Processes for the reduction of alkylation catalyst deactivation utilizing stacked catalyst bed

Abstract

Alkylation systems and methods of minimizing alkylation catalyst regeneration are discussed herein. The alkylation systems generally include a preliminary alkylation system adapted to receive an input stream including an alkyl aromatic hydrocarbon and contact the input stream with a first preliminary alkylation catalyst disposed therein to form a first output stream. The first preliminary alkylation catalyst generally includes a Y zeolite. The systems further include a first alkylation system adapted to receive the first output stream and contact the first output stream with a first alkylation catalyst disposed therein and an alkylating agent to form a second output stream.

1 . An alkylation system comprising:
 a preliminary alkylation system adapted to receive an input stream and contact the input stream with a first preliminary alkylation catalyst comprising a Y zeolite disposed therein to form a first output stream, wherein the input stream comprises an alkyl aromatic hydrocarbon; and   a first alkylation system adapted to receive the first output stream and contact the first output stream with a first alkylation catalyst disposed therein and an alkylating agent to form a second output stream.   
     
     
         2 . The system of  claim 1 , wherein the preliminary alkylation system further comprises a second preliminary alkylation catalyst. 
     
     
         3 . The system of  claim 2 , wherein the first and second preliminary alkylation catalysts are arranged within the preliminary alkylation system so that the input stream contacts the Y zeolite in proximity to the input stream contacting the first alkylation catalyst. 
     
     
         4 . The system of  claim 1 , wherein the alkyl aromatic hydrocarbon comprises benzene. 
     
     
         5 . The system of  claim 4 , wherein the alkylating agent comprises ethylene and the second output stream comprises ethylbenzene. 
     
     
         6 . The system of  claim 1 , wherein the first output stream comprises about 100 ppb or less of catalyst poisons. 
     
     
         7 . The system of  claim 1 , wherein the first output stream comprises about 50 ppb or less of catalyst poisons. 
     
     
         8 . The system of  claim 1 , wherein the first output stream comprises a second level of catalyst poisons, the input stream comprises a first level of catalyst poisons and the second level is lower than the first level. 
     
     
         9 . The system of  claim 8 , wherein the second level is at least 20% lower than the first level. 
     
     
         10 . The system of  claim 1 , wherein the first alkylation catalyst comprises a cerium promoted zeolite beta catalyst. 
     
     
         11 . An alkylation system comprising:
 a preliminary alkylation system adapted to receive an input stream comprising an alkyl aromatic hydrocarbon and contact the input stream with a first preliminary alkylation catalyst prior to contact with a second preliminary alkylation catalyst to form a first output stream, wherein the second preliminary alkylation catalyst comprises a Y zeolite; and   a first alkylation system adapted to receive the first output stream and contact the first output stream with a first alkylation catalyst disposed therein and an alkylating agent to form a second output stream.   
     
     
         12 . The alkylation system of  claim 11 , wherein the first preliminary alkylation catalyst is selected from MCM-22, MCM-49 and combinations thereof. 
     
     
         13 . The alkylation system of claim  121 , wherein the preliminary alkylation system is adapted to further contact the input stream with the second preliminary alkylation catalyst prior to contact with the first preliminary alkylation catalyst. 
     
     
         14 . The system of  claim 11 , wherein the alkyl aromatic hydrocarbon comprises benzene. 
     
     
         15 . The system of  claim 14 , wherein the alkylating agent comprises ethylene and the second output stream comprises ethylbenzene. 
     
     
         16 . The system of  claim 11 , wherein the first output stream comprises about 100 ppb or less of catalyst poisons. 
     
     
         17 . The system of  claim 11 , wherein the first output stream comprises about 50 ppb or less of catalyst poisons. 
     
     
         18 . The system of  claim 11 , wherein the first alkylation catalyst comprises a cerium promoted zeolite beta catalyst. 
     
     
         19 . A method of minimizing alkylation catalyst regeneration comprising:
 contacting an alkyl aromatic hydrocarbon with a first preliminary alkylation catalyst and then a second preliminary alkylation catalyst comprising a Y zeolite prior to contact with an alkylation catalyst;   substantially continuously contacting the alkyl aromatic hydrocarbon with the alkylation catalyst in the presence of an alkylating agent to form an output stream; and   withdrawing the output stream from the alkylation system over a period of time substantially equal to a life of the alkylation catalyst, wherein the life of the alkylation catalyst is longer than the same alkylation catalyst's life in the absence of contact with the first and second preliminary alkylation catalysts.