Optimal Process Control and Operation of an Industrial Heat Integrated Fluid Catalytic Cracking Plant Using Model Predictive Control

Abstract

Abstract Nowadays, the optimal control of a heat integrated industrial plant becomes one of the most important research areas in the chemical industry. There are at least two main reasons why this topic is interesting: first, the reduction of production costs applying the heat integration techniques and second, process optimization through advanced control alternatives, when taking into account the improvement of the plant safety in operation and the increasing of the products quality. It is known that the heat integration destabilizes the whole plant, advanced control being needed to make the plant operational. Due to its complexity, the fluid catalytic cracking (FCC) process is a good candidate to apply heat integration and advanced control techniques. It is well known that the investigation of an entire FCC plant taking into account the complex dynamic behavior in conditions of heat integration has not been studied yet. In this study a real FCC plant from a Romanian refinery was used for simulation and at the same time for the implementation of a model predictive control (MPC) strategy in conditions of a previous retrofitted heat integration plant configuration. The aim of this research is to study the complex dynamic behavior of the heat integrated plant under the effect of the main disturbances and to develop an optimal advanced control scheme for the same heat integrated FCC industrial plant. The implemented MPC strategy focused on the response of the heat integrated process in terms of operation, product quality and cost reduction of the heat integrated plant. To simulate the FCC heat integrated process Aspen HySys software was used. In the simulation, the reactor-regenerator section, the main fractionator and the retrofitted heat exchanger network (used for preheating the feedstock before entering the riser) are included.