Abstract: Processes for carrying out catalytic exothermic and endothermic high-pressure gas reactions with a single-walled pressure vessel or shell containing cross-flow (e.g., radial flow) heat transfer exchangers, a continuous catalytic bed having at least two stages, and means for effecting "cross-over" material flows from "outside" to "inside" (for exothermic reactions) and vice versa (for endothermic reactions), whereby conditions of: maximum gas temperature always being in the core of said vessel or shell, minimal pressure drop, and minimal compression of catalyst particles are achieved, along with significant economic savings in cost of the pressure vessel or shell and catalyst (through extension of catalyst life).

Abstract: Unreacted hydrogen contained in the gaseous effluent from a high pressure hydrogenation process is reduced in pressure, followed by purification of the hydrogen at the lower pressure, and recompression to a high pressure for use in a hydrogenation process. Liquid effluent is also reduced in pressure, hydrogen stripped therefrom, and combined with the recovered hydrogen gas at the lower pressure for purification.