Apparatus for dehydrogenating normal paraffins to olefins

Abstract

The utility model relates to a device for dehydrogenating normal paraffin into olefin, for the production of linear alkylbenzene, the device includes: deoxidation unit (110), it communicates with triglyceride feed pipeline (105), C9 to C14 pipeline (115) and C14+ pipeline (120), wherein C9 to C14 pipeline (115) and C14+ pipeline (120) communicate with deoxidation unit (110), first adsorbent bed, which contains the first adsorbent including alkali metal cation or alkaline earth metal cation exchange X-zeolite, communicate with first pipeline (130), purification pipeline (145), which communicates with the first adsorbent bed, dehydrogenation unit (150), which communicates with purification pipeline (145), dehydrogenation pipeline (155), which communicates with dehydrogenation unit (150).

Description

[0001] This application is a divisional application of Chinese utility model patent application No. 202420660440.9, filed on April 2, 2024, entitled "Apparatus for Dehydrogenating n-Alkanes into Olefins".

[0002] Priority Statement

[0003] This application claims priority to U.S. Provisional Patent Application Serial No. 63 / 504,884, filed May 30, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0004] This invention relates to an apparatus for dehydrogenating n-chain alkanes into olefins, used in the production of straight-chain alkylbenzenes. Background Technology

[0005] Straight-chain alkylbenzenes are those with the formula C6H5C n H 2n+1 Organic compounds. While the alkyl carbon number "n" can have any practical value, detergent manufacturers prefer alkylbenzenes to have an alkyl carbon number in the range of 9 to 16, and preferably in the range of 9 to 14. These specific ranges are typically required when alkylbenzenes are used as intermediates in the production of surfactants for detergents. An alkyl carbon number in the range of 9 to 14 conforms to the specifications of the detergent industry.

[0006] Because surfactants derived from alkylbenzenes are biodegradable, alkylbenzene production has grown rapidly since its initial use in detergent production in the 1960s. The linearity of the alkane chain in alkylbenzenes is crucial to the biodegradability of the material and its effectiveness as a detergent. The primary factor determining the final linearity of alkylbenzenes is the linearity of the alkane component.

[0007] While detergents made using alkylbenzene-based surfactants are biodegradable, previous methods for producing alkylbenzene were not based on renewable sources. Specifically, alkylbenzene is currently produced from kerosene refined from crude oil extracted from the earth. Growing environmental biases against fossil fuel extraction and economic concerns about depleting fossil fuel deposits may support the use of alternative sources of biodegradable surfactants in detergents and other industries.

[0008] C9-C14 alkanes derived from vegetable oils or animal fats contain contaminants that can poison dehydrogenation catalysts. These contaminants can also cause discoloration of straight-chain alkylbenzenes and straight-chain alkylbenzene sulfonates. Contaminants may include aromatic compounds, light oxygenated compounds, fatty acids, and fatty acid esters. These contaminants need to be removed before dehydrogenating C9-C14 alkanes.

[0009] Therefore, it is desirable to provide the dehydrogenation unit with purified C9- to C14 alkanes from renewable, easily processable triglycerides and fatty acids derived from vegetable oils, animal oils, nut oils, and / or seed oils. Palm kernel oil, coconut oil, and babassu oil have a high desired range of C9- to C14 n-chain alkanes, consistent with the alkyl carbon number range required by the detergent industry. These renewable sources also have substantial nC16- to nC18 feedstocks, and it is desirable to convert those feedstocks into nC9- to nC14 feedstocks with high single-pass yields. These nC9- to nC14 intermediates can be used to ultimately prepare linear alkylbenzene-type detergents through additional process steps. It is further desirable that the resulting nC9- to nC14 alkanes be linear products with minimal branched isomers. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of one embodiment of the method for producing alkylbenzene from triglycerides according to the present invention.

[0011] Figure 2 The graph is based on the mass percentage of n-chain alkanes versus deoxygenation temperature from Example 2. Utility Model Content

[0012] This utility model relates to an apparatus for dehydrogenating n-chain alkanes into olefins, used in the production of straight-chain alkylbenzenes, characterized in that the apparatus comprises:

[0013] The deoxygenation unit (110) is connected to the triglyceride feed line (105);

[0014] C9 to C14 pipeline (115) and C14+ pipeline (120), wherein C9 to C14 pipeline (115) and C14+ pipeline (120) are connected to deoxygenation unit (110);

[0015] The first adsorbent bed contains a first adsorbent comprising alkali metal cations or alkaline earth metal cation exchange X-zeolite, and is connected to the first pipeline (130).

[0016] Purification pipeline (145) is connected to the first adsorbent bed;

[0017] A dehydrogenation unit (150) is connected to a purification line (145);

[0018] The dehydrogenation pipeline (155) is connected to the dehydrogenation unit (150).

[0019] In a preferred embodiment of this utility model, the device further includes:

[0020] Selective hydrogenation unit (160), which is connected to dehydrogenation line (155), and

[0021] A monoolefin pipeline (170) is connected to a selective hydrogenation unit (160).

[0022] In a preferred embodiment of this utility model, the device further includes:

[0023] An alkylation unit (175) connected to a monoolefin pipeline (170); and

[0024] The alkylation effluent line (185) is connected to the alkylation unit (175).

[0025] In a preferred embodiment of this utility model, the device further includes:

[0026] Benzene separation unit (190), which is connected to the alkylation effluent line (185); and

[0027] Linear alkylbenzene product pipeline (205); and

[0028] Benzene recirculation feed line (195);

[0029] The linear alkylbenzene product line (205) and the benzene recycling line (195) are connected to the benzene separation unit (190).

[0030] In a preferred embodiment of this utility model, the device further includes:

[0031] A linear selective cracking unit (125) is connected to a C14+ pipeline (120);

[0032] The first pipeline (130) is connected to the linear selective cracking unit (125); and

[0033] Second pipeline (135);

[0034] The first pipeline (130) and the second pipeline (135) are connected to the linear selective cracking unit (125).

[0035] In a preferred embodiment of this utility model, the device further includes:

[0036] An optional second adsorbent bed contains a second adsorbent comprising 5A zeolite.

[0037] In a preferred embodiment of this utility model, the device further includes:

[0038] An optional third adsorbent bed contains a third adsorbent comprising 13X zeolite, 5A zeolite, alumina zeolite, or a combination thereof.

[0039] In a preferred embodiment of this utility model, the device further includes:

[0040] The adsorbent bed is regenerated at a predetermined time to remove at least a portion of oxygen-containing compounds or aromatic compounds, or both, adsorbed onto the adsorbent. Detailed Implementation

[0041] This invention relates to a method for dehydrogenating n-alkanes into olefins. The alkanes are derived from renewable feedstocks, including natural oils such as vegetable oils, animal fats, nut oils and / or seed oils, as well as triglyceride-containing oils. The purification method for renewable bio-alkanes streams involves passing the stream through one or more adsorbent beds containing adsorbent.

[0042] Natural oils are not based on kerosene or other fossil fuels. Natural oils include those derived from plant or algal materials or animal fats, nut and / or seed oils, and oils containing triglycerides, and are often referred to as renewable oils. Natural oils typically contain triglycerides, free fatty acids, or combinations thereof. Natural oils include, but are not limited to, peanut oil (Arachis oil), babassu oil, coconut oil, cottonseed oil, grapeseed oil, maize oil, mustard oil, palm kernel oil, palm oil, palm oil extract (liquid fraction obtained from palm oil fractionation), palm stearin (high melting point fraction obtained from palm oil fractionation), rapeseed oil, low erucic acid rapeseed oil, safflower oil, safflower oil, and high oleic acid safflower oil. oil); high oleic acid safflower oil, sesame oil, bene oil, till oil, tillie oil, soybean oil, sunflower seed oil, and high oleic acid sunflower seed oil.

[0043] The feed stream derived from natural oils contains n-alkanes, isoalkanes, alkenes, oxygenated compounds, and up to 10% by weight of aromatic compounds.

[0044] Contaminants in the feed stream may include oxygenated compounds and / or aromatic compounds and / or fatty acids and fatty acid esters. Alkali metal cation or alkaline earth metal cation exchange X-zeolite can be used to remove at least a portion of oxygenated compounds, aromatic compounds, and fatty acids and fatty acid esters from alkane streams derived from natural oils. Suitable adsorbents for removing oxygenated compounds and aromatic compounds include, but are not limited to, alkali metal cation or alkaline earth metal cation exchange X-zeolite.

[0045] After removing contaminants, the treated stream contains no more than 6,000 ppm of aromatic compounds and no more than 100 ppm of oxygenated compounds.

[0046] Optionally, a second adsorbent bed may be included to further reduce the content of oxygenated compounds, aromatic compounds, and fatty acids and fatty acid esters in the treated stream. The second adsorbent includes, but is not limited to, 5A zeolite.

[0047] The first adsorbent bed and / or the second adsorbent bed can be regenerated at a predetermined time to remove at least a portion of oxygen-containing compounds or aromatic compounds, or both, adsorbed onto the first adsorbent and / or the second adsorbent.

[0048] There may be one or more first adsorbent beds and one or more second adsorbent beds.

[0049] Alkane streams from renewable feedstocks containing vegetable oils and animal fats may also contain other contaminants, such as sulfur compounds, nitrogen compounds, phosphorus compounds, or combinations thereof. These contaminants can be removed by passing the treated stream through a bed of third adsorbents containing a third adsorbent. The third adsorbent may include, but is not limited to, 13X zeolite, 5A zeolite, alumina-zeolite, or combinations thereof.

[0050] After the feed stream derived from natural oil has passed through a first adsorbent bed and optionally a second and / or a third adsorbent bed, the treated stream is dehydrogenated to convert at least a portion of the alkanes in the treated stream into olefins. The dehydrogenated stream contains monoolefins, dienes, and aromatic compounds.

[0051] The contaminant removal method can be incorporated into a method for preparing alkylbenzenes from natural oils. This method includes deoxygenating the natural oil to form alkanes. The alkanes are separated (by fractionation or distillation, etc.) into a C9-C14 stream containing C9-C14 alkanes and a C14+ stream containing C14+ alkanes. The C14+ stream is fed to a separate linear selective cracking unit to crack the C14+ alkanes; the cracked alkanes are fractionated into a first stream containing C9-C14 n-alkanes and slightly branched alkanes and a second stream containing isoalkanes. Contaminants, including but not limited to oxygenated compounds and / or aromatic compounds and / or fatty acids and fatty acid esters, and / or sulfur compounds, and / or nitrogen compounds, and / or phosphorus compounds, or combinations thereof, are removed from the C9-C14 stream and the first stream. The purified stream is dehydrogenated to form olefins, dienes, and aromatic compounds. The diene is selectively hydrogenated to form another olefin, and the aromatic compounds are separated and removed, resulting in an aromatic compound stream containing the aromatic compounds and a monoolefin stream containing the monoolefin. Benzene is alkylated with an olefin, and the alkylation effluent contains alkylbenzene and benzene. The alkylbenzene is then separated.

[0052] To limit catalyst deactivation, the feed is treated to remove sulfur contaminants prior to hydrodeoxygenation. Otherwise, sulfur accumulates on the catalyst and leads to deactivation. High-temperature hydrogenation treatment has shown some recovery of lost activity. The degree of hydrodeoxygenation can affect the selectivity for each n-alkanes in the 9 to 14 carbon range. Extensive hydrodeoxygenation can cause the hydrodeoxygenated composition to be heavily biased towards n-dodecane and n-decane, and undecane and n-tridecane. Less extensive hydrodeoxygenation can cause the hydrodeoxygenated composition to be biased towards n-undecane and n-tridecane, and unfavorable to n-dodecane and n-decane.

[0053] The hydrodeoxygenation reactor temperature is kept low, below 343°C (650°F) for typical biorenewable feedstocks and below 304°C (580°F) for feedstocks with high free fatty acid (FFA) concentrations, to avoid polymerization of olefins present in the FFA. Typically, a hydrodeoxygenation reactor pressure of 700 kPa (100 psig) to 21 MPa (3000 psig) is suitable.

[0054] The degree of linearity of alkylbenzene products depends primarily on the degree of linearity of the alkanes used to alkylate the benzene. A common rule of thumb among those skilled in the art is that the degree of linearity of the alkane feed decreases by 5%–7% by mass after dehydrogenation and alkylation. Therefore, an alkane with 97% linearity (or alternatively 3% by mass of isoalkanes) will produce an alkylbenzene product with approximately 90%–92% linearity. This sets a requirement for a alkane linearity 5%–7% higher than the specification of the alkylbenzene product. Typically, the degree of linearity of the alkane product is measured using standard test methods available from ASTM, such as UOP 621, UOP 411, or UOP 732, which are incorporated herein by reference in their entirety. Linear alkylbenzenes can be analyzed using ASTM standard test method D4337, which is also incorporated herein by reference in its entirety.

[0055] The accompanying drawings illustrate an exemplary system 100 for producing alkylbenzene products from a specific triglyceride feedstock.

[0056] In the illustrated embodiment, a selected triglyceride feed 105 is delivered to a deoxygenation unit 110, which also receives a hydrogen feed (not shown). In the deoxygenation unit 110, the fatty acids in the selected triglyceride feed 105 are deoxygenated and converted into n-chain alkanes. Triglycerides are structurally formed from three typically distinct fatty acid molecules linked together by glycerol bridges. A glycerol molecule includes three hydroxyl groups (HO--) and each fatty acid molecule has a carboxyl group (COOH). In triglycerides, the hydroxyl groups of glycerol bond with the carboxyl groups of the fatty acids to form ester bonds. Therefore, during deoxygenation, the fatty acids are released from the triglyceride structure and converted into n-chain alkanes. Glycerol is converted into propane, and the oxygen in the hydroxyl and carboxyl groups is converted into water, carbon dioxide, or carbon monoxide. The deoxygenation reactions of the fatty acids and triglycerides are shown separately as follows:

[0057]

[0058] During the deoxygenation reaction, the resulting alkane chain R n The length of the chain will vary depending on the exact reaction pathway. It should be understood that deoxygenation includes at least one of hydrodeoxygenation, decarboxylation, and decarbonylation reactions, or any combination thereof. For example, if carbon dioxide is formed, the chain will have one less carbon than the fatty acid source. If water is formed, the chain will match the length of the fatty acid source.

[0059] The operating conditions of the deoxidation unit include pressures ranging from 250 psig to 800 psig (1724 kPa to 5516 kPa) and temperatures ranging from 274°C to 371°C (525°F to 700°F) in one embodiment, from 274°C to 338°C (525°F to 640°F) in another embodiment, and from 274°C to 310°C (525°F to 590°F) in yet another embodiment. Catalysts may include those containing one or more of Ni, Mo, Co, and P (such as Ni-Mo, Ni-Mo-P, Ni-Co-Mo, or Co-Mo) on alumina, silica, titanium dioxide, zirconium oxide, or mixtures thereof. Suitable hydrogen to hydrocarbon molar ratios include 1500 to 10,000, 4000 to 9000, and 5000 to 8000 standard cubic feet per barrel (scf / B). Suitable space velocities include 0.2 hr. -1 -3.0hr -1 LHSV. Select conditions to minimize alkane cracking or isomerization.

[0060] The deoxygenation product containing n-alkanes, water, carbon dioxide, carbon monoxide, and propane is fractionated into C9 to C14 stream 115 and C14+ stream 120. Separation can be carried out in a multi-stage fractionation unit, distillation system, or similar known equipment. In any case, the separator removes water, carbon dioxide, carbon monoxide, and propane from the deoxygenation product. Alternatively, a naphtha stream (not shown) containing alkanes with carbon chain lengths of C5 to C9 can be formed.

[0061] C14+ feedstream 120 is fed to a linear selective cracking unit 125, where it is selectively cracked to form a first feedstream 130 containing C9 to C14 n-chain alkanes or lightly branched alkanes and a second feedstream 135 containing iso-alkanes. The linear selective cracking is carried out in a separate unit, rather than in the bottom bed of the first-stage hydrocracking reactor, because sulfur and nitrogen contaminants from the first stage can poison the metal-based hydrocracking catalyst. C14+ alkanes are selectively cracked before C9 to C14 alkanes due to their higher uptake energy.

[0062] By selecting specific metal catalysts, including noble metals such as ruthenium and platinum and nickel, it is possible to produce much higher yields of positive-chain alkanes with 9 to 14 carbons than previous methods. Suitable catalysts include, but are not limited to, Ru / ZrO2, Pt-Al2O3, Ni-alumina, or NiOx / clay. Using these catalysts, the C14+ feed stream is able to produce straight-chain cracking products without significant amounts of branched isomers.

[0063] Among the preferred catalysts, the Ru catalyst exhibits significantly higher activity and single-pass nC9 to nC14 yields than other catalysts. Under optimized reaction conditions, it also produces very small amounts of methane and isomerization products. It has been found to be the optimal catalyst for this type of chemical conversion. Pt-Al2O3 catalysts can produce even lower methane yields and slightly lower yields of straight-chain products than Ru-based catalysts.

[0064] The C9 to C14 feed stream 115 from the deoxidation unit 110 and the first feed stream 130 from the linear selective cracking unit 125 are fed to the purification unit 140, as described herein. The purification unit 140 removes contaminants from the C9 to C14 alkanes in the C9 to C14 feed stream 115 and the first feed stream 130. Contaminants include, but are not limited to, oxygenated compounds and / or aromatic compounds and / or fatty acids and fatty acid esters, and / or sulfur compounds, and / or nitrogen compounds, and / or phosphorus compounds, or combinations thereof.

[0065] The purified feed stream 145 is fed to the dehydrogenation unit 150, where hydrogen is removed to produce a dehydrogenated feed stream 155 containing mono-olefins, dienes, and aromatic compounds. In the dehydrogenation unit 150, alkanes are dehydrogenated to mono-olefins having the same number of carbon atoms as the alkanes. Typically, dehydrogenation is carried out by known catalytic methods, such as the commercially popular Pacol process. Dienes (i.e., dienes) and aromatic compounds are also produced as undesirable results of the dehydrogenation reaction, as shown in the following reaction equation:

[0066] Formation of monoolefins: C x H 2x+2 → C x H 2x + H2

[0067] Diene formation: C x H 2x → C x H 2x-2 + H2

[0068] Formation of aromatic compounds: C x H 2x-2 → C x H 2x-6 + 2H2

[0069] The operating conditions of the dehydrogenation unit 150 include space velocities of 5 LHSV to 50 LHSV and 20 LHSV to 32 LHSV; pressures of 34 kPa (g) to 345 kPa (g) (5 psig to 50 psig) and 103 kPa (g) to 172 kPa (g) (15 psig to 25 psig); temperatures of 400 °C to 500 °C and 440 °C to 490 °C; and hydrogen to hydrocarbon molar ratios of 1 to 12 and 3 to 7. An example of a suitable catalyst is a Pt / alumina catalyst, wherein platinum is degraded by a depressant metal. Another suitable catalyst is described in U.S. Patent 6,177,381, the entire contents of which are incorporated herein by reference. The dehydrogenation unit 150 can be operated in a dry environment or with water injection up to 2000 ppm by mass. Hydrogen can be recycled upstream of the dehydrogenation unit.

[0070] The dehydrogenation stream 155 is fed to a selective hydrogenation unit 160, such as a DeFine reactor, where at least a portion of the diene is hydrogenated to form additional monoolefins. As a result, the monoolefin stream 170 has an increased monoolefin concentration compared to the dehydrogenation stream 155. Aromatic compounds are separated and removed as aromatic compound stream 165. If desired, a light fraction stream 167 containing any light components (such as butane, propane, ethane, and methane) produced during upstream processing by cracking or other reactions can also be removed.

[0071] A monoolefin feed stream 170, containing a monoolefin, is fed together with a benzene feed stream 180 to an alkylation unit 175. Benzene is alkylated with the monoolefin to form an alkylbenzene. The alkylation unit 175 contains a catalyst supporting the alkylation of benzene with a monoolefin, such as a solid acid catalyst. Fluorinated silica-alumina, hydrogen fluoride (HF), aluminum chloride (AlCl3), zeolites, and ionic liquid catalysts are examples of commercially available catalysts for the alkylation of benzene with straight-chain monoolefins and can be used in the alkylation unit 175. As a result of the alkylation, an alkylbenzene, commonly referred to as a straight-chain alkylbenzene (LAB), is formed according to the following reaction:

[0072] C6H6 + C x H 2x → C6H5C x H 2x+1

[0073] Suitable operating conditions for alkylation unit 175 include space velocities of 1 LHSV to 10 LHSV, pressures for maintaining liquid-phase operation such as 2068 kPa (g) to 4137 kPa (g) (300 psig to 600 psig), temperatures in the range of 80°C to 180°C and 120°C to 170°C, and molar ratios of benzene to olefins of 3 to 40 and 8 to 35.

[0074] Excess benzene is supplied to alkylation unit 175 to achieve the desired high degree of alkylation. Therefore, the alkylation effluent 185 exiting alkylation unit 175 contains alkylbenzene and unreacted benzene. Additionally, alkylation effluent 185 may also include some unreacted alkanes. Alkylation effluent 185 is passed into benzene separation unit 190, such as a fractionating column, for separating unreacted benzene and alkanes from alkylation effluent 185. Unreacted benzene exits benzene separation unit 190 as benzene recycle stream 195, which can be fed back into alkylation unit 175 to maintain the desired benzene / olefin ratio (e.g., 1-50) to reduce the required volume of fresh benzene. The fresh benzene requirement (i.e., net benzene) is determined by the net olefins entering the alkylation unit. Alkane stream 200 can also be separated and recycled to dehydrogenation unit 150.

[0075] As a result of the post-alkylation separation process, linear alkylbenzene product 205 is separated. It should be noted that such a separation method is not necessary in all embodiments for separating linear alkylbenzene product 205.

[0076] Linear alkylbenzene product 205 is a linear alkylbenzene product comprising: having the formula C6H5C n H 2n+1 The alkylbenzene, wherein n is 9 to 14. In some embodiments, at least 80% by mass, or at least 90% by mass, of the alkylbenzene has a straight-chain alkyl group.

[0077] Linear alkylbenzenes can be sulfonated to provide linear alkylbenzene sulfonate products comprising: having the formula C n H 2n+ Alkylbenzene sulfonate compounds of 1C6H4SO3H, wherein n is 10 to 14, or wherein n is 11 to 13.

[0078] The term "tower" refers to one or more distillation columns used to separate one or more components with different volatility. Unless otherwise specified, each column includes a condenser at the top of the column for condensing a portion of the overhead feed and refluxing it back to the top of the column, and a reboiler at the bottom of the column for vaporizing a portion of the bottom feed and returning it to the bottom of the column. The feed to the column may be preheated. Top pressure is the pressure of the vapor at the top of the column at the vapor outlet. Bottom temperature is the liquid temperature at the bottom outlet of the column. Unless otherwise specified, top and bottom lines refer to the net lines from the bottom of the column to the column from any reflux or reboiler extract. Stripping columns may omit the reboiler at the bottom of the column and instead provide the heating requirements and separation power for liquefied inert media such as steam.

[0079] As used herein, the terms "component-rich stream" or "component stream" refer to a stream exiting a container with a higher component concentration than the feed into the container. As used herein, the term "component-lean stream" refers to a lean stream exiting a container with a lower component concentration than the feed into the container.

[0080] Example

[0081] Example 1

[0082] The coconut oil feed is deoxygenated to form alkanes, dehydrogenated to form monoolefins, and benzene is alkylated with monoolefins to form alkylbenzene products. These alkylbenzene products have a modern carbon content of 62% by mass (96% by mass) as determined by ASTM D6866, a bromine value of 1 g Br / g sample as determined by UOP Standard Test Method 304, and a linearity of 92% by mass, compared to a theoretical modern carbon content of 66.4% by mass.

[0083] Example 2

[0084] Oil was deoxygenated using a catalyst at a pressure of 480 psig H, with a bio-oil ratio of 7200 scf / B and an LHSV of 1 hr'. During operation, the deoxygenation reaction temperature was gradually increased from 315 °C (600 °F) to 34.9 °C (660 °F), then to 377 °C (710 °F) and 404 °C (760 °F) to monitor the response of linearity in the final product to reaction temperature. Results were obtained in... Figure 2 The figure shown is a graph of the concentration (in mass %) of C10-C13 n-chain alkanes versus the reaction temperature. Figure 2 It is clearly shown that the concentration of straight-chain alkanes decreases as the deoxygenation reaction temperature increases. Maintaining the temperature below 404°C (760°F) yields more than 92% by mass of straight-chain alkanes.

[0085] Note: Examples 1 and 2 were previously included in U.S. Patent 9,079,814 as Examples 3 and 4.

[0086] Specific implementation plan

[0087] While the following description is presented in conjunction with specific embodiments, it should be understood that the description is intended to illustrate, and not limit, the scope of the foregoing description and the appended claims.

[0088] A first embodiment of the present invention is a method for dehydrogenating n-alkanes to olefins, the method comprising passing a feed stream derived from a natural oil comprising C9 to C14 n-alkanes, isoalkanes, olefins, oxygen-containing compounds, and up to 10% by weight of aromatic compounds through a first adsorbent bed containing a first adsorbent comprising an alkali metal cation or an alkaline earth metal cation exchange X-zeolite, wherein the adsorbent removes at least a portion of the oxygen-containing compounds and aromatic compounds from the alkane feed stream by adsorption to form a treated feed stream; and dehydrogenating the treated feed stream to convert at least a portion of the treated feed stream into olefins and provide a dehydrogenated feed stream comprising monoolefins, dienes, and aromatic compounds. An embodiment of the present invention, which is one, any, or all of the embodiments preceding the first embodiment of this paragraph, further includes regenerating the adsorbent bed at a predetermined time to remove at least a portion of the oxygen-containing compounds or aromatic compounds, or both, adsorbed onto the adsorbent. One embodiment of the present invention, which is one, any, or all of the embodiments described in the preceding embodiments to the first embodiment of this paragraph, further includes: passing the treated stream through a second adsorbent bed containing a second adsorbent comprising 5A zeolite to remove additional oxygen-containing compounds and aromatic compounds, thereby forming a second treated stream. Another embodiment of the present invention, which is one, any, or all of the embodiments described in the preceding embodiments to the first embodiment of this paragraph, further includes regenerating the second adsorbent bed at a predetermined time to remove at least a portion of the oxygen-containing compounds or aromatic compounds, or both, adsorbed onto the second adsorbent. One embodiment of the invention is any one or all of the embodiments described in the preceding embodiments to the first embodiment of this paragraph, wherein the feed stream is formed by deoxygenating natural oil to form an alkane stream containing C9 to C28 alkanes; the alkane stream is subjected to linear selective cracking in a linear selective cracking unit in the presence of a linear selective cracking catalyst, under linear selective cracking conditions, to form a first feed stream containing C9 to C14 n-alkanes or slightly branched alkanes and a second feed stream containing isoalkanes. Another embodiment of the invention is any one or all of the embodiments described in the preceding embodiments to the first embodiment of this paragraph, further comprising removing contaminants from the treated feed stream in a third adsorbent bed containing a third adsorbent to form a purified feed stream prior to dehydrogenating the treated feed stream, wherein the contaminants comprise sulfur compounds, or nitrogen compounds, or phosphorus compounds, or combinations thereof, wherein the third adsorbent comprises 13X zeolite, 5A zeolite, alumina-zeolite, or combinations thereof.One embodiment of the invention is any one or all of the embodiments described in the preceding embodiments to the first embodiment of this paragraph, further comprising selectively hydrogenating the diene in the dehydrogenation stream to form an additional monoolefin, and separating and removing the aromatic compound from the monoolefin to form an aromatic compound stream containing the aromatic compound and a monoolefin stream containing the monoolefin, alkylating benzene with the monoolefin under alkylation conditions to provide an alkylated effluent containing alkylbenzene and benzene; separating the alkylbenzene to provide the alkylbenzene product derived from the natural oil. Another embodiment of the invention is any one or all of the embodiments described in the preceding embodiments to the first embodiment of this paragraph, wherein the treated stream contains no more than 6000 ppm of the aromatic compound and no more than 100 ppm of the oxygen-containing compound.

[0089] A second embodiment of the present invention is a method for dehydrogenating n-alkanes to olefins, the method comprising passing a feed stream containing n-alkanes, isoalkanes, olefins, up to 10% by weight of aromatic compounds and oxygen-containing compounds through an adsorbent bed containing an adsorbent comprising alkali metal cation exchange X-zeolite, wherein the adsorbent removes at least a portion of the oxygen-containing compounds and the aromatic compounds from the alkane feed stream by adsorption to form a treated feed stream; removing contaminants from the treated feed stream in a third adsorbent bed containing a third adsorbent to form a purified feed stream, wherein the contaminants comprise sulfur compounds, or nitrogen compounds, or phosphorus compounds, or combinations thereof, wherein the adsorbent comprises 13X zeolite, 5A zeolite, alumina-zeolite, or combinations thereof; dehydrogenating the purified feed stream to convert at least a portion of the purified feed stream into olefins and provide a dehydrogenated feed stream containing monoolefins, dienes, and aromatic compounds; and regenerating the adsorbent bed for a predetermined time to remove at least a portion of the oxygen-containing compounds or aromatic compounds, or both, adsorbed onto the adsorbent. One embodiment of the present invention, which is one, any, or all of the embodiments described in the preceding to the second embodiments of this paragraph, further includes: passing the treated stream through a second adsorbent bed containing a second adsorbent comprising 5A zeolite to remove additional oxygen-containing compounds and aromatic compounds before removing the contaminants in the third adsorbent bed, thereby forming a second treated stream. Another embodiment of the present invention, which is one, any, or all of the embodiments described in the preceding to the second embodiments of this paragraph, further includes regenerating the second adsorbent bed at a predetermined time to remove at least a portion of the oxygen-containing compounds or aromatic compounds, or both, adsorbed onto the second adsorbent. One embodiment of the present invention is one, any one, or all of the embodiments of the preceding embodiments to the second embodiments of this paragraph, wherein the feed stream is formed by deoxygenating natural oil to form an alkane stream containing C9 to C28 alkanes; the alkane stream is subjected to linear selective cracking in a linear selective cracking unit in the presence of a linear selective cracking catalyst, under linear selective cracking conditions, to form a first feed stream containing C9 to C14 n-alkanes or slightly branched alkanes and a second feed stream containing isoalkanes. One embodiment of the invention is one, any, or all of the embodiments described in the preceding to the second embodiments of this paragraph, further comprising selectively hydrogenating the diene in the dehydrogenation stream to form an additional monoolefin, separating and removing the aromatic compound from the monoolefin to form an aromatic compound stream containing the aromatic compound and a monoolefin stream containing the monoolefin, alkylating benzene with the monoolefin under alkylation conditions to provide an alkylated effluent containing alkylbenzene and benzene; separating the alkylbenzene to provide the alkylbenzene product derived from the natural oil.One embodiment of the present invention is one, any one, or all of the embodiments described in the preceding embodiments to the second embodiments of this paragraph, wherein the treated stream contains no more than 6000 ppm of the aromatic compound and no more than 100 ppm of the oxygen-containing compound.

[0090] A third embodiment of the present invention is a method for dehydrogenating n-alkanes to olefins, the method comprising: deoxygenating a natural oil to form an alkane feed stream containing C9 to C28 alkanes; subjecting the alkane feed stream to linear selective cracking in a linear selective cracking unit in the presence of a linear selective cracking catalyst, under linear selective cracking conditions, to form a first feed stream containing C9 to C14 n-alkanes or slightly branched alkanes and a second feed stream containing isoalkanes; passing the first feed stream containing n-alkanes, isoalkanes, olefins, oxygen-containing compounds, and up to 10% by weight of aromatic compounds through a first adsorbent bed containing a first adsorbent comprising an alkali metal cation or an alkaline earth metal cation exchange X-zeolite, wherein the adsorbent removes at least a portion of the oxygen-containing compounds and the aromatic compounds from the first feed stream by adsorption to form a treated feed stream; and, prior to dehydrogenating the treated feed stream, subjecting the third adsorbent bed to a third adsorbent bed. The process involves removing contaminants from the treated stream in a bed, the third adsorbent bed comprising a third adsorbent to form a purified stream, wherein the contaminants comprise sulfur compounds, or nitrogen compounds, or phosphorus compounds, or combinations thereof, wherein the third adsorbent comprises 13X zeolite, 5A zeolite, alumina-zeolite, or combinations thereof; dehydrogenating the purified stream to convert at least a portion of the purified stream into olefins and providing a dehydrogenated stream comprising monoolefins, dienes, and aromatic compounds; selectively hydrogenating the dienes in the dehydrogenated stream to form additional monoolefins; separating and removing the aromatic compounds from the monoolefins to form an aromatic compound stream comprising the aromatic compounds and a monoolefin stream comprising the monoolefins; alkylating benzene with the monoolefins under alkylation conditions to provide an alkylated effluent comprising alkylbenzenes and benzene; and separating the alkylbenzenes to provide the alkylbenzene product derived from the natural oil. One embodiment of the present invention, which is one, any one, or all of the embodiments described in the preceding to the third embodiments of this paragraph, further includes: regenerating the first adsorbent bed for a predetermined time to remove at least a portion of the oxygen-containing compounds or aromatic compounds, or both, adsorbed onto the first adsorbent. Another embodiment of the present invention, which is one, any one, or all of the embodiments described in the preceding to the third embodiments of this paragraph, further includes: passing the treated stream through a second adsorbent bed containing a second adsorbent comprising 5A zeolite to remove additional oxygen-containing compounds and aromatic compounds, thereby forming a second treated stream. A third embodiment of the present invention, which is one, any one, or all of the embodiments described in the preceding to the third embodiments of this paragraph, further includes: regenerating the second adsorbent bed for a predetermined time to remove at least a portion of the oxygen-containing compounds or aromatic compounds, or both, adsorbed onto the second adsorbent.One embodiment of the present invention is one, any one, or all of the embodiments described in the preceding embodiments to the third embodiment of this paragraph, wherein the treated stream contains no more than 6000 ppm of the aromatic compound and no more than 100 ppm of the oxygen-containing compound.

[0091] Although no further detailed description has been provided, it is believed that those skilled in the art will be able to fully utilize the invention by using the foregoing description and will be able to readily identify the essential features of the invention without departing from its spirit and scope, making various changes and modifications to adapt it to various uses and situations. Therefore, the foregoing preferred embodiments should be understood as illustrative only and not as limiting the remainder of this disclosure in any way, and are intended to cover various modifications and equivalent arrangements included within the scope of the appended claims.

[0092] In the foregoing, all temperatures are expressed in degrees Celsius, and all portions and percentages are by weight unless otherwise specified.

Claims

1. An apparatus for dehydrogenating n-chain alkanes into olefins, used in the production of straight-chain alkylbenzenes, characterized in that, The device includes: The deoxygenation unit (110) is connected to the triglyceride feed line (105); C9 to C14 pipeline (115) and C14+ pipeline (120), wherein C9 to C14 pipeline (115) and C14+ pipeline (120) are connected to deoxygenation unit (110); The first adsorbent bed contains a first adsorbent comprising alkali metal cations or alkaline earth metal cation exchange X-zeolite, and is connected to the first pipeline (130). Purification pipeline (145) is connected to the first adsorbent bed; A dehydrogenation unit (150) is connected to a purification line (145); The dehydrogenation pipeline (155) is connected to the dehydrogenation unit (150).

2. The apparatus according to claim 1, characterized in that, The device further includes: Selective hydrogenation unit (160), which is connected to dehydrogenation line (155), and A monoolefin pipeline (170) is connected to a selective hydrogenation unit (160).

3. The apparatus according to claim 1 or 2, characterized in that, The device further includes: An alkylation unit (175) connected to a monoolefin pipeline (170); and The alkylation effluent line (185) is connected to the alkylation unit (175).

4. The apparatus according to any one of the preceding claims, characterized in that, The device further includes: Benzene separation unit (190), which is connected to the alkylation effluent line (185); and Linear alkylbenzene product pipeline (205); and Benzene recirculation feed line (195); The linear alkylbenzene product line (205) and the benzene recycling line (195) are connected to the benzene separation unit (190).

5. The apparatus according to any one of the preceding claims, characterized in that, The device further includes: A linear selective cracking unit (125) is connected to a C14+ pipeline (120); The first pipeline (130) is connected to the linear selective cracking unit (125); and Second pipeline (135); The first pipeline (130) and the second pipeline (135) are connected to the linear selective cracking unit (125).

6. The apparatus according to claim 1, characterized in that, The device further includes: An optional second adsorbent bed contains a second adsorbent comprising 5A zeolite.

7. The apparatus according to claim 1, characterized in that, The device further includes: An optional third adsorbent bed contains a third adsorbent comprising 13X zeolite, 5A zeolite, alumina zeolite, or a combination thereof.

8. The apparatus according to any one of claims 1-3, characterized in that, The device further includes: The adsorbent bed is regenerated at a predetermined time to remove at least a portion of oxygen-containing compounds or aromatic compounds, or both, adsorbed onto the adsorbent.

Images