In the petroleum refining process, heavy crude oil is broken into lighter and more valuable products – such as gasoline and olefinic gases – through fluid catalytic cracking (FCC) process. Hot powdered catalysts are mixed with crude oil to heat up the crude oil to above its boiling temperature to break its long chain molecules. This cracking process occurs in the riser unit of the FCC system. BP Refining and Logistics Technology would like to have a numerical model of one of its FCC risers which will be used as a tool to find possible design or operational improvements to the riser.
The reacting multiphase flow inside the riser is modeled using Computational Fluid Dynamics (CFD) technique. The processes simulated in the CFD model include mixing, vaporization, and cracking reactions, which involves the liquid, solid, and gas phases. A hybrid technique is adopted to model the gas phase flow where gas species of interest are divided into two groups – major species and sub-species. Only major species are assumed to have impact on gas flow calculations. Measured data provided by the riser operator are used to validate the CFD model.
A 3D CFD multi-phase and multi-species reacting flow model of the industrial FCC riser was developed. The flow characteristics and reaction details are well predicted, which are validated against plant data. The simulation results are also visualized in three-dimensional environment through Virtual Reality (VR) technology. The CFD model developed will be used by BP Refining and Logistics Technology for riser design or operational improvements in the future.
“With the help of tools like CFD, today’s student can visualize fluid mechanics at a “micro-level”. Historically, engineers solved problems in the field by measuring variables at a couple of different locations, often great distances apart. Then, they would use the available data to draw conclusions about large systems. Thanks to the ability to run complex computer simulations, today’s student can work with individual droplets inside a pipe, instead of streamlines. With this new technology, our engineers can take a look inside a pipe, for example, and examine it at a much closer level to identify corrosion or other emerging issues, just like a doctor can now use MRI technology to better examine a patient in a non-invasive manner.”
Faculty Collaborator: Dr. Chenn Q. Zhou