The evolution of heavy crude oil's asphaltene particle size distribution by elevating temperature

Abstract

Temperature variation during crude production, transportation, and processing gives heavy organic deposition problems. Asphaltene particle size evolution from two Iranian heavy crudes (I and II) in thermal de-asphaltene in the absence of n-alkane by temperature variations from 60°C to 160°C was investigated by dynamic light scattering. Onset and optimum asphaltene dissociation temperatures were specified as characteristic parameters for thermal de-asphaltene. Onset temperatures for crudes and are 100°C and 80°C, respectively. Maximum asphaltene particle size and best filtration rate occurred at 150°C and 120°C for crudes I and II, respectively, suggesting asphaltene optimum isolation temperature. Particle aggregation size decreased from 60°C to onset temperature, increased from onset to optimum temperature and decreased by passing optimum temperature. Size decrease over optimum temperature confirmed partial reversibility of asphaltene dissociation mechanism. Results suggest operating temperature in thermal de-asphaltene approaches between onset and optimum temperatures with maximum yield at optimum temperature, which is crude dependent. [Received: August, 3, 2015; Accepted: November 25, 2015]