Abstract: A catalyst loading hopper suitable for positioning in vertical position above a reactor vessel, having an inlet at its upper end, a catalyst outlet at its lower end and a diagonally-disposed baffle extending downwardly across the hopper but terminating short of one of the walls of the hopper and a weir adjustably arranged so as to control the flow of catalysts through the hopper. There is a dust outlet at the top of the hopper, which may be connected to a conduit so as to draw dust away from the upper end of the hopper and a screen at the bottom of the hopper to separate the catalyst from any fines or undersized catalyst particles. The screen feeds into a catalyst outlet which, in turn, feeds into a conduit, which extends into the reactor vessel so as to allow arrangement of the cleaned catalyst pellets in layers in the vessel. A gas nozzle opens in the wall of the hopper and allows dust to be blown from the catalyst pellets and through the dust outlet to be collected in a suitable filter.