Straight-run light naphtha processing method

Abstract

The invention discloses a straight-run light naphtha conversion method. The method comprises the following steps: (a) mixing straight-run light naphtha and a material flow rich in olefin to obtain a reactant flow; the content of C5-C6 isoparaffin in the light naphtha is 20 to 40 weight percent; and (b) mixing the reactant flow in the step (a) with hydrogen, and contacting with a light naphtha conversion catalyst for reaction to obtain a converted light naphtha product. By adopting the method disclosed by the invention, the proportion of the normal hydrocarbon in the straight-run light naphtha can be increased.

Description

Technical Field

[0001] This invention relates to the field of petrochemical technology, specifically to a method for processing straight-run light naphtha (mainly referring to hydrocarbons rich in C5 and C6 hydrocarbons). Background Technology

[0002] Straight-run light naphtha is a light component obtained from crude oil through atmospheric distillation. Its content varies considerably depending on the origin of the crude oil, typically ranging from 1 wt% to 10 wt%. Straight-run light naphtha is mainly composed of C5 and C6 saturated hydrocarbons, with isomeric hydrocarbons comprising 20 wt% to 40 wt%. It is commonly used as a feedstock for ethylene production via steam cracking.

[0003] The yields of ethylene and trienes vary significantly when hydrocarbons with different structures are used as feedstocks for steam cracking ethylene. For example, isoalkanes such as isobutane, isopentane, and isohexane yield ethylene at 12.2%, 21.9%, and 24.2%, respectively, and triene yields at 37.9%, 43.9%, and 57.2%, respectively; while n-alkanes such as n-butane, n-pentane, and n-hexane yield ethylene at 40.8%, 41.8%, and 39.3%, respectively, and triene yields at 61.1%, 62.8%, and 61.6%, respectively. This indicates that the yields of ethylene and trienes from isoalkanes are significantly lower than those from n-alkanes. Increasing the proportion of n-alkanes in straight-run light naphtha is key to improving the yields of ethylene and trienes. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method for processing straight-run light naphtha, which can effectively increase the content of n-hydrocarbons in straight-run light naphtha, thereby significantly increasing the olefin yield of steam cracking ethylene production units.

[0005] The first aspect of this invention provides a method for converting straight-run light naphtha, comprising:

[0006] (a) Straight-run light naphtha and olefin-rich streams are mixed to obtain a reaction stream;

[0007] (b) The reaction stream from step (a) is mixed with hydrogen and then reacted with a light naphtha conversion catalyst to obtain the converted light naphtha product; the light naphtha conversion catalyst comprises modified ZSM-5 molecular sieve and macroporous alumina supported on Group VIB and Group VIII metals; wherein the mesoporous pore volume of the modified ZSM-5 molecular sieve accounts for 50% to 80% of the total pore volume, preferably 60% to 70%.

[0008] Further, in step (a), the initial boiling point of the straight-run light naphtha is 15℃~40℃, and the final boiling point is 60℃~90℃. The content of C5-C6 isoalkanes in the straight-run light naphtha is 20wt%~40wt%, preferably 30wt%~40wt%, based on a total weight of 100wt% of the straight-run light naphtha.

[0009] Further, in step (a), the olefin-rich stream is selected from pure olefins or olefin-rich light naphtha. The pure olefin is selected from at least one of butene, pentene, and hexene; the present invention does not impose any particular limitation on the proportion of butene, pentene, and hexene in the olefin-rich stream. The olefin-rich light naphtha is one or more of catalytic cracking light naphtha and delayed coking light naphtha; the present invention does not impose any particular limitation on the mixing ratio of the added catalytic cracking light naphtha and delayed coking light naphtha. Preferably, the mass content of C4-C6 olefins in the catalytic cracking light naphtha is 40wt% to 60wt%, and the mass content of C4-C6 olefins in the delayed coking light naphtha is 30wt% to 50wt%.

[0010] Further, in step (a), the olefin content in the reaction stream is 0.03 to 1.5 wt%, preferably 0.08 to 1.0 wt%, for example, but not limited to, 0.08 wt%, 0.1 wt%, 0.15 wt%, 0.2 wt%, 0.25 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1.0 wt%, and any range between any two values.

[0011] Further, in step (b), the reaction conditions are: a reaction temperature of 300–450°C, a reaction pressure of 2.0–80 MPa, and a liquid hourly space velocity of 0.1–5.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 100:1 to 2000:1.

[0012] Further, in step (b), based on the weight of the light naphtha conversion catalyst, the content of modified ZSM-5 molecular sieve is 35wt%–80wt%, the content of macroporous alumina is 15wt%–50wt%, and the total content of Group VIB and Group VIII metals (calculated as oxides) is 0.5wt%–8.0wt%. Preferably, based on the weight of the light naphtha conversion catalyst, the content of modified ZSM-5 molecular sieve is 50wt%–75wt%, the content of macroporous alumina is 20wt%–30wt%, and the total content of Group VIB and Group VIII metals (calculated as oxides) is 1.0wt%–5.0wt%. Further, the Group VIB metal is preferably molybdenum and / or tungsten, and the Group VIII metal is preferably cobalt and / or nickel. Further, in the macroporous alumina loaded with Group VIB and Group VIII metals, the mass ratio of Group VIB metals (calculated as oxides) to Group VIII metals (calculated as oxides) is 2.0–6.0.

[0013] Furthermore, the pore volume of the macroporous alumina is 0.8–1.5 cm³.3 / g, specific surface area of ​​200-400m² 2 / g.

[0014] Furthermore, the total content C of Group VIB and Group VIII metals on the surface of the conversion catalyst is... ms The total content of Group VIB and Group VIII metals in the catalyst bulk phase, C mt The molar ratio is 0.60–0.90. The total amount of Group VIB and Group VIII metals on the catalyst surface, C ms This refers to the total molar amount, in atomic terms, of Group VIB and Group VIII metals per gram of catalyst surface. The total amount of Group VIB and Group VIII metals in the catalyst bulk phase, C. mt It refers to the total molar amount of Group VIB and Group VIII metals per gram of catalyst bulk phase, expressed in atomic quantities.

[0015] Furthermore, the preparation method of the hydrogenation conversion catalyst includes the following steps:

[0016] (1) Pore expansion treatment of ZSM-5 molecular sieve;

[0017] (2) Remove non-framework aluminum from step (1) to obtain modified ZSM-5 molecular sieve;

[0018] (3) Macroporous alumina was impregnated with an impregnation solution containing Group VIB and Group VIII metals and then calcined to obtain macroporous alumina loaded with Group VIB and Group VIII metals.

[0019] (4) The modified ZSM-5 molecular sieve and macroporous alumina loaded with Group VIB and Group VIII metals were mixed, shaped, and calcined to obtain a hydroconversion catalyst.

[0020] Further, in step (1), the ZSM-5 molecular sieve can be a commercially available product or a microporous hydrogen-form ZSM-5 molecular sieve prepared according to existing technology. The properties of the ZSM-5 molecular sieve are as follows: SiO2 / Al2O3 molar ratio 30-100, specific surface area 300-450 m² / g. 2 / g, pore volume 0.15~0.20cm³ 3 / g.

[0021] Further, in step (1), the pore-expanding treatment can be one or more of acid treatment, alkali treatment, and hydrothermal treatment, preferably hydrothermal treatment. The temperature of the hydrothermal treatment is 400-700℃, preferably 500-600℃, the time is 0.5-5h, preferably 1-2h, and the pressure is 0.05-0.5MPa, preferably 0.1-0.3MPa.

[0022] Further, in step (2), the method for removing non-skeletal aluminum can be a buffer solution method. The buffer solution used is one or more of oxalic acid-ammonium oxalate solution and acetic acid-ammonium acetate solution. The pH value of the buffer solution is 4.5-6.5, preferably 5.0-6.0. The molar concentration of the organic acid in the buffer solution is 0.1-1.0 mol / L. The liquid-solid volume ratio of the buffer solution to the molecular sieve obtained in step (1) is 3:1-10:1.

[0023] Further, in step (2), the specific process for removing non-skeletal aluminum is as follows: the molecular sieve obtained in step (1) is mixed with a buffer solution and stirred, the treatment temperature is 40-80℃, the treatment time is 0.5-3h, and then solid-liquid separation (e.g., vacuum filtration) is performed; and the above operation is repeated 2-4 times.

[0024] Furthermore, the impregnation in step (3) is performed using a pressure impregnation method.

[0025] Furthermore, the pressure impregnation includes: mixing macroporous alumina with an impregnation solution containing Group VIB and Group VIII metals, and impregnating in a closed atmosphere under nitrogen.

[0026] Furthermore, the impregnation conditions include: a pressure of 0.5–3.0 MPa, a temperature of 60–80 °C, and an impregnation time of 1–4 h.

[0027] Further, the impregnation is preferably carried out under stirring at a stirring rate of 100–300 rpm. Further, after impregnation, stirring and heating are stopped, and the mixture is allowed to stand for 2–4 hours until cooled to room temperature. The resulting material is first subjected to conventional filtration and drying, and then calcined to obtain macroporous alumina loaded with Group VIB and Group VIII metals. The drying temperature is 100°C–150°C, and the drying time is 2–4 hours; the calcination temperature is 400°C–600°C, and the calcination time is 3–5 hours.

[0028] Furthermore, in step (3), the pore volume of the macroporous alumina is 0.8–1.5 cm³. 3 / g, specific surface area of ​​200-400m² 2 / g.

[0029] Further, in step (3), the impregnation solution containing Group VIB and Group VIII metals contains one or more of tungsten or molybdenum salts as the source of the Group VIB metal, and one or more of nickel or cobalt salts as the source of the Group VIII metal. Further, in the impregnation solution containing Group VIB and Group VIII metals, the mass content of the Group VIB metal (calculated as oxide) is 3.0–30.0 g / 100 mL, and the mass content of the Group VIII metal (calculated as oxide) is 1.0–10.0 g / 100 mL.

[0030] Further, in step (3), the pH value of the impregnation solution containing Group VIB and Group VIII metals is 8.0 to 10.0. Further, there are no particular limitations on the pH adjuster used; conventional pH adjusters in the art can be used.

[0031] Furthermore, in step (4), the mass ratio of macroporous alumina loaded with Group VIB and Group VIII metals to modified ZSM-5 molecular sieve is 0.2 to 1.0.

[0032] Further, in step (4), the molding can be carried out using conventional methods in the art, such as extrusion molding. Conventional molding aids can be added during the molding process, such as at least one of extrusion aids and pectinic acids; the extrusion aid can be guar gum powder, and the pectinic acid can be at least one of citric acid and nitric acid, preferably citric acid and nitric acid. The amount of molding aid added accounts for 1.0% to 5.0% of the mass of the hydroconversion catalyst.

[0033] Further, in step (4), after molding, the catalyst is dried and calcined to obtain the catalyst. The drying temperature is 100℃~150℃, and the drying time is 2~4h; the calcination temperature is 400℃~600℃, and the calcination time is 3~5h.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] 1. Compared to long-chain alkanes, the dehydrogenation process is more difficult to carry out during the conversion of light hydrocarbons. As the controlling step of the overall reaction, increasing the number of metal active centers can improve the dehydrogenation activity of the catalyst. In this invention, a small amount of olefin-rich stream is introduced. The olefins can rapidly react with the acidic centers of the catalyst to generate carbocations. After the generated carbocations complete the reaction, they continue to propagate, allowing the reaction to continue, thus acting as an initiator.

[0036] 2. The proportion of isoalkanes in straight-run naphtha is usually less than 50%, resulting in a low probability of contact between isoalkanes and the catalyst. The catalyst used in this invention employs ZSM-5 molecular sieves with a higher mesopore content, which promotes the contact and reaction between isoalkanes and acid centers in the feedstock, thereby improving the conversion selectivity of isoalkanes.

[0037] 3. In the catalyst of this invention, the hydrogenation metal is mainly supported on macroporous alumina, resulting in low hydrogenation activity within the molecular sieve channels, reducing carbocation saturation, and promoting the conversion of light naphtha. After the n-olefins or small molecule olefins obtained from the conversion of light hydrocarbons diffuse out of the molecular sieve channels, they rapidly contact the hydrogenation centers on the alumina, undergoing a saturation reaction, preventing carbon deposition, and improving catalyst stability. Detailed Implementation

[0038] The following examples and comparative examples further illustrate the role and effect of the technical solution of the present invention, but the following examples do not constitute a limitation on the scope of protection of the present invention.

[0039] In this invention, the total amount C of Group VIB and Group VIII metals on the catalyst surface is... ms The elemental composition and state of the catalyst surface (3 nm–10 nm) were determined by X-ray photoelectron spectroscopy (XPS) using a Thermofisher Multilab 2000 electron spectrometer. The excitation source was Mg Kα, and the cathode voltage and current were 13 kV and 20 mA, respectively. The electron binding energy was calibrated using C1s (284.6 eV). The data obtained directly from XPS are mass percentages, C ms The values ​​are converted to mol / g.

[0040] In this invention, the total content of Group VIB and Group VIII metals in the bulk phase of the catalyst is C. mt The results were obtained by X-ray fluorescence spectroscopy (XRF) analysis using a ZSX100e X-ray fluorescence spectrometer. The spectral line was Kα, the crystal was LiF1, the target material was Rh, the detector was SC scintillation, the timing was 20 s, and the optical atmosphere was vacuum. The data obtained directly from XRF were mass percentages, C. mt The values ​​are converted to mol / g. The total amount of Group VIB and Group VIII metals in the bulk catalyst refers to the total amount of Group VIB and Group VIII metals in the entire catalyst.

[0041] In this invention, the specific surface area, pore volume, and pore distribution were measured using the following method: an ASAP 2420 cryogenic liquid nitrogen physical adsorption instrument manufactured by Microlithics, Inc. was used, with a pretreatment temperature of 300°C and a pretreatment time of 4 hours.

[0042] In this invention, the amount of carbon deposited on the catalyst is measured by an infrared sulfur and carbon analyzer. A high-frequency infrared carbon and sulfur analyzer of EMIA-820V from HORIBA Corporation of Japan is used. The high-frequency induction heating furnace has an output power of 2300W and a frequency of 20MHz. The sample heating temperature is 1800℃. The carbon content of the catalyst is calculated based on the peak area of ​​the vibrational spectrum of CO2 generated by the combustion of carbon deposits.

[0043] In this invention, unless otherwise specified, all percentages (%) in the embodiments and comparative examples refer to mass fractions.

[0044] In this invention, the ZSM-5 molecular sieve involved in the embodiments and comparative examples is a commercially available product with a pore volume of 0.18 cm³. 3 / g, specific surface area is 191cm³ 2 / g, the silicon-to-aluminum molar ratio of SiO2:Al2O3 is 55. The macroporous alumina is a commercially available product with a pore volume of 1.1 cm³. 3 / g, specific surface area is 350cm² 2 / g.

[0045] In this invention, the conversion rate of light naphtha isohydrocarbons, the selectivity of isohydrocarbon conversion, and the proportion of n-alkanes in the products are calculated as follows:

[0046] Isomer hydrocarbon conversion rate = (mass of isomer C5 and C6 hydrocarbons in feedstock - mass of isomer C5 and C6 hydrocarbons in product) / (mass of isomer C5 and C6 hydrocarbons in feedstock) × 100%;

[0047] Isomer hydrocarbon conversion selectivity = (mass of isomer C5 and C6 hydrocarbons in feedstock - mass of isomer C5 and C6 hydrocarbons in product) / (mass of C5 and C6 hydrocarbons in feedstock - mass of C5 and C6 hydrocarbons in product) × 100%;

[0048] The proportion of n-alkane = mass of n-alkane in the product / total mass of the product × 100%, where n-alkane includes ethane, propane, n-butane, n-pentane and n-hexane.

[0049] In this invention, the olefin-rich stream introduced in each example is a mixed olefin of butene, pentene, and hexene. The olefin content refers to the total content of butene, pentene, and hexene.

[0050] In this invention, in each example, the nickel source used is nickel nitrate, and the tungsten source is ammonium metatungstate.

[0051] Example 1

[0052] Preparation of modified ZSM-5 molecular sieve (denoted as Z-1): Commercially available ZSM-5 molecular sieve was placed in a hydrothermal treatment furnace and treated at 450℃ and 0.1MPa steam pressure for 2 hours to obtain modified ZSM-5 molecular sieve Z-1, with a mesopore volume of 0.09 cm³. 3 / g, total pore volume is 0.17cm³ 3 / g, mesoporous pore volume accounts for 52% of the total pore volume.

[0053] 100g of macroporous alumina was impregnated for 2h with 200mL of an aqueous solution containing 2.0g / 100mL of nickel (calculated as oxide, nickel source was nickel nitrate), 10.0g / 100mL of tungsten (calculated as oxide, tungsten source was ammonium metatungstate), and pH 9.0. The impregnation pressure was 1.0MPa and the impregnation temperature was 60℃. After impregnation, the alumina was cooled to room temperature, filtered, dried at 120℃ for 3h, and calcined at 450℃ for 3h to obtain macroporous alumina loaded with nickel oxide and tungsten oxide, denoted as A-NW-1.

[0054] Take 100g of Z-1 molecular sieve and 30g of A-NW-1 material, mix them, add 85g of pectinic acid (concentration 1wt%) and 1g of extrusion aid guar gum powder, then crush, extrude into strips, dry at 120℃ for 3h, and calcine at 500℃ for 4h to obtain the catalyst, denoted as CAT-1, whose properties are shown in Table 1.

[0055] Example 2

[0056] Preparation of modified ZSM-5 molecular sieve (denoted as Z-2): Commercially available ZSM-5 molecular sieve was placed in a hydrothermal treatment furnace and treated at 500℃ and 0.1MPa steam pressure for 2 hours to obtain modified ZSM-5 molecular sieve Z-2, with a mesopore volume of 0.11 cm³. 3 / g, total pore volume is 0.17cm³ 3 / g, mesoporous pore volume accounts for 65% of the total pore volume.

[0057] The macroporous alumina loaded with nickel oxide and tungsten oxide in this example is the same as the macroporous alumina loaded with nickel oxide and tungsten oxide in Example 1 (denoted as A-NW-1);

[0058] Take 100g of Z-2 molecular sieve and 30g of A-NW-1 material, mix them, add 85g of pectinic acid (concentration 1wt%) and 1g of extrusion aid guar gum powder, then crush, extrude into strips, dry at 120℃ for 3h, and calcine at 500℃ for 4h to obtain the catalyst, denoted as CAT-2, whose properties are shown in Table 1.

[0059] Example 3

[0060] The modified ZSM-5 molecular sieve in this embodiment is the same as the modified ZSM-5 molecular sieve in Example 1 (denoted as Z-1).

[0061] Take 100g of macroporous alumina and immerse it in 200mL of an aqueous solution with a nickel content of 1.0g / 100mL, a tungsten content of 5.0g / 100mL, and a pH of 9.0 for 2h. The immersion pressure is 0.5MPa and the immersion temperature is 70℃. After immersion, cool to room temperature, filter, dry at 120℃ for 3h, and calcine at 450℃ for 3h to obtain macroporous alumina loaded with nickel oxide and tungsten oxide, denoted as A-NW-2.

[0062] Take 100g of Z-1 molecular sieve and 30g of A-NW-2 material, mix them, add 85g of pectinic acid (concentration 1wt%) and 1g of extrusion aid guar gum powder, then crush, extrude into strips, dry at 120℃ for 3h, and calcine at 500℃ for 4h to obtain the catalyst, denoted as CAT-3, whose properties are shown in Table 1.

[0063] Example 4

[0064] The modified ZSM-5 molecular sieve in this embodiment is the same as the modified ZSM-5 molecular sieve in Example 2 (denoted as Z-2).

[0065] Take 100g of macroporous alumina and immerse it in 200mL of an aqueous solution with a nickel content of 2.0g / 100mL, a tungsten content of 10.0g / 100mL, and a pH of 10.0 for 2h. The immersion pressure is 2.0MPa and the immersion temperature is 80℃. After immersion, cool to room temperature, filter, dry at 120℃ for 3h, and calcine at 450℃ for 3h to obtain macroporous alumina loaded with nickel oxide and tungsten oxide, denoted as A-NW-3.

[0066] Take 80g of Z-2 molecular sieve and 50g of A-NW-3 material, mix them, add 90g of pectinic acid (concentration 1wt%) and 1g of extrusion aid guar gum powder, then crush, extrude into strips, dry at 120℃ for 3h, and calcine at 500℃ for 4h to obtain the catalyst, denoted as CAT-4, whose properties are shown in Table 1.

[0067] Example 5

[0068] Preparation of modified ZSM-5 molecular sieve (denoted as Z-3): Commercially available ZSM-5 molecular sieve was placed in a hydrothermal treatment furnace and treated at 600℃ and 0.1MPa steam pressure for 2 hours to obtain modified ZSM-5 molecular sieve Z-3, with a mesopore volume of 0.14 cm³. 3 / g, total pore volume is 0.18cm³ 3 / g, mesoporous pore volume accounts for 78% of the total pore volume.

[0069] The macroporous alumina loaded with nickel oxide and tungsten oxide in this example is the same as the macroporous alumina loaded with nickel oxide and tungsten oxide in Example 1 (denoted as A-NW-1);

[0070] Take 100g of Z-3 molecular sieve and 30g of A-NW-1 material, mix them, add 85g of pectinic acid (concentration 1wt%) and 1g of extrusion aid guar gum powder, then crush, extrude into strips, dry at 120℃ for 3h, and calcine at 500℃ for 4h to obtain the catalyst, denoted as CAT-5, whose properties are shown in Table 1.

[0071] Example 6

[0072] The modified ZSM-5 molecular sieve in this embodiment is the same as the modified ZSM-5 molecular sieve in Example 2 (denoted as Z-2).

[0073] Take 100g of macroporous alumina and immerse it in 200mL of an aqueous solution with a nickel content of 1.0g / 100mL, a tungsten content of 5.0g / 100mL (based on oxides), and a pH of 8.0 for 2h. The immersion pressure is 2.0MPa and the immersion temperature is 80℃. After immersion, cool to room temperature, filter, dry at 120℃ for 3h, and calcine at 450℃ for 3h to obtain macroporous alumina loaded with nickel oxide and tungsten oxide, denoted as A-NW-4.

[0074] Take 50g of Z-2 molecular sieve and 50g of A-NW-4 material, mix them, add 75g of pectinic acid (concentration 1wt%) and 1g of extrusion aid guar gum powder, then crush, extrude into strips, dry at 120℃ for 3h, and calcine at 500℃ for 4h to obtain the catalyst, denoted as CAT-6, whose properties are shown in Table 1.

[0075] Comparative Example 1

[0076] 100g of modified ZSM-5 molecular sieve (denoted as Z-1) and 45g of macroporous alumina were mixed, and 85g of pectinic acid (1wt%) and 1g of extrusion aid guar gum powder were added. The mixture was then rolled, extruded into strips, dried at 120℃ for 3 hours, and calcined at 500℃ for 4 hours to obtain DA-NW-1. 100g of DA-NW-1 was impregnated in 200mL of an aqueous solution containing 1.5g / 100mL of nickel and 8.0g / 100mL of tungsten (based on oxides) for 2 hours. After filtration, drying at 120℃ for 3 hours, and calcining at 500℃ for 4 hours, a catalyst was obtained, denoted as DCAT-1. Its properties are shown in Table 1.

[0077] Comparative Example 2

[0078] The macroporous alumina loaded with nickel oxide and tungsten oxide in this example is the same as the macroporous alumina loaded with nickel oxide and tungsten oxide in Example 1 (denoted as A-NW-1).

[0079] Take 100g of commercially available ZSM-5 molecular sieve and 30g of A-NW-1 material, mix them together, add 85g of pectinic acid (concentration 1wt%) and 1g of extrusion aid guar gum powder, then crush, extrude into strips, dry at 120℃ for 3h, and calcine at 500℃ for 4h to obtain the catalyst, denoted as DCAT-2, whose properties are shown in Table 1.

[0080] Comparative Example 3

[0081] The modified ZSM-5 molecular sieve in this example is the same as the modified ZSM-5 molecular sieve in Example 1 (denoted as Z-1).

[0082] Take 100g of macroporous alumina and immerse it in 200mL of an aqueous solution with a nickel content of 8.0g / 100mL, a tungsten content of 40.0g / 100mL (based on oxides), and a pH of 9.0 for 2h. The immersion pressure is 1.0MPa and the immersion temperature is 60℃. After immersion, cool to room temperature, filter, dry at 120℃ for 3h, and calcine at 450℃ for 3h to obtain macroporous alumina loaded with nickel oxide and tungsten oxide, denoted as A-NW-D3.

[0083] Take 100g of Z-1 molecular sieve and 30g of A-NW-D3 material, mix them, add 85g of pectinic acid (concentration 1wt%) and 1g of extrusion aid guar gum powder, then crush, extrude into strips, dry at 120℃ for 3h, and calcine at 500℃ for 4h to obtain the catalyst, denoted as DCAT-3, whose properties are shown in Table 1.

[0084] Comparative Example 4

[0085] The modified ZSM-5 molecular sieve in this example is the same as the modified ZSM-5 molecular sieve in Example 1 (denoted as Z-1).

[0086] Take 100g of macroporous alumina and immerse it in 200mL of an aqueous solution (pH 5.4) containing 2.0g / 100mL of nickel and 10.0g / 100mL of tungsten (calculated as oxides) for 2h. After filtration, drying at 120℃ for 3h and calcining at 450℃ for 3h, macroporous alumina loaded with nickel oxide and tungsten oxide is obtained, denoted as A-NW-D4.

[0087] Take 100g of Z-1 molecular sieve and 30g of A-NW-D4 material, mix them, add 85g of pectinic acid (concentration 1wt%) and 1g of extrusion aid guar gum powder, then crush, extrude into strips, dry at 120℃ for 3h, and calcine at 500℃ for 4h to obtain the catalyst, denoted as DCAT-4, whose properties are shown in Table 1.

[0088] Comparative Example 5

[0089] The modified ZSM-5 molecular sieve in this example is the same as the modified ZSM-5 molecular sieve in Example 1 (denoted as Z-1).

[0090] Take 100g of small-pore alumina (pore volume 0.48cm³). 3 / g, specific surface area is 251cm³ 2 The nickel oxide and tungsten oxide were impregnated in 200 mL of an aqueous solution with a nickel content of 2.0 g / 100 mL, a tungsten content of 10.0 g / 100 mL (based on oxides), and a pH of 9.0 for 2 h. The impregnation pressure was 1.0 MPa and the impregnation temperature was 60 °C. After impregnation, the mixture was cooled to room temperature, filtered, dried at 120 °C for 3 h, and calcined at 450 °C for 3 h to obtain a porous alumina loaded with nickel oxide and tungsten oxide, denoted as A-NW-D5.

[0091] Take 100g of Z-1 molecular sieve and 30g of A-NW-D5 material, mix them, add 85g of pectinic acid (concentration 1wt%) and 1g of extrusion aid guar gum powder, then crush, extrude into strips, dry at 120℃ for 3h, and calcine at 500℃ for 4h to obtain the catalyst, denoted as DCAT-5, whose properties are shown in Table 1.

[0092] Table 1. Composition and properties of catalysts in the examples and comparative examples.

[0093]

[0094]

[0095] Note: The alumina content of DCAT-5 is calculated based on microporous alumina, while the content of the other catalysts is calculated based on macroporous alumina.

[0096] Example 7

[0097] 3.0 mL of catalyst CAT-1 was placed in a fixed-bed reactor. Straight-run light naphtha mixed with olefin-rich components (olefin content 0.08 wt%) was introduced into the reactor at a flow rate of 10 mL / h to contact the catalyst CAT-1 for reaction. The reaction conditions were as follows: reaction pressure 4.0 MPa, hydrogen-to-oil volume ratio 400:1, and reaction temperature 400℃. The properties of the feedstock are shown in Table 2. After 160 h of operation, the isomeric hydrocarbon conversion rate, isomeric hydrocarbon conversion selectivity, product n-hydrocarbon content, and catalyst carbon deposition are shown in Table 3.

[0098] Example 8

[0099] 3.0 mL of catalyst CAT-2 was placed in a fixed-bed reactor. Straight-run light naphtha mixed with olefin-rich components (olefin content 1.0 wt%) was introduced into the reactor at a flow rate of 10 mL / h to contact the catalyst CAT-2 for reaction. The reaction conditions were as follows: reaction pressure 4.0 MPa, hydrogen-to-oil volume ratio 400:1, and reaction temperature 400℃. The properties of the feedstock are shown in Table 2. After 160 h of operation, the isomeric hydrocarbon conversion rate, isomeric hydrocarbon conversion selectivity, product n-hydrocarbon content, and catalyst carbon deposition are shown in Table 3.

[0100] Example 9

[0101] 3.0 mL of catalyst CAT-3 was placed in a fixed-bed reactor. Straight-run light naphtha mixed with olefin-rich components (olefin content 0.1 wt%) was introduced into the reactor at a flow rate of 10 mL / h to contact the catalyst CAT-3 for reaction. The reaction conditions were as follows: reaction pressure 4.0 MPa, hydrogen-to-oil volume ratio 400:1, and reaction temperature 400℃. The properties of the feedstock are shown in Table 2. After 160 h of operation, the isomeric hydrocarbon conversion rate, isomeric hydrocarbon conversion selectivity, product n-hydrocarbon content, and catalyst carbon deposition are shown in Table 3.

[0102] Example 10

[0103] 3.0 mL of catalyst CAT-4 was placed in a fixed-bed reactor. Straight-run light naphtha mixed with olefin-rich components (olefin content 0.2 wt%) was introduced into the reactor at a flow rate of 10 mL / h to contact the catalyst CAT-4 for reaction. The reaction conditions were as follows: reaction pressure 4.0 MPa, hydrogen-to-oil volume ratio 400:1, and reaction temperature 400℃. The properties of the feedstock are shown in Table 2. After 160 h of operation, the isomeric hydrocarbon conversion rate, isomeric hydrocarbon conversion selectivity, product n-hydrocarbon content, and catalyst carbon deposition are shown in Table 3.

[0104] Example 11

[0105] 3.0 mL of catalyst CAT-5 was placed in a fixed-bed reactor. Straight-run light naphtha (olefin content 0.5 wt%) mixed with olefin-rich components was introduced into the reactor at a flow rate of 10 mL / h to contact the catalyst CAT-5 for reaction. The reaction conditions were as follows: reaction pressure 4.0 MPa, hydrogen-to-oil volume ratio 400:1, and reaction temperature 400℃. The properties of the feedstock are shown in Table 2. After 160 h of operation, the isomeric hydrocarbon conversion rate, isomeric hydrocarbon conversion selectivity, product n-hydrocarbon content, and catalyst carbon deposition are shown in Table 3.

[0106] Example 12

[0107] 3.0 mL of catalyst CAT-6 was placed in a fixed-bed reactor. Straight-run light naphtha mixed with olefin-rich components (olefin content 0.8 wt%) was introduced into the reactor at a flow rate of 10 mL / h to contact the catalyst CAT-6 for reaction. The reaction conditions were as follows: reaction pressure 4.0 MPa, hydrogen-to-oil volume ratio 400:1, and reaction temperature 400℃. The properties of the feedstock are shown in Table 2. After 160 h of operation, the isomeric hydrocarbon conversion rate, isomeric hydrocarbon conversion selectivity, product n-hydrocarbon content, and catalyst carbon deposition are shown in Table 3.

[0108] Comparative Example 6

[0109] 3.0 mL of catalyst CAT-1 was placed in a fixed-bed reactor. Straight-run light naphtha was introduced into the reactor at a flow rate of 10 mL / h to react with catalyst CAT-1. The reaction conditions were as follows: reaction pressure 4.0 MPa, hydrogen-to-oil volume ratio 400:1, and reaction temperature 400℃. The properties of the feedstock are shown in Table 2. After 160 h of operation, the isomeric hydrocarbon conversion rate, isomeric hydrocarbon conversion selectivity, n-hydrocarbon content in the product, and catalyst carbon deposition are shown in Table 4.

[0110] Comparative Example 7

[0111] 3.0 mL of catalyst CAT-1 was placed in a fixed-bed reactor. Straight-run light naphtha mixed with olefin-rich components (olefin content 2.0 wt%) was introduced into the reactor at a flow rate of 10 mL / h to contact the catalyst CAT-1 for reaction. The reaction conditions were as follows: reaction pressure 4.0 MPa, hydrogen-to-oil volume ratio 400:1, and reaction temperature 400℃. The properties of the feedstock are shown in Table 2. After 160 h of operation, the isomeric hydrocarbon conversion rate, isomeric hydrocarbon conversion selectivity, product n-hydrocarbon content, and catalyst carbon deposition are shown in Table 4.

[0112] Comparative Example 8

[0113] 3.0 mL of catalyst DCAT-1 was placed in a fixed-bed reactor. Straight-run light naphtha (olefin content 0.5 wt%) mixed with olefin-rich components was introduced into the reactor at a flow rate of 10 mL / h to contact the catalyst DCAT-1 for reaction. The reaction conditions were as follows: reaction pressure 4.0 MPa, hydrogen-to-oil volume ratio 400:1, and reaction temperature 400℃. The properties of the feedstock are shown in Table 2. After 160 h of operation, the isomeric hydrocarbon conversion rate, isomeric hydrocarbon conversion selectivity, product n-hydrocarbon content, and catalyst carbon deposition are shown in Table 4.

[0114] Comparative Example 9

[0115] 3.0 mL of catalyst DCAT-2 was placed in a fixed-bed reactor. Straight-run light naphtha (olefin content 0.5 wt%) mixed with olefin-rich components was introduced into the reactor at a flow rate of 10 mL / h to contact the catalyst DCAT-2 for reaction. The reaction conditions were as follows: reaction pressure 4.0 MPa, hydrogen-to-oil volume ratio 400:1, and reaction temperature 400℃. The properties of the feedstock are shown in Table 2. After 160 h of operation, the isomeric hydrocarbon conversion rate, isomeric hydrocarbon conversion selectivity, product n-hydrocarbon content, and catalyst carbon deposition are shown in Table 4.

[0116] Comparative Example 10

[0117] 3.0 mL of catalyst DCAT-3 was placed in a fixed-bed reactor. Straight-run light naphtha (olefin content 0.5 wt%) mixed with olefin-rich components was introduced into the reactor at a flow rate of 10 mL / h to contact the catalyst DCAT-3 for reaction. The reaction conditions were as follows: reaction pressure 4.0 MPa, hydrogen-to-oil volume ratio 400:1, and reaction temperature 400℃. The properties of the feedstock are shown in Table 2. After 160 h of operation, the isomeric hydrocarbon conversion rate, isomeric hydrocarbon conversion selectivity, product n-hydrocarbon content, and catalyst carbon deposition are shown in Table 4.

[0118] Comparative Example 11

[0119] 3.0 mL of catalyst DCAT-4 was placed in a fixed-bed reactor. Straight-run light naphtha (olefin content 0.5 wt%) mixed with olefin-rich components was introduced into the reactor at a flow rate of 10 mL / h to contact the catalyst DCAT-4 for reaction. The reaction conditions were as follows: reaction pressure 4.0 MPa, hydrogen-to-oil volume ratio 400:1, and reaction temperature 400℃. The properties of the feedstock are shown in Table 2. After 160 h of operation, the isomeric hydrocarbon conversion rate, isomeric hydrocarbon conversion selectivity, product n-hydrocarbon content, and catalyst carbon deposition are shown in Table 4.

[0120] Comparative Example 12

[0121] 3.0 mL of catalyst DCAT-5 was placed in a fixed-bed reactor. Straight-run light naphtha (olefin content 0.5 wt%) mixed with olefin-rich components was introduced into the reactor at a flow rate of 10 mL / h to contact the catalyst DCAT-5 for reaction. The reaction conditions were as follows: reaction pressure 4.0 MPa, hydrogen-to-oil volume ratio 400:1, and reaction temperature 400℃. The properties of the feedstock are shown in Table 2. After 160 h of operation, the isomeric hydrocarbon conversion rate, isomeric hydrocarbon conversion selectivity, product n-hydrocarbon content, and catalyst carbon deposition are shown in Table 4.

[0122] Table 2 Composition and properties of straight-run light naphtha

[0123] composition content <![CDATA[C5 - ]]> 4.2wt% <![CDATA[C5]]> 49.8wt% <![CDATA[i-C5 (i-C5 Isoparaffin)]]> 19.6wt% <![CDATA[n-C5 (n-Pentane)]]> 30.2wt% <![CDATA[C6]]> 41.3wt% <![CDATA[i-C6 (i-C6 Isoparaffin)]]> 14.5wt% <![CDATA[n-C6 (n-hexane)]]> 26.8wt% <![CDATA[C6 + ]]> 4.7wt% Initial boiling point, ℃ 15.3 Final boiling point, ℃ 75.2

[0124] Table 3 Evaluation results of the catalysts in the examples

[0125]

[0126] Table 4 Evaluation results of the comparative example catalysts

[0127]

[0128] The specific embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for converting straight-run light naphtha, comprising: (a) Straight-run light naphtha and olefin-rich streams are mixed to obtain a reaction stream; (b) The reaction stream from step (a) is mixed with hydrogen and then reacted with a light naphtha conversion catalyst to obtain the converted light naphtha product; the light naphtha conversion catalyst comprises modified ZSM-5 molecular sieve and macroporous alumina supported on Group VIB and Group VIII metals; wherein the mesoporous pore volume of the modified ZSM-5 molecular sieve accounts for 50% to 80% of the total pore volume, preferably 60% to 70%.

2. The method according to claim 1, characterized in that, The olefin-rich stream is selected from either pure olefin substances or olefin-rich light naphtha. Preferably, the pure olefin is selected from at least one of butene, pentene, and hexene; the olefin-rich light naphtha is one or more of catalytic cracking light naphtha and delayed coking light naphtha. Preferably, the mass content of C4-C6 olefins in the catalytic cracking light naphtha is 40wt% to 60wt%, and the mass content of C4-C6 olefins in the delayed coking light naphtha is 30wt% to 50wt%.

3. The method according to claim 1, characterized in that, The initial boiling point of the straight-run light naphtha is 15℃~40℃, and the final boiling point is 60℃~90℃. Preferably, the C5-C6 isoalkanes in the straight-run light naphtha are 20wt% to 40wt%, more preferably 30wt% to 40wt%.

4. The method according to claim 1, characterized in that, In step (a), the olefin content in the reaction stream is 0.03 to 1.5 wt%, preferably 0.08 to 1.0 wt%.

5. The method according to claim 1, characterized in that, In step (b), the reaction conditions are: a reaction temperature of 300–450 °C, a reaction pressure of 2.0–80 MPa, and a liquid hourly space velocity of 0.1–5.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 100:1 to 2000:

1.

6. The method according to claim 1, characterized in that, In step (b), the catalyst comprises modified ZSM-5 molecular sieve and macroporous alumina supported on Group VIB and Group VIII metals; Preferably, the Group VIB metals are molybdenum and / or tungsten, and the Group VIII metals are cobalt and / or nickel.

7. The method according to claim 6, characterized in that, In the catalyst, based on the weight of the catalyst, the content of modified ZSM-5 molecular sieve is 35wt% to 80wt%, the content of macroporous alumina is 15wt% to 50wt%, and the total content of Group VIB and Group VIII metals as oxides is 0.5wt% to 8.0wt%.

8. The method according to claim 6, characterized in that, In the catalyst, based on the weight of the catalyst, the content of modified ZSM-5 molecular sieve is 50wt% to 75wt%, the content of macroporous alumina is 20wt% to 30wt%, and the total content of Group VIB and Group VIII metals as oxides is 1.0wt% to 5.0wt%.

9. The method according to claim 6, characterized in that, The mesoporous pore volume of the modified ZSM-5 molecular sieve accounts for 50% to 80% of the total pore volume, preferably 60% to 70%. And / or, the pore volume of the macroporous alumina is 0.8–1.5 cm³. 3 / g, specific surface area of ​​200-400m² 2 / g.

10. The method according to claim 6, characterized in that, The total content C of Group VIB and Group VIII metals on the surface of the conversion catalyst ms The total content of Group VIB and Group VIII metals in the catalyst bulk phase, C mt The molar ratio is 0.60 to 0.90.

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