화학공학소재연구정보센터
Fuel, Vol.83, No.7-8, 897-903, 2004
Effect of asphaltenes on the thermal properties of emulsions encountered in oil recovery operations
Fabrication temperature of crude oil and bitumen emulsions was found to produce a very strong impact on dynamic viscosities eta and activation energies of a viscous flow E-act. An anomalous increase of both eta and E-act was observed in emulsions, fabricated at 36 degreesC, while fabrication at 45 degreesC improved the flow properties. The narrow critical range of thermally-induced anomalies extends from approximate to30 to approximate to42 degreesC, as revealed by studies of a matrix crude oil. At room temperature the materials retained a long-term memory of fabrication conditions. We suggest that the anomalous thermal effects are triggered by a structural phase transition in the asphaltene/resin molecular subsystem. Below the wax appearance temperature structurally modified asphaltene particles evidently act as cementing species in extended networks of wax crystals. (C) 2003 Elsevier Ltd. All rights reserved.