Patent Application
20150025285
The present invention relates to processes for regenerating olefin treating adsorbents for the removal of oxygenate contaminants.
Various refinery and petrochemical processes involve reacting light olefins, to produce transportation fuels, plastics, and other commercial products, using catalyst systems that can be poisoned by contaminants in the olefin feed. Such contaminants may include water as well as various oxygenates, e.g., alcohols, ketones, carboxylic acids, and ethers.
Adsorbent materials for removing the water and oxygenates from the olefin feed become spent after use for a limited time period and must be regenerated for re-use to avoid excessive consumption and cost of the adsorbents. Spent adsorbent can be regenerated by desorbing the water and oxygenates into a stream of hot hydrocarbon vapor, e.g., isobutane. Such hydrocarbons may be valuable as feeds to various refinery processes. For example, isobutane is a valuable feed to ionic liquid alkylation. However, isobutane regenerant becomes contaminated with oxygenates and water during adsorbent regeneration. It is advantageous to remove the contaminants from the isobutane to prevent the accumulation of water and oxygenates, which could otherwise eventually break through the adsorbent beds and cause catalyst deactivation.
There is a need for processes for the elimination of oxygenate contaminants from light hydrocarbon processing systems in order to prevent contaminant accumulation in such systems, thereby protecting catalysts from deactivation by the contaminants.
In one embodiment there is provided a process for eliminating oxygenates from a light hydrocarbon processing system, the process comprising feeding an olefin stream to an oxygenate adsorption unit to provide a deoxygenated olefin stream; after the feeding step, desorbing oxygenates from the oxygenate adsorption unit via a regenerant stream to provide an oxygenated regenerant stream comprising the oxygenates; and converting the oxygenates of the oxygenated regenerant stream to paraffins and water.
In another embodiment there is provided a process for eliminating oxygenates from a light hydrocarbon processing system, the process comprising removing oxygenates from an olefin stream via an oxygenate adsorption unit to provide a deoxygenated olefin stream, wherein the oxygenate adsorption unit becomes spent; regenerating the spent oxygenate adsorption unit via a regenerant stream to provide an oxygenated regenerant stream comprising the oxygenates; and contacting the oxygenated regenerant stream with a hydro-deoxygenation catalyst in the presence of hydrogen gas in a hydro-deoxygenation zone under hydro-deoxygenation conditions, wherein the oxygenates of the oxygenated regenerant stream are converted to paraffins and water.
In a further embodiment there is provided a process for eliminating oxygenates from a light hydrocarbon processing system, the process comprising feeding an olefin stream to an oxygenate adsorption unit to provide a deoxygenated olefin stream; contacting the deoxygenated olefin stream and an isoparaffin stream with an ionic liquid catalyst in an ionic liquid alkylation zone under ionic liquid alkylation conditions; separating an alkylation hydrocarbon phase from an effluent of the ionic liquid alkylation zone; fractionating the alkylation hydrocarbon phase to provide an alkylate product; when the oxygenate adsorption unit becomes spent, regenerating the spent oxygenate adsorption unit via a regenerant stream to provide an oxygenated regenerant stream comprising oxygenates; and converting the oxygenates of the oxygenated regenerant stream to paraffins and water.
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.
Various refinery and petrochemical processes use light olefins, such as propene and butenes, as feeds to produce commercial products. An exemplary process is the alkylation of olefins with isobutane to produce high octane motor gasoline using ionic liquid catalysts. Refinery olefin streams, e.g., from a fluid catalytic cracking (FCC) unit, are typically contaminated with both water and oxygenates. It may be desirable or necessary to decrease the amount of water and/or oxygenates in olefin feeds for ionic liquid alkylation to very low levels before the olefin feed contacts the ionic liquid catalyst.
Adsorbent materials used for removing water and oxygenates from an olefin feed become spent after use for a limited time period. Spent adsorbent can be regenerated by desorbing the water and oxygenates into a regenerant stream, e.g., comprising hot hydrocarbon vapor. Oxygenates, such as alcohols and ketones, are typically more difficult to remove than water due to their much higher solubility in hydrocarbon liquids.
As disclosed herein, oxygenates as well as water can be permanently removed or eliminated from a light hydrocarbon processing system to prevent contaminant induced catalyst deactivation. For example, applicants have found that oxygenates can be removed from an oxygenated regenerant stream from an oxygenate adsorption unit by converting the oxygenates in the oxygenated regenerant stream to paraffins and water.
The term “deoxygenated” may be used herein to refer to a hydrocarbon stream from which one or more oxygenates may have been adsorbed or otherwise removed, such that the hydrocarbon feed stream or regenerant stream may be depleted in the one or more oxygenates; a deoxygenated stream may similarly be depleted in water.
The term “oxygenated” may be used herein to refer to a regenerant stream into which one or more oxygenates may have been desorbed, such that the regenerant stream may be enriched in the one or more oxygenates; an oxygenated stream may similarly be enriched in water.
Applicants have found that oxygenate and water may be effectively eliminated from olefin streams to provide deoxygenated olefin streams. Such olefin streams may be suitable for light hydrocarbon processing, including ionic liquid catalyzed alkylation.
Oxygenate Removal for Light Hydrocarbon Processing
Oxygenate adsorption unit 20 may comprise an adsorbent for selectively adsorbing water and oxygenates from olefin stream 15. As a non-limiting example, an adsorbent of oxygenate adsorption unit 20 may comprise at least one of a molecular sieve and a metal oxide. Non-limiting examples of adsorbents for use in oxygenate adsorption unit 20 include a molecular sieve selected from the group consisting of silicates, aluminosilicates, aluminophosphates, silicoaluminophosphates, and combinations thereof. In a sub-embodiment, an adsorbent for use in oxygenate adsorption unit 20 may comprise a zeolite, such as zeolite 13×. The adsorbent of oxygenate adsorption unit 20 may be disposed in at least one adsorbent bed (not shown).
Oxygenate adsorption unit 20/20′ may be operated in the adsorption mode or the regeneration mode. The regeneration mode may also be referred to herein as a desorption mode.
During the adsorption mode of oxygenate adsorption unit 20, water and oxygenate contaminants may be adsorbed from olefin stream 15. In an embodiment, during the adsorption mode, more than one oxygenate adsorption unit may be arranged in series for the adsorption of water and oxygenates from olefin stream 15. During the adsorption mode, oxygenate adsorption unit 20 may be maintained at a temperature typically in the range from 50 to 150° F. (10 to 65.56 degree Celsius), or from 70 to 130° F. (21.11 to 54.44 degree Celsius). The feed of olefin stream 15 to oxygenate adsorption unit 20 may be either upflow or downflow.
During the adsorption mode, a deoxygenated olefin stream 25 may be obtained from oxygenate adsorption unit 20. The expression “deoxygenated olefin stream” may be used herein to refer to an olefin stream that is depleted in oxygenates as compared with an untreated olefin stream. A deoxygenated olefin stream 25 (e.g.,
In an embodiment, deoxygenated olefin stream 25 may have an oxygenate content of not more than 5 ppmw, or not more than 2 ppmw, or not more than 1 ppmw. In an embodiment, deoxygenated olefin stream 25 may have a water content of not more than 5 ppmw, or not more than 2 ppmw, or not more than 1 ppmw. Deoxygenated olefin stream 25 may be fed via line 22 to one or more downstream unit operations. In an embodiment, deoxygenated olefin stream 25 may be fed to an ionic liquid alkylation zone 120 (see, for example,
Although only one oxygenate adsorption unit 20/20′ is shown in
With further reference to
With further reference to
A regenerant stream 35 that is heated may be fed via line 32 to spent oxygenate adsorption unit 20′. In an embodiment, the feed of the regenerant stream 35 that is heated to the spent oxygenate adsorption unit 20′ (regeneration mode) may be in a direction opposite to that of olefin stream 15 to oxygenate adsorption unit 20 (adsorption mode). In an embodiment, regenerant stream 35 may comprise hydrocarbon vapor, e.g., comprising isobutane.
Water and oxygenates may be desorbed from the spent oxygenate adsorption unit 20′ by regenerant stream 35 to provide an oxygenated regenerant stream 45 comprising the water and oxygenates. Oxygenated regenerant stream 45 may be subjected to hydro-deoxygenation in hydro-deoxygenation zone 50 for the conversion of the oxygenates into paraffins and water. In an embodiment, regenerant stream 35 may be at a temperature below that suitable for the hydro-deoxygenation reaction. For example, as regeneration commences the spent oxygenate adsorption unit 20′ may initially serve to cool the regenerant stream 35.
Accordingly, oxygenated regenerant stream 45 may be fed via line 34 to a second heating unit 40 for heating the oxygenated regenerant stream 45. In an embodiment, second heating unit 40 may be used for heating the oxygenated regenerant stream 45 to a temperature in the range from 350 to 650° F. (176.7 to 343.3 degree Celsius), or from 400 to 500° F. (204.4 to 260 degree Celsius). As the system heats up, the duty of second heating unit 40 may be reduced to maintain the temperature of the inlet to hydro-deoxygenation zone 50. In an embodiment, second heating unit 40 may comprise a heat exchanger.
The oxygenated regenerant stream 45 that is heated may be sent via line 36 towards hydro-deoxygenation zone 50. Hydrogen gas may be injected via line 38 into the oxygenated regenerant stream 45 that is heated. In one embodiment, the injecting of the hydrogen gas into the oxygenated regenerant stream 45 is done at a location upstream from the hydro-deoxygenation zone 50. In an embodiment, the injection of hydrogen gas into the oxygenated regenerant stream 45 that is heated may be performed at a location upstream from hydro-deoxygenation zone 50. In an embodiment, a hydrogen to oxygenated regenerant stream feed ratio may be in the range from 50 to 750 standard cubic feet per barrel (SCF/bbl), or from 50 to 500 SCF/bbl. The oxygenated regenerant stream 45 and hydrogen gas may be contacted with a hydro-deoxygenation catalyst in hydro-deoxygenation zone 50 under hydro-deoxygenation conditions, such that oxygenates in oxygenated regenerant stream 45 may be converted to paraffins and water. The feed of oxygenated regenerant stream 45 to hydro-deoxygenation zone 50 may be upflow or downflow.
The hydro-deoxygenation zone effluent may be fed via line 54 to a cooling unit 60, such that at least a portion of the water of hydro-deoxygenation zone effluent may be separated as condensate. The condensed free water may be permanently removed, e.g., via line 57, to a waste water treatment unit (not shown). The residual effluent may be fed via line 58 to a gravity settler 70 for the separation of residual water, a liquid hydrocarbon phase 64, and hydrogen gas. In an embodiment, gravity settler 70 may comprise a three phase separator and/or a coalescer.
The residual water from gravity settler 70 may be permanently removed from gravity settler 70 via line 62 to the waste water treatment unit. The free water separated from the residual effluent via gravity settler 70 may be referred to herein as “residual water” so as to distinguish it from “condensed water” that was removed from the hydro-deoxygenation effluent by condensation upstream from gravity settler 70, it being understood that at least a portion of the residual water may be subsequently condensed from the residual effluent.
The liquid hydrocarbon phase 64 from gravity settler 70 may comprise oxygenate-derived paraffins as well as hydrocarbon components (e.g., isobutane) from the regenerant stream 35. Liquid hydrocarbon phase 64 may be used for various unit operations. The liquid hydrocarbon phase 64 may comprise a relatively small amount of dissolved water. In an embodiment, liquid hydrocarbon phase 64 may be sent to one or more dryers. In an embodiment, liquid hydrocarbon phase 64 may be combined with olefin stream 15 for drying via oxygenate adsorption unit 20. The hydrogen gas from gravity settler 70 may be sent, for example, to a refinery fuel gas header (not shown) for combustion.
In an embodiment, there is provided herein a process for eliminating oxygenates from a light hydrocarbon processing system. Such process may comprise feeding an olefin stream 15 to an oxygenate adsorption unit 20 to provide a deoxygenated olefin stream 25. In an embodiment, deoxygenated olefin stream 25 provided by oxygenate adsorption unit 20 may have an oxygenate content of not more than 5 ppmw, not more than 2 ppmw, or not more than 1 ppmw. In an embodiment, deoxygenated olefin stream 25 may have a water content of not more than 5 ppmw, not more than 2 ppmw, or not more than 1 ppmw. In an embodiment, the deoxygenated olefin stream 25 and an isoparaffin stream 102 may be contacted with an ionic liquid catalyst 108 in an ionic liquid alkylation zone 120 under ionic liquid alkylation conditions to provide an ionic liquid alkylate (see, for example,
As a result of the feeding step, oxygenates and/or water may be adsorbed from the olefin stream 15 by oxygenate adsorption unit 20, and eventually the oxygenate adsorption unit 20 may become spent. When the oxygenate adsorption unit is spent, the step of feeding the olefin stream 15 thereto may be terminated. Such termination of the feeding step may signal the conclusion of the adsorption mode, and the oxygenate adsorption unit 20/20′ may then transition, or alternate, to the regeneration mode, during which oxygenates may be desorbed from the spent oxygenate adsorption unit 20′. In an embodiment, residual olefins 48 may be recovered from the spent oxygenate adsorption unit 20′ prior to the step of desorbing the oxygenates therefrom.
After the feeding step, and after any recovery of residual olefins 48 from the spent oxygenate adsorption unit 20′, oxygenates may be desorbed from the spent oxygenate adsorption unit 20′ via a regenerant stream 35 to provide an oxygenated regenerant stream 45 comprising the oxygenates. The step of desorbing oxygenates from the spent oxygenate adsorption unit 20′ may comprise heating the regenerant stream 35 to a temperature of at least 250° F. (121.1 degree Celsius), or to a temperature in the range from 350 to 600° F. (176.7 to 315.6 degree Celsius). Thereafter, the regenerant stream 35 that is heated may be passed through the spent oxygenate adsorption unit 20′. For example, in one embodiment, the desorbing of the oxygenates from the oxygenate adsorption unit 20 comprises heating the regenerant stream 35 to a temperature of at least 250° F. (121.1 degree Celsius), and thereafter passing the regenerant stream 35 through the oxygenate adsorption unit 20. In an embodiment, the regenerant stream 35 may comprise a hydrocarbon (e.g., isobutane) vapor.
After the desorbing step, the oxygenates of the oxygenated regenerant stream 45 may be converted to paraffins and water. The step of converting the oxygenates of the oxygenated regenerant stream to paraffins and water may comprise contacting the oxygenated regenerant stream 45 with a hydro-deoxygenation catalyst in the presence of hydrogen gas in a hydro-deoxygenation zone 50 under hydro-deoxygenation conditions. In an embodiment, the hydro-deoxygenation catalyst may comprise a noble metal on a suitable support. In an embodiment, the hydro-deoxygenation catalyst may comprise a noble metal selected from the group consisting of Pt, Pd, and combinations thereof.
Prior to the step of contacting the oxygenated regenerant stream 45 with a hydro-deoxygenation catalyst, the oxygenated regenerant stream may be heated to a suitable hydro-deoxygenation temperature. In an embodiment, the oxygenated regenerant stream 45 may be heated to a temperature in the range from 350 to 650° F. (176.7 to 343.3 degree Celsius), or from 400 to 500° F. (204.4 to 260 degree Celsius).
After the step of heating the oxygenated regenerant stream 45 to a suitable hydro-deoxygenation temperature, hydrogen gas may be injected into the oxygenated regenerant stream. In an embodiment, the hydrogen gas may be injected into the oxygenated regenerant stream 45 at a location upstream from hydro-deoxygenation zone 50.
In an embodiment, the hydro-deoxygenation conditions may comprise a temperature in the range from 350 to 650° F. (176.7 to 343.3 degree Celsius), or from 400 to 500° F. (204.4 to 260 degree Celsius). The hydro-deoxygenation conditions may further comprise a pressure in the range from 100 to 400 psig, or from 100 to 300 psig. The hydro-deoxygenation conditions may still further comprise a liquid hourly space velocity (LHSV) in the range from 2 to 20 hr−1, or from 2 to 10 hr−1.
After the step of contacting the oxygenated regenerant stream 45 with a hydro-deoxygenation catalyst, the hydro-deoxygenation zone effluent may be cooled to condense at least a portion of the water from the hydro-deoxygenation zone effluent to provide condensed water and a residual effluent. The residual effluent may comprise hydrogen gas and residual water, as well as oxygenate-derived paraffins and hydrocarbon components of the regenerant. The hydrogen gas and residual water may be separated from the residual effluent. Both the condensed water and the residual water may be permanently removed from the system.
In another embodiment, there is provided herein a process for eliminating oxygenates from a light hydrocarbon processing system. Such process may comprise removing oxygenates from an olefin stream 15 via an oxygenate adsorption unit 20 to provide a deoxygenated olefin stream 25, wherein the oxygenate adsorption unit becomes spent. In an embodiment, olefin stream 15 may comprise light hydrocarbons, e.g., C3-C5 olefins.
An olefin stream 15 that is fed to oxygenate adsorption unit 20 may be raw or untreated. In an embodiment, olefin stream 15 may be from a FCC unit (not shown). Olefin stream 15 may be contaminated with both water and various oxygenates. Olefin stream 15 may be saturated with water vapor. In an embodiment, olefin stream 15 may have a water content of at least 300 ppmw, or in the range from 300 to 500 ppmw.
The deoxygenated olefin stream 25 provided by oxygenate adsorption unit 20 may have an oxygenate content of not more than 5 ppmw, not more than 2 ppmw, or not more than 1 ppmw. In an embodiment, deoxygenated olefin stream 25 may have a water content of not more than 5 ppmw, not more than 2 ppmw, or not more than 1 ppmw. In an embodiment, deoxygenated olefin stream 25 and an isoparaffin stream 102 may be contacted with an ionic liquid catalyst 108 in an ionic liquid alkylation zone 120 under ionic liquid alkylation conditions to provide an ionic liquid alkylate (see, for example,
As a result of the step of removing oxygenates from olefin stream 15, oxygenate adsorption unit 20 may become spent. Prior to the regeneration of the spent oxygenate adsorption unit 20′, residual olefins 48 may be flushed therefrom for recovery. In an embodiment, the residual olefins 48 may be flushed from the spent oxygenate adsorption unit 20′ via an isobutane stream. In an embodiment, the isobutane stream for the recovery of the residual olefins 48 may have a temperature of not more than 150° F. (65.56 degree Celsius), or from 50 to 150° F. (10 to 65.56 degree Celsius). The residual (flushed) olefins can be combined with olefin stream 15, or may be fed to a FCC Gas Recovery Unit (not shown).
A spent oxygenate adsorption unit 20′may be regenerated via a regenerant stream 35 to provide an oxygenated regenerant stream 45 comprising the oxygenates, wherein the oxygenates of the oxygenated regenerant stream may be desorbed from spent oxygenate adsorption unit 20′ by the regenerant stream 35. In an embodiment, the regenerant stream 35 may have a temperature of at least 250° F. (121.1 degree Celsius), or from 300 to 600° F. (148.9 to 315.6 degree Celsius). The oxygenated regenerant stream may be contacted with a hydro-deoxygenation catalyst, in the presence of hydrogen gas in a hydro-deoxygenation zone 50 under hydro-deoxygenation conditions, to convert the oxygenates of the oxygenated regenerant stream to paraffins and water.
Typical hydro-deoxygenation conditions may comprise a temperature in the range from 350 to 650° F. (176.7 to 343.3 degree Celsius), or from 400 to 500° F. (204.4 to 260 degree Celsius); and a pressure in the range from 100 to 400 psig, or from 100 to 300 psig. The hydro-deoxygenation conditions may still further comprise an LHSV in the range from 2 to 20 hr−1, or from 2 to 10 hr−1. In an embodiment, the hydro-deoxygenation catalyst may comprise a noble metal selected from the group consisting of Pt, Pd, and combinations thereof.
The effluent from hydro-deoxygenation zone 50 may be referred to herein as a hydro-deoxygenation zone effluent. The hydro-deoxygenation zone effluent may be cooled to condense at least a portion of the water from the hydro-deoxygenation zone effluent to provide condensed water and a residual effluent comprising residual water. The condensed water may be permanently removed from the system, for example, by sending the condensed water to a waste water treatment unit. The residual effluent may be fed to a gravity settler 70. In an embodiment, the gravity settler 70 may comprise a coalescer.
The residual effluent may comprise the residual water, liquid hydrocarbons, and hydrogen gas. Via the gravity settler 70, the residual water, a liquid hydrocarbon phase, and hydrogen gas may each be separated from the residual effluent (see, for example,
A process for the preparation of ionic liquid alkylate will now be described with reference to
In ionic liquid alkylation zone 120, at least one isoparaffin and at least one olefin may be contacted with ionic liquid catalyst 108 under ionic liquid alkylation conditions. Anhydrous HCl co-catalyst or an organic chloride catalyst promoter (neither of which are shown) may be combined with the ionic liquid in ionic liquid alkylation zone 120 to attain the desired level of catalytic activity and selectivity for the alkylation reaction. Ionic liquid alkylation conditions, feedstocks, and ionic liquid catalysts that may be suitable for performing ionic liquid alkylation reactions in ionic liquid alkylation system 100 are described, for example, hereinbelow.
The effluent from ionic liquid alkylation zone 120 may be fed via line 122 to an ionic liquid/hydrocarbon (IL/HC) separator 130 for the separation of a hydrocarbon phase from the effluent. Non-limiting examples of separation processes that can be used for separating the hydrocarbon phase from the effluent include coalescence, phase separation, extraction, membrane separation, and partial condensation. IL/HC separator 130 may comprise, for example, one or more of the following: a settler, a coalescer, a centrifuge, a distillation column, a condenser, and a filter.
The hydrocarbon phase from IL/HC separator 130 may be fed via line 132 to an ionic liquid alkylate separation system 140. The hydrocarbon phase from IL/HC separator 130 may be referred to herein as an alkylation hydrocarbon phase. Ionic liquid alkylate separation system 140 may comprise at least one distillation unit (not shown). The alkylation hydrocarbon phase from IL/HC separator 130 may be fractionated via ionic liquid alkylate separation system 140 to provide an alkylate product 144, as well as HCl 146, a propane fraction 148, an n-butane fraction 150, and an isobutane fraction 152.
The instant specification further provides a process for eliminating oxygenates from a hydrocarbon processing system. With further reference to
With further reference to
With still further reference to
In an embodiment, the conversion of the oxygenates in oxygenated regenerant stream 45 to paraffins and water may involve heating the oxygenated regenerant stream to a temperature in the range from 350 to 650° F. (176.7 to 343.3 degree Celsius). Thereafter, hydrogen gas may be injected into the oxygenated regenerant stream at a location upstream from a hydro-deoxygenation zone 50. Thereafter, the oxygenated regenerant stream and hydrogen gas may be contacted with a hydro-deoxygenation catalyst in hydro-deoxygenation zone 50 under hydro-deoxygenation conditions. In an embodiment, the hydrogen gas may be injected at a rate in the range from 50 to 500 standard cubic feet per barrel (SCF/bbl) of the oxygenated regenerant stream 45. Typical hydro-deoxygenation conditions may comprise a temperature in the range from 350 to 650° F. (176.7 to 343.3 degree Celsius), a pressure in the range from 100 to 400 psig, and an LHSV in the range from 2 to 20 hr−1.
Ionic Liquid Catalyzed Alkylation
Ionic liquid catalysts may be useful for a range of hydrocarbon conversion reactions, including alkylation reactions for the production of alkylate, e.g., comprising gasoline blending components, and the like. In an embodiment, feedstocks for ionic liquid catalyzed alkylation may comprise various olefin- and isoparaffin containing hydrocarbon streams in or from one or more of the following: a petroleum refinery, a gas-to-liquid conversion plant, a coal-to-liquid conversion plant, a naphtha cracker, a middle distillate cracker, and a wax cracker, and the like.
Examples of olefin containing streams include FCC off-gas, coker gas, olefin metathesis unit off-gas, polyolefin gasoline unit off-gas, methanol to olefin unit off-gas, FCC light naphtha, coker light naphtha, Fischer-Tropsch unit condensate, and cracked naphtha. Some olefin containing streams may contain two or more olefins selected from ethylene, propylene, butylenes, pentenes, and up to C10 olefins. Such olefin containing streams are further described, for example, in U.S. Pat. No. 7,572,943, the disclosure of which is incorporated by reference herein in its entirety.
Examples of isoparaffin containing streams include, but are not limited to, FCC naphtha, hydrocracker naphtha, coker naphtha, Fisher-Tropsch unit condensate, and cracked naphtha. Such streams may comprise at least one C4-C10 isoparaffin. In an embodiment, such streams may comprise a mixture of two or more isoparaffins. In a sub-embodiment, an isoparaffin feed to the alkylation reactor during an ionic liquid catalyzed alkylation process may comprise isobutane.
Various ionic liquids may be used as catalysts for alkylation reactions involving olefins. Ionic liquids are generally organic salts with melting points below 100° C. (212 degree Fahrenheit) and often below room temperature. The use of chloroaluminate ionic liquids as alkylation catalysts in petroleum refining has been described, for example, in commonly assigned U.S. Pat. Nos. 7,531,707, 7,569,740, and 7,732,654, the disclosure of each of which is incorporated by reference herein in its entirety. Exemplary ionic liquids for use as catalysts in ionic liquid catalyzed alkylation reactions may comprise at least one compound of the general formulas A and B:
wherein R is H, methyl, ethyl, propyl, butyl, pentyl or hexyl, each of R1 and R2 is H, methyl, ethyl, propyl, butyl, pentyl or hexyl, wherein R1 and R2 may or may not be the same, and X is a chloroaluminate.
Non-limiting examples of chloroaluminate ionic liquid catalysts that may be used in alkylation processes according to embodiments of the instant invention include those comprising 1-butyl-4-methyl-pyridinium chloroaluminate, 1-butyl-3-methyl-imidazolium chloroaluminate, 1-H-pyridinium chloroaluminate, N-butylpyridinium chloroaluminate, and mixtures thereof.
Exemplary reaction conditions for ionic liquid catalyzed alkylation are as follows. The ionic liquid alkylation reaction temperature may be generally in the range from −40° C. to +250° C. (−40° F. to +482° F.), typically from −20° C. to +100° C. (−4° F. to +212° F.), and often from +4° C. to +60° C. (+39.2° F. to +140° F.). The ionic liquid alkylation reactor pressure may be in the range from atmospheric pressure to 8000 kPa. Typically, the pressure in the ionic liquid alkylation zone 120 is sufficient to keep the reactants in the liquid phase.
Residence time of reactants in ionic liquid alkylation zone 120 may generally be in the range from a few seconds to hours, and usually from 0.5 min to 60 min. A feed stream introduced into ionic liquid alkylation zone 120 may have an isoparaffin:olefin molar ratio generally in the range from 1 to 100, more typically from 2 to 50, and often from 2 to 20.
The volume of ionic liquid catalyst 108 in ionic liquid alkylation zone 120 may be generally in the range from 1 to 70 vol %, and usually from 4 to 50 vol %. The ionic liquid alkylation conditions may be adjusted to optimize process performance for a particular process or targeted product(s).
Numerous variations on the present invention are possible in light of the teachings described 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.
For the purposes of this specification and appended claims, unless otherwise indicated, all numbers expressing quantities, percentages or proportions, and other numerical values used in the specification and claims, are to be understood as being modified in all instances by the term “about.” Furthermore, all ranges disclosed herein are inclusive of the endpoints and are independently combinable. Whenever a numerical range with a lower limit and an upper limit are disclosed, any number falling within the range is also specifically disclosed.
Any term, abbreviation or shorthand not defined is understood to have the ordinary meaning used by a person skilled in the art at the time the application is filed. The singular forms “a,” “an,” and “the,” include plural references unless expressly and unequivocally limited to one instance.
All of the publications, patents and patent applications cited in this application are herein incorporated by reference in their entirety to the same extent as if the disclosure of each individual publication, patent application or patent was specifically and individually indicated to be incorporated by reference in its entirety.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to make and use the invention. Many modifications of the exemplary embodiments of the invention disclosed above will readily occur to those skilled in the art. Accordingly, the invention is to be construed as including all structure and methods that fall within the scope of the appended claims. Unless otherwise specified, the recitation of a genus of elements, materials or other components, from which an individual component or mixture of components can be selected, is intended to include all possible sub-generic combinations of the listed components and mixtures thereof.
The invention illustratively disclosed herein suitably may be practiced in the absence of any element which is not specifically disclosed herein.
