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In this article, the inhibition efficiency of imidazoline derivatives with different alkyl chain was investigated from aspect of diffusion using molecular dynamics method. The diffusion coefficient of three corrosive ions in the inhibitor membrane was proposed to evaluate the inhibition efficiency, and three related parameters, fractional free volume of membrane, interaction energy between membrane and particle, mobility of inhibitor membrane, were also discussed to illuminate the diffusion performance of corrosive particles in inhibitor membrane at length. These researches provide one more reasonable theoretical method to evaluate the inhibition efficiency, and may have important significance for the filtration of inhibitor.

Viscosities are important parameters for design and operation of crude pipelines. The heating temperature is the major factor affecting viscosities of waxy crude below the wax appearance temperature. Below the abnormal point, waxy crude exhibits non-Newtonian flow behavior with the viscosity dependent on the shear rate. Both of these make determination of the non-Newtonian viscosities of waxy crude a very time-consuming job. On the basis of the model for predicting non-Newtonian viscosity of waxy crudes as a function of temperature and precipitated wax, an approach to predict non-Newtonian viscosity of waxy crude heated to various temperatures has been developed only based on a few measurements. The accuracy of prediction by this approach has been verified by 468 viscosity data from the Daqing crude heated at various temperatures. The totally average relative deviation between the measured and predicted viscosity is 9.42%.

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