Methods and apparatuses for treating a hydrocarbon-containing feed stream (UOP)

CATEGORY: MOLECULAR SIEVES
PATENT
Methods and apparatuses for treating a hydrocarbon-containing feed stream (UOP)
Publication number US20130287642 A1
Publication type Application
Application number US 13/928,856
Publication date Oct 31, 2013
Also published as US20130109901, WO2013062669A1
Inventors
David J. Shecterle, Jayant K. Gorawara, Henry Rastelli
Original Assignee
Uop Llc
Abstract
Embodiments of methods and apparatuses for treating a hydrocarbon-containing feed stream are provided. The method comprises the steps of contacting the hydrocarbon-containing feed stream comprising C4, C5, C6, and/or C7 hydrocarbons, water, and contaminants with a Linde Type A molecular sieve at dehydration conditions effective to remove water and form a dehydrated feed stream. The contaminants comprise oxygenates, sulfur compounds, or combinations thereof. The dehydrated feed stream is contacted with a sodium faujasite molecular sieve having a silica/alumina molar ratio of from about 2 to about 2.5 at absorption conditions effective to remove the contaminants and form a dehydrated contaminant-depleted feed stream.
TECHNICAL FIELD
The present invention relates generally to methods and apparatuses for treating a hydrocarbon-containing feed stream, and more particularly relates to methods and apparatuses for treating a hydrocarbon-containing feed stream including removing water and other contaminants, such as oxygenates and/or sulfur compounds, from the feed stream.
BACKGROUND
The removal of water and other contaminants, such as oxygenates and/or sulfur compounds, from light hydrocarbons is often performed to produce a clean hydrocarbon product. The clean hydrocarbon product can be further treated using catalytic reactions, such as catalytic isomerization, to produce other hydrocarbons, increase octane, improve the product value, and/or the like. In particular, catalysts that are typically used for catalytic isomerization and other catalytic reactions are very sensitive to water, oxygenates, and sulfur compounds, which can cause deactivation of the catalyst, thereby reducing catalyst life, increasing the number of catalyst regenerations, and/or requiring complete replacement of the catalyst.
One conventional process for removing water and other contaminants from light hydrocarbons employs a bed arrangement that contains a relatively large pore molecular sieve as an absorbent material. A light hydrocarbon stream is passed through the bed arrangement and the molecular sieve absorbs much of the water and other contaminants from the stream to produce a clean hydrocarbon product. As the molecular sieve removes the undesirable components from the stream, its surface and pores become saturated with water and to a lesser extent the other contaminants, causing the molecular sieve to become less active. To restore its activity, the molecular sieve is regenerated at higher temperatures to help remove the absorbed water and other contaminants. Although water is readily removed from the molecular sieve during regeneration, the other contaminants tend to remain and react at the higher temperatures to form a gummy residue. The gummy residue steadily builds up during each additional regeneration, plugging the pores and causing premature permanent deactivation of the molecular sieve. Since regeneration at this point is no longer effective to restore activity, the molecular sieve needs to be replaced, which is expensive and time consuming.
Accordingly, it is desirable to provide methods and apparatuses for treating a hydrocarbon-containing feed stream using an absorbent material(s) to remove water and other contaminants to produce a clean hydrocarbon product without causing premature permanent deactivation of the absorbent material(s). Moreover, it is desirable to provide methods and apparatuses for treating a hydrocarbon-containing feed stream to produce a clean hydrocarbon product using an absorbent material(s) that may be frequently regenerated to restore activity without causing a steady buildup of gummy residue on the absorbent material(s). Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background.
BRIEF SUMMARY
Methods and apparatuses for treating a hydrocarbon-containing feed stream are provided herein. In accordance with an exemplary embodiment, a method for treating a hydrocarbon-containing feed stream comprises the steps of contacting the hydrocarbon-containing feed stream comprising C4, C5, C6, and/or C7 hydrocarbons, water, and contaminants with a Linde Type A molecular sieve at dehydration conditions effective to remove water and form a dehydrated feed stream. The contaminants comprise oxygenates, sulfur compounds, or combinations thereof. The dehydrated feed stream is contacted with a sodium faujasite molecular sieve having a silica/alumina molar ratio of from about 2 to about 2.5 at absorption conditions effective to remove the contaminants and form a dehydrated contaminant-depleted feed stream.
In accordance with another exemplary embodiment, a method for treating a hydrocarbon-containing feed stream is provided. The method comprises the steps of introducing the hydrocarbon-containing feed stream comprising C4, C5, C6, and/or C7 hydrocarbons, water, and contaminants to a regenerative dehydration zone that comprises a Linde Type A molecular sieve at dehydration conditions effective to remove water and form a dehydrated feed stream and a spent Linde Type A molecular sieve. The contaminants comprise oxygenates, sulfur compounds, or combinations thereof. The spent Linde Type A molecular sieve is regenerated in the regenerative dehydration zone at regenerative conditions effective to form a regenerated Linde Type A molecular sieve. At least a portion of the dehydrated feed stream is introduced to a guard bed that contains sodium faujasite molecular sieve having a silica/alumina molar ratio of from about 2 to about 2.5 and that is operating at absorption conditions effective to remove the contaminants and form a dehydrated contaminant-depleted feed stream.
In accordance with another exemplary embodiment, an apparatus for treating a hydrocarbon-containing feed stream is provided. The apparatus comprises a first dryer containing a first quantity of Linde Type A molecular sieve. The first dryer is configured to receive the hydrocarbon-containing feed stream comprising C4, C5, C6, and/or C7 hydrocarbons, water, and contaminants and to operate in a first dehydration mode at dehydration conditions effective to remove water and form a dehydrated feed stream and a first quantity of spent Linde Type A molecular sieve. The contaminants comprise oxygenates, sulfur compounds, or combinations thereof. A guard bed contains sodium faujasite molecular sieve having a silica/alumina molar ratio of from about 2 to about 2.5 and is configured to receive at least a portion of the dehydrated feed stream and to operate at absorption conditions effective to remove the contaminants and form a dehydrated contaminant-depleted feed stream.
Free Full Text Source: https://www.google.com/patents/US20130287642?dq=hydrogen+inassignee:uop&hl=en&sa=X&ei=C7rvUo_7FInmyQHx1YCgDw&ved=0CDoQ6AEwATgU