Process and apparatus for preparing ethylbenzene using vapor phase alkylation and liquid phase transalkylation

Abstract

A process for preparing ethylbenzene from benzene and ethylene in which a vapor phase alkylation reactor is combined with a liquid phase transalkylation reactor wherein the xylenes content of the ethylbenzene product is less than 700 wppm. Also disclosed are ethylbenzene processes in which a series-arranged or combined vapor phase alkylation/transalkylation reaction zone is retrofitted to have a vapor phase alkylation reactor and a liquid phase transalkylation reactor, and in which a parallel-arranged vapor phase alkylation reactor and vapor phase transalkylation reactor is retrofitted to have a vapor phase alkylation reactor and liquid phase transalkylation reactor. An apparatus for the practice of the ethylbenzene process of this invention is disclosed.

1 . A process for preparing ethylbenzene, said process comprising the steps of: 
 (a) contacting an alkylation feed which comprised benzene and ethylene in the presence of an alkylation catalyst in an alkylation reaction zone, to generate an alkylation product which comprises ethylbenzene, xylenes, and polyethylbenzene, said alkylation reaction zone is operated under suitable vapor phase alkylation conditions to maintain substantially all of said alkylation feed and said alkylation product in the vapor phase;    (b) separating a polyethylbenzene product from at least a portion of said alkylation product;    (c) contacting a transalkylation feed which comprises said polyethylbenzene product and benzene in the presence of a transalkylation catalyst in a transalkylation reaction zone, to generate a transalkylation product which comprises ethylbenzene and xylenes, said transalkylation reaction zone is operated under suitable liquid phase transalkylation conditions to maintain substantially all of said transalkylation feed and said transalkylation product in the liquid phase;    (d) separating an ethylbenzene product from a crude product stream which comprises said transalkylation product and said remaining portion of said alkylation product; and 
 wherein the xylenes content of said ethylbenzene product is less than about 700 wppm.  
   
     
     
         2 . The process of  claim 1 , wherein the xylenes content of said ethylbenzene product is less than about 600 wppm.  
     
     
         3 . The process of  claim 1 , wherein said alkylation catalyst comprises a solid, crystalline aluminosilicate selected from the group consisting of ZSM-5, ZSM-11, ZSM-12, ZSM-22, ZSM-23, ZSM-35, ZSM-48, ZSM-50 and mixtures thereof.  
     
     
         4 . The process of  claim 1 , wherein said alkylation catalyst comprises ZSM-5.  
     
     
         5 . The process of  claim 4 , wherein said alkylation catalyst comprises ZSM-5 and at least 70 wt. % of said ZSM-5.  
     
     
         6 . The process of  claim 1 , wherein said vapor phase alkylation conditions include a temperature of about 300 to 500° C., a pressure of 100 to 20790 kPa-a (14.7 to 3015 psia), a weight hourly space velocity (WHSV) based on ethylene of about 0.5 to about 10.0 hr. −1 , and a molar ratio of benzene to ethylene of about 1:1 to 30:1.  
     
     
         7 . The process of  claim 1 , wherein said transalkylation catalyst comprises a solid, crystalline aluminosilicate selected from the group consisting of zeolite Beta, zeolite Y, mordenite, TEA-mordenite, MCM-22, PSH-3, SSZ-25, ERB-1, ITQ-1, ITQ-2, ITQ-30, MCM-36, MCM-49, MCM-56 and mixtures thereof.  
     
     
         8 . The process of  claim 1 , wherein said transalkylation catalyst includes zeolite Y, mordenite, or TEA-mordenite.  
     
     
         9 . The process of  claim 1 , wherein said suitable liquid phase transalkylation conditions include a temperature of 100 to 300° C. a pressure of 690 to 4135 kPa-a (100 to 600 psia), a weight hourly space velocity based on polyethylbenzene product (WHSV) of 0.1 to 100 hr −1 , and a weight ratio of benzene to polyethylbenzene product of 0.5:1 to 10:1.  
     
     
         10 . A process for preparing ethylbenzene, said process comprising the steps of: 
 (a) contacting an alkylation feed which comprises benzene and ethylene in the presence of an alkylation catalyst in an alkylation reaction zone, to generate an alkylation product which comprises ethylbenzene, xylenes, and polyethylbenzene, said alkylation reaction zone is operated under suitable vapor phase alkylation conditions to maintain substantially all of said alkylation feed and said alkylation product in the vapor phase, said alkylation catalyst comprises a solid, crystalline aluminosilicate selected from the group consisting of ZSM-5, ZSM-11, ZSM-12, ZSM-22, ZSM-23, ZSM-35, ZSM-48, ZSM-50 and mixtures thereof;    (b) separating a polyethylbenzene product from at least a portion of said alkylation product;    (c) contacting a transalkylation feed which comprises said polyethylbenzene product and benzene in the presence of a transalkylation catalyst in a transalkylation reaction zone, to generate a transalkylation product which comprises ethylbenzene and xylenes, said transalkylation reaction zone is operated under suitable liquid phase transalkylation conditions to maintain substantially all of said transalkylation feed and said transalkylation product in the liquid phase, said transalkylation catalyst comprises a solid, crystalline aluminosilicate selected from the group consisting of zeolite Beta, zeolite Y, mordenite, TEA-mordenite, MCM-22, PSH-3, SSZ-25, ERB-1, ITQ-1, ITQ-2, ITQ-30, MCM-36, MCM-49, MCM-56 and mixtures thereof;    (d) separating an ethylbenzene product from a crude product stream which comprises said transalkylation product and said remaining portion of said alkylation product; 
 wherein the xylenes content of said ethylbenzene product is less than about 700 wppm;  
 wherein said vapor phase alkylation conditions include a temperature of about 300 to 500° C., a pressure of 100 to 20790 kPa-a (14.7 to 3015 psia), a weight hourly space velocity (WHSV) based on ethylene of about 0.5 to about 10.0 hr. −1 , and a molar ratio of benzene to ethylene of about 1:1 to 30:1; and  
   wherein said liquid phase transalkylation conditions include a temperature of 100 to 300° C. a pressure of 690 to 4135 kPa-a (100 to 600 psia), a weight hourly space velocity based on polyethylbenzene product (WHSV) of 0.1 to 100 hr −1 , and a weight ratio of benzene to polyethylbenzene product of 0.5:1 to 10:1.    
     
     
         11 . The process of  claim 10 , wherein the xylenes content of said ethylbenzene product is less than about 600 wppm.  
     
     
         12 . The process of  claim 10 , wherein said alkylation catalyst comprises ZSM-5 and at least 70 wt. % said ZSM-5.  
     
     
         13 . In a process for the production of ethylbenzene which comprises the steps of contacting a benzene feed, an ethylene feed and a polyethylbenzene feed in the presence of an alkylation catalyst in an alkylation reactor, to generate an alkylation product which comprises ethylbenzene and xylenes, said alkylation reactor is operated under suitable vapor phase alkylation conditions to maintain substantially all of said feeds and said alkylation product in the vapor phase, separating from said alkylation product a first ethylbenzene product having a first xylenes content, the improvement comprising the steps of: 
 (a) providing to said process a transalkylation reactor having a transalkylation catalyst;    (b) removing said polyethylbenzene feed from said alkylation reactor and supplying said polyethylbenzene feed to said transalkylation reactor;    (c) contacting said polyethylbenzene feed with benzene in the presence of said transalkylation catalyst in said transalkylation reactor, to generate a transalkylation product which comprises ethylbenzene and xylenes, said transalkylation reactor is operated under suitable liquid phase transalkylation conditions to maintain substantially all of said polyethylbenzene feed, said benzene and said transalkylation product in the liquid phase;    (d) separating said transalkylation product to generate a second ethylbenzene product; and    wherein the sum of the amount of said first ethylbenzene product and the amount of second ethylbenzene product is at least 15 percent greater than the amount of said first ethylbenzene product.    
     
     
         14 . The process of  claim 13 , wherein the xylenes content of said ethylbenzene product is less than about 700 wppm.  
     
     
         15 . The process of  claim 14 , wherein said alkylation catalyst comprises a solid, crystalline aluminosilicate selected from the group consisting of ZSM-5, ZSM-11, ZSM-12, ZSM-22, ZSM-23, ZSM-35, ZSM-48, ZSM-50 and mixtures thereof; and said transalkylation catalyst comprises a solid, crystalline aluminosilicate selected from the group consisting of zeolite Beta, zeolite Y, mordenite, TEA-mordenite, MCM-22, PSH-3, SSZ-25, ERB-1, ITQ-1, ITQ-2, ITQ-30, MCM-36, MCM-49, MCM-56 and mixtures thereof.  
     
     
         16 . The process of  claim 15 , wherein said vapor phase alkylation conditions include a temperature of about 300 to 500° C., a pressure of 100 to 20790 kPa-a (14.7 to 3015 psia), a weight hourly space velocity (WHSV) based on ethylene of about 0.5 to about 10.0 hr. −1 , and a molar ratio of benzene to ethylene of about 1:1 to 30:1; and 
 wherein said liquid phase transalkylation conditions include a temperature of 100 to 300° C. a pressure of 690 to 4135 kPa-a (100 to 600 psia), a weight hourly space velocity based on polyethylbenzene feed (WHSV) of 0.1 to 100 hr −1 , and a weight ratio of benzene to polyethylbenzene feed of 0.5:1 to 10:1.    
     
     
         17 . In a process for the production of ethylbenzene which comprises the steps of contacting an alkylation feed which comprises benzene and ethylene in the presence of an alkylation catalyst in an alkylation reactor, to generate an alkylation product which comprises ethylbenzene, xylenes and polyethylbenzenes, said alkylation reactor operated under suitable vapor phase alkylation conditions to maintain substantially all of said alkylation feed and said alkylation product in the vapor phase, separating a first ethylbenzene product and a polyethylbenzene product from at least a portion of said alkylation product, contacting a transalkylation feed which comprises said polyethylbenzene product and benzene in the presence of a vapor phase transalkylation catalyst in a transalkylation reactor operated under suitable vapor phase transalkylation conditions to maintain substantially all of said transalkylation feed and said transalkylation product in the vapor phase, to generate a first transalkylation product which comprises ethylbenzene and xylenes, separating said first transalkylation product to generate a second ethylbenzene product, the improvement comprising the steps of: 
 (a) removing said vapor phase transalkylation catalyst from said transalkylation reactor;    (b) supplying said transalkylation reactor with a liquid phase transalkylation catalyst;    (c) operating said transalkylation reactor under suitable liquid phase transalkylation conditions to maintain substantially all of said transalkylation feed and said transalkylation product in the liquid phase, to generate a second transalkylation product which comprises ethylbenzene and xylenes;    (d) separating a third ethylbenzene product from said second transalkylation product; and    wherein the sum of the amount of said first ethylbenzene product and the amount of said third ethylbenzene product is at least 15 percent greater than the sum of the amount of said first ethylbenzene product and the amount of said second ethylbenzene product.    
     
     
         18 . The process of  claim 17 , wherein the xylenes content of said ethylbenzene product is less than about 700 wppm.  
     
     
         19 . The process of  claim 17 , wherein said alkylation catalyst comprises a solid, crystalline aluminosilicate selected from the group consisting of ZSM-5, ZSM-11, ZSM-12, ZSM-22, ZSM-23, ZSM-35, ZSM-48, ZSM-50 and mixtures thereof; and said transalkylation catalyst comprises a solid, crystalline aluminosilicate selected from the group consisting of zeolite Beta, zeolite Y, mordenite, TEA-mordenite, MCM-22, PSH-3, SSZ-25, ERB-1, ITQ-1, ITQ-2, ITQ-30, MCM-36, MCM-49, MCM-56 and mixtures thereof.  
     
     
         20 . The process of  claim 17 , wherein said vapor phase alkylation conditions include a temperature of about 300 to 500° C., a pressure of 100 to 20790 kPa-a (14.7 to 3015 psia), a weight hourly space velocity (WHSV) based on ethylene of about 0.5 to about 10.0 hr. −1 , and a molar ratio of benzene to ethylene of about 1:1 to 30:1; 
 wherein said vapor phase transalkylation conditions include a temperature of about 300 to 500° C., a pressure of 100 to 20790 kPa-a (14.7 to 3015 psia), a weight hourly space velocity (WHSV) based on the polyethylbenzenes of about 0.5 to 100 hr. −1 , and a weight ratio of benzene to polyethylbenzene from 1:1 to 10:1; and    wherein said liquid phase transalkylation conditions include a temperature of 100 to 300° C. a pressure of 690 to 4135 kPa-a (100 to 600 psia), a weight hourly space velocity based on polyethylbenzene feed (WHSV) of 0.1 to 100 hr −1 , and a weight ratio of benzene to polyethylbenzene feed of 0.5:1 to 10:1.    
     
     
         21 . An apparatus for the production of ethylbenzene, comprising: 
 (a) an alkylation reactor having at least one alkylation inlet, at least one alkylation reaction zone and at least one alkylation outlet, said alkylation inlet adapted to introduce at least one alkylation feed stream into said alkylation reaction zone, said alkylation feed stream comprising at least ethylene and at least benzene, said alkylation reaction zone having at least one alkylation catalyst and adapted to maintain suitable vapor phase alkylation conditions, wherein at least one alkylation effluent may be produced when said alkylating agent and said alkylatable aromatic compound are contacted in the presence of said alkylation catalyst, said alkylation effluent which comprises said ethylbenzene and polyethylbenzenes, said alkylation outlet adapted to remove said alkylation effluent;    (b) a means for separating said polyethylbenzenes from at least a portion of said alkylation effluent;    (c) a transalkylation reactor having at least one transalkylation inlet, at least one transalkylation reaction zone and at least one transalkylation outlet, said transalkylation inlet adapted to introduce at least one transalkylation feed stream into said transalkylation reaction zone, said transalkylation feed stream which comprises said polyethylbenzene and benzene, said transalkylation reaction zone having a transalkylation catalyst and adapted to maintain suitable liquid phase transalkylation conditions, wherein at least one transalkylation effluent may be produced when said transalkylation feed stream are contacted in the presence of said transalkylation catalyst, said transalkylation effluent which comprises additional ethylbenzene and a reduced amount of polyethylbenzene, said transalkylation outlet adapted to remove said transalkylation effluent;    (d) a means for separating said ethylbenzene product from a crude product stream which comprises said remaining portion of said alkylation effluent and said transalkylation effluent, said ethylbenzene product which comprises ethylbenzene and xylenes; and 
 wherein the xylenes content of said ethylbenzene product is less than about 700 wppm.  
   
     
     
         22 . The apparatus of  claim 21 , wherein said vapor phase alkylation conditions include a temperature of about 300 to 500° C., a pressure of 100 to 20790 kPa-a (14.7 to 3015 psia), a weight hourly space velocity (WHSV) based on ethylene of about 0.5 to about 10.0 hr. −1 , and a molar ratio of benzene to ethylene of about 1:1 to 30:1; and 
 wherein said liquid phase transalkylation conditions include a temperature of 100 to 300° C. a pressure of 690 to 4135 kPa-a (100 to 600 psia), a weight hourly space velocity based on polyethylbenzene feed (WHSV) of 0.1 to 100 hr −1 , and a weight ratio of benzene to polyethylbenzene feed of 0.5:1 to 10:1.