Catalyst composition

Abstract

Prior to reaction in the isomerization unit, the feed may be purified by contacting it with a composition comprising an alumina-based catalyst containing Group I or II cations or combinations thereof in the range of about 0% to about 20% by weight of Group I or II cations. In some embodiments, the alumina-based catalyst has one or more of the following characteristics: less than about 15% of the total pore volume in pores with a pore size less than 70 Å, less than 10% of the total pore volume in pores with a pore size greater than 350 Å, a median pore size by volume less than 120 Å, a water pore volume less than 1.10 cc / g, and a surface area greater than 160 m2 / g.

Description

[Technical field]

[0001] Ethylene can be oligomerized to higher molecular weight linear monoolefins. A variety of suitable oligomerization catalysts and processes are known. Such olefins include, for example, C4-C6 olefins useful as comonomers in plastics, e.g., LLDPE, or as synthetic lubricants. 10 range, useful as a detergent 12 ~C 20 The lower molecular weight olefins can be converted to sulfonates or alcohols by known commercial processes. 12 ~C 20 Olefins are used in detergent products. Lower molecular weight alcohols can be esterified with polyacids, such as phthalic acid, to form plasticizers for polyvinyl chloride.

[0002] A wide range of both linear alpha olefins and internal olefins can be produced by a two-stage process with an alpha olefin (AO) unit that oligomerizes ethylene and an isomerization / disproportionation (ID) unit that converts the alpha olefins to even and odd internal olefins. The excess C4-C 10 Light olefins and C 12+ Heavy olefins in the C range can be converted to internal olefins in the desired range (currently C 11 ~C 14 ) can be converted into these detergent ranges (C 11 ~C 14 ) odd and even linear internal olefins are fed to an oxo alcohol plant to produce C 12 ~C 15 Semi-linear alcohols can be produced. Most of the alcohols are sold to the detergent market, and some of the alcohols are ethoxylated.

[0003] The products from the AO unit can be used for the production of linear low density polyethylene (LLDPE), synthetic engine (motor) oils, and drilling mud formulations. However, the products from the AO unit can also be used as feed to an ID unit, which may include feed purification, olefin isomerization, olefin disproportionation, and product distillation.

[0004] During the isomerization process, the catalyst in the isomerization reactor becomes spent and the reactor catalyst can be replaced with fresh catalyst to return the process to full reactivity. Summary of the Invention

[0005] Prior to reaction in the isomerization unit, the feed can be purified by contacting with a composition having an alumina-based catalyst containing Group I or Group II cations or combinations thereof in the range of about 0% to about 20% by weight. The alumina-based catalyst has less than about 15% of the total pore volume in pores with a pore size of less than 70 Å, less than 10% of the total pore volume in pores with a pore size of more than 350 Å, a median pore size by volume of less than 120 Å, a water pore volume of less than 1.10 cc / g, and a surface area of ​​more than 160 m2 / g. In some embodiments, the Group I cation is potassium or sodium, and the soluble metal salt is selected from the group of potassium carbonate, potassium hydroxide, potassium oxide, potassium acetate, potassium chloride, potassium sulfate, potassium nitrate, potassium acetylacetone, potassium citrate, potassium oxalate, and mixtures thereof, or equivalents of sodium salts. The composition can be used as an adsorbent. [Brief description of the drawings]

[0006] [Figure 1] FIG. 1 is a simplified block flow diagram of one embodiment of a higher olefins process. [Diagram 2] FIG. 1 is a simplified block flow diagram of one embodiment of an isomerization / disproportionation process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] Embodiments described herein include processes for the oligomerization of ethylene to alpha olefins and for the production of internal olefins. The basic steps of the process include oligomerization, olefin isomerization, and olefin disproportionation (metathesis).

[0008] 1 shows a simplified block diagram of an oligomerization process 100. The oligomerization process 100 includes an oligomerization block 102, an olefin phase separator block 104, a first distillation block 106, an isomerization block 108, a disproportionation block 110 and a second distillation block 112.

[0009] Ethylene 2 is fed to oligomerization block 102. Ethylene is oligomerized in the presence of a non-Ziegler catalyst system (consisting of nickel and a complexing ligand) to produce C4 to C 20+ It preferentially forms a mixture of olefins, the majority of which are linear alpha olefins. The reaction can be carried out in a polar solvent (typically 1,4-butanediol) at about 90-120°C (194-248°F) and 90-140 atm (1320-2050 psia). The oligomerization reactor is a vessel type in which ethylene is bubbled through a catalyst-bearing solvent. The polar solvent is immiscible with the alpha olefin product and contains the catalyst material in solution. Once formed, the olefins have little chance of further reaction since most of them are no longer in contact with the catalyst. The oligomer formation generally follows the well-known Schultz-Flory equation:

[0010] The chain growth catalyst is generally prepared by dissolving a nickel compound in 1,4-butanediol with a bidentate ligand (e.g., diphenylphosphinobenzoic acid) and a catalyst activator (sodium borohydride). The nickel forms a complex with the ligand. After oligomerization has proceeded to the desired extent, the product 4 is removed from the reactor and sent to a phase separator 104 where the solvent / catalyst 8 and unconverted ethylene 6 are separated from the oligomers and recycled to the oligomerization block 102. The oligomer product mixture 10 undergoes a washing step to remove the catalyst and then passes through a first distillation block 106 to separate the alpha-olefins into the desired fractions. The oligomer product mixture 10 contains a normal geometric distribution of ethylene oligomers with high and low boiling range alpha-olefins.

[0011] The first distillation block 106 produces low boiling range alpha-olefins 12, high boiling range alpha-olefins 14, and product alpha-olefins 16. The low boiling range alpha-olefins 12 and high boiling range alpha-olefins 14 are sent to an isomerization block 108. The isomerization block 108 produces internal olefins 16 that are sent to a disproportionation block 110. The low boiling range alpha-olefins 12 and high boiling range alpha-olefins 14 are reacted over a heterogeneous catalyst to produce a range of corresponding internal isomers. The unisomerized alpha-olefins are kept to a minimum in the downstream disproportionation block 110 to reduce undesirable high molecular weight and very short chain products.

[0012] Disproportionation block 110 produces a product 18 containing odd and even internal olefins, which is sent to a second distillation block 112. The disproportionation reaction occurs over a heterogeneous catalyst containing cobalt, molybdenum, tungsten, or rhenium on an alumina or silica substrate. Metathesis allows for the disproportionation of low and high boiling range internal olefins to a range of more useful molecular weight olefins. The disproportionation reaction is equilibrium controlled and the conversion is a function of temperature and reactant concentration.

[0013] The second distillation block 112 produces low boiling range internal olefins 20, high boiling range internal olefins 22, and internal olefin product 24. The low boiling range internal olefins 20 are recycled to the disproportionation block 110 and the high boiling range internal olefins 22 are recycled to the isomerization block 108.

[0014] In some embodiments, the mixture of low boiling range alpha-olefins 12 and high boiling range alpha-olefins 14 fed to isomerization block 108 is a portion of the product from oligomerization block 102 that is not intended for the alpha-olefins market.

[0015] 2 is a block diagram of an isomerization / disproportionation process 200. In some embodiments, the isomerization / disproportionation process includes, but is not limited to, four major unit operations: a feed purification unit 202, an olefin isomerization unit 204, an olefin disproportionation unit 206, and a product distillation unit 208.

[0016] The isomerization / disproportionation process 200 randomizes the carbon chain length attached to a set of carbon-carbon double bonds. The randomization is accomplished via the olefin isomerization unit 204. The olefin isomerization reaction moves the position of the carbon-carbon double bonds in the molecule, but does not change the number of moles passing through the reactor. Similarly, the disproportionation unit 206 fragments and then recombines the olefins passing through the disproportionation unit 206, but does not change the number of moles. That is, the equipment of the isomerization / disproportionation process 200 requires the conservation of moles as well as the conservation of mass.

[0017] purification Feed purification unit 202 removes catalyst poisons that may deactivate the catalyst in either the olefin isomerization unit 204 or the olefin disproportionation unit 206. The feed to feed purification unit 202 may include streams from oligomerization block 102 that include butenes 210, lights feed 212 (shown in FIG. 1 as Stream 12), and heavy ends feed 216 (shown in FIG. 1 as Stream 14). The catalyst poisons may include, but are not limited to, solvent decomposition products (which may contain oxygen), water, peroxides, carbonyls, and ligand decomposition products (most of which may contain phosphorus as phosphines).

[0018] In some embodiments, the heavy feed 216 is 12~40+ Containing alpha olefins, the lights feed 212 may comprise a mixture of 1-hexene, 1-octene, and 1-decene. The mixed feed 214 may include olefins stripped from various fixed bed operations as well as olefin washes used in those operations.

[0019] The butenes 210, the lights feed 212, the mixed feed 214, and the heavy feed 216 may be combined with a heavy recycle stream 218 from the product distillation unit 208. The heavy recycle stream 218 is made up of the high molecular weight olefins (typically C 19+ ) may be included.

[0020] The chemistry of the isomerization / disproportionation process 200 has the complication that the average carbon number of the alpha olefins entering the isomerization / disproportionation process 200 must match the average carbon number of the isomerization / disproportionation product + bleed. Calculations based on the flow rates and estimated carbon numbers of the isomerization / disproportionation product and bleed control the alpha olefin feed rate and feed carbon number requirements. Calculations using the lights feed 212 and mixed feed 214, and the heavy recycle stream 218 as calculation inputs calculate the flow rates of butenes 210 and heavy feed 216 required to meet the mass and carbon number requirements.

[0021] In some embodiments, the feed purification unit 202 may include one or more butene desiccants, one or more purification beds, and one or more light feed desiccants, or any combination thereof. The butenes 210 may pass through a butene desiccant containing adsorbent, such as, but not limited to, molecular sieves or alumina, typically 3A molecular sieves, before mixing with the light feed 212, the mixed feed stream 214, the heavy feed 216, and the heavy recycle stream 218. In other embodiments, the butene desiccants may use any type of adsorbent, particularly molecular sieves. The adsorption capacity of the feed purification unit 202 can be controlled by the cycle time and lifetime of the purification adsorbent in the feed purification unit 202. In this case, the cycle time refers to the time between regenerations, and the lifetime refers to the actual time the adsorbent has been in the unit. The operational intent is to maintain the adsorption capacity at a very high level so that the conversion of the isomerization / disproportionation process 200 remains high and stable at all times. One skilled in the art would be able to determine the frequency and process for regenerating feed purification system 202 and when to replace the adsorbent within feed purification system 202 .

[0022] In some embodiments, the lights feed 212 is sent to a lights feed desiccant before mixing with the butenes 210, the mixed feed 214, the heavy feed 216, and the heavy recycle stream 218. The lights feed desiccant may contain an adsorbent such as, but not limited to, molecular sieves or alumina, typically 4A molecular sieves.

[0023] The combined olefin stream of butenes 210, light feed 212, mixed feed 214, and heavy feed 216 is combined with heavy recycle stream 218 before entering one or more purification (P) beds. The combined olefin stream flows from the bottom to the top of one or more purification beds. The purification beds can be operated at temperatures ranging from about 110 to about 150° C., in some embodiments from about 80 to about 140° C., and at pressures ranging from about 1 to about 25 bar, in some embodiments from about 3 to about 20 bar. In some embodiments, there are two purification beds to maintain the efficiency of the feed purification unit 202. These purification beds may be operated such that one purification bed is in use and the other is in regeneration. In other embodiments, there may be two purification beds operated in series with a third purification bed in regeneration. In some embodiments, the heavy recycle stream 218 may bypass the feed purification unit 202.

[0024] One or more purification beds may include one or more layers of adsorbent. These layers may have different compositions, and one of ordinary skill in the art would be able to determine the amount of each adsorbent and the type of adsorbent for each layer.

[0025] In some embodiments, the adsorbent for the purification bed may be an alumina shaped catalyst or molecular sieve, or an alumina-based catalyst or molecular sieve containing about 5% to about 20% by weight of Group I or Group II cations, or a combination thereof. The alumina may be alpha, beta, theta, or gamma alumina. The alumina-based catalyst may contain, in addition to alumina, small amounts of other inorganic oxides, such as titania, zirconia, silica, phosphorus, and the like. The alumina material may contain small amounts of other components that do not substantially affect the properties of the adsorbent. Thus, the alumina-based catalyst may consist essentially of alumina. The phrase "consisting essentially of" as used herein and in the claims with respect to the composition of the alumina-based catalyst means that the alumina-based material must contain alumina and may contain other components, provided that such other components do not substantially affect the adsorption properties of the final adsorbent composition.

[0026] Alumina-based catalysts that can be employed in the practice of the present invention may be obtained commercially from catalyst suppliers or may be prepared by a variety of processes.

[0027] The properties of an alumina-based catalyst for a refining bed can be defined as follows: Pore ​​volume in pores with a pore diameter less than 70 Å: less than about 15% of the total pore volume, less than about 12% of the total pore volume, less than about 10% of the total pore volume. Pore ​​volume in pores with a pore diameter of more than 350 Å: less than about 10% of the total pore volume, less than 8% of the total pore volume, less than about 6% of the total pore volume.

[0028] The median pore size (median Pore ​​diameter (MPD): less than 120 Å, approximately 80 to approximately 110 Å. Water pore volume: less than 1.10 cc / g, about 0.65 to about 1.10 cc / g, about 0.75 to about 1.0 cc / g.

[0029] References herein to pore size distribution and pore volume of an alumina-based catalyst are to such properties as determined by mercury intrusion porosimetry. Measurement of pore size distribution of an alumina-based catalyst is by any suitable mercury porosimeter capable of operating in the pressure range between atmospheric pressure and about 60,000 PSI, using a contact angle of 140 with a mercury surface tension of 474 dynes / cm at 25° C. Pore volume is defined as the total volume using mercury intrusion as measured between atmospheric pressure and a pressure of about 60,000 psia.

[0030] Surface area: Approximately 160 to 400 m 2 / g, about 200~350m 2 / g, approx. 225~325m 2 / g. Surface area is measured by nitrogen adsorption using the well-known BET method, which is described in detail by Brunauer, Emmet and Teller in J. Am. Chem. Soc. 60 (1938) 309-316, which is incorporated herein by reference.

[0031] In some embodiments, the alumina-based catalyst comprises a Group I or Group II cation or a combination thereof. In some embodiments, the Group I cation is potassium or sodium, and the Group I cation is selected from the group of potassium carbonate, potassium hydroxide, potassium oxide, potassium acetate, potassium chloride, potassium sulfate, potassium nitrate, potassium acetylacetonate, potassium citrate, potassium oxalate, and mixtures thereof, or equivalents of sodium salts. The amount of metal may range from about 0% to about 20% by weight, about 7.5% to about 15% by weight. In some embodiments, the metal may be incorporated into the alumina-based catalyst by any suitable means or method known to those skilled in the art. For example, the metal component may be co-mixed with the alumina of the alumina-based catalyst during the formation of the agglomerated particles of the alumina-based catalyst, or the metal component may be incorporated into the alumina-based catalyst by impregnation, or the metal may be incorporated into the alumina-based catalyst by a combination of methods. The metal component is incorporated into the alumina-based catalyst in an amount to provide a concentration of the metal component as described above. The alumina-based catalyst having metal components incorporated therein may be dried or calcined, or both, according to known methods to provide the final catalyst.

[0032] In some embodiments, the butene desiccant, light feed drying and refinery beds are regenerated on a time basis that may differ for each unit. One skilled in the art will be able to determine when to regenerate the butene desiccant, light feed drying and refinery beds. One skilled in the art will also know that the regeneration procedures for the butene desiccant and light feed drying agent typically constitute the molecular sieve regeneration process. Regeneration of the butene desiccant and light feed drying agent involves evaporating residual hydrocarbons from the butene desiccant and light feed drying agent. Regeneration of the refinery beds involves burning off any residual hydrocarbons, purging oxygen and water after burning, and cooling the refinery beds in preparation for return to use.

[0033] The regeneration process for the refinery bed comprises converting butenes 210, lights feed 214, heavies feed 216, and heavies recycle stream 218 in the refinery bed into light feed 212 or an intermediate recycle stream, typically C4-C 2H 2 O 3 from product distillation unit 208. 11 In another embodiment, the replacement fluid is the C stream from the product distillation unit 208. 15 ~C 18 The bed may then be stripped with hot nitrogen (about 260 to about 290° C.) to vaporize any recoverable hydrocarbons on the bed. A controlled combustion of about 1 to 5% by volume oxygen in nitrogen is used to burn off the residual hydrocarbons. Temperatures can be as high as about 450° C. in the bed. The bed is then flooded with 450° C. nitrogen and cooled to less than about 135° C. in a nitrogen purge. The bed can now be considered regenerated and ready to be put back on the production line. One skilled in the art would be able to modify the regeneration procedure as needed depending on the butene desiccant, the light feed desiccant, and the contents of the refinery bed.

[0034] As the frequency of regeneration of the refinery bed decreases, the isomerization catalyst performance decreases. Since the adsorption efficiency is directly related to the surface area of ​​the adsorbent, each regeneration reduces the surface area of ​​the adsorbent slightly, with a corresponding decrease in adsorption efficiency. Eventually, the surface area of ​​the adsorbent decreases sufficiently that the exhausted adsorbent must be discarded and replaced with a new one. A given loading of refinery bed adsorbent can perform its function for several years, e.g., 4-7 years.

[0035] The exhaust streams of the active refinery bed and the light feed drying agent are combined and exit the feed refinery unit 202 as refinery feed 220 and are fed to the isomerization unit 204 .

[0036] isomerization The isomerization unit 204 may include multiple reactors operating in series. The isomerization unit 204 takes an alpha olefin product and moves the carbon-carbon double bonds from the alpha position to other positions along the carbon chain length, while also achieving an equilibrium distribution of carbon-carbon double bonds along the carbon chain length. Olefin isomerization creates a mixture of carbon chain lengths attached to carbon-carbon double bonds. The olefins exiting the isomerization unit 204 are the isomerization product 222.

[0037] In some embodiments, the isomerization unit 204 includes four fixed bed isomerization reactors, with three reactors operating in series, parallel or combination at any one time, and the fourth reactor being refurbished. In some embodiments, the isomerization reactor with the oldest (longest catalyst on cycle) catalyst charge is rotated into the first isomerization reactor position. The oldest catalyst charge is then placed into the second isomerization reactor position, and the newest catalyst charge is placed into the third isomerization reactor position. When a newly refurbished isomerization reactor is brought onto the production line, the isomerization reactor positions are adjusted accordingly. In some embodiments, the isomerization reactors are operated in a downflow direction.

[0038] In some embodiments, the reactor with the oldest isomerization catalyst charge is rotated to the first isomerization reactor position, i.e., receives the refined feed 220. The refined feed 220 may include a heavy recycle stream 218 that is at least 50 percent isomerized. The use of multiple isomerization reactors in series allows the olefin mixture to be isomerized to 100%.

[0039] The one or more isomerization reactors may include one or more layers of isomerization catalyst. These layers may have different compositions, and one of ordinary skill in the art would be able to determine the amount of each catalyst and type of catalyst for each layer. In some embodiments, a guard bed layer of alumina may be disposed above and below the isomerization catalyst. The alumina guard bed layer may be one or more layers of about 10-20% of the total amount of isomerization catalyst. The guard bed layer may include alumina of various pore sizes. In some embodiments, the guard bed may have a median pore size by volume ranging from about 115 to about 200 Å.

[0040] In some embodiments, the isomerization catalyst for the isomerization reactor may be an alumina-based catalyst or a molecular sieve. The alumina may be alpha, beta, theta, or gamma alumina. The alumina-based catalyst may contain, in addition to alumina, small amounts of other inorganic oxides, such as titania, zirconia, silica, phosphorus, and the like. Although the alumina-based catalyst may contain small amounts of other components that do not substantially affect the catalytic properties, the alumina-based catalyst should generally consist essentially of alumina. The phrase "consist essentially of" as used herein and in the claims with respect to the composition of the alumina-based catalyst means that the alumina-based catalyst must contain alumina and may contain other components, provided that such other components do not substantially affect the catalytic properties of the final catalyst composition.

[0041] Alumina-based catalysts may be obtained commercially from catalyst suppliers or may be prepared by a variety of processes.

[0042] The properties of alumina-based catalysts for isomerization catalysts can be defined as follows using the test methods described above: Pore ​​volume in pores with a pore diameter of less than 70 Å: less than about 5% of the total pore volume, about 5% to about 0.01% of the total pore volume, about 3% to about 0.01% of the total pore volume. Pore ​​volume in pores with a pore diameter of more than 350 Å: less than 10% of the total pore volume, less than about 8% of the total pore volume, less than about 6% of the total pore volume. Median pore diameter (MPD), which corresponds to the median pore diameter by volume: less than 200 Å, about 90 to about 180 Å, or about 105 to about 165 Å. Water pore volume: less than 1.20cc / g, about 0.79 to about 1.10cc / g. Surface area: Approximately 100 to 400 m 2 / g, about 150~350m 2 / g, about 170~300m 2 / g. The pore size range of the most abundant 66% pores from the Hg PSD method from 60 to 6 K (PSD width 66% (60k to 6k)): about 10 to about 100 Å.

[0043] In some embodiments, the alumina-based catalyst may contain Group I or Group II cations or a combination thereof. In some embodiments, the Group I cation is potassium or sodium, and the Group I cation is selected from the group of potassium carbonate, potassium hydroxide, potassium oxide, potassium acetate, potassium chloride, potassium sulfate, potassium nitrate, potassium acetylacetone, potassium citrate, potassium oxalate, and mixtures thereof, or equivalents of sodium salts. The amount of metal may range from about 0% to about 20% by weight, about 0.5% to about 15% by weight. In some embodiments, the metal may be incorporated into the alumina-based catalyst by any suitable means or method known to those skilled in the art. For example, the metal component may be co-mixed with the alumina of the alumina-based catalyst during the formation of the agglomerated particles of the alumina-based catalyst, or the metal component may be incorporated into the alumina-based catalyst by impregnation, or the metal may be incorporated into the alumina-based catalyst by a combination of methods. The metal component is incorporated into the alumina-based catalyst in an amount to provide a concentration of the metal component as described above. The alumina-based catalyst having a metal component incorporated therein can be dried or calcined, or both, according to known methods to provide an isomerization catalyst.

[0044] In some embodiments, the alumina-based catalyst or cation-impregnated isomerization catalyst is further impregnated with about 0.5 to about 15 weight percent of a metal selected from Group I metal, Group II metal, or a combination thereof. In some embodiments, the metal may be impregnated as a liquid or a eutectic alloy. The eutectic alloy may be a sodium potassium eutectic. In one embodiment, the process of impregnating the alumina-based catalyst or isomerization catalyst may include the following steps: First, the alumina-based catalyst or isomerization catalyst is heated in a vessel to 700°F to 900°F for about 12 to 18 hours. Next, the alumina-based catalyst or isomerization catalyst is transferred to a mixing vessel. When the temperature of the alumina-based catalyst or isomerization catalyst is cooled to about 500°F in the mixing vessel, NaK is impregnated into the alumina-based catalyst or isomerization catalyst. In some embodiments, the combination of 5 wt. % potassium on the isomerization catalyst with an additional 5 wt. % NaK results in a catalyst run time that is about 70% longer (14-24 days) than previous versions of the isomerization catalyst that had only NaK. During the impregnation and mixing stage, the mixing vessel is kept as close to isothermal as possible at the desired set point in the range of 400-500°F for an impregnation time of 4-6 hours. The temperature is controlled by using hot oil flowing through the mixing vessel jacket. Production of the isomerization catalyst under isothermal conditions results in a further increase in run time of 80% (24 days to 43 days). Although impregnation of a NaK eutectic alloy has been described, the same procedure can be used to impregnate other metals or metal alloys onto alumina-based catalysts or cation-impregnated isomerization catalysts.

[0045] During the isomerization process, the catalyst in the isomerization unit 204 is deactivated. The isomerization catalyst contains highly reactive (pyrophoric) metals. This means that a reconditioning procedure is performed to ensure safe disposal. Reconditioning prepares the catalyst to be discarded from one of the isomerization reactors. The reconditioning procedure can include the following steps: hydrocarbon washing the catalyst, deactivating the catalyst, water washing the catalyst, and discarding the catalyst.

[0046] Hydrocarbon Washing: When the isomerization reactor is ready to be taken off-line for overhaul, full range olefins (C4-C 40+) to high temperature olefins (C4-C 11 Or C 15 ~C 18 ) (hydrocarbon wash). In some embodiments, the feed to the reactor that is being taken off line is stopped. The hot olefin wash washes the reactor by entering the top of the reactor, passing through the reactor and out the bottom and back to the process piping. The hot olefin wash removes any water from the header and heats the header to the hot olefin wash temperature, about 121° C. The hot olefin wash is flushed through the isomerization reactor for about 2.5 hours. Once the hydrocarbon wash is complete, the off line isomerization reactor is isolated from the process.

[0047] Catalyst Deactivation: Once the isomerization reactor is taken off-line and flushed with hot olefins, the hot olefins left in the isomerization reactor and the olefins stored in the deactivated HC storage vessel are cooled. The deactivation manifold is aligned in an upflow manner so that the olefins flow from the deactivated HC storage vessel into the bottom of the isomerization reactor and out the top of the I reactor and back into the deactivated HC storage vessel. A circulation flow is established through the I reactor, which also passes through a cooling water exchanger to cool the reactor and the deactivated HC storage vessel. Once the contents of the reactor and the deactivated HC storage vessel have cooled down to a maximum of about 100°F, the system is ready for deactivation. Once cooled, a small amount of water is injected into the circulation flow. This slowly deactivates the NaK as the water level slowly rises in the reactor and eventually overflows into the deactivated HC storage vessel. This marks the end of the deactivation stage.

[0048] Water Wash: The water wash step provides another opportunity for water to come into contact with any pyrophoric materials in the off-line I reactor and to flush NaOH and KOH from the isomerization reactor. The water pump is then started and the wash water flow valve is fully opened to flush through the inerting header for approximately 15 minutes. The inerting header bypass valve is then closed and the wash water flow is aligned through the bottom of the I reactor and out the top into the inerting HC surge vessel. When the level in the inerting HC surge vessel reaches a predetermined level, the wash water flow and water pump are stopped. A predetermined level of water is discharged from the bottom of the I reactor into the inerting HC surge vessel to create a vapor space in the I reactor. Sparge nitrogen is then aligned to the bottom of the I reactor and the associated flow control valve is opened wide to sparge nitrogen into the bottom of the I reactor and out the top of the reactor into the inerting HC surge vessel where it is vented to the vent header system. This sparge is continued for one hour to help purge the hydrocarbon vapors. After one hour, the first nitrogen sparge is stopped and the inerted HC surge vessel level controller is aligned to allow drainage at the predetermined level from the bottom boot. The water pump is restarted and the wash water is allowed to flow for approximately six hours. The wash water flows through the bottom of the I-reactor into the inerted HC surge vessel where it is discharged through the solids collection sump to the sewer. Once the target total flow rate is achieved, the water pump is stopped. The inerted HC surge vessel level control valve closes and after a period of time, the shutoff valve also closes to ensure positive shutoff.

[0049] These steps may be repeated for a second nitrogen sparge and a second water wash, a third nitrogen sparge and a third water wash, and a fourth nitrogen sparge and a fourth water wash.

[0050] Drying / Dumping: The isolation valve is closed to retain the water in the I reactor. The water pump is stopped and the I reactor pressure is increased. The bottom discharge valve is opened and the catalyst and water are dumped into the catalyst trailer. The I reactor (and associated parts) is then sparged with nitrogen and washed with water. The I reactor is then dried in preparation for loading a new catalyst.

[0051] Disproportionation The isomerization product 222 is combined with a lights recycle stream 234 and an intermediate recycle stream 224 to form a disproportionation feed 226. The disproportionation feed 226 enters the disproportionation unit 206 which produces a disproportionation product 228. The disproportionation (metathesis) unit 206 allows for the disproportionation of low and high boiling range internal olefins into a range of more useful molecular weight olefins, with the total number of molecules remaining essentially unchanged.

[0052] Olefin metathesis involves breaking double bonds on different olefin molecules and then recombining the fragments, for example: 5 R1CH=CHR2+5 R3CH=CHR4⇔ R1CH=CHR3+R1CH=CHR4+R2CH=CHR4+R2CH=CHR3 R1CH=CHR1+R2CH=CHR2+R4CH=CHR4+R3CH=CHR3 +R1CH=CHR2+R3CH=CHR4

[0053] The resulting product is a statistical distribution of "arms" added to the original double bond.

[0054] For example, a C4 olefin and a C24 olefin can be disproportionated to two C14 olefins. The olefin disproportionation reaction is equilibrium controlled and the conversion is a function of temperature and reactant concentration.

[0055] The disproportionation may be carried out either batchwise or continuously using a fixed or fluidized catalyst bed or any other moving catalyst contacting process. The preferred reaction conditions for the disproportionation process, e.g., temperature, pressure, flow rate, etc., may vary somewhat depending on the particular catalyst composition, the particular feed olefin, the desired products, etc. The process is typically carried out at temperatures in the range of 150-400°C and pressures in the range of 1-50 bar. More preferably, temperatures in the range of 200-300°C are used.

[0056] The operable range of contact times for the disproportionation reaction depends primarily on the operating temperature and the activity of the catalyst, which is affected by surface area, promoter concentration, activation temperature, etc. In general, the product distribution does not change dramatically with variation in contact time. Shorter contact times are usually associated with higher temperatures, but if higher amounts of higher molecular weight products are desired, a suitable combination of contact time and temperature is selected. By properly selecting the conditions and contact times, very high conversions to the desired products can be obtained.

[0057] Disproportionation unit 206 may include multiple disproportionation reactors. The number of disproportionation reactors may be determined by one of ordinary skill in the art. In some embodiments, disproportionation unit 206 includes five disproportionation reactors, with four disproportionation reactors operating in parallel while the fifth disproportionation reactor is being regenerated. Once a disproportionation reactor completes regeneration, it is placed in the production line, and the disproportionation reactor that has been on the production line the longest goes into regeneration. In other embodiments, multiple reactors may be placed in series. The multiple reactors do not have to be uniformly sized.

[0058] In some embodiments, the olefin volumetric flow rate through a given disproportionation reactor depends on the time the disproportionation reactor has been on-line since the last regeneration, i.e., a freshly regenerated disproportionation catalyst receives a proportionately higher olefin volumetric flow rate than a disproportionation catalyst that has had a longer time on-line. In other embodiments, the disproportionation feed is evenly distributed to the disproportionation reactors on the production line.

[0059] The reactor in disproportionation unit 206 is packed with a disproportionation catalyst. Embodiments of disproportionation catalysts can be found in U.S. Pat. Nos. 4,754,099, 4,962,263, 4,996,386, 4,956,516, and EP 0 319 065.

[0060] In some embodiments, the disproportionation catalyst may include a molybdenum catalyst along with an alumina-based catalyst.

[0061] The properties of the disproportionation catalyst can be defined as follows: Pore ​​volume in pores with a pore diameter less than 350 Å: less than about 10% of the total pore volume, less than 8% of the total pore volume, less than about 6% of the total pore volume. Median pore diameter (MPD) corresponding to the median pore diameter by volume: about 55 to about 95 Å, about 60 to about 80 Å. Water pore volume: greater than about 0.5 and less than about 1.0 cc / g, about 0.55 to about 0.85 cc / g, about 0.60 to about 0.82 cc / g. Surface area: approx. 200m 2 / g, 240m 2 / g, 260m 2 / g super.

[0062] In some embodiments, the disproportionation catalyst may also contain less than about 12 wt.% of a Group 6 metal and about 0 to about 10 wt.% of a Group 14 metal. The Group 6 metal may be selected from the group consisting of molybdenum, tungsten, and mixtures thereof. In some embodiments, the amount of molybdenum ranges from less than about 12 wt.%, from about 2 to about 10 wt.%, or from about 4 to about 8 wt.%. The Group 14 metal may be silicon. In some embodiments, the disproportionation catalyst does not contain silicon. In other embodiments, the disproportionation catalyst may contain about 1 to about 5 wt.% of silicon.

[0063] The disproportionation catalyst may generally be prepared according to conventional methods such as the impregnation method, in which the support is impregnated with a solution of the metal, the coprecipitation method, in which the support compound and the metal are precipitated simultaneously, or the co-mulling method, in which dry powders are mixed with a suitable extrusion aid such as water and extruded, or a combination thereof.

[0064] In some embodiments, the metal and / or silicon may be incorporated into the alumina-based catalyst by any suitable means or method known to those skilled in the art. For example, the metal and / or silicon component may be co-kneaded with the alumina of the alumina-based catalyst during the formation of the agglomerated particles of the alumina-based catalyst, or the metal and / or silicon component may be incorporated into the alumina-based catalyst by impregnation, or the metal and / or silicon may be incorporated into the alumina-based catalyst by a combination of methods. The metal and / or silicon component is incorporated into the alumina-based catalyst in an amount to provide the concentration of the metal and / or silicon component as described above. The alumina-based catalyst with the incorporated metal component may be dried or calcined, or both, according to known methods to provide a disproportionation catalyst.

[0065] Since disproportionation shifts the double bonds toward one end of the resulting olefins, the disproportionation product 228 is not in equilibrium with respect to double bond distribution. Since alpha olefins disproportionate to lower molecular weight olefins, i.e., "lights," the alpha olefins present in the disproportionation feed 226 should be minimized, or excessive amounts of "lights" (ethylene and propylene) may be formed. Ethylene and propylene can polymerize over the disproportionation catalyst, thereby inducing the formation of coke thereon that reduces its reactivity.

[0066] The disproportionation catalyst may be activated multiple times to extend its useful life. In some embodiments, a possible activation process includes the following steps: a) a hot wash (up to about 250°F (about 120°C)) using an intermediate recycle stream consisting of C4-C10 internal olefins is performed by flowing it through the catalyst bed to remove most of the heavy hydrocarbons and / or coke, b) the hot recycle stream is then removed from the catalyst bed using nitrogen pressure, c) the catalyst bed is then exposed to hot nitrogen (up to about 550°F (288°C)) using a stripping step to evaporate the residual hydrocarbons and water, d) the temperature (up to about 750-850°F (400-455°C)) and oxygen concentration (about 0.4 to about 0.8, up to 2% by feeding air) are removed via combustion, and e) the oxygen flow is stopped, resulting in hot nitrogen circulating in the bed. In some embodiments, an external desiccant utilizing molecular sieves can be used to dry the nitrogen and remove water formed during combustion. The external desiccant ensures that moisture is removed from the catalyst bed before it is returned to use. In some embodiments, higher temperatures may be used depending on the nature of the coking.

[0067] To minimize the accumulation of ethylene and propylene in the ID unit, these "lights" may be vented. Alpha olefins and dimerized branched olefins are relatively unreactive in the disproportionation unit 206 and accumulate in the heavy recycle stream, reducing its reactivity. To maintain reasonable reactivity, these unreactive olefins may be purged from the distillation unit 208.

[0068] The disproportionation product 228 (combined from the multiple reactors) is sent from the disproportionation unit 206 to the product distillation unit 208. In some embodiments, the product distillation unit includes several distillation columns to provide a slate of olefin products along with a recycle stream to either the disproportionation unit 206 or the feed purification unit 202. In some embodiments, the recycle stream may also be sent to the isomerization unit 204. The lights recycle stream 234 and the intermediate recycle stream 224 may be recycled to the disproportionation unit 206, and the heavies recycle stream 218 may be recycled to the feed purification unit 202.

[0069] In some embodiments, the product distillation unit 208 produces C11-12 olefins 230 and C15-16 olefins 232. In other embodiments, the product distillation unit 208 may be designed by one skilled in the art to also produce products including, but not limited to, C80 olefins, which is a mixture of C8, C9, and C10 internal olefins, C10 olefins, C15-16 olefins, and C15-18 olefins, which is a mixture of C15, C16, C17, and C18 internal olefins.

[0070] In some embodiments, there may be additional internal recycle streams from within olefin disproportionation unit 206. These recycle streams may include a light recycle stream (predominantly C4 and C5 olefins, but may include up to C10 olefins) and an intermediate recycle stream (C4-10 internal olefins).

[0071] Although several embodiments of the present disclosure have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible without substantially departing from the teachings of the present disclosure. Accordingly, such modifications are intended to be included within the scope of the present disclosure as defined in the claims.

Claims

1. A composition comprising an alumina-based catalyst containing in the range of about 0% to about 20% by weight of a Group I or Group II cation, or a combination thereof.

2. 10. The composition of claim 1, wherein the alumina-based catalyst has less than about 15% of its total pore volume in pores with a pore diameter of less than 70 Å.

3. 2. The composition of claim 1, wherein the alumina-based catalyst has less than 10% of its total pore volume in pores with a pore diameter greater than 350 Å.

4. 10. The composition of claim 1, wherein the alumina-based catalyst has a median pore diameter by volume of less than 120 Å.

5. 10. The composition of claim 1, wherein the alumina-based catalyst has a water pore volume of less than 1.10 cc / g.

6. The alumina catalyst is 160 m ２ 13. The composition of claim 1 having a surface area of ​​greater than 1.0 μm / g.

7. 2. The composition of claim 1, wherein the Group I cation is potassium or sodium and the soluble metal salt is selected from the group of potassium carbonate, potassium hydroxide, potassium oxide, potassium acetate, potassium chloride, potassium sulfate, potassium nitrate, potassium acetylacetonate, potassium citrate, potassium oxalate, and mixtures thereof, or equivalents of the sodium salts.

8. The composition of claim 1 for use as an adsorbent.

Images