Methods and apparatuses for producing styrene from ethylbenzene

Abstract

Embodiments of methods and apparatuses for producing styrene are provided. The method comprises the steps of introducing ethylbenzene to a first dehydrogenation reactor containing a first high activity dehydrogenation catalyst at a first predetermined inlet temperature to form a first intermediate effluent stream that comprises styrene, ethylbenzene, and hydrogen. Oxygen is added to the first intermediate effluent stream to form a first oxygenated intermediate effluent stream. The first oxygenated intermediate effluent stream is introduced to a first oxidation-reheat dehydrogenation reactor at a second predetermined inlet temperature of about 530° C. or less to form styrene. The first oxidation-reheat dehydrogenation reactor contains a first oxidation catalyst and a second high activity dehydrogenation catalyst.

1 . An apparatus for producing styrene, the apparatus comprising:
 a first dehydrogenation reactor containing a first high activity dehydrogenation catalyst and configured to receive ethylbenzene at a first predetermined inlet temperature and to form a first intermediate effluent stream that comprises styrene, ethylbenzene, and hydrogen, and configured to be in fluid communication with a first oxygen source; and   a first oxidation-reheat dehydrogenation reactor configured to be in fluid communication with the first oxygen source and the first dehydrogenation reactor and containing a first oxidation catalyst and a second high activity dehydrogenation catalyst, the first oxidation-reheat dehydrogenation reactor configured to receive a first oxygenated intermediate effluent stream from the first oxygen source and the first dehydrogenation reactor at a second predetermined inlet temperature to form styrene.   
     
     
         2 . The apparatus according to  claim 1 , wherein the second high activity dehydrogenation catalyst has a relative activity of about 1.5 or greater. 
     
     
         3 . The apparatus according to  claim 1 , wherein the second high activity dehydrogenation catalyst has a relative activity of about 2 or greater. 
     
     
         4 . The apparatus according to  claim 1 , wherein the first high activity dehydrogenation catalyst has a relative activity of about 1.5 or greater. 
     
     
         5 . The apparatus according to  claim 1 , wherein the first oxidation-reheat dehydrogenation reactor is configured to form a second intermediate effluent stream comprising styrene, ethylbenzene, and hydrogen, and the apparatus further comprises:
 a heat exchanger in fluid communication with the first oxidation-reheat dehydrogenation reactor to receive the second intermediate effluent stream and configured for indirect heating to form a heated second intermediate effluent stream; and   a second dehydrogenation reactor in fluid communication with the heat exchanger to receive the heated second intermediate effluent stream, the second dehydrogenation reactor containing a third high activity dehydrogenation catalyst and configured to operate at conditions effective to form styrene.   
     
     
         6 . The apparatus according to  claim 1 , wherein the first oxidation-reheat dehydrogenation reactor is configured to form a second intermediate effluent stream comprising styrene, ethylbenzene, and hydrogen, and to be in fluid communication with a second oxygen source, the apparatus further comprising:
 a second oxidation-reheat dehydrogenation reactor configured to be in fluid communication with the second oxygen source and the first oxidation-reheat dehydrogenation reactor and containing a second oxidation catalyst and a third high activity dehydrogenation catalyst, the second oxidation-reheat dehydrogenation reactor configured to receive a second oxygenated intermediate effluent stream from the second oxygen source and the first oxidation-reheat dehydrogenation reactor at conditions effective to form styrene.