Patent FR-2898517-A1 (FR)
Title: Exchanging reactor to carry out steam reforming reactions, comprises an enclosure, a distribution unit to distribute a charge through a fixed-bed catalytic zone, and a collection unit to collect an effluent from the catalytic zone
Inventor: BERTHOLIN STEPHANE
IPC: C01B3/36
Filed: 2006-03-17
Abstract: The exchanging reactor (1) to carry out steam reforming reactions, comprises an enclosure (2), a distribution unit to distribute a charge through a fixed-bed catalytic zone (10), a collection unit to collect an effluent from the catalytic zone, and a heating unit of the catalytic zone. The collection unit comprises pipes crossing through the catalytic zone. The heating unit of the catalytic zone comprises a combustion zone (13) placed near the catalytic zone, and a supply unit of the combustion zone having oxidizing and fuel gas mixture. The exchanging reactor (1) to carry out steam reforming reactions, comprises an enclosure (2), a distribution unit to distribute a charge through a fixed-bed catalytic zone (10), a collection unit to collect an effluent from the catalytic zone, and a heating unit of the catalytic zone. The collection unit comprises pipes crossing through the catalytic zone. The heating unit of the catalytic zone comprises a combustion zone (13) placed near the catalytic zone, a supply unit of the combustion zone having oxidizing and fuel gas mixture, an evacuation unit of an effluent gas resulting from combustion, and a recirculation tube of the gas effluent. The distribution unit comprises a perforated lower tubular plate (4) in which perforations are prolonged by tubular elements called charge tubes. The catalytic zone comprises a lower inert zone placed on the lower tubular plate in which the inert zone has a thickness corresponding to a length of the charge tubes. The pipes are useful to collect the effluents resulting from the catalytic zone, and are arranged between a collection chamber, which is placed downstream from the catalytic zone and the evacuation units of the effluents. The pipes cross the lower tubular plate in an internal space of the charge tubes in which the pipes are distributed in the catalytic zone and inserted between the heating unit. The heating unit is contained in sheaths, which are partly immersed in the catalytic zone. The sheats are opened in one end and closed in other end. The open end of the sheath is fixed at an upper tubular plate, which is delimiting the collection chamber situated at the top of the catalytic zone. The pipes and sheaths comprise wings on an external wall of the pipes to increase contact surface of the catalytic zone. The heating unit is constituted by the coaxial parts having a supply tube in oxidizing gas mixture, which is emerging in the sheath at the upper level of the catalytic zone and at a bottom of the sheaths, a fuel distribution unit called fuel tube connected to one end of a fuel supply unit and placed inside the supply tube of oxidizing gas mixture, and an oxidation catalyst disposed inside and on a portion of the supply tube of oxidizing gas mixture and downstream of the fuel distribution tube. The recirculation tube is placed in the sheath downstream of the combustion zone. The fuel supply unit is placed inside the supply tube of oxidizing gas mixture, and is prolonged until the bottom of the sheaths. The fuel tube comprises a portion of porous wall. The supply tube of oxidizing gas mixture is filled all along its height and upto the upper end of the catalytic zone of the oxidation catalyst. A coolant is injected into the collection chamber of the effluent resulting from catalytic zone. A perforated upper tubular plate is made up of double wall to allow the circulation of a coolant in the internal space of the charge tubes. An independent claim is included for a method to carry out an endothermic reaction in a fixed-bed catalytic zone.