The precipitation of asphaltenes from crude oils is a major concern for oil production. A generalized geometric population balance model for asphaltene aggregation along with the thermodynamics of asphaltene destabilization are brought into a unified framework. This study focuses on the nano-aggregation of asphaltenes destabilized by the addition of heptane. The destabilization of asphaltenes is dictated by equilibrium thermodynamics and is relatively rapid while the kinetic phenomena associated with the reaction limited flocculation process is slow. The model is in agreement with the experimental data of the the evolution of centrifuged aggregates of varying heptane composition. The flocculation process accelerates with increasing amounts of heptane added to the asphaltenic crude because of the larger quantity of destabilized asphaltene.