Real-time optical diagnostics for the basic oxygen steelmaking process

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

OSTI ID:10139319

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: USDOE, Washington, DC (United States)
• DOE Contract Number: AC04-76DR00789
• OSTI ID: 10139319
• Report Number(s): SAND--93-8409; CONF-9210213--5; ON: DE93009451
• Country of Publication: United States
• Language: English

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