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Effects and impacts of components of coal handling system on coke quality and yield of coke plantsS. Steinbach, R. Neuwirth, Dr. R. Kim, ThyssenKrupp Industrial Solutions AG (TKIS), Germany

Motivation

Increased requirements for the quality of coke

A well designed coal handling system helps to improve the coke quality and to reduce the purchasing costs for coal at the same time

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Simon SteinbachThyssenKrupp Industrial Solutions AG

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Influencing Factors

• Grain size

distribution

• Coal moisture

• Additives

Summary

Plant Layout

• Blend crushing

concept

• Selective crushing

concept

Recommendations

• Selective screening

and crushing

• Coal moisture controle

Overview

Influencing Factors: Grain size distribution 1

normal raw coal has 30%

~ 50% of grain size < 3 mm

the caking ability of coal decreases when the fraction below 0.2 mm is increased

Separate grain size of4 ~ 6mm by screening before crushing to reduce the fraction below 0.2 mm

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Typical coal size distribution


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Ideal grain size distribution

size target ideal

<10 mm 100% 100%

< 3 mm 80~90% 100%

< 0.5 mm 34~40% 34%

*Simons W., Rubrecht E.: Optimaler Körnungsaufbau von Kokskohle, Essen, Germany, 1965

*


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GRAIN SIZE PERCENTAGEG

RA

IN S

IZE

*Simons W., Rubrecht E.: Optimaler Körnungsaufbau von Kokskohle, Essen, Germany, 1965

The higher the amount of small particles, the lower the bulk density

The bulk density influences the coke strength (M10 and M40)


Influencing Factors: Coal moisture 1

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Coal moisture control plants (CMCP) are common practice to control bulk density and reducing heating costs

Usual technologies are drum and fluidized drying

*Laske H.: Untersuchungsverfahren zur Charakterisierung fester Brennstoffe, VEB Deutscher Verlag für Grundstoffindustrie, Leipzig, Germany, 1961

*

Influencing Factors: Coal moisture 2

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Moisture control is recommended to stabilize to coking conditions

Optimum wall pressure can be achieved at 6% to 9% moisture content

*Deutsche Montan Technologie GmbH: Improved energy efficiency and coking process operation and control, Bulk density and internal gas pressure in large volume coke ovens, Germany, internal report

*

Influencing Factors: Additives

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0.1% ~ 0.5% of oil addition to the coal mixture, advantages:


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Increase of the bulk density without increasing the wall pressure

Flow of the charged coal characteristics are getting better

Reduces carry over

Less spillage coal amount

Overheating of the gas collecting space can be avoided

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Overview

Influencing Factors

• Grain size

distribution

• Coal moisture

• Additives

Summary

Plant Layout

• Blend crushing

concept


concept

Recommendations


and crushing


Plant Layout: Blend crushing concept

Problems:

hard coals are not crushed sufficiently

soft coals are crushed to an extremely fine grain size

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Simon SteinbachThyssenKrupp Industrial Solutions

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COAL TOWERBLENDING BINS CRUSHER

Plant Layout: Selective crushing concept

Profit: Control of grain size, moisture and additives leads to stable coking conditions and a better coke quality

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Simon SteinbachThyssenKrupp Industrial Solutions

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DRYERBLENDING BINSCRUSHER MIXER COAL TOWERSURGE BIN SCREEN

Overview

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Influencing Factors

• Grain size

distribution

• Coal moisture

• Additives

Summary

Plant Layout

• Blend crushing

concept


concept

Recommendations


and crushing


Selective crushing of each individual coal grade

Hard coking coals → coarse crushing

Hard coking coals + high swelling index → fine crushing

Softer coals → fine crushing

Particle size (<0.1 mm) → graphite deposits

→ carry-over

Recommendations for coal handling plants

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Fine grain >40% oiling →(0.1% ~ 0.5%) is advisable.

Pre-screening

Drying of coal to a constant moisture level

Combination of pneumatic classifying and drying upstream crushing.

Recommendations for coal handling plants

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Overview

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Influencing Factors

• Grain size distribution

• Coal moisture

• Additives

Summary

Plant Layout • Blend crushing

concept • Selective crushing

concept

Recommendations

• Selective screening and crushing


A well designed coal handling plant including:Pre-separation of fine particles before crushing

Selective crushing of each coal type

Coal moisture control

Mixing equipment for additives

Allows for:Use of increased portion of low-ranked coking coals

Reduction of cost for coal

Increase of coke quality

Improvement of coking conditions & battery life time

Summary

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Any questions?

For further information contact [email protected]

Thank you for your attention!


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www.metec-estad2015.com effects and impacts of components of coal handling system on coke quality...

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