The top gas leaving a blast furnace is the only real-time report the stack ever files on what happened thirty meters below, where no sensor can physically reach. CO2 ratio, eta-CO, and top pressure are not just emissions numbers — they are a direct readout of how efficiently reducing gas moved through the burden before it escaped. Most plants glance at top gas composition once a shift and move on, missing the minute-to-minute story it is telling about burden distribution and gas channeling. iFactory's AI reads that story continuously and turns it into specific burden and blast corrections. Book a top gas walkthrough to see your own furnace's gas utilization decoded live.
Top Gas Is Talking. Most Control Rooms Aren't Listening in Real Time
AI-decoded top gas composition turns eta-CO, CO2 ratio, and top pressure trends into specific burden and blast corrections — before poor gas utilization shows up as lost fuel rate.
What Top Gas Composition Is Really Measuring
Every molecule of CO2 in the top gas represents reducing gas that did useful chemical work. Every molecule of unreacted CO represents gas that paid for coke and blast air but left the furnace without reducing any ore. Gas utilization efficiency, expressed as eta-CO, is the single cleanest signal of how well the burden is using the energy it was given.
- Low eta-CO with unreacted CO escaping unused in the top gas
- Uneven CO2 ratio across the furnace cross-section
- Central or peripheral gas channeling past the burden
- Fuel rate rising to compensate for wasted reducing potential
- Top temperature spread widening between probes
- High, stable eta-CO across sustained operating periods
- Even CO2 ratio radially confirming balanced gas flow
- Burden distribution tuned to avoid channeling pathways
- Fuel rate tracking at or below the furnace's proven floor
- Tight, symmetric top temperature profile across probes
How AI Turns Top Gas Data Into Operator Action
Raw gas analyzer output means little without context. The model builds that context continuously so a shift engineer sees a recommendation, not just a chart.
Multi-point gas sampling
CO, CO2, H2, and top temperature readings are pulled from every available probe position, not averaged into a single misleading number.
Radial utilization mapping
The model maps eta-CO and CO2 ratio across the furnace radius to identify exactly where gas is channeling versus where it is doing productive reducing work.
Burden correlation
Utilization patterns are correlated against the last several charging cycles, linking poor gas use back to a specific ore or coke layer decision.
Corrective recommendation
The operator receives a specific charging program adjustment rather than a raw chart, closing the loop between what top gas showed and what to do about it.
Typical Top Gas Composition Ranges
Exact targets vary with burden mix and blast practice, but these ranges are common reference points for a well-utilized furnace running standard coke and pellet burden.
See Your Furnace's Gas Utilization Map
iFactory builds a radial gas utilization map from your existing top gas analyzers and cross probes, showing exactly where reducing gas is being wasted today.
What Changes After Gas Utilization Monitoring
Figures reported by ironmaking teams within six months of adopting continuous top gas utilization mapping.
A BF Specialist's View on Reading Top Gas
We used to look at one averaged eta-CO number and call it a day. The moment we saw the radial map, it was obvious we had a peripheral channel that had been open for months, quietly bleeding fuel rate. Nobody could see it in the averaged trend because the center of the furnace was actually running fine — it hid the problem instead of showing it.
Four Reasons Gas Channeling Goes Undetected
Channeling rarely announces itself. It develops gradually and hides behind averaged data until fuel rate or productivity forces someone to look closer.
Single-point gas sampling
Furnaces relying on one averaged top gas reading have no way to see the radial imbalance that a channel actually creates.
Burden program drift
Small, cumulative changes to charging sequence over months open a channel gradually, with no single event to point back to.
Raw material segregation
Fines segregation during stockhouse handling changes burden permeability in ways top gas reveals long before a stave temperature does.
No correlation to charging history
Without a model linking utilization back to specific charges, operators see the symptom in the gas data but not the burden decision that caused it.
Frequently Asked Questions
What is a good eta-CO value to target?
Most modern furnaces running standard pellet and sinter burden target 48 to 52 percent gas utilization efficiency, though the achievable ceiling depends on burden reducibility and furnace geometry. A model trained on your own historical data gives a more accurate target than any single published benchmark.
How many gas sampling points does the model need?
Most modern furnaces already carry multiple cross probes or above-burden gas sampling points sufficient for radial mapping. Book a demo to review what your current probe layout can already support.
Can this detect channeling before it affects fuel rate?
Yes. Radial utilization imbalance typically shows up in the gas data days to weeks before it translates into a measurable fuel rate or productivity impact, which is exactly the window the model is designed to catch.
Does gas utilization data replace stave temperature monitoring?
No, the two are complementary. Stave temperatures confirm wall-side thermal conditions, while top gas utilization confirms how efficiently the burden is using reducing gas volumetrically. Used together they give a fuller picture than either alone.
How long before we see actionable recommendations?
Baseline mapping from historical data typically takes two to four weeks, after which live recommendations begin appearing on the operator interface. Talk to a specialist about your specific probe configuration and rollout timeline.
Decode Your Furnace's Top Gas Signal
Book a 30-minute scoping call and bring your last month of top gas analyzer data. iFactory shows exactly where gas utilization is being lost across the furnace radius.
