The Conceptual Design And Control Research For Reactive Distillation Columns Based On The Fixed Point Methodology

Reactive distillation, combining reaction with separation in a single process unit, has the potential to develop because of these following advantages: minimizing the production of undesirable byproducts, improving conversion and yield, improving energy efficiency and potentially reducing flowsheet complexity. However, due to the non-linear coupling of reactions and separation, there is a price to pay in the area of increased complexity in design. The higher requirements of steady operation and process control are put forward because of the reactive distillation characteristics.In this paper, a modified fixed point method for the design of reactive distillation column with the multi-component reactive system is developed and illustrated. The method is based on the theory of phase equilibrium, kinetic fixed points and element concept in the reactive distillation map. The proposed graphical presentation takes the effect of temperature on the separation and reaction into account, which helps in extrapolating the design details. After the calculation used by the modified fixed point design method, the detailed design result with four compositions from the chart could be achieved, such as stage numbers, reactive zone, feed location, operating conditions and actual stage compositions. Three example systems are employed to evaluate the modified fixed point methodology proposed. The results show that the methodology is feasibility and computationally efficient even for the complex configurations and multi-component reaction systems.The RD dynamic simulation of Amyl acetate is studied though Aspen Plus. Temperature control method and composition control method are proposed so that the operation result of RD satisfies the producing demand. The feed flow rate and feed composition are regarded as two disturbances to test the control methods. The simulated result show that the feed composition has greater influence on control and the temperature control method is more stable than the composition control method.