ASPHALT FLOCCULATION AND DEPOSITION IV - DYNAMIC EVOLUTION OF THE HEAVY ORGANIC-COMPOUNDS

The dynamics of formation of asphalt and asphaltene aggregates are stu died. Three different characteristics of the aggregates and their time evolution are compared, namely their precipitation, small-angle scatt ering, and molecular weight distributions. Thin-layer chromatography i s used for the precipitation measurements, and its performance is comp ared with that of the standard IP-143 method. The effects of the preci pitating agent on the structure and the precipitation properties are a lso investigated, as is the time-dependence of the amount of the resin in the solution. It is shown that the short-and long-time properties of the asphalt and asphaltene aggregates are very different, and the e xperimental data that are collected shortly after the aggregates are f ormed can be misleading. Moreover, the time dependence of the amounts of precipitated asphalt and asphaltene aggregates are also very differ ent. A novel scaling approach is proposed for predicting the time-depe ndence of the amount of precipitation, whose predictions are in excell ent agreement with the data. (C) 1997 Elsevier Science Ltd.