Online measurement and control system development of combustion state for rolling reheating furnace

Reasonable ratio of air to fuel is an important measure to ensure combustion efficiency for rolling reheating furnace, the optimization of which in the real operation is more like art than science. The target of energy saving can be achieved by adjusting air-fuel ratio according to online measured combustion state. However, in most engineering application, only atmosphere in gas flue is detected for control, which cannot reflect the combustion state in furnace actually. In this paper, in order to capture the combustion state inside the reheating furnace online, oxygen analyzers are installed at the exit of combustion gas in each zone. The excess air coefficient of each zone is adjusted based on the oxygen content measured in the corresponding zone. In this way, the accurate control of oxygen content in all zones can be realized, which has significant innovation and reference value for the combustion control of reheating furnace. The experimental results show that the proposed system can decrease the fluctuation of oxygen content and improve the combustion state control obviously, which is with great promise for the combustion efficiency, product quality and the reduction of iron scale loss.