CFD simulation and experimental measurement of droplet deposition and hydrocarbon fouling at high temperatures

Fouling followed by coke formation can be a major problem in bitumen upgrading process equipment such as cyclone separators and scrubbers of fluid Cokers. One of the primary steps in fouling in such cases is deposition of heavy hydrocarbon droplets carried by vapours. This type of fouling should be differentiated with the fouling in the Coker itself due to thermal cracking at higher temperatures. A CFD model is developed to study deposition under such conditions by including the effect of hydrocarbon phase equilibrium. The model was first evaluated against experimental results from the literature for air-droplet mixture at room temperature. Then, the effect of high temperature process conditions similar to those in industrial conditions was compared from modeling and experimental measurements. The model can potentially be applied to optimize design and operating conditions, thereby minimizing deposition fouling under various conditions.

• A CFD model of hydrocarbon deposition showed good agreement with experiments.
• The Stokes number was the key parameter in determining the droplet deposition.
• Stokes number lower than 0.1 by controlling velocity minimizes the deposition rate.