Bifurcation and Stability Analysis of an Ethylene Oxide Reactor System

Abstract

In this work, an open-loop and closed-loop nonlinear stability analysis of an industrial ethylene oxide reactor is performed. The simulator, which consists of a gas−gas heat exchanger, a multitubular fixed-bed reactor, a steam generator, and a separation system, was benchmarked with data from an industrial ethylene oxide reactor system. A two-dimensional heterogeneous model was developed for the multitubular fixed-bed reactor. The steady-state operability problem (open-loop bifurcation) was addressed by using nonlinear bifurcation techniques. The stable control regions of the ethylene oxide reactor system were developed as a function of operating temperature, catalyst activity, controller tuning, and disturbance direction and magnitude. A reactor runaway event was simulated, from which it is shown that eliminating the oxygen in the feed to the reactor can be used to prevent reactor runaway.