Moving Bed Hydrocarbon Conversion Process

Abstract

Moving bed hydrocarbon conversion processes are provided for contacting a catalyst moving downward through a reaction zone with a hydrocarbon feed, withdrawing the catalyst from the reaction zone and conveying the catalyst to a regeneration zone wherein the catalyst moves downward. The catalyst is withdrawn from the regeneration zone and passed downward to an upper zone of a particle transfer apparatus wherein the transfer of catalyst from the upper zone through a middle zone to a lower zone is regulated by varying the pressure of the middle zone, the flow rate of gas passing through an upper valveless conduit, and a valve in a lower valved conduit. The catalyst from the lower zone of the particle transfer apparatus is conveyed to the reactions zone.

1 . A moving bed hydrocarbon conversion process comprising:
 (a) contacting a catalyst moving downward through a reaction zone with a hydrocarbon feed;   (b) withdrawing the catalyst from the reaction zone;   (c) conveying the catalyst to a regeneration zone wherein the catalyst moves downward through the regeneration zone;   (d) withdrawing the catalyst from the regeneration zone and passing the catalyst downward to an upper zone of a particle transfer apparatus;   (e) transferring the catalyst downward from the upper zone of the particle transfer apparatus to a middle zone of the particle transfer apparatus through an upper valveless conduit of the particle transfer apparatus;   (f) increasing the middle zone pressure;   (g) opening a valve in a lower valved conduit of the particle transfer apparatus;   (h) transferring the catalyst downward from the middle zone to a lower zone of the particle transfer apparatus through the lower valved conduit, and transferring gas from the middle zone upward through the upper valveless conduit into the upper zone of the particle transfer apparatus;   (i) closing the valve in the lower valved conduit;   (j) decreasing the middle zone pressure; and   (k) conveying the catalyst from the lower zone to the reaction zone;   
     wherein a pressure of the lower zone is greater than a pressure of the upper zone. 
   
   
       2 . The process of  claim 1  further comprising: introducing oxygen to the regeneration zone, purging a reaction zone gas from the catalyst with nitrogen prior to the introduction of oxygen, purging oxygen from the catalyst withdrawn from the regeneration zone with nitrogen, and introducing a reducing gas to the catalyst before it is transferred to the middle zone of the particle transfer apparatus. 
   
   
       3 . The process of  claim 2  further comprising reducing the catalyst at a temperature between about 315° C. and about 540° C. at super atmospheric pressure in an upper portion of the reaction zone wherein the catalyst is conveyed to the upper portion of the reaction zone in the reducing gas and the reducing gas comprises hydrogen. 
   
   
       4 . The process of  claim 2  further comprising reducing the catalyst at a temperature between about 315° C. and about 540° C. at super atmospheric pressure in the upper zone of the particle transfer apparatus wherein the reducing gas comprises hydrogen. 
   
   
       5 . The process of  claim 2  wherein the reaction zone gas is purged from the catalyst prior to conveying the catalyst to the regeneration zone. 
   
   
       6 . The process of  claim 1  wherein the regeneration zone comprises: a combustion zone, a halogenation zone, a drying zone, and a cooling zone. 
   
   
       7 . The process of  claim 1  wherein the hydrocarbon conversion process is a reforming process, the hydrocarbon feed comprises naphtha, a reaction zone pressure ranges from about 240 kPa(g) to about 3450 kPa(g), and a regeneration pressure ranges from about 0 kPa(g) to about 345 kPa(g). 
   
   
       8 . The process of  claim 1  wherein the hydrocarbon conversion process is a dehydrocyclodimerization process, the hydrocarbon feed comprises C 2 -C 6  aliphatic hydrocarbons, a reaction zone pressure ranges from about 0 kPa(g) to about 2068 kPa(g), and a regeneration pressure ranges between about 0 kPa(g) and about 103 kPa(g). 
   
   
       9 . The process of  claim 1  wherein the hydrocarbon conversion process is a dehydrogenation process, the hydrocarbon feed comprises a paraffin, a reaction zone pressure ranges between about 0 kPa(g) and about 3500 kPa(g), and a regeneration pressure ranges between about 0 kPa(g) and about 103 kPa(g). 
   
   
       10 . The process of  claim 1  further comprising introducing a gas stream into at least one of the upper zone and the lower zone of the particle transfer apparatus. 
   
   
       11 . The process of  claim 1  further comprising sensing the level of catalyst in the middle zone, and transmitting a signal to initiate step 1 (i) when the catalyst level in the middle zone falls below a low level set point. 
   
   
       12 . The process of  claim 1  wherein the valve in the lower valved conduit is opened when the middle zone pressure is within about 35 kPa of a pressure in the lower zone. 
   
   
       13 . The process of  claim 1  wherein the valve in the lower valved conduit is opened when the middle zone pressure is within about 7 kPa of a pressure in the lower zone. 
   
   
       14 . The process of  claim 1  further comprising determining a differential pressure between the middle zone pressure and a pressure in the lower zone during step 1 (f) and initiating step 1 (g) when the differential pressure reaches a predetermined set point. 
   
   
       15 . The process of  claim 1  further comprising during step 1 (e) forming a continuous mass of particles comprising particles in the upper zone, particles in the upper valveless conduit, and particles in the middle zone. 
   
   
       16 . The process of  claim 1  further comprising introducing a gas stream to the middle zone to increase the middle zone pressure in step 1 (f) and venting gas from the middle zone to the upper zone through the upper valveless conduit in step 1 (j). 
   
   
       17 . The process of  claim 1  further comprising transferring at least a portion of gas from the lower zone to the middle zone through a first gas conduit to increase the middle zone pressure in step 1 (f), and venting gas from the middle zone through a second gas conduit in step 1 (j). 
   
   
       18 . The process of  claim 17  wherein the middle zone is vented through the second gas conduit to the upper zone in step 1 (j). 
   
   
       19 . The process of  claim 1  wherein during step 1 (f) the middle zone pressure is equilibrated with the lower zone pressure, and during step 1 (j) the middle zone pressure is equilibrated with the upper zone pressure. 
   
   
       20 . The process of  claim 1  wherein the pressure in the middle zone is greater than a pressure in the upper zone during at least a portion of step 1 (f).