Temperature control of ethylene to butene-1 dimerization reactor

Dimerization reactions of ethylene to butene-l which take place in a contin uously stirred tank reactor with recycle suffer from serious temperature ru naway. Therefore, it is essential to control the dimerization reactor tempe rature to secure safe plant operation and to deliver good quality product. It is also desirable to maintain optimal operation of high ethylene convers ion and desired butene-l yield in the face of plant upsets. The objective o f this paper is, thus, to study the simulated implementation of standard pr oportional-integral (PI) control and linear model predictive control (MPC) for temperature stabilization of such a reactor to maintain favorable ethyl ene conversion and butene-l yield conditions. The mathematical model used i n the simulations is developed by the author's research group (Trabzoni, 19 98). The simulation results revealed the possibility of stabilizing such a reactor by both control algorithms. However, careful tuning of the paramete rs of these controllers is necessary, without which very aggressive or even unstable closed-loop performance will be obtained.