It is a study of coal properties which affects the coke making and its properties. It discusses coal storing place.

1. A
Seminar III
On
Influence of Coal Weathering on Coke Quality
1PIMPRI CHINCHWAD COLLEGE OF ENGINEERING NIGDI PUNE
Prepared by
Kailas Muke
Under The Guidance
Dr. Narendra Deore

2. OUTLINE
• Introduction
• Literature Review
• Literature Summary
• Problem Definition
• Objective
• Methods to Monitor
• Effect of Coal Weathering
• Testing of Coke Quality
• Case Study
• Summary
• References
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3.  Blast furnace is a type of metallurgical furnaces used for smelting to produce pig iron.
 Cokes, iron ores and hot air
 To increase the iron production as global demands
 Inner volumes of blast furnaces increasing gradually from 1000 m3 in 1960 to 5000 m3 in 2010 [5].
 Cokes quality
 Weathering effect on coke quality
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INTRODUCTION

4.  Coal weathering is a complex phenomenon involving several simultaneous and interacting chemical processes.
 Weathering includes oxidation as one of the cause of coal degradation.
 Causes of weathering
 Water
 Fluctuating temperature
 Plants
 Types of weathering
 Physical/Mechanical Weathering
 Chemical Weathering
 Biological Weathering
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INTRODUCTION contd…

5. LITERATURE REVIEW
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Sr.
No.
Author, Title of Paper, Journal, Year of
Publication
Paper Outcome Relevant point
1
P K Jha et. al., Effect of Weathering on Coal
Quality, International Proceedings of Economics
Development and Research, 2014
• Coal slurry pH measurement is
good indicator to monitor coal
weathering for Indian coal.
• FSI (Free Swelling
Index)
2
John C. Crelling et. al., Effects of weathered coal
on coking properties and coke quality, Fuel
Processing Technology, 1979.
Effects of weathered coal on coke
• Decrease in coke strength
• Increase in coke reactivity
• Increase in coke breeze
• Decrease in coking rate.
• Petrographic method

6. LITERATURE REVIEW contd…
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Sr.
No.
Author, Title of Paper, Journal, Year of
Publication
Paper Outcome Relevant point
3
P K Jha et. Al., Study the Effect of Weathering on
Coal and Coke Quality, International Journal of
Coal Preparation and Utilization,2016.
CSR decreased for
• Coal I by 2.7 %
• Coal II by 10.2 %
• Coal III by 41 %
• Alkali extraction
test
4
Fryeret, Al., Storage of Coal Samples, Alberta
Geological Survey, 1973.
• Changes in volatile matter
depends on the sensitivity of
aliphatic and alicyclic group to
oxidation
• The coking properties of the coal
deteriorate due to weathering.
• pH measurement

7. LITERATURE SUMMARY
 Metal production in the blast furnace decreases with coke stability.
 Due to weathering coking rate decreases which limits the coke production.
 An increase of weathered in the coal blend; coke stability and coking rate decreased.
 In carbonization process, coke making properties of coal reduced which are Free swelling index and fluidity
get reduced.
 Coal slurry pH measurement is good method to monitor coal weathering.
 Low rank coal deteriorate at a faster rate because low rank coal are dominated by free radicals, that easily react
with oxygen.
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8. PROBLEM DEFINITION
Weathering of coal affect the coal properties and coke quality.
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OBJECTIVES
 To study the effect of coal weathering on coal properties
 To study the effect of weathered coal on coke quality with help of case study

9. METHODS TO MONITOR COAL WEATHERING
 Alkali extraction test
 Fourier Transform Infrared Spectroscopy [FT-IS]
 Petrography
 Thermogravimetry
 Coal slurry pH measurement
 Free swelling index
 Froth flotation
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10. METHODS TO MONITOR COAL WEATHERING contd…
 Alkali extraction test
- In this test, coal is boiled in caustic solution, oxidized coal dissolved and darkened the solution.
- Light transmittance of the solution was determined by UV- visible –spectroscopy at 520 nm (nano meter).
- In the case of weathered coal, caustic solution extract weak acids produced during weathering so if
transmittance is below 100 % it means coal is weathered. Lower the transmittance value means more the degree
of weathering in coal.
- If the transmittance value is less than 80%, then the coal is not suitable for metallurgical purposes[7].
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11. METHODS TO MONITOR COAL WEATHERING contd…
 Fourier Transform Infrared Spectroscopy [FT-IS]
- In infrared spectroscopy, IR radiation is passed through a sample. Some of the infrared radiation is absorbed
by the sample and some of it is passed through (transmitted). The resulting spectrum represents the molecular
absorption and transmission, creating a molecular fingerprint of the sample. Like a fingerprint no two unique
molecular structures produce the same infrared spectrum.
- Fourier transform infrared (FT-IR) spectroscopy is a
widely used analytical technique for determining the different
functional groups of a coal structure.
Pimpri Chinchwad College of Engineering, Pune 11The Spectrometer[6]

12. METHODS TO MONITOR COAL WEATHERING contd…
 Petrography
- Coal petrography is a microscopic technique used to determine a coal’s rank (degree of coalification).
- Rank is determined by measuring the percent light reflectance of the maceral vitrinite.
- Petrography is primarily used as a tool to evaluate bituminous coals and coal blends in terms of their ability
to produce blast furnace coke.
- Coal petrography can also be used to determine whether contaminants are present in the coal and to detect
oxidized coal in the sample.
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13. METHODS TO MONITOR COAL WEATHERING contd…
 Coal slurry pH measurement
In this test 2 gm of coal and 20 ml distilled water has been heated to 150 0C for two hrs. Then it
is cooled by tap water indirectly. Coal slurry will be transferred to beaker and its pH has been determined by
respective probes.
 Forth floatation
- Froth flotation is a process for selectively separating hydrophobic materials from hydrophilic.
- The flotation process is used for the separation of a large range of sulfides, carbonates and oxides prior to
further refinement. Phosphates and coal are also upgraded (purified) by flotation technology.
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14.  Effect of weathering on coal quality
 Affect beneficiation process of coal
 Alteration in coal technological properties and size degradation.
 Rapid deterioration in fluidity and reduction in plastic range.
 Weathering includes oxidation as one of the cause of coal degradation.
 Reduction in calorific value
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EFFECT OF COAL WEATHERING
Coal Rank % increase in oxygen Kcal loss/kg
Low rank coal 1 106
High rank coal 1 133
Oxidation reduces calorific value[3]

15. Some of the tests are used to measure the physical properties of blast furnace coke.
 Coke reactivity index (CRI) and Coke strength after reaction (CSR)
 The CRI/CSR test measures coke reactivity in carbon dioxide at elevated temperatures and its strength after reaction
by tumbling.
 In the test, 200g of 19 x 22 mm sized coke is reacted in a vessel with CO2 gas for 2 hours at 1100°C.
 CRI=> The weight loss after the reaction equals the CRI.
 CSR=> The reacted coke is then tumbled in an I-shaped tumbler for 600 revolutions at 20 rpm and is then weighed.
The weight percent of the coke equals the CSR.
 For most of the blast furnace; CRI < 25, CSR > 60
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TESTING OF COKE QUALITY

16. CASE STUDY
 To study the weathering effect on coke quality 3 types of coal samples are selected (H-1, H-2 and H-3).
 Storage conditions
 Summer – H-1 and H-2
 Winter – H -1 and H-3
 Storage time- 2 months
 Stored quantity- 3 tons (Approximately)
 Coal analysis method
Ash values, volatile matter content, FSI, Petrographic
analysis, Transmittance by alkali extraction test and
pH of coal slurry
• Coke analysis
• CRI and CSR
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Coal Properties
Initial Storage Condition
Summer Winter
H-1 H-2 H-1 H-3
Ash, % 8.9 9.2 9 6.7
Volatile matter, % 25 25.6 24 27.5
Mean max reflectance, % 1.25 1.11 1.24 1.23
Fluidity, ddpm 500 2000 600 50
Free swelling index 5.5 5.5 5 3.5
Average size, mm 2.98 2.79 2.98 2.16
Characteristic of coal stored for study[3]

17. CASE STUDY contd….
 Changes in coal properties
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Storage
period
Coal
source
FSI pH Transmittance, % Volatile matter, % Vitrinite, %
Storage, Day Storage, Day Storage, Day Storage, Day Storage, Day
1 60 1 60 1 60 1 60 1 60
Summer
H-1 5.5 5.5 6.1 6.05 99.25 97.61 25 24 65 62.1
H-2 5.5 5.5 4.65 3.65 92.74 84.99 25.6 25.5 64.4 61.4
Winter
H-1 5.0 5.0 7.0 6.95 95.58 94.15 24.0 23.0 65.0 62.2
H-3 3.5 3.5 5.10 4.96 39.91 25.12 27.5 27 85.0 84.6
Change in coal quality before and after 2 months of Storage [3]

18.  Changes in coal characteristics
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0
1
2
3
4
5
6
7
8
0.05
1.64
1
2.9
1
7.75
0.1
3
H-1
H-2
0
2
4
6
8
10
12
14
16
0.05
1.43 1
2.8
0.15
14.7
0.1 0.4
H-1
H-3
CASE STUDY contd….
During summer During winter

19. CASE STUDY contd….
 Changes in coke properties
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Coke
properties
Summer Winter
H-1 H-2 H-1 H-3
Storage, Day Storage, Day Storage, Day Storage, Day
1 60 1 60 1 60 1 60
CSR, % 61.1 57.6 22.4 21.8 51.2 43.7 40.4 23.8
CRI, % 25.9 29.4 45.1 44.5 32.1 36.9 37.6 42.1
Change in coke quality on storage [3]

20. CASE STUDY contd….
 Changes in coke properties
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0
2
4
6
8
10
12
14
CSR, % CRI,%
5.7
13.5
2.7
4.4
H-1
H-2
0
10
20
30
40
50
CSR, % CRI, %
40.4
37.6
41.1
11.9
H-1
H-3
During summer During winter

21. SUMMARY
 The properties of weathered coal have effect on coke properties.
 Monitoring of coal weathering is necessary to get good quality coke.
 Most blast furnaces require a coke with a CSR greater than 60 and CRI less than 25.
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22. REFERENCES
1. P K Jha, Dr. T K Das, Dr. A B Soni, “Effect of Weathering on Coal Quality”, International Proceedings of
Economics Development and Research, 2014.
2. John C. Crelling, Raymond H. Schrader, Louis G. Benedict, “Effects of weathered coal on coking properties
and coke quality”, Fuel Processing Technology, 1979.
3. P K Jha, Dr. T K Das, Dr. A B Soni, “Study the Effect of Weathering on Coal and Coke Quality”,
International Journal of Coal Preparation and Utilization,2016.
4. Report of Indian Chamber of Commerce on, “Bridging the gap: Increasing coal production and sector
augmentation”, June 2016.
5. Prof. Veena Sahajwalla, Dr. Sushil Gupta, thesis report on, “Effect of Weathering on Coal Characteristics”,
July 2012.
6. Fryer, J. F. and Szladow, A. J., “Storage of Coal Samples”, Alberta Geological Survey, 1973.
7. Lowenhaupt, D.E., Gray, R.J., “The alkali-extraction tests as a reliable method of detecting oxidized
metallurgical coal”, International Journal Coal Geology, 1980.
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23. THANK YOU!!!
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