CASE23 · Manufacturing · Smelting fumers
Combining feed allocation and fuel/oxygen control in zinc smelting
Two fumers differ in feed mix and energy intensity. A proposal combines slag/feed redistribution with real-time flue-gas O₂/CO feedback to reduce excessive fuel and oxygen input.
01 · CASE ANALYSIS
Operating challenge
Coal and oxygen costs were large, and the two fumers operated with different feed mixtures and intensities. Changing feed properties affected combustion while existing utility controls could not always respond promptly.
Flue-gas O₂ and CO varied over time and between units, indicating a need to distinguish incomplete-combustion losses from excessive oxygen input.
02 · CASE ANALYSIS
Data and correlations
The analysis combined feed composition/input, throughput, coal/oxygen consumption, quality, equipment condition and flue-gas records. Higher slag proportion was associated with lower energy intensity.
One fumer’s seasonal intensity variation reached approximately 40.2%, compared with 4.4% for the other. Coal demand was examined against throughput, and oxygen against fuel input and combustion state. These are operating relationships, not standalone savings results.
| Relationship | Reported observation |
|---|---|
| Slag fraction and energy intensity | Higher slag proportion associated with lower intensity |
| Seasonal intensity variability | 40.2% for one unit; 4.4% for the other |
| Throughput and coal | Coal consumption increases with throughput |
| Coal, oxygen and O₂/CO | Fuel changes interact with combustion state |
03 · CASE ANALYSIS
Integrated proposal
Redistribute slag/feed mix toward approximately 30% while maintaining total throughput. The source simulation estimates approximately KRW 2.8 billion/year but does not separately account for slag transport cost.
Add O₂/CO analyzers and PLC-based closed-loop control for the two units. Fuel and oxygen setpoints are adjusted according to combustion condition to limit both unburned fuel and excess high-cost oxygen.
04 · CASE ANALYSIS
Expected economics and verification
The flue-gas-control proposal assumes approximately 1.8% coal and 7% oxygen savings, worth around KRW 500 million/year. Investment is approximately KRW 800 million with a source-reported payback of about 1.8 years.
The combined approximately KRW 3.3 billion/year is a consulting potential. Verify using feed composition/throughput, transport conditions, coal/oxygen prices, O₂/CO, product quality and utilization.
| Measure | Assumption / condition | Cost potential |
|---|---|---|
| Feed redistribution | Slag/feed mix approximately 30%; transport cost excluded | KRW 2.8 billion/year |
| O₂/CO control | Coal 1.8%; oxygen 7% expected reductions | KRW 500 million/year |
| Combined | Feed balance plus combustion control | KRW 3.3 billion/year |
| Analyzer/control investment | Two units; reported payback approximately 1.8 years | KRW 800 million investment |
05 · CASE ANALYSIS
Engineering lesson
Feed mass balance and combustion control interact. Preserve product and environmental requirements while evaluating the integrated proposal, and include omitted transport costs before using the historical economics for a new investment.
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