POLYOLEFIN DRAG REDUCING AGENTS PRODUCED BY MULTIPLE NON-CRYOGENIC GRINDING STAGES

摘要

Fine particulate polymer drag reducing agents (DRAs) in bi-modal or multi-modal particle size distributions may be produced simply and efficiently without cryogenic temperatures. The grinding or pulverizing of polymer, e.g. non-porous poly(alpha-olefin) suitable for reducing drag in hydrocarbons may be achieved by the use of at least one liquid grinding aid and at least two grinding processors in series. The blades of the stators of the grinders are of different configuration so that granulated polymer fed to the first processor having relatively larger gaps between blades is ground to an intermediate size which is fed to the second processor having relatively smaller gaps between blades which grinds the polymer to a second, smaller size. A non-limiting example of a suitable liquid grinding aid includes a blend of propylene glycol, water and hexanol. Particulate DRA may be produced at a size of 300 microns or less in only two passes.