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Measures to Improve Blast Furnace

Coke Quality and Yield

By :- PRASHANT KUMAR

DM- CO&CCD

SAIL-BHILAI STEEL PLANT

49th Coal Operating Committee Meeting

STATUS OF COKE OVEN BATTERIES IN BSP

4.3 mt tall Batteries

(8 nos.having 65 ovens each)

Batteries: 1 to 8

Oven Dimensions

Length: 14 mt

Avg Width: 407mm

Volume: 21.6m3

7 mt tall Batteries

(3 nos. having 67 ovens each)

Batteries: 9,10 & 11

Oven Dimensions

Length: 16 mt

Avg Width: 410 mm

Volume: 41.6 m3

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IMPROVING COKE QUALITY & YIELD

Coal Blend consistency

Uniform Heating & Thermal Regime

blend properties

Calibration of APD

Coal briquettes

Quenching Process

Consistent Pushing

Routine Cleaning

Monitoring CVT, EVT, CWT, FST

Coke Mass Temperature

Regulation

Stoichiometric ratio

Raw gas leakage

Coefficient of Pushing

Availability of equipments

Planning scheduled maintt.

Wet Quenching

Dry Quenching

Coal stock management

COAL BLEND CONSISTENCY

Continuous monitoring of coal blend

monitoring of crushing index

Monitoring of coal moisture

Coal stock management

Periodic drop test & Calibration of Automatic Proportioning Device (APD).

Addition of coal briquettes to improve Bulk Density in smaller batteries- thus to improve quality and yield

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Uniform Heating & Thermal Regime

Regulation – Monthly or as required

Control Vertical Temperature (CVT) - Once in A shift

Maintained as per daily pushing target

Kb ….. coefficient of battery above 0.98

End Vertical Temperature (EVT)- Monthly

(CVT – EVT) ~ 1200C

Cross wall temperature (CWT)- Monthly

should be uniform along the heating wall

Free space temperature Monthly

850 ± 500C at oven roof

Regenerator Temperature – Bimonthly

Coke Mass Temperature- Physically in all shifts

by pyrometer- weekly

Charge Level measurement bimonthly

and adjustment 300 mm free space from oven roof

Raw gas leakage Monthly

Stoichiometric ratio (A/F ratio) Weekly

For BF gas . . . 1.25

For CO gas . . . 1.45

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Consistent Pushing

Maintaining Coefficient of Pushing (+15 min of scheduled pushing time) above 0.9

Availability of equipments is high- more than 98%

Wireless Based Oven Identification, Machines Positioning & Interlocking, Scheduling Systems

Quenching process

Wet quenching- 10 out of 11 batteries uses wet quenching process

Optimum quenching and drainage time

Uniform receiving of Hot Coke Coke stabilization time in wharf

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Dry Quenching facility- Coke Dry Cooling Plant (CDCP)

Battery 11 is equipped with dry quenching facility

Better coke quality - as the coke is cooled gradually in the cooling chamber, it is free from internal cracks and surface pores.

Post carbonisation soaking in cooling chambers

Coke Quality Comparison

Parameter Wet Quenching Dry Quenching

M-10 7-8 5-7

M-40 79-81 84-86

Moisture Content 3%-5% 0.1%-0.8%

Coke Reactive Index

22-23 21-22

Coke Strength After Reaction

64-65 65-66

Volatile Matters 0.9% 0.8%

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THANKSTHANKS