Control of radiant tubes in an indirect-fired strip annealing furnace for improved efficiency

The possibilities for improving the efficiency of an indirect-fired strip annealing furnace with radiant tubes are explored. First, the influence of the fuel/air-ratio on the efficiency is analyzed by means of linearized relationships. Second, the optimum operating range of an individual radiant tube and a new control strategy for the fuel supply are derived. Both analyses are based on the balance model of a single radiant tube. The input data were taken from an experimental measurement campaign of an industrial furnace.