PATENT
United States Patent Application 20120024751
Inventors:
He, Zunqing (San Rafael, CA, US)
Verma, Akshay (Richmond, CA, US)
Zhan, Bi-zeng (Albany, CA, US)
Zhou, Zhen (Emeryville, CA, US)
Application Number: 12/847107
Publication Date: 02/02/2012
Assignee: Chevron U.S.A., Inc.
Abstract:
FIELD
The present disclosure is directed generally to a process for removing nitrogen compounds from a hydrocarbon feed by contacting the feed with an adsorbent material.
BACKGROUND
Environmental regulations increasingly mandate liquid fuels containing very low levels of sulfur and nitrogen species. Hydrotreating is the most often used method for reducing sulfur and nitrogen content in a hydrocarbon feed. In general, harsher hydrotreating process conditions and more advanced catalysts are required to further reduce sulfur from about 20 ppm to less than about 1 ppm because of the concentrated recalcitrant sulfur and nitrogen species to be reduced, including, for instance, 4,6-dimethyl dibenzothiophene, trimethyl dibenzothiophene, methyl, ethyl dibenzothiophene, carbazole and alkyl-substituted carbazole. The harsh hydrotreating conditions in turn result in further hydrocracking of diesel and jet fuel to C1-C4 gas and naphthene products, which may be undesired, as well as undesirably high hydrogen consumption.
It would be desirable to develop a process to reduce nitrogen compounds in a hydrocarbon feed while avoiding the aforementioned problems.
It is known that prior removal of nitrogen compounds from the hydrocarbon feed results in increasing the sulfur removal capacity, since both nitrogen and sulfur compounds target the same adsorption and/or hydrodesulfurization sites on the adsorbent or hydroprocessing catalyst and nitrogen being more polar is preferentially adsorbed.
It would additionally be desirable to develop a process by which refractory nitrogen compounds, such as carbazole and indole and their alkyl substitutes would be removed from liquid fuels, resulting in higher capacity to reduce sulfur by either adsorption or hydrodesulfurization.
SUMMARY
One embodiment relates to a method for removing nitrogen compounds from a hydrocarbon feed by contacting the feed with an adsorbent including an organic heterocyclic salt deposited on a porous support, resulting in a product containing a reduced amount of nitrogen as compared with the feed.
Another embodiment relates to a method for hydroprocessing a hydrocarbon feed in which the feed is contacted with an adsorbent including an organic heterocyclic salt deposited on a support to form an intermediate stream, and the intermediate stream is subsequently contacted with a hydrocracking catalyst.
Another embodiment relates to a method for producing a lube oil in which a hydrocarbon feed is contacted with a hydrocracking catalyst, the hydrocracked feed is separated into at least one light fraction and a base oil fraction, and the base oil fraction is contacted with a bed of isomerization dewaxing catalyst, wherein prior to contacting the feed with the isomerization dewaxing catalyst, the base oil fraction is contacted with an adsorbent including an organic heterocyclic salt deposited on a support.
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