Thermodynamics and mechanism of stabilization and precipitation of petroleum colloids

The influences of different factors on the stability of colloid disperse crude oil systems are investigated by determining the flocculation points. The results are discussed on the base of theory of regular solutions considering the influence of solvation on the kinetics of chemical processes in liquid phases. Analogy to the behavior of polymer solutions was found. Differences result from the micelle structure of colloid particles. The criterion of metastability using nonpolar precipitants is defined by the Flory-Huggins interaction parameter. Using polar precipitants, the polar interactions and the solvation of asphalt require to use the Hansen solubility parameter to interpret the results. The influences of conditions of precipitation and of surfactants are discussed also. (C) 1997 Elsevier Science B.V.