Compatibility of Heavy Blends Evaluated by Fouling and Its Relationship With Colloidal Stability

To predict oil compatibility is crucial because incompatibility could cause severe deposition and fouling problems. Therefore, compatibility of heavy oils and blends in different ratios were evaluated by fouling at heat transfer conditions. Thermal resistance and fouling rates were obtained on a fouling loop. Effect of colloidal stability based on asphaltene precipitation and SARA composition on fouling was also discussed. Results showed that different variations of fouling rate versus blending ratio were observed for these blending systems. For oils whose viscosities approach at heat conditions, the lower colloidal stability of blends is the higher fouling rate is. However, for oils with greatly different viscosities, inconsistency was observed between compatibility by the two indicators, which is attributed to remarkable change of flow condition. This indicates that both colloidal stability and flow condition play key roles in fouling. Oil compatibility at heat transfer condition is favored being predicted by fouling instead of correlating with the colloidal stability.