Bo Yao
China University of Petroleum, China
Title: Micro/Nano Sized Polysilsesquioxanes Facilitate Pour Point Depressing Activity of Polymeric Pour Point Depressants
Biography
Biography: Bo Yao
Abstract
The polymeric pour point depressants (PPDs) have been widely used in pipelines transportating waxy crude oils. However, the performance of PPDs is still unsatisfactory for many waxy crude oils and is liable to be interfered by reheatment, pump-shearing and rest time. It has been verified that the inorganic nanopartiles could improve the performance of PPDs by modifying the morphology of precipitated wax crystals. However, the inorganic nanopartiles need to be organically modified before use and may perhaps cause some problems in downstream refinery. Polysilsesquioxanes micro/nano particles have both good dispersing ability in organic solvent and good heat/shear resistance. In this paper, the Polysilsesquioxanes micro/nano particles were used to disperse in PPDs matrixes to prepare composite PPDs. The composite PPDs could greatly improve the rheology of waxy crude oils, that is, the pour point, viscosity, yield stress of waxy crude oils decrease greatly after composite PPDs addition. The DSC test showed that the composite PPDs act as nucleats of wax crystals and facilitate wax precipitation. The microscopic images of precipitated wax crystals showed that the addition of composite PPDs favors the formation of large spherical-like wax crystals, the structures of which are very compact. A possible heterogeneous nucleation mechanism was put forward: the composite PPDs particles provide models for the wax molecules to precipitate, thus greatly modify of wax crystal morphology and improve waxy crude oil rheology. In addition, the organo-functional group types of methoxysilanes, size of polysilsesquioxane particles, polarity of polymeric PPD have multiple influences on the pour point depressing performance of the composite PPDs.