Process and apparatus for gas phase exothermic reactions

Abstract

The gas phase exothermic reaction of a feed gas mixture is carried out by providing first and second chambers in fluid communication with one another and each containing a bed of solid heat exchange material and at least one bed of catalyst material, each chamber being selectively operable in cooling and heating modes. The feed gas mixture is introduced into a selected one of the chambers when the selected chamber is in the cooling mode and the other chamber is in the heating mode so that the feed gas mixture flowing through the selected chamber contacts the bed of heat exchange material before contacting the bed of catalyst material, the feed gas mixture being reacted in the catalyst bed to form a gaseous product. The gaseous product is conducted from the selected chamber to the other chamber so that the gaseous product flowing through the other chamber contacts the bed of catalyst material before contacting the bed of heat exchange material. The direction of gas flow through the chambers is periodically reversed so that the first and second chambers alternately operate in the cooling and heating modes, thereby forming between the first and second chambers a hot zone containing the gaseous products. A portion of the gaseous product is discharged from the hot zone so as to withdraw sufficient heat to maintain the reaction in the catalyst bed of the selected chamber at a temperature below a predetermined maximum temperature, while maintaining autothermicity.