The document discusses a new optical temperature measurement (OTM) sensor for remotely measuring off-gas temperatures in electric arc furnace steelmaking. The sensor uses a proprietary technique to measure intensity at multiple wavelengths to determine temperature, which is not affected by obstructions or emissivity variations like current sensors. Laboratory and on-site tests showed the sensor measurements matched industrial furnace temperatures closely with high repeatability and accuracy from up to 30 meters away. Benefits included improved process understanding and control without requiring contact or maintenance.

1. New Results to Support Remote Optical
Off-gas Temperature
Measurement for EAF Steelmaking
Vadim Gutnik
Sales Manager
Tenova Goodfellow

2. Outline
• OTM Introduction
• Current Off-gas temperature sensing
technologies
• TGI temperature sensor
• Laboratory Tests
• On site Tests
• Results
• Value to the Plant
• Conclusion

3. Introduction
“When you can measure what you are speaking
about and express it in numbers, you know
something about it.
When you cannot measure it, your knowledge is
meager and unsatisfactory”
Lord Kelvin

4. OTM Introduction
Introduction
• Proprietary non intrusive and passive
technology (patent pending)
• Readings are not affected with < 70% of
field of view obstructed
• Continuous measurement of gas
temperature in dust-bearing hot
industrial processes.
• Remote and in-duct applications

5. OTM features
• Continuous, real-time measurement of gas temperature
• Non-contact sensor may be mounted up to 30m away from target
• Passive sensor has no consumable parts and requires virtually no
maintenance
• System measures dust-bearing gases at temperatures between 600°C
to 2,000°C
• Sensor measurement output and alarms are available via 4-20 mA
and/or Ethernet
• Sensor cabinet is NEMA 4 rated, climate controlled, and suitable for
indoor/ outdoor installation

6. Current OG temperature
sensing technology
• Measures intensity of CO2 emission at 4.2 um
– Calculates Temperature from the intensity
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Single Wavelength Pyrometers

7. Current OG temperature
sensing technology
• Issues:
– Any obstruction of the view (for example dirt on lens) reduces the
intensity measured by the camera and consequently the temperature
– An emissivity is assumed for species of interest (for example CO2)
– Presence of the required species to a certain concentration is
mandatory

8. Current OG temperature
sensing technology
Thermocouples
• Full contact sensor susceptible to aging
• Needs protection when mounting in corrosive, dusty , high temperature
conditions
• The protection shroud introduces additional lag to the readings.
• Since thermocouples are made up of two dissimilar metals, they are
vulnerable to corrosion, which can sometimes be difficult to detect. Any
type of light corrosion can result in a misreading by the thermocouple;
therefore, proper care, calibration and maintenance of thermocouples is
essential.
• Requires regular maintenance, has a limited operational lifetime

9. Tenova OTM
TGI temperature sensor

10. Tenova OTM
• It measures the energy (intensity) emitted by the hot off-gas at several
wavelengths
• Wavelengths have been carefully selected after complete spectrum analysis
was measured and analyzed in different steelmaking facilities

11. Tenova OTM
Benefits:
 Debris on lens do not influence the intensity ratio
 Measurement not affected by emissivity variations
 Remote measurement system
 Electronics for the sensor are placed at a distance from direct heat
 Requires virtually no-maintenance
 Can be used for measurement in all types of extreme conditions

12. Tenova OTM
Temperature readings of the Tenova off-gas sensor compared to the industrial furnace
Laboratory Tests

13. Tenova OTM
0 50 100 150 200 250
-30
-20
-10
0
10
20
30
Time (Min)
Deviation
Deviation in Calculated measurements of temperature.
900 C 1025 C 1175 C750 C
Temperature deviation between sensor and industrial furnace temperature
Excellent repeatability

14. Site installations
Tests on site
For the tests we installed the sensor at multiple plants at the selected location
approximately 20-30m away from furnace with clear line of sight

15. Sensor head location

16. Heat data

17. Subsequent heat data

18. OTM vs TC

19. Benefits
Value to the Plant
• Process understanding
• Off-gas temperature can be used for energy losses calculation
• Process pacing and efficiencies, Process upset
• Fume system control (ie. Quencher water flow or primary/secondary FS
Damper control, Scrubber….)
• Better environmental control, ensuring decomposition of dioxins, CO=>Co2
conversion
• Heat progress

20. Benefits
Final Conclusions:
The key distinguishing features for TGI’s advanced Optical Temperature
sensor include:
• This sensor is more sensitive in lower range temperatures and
equally sensitive in higher ranges, high repeatability and accuracy
• The sensor is manufactured mill rugged, suitable for industrial usage
• It can be used as a remote measuring device and needs no surface
contact. Remote measurement of temperature from a distance of
up to 30 m away has been tested.

21. Advantages
Final Conclusions:
• Temperature readings not affected by dust/dirt accumulation on the
optical lens.
• Good comparison with the earlier installed temperature sensors.
• Good behavior and dynamics during the heat.
• Good reliability of measurements over long periods, high stability
and no temperature drift over time
• Does not need daily calibration.

22. Thank You
Vadim Gutnik
Sales Manger
Tenova Goodfellow Inc
Canada