Dynamic behavior adjustment of 1, 3-propanediol fermentation process

Multiple steady-state solutions typically exist for nonlinear chemical processes and the stability of various solutions may be different. Stability is a key component of chemical process operability and represents the tolerance for small perturbations in the process, which is related to process benefits and safety. As one of the multiple steady-state solutions, the optimal operating point may be located in the unstable branch. 1, 3-propanediol is an important chemical material, however, the optimal operating point with the highest product concentration is unstable. This paper introduced the washout filter-aided controller which was originally used for electric power system and aircraft to adjust the dynamic behavior of the anaerobic fermentation process. By selecting appropriate controller parameters, eigenvalues of an unstable point near the optimal operating point are reassigned to stabilize the high product concentration parts of the equilibrium manifold including the optimal operating point without affecting the shape of the equilibrium manifold. Finally, simulations of the closed-loop system were used to verify the effectiveness of the proposed method of adjusting dynamic behavior.