Real-time, optical measurement of gas temperature and particle emissivity in a full-scale steelmaking furnace

Abstract

This article summarizes the successful implementation of a novel technique for measuring gas temperature and particle emissivity in real time at the mouth of a full-scale basic oxygen furnace (BOF). Both the technique and the data presented here may be useful to both process-control professionals interested in energy balances and computational fluid dynamic (CFD) modelers seeking in-situ data for their specific radiation heat-transfer submodels and temperature-boundary conditions. A description of the sensor, the retrieval algorithms, and the assumptions associated with each is included. The technique is based on midinfrared-emission spectroscopy. Results from a campaign spanning seven heats at a 168-tonne converter with data points every 2 seconds have been reported. During decarburization, the average off-gas temperature and particle emissivity were 1471 K and 0.55, respectively, for low-carbon heats (aim carbon <0.08 pct), and 1517 K and 0.36, respectively, for high-carbon heats (aim carbon >0.30 pct). Practical issues, validation of the assumptions, and measurement uncertainty are discussed. This technique may be applicable to other metallurgical batch processes in which large columns of high-temperature off-gases containing CO, CO2, and particles are present. © 2009 The Minerals, Metals & Materials Society and ASM International.