7 December 2023

Coal proximate Analysis

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Coal proximate Analysis


  1. Introduction of Coal
  2. Composition of Coal
  3. Uses of Coal in Power Plant
  4. Important Coal Analysis
  5. Effect of Improper Analysis
  6. Type Of Coal Analysis
  7. Coal Proximate Analysis
  8. Different Coal Analysis Report


1.) Introduction of Coal:-

  • Coal is a combusible black or brownish sedimentory rock usually occurring in rock in layers called coal beds.
  • Coal is composed primarily of carbon along with variable quantities of other elements, chiefly hydrogen, sulpher, oxygen, and nitrogen
  • Type of Coal:-
  1. Lignite
  2. Bituminous
  3. Anthracite

3.) Uses of coal – Power Plant

  • Used for boiler water heating and generates steam in power plant for power generation.
  • When coal is used for electricity generation, it is usually pulverized and then combusted (burned) in a furnace with a boiler. The furnace heat converts boiler water to steam, and generate power.

4.) Important of Coal Testing

  • Coal is a highly heterogeneous substance in terms of the inorganic and organic. An estimation of the true value of the desired parameters of a bulk material
  • The basic purpose of collecting and preparing a sample of coal is to provide a test results of representative of the lot sampled.
  • Definite number of increments distributed throughout the whole volume of coal And prepare gross sample
  • Samples may be required for technical evaluation, process control, quality control and commercial transactions.
  • For quality assessment of coals from new sources, samples are to be drawn from coal seams,
  • To check the quality of coal for boiler , To collect the sample from Grizzly hoper for GCV calculation.
  • The sampling procedure will depend mainly on the nature of sample collection as from moving belt or from stationary lots like wagons, stockpiles

5.) Effect of improper sampling

  • Impact on cost
  • Showing wrong test result
  • Delay in making correct decision
  • Uneven process problem
  • Supply delay from party side

6.) Sampling of Coal (IS:436 – 1964, Part -1)

  • Coal sample collection can be carried out by difference location as below

1) Wagon (Railway)

2) Coal Yard / Stock Pile

3) Conveyer Belt

  • Sample collection to be done by mechanical uses, No in manual
  • At the time of sampling, all accessories and chemist are present for proper and correct sample collection
  • Sampling Scoop must be available at the time of sampling

A.) Sampling From Wagon (Coal Rack)

  • About 7 kg of coal sample is drawn from each wagon from upper, middle and bottom layer by digging or the time of loading and unloading.
  • Sub lot sample are made for each 5 wagons by mixing of 7 kg sample form each wagon (35 kg approx).
  • Each sub lot sample separately crushed in jaw crusher to reduce the size below 10 mm and mix. Reduce the sample qty by quartering and coning up to 2 kg each.
  • Mix each sub lot sample (2 kg x12) and get 25 kg of coal sample for lab.
  • Finally 25 kg sample reduced by quartering and conning for final sample of 4 Kg (size – 10 to 12.5 mm).

Wagon Sample Collector (Sampler)

B.) Sampling from Coal Yard (Stock Pile)

  • The quantity of coal in stock pile shall be divided into suitable number of sub lot (Refer Table – 1)
  • Surface of each lot shall be leveled and one point for approx 250 MT for each sub lot
  • Height of stock pile is below1.5 M then digging required 50 cm diameter  if more then digging 1.5 meter for sampling

  • Each sub lot crushed by jaw crusher and get final sample up to 4 Kg (As per above procedure) size are 10 or 12.5 mm
  • Weight of gross sample to be taken

C.) Sampling From Conveyer Belt ( As per IS:436-1964 , Part-1)

  • Insert the scoop on stopped conveyor belt (Must stop the belt for proper sampling over the cross area).
  • Brush or broom to aid for removing fine particle from belt
  • Obtain at least three increment for each belt for correct sampling to minimized error.
  • Required accessories as polyphone bags and tags available.
  • Safety equipment such as Helmet, hand gloves and eye glasses , and dust mask should be wear by sample collector.
  • For number of sub lot taken (Refer Table-1)
  • Wt of gross sample and number of increment taken from conveyor, Refer table -3
  • After appropriate gross sample collection (see above) and reduce by quartering & coning methods
  • Finally prepare 4 kg sample (10 mm size) for lab analysis

Online Sampler (Conveyor Belt)

7.) Coal Sample Preparation

(1) Run Of Mines Coal (0 to 230 mm) IS :436 – 1964:-

  • 4 Kg coal (12.5 mm) sample drawn in laboratory (Above)
  • To reduce the sample up 3.35 mm by palmac type reduction mill .
  • The crush material shall be reduce by quartering and conning methods till 2 kg obtains
  • Crush the sample by pulverize (Mill type) and shall final all sample ground to pass 212 micron IS sieve from the ground pass material , 1.5 kg sample to be taken for laboratory sample
  • Each laboratory sample shall be divided into three equal part (Supplier, Testing and Reference)
  • Sample kept in Polyethylene bags with sealed

(2) Large Coal (5 to 150 mm) IS 436 -1964, Part-1 :-

  • 4 Kg coal (12.5 mm) sample drawn in laboratory and follow the procedure same above for laboratory sample
  • Each laboratory (212 Micron size) sample (1.5 Kg) shall divided into three part for Supplier, Lab and Reference sample

(3) Small coal (0 to 50 mm) IS: 436 – 1964, Part – 1:-

    • 4 Kg coal (12.5 mm) sample drawn in laboratory and follow the procedure same above for laboratory sample
    • Each laboratory (212 Micron size) sample (1.5 Kg) shall divided into three part for Supplier, Lab and Reference sample

Pulverizer Coal Mill (Aimil)

8.) Reduction Of Gross Samples (As per IS:436-1964,Part-1

9.) Coal Analysis Report(Proximate)

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