Hydrocarbon dehydrogenation process

Abstract

A hydrocarbon dehydrogenation process in which a hydrocarbon feed, normally a straight run naphtha, comprising acyclic and cyclic paraffins is dehydrogenated at elevated temperature of at least 540° C. with process heat provided at least in part by a solar or nuclear thermal energy source.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application relates and claims priority to U.S. Provisional Patent Application No. 61 / 268,774, filed on Jun. 16, 2009.FIELD OF THE INVENTION[0002]This invention relates to hydrocarbon dehydrogenation processes and more particularly to catalytic naphtha reforming processes.BACKGROUND OF THE INVENTION[0003]Hydrocarbon dehydrogenation processes are important commercially in the petroleum refining and petrochemicals industries for the production of unsaturated hydrocarbons such as olefins and aromatics from saturated or more fully saturated precursors. The most important commercial process utilizing hydrocarbon dehydrogenation is the catalytic reforming process in which straight-run naphthas are converted to more highly aromatic products over a catalyst usually containing platinum as an active component. The products may be either high octane gasolines or petrochemical feedstocks.[0004]The catalytic reforming process is generally regarde...

AI Technical Summary

Benefits of technology

[0013]We now propose that hydrocarbon dehydrogenation processes such as reforming are to be provided with process heat from nuclear and solar thermal energy sources. One of the unique attributes of nuclear and solar thermal technologies is their ability to provide high temperature (800 to 1500° C.) high pressure steam. Heat at these temperatures can be utilized effectively for the highly endothermic high temperature dehydrogenation of acyclic and cyclic paraffins to aromatics. The process occurs may be operated in the absence of catalyst or with reduced amounts of lower cost dehydrogenation catalyst or with a catalyst additive for inhibiting excessive cracking and dealkylation reactions at higher temperature.

[0015]1 use of lower cost dehydrogenation catalysts arising from conducting the dehydrogenation at high process temperatures;

[0019]The present invention therefore provides a hydrocarbon dehydrogenation process in which a hydrocarbon feed, normally a straight run naphtha, comprising acyclic and cyclic paraffins is dehydrogenated at elevated temperature of at least 540° C. with process heat provided at least in part by a solar or nuclear thermal energy source. The process is preferably operated with a co-catalyst or additive which is effective to inhibit cracking reactions including dealkylation reactions at the selected operating temperatures. The use of cheaper catalysts which are less active at conventional reforming temperatures also becomes possible at the higher temperatures enabled by the use of nuclear or solar heat sources.

Problems solved by technology

This reaction involves difficult molecular rearrangements of paraffins to naphthenes.

As the catalyst ages, chloride loss becomes appreciable and, inter alia, contributes to loss of catalyst activity and chloridation during the catalyst cycle becomes necessary to maintain activity.

At higher temperatures catalyst activity and selectivity may become unfavorable as paraffin cracking becomes more significant even though aromatization of naphthenes will be promoted thermodynamically.