Study On Optimal Anti-surge Control For Blast Furnace Blowers

Blowers are important power equipments in the blast furnace process. The daily production of blast furnace is affected by the working condition of blowers directly. Surge is the instability of blowers. Anti-surge function is essential in control systems of blowers to guarantee the safe operation of blast furnace as well as blowers themselves. The aim of this thesis is to seek an optimal anti-surge control scheme, which can expand the operation range of blowers and guarantee the stability of blowers running at higher efficiency points. The main works are listed as follows:1. A surge avoidance scheme is designed on consideration of the steady-state and dynamic characteristics of blowers. Based on the model of Greitzer, a control law is derived with its stability proved by Lyapunov Theorem. Simulations on MATLAB*/SIMULINK*platform show that the proposed control scheme can avoid surge effectively.2. Based on a variable speed compressor model, two active surge control schemes are designed using the fuzzy control principle and the backstepping method respectively. Simulation results show that both of the control schemes can suppress surge effectively. The pressure rise can be increased and the flow region can be enlarged then, combined with the operations of blast furnace blowers.3. An anti-surge control system with switching mechanism is designed, which combines surge avoidance with active surge control to achieve the goal of both efficiency and safety. The feasibility of this control scheme is verified by simulation results.