Preparation of microencapsulated α-olefin drag reducing polymer used in oil pipeline transportation

Microcapsules containing oil drag-reducing polymer particles were prepared by melting-scattering and condensing of polyethylene wax, in-situ polymerization of urea and formaldehyde, and interfacial polymerization of styrene respectively. The related processes were studied by a molecular dynamics simulation method, and molecular design of microcapsule isolation agent was carried out on the basis of the simulation. The technologies for preparing microencapsulated oil drag-reducing polymer particles were compared and the circulation drag reducing efficiency of the microencapsulated polymer particles was evaluated based on the characterization results and their dissolution properties. Molecular design of a microcapsule isolation agent suggests that α-olefin polymer particles can be stably dispersed in water by using long-chain alkyl sodium salt surfactant which can prevent the agglomeration of α-olefin polymer particles. The results of simulation of the adsorption process shows that the amount of alkyl sodium salt surfactant can directly affect the stability of microencapsulated α-olefin polymer particles. and there must be a minimum critical amount of it. After characterization of the morphology by Scanning Electron Microscopy (SEM) and comparison of the static pressure stability, especially the conditions of reaction and technological control of microcapsules with different shell materials, microencapsulation of α-olefin polymer particles with poly-(urea-formaldehyde) as shell material was selected as the optimum scheme, because it can react under mild conditions and its technological process can be controlled in a large range. The relationship of drag reducing rate and dissolving time of microcapsules showed that the formation of microcapsules did not affect the maximum drag reducing rate, and the drag reducing rate of each sample can reach about 35% along with the dissolving time, i.e. microencapsulation did not affect the drag reducing property of α-olefin polymer.