A system for discharging dry solids into high pressure environments is disclosed. The system includes a hopper, a feeder device coupled to the hopper, and a discharge device disposed downstream relative to the feeder device. The feeder device includes a rotatable casing including a plurality of pockets, a stationary core disposed within the rotatable casing, and a plurality of valves. Each pocket includes an inlet, an outlet, and a plurality of first through-holes. The stationary core includes a plurality of channels, where each channel includes a plurality of second through-holes. Each valve is disposed at the outlet of a corresponding pocket from the plurality of pockets. The discharge device includes a valve actuator configured to actuate each valve.