The Hidden Cost of Coke Breeze in Sintering Operations
The 8-12% Problem
In most integrated steel plants, coke breeze accounts for 8-12% of the total sinter production cost. Yet this number is treated as a fixed cost. At ACL, we believe this assumption is costing Indian steelmakers tens of crores annually in unnecessary fuel spend.
Why Coke Breeze Efficiency Matters
The problem starts with how coke breeze combustion works inside a sintering machine. Coke particles need to reach ignition temperature, sustain combustion through the fire zone, and transfer heat efficiently to the ore mix above. In practice, a significant fraction of coke energy is lost to incomplete combustion, uneven heat distribution, and suboptimal flame front progression.
Where the Losses Actually Happen
Through thermal imaging and gas sampling at multiple sinter plants, we have mapped three distinct loss zones:
- Zone 1 - Ignition Layer: First 30-50mm of coke bed where volatile matter combustion dominates. Flame front is unstable here; 15-20% of coke at surface never ignites properly.
- Zone 2 - Main Fire Zone: Peak temperature region where coke carbon combines with oxygen. Uneven air distribution causes localised over-burning and under-burning zones.
- Zone 3 - Cooling Front: Downstream of the fire zone where residual CO and unburnt carbon compounds escape with exhaust gas.
How ACL's Sinter Additive Addresses Each Zone
Our sintering fuel additive is a spray-applied catalyst dosed onto the coke breeze feed conveyor at ultra-low rates (~0.1-0.2% on coke mass). It works across all three loss zones simultaneously.
Plant Trial Results: 7.2% Coke Reduction, Maintained Quality
In a trial at a 4.5 MTPA sinter plant in eastern India, ACL's sinter additive was dosed over a 45-day continuous run at 0.15% on coke breeze mass. Coke breeze rate reduced from 72.4 kg/tonne of sinter to 67.1 kg/tonne - a 7.3% reduction. All quality parameters maintained within plant specification bands. Payback period: under 3 weeks at prevailing coke prices.