RAB presentation

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Some RelevantTechnical IssuesonConsistent Coal
Quality Asim Chowdhuri Dr Kalyan Sen, CFRI,
2003
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Approach towards Quality Improvement Supply of
Consistent Quality

• Proper QMS
• Technological options for Quality
  enhancement
• Modification of Standards
• Revision of Coal Categorisation

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Existing Quality Monitoring System

• Manual sampling
• Wagon top sampling
• Mechanical sampling

Constraints Handling of large sized coal
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Quality Monitoring of Coal
Problems of Wagon top sampling

• Sampling sites
• Inadequate facility - sampling, preparation
  analysis
• Insufficient time, manpower, etc.
• Results sampling from top only

How it affects final results

• Less reliable due to higher errors
• Disputes between supplier consumer
• Nation being the ultimate looser

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Quality Monitoring of Coal
Problems of Mechanical Sampling(200mm sized coal)
Constraints

• Higher Bias leading to disputes
• High Spillage
• Frequent Chute choking
• Rapid wear Tear
• High Capital investment Maintenance costs

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Proposed Modification in SamplingProcedure

• Supply of lower size coals (50 mm or below)
  and inclusion of AMS

• Benefits
• More reliable quality data
• Less Capital investment
• Low maintenance cost
• in case of temporary failure of AMS theadvantage
  would be for switching over towagon top sampling
  with better precisionthan that for higher sized
  coals

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Identified Technological Optionsfor Coal Quality
Upgradation

• Globally accepted Options for better
  economicsand less environmental pollution
• Mine planning
• Dry deshaling at Pit heads
• Judicious blending
• Wet beneficiation

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Identified Technological Optionsfor Coal Quality
Upgradation
Present rider ash level of 34
Proposed The degree of washing should be limited
to that density of cut at which the final product
is free from any particle of ash higher than
50-55. Of course, this often leads to
overallash content level more or less 34.
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Technology Routes for beneficiation
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Proposed Modification of Standards

• Adoption of ISO 13909 (Mechanical Sampling)
• Adoption of ISO 9931 (for Pulverized Coal)
• Reaffirmation of IS 13810 (Code for FS)
• Change in ISO 1213 -1 (a new term)
• Characteristic Ash
• The ash of the particles in a closely spaced
  relative density fraction obtained from Float
  Sink analysis

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Revision of Coal Categorisationfor commercial
purpose

• Categorisation system based on GCV (as recd.
  Moist. basis) weightage on the ash
• A Matrix system with closely spaced GCV ash
  value.
• Coal quality could be assessed by maximum ash
  value and lowest GCV value that will
• Remove anomalies of the present system
• Provide incentive for better quality
• Ensure consistent quality of a consignment

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