Blast furnace process measurement at Dofasco

Operation at lower fuel rates requires accurate and reliable measurement of several key process variables. In the early eighties, off-line analysis of Dofasco's operation using a two stage heat and mass balance determined that measurement capability was not adequate for the challenge of a low fuel rate operation. To establish a project plan for obtaining a more efficient operation, a sensitivity analysis of the heat and mass balance was conducted. The results of this analysis enabled Dofasco to target several key parameters for sensor technology improvement. The sensors served two basic functions, thermal control and process monitoring. To optimize capital expenditure, sensors that had a direct impact on process control were upgraded first. These sensors were: Oil Flow, Wind Flow, Charged Weights, Hot Blast Temperature, and Coke Moisture. Following this work, the major process monitoring measurements that were improved included: Top Gap Analysis, Cold Blast Humidity, and Hot Metal Temperature. This paper summarizes the work done to improve these sensors, the system in place to monitor their performance, and the application of these systems for the successful operation of the blast furnace.