EB/SM splitter heat recovery
View Patent ↗Improved methods and related apparatus are disclosed for efficiently recovering the heat of condensation from overhead vapor produced during separation of various components of dehydrogenation reaction effluent, particularly in ethylbenzene-to-styrene operations, by the use of at least a compressor to facilitate azeotropic vaporization of an ethylbenzene and water mixture within a preferred range of pressure/temperature conditions so as to minimize undesired polymerization reactions.
1. In an apparatus for manufacturing styrene by dehydrogenation of ethylbenzene in the presence of steam at elevated temperatures comprising: (a) a reactor system having an inlet and an outlet, and containing a dehydrogenation catalyst, to produce a reactor effluent stream from the reactor system outlet; (b) a fractionation column downstream from the reactor system outlet for processing a first portion of the reactor effluent stream to produce a fractionation overhead stream; (c) a condenser/vaporizer for condensing at least a portion of the fractionation overhead stream by vaporizing ethylbenzene reactor feed; and (d) a conduit for passing the vaporized ethylbenzene reactor feed from the condenser/vaporizer to the reactor system inlet; the improvement comprising: at least a compressor for compressing vapor passing between the fractionation column and the condenser, for compressing vapor passing between the condenser/vaporizer and the reaction system inlet, or both.
2. An apparatus according to claim 1 wherein a compressor is located in-line between the fractionation column and the condenser/vaporizer.
3. An apparatus according to claim 1 wherein a compressor is located in-line between the condenser/vaporizer and the reaction system inlet.
4. An apparatus according to claim 1 wherein a first compressor is located in-line between the fractionation column and the condenser/vaporizer and a second compressor is located in-line between the condenser/vaporizer and the reaction system inlet.
5. An apparatus according to claim 1 wherein said fractionation overhead stream consists essentially of ethylbenzene.
6. An apparatus according to claim 1 further wherein the ethylbenzene reactor feed used in condensing the fractionation overhead stream includes a second portion of the reactor effluent stream.
7. An apparatus according to claim 1 further wherein the ethylbenzene reactor feed used in condensing the fractionation overhead stream includes a recycled portion of the condensed fractionation overhead stream following additional downstream processing.
8. An apparatus according to claim 1 further wherein the ethylbenzene reactor feed used in condensing the fractionation overhead stream includes a second portion of the reactor effluent stream and a recycled portion of the condensed fractionation overhead stream following additional downstream processing.