PROCESSES FOR IONIC LIQUID CATALYZED UPGRADING OF OXYGENATE CONTAINING HYDROCARBON FEEDSTOCKS

Abstract

Ionic liquid catalyzed hydrocarbon conversion processes for upgrading oxygenate containing olefinic hydrocarbon feedstocks may involve treating an oxygenate containing hydrocarbon stream to provide an olefin enriched hydrocarbon stream, which may be contacted with an ionic liquid catalyst under hydrocarbon conversion conditions to provide a converted hydrocarbon stream containing one or more halogenated components; such components may be removed from the converted hydrocarbon stream to provide one or more dechlorinated hydrocarbon products.

Description

TECHNICAL FIELD

The present invention relates to ionic liquid catalyzed processes for upgrading oxygenate containing hydrocarbon feedstocks.

BACKGROUND

Ionic liquid catalysts may find applications in a range of hydrocarbon conversion processes. An example of an ionic liquid catalyzed hydrocarbon conversion reaction is the alkylation of isoparaffins with olefins (see, e.g., U.S. Pat. No. 7,432,408 to Timken et al.). In contrast, a widely used conventional process for the alkylation of isoparaffins with olefins is catalyzed by sulfuric acid or hydrofluoric acid. Apart from environmental, health and safety concerns related to the use of large volumes of H₂SO₄ or HF, ionic liquid catalyzed hydrocarbon conversion processes offer a number of advantages over conventional processes, including: lower capital expenditure on plants, lower operating expenditure, lower catalyst inventory volume, lower catalyst make-up rate, expansion of usable feeds, and higher product yield.

Many hydrocarbon streams may contain substantial amounts of oxygenates. An “oxygenate” may be defined as any oxygen-containing hydrocarbon compound. Examples of oxygenates include alcohols, carboxylic acids, aldehydes, esters, ketones, and the like. Even relatively trace amounts of some oxygenates may deactivate ionic liquid catalysts. As a result, some potentially useful feedstocks for ionic liquid catalyzed hydrocarbon conversion reactions may have been considered unsuitable due to the presence of oxygenates. Therefore, there is a need for the effective removal of oxygenates in oxygenate containing hydrocarbon streams prior to contacting the hydrocarbon stream with an ionic liquid catalyst.

The presence of a catalyst promoter or co-catalyst with an ionic liquid catalyst may provide an increased level of catalytic activity, for example, as disclosed by U.S. Pat. No. 7,432,408 to Timken et al. Typically, anhydrous HCl or organic chloride may be added as co-catalyst to direct the ionic liquid catalyzed reactions to the desired level of activity and selectivity (see, e.g., U.S. Pat. Nos. 7,495,144 to Elomari, and 7,531,707 to Harris et al.). However, the presence of chloride in the reactor may result in hydrocarbon conversion products having an unacceptably high organic chloride content. As an example, the removal of organic chloride components from liquid fuels may be desirable to prevent the formation of unwanted by-products during combustion (see, for example, U.S. Pat. No. 7,538,256 to Driver et al.). Accordingly, there is a further need for the effective removal of halogenated components from ionic liquid catalyzed hydrocarbon conversion products.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 represents a scheme for an ionic liquid catalyzed hydrocarbon conversion process using an oxygenate containing hydrocarbon feed, according to an embodiment of the present invention; and

FIG. 2 represents a scheme for an olefin enrichment process using an oxygenate containing hydrocarbon feed, according to an aspect of the process of FIG. 1.

SUMMARY

The present invention provides hydrocarbon conversion processes involving the treatment of oxygenate containing hydrocarbon streams to provide an olefin enriched hydrocarbon stream, which may be contacted with an ionic liquid catalyst to provide a converted hydrocarbon stream comprising organic halide (e.g., chloride) components. The converted hydrocarbon stream may be treated in a dechlorination zone to remove organic chloride from the converted hydrocarbon stream, e.g., by treatment with hot caustic, an adsorbent, or a hydrodechlorination catalyst, to provide a dechlorinated hydrocarbon product.

According to one aspect of the present invention there is provided an ionic liquid catalyzed hydrocarbon conversion process comprising treating an oxygenate containing hydrocarbon stream in an olefin enrichment zone under olefin enrichment conditions to provide an olefin enriched hydrocarbon stream, contacting the olefin enriched hydrocarbon stream with an ionic liquid catalyst in a hydrocarbon conversion zone under hydrocarbon conversion conditions to provide a converted hydrocarbon stream comprising one or more halogenated components, and removing the one or more halogenated components from the converted hydrocarbon stream to provide a dechlorinated hydrocarbon product.

In an embodiment, the present invention also provides an ionic liquid catalyzed hydrocarbon conversion process comprising contacting an oxygenate containing hydrocarbon stream with a dehydration catalyst in a dehydration zone under dehydration conditions to provide an olefin enriched hydrocarbon stream, contacting the olefin enriched hydrocarbon stream with an ionic liquid catalyst in an alkylation zone under alkylation conditions to provide an alkylate product comprising one or more halogenated components, and contacting the alkylate product with a hydrodechlorination catalyst in the presence of hydrogen in a hydrodechlorination zone under hydrodechlorination conditions to provide a dechlorinated alkylate product.

In another embodiment, the present invention further provides an ionic liquid catalyzed hydrocarbon conversion process comprising contacting an oxygenate containing hydrocarbon stream with a dehydration catalyst in a dehydration zone under dehydration conditions to provide an olefin enriched hydrocarbon stream, contacting the olefin enriched hydrocarbon stream with an ionic liquid catalyst in an oligomerization zone under oligomerization conditions to provide an oligomeric product comprising one or more halogenated components, and contacting the oligomeric product with a hydrodechlorination catalyst in the presence of hydrogen in a hydrodechlorination zone under hydrodechlorination conditions to provide a dechlorinated oligomeric product.

As used herein, the terms “comprising” and “comprises” mean the inclusion of named elements or steps that are identified following those terms, but not necessarily excluding other unnamed elements or steps.

The term “Periodic Table” as referred to herein is the IUPAC version of the Periodic Table of the Elements dated Jun. 22, 2007, and the numbering scheme for the Periodic Table Groups is as described in Chemical and Engineering News, 63(5), 27 (1985).

DETAILED DESCRIPTION

According to one aspect of the present invention, oxygenate containing hydrocarbon streams may be upgraded to high value products using ionic liquid catalyzed processes. In an embodiment, a hydrocarbon stream containing substantial quantities of both olefins and oxygenates may be pre-treated in an olefin enrichment zone under olefin enrichment conditions to provide an oxygenate depleted, olefin enriched hydrocarbon stream. In a sub-embodiment, alcohols in an oxygenate containing hydrocarbon stream may be converted, via dehydration, to olefins. The depletion of oxygenates in the oxygenate containing hydrocarbon stream may prevent oxygenate-mediated deactivation of the ionic liquid catalyst. Furthermore, olefin enrichment of the hydrocarbon stream increases the olefin content of the feed, thereby increasing the product yield obtained from the ionic liquid catalyzed hydrocarbon conversion process.

In an embodiment, the olefins in the olefin enriched hydrocarbon stream may be oligomerized by contacting the olefin enriched hydrocarbon stream with an ionic liquid catalyst under oligomerization conditions. In another embodiment, the olefin enriched hydrocarbon stream may comprise isoparaffins as well as olefins, and the olefins may be alkylated with the isoparaffins by contacting the olefin enriched hydrocarbon stream with an ionic liquid catalyst under alkylation conditions.

In a sub-embodiment, an ancillary hydrocarbon stream, e.g., comprising isoparaffins, may be contacted with the olefin enriched hydrocarbon stream in the presence of an ionic liquid catalyst in the hydrocarbon conversion zone. Examples of isoparaffin containing streams include, but are not limited to, FCC naphtha, hydrocracker naphtha, coker naphtha, Fischer-Tropsch condensate, and cracked naphtha. In yet another embodiment, the hydrocarbon conversion conditions in the hydrocarbon conversion zone may be suitable for both alkylation and oligomerization, such that both alkylation and oligomerization may take place concurrently in a single hydrocarbon conversion zone.

Ionic liquid catalyzed processes of the present invention may be performed in the presence of a co-catalyst or promoter to provide enhanced or improved catalytic activity. A co-catalyst according to the present invention may comprise, for example, anhydrous HCl or organic chloride (see, e.g., U.S. Pat. Nos. 7,495,144 to Elomari, and 7,531,707 to Harris et al., the disclosures of which are incorporated by reference herein in their entirety). When organic chloride is used as the co-catalyst with the ionic liquid, HCl may be formed in situ in the reactor during the hydrocarbon conversion process.

Products and/or by-products from ionic liquid catalyzed hydrocarbon conversion processes may typically include one or more halogenated components, as disclosed in commonly assigned co-pending patent application Serial No. 12/847,313 entitled Hydrodechlorination of ionic liquid-derived hydrocarbon products, filed on Jul. 30, 2010, the disclosure of which is incorporated by reference herein in its entirety.

Products of ionic liquid catalyzed hydrocarbon conversion processes of the instant invention may be dechlorinated in a dechlorination zone, for example, by hot caustic treatment, adsorption of organochlorine species using a suitable adsorbent, or catalytic hydrodechlorination, to provide one or more dechlorinated product(s). In an embodiment, catalytic hydrodechlorination may involve contacting the hydrocarbon conversion stream from an ionic liquid catalyzed reaction with a hydrodechlorination catalyst in a hydrodechlorination zone in the presence of hydrogen at relatively low pressure. According to one aspect of the present invention, the chloride content of the dechlorinated products will be sufficiently low to allow the blending of such materials into refinery product streams.

Ionic Liquid Catalysts

In an embodiment, processes according to the present invention may use a catalytic composition comprising at least one metal halide and at least one quaternary ammonium halide and/or at least one amine halohydride. The ionic liquid catalyst can be any halogen aluminate ionic liquid catalyst, e.g., comprising an alkyl substituted quaternary amine halide, an alkyl substituted pyridinium halide, or an alkyl substituted imidazolium halide of the general formula N⁺R₄X⁻.

As an example, ionic liquid catalysts useful in practicing the present invention may be represented by the general formulas A and B,

wherein R═H, methyl, ethyl, propyl, butyl, pentyl or hexyl, and X is a halide, and R₁ and R₂═H, methyl, ethyl, propyl, butyl, pentyl or hexyl, wherein R₁ and R₂ may or may not be the same. In an embodiment, X is chloride.

An exemplary metal halide that may be used in accordance with the present invention is aluminum chloride (AlCl₃). Quaternary ammonium halides which can be used in accordance with the present invention include those described in U.S. Pat. No. 5,750,455, the disclosure of which is incorporated by reference herein.

In an embodiment, the ionic liquid catalyst may be a chloroaluminate ionic liquid prepared by mixing AlCl₃ and an alkyl substituted pyridinium halide, an alkyl substituted imidazolium halide, a trialkylammonium hydrohalide, or a tetraalkylammonium halide, as disclosed in commonly assigned U.S. Pat. No. 7,495,144, the disclosure of which is incorporated by reference herein in its entirety.

In a sub-embodiment, the ionic liquid catalyst may comprise N-butylpyridinium heptachlorodialuminate ionic liquid, which may be prepared, for example, by combining AlCl₃ with a salt of the general formula A, supra, wherein R is n-butyl and X is chloride. The present invention is not limited to any particular ionic liquid catalyst composition(s).

Oxygenate Containing Feedstocks for Ionic Liquid Catalyzed Processes

In an embodiment, feeds for the present invention may comprise oxygenate- and olefin containing hydrocarbon streams, such as various streams in a petroleum refinery, a gas-to-liquid conversion plant, or a coal-to-liquid (CTL) conversion plant, including streams from Fischer-Tropsch synthesis units, naphtha crackers, middle distillate crackers or wax crackers, as well as FCC offgas, FCC light naphtha, coker offgas, coker naphtha, and the like. Some such streams may contain significant amounts of isoparaffin(s) in addition to olefin(s) and oxygenates. In a sub-embodiment, the oxygenate containing hydrocarbon stream may comprise a Fischer-Tropsch condensate.

As a non-limiting example, an oxygenate containing hydrocarbon stream useful in practicing the instant invention may typically comprise from about 1 to 70 wt % olefins, and from about 0.1 to 30 wt % oxygenates. The oxygenate components of the oxygenated olefin containing hydrocarbon stream may comprise from about 0.1 to 30 wt % C₂-C₂₀ alkanols, together with C₁-C₂₀ carboxylic acids. Such streams may be fed to an olefin enrichment unit or zone to provide an olefin enriched hydrocarbon stream. The olefin enriched hydrocarbon stream may typically comprise from about 1 to 90 wt % olefins, and typically less than about 0.5 wt % oxygenates. The olefin enriched hydrocarbon stream may be fed to a hydrocarbon conversion unit 110 of the present invention (see, e.g., FIG. 1).

The oxygenate containing hydrocarbon stream may comprise a mixture of hydrocarbons having a range of chain lengths and thus a wide boiling range. In an embodiment, the oxygenate containing hydrocarbon stream may contain two or more olefins selected from ethylene, propylene, butylenes, pentenes, and up to O₃₆ olefins. The oxygenate containing hydrocarbon stream may comprise alpha-olefins and/or internal olefins (i.e., having an internal double bond). The olefins may be either straight chain, or branched, or a mixture of the two. In an embodiment of the present invention, the oxygenate containing hydrocarbon stream may comprise a mixture of mostly linear olefins from C₂ to about C₃₆. In another embodiment, the olefins in the oxygenate containing hydrocarbon stream may comprise at least about 10% of alpha-olefin species. In a sub-embodiment, the olefins in the oxygenate containing hydrocarbon stream may comprise predominantly alpha-olefins.

In an embodiment, olefins in the olefin enriched hydrocarbon stream may undergo oligomerization when contacted with an ionic liquid catalyst in hydrocarbon conversion unit 110 (see, e.g., FIG. 1). Ionic liquid catalyzed olefin oligomerization may take place under the same or similar conditions as ionic liquid catalyzed olefin-isoparaffin alkylation. As a result, in an embodiment of the present invention, both olefin oligomerization and olefin/isoparaffin alkylation may take place in a single hydrocarbon conversion zone.

Ionic Liquid Catalyzed Hydrocarbon Conversion Systems and Processes

With reference to FIG. 1, a hydrocarbon conversion system 10 for processing an oxygenate containing hydrocarbon feed using an ionic liquid catalyst, according to an embodiment of the present invention, may include an olefin enrichment unit 100, a hydrocarbon conversion unit 110, and a dechlorination unit 120.

During an ionic liquid catalyzed hydrocarbon conversion process of the instant invention, an oxygenate containing hydrocarbon stream may be treated in olefin enrichment unit 100 under olefin enrichment conditions to provide an olefin enriched hydrocarbon stream. Olefin enrichment unit 100 may also be referred to herein as an olefin enrichment zone. In an embodiment, the oxygenate containing hydrocarbon stream may typically comprise from about 0.1 to 30 wt % oxygenates, and often from about 0.1 to 20 wt % oxygenates.

In an embodiment, the oxygenate containing hydrocarbon stream may be enriched in olefins by converting the oxygenates in the stream to olefins. In an embodiment, oxygenates in the oxygenate containing hydrocarbon stream may comprise alcohols, and the alcohols may be converted to olefins by dehydration of the alcohol by treatment with a dehydrating catalyst. In a sub-embodiment, the oxygenates in the oxygenate containing hydrocarbon stream may be comprised predominantly of primary alcohols.

In an embodiment, treating the oxygenate containing hydrocarbon stream in olefin enrichment unit 100 may further include the removal of oxygenates and/or water from the oxygenate containing hydrocarbon stream (see, for example, FIG. 2). Various methods and techniques for removing oxygenates from hydrocarbon streams are disclosed in U.S. Pat. No. 6,743,962 to O'Rear et al., the disclosure of which is incorporated by reference herein in its entirety.

During an ionic liquid catalyzed hydrocarbon conversion process of the instant invention, the olefin enriched hydrocarbon stream from unit 100 may be introduced into hydrocarbon conversion unit 110. Hydrocarbon conversion unit 110 may also be referred to herein as a hydrocarbon conversion zone. In an embodiment, the olefin enriched hydrocarbon stream may typically comprise from about 1 to 70 wt % olefins, and often from about 10 to 60 wt % olefins. In an embodiment, the olefin enriched hydrocarbon stream may typically comprise less than about 0.5 wt % oxygenates, and often less than about 0.3 wt % oxygenates.

In an embodiment, the olefin enriched hydrocarbon stream and the ionic liquid catalyst may be introduced into hydrocarbon conversion unit 110 via separate inlet ports (not shown). The olefin enriched hydrocarbon stream may be contacted with the ionic liquid catalyst in hydrocarbon conversion unit 110 under hydrocarbon conversion conditions to provide a converted hydrocarbon stream. In an embodiment, the ionic liquid catalyst may comprise a chloroaluminate ionic liquid. The feeds to hydrocarbon conversion unit 110 may further include a catalyst promoter, such as anhydrous HCl or an alkyl halide. In an embodiment, the catalyst promoter may comprise a C₂-C₆ alkyl chloride, such as n-butyl chloride or t-butyl chloride. Hydrocarbon conversion unit 110 may be vigorously mixed to promote contact between reactant(s) and ionic liquid catalyst.

Hydrocarbon conversion conditions within hydrocarbon conversion unit 110 may be adjusted to optimize process performance for a particular hydrocarbon conversion process of the present invention. In an embodiment, the hydrocarbon conversion conditions may comprise oligomerization conditions, such that olefins in the olefin enriched stream may be oligomerized to provide one or more oligomeric products. In another embodiment, the hydrocarbon conversion conditions may comprise alkylation conditions, such that olefins in the olefin enriched stream may be alkylated with isoparaffins to provide an alkylate product. In yet another embodiment, the hydrocarbon conversion conditions may comprise both oligomerization conditions and alkylation conditions, such that oligomerization and alkylation reactions may occur concurrently within hydrocarbon conversion unit 110.

In an embodiment, an ancillary hydrocarbon stream, e.g., comprising isoparaffins, may optionally be fed to hydrocarbon conversion unit 110, and the ancillary hydrocarbon stream may be contacted with the olefin enriched hydrocarbon stream in the presence of ionic liquid catalyst in the hydrocarbon conversion zone.

During hydrocarbon conversion processes of the invention, hydrocarbon conversion unit 110 may contain a mixture comprising ionic liquid catalyst and a hydrocarbon phase. The hydrocarbon phase may comprise at least one hydrocarbon conversion product of the ionic liquid catalyzed reaction. In an embodiment, the ionic liquid catalyst may be separated from the hydrocarbon phase via a catalyst/hydrocarbon separator (not shown), wherein the hydrocarbon and ionic liquid catalyst phases may be allowed to settle under gravity, by using a coalescer, or by a combination thereof. The use of coalescers for liquid-liquid separations is described in commonly assigned US Pub. No. 20100130800A1, the disclosure of which is incorporated by reference herein in its entirety.

The hydrocarbon phase may be fed to dechlorination unit 120, while at least a portion of the ionic liquid phase may be recycled to hydrocarbon conversion unit 110. The hydrocarbon phase fed to dechlorination unit 120 may be referred to herein as a converted hydrocarbon stream. According to one aspect of the present invention, the converted hydrocarbon stream provided by hydroconversion unit 110 may comprise a distillate enriched stream. According to another aspect of the present invention, the converted hydrocarbon stream provided by hydroconversion unit 110 may comprise a base oil (700° F.+) enriched stream.

Reaction Conditions for Ionic Liquid Catalyzed Hydrocarbon Conversions

Due to the low solubility of hydrocarbons in ionic liquids, hydrocarbon conversion reactions in ionic liquids (including olefin oligomerization and isoparaffin-olefin alkylation reactions) are generally biphasic and occur at the interface in the liquid state. The volume of ionic liquid catalyst in the reactor may be generally in the range from about 1 to 70 vol %, and usually from about 4 to 50 vol %. Generally, vigorous mixing (e.g., stirring or Venturi nozzle dispensing) is used to ensure good contact between the reactants and the ionic liquid catalyst. The reaction temperature may be generally in the range from about −40° F. to +480° F., typically from about −4° F. to +210° F., and often from about +40° F. to +140° F. The reactor pressure may be in the range from atmospheric pressure to about 8000 kPa. Typically, the reactor pressure will be sufficient to keep the reactants in the liquid phase.

Residence time of reactants in the reactor may generally be in the range from a few seconds to hours, and usually from about 0.5 min to 60 min. In the case of ionic liquid catalyzed isoparaffin-olefin alkylation, the reactants may be introduced in an isoparaffin:olefin molar ratio generally in the range from about 1 to 100, more typically from about 2 to 50, and often from about 2 to 20. Heat generated by the reaction may be dissipated using various means well known to the skilled artisan.

With continued operation of hydrocarbon conversion unit 110, the ionic liquid catalyst may become partially deactivated or spent. In order to maintain the catalytic activity, at least a portion of the ionic liquid phase may be fed to a catalyst regeneration unit (not shown) for regeneration of the ionic liquid catalyst. Processes for the regeneration of ionic liquid catalyst to provide steady state catalytic activity are disclosed in the patent literature (see, for example, U.S. Pat. Nos. 7,732,364 and 7,674,739, the disclosures of which are incorporated by reference herein in their entirety).

Dechlorination of Ionic Liquid Catalyzed Hydrocarbon Conversion Products

In an embodiment of the present invention, the converted hydrocarbon stream obtained from hydrocarbon conversion unit 110 may typically comprise one or more halogenated components. As an example only, the converted hydrocarbon stream may have an organic chloride content generally greater than about 50 ppm, typically greater than about 200 ppm, and often greater than about 1000 ppm. In an embodiment, the converted hydrocarbon stream from hydrocarbon conversion unit 110 may have an organic chloride content generally in the range from about 50 ppm to 5000 ppm, typically from about 100 ppm to 4000 ppm, and often from about 200 ppm to 3000 ppm.

According to an aspect of the instant invention, the converted hydrocarbon stream may be fed to dechlorination unit 120 for dechlorinating the hydrocarbon product(s) to provide one or more dechlorinated hydrocarbon products. Dechlorination unit 120 may also be referred to herein as a dechlorination zone. In an embodiment, the converted hydrocarbon stream may be dechlorinated by treatment with hot caustic. In another embodiment, the converted hydrocarbon stream may be dechlorinated by adsorption of organochlorine species using an adsorbent such as zeolites, clay, alumina, silica-alumina, and the like.

According to another embodiment of the instant invention, dechlorination unit 120 may comprises a hydrodechlorination unit or zone, and the converted hydrocarbon stream may be fed to dechlorination unit 120 for hydrodechlorinating the hydrocarbon product(s) by contacting the converted hydrocarbon stream with a hydrodechlorination catalyst in the presence of hydrogen under hydrodechlorination conditions to provide one or more dechlorinated hydrocarbon products. The hydrodechlorination catalyst may comprise an element selected from the group consisting of elements of Groups 6, 8, 9, 10, and 11 of the Periodic Table, and combinations thereof, present as metals, oxides, or sulfides. In a sub-embodiment, the hydrodechlorination catalyst may comprise an element selected from Pd, Pt, Au, Ni, Co, Mo, and W, and their mixtures, present as metals, oxides, or sulfides.

The hydrodechlorination catalyst may further comprise a support. The support may comprise an inorganic porous material, such as a refractory oxide, or activated carbon. Examples of refractory oxide support materials include alumina, silica, titania, alumina-silica, and zirconia, or the like, and combinations thereof. In an embodiment, the hydrodechlorination catalyst may comprise a noble metal on a refractory oxide support. In a sub-embodiment, the hydrodechlorination catalyst may comprise Pd or Pt or a mixture of Pd and Pt, e.g., in the range from about 0.05 to 3.0 wt % of Pd or Pt or a mixture thereof.

The hydrodechlorination conditions within the hydrodechlorination zone may include a reaction temperature generally in the range from about 300° F. to 750° F., and typically from about 400° F. to 650° F. The hydrodechlorination conditions may further include a reaction pressure generally in the range from about 100 to 5000 psig, and typically from about 200 to 2000 psig. A liquid hourly space velocity (LHSV) feed rate to the hydrodechlorination zone may be generally in the range from about 0.1 to 50 hr⁻¹, and typically from about 0.2 to 10 hr⁻¹. A hydrogen supply to the hydrodechlorination zone may be generally in the range from about 50 to 8000 standard cubic feet per barrel (SCFB) of the hydrocarbon stream, and typically from about 100 to 5000 SCFB.

The dechlorinated hydrocarbon product obtained from dechlorination unit 120 may typically have a much lower chloride content as compared with that of the converted hydrocarbon stream fed to dechlorination unit 120. In an embodiment, a first chloride content of the hydrocarbon stream fed to dechlorination unit 120 may be greater than about 50 ppm. In an embodiment, the hydrocarbon stream fed to dechlorination unit 120 may have an organic chloride content generally in the range from about 50 ppm to 5000 ppm, typically from about 100 ppm to 4000 ppm, and often from about 200 ppm to 3000 ppm.

In contrast, the organic chloride content of the dechlorinated hydrocarbon product(s) obtained from hydrocarbon conversion system 10 may be greatly decreased as compared with that of the converted hydrocarbon stream. Typically, a second chloride content of dechlorinated hydrocarbon product(s) provided by processes of the present invention may be less than 50 ppm, typically less than about 10 ppm, and often equal to or less than about 5 ppm. Analogous results will be obtained when the present invention is practiced using ionic liquid catalyst systems based on halides other than chlorides. In an embodiment, the dechlorinated hydrocarbon product(s) may comprise a dechlorinated distillate fuel, such as dechlorinated jet fuel, or dechlorinated diesel fuel, and the like.

Olefin Enrichment of Oxygenate Containing Hydrocarbon Streams

FIG. 2 represents a scheme for an olefin enrichment process using an oxygenate containing hydrocarbon feed, according to an aspect of the process of FIG. 1. The oxygenate containing hydrocarbon stream may be, for example, any of various hydrocarbon streams, which contain significant or substantial amounts of oxygenates, in a petroleum refinery, a gas-to-liquid conversion plant, or a coal-to-liquid conversion plant, and the like. In an embodiment, an oxygenate containing hydrocarbon stream of the present invention may comprise Fischer-Tropsch condensate.

With further reference to FIG. 2, olefin enrichment unit 100 for treating an oxygenate containing hydrocarbon stream may include an oxygenate dehydration unit 102. Oxygenate dehydration unit 102 may include a dehydration catalyst. Oxygenate dehydration unit 102 may also be referred to herein as a dehydration zone. In an embodiment, a process for treating an oxygenate containing hydrocarbon stream may comprise dehydrating oxygenates in the oxygenate containing hydrocarbon stream by contacting the oxygenate containing hydrocarbon stream with the dehydration catalyst in the dehydration zone under dehydration conditions.

In an embodiment, oxygenates present in the oxygenate containing hydrocarbon stream may comprise predominantly alcohols. The alcohols may be converted to olefins by contacting the oxygenate containing hydrocarbon stream with the dehydration catalyst to provide an olefin enriched hydrocarbon stream.

Carboxylic acids in the hydrocarbon stream may be decarboxylated by contacting the hydrocarbon stream with the dehydration catalyst. In an embodiment, the olefin enriched hydrocarbon stream may comprise less than about 0.5 wt % oxygen. In a sub-embodiment, the olefin enriched hydrocarbon stream may comprise less than about 0.3 wt % oxygen.

In an embodiment, the dehydration catalyst may be selected from the group consisting of alumina and amorphous silica-alumina. In a sub-embodiment, the dehydration catalyst may comprise alumina doped with an element selected from the group consisting of phosphorus, boron, fluorine, zirconium, titanium, gallium, magnesium, and combinations thereof. In another sub-embodiment, the dehydration catalyst may comprise amorphous silica-alumina doped with an element selected from the group consisting of phosphorus, boron, fluorine, zirconium, titanium, gallium, magnesium and combinations thereof.

According to one aspect of the present invention, the degree of acidity of the dehydration catalyst may be selected, e.g., by the judicious doping of alumina or amorphous silica-alumina, to determine not only the degree of olefin isomerization, but also the proportion of alpha-olefins to total olefins in the olefin enriched hydrocarbon stream. The olefin composition of the olefin enriched hydrocarbon stream may in turn determine the composition of product(s) obtained from hydrocarbon conversion system 10.

The dehydration conditions for dehydrating oxygenates in the oxygenate containing hydrocarbon stream may include a temperature in the range from about 400° F. to 800° F., a pressure in the range from about 10 to 5000 psig, and a liquid hourly space velocity (LHSV) feed rate in the range from about 0.1 to 50 hr⁻¹.

With still further reference to FIG. 2, olefin enrichment unit 100 may optionally still further include one or more of an oxygenate extraction unit 104, an oxygenate adsorption unit 106, and a second distillation unit 108. In an embodiment, the treatment of an oxygenate containing hydrocarbon stream according to the present invention may optionally include the use of oxygenate extraction unit 104 for extracting or washing the hydrocarbon stream with an aqueous medium, whereby residual oxygenates may be removed from the hydrocarbon stream exiting dehydration unit 102. In a sub-embodiment, the aqueous medium may comprise liquid water. In a further sub-embodiment, the aqueous medium may comprise water at a pH>7.0.

In an embodiment, an olefin enrichment process of the present invention may optionally further include contacting the hydrocarbon stream with an adsorbent in oxygenate adsorption unit 106, whereby residual oxygenates and/or water may be removed from the hydrocarbon stream. In a sub-embodiment, the adsorbent may comprise a molecular sieve, such as zeolite 13X. Zeolites and molecular sieves are well known in the art (see, for example, Zeolites in Industrial Separation and Catalysis, By Santi Kulprathipanja, Pub. Wiley-VCH, 2010). In an embodiment, the hydrocarbon stream may be fed to adsorption unit 106 from oxygenate extraction unit 104. Alternatively, oxygenate extraction unit 104 may be omitted or bypassed, and the hydrocarbon stream may be fed to adsorption unit 106 directly from dehydration unit 102.

In yet another embodiment of the present invention, olefin enrichment unit 100 may optionally further include a second distillation unit 108. As a non-limiting example, second distillation unit 108 may be used to remove a heavy fraction from the hydrocarbon stream prior to ionic liquid catalyzed hydrocarbon conversion of the olefin enriched hydrocarbon stream. The nature of the heavy fraction, if any, to be separated from the olefin enriched hydrocarbon stream may vary, for example, according to the feedstocks used and the product(s) targeted from the ionic liquid catalyzed hydrocarbon conversion processes of various embodiments of the present invention.

Certain features of the various embodiments may be combined with features of other embodiments to provide further embodiments of the present invention in addition to those embodiments specifically described or shown as such.

There are numerous variations on the present invention which are possible in light of the teachings herein. It is therefore understood that within the scope of the following claims, the invention may be practiced otherwise than as specifically described or exemplified herein.

Claims

1. An ionic liquid catalyzed hydrocarbon conversion process, comprising:

a) treating an oxygenate containing hydrocarbon stream in an olefin enrichment zone under olefin enrichment conditions to provide an olefin enriched hydrocarbon stream comprising olefins;

b) contacting the olefin enriched hydrocarbon stream with an ionic liquid catalyst in a hydrocarbon conversion zone under hydrocarbon conversion conditions to provide a converted hydrocarbon stream comprising one or more halogenated components; and

c) removing the halogenated components from the converted hydrocarbon stream to provide a dechlorinated hydrocarbon product.

2. The process according to claim 1, wherein step c) comprises contacting the converted hydrocarbon stream with a hydrodechlorination catalyst in the presence of hydrogen in a hydrodechlorination zone under hydrodechlorination conditions.

3. The process according to claim 1, wherein step a) comprises contacting the oxygenate containing hydrocarbon stream with a dehydration catalyst in a dehydration zone under dehydration conditions.

4. The process according to claim 1, further comprising:

d) prior to step b), washing the olefin enriched hydrocarbon stream with an aqueous medium, whereby residual oxygenates are removed from the olefin enriched hydrocarbon stream.

5. The process according to claim 1, further comprising:

e) prior to step b), contacting the olefin enriched hydrocarbon stream with an adsorbent, whereby residual oxygenates and water are removed from the olefin enriched hydrocarbon stream.

6. The process according to claim 5, wherein the adsorbent comprises a molecular sieve.

7. The process according to claim 3, wherein the dehydration catalyst is selected from the group consisting of alumina and amorphous silica-alumina.

8. The process according to claim 3, wherein the dehydration catalyst comprises alumina doped with an element selected from the group consisting of phosphorus, boron, fluorine, zirconium, titanium, gallium, magnesium, and combinations thereof.

9. The process according to claim 3, wherein the dehydration catalyst comprises amorphous silica-alumina doped with an element selected from the group consisting of phosphorus, boron, fluorine, zirconium, titanium, gallium, magnesium, and combinations thereof.

10. The process according to claim 1, wherein the hydrocarbon conversion conditions comprise oligomerization conditions, and wherein olefins in the olefin enriched hydrocarbon stream are oligomerized.

11. The process according to claim 1, wherein the olefin enriched hydrocarbon stream further comprises isoparaffins, and the hydrocarbon conversion conditions comprise alkylation conditions, wherein olefins in the olefin enriched hydrocarbon stream are alkylated with the isoparaffins.

12. The process according to claim 1, wherein the hydrocarbon conversion conditions comprise oligomerization conditions and alkylation conditions.

13. The process according to claim 1, wherein the oxygenate containing hydrocarbon stream comprises a Fischer-Tropsch condensate.

14. The process according to claim 2, wherein a first chloride content of the converted hydrocarbon stream is greater than 50 ppm, and a second chloride content of the dechlorinated hydrocarbon product is less than 50 ppm.

15. The process according to claim 1, wherein the converted hydrocarbon stream comprises a distillate enriched stream.

16. The process according to claim 1, wherein the converted hydrocarbon stream comprises a base oil (700° F.+) enriched stream.

17. The process according to claim 1, wherein the ionic liquid catalyst comprises a chloroaluminate ionic liquid.

18. An ionic liquid catalyzed hydrocarbon conversion process, comprising:

a) contacting an oxygenate containing hydrocarbon stream with a dehydration catalyst in a dehydration zone under dehydration conditions to provide an olefin enriched hydrocarbon stream;

b) contacting the olefin enriched hydrocarbon stream with an ionic liquid catalyst in an alkylation zone under alkylation conditions to provide an alkylate product comprising one or more halogenated components; and

c) contacting the alkylate product with a hydrodechlorination catalyst in the presence of hydrogen in a hydrodechlorination zone under hydrodechlorination conditions to provide a dechlorinated alkylate product.

19. The process according to claim 18, wherein:

the hydrodechlorination catalyst comprises an element selected from the group consisting of elements of Groups 6, 8, 9, 10, and 11 of the Periodic Table, and combinations thereof, present as metals, oxides, or sulfides; and

step c) comprises contacting the alkylate product with the hydrodechlorination catalyst at a temperature in the range from about 300° F. to 750° F., a pressure in the range from about 100 to 5000 psig, a liquid hourly space velocity (LHSV) feed rate in the range from about 0.1 to 50, and a hydrogen supply in the range from about 200 to 8000 standard cubic feet per barrel (SCFB) of the alkylate product.

20. An ionic liquid catalyzed hydrocarbon conversion process, comprising:

a) contacting an oxygenate containing hydrocarbon stream with a dehydration catalyst in a dehydration zone under dehydration conditions to provide an olefin enriched hydrocarbon stream;

b) contacting the olefin enriched hydrocarbon stream with an ionic liquid catalyst in an oligomerization zone under oligomerization conditions to provide an oligomeric product comprising one or more halogenated components; and

c) contacting the oligomeric product with a hydrodechlorination catalyst in the presence of hydrogen in a hydrodechlorination zone under hydrodechlorination conditions to provide a dechlorinated oligomeric product.

21. The process according to claim 20, wherein:

the hydrodechlorination catalyst comprises an element selected from the group consisting of elements of Groups 6, 8, 9, 10, and 11 of the Periodic Table, and combinations thereof, present as metals, oxides, or sulfides; and

step c) comprises contacting the oligomeric product with the hydrodechlorination catalyst at a temperature in the range from about 300° F. to 750° F., a pressure in the range from about 100 to 5000 psig, a liquid hourly space velocity (LHSV) feed rate in the range from about 0.1 to 50, and a hydrogen supply in the range from about 200 to 8000 standard cubic feet per barrel (SCFB) of the oligomeric product.