Apparatuses and methods for cracking hydrocarbons

Abstract

Methods and apparatuses are provided for cracking a hydrocarbon. The method includes contacting a hydrocarbon feed stream with a cracking catalyst at cracking conditions to produce a reactor effluent and a spent catalyst. The spent catalyst is transferred to a regenerator, where it is regenerated by contact with an oxygen supply gas at regeneration conditions to produce a regenerated catalyst. The regenerated catalyst is fluidized for catalyst movement with a replacement gas having less than 1 mass percent oxygen gas

1 . A method of cracking hydrocarbons, the method comprising the steps of:
 contacting a hydrocarbon feed stream with a cracking catalyst at cracking conditions in a reactor to produce a reactor effluent and a spent catalyst;   transferring the spent catalyst from the reactor to a regenerator;   regenerating the spent catalyst in the regenerator to produce regenerated catalyst by contacting the spent catalyst with an oxygen supply gas at regeneration conditions; and   fluidizing the regenerated catalyst in the regenerator with a replacement gas for catalyst movement, wherein the replacement gas comprises less than 1 mass percent oxygen gas.   
     
     
         2 . The method of  claim 1  wherein fluidizing the regenerated catalyst further comprises fluidizing the regenerated catalyst with the replacement gas for catalyst movement, wherein the replacement gas comprises more than 95 mass percent steam. 
     
     
         3 . The method of  claim 1  wherein fluidizing the regenerated catalyst further comprises fluidizing the regenerated catalyst with the replacement gas for catalyst movement, wherein the replacement gas comprises more than 95 mass percent nitrogen. 
     
     
         4 . The method of  claim 1  wherein fluidizing the regenerated catalyst further comprises fluidizing the regenerated catalyst with the replacement gas for catalyst movement, wherein the replacement gas comprises a mixture of steam and nitrogen, and wherein the mixture of steam and nitrogen comprises more than 95 mass percent steam and nitrogen. 
     
     
         5 . The method of  claim 1  wherein fluidizing the regenerated catalyst further comprises:
 cooling the regenerated catalyst in a catalyst cooler, wherein the replacement gas fluidizes the regenerated catalyst within the catalyst cooler. 
 
     
     
         6 . The method of  claim 1  further comprising:
 transferring the regenerated catalyst from the regenerator to the reactor in a regenerated catalyst transfer line; and 
 fluidizing the regenerated catalyst in the regenerated catalyst transfer line with the replacement gas. 
 
     
     
         7 . The method of  claim 6  further comprising:
 collecting the regenerated catalyst in a regenerator dense bed prior to transferring the regenerated catalyst from the regenerator to the reactor; and 
 fluidizing the regenerated catalyst in the regenerator dense bed with the replacement gas. 
 
     
     
         8 . The method of  claim 1  wherein regenerating the spent catalyst further comprises producing a combustion gas, the method further comprising:
 stripping the combustion gas from the regenerated catalyst by passing the replacement gas through the regenerated catalyst. 
 
     
     
         9 . The method of  claim 8  further comprising:
 venting the combustion gas from the regenerator in a combustion gas vent line. 
 
     
     
         10 . The method of  claim 1  wherein contacting the hydrocarbon feed stream with the cracking catalyst further comprises contacting the hydrocarbon feed stream with the cracking catalyst wherein the hydrocarbon feed stream comprises petroleum hydrocarbons. 
     
     
         11 . A method of cracking hydrocarbons, the method comprising the steps of:
 combusting coke from a spent catalyst to produce a regenerated catalyst and a combustion gas by contacting the spent catalyst with an oxygen supply gas at regeneration conditions;   stripping the combustion gas from the regenerated catalyst by passing a replacement gas through the regenerated catalyst, wherein the replacement gas comprises less than 1 mass percent oxygen gas; and   cracking the hydrocarbons by combining the hydrocarbons with the regenerated catalyst at cracking conditions to produce the spent catalyst.   
     
     
         12 . The method of  claim 11  wherein stripping the combustion gas from the regenerated catalyst further comprises:
 collecting the regenerated catalyst in a regenerator dense bed; and 
 fluidizing the regenerated catalyst in the regenerator dense bed with the replacement gas. 
 
     
     
         13 . The method of  claim 11  wherein stripping the combustion gas from the regenerated catalyst further comprises stripping the combustion gas from the regenerated catalyst by passing the replacement gas through the regenerated catalyst, wherein the replacement gas comprises more than 95 mass percent steam. 
     
     
         14 . The method of  claim 11  wherein stripping the combustion gas from the regenerated catalyst further comprises stripping the combustion gas from the regenerated catalyst by passing the replacement gas through the regenerated catalyst, wherein the replacement gas comprises more than 95 mass percent nitrogen. 
     
     
         15 . The method of  claim 11  wherein stripping the combustion gas from the regenerated catalyst further comprises stripping the combustion gas from the regenerated catalyst by passing the replacement gas through the regenerated catalyst, wherein the replacement gas comprises a mixture of steam and nitrogen, and wherein the mixture of steam and nitrogen comprises more than 95 mass percent steam and nitrogen. 
     
     
         16 . The method of  claim 11  further comprising:
 cooling the regenerated catalyst in a catalyst cooler prior to cracking the hydrocarbons by combining the hydrocarbons with the regenerated catalyst, wherein the replacement gas fluidizes the regenerated catalyst within the catalyst cooler. 
 
     
     
         17 . The method of  claim 11  further comprising:
 transferring the regenerated catalyst from a regenerator to a reactor in a regenerated catalyst transfer line; and 
 fluidizing the regenerated catalyst in the regenerated catalyst transfer line with the replacement gas. 
 
     
     
         18 . The method of  claim 11  wherein cracking the hydrocarbons by combining the hydrocarbons with the regenerated catalyst further comprises cracking the hydrocarbons by combining the hydrocarbons with the regenerated catalyst wherein the hydrocarbons comprise petroleum hydrocarbons. 
     
     
         19 . The method of  claim 11  further comprising:
 venting the combustion gas from a regenerator in a combustion gas vent line. 
 
     
     
         20 . An apparatus for cracking hydrocarbons comprising:
 a reactor;   a regenerator;   a spent catalyst transfer line configured to transfer a spent catalyst from the reactor to the regenerator;   an oxygen supply gas inlet coupled to the regenerator, wherein the oxygen supply gas inlet is configured to provide an oxygen supply gas to convert the spent catalyst into a regenerated catalyst, and to transfer the regenerated catalyst into a regenerator separator area of the regenerator; and   a fluidizing gas inlet coupled to the regenerator, wherein the fluidizing gas inlet is configured to provide a fluidizing gas different than the oxygen supply gas to the regenerator separator area.