Real-time optical diagnostics for the basic oxygen steelmaking process

Conference · Mon Feb 01 04:00:00 EST 1993

OSTI ID:6884756

Ottesen, D K; Hurt, R H; Hardesty, D R

This article deals with the development of real-time optical diagnostic techniques for process control in basic oxygen steelmaking. Results are presented of pilot-scale feasibility experiments conducted in the two-ton basic oxygen furnace (BOF) at Bethlehem Steel Corporation's Homer Research Laboratories. Two line-of-sight optical techniques are being evaluated for determining the concentration and temperature of infrared-active gases in the BOF off-gas. The primary objective is to relate the concentration of these gas-phase species to the carbon content of the molten metal, and thereby provide a real-time indication of the process endpoint. Three cw lasers were used to measure the extent of beam attenuation at three different wavelengths in the particle-laden off-gas. The primary attenuation mechanism appears to be scattering by a dense, sub-micron diameter FeO fume. Initial infrared emission experiments with a Fourier transform infrared spectrometer at 1-cm[sup [minus]1] spectral resolution show partially resolved lines in the P-branch of the fundamental CO ground state and first hot-band transitions; CO[sub 2] bandheads are also clearly observed at 2384 and 2397 cm[sup [minus]1]. A second set of experiments was conducted to test the feasibility of oxygen-lance based fiber-optic imaging/pyrometric sensors for measurements of melt temperature and reaction zone properties. During bottom injection of nitrogen, clearly defined images of the melt/slag surface were obtained using both visible and near-infrared video systems. During oxygen blowing, optical emission from the hot spot was observed to fluctuate widely, with characteristic frequencies in the range of 3--10 Hz. Near the end of the process, the emission is characterized by periodic intensity bursts, interpreted as individual ignition events of duration 10--50 msec. Hot spot temperatures were calculated from the emission at 800 and 950 nm wavelengths using a grey-body assumption.

• Research Organization: Sandia National Labs., Livermore, CA (United States)
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: AC04-76DR00789
• OSTI ID: 6884756
• Report Number(s): SAND-93-8409; CONF-9210213--5; ON: DE93009451
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420200 -- Engineering-- Facilities
Equipment
& Techniques
440600* -- Optical Instrumentation-- (1990-)
47 OTHER INSTRUMENTATION
ALLOYS
CARBON DIOXIDE LASERS
CONTROL
DIAGNOSTIC TECHNIQUES
FABRICATION
GAS LASERS
INDUSTRY
IRON ALLOYS
IRON BASE ALLOYS
LASERS
MELTING
METAL INDUSTRY
OPTICAL SYSTEMS
PHASE TRANSFORMATIONS
PROCESS CONTROL
REAL TIME SYSTEMS
STEELS