a method and apparatus are provided for maintaining polymer particles in readily recoverable , discrete form , and for injecting the particles into a pipeline hydrocarbon by disposing particulate polymer within a storage hopper having a cone bottom and an auger extending upwardly from the bottom , rotating the auger to cause the polymer particles to revolve in the hopper , reversing the rotation of the auger to pass polymer particles downwardly into a mixing chamber below the hopper , the particles passing through a rotary metering valve , or optionally , a bin activator , intermediate storage and rotary metering valve at the upper end of the chamber , simultaneously spraying a liquid such as oil or water tangentially in the chamber optionally agitating the chamber and removing a slurry of particulate polymer and the liquid from the chamber and injecting the slurry into a pipeline hydrocarbon .