Abstract: A method for acetylene hydrogenation which involves adding a member selected from the group consisting of arsine and phosphine to moderate the activity of acetylene hydrogenation catalysts while maintaining acceptable catalyst activity and avoiding the risk of product quality contamination by the acetylene converter moderator. The acetylene hydrogenation process involves adding arsine at a concentration level within the range of about 1 wppb-3 wppb to the gas, such as ethylene, containing acetylene to prevent temperature runaway during the exothermic acetylene hydrogenation reaction. By controlling the presence of arsine levels to such a relatively low level, temperature runaway during the highly exothermic acetylene hydrogenation reaction is prevented while maintaining acceptable catalyst activity levels for purposes of the acetylene hydrogenation reaction.

Abstract: An improved method for regenerating acetylene hydrogenation catalysts which does not require an oxygenation step is provided. The method may be used to regenerate any acetylene hydrogenation catalyst; however, the method is particularly advantageous when used with a palladium based catalyst which has been used to remove acetylenic contaminants from ethylene.