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US 7,094,939 B1Granted
Styrene process with recycle from dehydrogenation zone
AssigneeUop LLC
InventorJohn J. Jeanneret
Life of this patent
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Abstract
A styrene process is disclosed that uses a dehydrogenation reactor and a transalkylation reactor and in which a significant portion of the benzene, the inhibitors, or both, recovered from the dehydrogenation reactor passes to the transalkylation reactor. The process disclosed herein can also use an alkylation reactor and can increase the run length of the alkylation catalyst.
Claims11
A process for producing styrene comprising:
- a) passing ethylene and a first portion of a first recycle stream comprising benzene to an alkylation reactor containing zeolitic alkylation catalyst to alkylate benzene with ethylene and form ethylbenzene and a polyethylbenzene, and withdrawing from the alkylation reactor an alkylation effluent stream comprising benzene, ethylbenzene, and the polyethylbenzene;
- b) passing at least a portion of the alkylation effluent stream to an alkylation/transalkylation separation section, and withdrawing from the alkylation/transalkylation separation section the first recycle stream comprising benzene, an ethylbenzene stream comprising ethylbenzene, and a polyethylbenzene stream comprising the polyethylbenzene;
- c) passing a second portion of the first recycle stream and at least a portion of the polyethylbenzene stream to a transalkylation reactor containing a zeolitic transalkylation catalyst to transalkylate benzene with the polyethylbenzene and form ethylbenzene, and withdrawing from the transalkylation reactor a transalkylation effluent stream comprising benzene and ethylbenzene;
- d) passing at least a portion of the transalkylation effluent stream to the alkylation/transalkylation separation section;
- e) passing at least a portion of the ethylbenzene stream to a dehydrogenation reactor to dehydrogenate ethylbenzene and form styrene, and withdrawing from the dehydrogenation reactor a dehydrogenation effluent stream comprising styrene and benzene;
- f) passing at least a portion of the dehydrogenation effluent stream to a dehydrogenation separation section, and withdrawing from the dehydrogenation separation section a second recycle stream comprising benzene;
- g) extending the run length of the zeolitic alkylation catalyst by passing at least 33% of the second recycle stream to the transalkylation reactor;
- and
- h) recovering styrene from the dehydrogenation separation section.
6 more elements
Dependencies are inferred from the claim text.