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Guo L.,Tianjin University of Science and Technology | Tan G.,Tianjin University of Science and Technology | Guan B.,Branch of Langfang of Research Institute of Exploration and Development of Chinese Petroleum | Liang L.,Branch of Langfang of Research Institute of Exploration and Development of Chinese Petroleum
Speciality Petrochemicals | Year: 2011

There is much coal powder generated during coal-bed fracturing, which will block off coal-bed fractures and be harmful to the expansion of cracks. Considering coal surface wettability and flow-backing working fluid, coal powder suspending ability of different surfactants is investigated; suitable main agents of coal powder suspending agent are selected and compounded with some additives. The results show that the best ratio of octadecyl trimethyl ammonium chloride to OP-40 to ethanolamine is 1:1:1, the surface tension is 36.2 mN/m, the contact angle between water and coal powder treated with it is 86°, and the suspending percentage reaches 40.02% when the concentration is 0.3 g/L. Source


Dai C.,China University of Petroleum - East China | Du M.,China University of Petroleum - East China | Zhao M.,China University of Petroleum - East China | You Q.,China University of Petroleum - East China | And 3 more authors.
Journal of Physical Chemistry B | Year: 2013

Micelles formed by fluorocarbon surfactant N-(2-hydroxypropyl) perfluorooctane amide in aqueous solution were studied through surface tension, dynamic light scatting (DLS), isothermal titration calorimetry (ITC), and dissipative particle dynamic (DPD) simulations. Through surface tension measurements, the effectiveness of surface tension reduction, the maximum surface excess concentration, and the minimum area occupied per surfactant molecule at the air/water interface were investigated. The critical micelle concentration (cmc) at different temperatures and a series of thermodynamic parameters (ΔGm 0, ΔHm 0, ΔSm 0, ΔGads 0, ΔHmA and ΔCpm0) of micellization were evaluated. The thermodynamic parameters showed that the micelle formation was entropy-driven. The micelle formation was also confirmed by ITC and DLS. In addition, the DPD simulations were conducted to simulate the whole process of micelle formation to make micelle formation better understood. © 2013 American Chemical Society. Source

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