality of coal so that you can gauge the performance of the boiler design.

With the increasing stringent environmental policies, the accuracy of coal analysis results helps in optimizing disposal and storages of reject coal, coal slurries, fly ash and slag. A poor quality coal produces NOx, SOx and fly ash in reasonably large quantity as compared to good quality coal, so the pre-treatment before processing and disposal can enhance the economy of the plant. The coal analysis results provided by us, helps coal producers and processing industries in deciding the cleaning equipment, parameters, and probable amount of by-products. The optimization of by-products and pollutants not only save environment from poisonous hazards it also enhances the economy of the plant.


Role of Independent Testing Agencies


The independent, off-site testing laboratory focuses on its testing procedures to ensure accurate results. Companies often use the terms "third-party testing" or "tested by an independent laboratory" in advertising claims that guarantee that their test results are objective and free from the influence, guidance or control of interested parties. 

The independent laboratory focus on only one purpose to provide objective, analytical data on the quality of a product. Testing laboratories invests considerable time, money and effort to ensure this objectivity. In keeping with this agenda, testing labs usually keep considerable documentation on the internal processes that they follow to ensure objectivity and accuracy. 


Quality is not what happens when what you do matches your intentions. It is what happens when you do matches your customers’ expectations.

Therefore, Quality plays a very crucial role in Coal Production-Supply Chain.

Role of independent coal testing agency becomes very pronounced and very impacting particularly in India, because nearly 80% coal is supplied as crushed ROM (Run of Mine).

Independent coal testing agencies plays a vital role in coal and coke industries for selecting appropriate market and industry for the given coal. With the increasing stringent environmental policies, the accuracy of coal analysis results helps in optimizing disposal and storages of reject coal, coal slurries, fly ash and slag.

The coal analysis results provided by us, helps coal producers and processing industries in deciding the cleaning equipment, parameters, and probable amount of by-products.




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