A laser-based sensor for measurement of off-gas composition and temperature in basic oxygen steelmaking

We are developing an optical sensor for process control in basic oxygen ste elmaking. The sensor measures gas temperature and relative CO/CO2 concentra tion ratios through the furnace off-gas during oxygen blowing. In the curre nt configuration, the laser beam is transmitted through the process off-gas directly above the furnace lip and below the exhaust hood, and is being te sted at Bethlehem Steel's Sparrows Point Division, Baltimore, MD. Rapid ana lysis of the detected laser radiation provides the input for real-time cont rol of steelmaking processes. Dynamic gas composition and temperature infor mation provided by this technique are being evaluated for optimizing variab les such as lance height, oxygen flow, post-combustion control, and predict ion of final-turndown bath temperature and carbon content. The noninvasive nature of the optical sensor renders it robust, relatively maintenance-free , and useful for characterizing off-gas streams in general. Additional appl ications of the method are process control for electric furnace and bottom- blown oxygen steel-making processes.