Coke Gasification on Catalytically Active Surfaces

Abstract

A method and system for converting hydrocarbons into C 2+ unsaturates is described. The method includes providing a structural member upstream of a reaction zone having a surface of a catalytic material, wherein the catalytic material is rendered catalytically active to promote the reaction of coke and/or coke precursors with hydrogen (H 2 ) and/or an oxidant. Then, the method involves exposing a hydrocarbon stream to the catalytic material, wherein the hydrocarbon stream comprising coke and/or coke precursors react in the presence of the catalytic material to convert at least a portion of the coke and/or coke precursors to vapor products. Finally, the hydrocarbons in the hydrocarbon stream containing vapor products and hydrocarbons are converted in the reaction zone to produce a reactor product having C 2+ unsaturates.

1 . A method of converting hydrocarbons into C 2+  unsaturates comprising:
 providing at least one regenerative reverse flow reactor, the regenerative reverse flow reactor having a reactor zone and at least one structural member upstream of the reaction zone; at least a portion of the inner surface of such member comprising a catalytic material that promotes the reaction of coke and/or coke precursors with hydrogen (H 2 ) and/or an oxidant to form vapor products; 
 exposing a hydrocarbon stream that contains coke and/or coke precursors to the catalytic material in the presence of hydrogen and/or an oxidant and reacting at least a portion of the coke and/or coke precursors to form vapor products; and 
 converting at least a portion of the hydrocarbon stream containing the hydrocarbons and the vapor products in the reaction zone to produce a reactor product having C 2+  unsaturates. 
 
     
     
         2 . The method of  claim 1 , further comprising exposing at least a portion of the reactor product that contains coke and/or coke precursors to at least one structural member downstream of the reaction zone, wherein at least a portion of the surface of such structural member comprises a downstream catalytic material thereon that promotes the reaction of the coke and/or coke precursors with hydrogen and/or an oxidant to form vapor products. 
     
     
         3 . A method of converting hydrocarbons into C 2+  unsaturates comprising:
 converting a hydrocarbon stream in a reaction zone of a regenerative reverse flow reactor to produce a reactor product comprising C 2+  unsaturates and hydrogen (H 2 ); 
 exposing at least a portion of the reactor product to at least a portion of a surface of at least one structural member having the catalytic material thereon that promotes the reaction of coke and/or coke precursors with hydrogen (H 2 ) and/or an oxidant at temperatures greater than 150° C.; and 
 reacting in the presence of the catalytic material at least a portion of the coke and/or coke precursors with the hydrogen (H 2 ) and/or oxidant to convert the coke and/or coke precursors to vapor products. 
 
     
     
         4 . The method of  claim 3 , wherein the at least one structural member further comprises a separator vessel upstream of the regenerative reverse flow reactor. 
     
     
         5 . The method of  claim 3 , further comprising exposing at least a portion of the reactor product that contains coke and/or coke precursors to at least one structural member downstream of the reaction zone, wherein at least a portion of the surface of the structural member comprises a downstream catalytic material that promotes the reaction of the coke and/or coke precursors with hydrogen and/or an oxidant to form vapor products. 
     
     
         6 . The method of  claim 3 , wherein hydrogen (H 2 ) is added in a ratio of hydrogen to carbon (H 2 /C) in the range of 0.1 to 5.0 in the hydrocarbon stream. 
     
     
         7 . The method of  claim 6 , wherein the at least one structural member is one of a process tube downstream of the reaction zone, a removal component, a portion of the reactor bed adjacent the removal component, a process tube in a transfer line exchanger, and any combination thereof. 
     
     
         8 . A method of converting hydrocarbons into C 2+  unsaturates comprising:
 converting a first hydrocarbon stream into a reactor product comprising C 2+  unsaturates and coke in a reaction zone of a regenerative reverse flow reactor having a reactor bed and at least one structural member adjacent to an end of the reactor bed, wherein such structural member comprises one or more of a removal component and an injection component, and wherein at least a portion of the inner surface of such structural member comprises a catalytic material that promotes the reaction of coke with an oxidant; 
 removing a first portion of the reactor product from the reaction zone; 
 exposing a second portion of the of the reactor product to (i) the catalytic material and (ii) an oxidant in a stoichiometric excess amount required to react with the coke; 
 reacting the coke and the oxidant in the presence of the catalytic material to convert at least a portion of the coke to vapor products; 
 exothermically reacting the remaining oxidant with a fuel stream in the reaction zone to produce a combustion product; and 
 removing at least a portion of the combustion product prior to the providing a second hydrocarbon stream to the reaction zone. 
 
     
     
         9 . The method of  claim 8 , further comprising disposing a catalytic material on at least a portion of a surface of the reactor bed adjacent the at least one structural member, wherein the catalytic material promotes the reaction of coke with the oxidant stream at temperatures less than 600° C. 
     
     
         10 . The method of  claim 8 , wherein the at least one structural member comprises a heat exchanger downstream of the regenerative reverse flow reactor for the combustion products. 
     
     
         11 . The method of  claim 8 , wherein the converting step comprises thermally cracking the hydrocarbon stream by exposure to temperatures in the range of 1200° C. to 2200° C. in the reaction zone. 
     
     
         12 . The method of  claim 8 , wherein the at least one structural member comprises a poppet valve, wherein the surface is the portion of the poppet valve continuously exposed to an interior region of the regenerative reverse flow reactor. 
     
     
         13 . The method of  claim 8 , wherein the catalytic material comprises one or more of the elements from Group IVB-VIIIB and Group IA-IVA and oxides, sulfides, nitrides, carbides intermetallic and/or reduced metal species. 
     
     
         14 . The method of  claim 8 , wherein the catalytic material is selected to provide a surface net coke deposition rate of less than 0.1 g/m 2 /hr. 
     
     
         15 . A pyrolysis system comprising:
 a pyrolysis unit having a reaction zone, wherein the pyrolysis unit is configured to convert hydrocarbons into C 2+  unsaturates; and   at least a portion of a surface of at least one structural member upstream of the reaction zone having a catalytic material thereon that promotes the reaction of coke and/or coke precursors with hydrogen (H 2 ) and/or an oxidant, wherein the pyrolysis unit is a regenerative reverse flow reactor, and wherein the at least one structural member comprises one or more of a feed injection component upstream of the regenerative reverse flow reactor, a process tube upstream of the regenerative reverse flow reactor, a poppet valve, wherein the surface is the portion of the poppet valve continuously exposed to the interior region of the regenerative reverse flow reactor, a separator vessel upstream of the regenerative reverse flow reactor, a process tube coupled between the separator vessel and the regenerative reverse flow reactor, and a heat exchanger upstream or downstream of the regenerative reverse flow reactor.   
     
     
         16 . The pyrolysis system of  claim 15 , wherein the at least one structural member is one or more of a process tube downstream of the reaction zone, a removal component, a portion of the reactor bed adjacent the removal component, a process tube in a transfer line exchanger, a poppet valve, wherein the surface is the portion of the poppet valve continuously exposed to the interior region of the regenerative reverse flow reactor. 
     
     
         17 . The pyrolysis system of  claim 15 , wherein the catalytic material comprise one or more elements from Group IVB-VIIIB and Group IA-IVA and oxides, sulfides, nitrides, carbides intermetallic and/or reduced metal species.