A process for polymerizing polyethylene is disclosed. The process comprises contacting ethylene and at least one comonomer with a catalyst system to produce a polyolefin. The first catalyst and at least a portion of the second catalyst are co-supported to form a commonly-supported catalyst system. The catalyst system is introduced to a line as a dry-feed. The line is coupled with a polymerization reactor. A carrier fluid is added to the line to form a slurry. The slurry is introduced to the polymerization reactor.