An apparatus in a radial reactor is described. The apparatus comprises a vertically elongated conduit extending around a circumference of an outer wall of the radial reactor, a vertically oriented cylindrical center pipe in the radial reactor, and a catalyst bed. The conduit comprises an inner face and an outer face and a pair of opposing sides. The inner face has a plurality of slots. The pair of opposing sides have a plurality of slots. There is a riser at a top of the vertically elongated conduit. The catalyst bed is defined by the center pipe and the inner face.