Xylene isomerization process with sulfidation
A technology for the isomerization of hydrogen sulfide and aromatics, applied in isomerization hydrocarbon production, chemical instruments and methods, catalyst activation/preparation, etc., can solve product storage or sales difficulties, high reaction rate, reaction time, yield loss, etc. question
Inactive Publication Date: 2017-05-10
EXXONMOBIL CHEM PAT INC
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Problems solved by technology
First, it is believed that sulfur in the feed often produces sulfur-containing species in the product, which can affect product quality or make product storage or sale more difficult
Second, sulfur is known to cause permanent deactivation of some catalyst sites, which can lead to lower yields, higher aging rates, and shorter catalyst cycle times
Some conditions, such as reduced hydrocarbon feed rate and / or increased hydrogen concentration, can lead to excessively high reaction rates and / or reaction times
Excessive reaction rates and / or reaction residence times can lead to detrimental yield losses such as ring saturation (i.e., hydrogenation of aromatic rings of the hydrocarbon feed) and subsequent hydrocracking of naphthenes
Method used
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[0032] The isomerization process was carried out at constant residence time and hydrogen partial pressure (after catalyst de-edging) while introducing sulfur over a concentration range. This was repeated at two different average reactor temperatures. Specifically, the reactor was operated at set process conditions during a defined, sequential range of time periods (periods I-XIV) from ~1.5 days to ~8 days. These reaction conditions mimic a suboptimal cycle with no priming hyperactivity. During each cycle, ethylbenzene conversion and ring loss were determined. The aromatics feed stream WHSV is set at 10 hr for all periods I-XIV -1 . Process conditions, ethylbenzene conversion and ring loss for each cycle are disclosed below. Cycle I is the start-up phase where the catalyst is demarginated. Cycle II constitutes "Base Condition #1" and Cycle IX constitutes "Base Condition #2".
[0033] Experiments were performed in a pilot plant equipped with reactor, feed system, effluent ...
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A process is provided for the isomerization of aromatic hydrocarbons including contacting an aromatic hydrocarbon feedstream with a catalyst comprising a hydrogenation metal wherein sulfur is continuously introduced after catalyst start-up for an extended period of time at a concentration of no more than 56 ppm by weight of the aromatic hydrocarbon feedstream.
Description
[0001] Inventors: Chunshe Cao, Rachel M. Cook, Michel Molinier, Robert G. Tinger, Marcus L.H. van Nuland [0002] Cross-references to related applications [0003] This application claims priority to and benefit from U.S. Provisional Application No. 62 / 073,625, filed October 31, 2014, the disclosure of which is incorporated herein by reference. This application is related to concurrently filed U.S. nonprovisional application No. ___________ (U.S. Provisional Application No. 62 / 094117, with Attorney No. 2014EM381 / 2). technical field [0004] The present invention relates to a process for the preparation of xylenes and in particular to a process for the isomerization of xylenes. Background technique [0005] Para-xylene (also "para-xylene" or "PX") is generally considered the most important C8 aromatic isomer and is used as an intermediate or starting point for the various end-use applications mentioned above such as synthetic fibers and bottle plastics raw material. Produc...
Claims
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IPC IPC(8): C07C15/08C07C5/27C07C7/20C07C7/171
CPCC07C5/2732C07C5/277C07C7/171C07C7/20C07C15/08B01J29/10Y02P20/52B01J37/20
Inventor 曹春社R·M·库克M·莫立尼尔R·G·廷格M·L·万奴兰德
Owner EXXONMOBIL CHEM PAT INC