Modelling and Simulation of an Industrial Fluid Catalytic Cracking Unit

To meet ever-changing market dynamics, industrial processes must adapt to new structures of the market demand and environmental restrictions. Using the model provided by Aspen HYSYS and adjusting the kinetic parameters, we aimed to simulate the functioning of an industrial plant as such to obtain results as close as possible to the values observed during operation. The adjusted model allows optimization of the industrial plant operation by extending the range of feeds or catalysts, and also by changing the plant geometry leading to higher yields of desired reaction products, which allows maximization of plant profitability. Fluid catalytic cracking (FCC) is a versatile and often profitable unit of any modern refinery, which is used to convert heavy distillates and residual raw materials in lighter and more valuable products. The FCC unit has the greatest contribution to the production of the gasoline pool, but is also a significant provider of raw materials for the petrochemical industry, such as light olefins. Thus, the FCC unit has a major contribution to the overall profitability of the refinery (1). To meet the ever changing requirements of the market, the plant operators often have to make adjustments in the operation parameters of industrial plants in order to improve yields and increase efficiency of the catalytic cracking unit. Major modifications, however, must be taken into account only after a concerted and successful effort that involves understanding the reactions chemistry, feed characteristics and performance of the equipment. In this respect, using a rigorous simulation models is of crucial importance (2). Coupling hydrodynamic and kinetic models allow calculating, more or less detailed, the performance of an industrial plant. Modelling is therefore important to assess the main limiting phenomena and offer the opportunity to optimize reactor performance by adjusting reactor design and operating conditions so as to limit the steps to maximize the performance of the reactor. Independent on the level of detail involved in the modeling, it is essential to describe all relevant phenomena that must be accounted for, which is not necessarily an easy task (3).