Reactor and process for endothermic gas phase reactions on a solid catalyst

Abstract

The invention concerns a reactor for catalytic reforming or for hydrocarbon dehydrogenation, having a cylindrical shape along a vertical axis, an upper head and a lower bottom comprising at least two annular zones centred on the vertical axis, said two annular zones being a zone termed a catalytic zone and a zone termed the exchange zone. Vertical hermetic panels divide the reactor into sectors, said sectors each comprising at least one exchange section and at least one catalytic section, the ensemble of said exchange sections forming the exchange zone and the ensemble of said catalytic sections forming the catalytic zone. The invention also concerns the process employing the reactor of the invention.

1 . A reactor for carrying out an endothermic gas phase reaction, having a cylindrical shape along a vertical axis and comprising:
 at least two annular zones, centred on the vertical axis: a catalytic zone and an exchange zone;   vertical hermetic panels ( 65 ) located along the radii of the cylindrical reactor which divide the reactor into sectors, said sectors each comprising at least one exchange section ( 61 ) and at least one catalytic section ( 62 ), an ensemble of said exchange sections forming the exchange zone ( 204 ) and an ensemble of said catalytic sections forming the catalytic zone ( 202 ).   
     
     
         2 . A reactor according to  claim 1 , in which the catalytic zone then the exchange zone are in succession from the edge towards the centre of the reactor. 
     
     
         3 . A reactor according to  claim 1 , wherein in which at least four annular zones centred on the vertical axis are in succession from the edge towards the centre of the reactor, namely a first zone ( 201 ) termed the supply zone, a second zone ( 202 ) termed the catalytic zone, a third zone ( 203 ) termed the collection zone and a fourth zone ( 204 ) termed the exchange zone. 
     
     
         4 . A reactor according to  claim 1 , wherein the vertical hermetic panels ( 65 ) are fixed along a central cylindrical zone ( 205 ), said sectors each comprising an exchange section ( 61 ), a catalytic section ( 62 ), a supply section ( 161 ) and a collection section ( 162 ), an ensemble of said exchange sections forming the exchange zone ( 204 ), an ensemble of said catalytic sections forming the catalytic zone ( 202 ), an ensemble of said supply sections forming the supply zone ( 201 ) and an ensemble of said collection sectors forming the collection zone ( 203 ). 
     
     
         5 . A reactor according to  claim 1 , comprising at least one pipe ( 163 ) per sector passing through the upper head of the reactor to supply the catalytic sections with catalyst and at least one pipe ( 263 ) per sector passing through the lower bottom of the reactor to evacuate catalyst from the catalytic sections. 
     
     
         6 . A reactor according to  claim 1 , comprising an upper head and a lower bottom and:
 a supply conduit ( 17 ) passing through the upper head of the reactor for supplying a sector, denoted the first sector, with reaction mixture;   an evacuation conduit ( 18 ) passing through the upper head of the reactor for evacuating the reaction mixture from the last sector of the reactor;   a conduit ( 67 ) connecting the collection zone of the last sector to the evacuation conduit ( 18 ) in order to evacuate the reaction mixture.   
     
     
         7 . A reactor according to  claim 6 , comprising:
 an inlet conduit ( 6 ) passing through the lower bottom of the reactor and connected to conduits ( 70 ) leading to tubular chambers ( 71 ), said tubular chambers distributing combustion gas by means of tubular plates ( 69 ) via the bottom of the reactor and into each exchange section;   tubular chambers ( 72 ) for collecting combustion gas from the top of each exchange section, and conduits ( 73 ) provided with expansion bellows ( 74 ) for evacuating the combustion gas towards an outlet conduit ( 7 ) passing through the upper head of the reactor.   
     
     
         8 . A reactor according to  claim 1 , in which each catalytic section comprises two concentric metal screens. 
     
     
         9 . A reactor according to  claim 1 , in which each exchange section comprises tubular exchangers. 
     
     
         10 . A reactor according to  claim 1 , in which each exchange section is constituted by plate exchangers. 
     
     
         11 . A reactor according to  claim 1 , comprising a plurality of exchange sections having identical surface areas. 
     
     
         12 . A reactor according to  claim 1 , comprising a plurality of exchanges wherein surface area of each exchanger increases from the first to the last exchange section. 
     
     
         13 . A reactor according to  claim 1 , having a plurality of catalytic sections having the same dimensions. 
     
     
         14 . A reactor according to one  claim 1 , in which the dimensions of the catalytic sections increase from the first to the last catalytic section. 
     
     
         15 . A reactor according to  claim 4 , comprising a conduit ( 64 ) connecting the collection section of each sector, with the exception of the last sector, to the exchange section of the next sector. 
     
     
         16 . A reactor according to  claim 1 , said vertical hermetic panels ( 65 ) dividing the reactor into 3, 4, 6 or 8 sectors. 
     
     
         17 . A process comprising providing a reactor according to  claim 1  and carrying out a catalytic reforming reaction or a hydrocarbon dehydrogenation reaction in said reactor. 
     
     
         18 . A process for carrying out a catalytic reforming or hydrocarbon dehydrogenation reaction in a reactor according to  claim 15 , in which the reaction mixture enters the reactor via the conduit ( 17 ) then moves from top to bottom in the first exchange section ( 61 ), passes under the first catalytic section ( 62 ) between catalyst down pipes ( 263 ), then passes radially through a first catalytic section ( 62 ), passing from the supply zone ( 201 ) to the collection zone ( 203 ) of the reactor, passes to the exchange section of a second sector via the conduit ( 64 ) then moves in succession and in alternating manner in the next exchange sections and the next catalytic sections. 
     
     
         19 . A process according to  claim 18 , in which the catalyst moves from top to bottom at the same rate in all of the catalytic sections. 
     
     
         20 . A process according to  claim 18 , in which the catalyst moves from top to bottom at a rate which increases from the first to the last catalytic section. 
     
     
         21 . A process according to  claim 17 , wherein pressurized combustion gas heats the reaction mixture by indirect heat exchange. 
     
     
         22 . A process according to  claim 21 , further comprising a process for producing the combustion gas supplying the reactor ( 60 ) via the conduit ( 6 ) includes heating air at atmospheric pressure moving via a line ( 1 ) to an air compressor ( 2 ) then via a line ( 3 ) towards a combustion chamber ( 4 ) in which burning of a fuel gas moving via a line ( 5 ) can heat the combustion gas to a temperature in the range 600° C. to 800° C. 
     
     
         23 . A process according to  claim 21 , further comprising a process for producing the combustion gas supplying the reactor ( 60 ) via the conduit ( 6 ) including heating air at atmospheric pressure moving via a line ( 1 ) towards an air compressor ( 2 ) then via a line ( 3 ) towards a combustion chamber ( 4 ) in which burning of a fuel gas moving via a line ( 5 ) can heat the combustion air which then passes via an expansion turbine ( 12 ) which is on the same shaft as the air compressor and which provides the power necessary for compression, the combustion gas leaving the expansion turbine ( 12 ) being at a pressure in the range 0.2 to 0.45 MPa, and at a temperature in the range 600° C. to 800° C. 
     
     
         24 . A process according to  claim 23 , in which the combustion gas leaving the reactor via the conduit ( 7 ) is re-heated in a combustion chamber ( 8 ) before being sent to a turbo-expander ( 10 ) to produce electricity.