Temperature measurement techniques for rolling mill furnaces. Final report

John Niska

Recent advances in sensor technology now provide commercial instrumentation for non-contact average furnace gas temperature measurements, either optically (infrared absorption with TDLAS, or infrared emission with IR pyrometers) or acoustically (acoustic pyrometer). The first two new techniques have been tested in industrial reheating furnace trials. A TDLAS for the simultaneous measurement of the oxygen concentration and gas temperature, sometimes gave good temperature measurements, for example, at SSAB in the first zone (z1) where the temperatures were about 800–1000 °C with a high oxygen concentration (3-5 %). The O₂ TDLAS technique for gas temperature measurements failed in the soaking zone (z5) with low oxygen concentrations and high gas temperatures (<1 % oxygen and 1400 °C).