An electric arc furnace produces a continuous stream of off-gas that carries direct information about what's happening inside the melt, carbon monoxide, carbon dioxide, and oxygen concentrations shift in real time as the charge melts, oxidizes, and refines, and the temperature of that gas stream tells its own part of the story about combustion efficiency and energy loss. Most EAF operations still make process decisions primarily from experience and periodic bath sampling, treating off-gas as an emissions compliance measurement rather than a live process control signal, which leaves a significant amount of combustion optimization and energy recovery potential on the table. Reading the off-gas stream continuously changes decisions in real time instead of after the heat is already tapped, and booking a demo shows how that data gets put to work on an operating furnace.
EAF ENERGY · OFF-GAS ANALYSIS · PROCESS CONTROL
Your Furnace Is Already Telling You What It's Doing, Are You Reading It
iFactory analyzes EAF off-gas composition and temperature continuously, turning CO, CO2, and O2 signals into real-time combustion optimization, post-combustion control, and energy recovery decisions.
THE THREE SIGNALS
What CO, CO2, and O2 Each Tell You About the Melt
Each component of the off-gas stream reflects a different aspect of what's happening in the furnace at that moment, and reading them together gives a far more complete picture than any single measurement on its own.
CO
Carbon Monoxide
Rising CO signals incomplete combustion or active decarburization in the bath, a direct indicator of both energy loss potential and refining progress.
CO2
Carbon Dioxide
A rising CO2 to CO ratio indicates more complete combustion, which is the target state for post-combustion energy recovery inside the furnace shell.
O2
Oxygen
Excess oxygen in the off-gas signals over-injection relative to what the melt is actually consuming, a direct and often overlooked source of wasted input.
THE MELT STAGES
How the Off-Gas Signature Shifts Through a Heat
The off-gas composition doesn't stay constant through a heat, it moves through a recognizable pattern tied to the metallurgical stages happening in the bath, and process control decisions should track that pattern rather than applying a fixed setpoint throughout.
Meltdown
CO rises as scrap oxidizes and carbon begins reacting, signaling active energy input demand from the arc.
→
Refining
CO peaks during active decarburization as oxygen lances drive the carbon boil, the highest-value window for post-combustion recovery.
→
Flat Bath
CO tapers as the carbon boil subsides, signaling the melt is approaching tap-ready composition.
→
Tap-Ready
Stable, low CO with elevated CO2 ratio confirms combustion has completed and the heat is ready for final sampling and tap.
See what your off-gas signature actually looks like heat over heat
iFactory can run a diagnostic off-gas analysis against your current process to show where energy is being lost today.
COMBUSTION OPTIMIZATION
Turning Off-Gas Data Into Real-Time Adjustments
Reading off-gas composition only creates value once it drives an actual adjustment to burner, lance, or injection settings while the heat is still running, rather than showing up on a report reviewed after tap.
Oxygen Injection Tuning
Injection rate adjusted against real-time O2 and CO readings to match actual bath demand instead of a fixed program setpoint.
Post-Combustion Control
Post-combustion oxygen lances tuned to maximize CO-to-CO2 conversion during the highest-CO window of the heat for energy recovery.
Burner Sequencing
Burner activation and shutoff timed against the melt stage signature rather than a fixed schedule that doesn't reflect the actual scrap charge.
Off-Gas Temperature Tracking
Temperature trend flags excessive heat loss through the off-gas duct, a direct energy efficiency indicator independent of gas composition.
SAMPLE-BASED VS CONTINUOUS
What Continuous Off-Gas Monitoring Changes
Periodic bath sampling and manual off-gas checks give a snapshot at a single point in the heat, while continuous monitoring tracks the full trend and enables adjustments the sampling approach simply can't support.
| Factor |
Periodic Sampling |
Continuous Off-Gas Monitoring |
| Data Frequency |
A handful of readings per heat |
Constant real-time composition and temperature data |
| Adjustment Timing |
Decisions made after the sample result returns |
Adjustments made as the trend develops within the heat |
| Post-Combustion Tuning |
Set once per program, rarely adjusted per heat |
Tuned dynamically against the live CO peak window |
| Heat-to-Heat Consistency |
Varies with scrap mix and operator judgment |
Standardized against a consistent data-driven signature |
TURNKEY DELIVERY
How iFactory Deploys Off-Gas Analytics on Your Furnace
iFactory installs or integrates with existing off-gas sampling probes and temperature sensors, builds the melt stage signature model against your specific scrap mix and operating practice, and connects real-time recommendations to your process control system.
What Gets Built
Continuous off-gas composition and temperature data pipeline
Melt stage signature model calibrated to your scrap mix and heat profile
Real-time adjustment recommendations for injection and post-combustion control
Heat-by-heat dashboard tracking combustion efficiency and energy recovery
Deployment Timeline
Weeks 1-3: Sensor integration and off-gas data pipeline setup
Weeks 4-7: Melt stage model calibration against live heats
Weeks 8-9: Dashboard go-live and operator training
FREQUENTLY ASKED QUESTIONS
What EAF Operators Ask Before Adopting Continuous Off-Gas Analysis
Do we already have the sensors needed, or does this require new equipment on the furnace?
Many EAF operations already have off-gas sampling probes installed for emissions compliance purposes, and the analytics layer can often integrate directly with that existing sensor infrastructure rather than requiring new hardware. Where sampling frequency or sensor placement isn't sufficient for real-time process control, additional continuous sensors are added at the specific points needed, scoped against what your current setup already provides.
Book a demo to assess your current sensor coverage.
How does the melt stage model adapt to a scrap mix that varies significantly heat to heat?
The model is calibrated against your specific scrap mix patterns and trained on enough historical heats to recognize how the off-gas signature shifts with different charge compositions, rather than assuming a single fixed profile applies to every heat. As new scrap sources or mix ratios are introduced, the model recalibrates against the new pattern, which is a far lighter task than the initial training.
Contact our support team to discuss how variable scrap mix gets handled for your operation.
Can this integrate with our existing furnace control system, or does it operate as a separate tool?
The recommendations are designed to feed directly into your existing process control system wherever an integration point exists, so adjustments to injection rates or post-combustion settings can be actioned automatically or presented to the operator for approval, depending on how much automation your team is comfortable with initially. Most operations start with operator-reviewed recommendations and move toward more automated control as confidence builds.
Book a demo to see the integration options for your control system.
How much energy savings can realistically be expected from this kind of monitoring?
Savings depend heavily on how much room for improvement exists in your current combustion and post-combustion practice, since operations already running tightly tuned processes will see smaller gains than those relying primarily on fixed setpoints and operator experience. The clearest early wins typically come from reducing excess oxygen injection and improving post-combustion timing during the CO peak window of the heat.
Contact our support team to discuss realistic savings expectations for your furnace.
Does this affect our emissions compliance reporting in any way?
The underlying off-gas data used for process optimization is the same category of measurement used for emissions compliance, so the analytics layer typically complements rather than complicates your existing reporting, and in many cases the additional continuous data provides better documentation than periodic compliance sampling alone. Any changes to sensor placement or sampling frequency are reviewed against your compliance requirements before implementation.
Book a demo to discuss how this fits alongside your compliance reporting process.
CO, CO2, O2, AND TEMPERATURE, READ IN REAL TIME
Stop Treating Off-Gas as a Compliance Number and Start Using It to Run the Furnace
iFactory analyzes EAF off-gas composition and temperature continuously, turning it into real-time combustion optimization, post-combustion control, and energy recovery decisions.
