A hydrogenation catalyst and a method for preparing the same

Abstract

The application relates to a hydrogenation catalyst and a preparation method thereof, and belongs to the technical field of catalysts. The method comprises the following steps: 1) soaking sepiolite in deionized water, settling, and removing impurities to obtain substance a; 2) uniformly mixing the substance a with metatitanic acid, adding a pore-expanding agent, a binder and water, shaping, drying, and calcining to obtain a carrier b; 3) preparing a mixed solution of cobalt salt and nickel salt, adding molybdenum salt, a complexing agent and a solvent to obtain an impregnation liquid c, impregnating the carrier b in the impregnation liquid c, drying, and calcining to obtain a mixture d; and 4) preparing an impregnation liquid e by taking nickel salt, ammonium hydrogen phosphate and a solvent, impregnating the mixture d in the impregnation liquid e, drying, and calcining to obtain the hydrogenation catalyst. The active component of the prepared hydrogenation catalyst is distributed in multiple layers from the outside of the carrier to the inside of the carrier, the outermost layer of the core is nickel phosphide, the middle layer of the shell is active metal components of nickel oxide and molybdenum oxide, and the core is molybdenum oxide and cobalt oxide. The hydrogenation catalyst can realize oxidation state activation and has high low-temperature activity.

Description

Technical Field

[0001] A hydrogenation catalyst and its preparation method are disclosed, belonging to the field of catalyst technology. Background Technology

[0002] The production and efficient utilization of hydrogen energy is currently a key research focus and hot topic in universities and social research institutions. To meet the coming hydrogen energy era, the development of modular hydrogen production units and their supporting catalysts is urgently needed. For modular hydrocarbon steam reforming hydrogen production units, due to the highly integrated reactors and more demanding process conditions, the process conditions and activities of existing industrial catalysts cannot meet the requirements. Therefore, it is necessary to develop hydrogenation agents with high activity suitable for modular hydrogen production. Sulfur and chlorine in hydrocarbon hydrogen production feedstocks must be removed to prevent poisoning and catalyst conversion. Cobalt-molybdenum catalysts are commonly used to remove organic sulfur and organic chlorine from hydrogen production feedstocks, generating easily removable H2S and HCl, which will then undergo further fine desulfurization.

[0003] Currently, most commonly used hydrogenation catalysts consist of group VIB and / or group VIII metals, such as W, Mo, Co, and Ni. These existing catalysts require pre-sulfurization before use, transforming the catalyst components from an oxidized state to a sulfidized state for activation. The reason for continuing this method is that, in existing technologies, the activity and stability of sulfidized catalysts are significantly improved, making them more suitable for industrial production.

[0004] Conventional pre-sulfurization methods are divided into online in-reactor pre-sulfurization and external pre-sulfurization. In-reactor pre-sulfurization involves loading the oxidized catalyst into the reactor and simultaneously introducing hydrogen and a sulfiding agent or hydrogen at a certain temperature to pre-sulfurize the catalyst, converting the active metal components of the catalyst into the sulfided state. In-reactor pre-sulfurization can be further divided into dry pre-sulfurization and wet pre-sulfurization.

[0005] External pre-sulfurization technology can be divided into two main categories: one is external pre-sulfurization technology that uses elemental sulfur, organic polysulfides, inorganic sulfides, and hydrogen sulfide as sulfiding agents. The other is a technology that, after normal sulfidation, the catalyst undergoes passivation or other pretreatment to improve the stability and initial activity of the sulfidated catalyst, facilitating catalyst storage and transportation. Among these, the pre-sulfurization method using sulfur-containing compounds has a high degree of sulfidation due to the diverse types of sulfides, which are easily lost with the gas during the heating process in industrial units, resulting in a lower degree of sulfidation and affecting its conversion activity and service life. With internal pre-sulfurization, modular hydrogen production units lack a source of sulfur; with external pre-sulfurization, there are safety and environmental hazards due to the issue of sulfur release during unit startup.

[0006] Patent CN109722302A describes a combined cracking and desulfurization method and apparatus, as well as a combined process of catalytic cracking and adsorption desulfurization. It discloses the catalytic cracking catalyst and desulfurization catalyst used. This patent directly performs adsorption desulfurization on liquefied petroleum gas (LPG) and gasoline and / or diesel without separation, followed by LPG and gasoline and / or diesel separation, thereby reducing separation costs. Although this patent uses sepiolite as a support and incorporates nickel, cobalt, and molybdenum elements in the catalyst, it does not achieve catalyst activation in its oxidative state, nor does it address how to improve the catalyst's low-temperature activity.

[0007] Patent CN112473697B describes a core-shell spherical nickel-cobalt-tungsten multi-component sulfide catalyst. The patent first disperses cobalt, nickel nitrate, and glycerol in isopropanol and reacts them in a hydrothermal reactor at 160°C for several hours to obtain a nickel-cobalt-glycerol precursor. Subsequently, ammonium tungstate and thioacetamide are dissolved in ethanol and mixed with the previously obtained nickel-cobalt-glycerol precursor. After reacting in a hydrothermal reactor for several hours, the mixture is dried and calcined to obtain a core-shell spherical Co9S8-Ni3S2@WS2 catalyst. This catalyst can be used in solar cells, but its application is different, and the patent does not address how to activate the catalyst in its oxidative state.

[0008] Commonly used industrial catalysts require sulfidation and a temperature of 350°C to achieve high activity, which causes significant inconvenience in industrial production. Given the process limitations of modular hydrogen production units and the high-temperature activation drawbacks of existing industrial catalysts, there is an urgent need to develop a hydrogenation catalyst suitable for modular units that is activated in its oxidized state and exhibits high activity at low temperatures. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a hydrogenation catalyst and its preparation method. The prepared hydrogenation catalyst can achieve oxidation activation and has high activity at low temperature.

[0010] The technical solution adopted by the present invention to solve its technical problem is: a method for preparing the hydrogenation catalyst, characterized by comprising the following steps:

[0011] 1) Soak sepiolite in deionized water, allow it to settle, remove impurities, and obtain substance a;

[0012] 2) Mix substance a with metatitanic acid evenly, add pore expander, binder and water, and then shape, dry and calcin to obtain carrier b;

[0013] 3) Prepare a mixed solution of cobalt salt and nickel salt, and add molybdenum salt, complexing agent and solvent to obtain impregnation solution c. Place carrier b in impregnation solution c for impregnation, then dry and calcine to obtain mixture d;

[0014] 4) Prepare impregnation solution e by taking nickel salt, ammonium hydrogen phosphate salt and solvent, place mixture d in impregnation solution e for impregnation, then dry and calcine to obtain the final product.

[0015] The mass ratio of metatitanic acid in step 2) to sepiolite in step 1) is 1:3-1:8.

[0016] Step 3) The concentration of the impregnation solution c and the porosity of the carrier b satisfy the following relationship: C=C1 / C2, A=C×ґ / Ԑ

[0017] C1 is the mass concentration of cobalt ions in impregnation solution c;

[0018] C2 is the mass concentration of nickel ions in impregnation solution c;

[0019] ґ represents the catalyst tortuosity factor;

[0020] Ԑ represents the porosity of carrier b;

[0021] A represents the impact factor;

[0022] C represents the mass concentration ratio of cobalt and nickel ions;

[0023] The value range of C is 0.1-1; the value range of A is 0.1-5.9;

[0024] The value range of ґ is 2-7.7; the value range of Ԑ is 1.3-1.62.

[0025] Preferably, the value of C is in the range of 0.65-1; the value of A is in the range of 2.5-4.5; the value of ґ is in the range of 4.4-7.6; and the value of Ԑ is in the range of 1.3-1.4.

[0026] Step 3) involves preparing a mixed solution of cobalt and nickel salts, specifically by preparing a mixed solution of cobalt and nickel salts within the range of C. C is the mass concentration ratio of cobalt and nickel ions, and the value of C ranges from 0.1 to 1.

[0027] Step 3) The mass ratio of the molybdenum salt, cobalt salt and nickel salt is 1:0.67-1.2:1-1.2.

[0028] Step 3) The complexing agent is one or two of ammonia, citric acid, and phosphoric acid.

[0029] Step 3) The specific operation of roasting is as follows: heat up to 180-250℃ at a rate of 1-4℃ / min, roast at a constant temperature for 1-2 hours, and then heat up to 350-450℃ at a rate of 1-4℃ / min and roast at a constant temperature for 2-3 hours.

[0030] Preferably, the specific operation of the roasting in step 3) is as follows: the temperature is increased to 200-250℃ at a rate of 2-3℃ / min and roasted at a constant temperature for 1.5-2 hours, and then the temperature is increased to 450℃ at a rate of 2-3℃ / min and roasted at a constant temperature for 2.5 hours.

[0031] In step 4), the mass ratio of the nickel salt to the ammonium hydrogen phosphate salt is 0.4-2.0:1. Preferably, the mass ratio of the nickel salt to the ammonium hydrogen phosphate salt in step 4) is 0.5-1.9:1.

[0032] Step 4) The specific operation of the roasting is as follows: heat up to 180-200℃ at a rate of 1-4℃ / min, roast at a constant temperature for 1-2 hours, and then heat up to 400-500℃ at a rate of 1-4℃ / min and roast at a constant temperature for 2-3 hours.

[0033] Preferably, the specific operation of the roasting in step 4) is as follows: the temperature is increased to 180-200℃ at a rate of 2-3℃ / min, and roasted at a constant temperature for 2 hours, and then the temperature is increased to 450℃ at a rate of 1-4℃ / min and roasted at a constant temperature for 2.5 hours.

[0034] The hydrogenation catalyst prepared according to the preparation method has its active components distributed in multiple layers from the outside to the inside of the support. The outermost active component of the core is nickel phosphide, the active metal components of the middle shell are nickel oxide and molybdenum oxide, and the core is molybdenum oxide and cobalt oxide.

[0035] The catalyst contains 12.5-22% by mass of active components, which are calculated as nickel phosphide, cobalt oxide, molybdenum oxide and nickel oxide. The content of nickel phosphide accounts for 4-6% of the catalyst mass, the content of molybdenum oxide accounts for 6-10% of the catalyst mass, the content of cobalt oxide accounts for 1-3% of the catalyst mass, the content of nickel oxide accounts for 1.5-3% of the catalyst mass, and the remaining components of the catalyst are composite supports.

[0036] The outermost layer of the catalyst core has a thickness of 0.2-0.5 mm, the middle layer of the shell has a thickness of 0.2-0.8 mm, and the core layer has a thickness of 0.5-1.3 mm.

[0037] The catalyst is columnar in shape, with a clover-shaped or circular cross-section with a diameter of 2.0 mm to 3.5 mm. The sum of the thicknesses of the outermost core, the middle shell, and the core layer is less than or equal to the cross-sectional radius of the catalyst.

[0038] The present invention is described as follows:

[0039] The soaking time in step 1) is 30-240 minutes, preferably 45-100 minutes.

[0040] The mixing time in step 2) is 20-180 min, preferably 30-60 min.

[0041] The soaking in step 1), the immersion in step 3), and the immersion in step 4 are all carried out at room temperature.

[0042] The drying process in step 2) is carried out at a temperature of 90-110℃. The specific operation of the roasting process in step 2) is as follows: the temperature is increased to 180-200℃ at a rate of 2-3℃ / min and roasted at a constant temperature for 1-1.5h, and then the temperature is increased to 340-350℃ at a rate of 2-3℃ / min and roasted at a constant temperature for 4-4.5h.

[0043] Step 2) The adhesive is one or both of nitric acid and citric acid; Step 2) The pore-expanding agent is polyethylene glycol, starch, or sucrose. Preferably, Step 2) The pore-expanding agent is polyethylene glycol, which has both pore-expanding and lubricating effects.

[0044] Step 2) The adhesive is one or both of nitric acid and citric acid; Step 2) The pore-expanding agent is polyethylene glycol, starch, or sucrose. Preferably, Step 2) The pore-expanding agent is polyethylene glycol, which has both pore-expanding and lubricating effects.

[0045] The drying process in step 3) is carried out at a temperature of 80-110℃. The drying process in step 4) is carried out at a temperature of 80-110℃.

[0046] Step 3) The molybdenum salt is one of molybdenum nitrate, molybdenum acetate, and molybdenum oxalate; Step 3) The cobalt salt is one of cobalt nitrate, cobalt acetate, and cobalt oxalate; Step 3) The nickel salt is one of nickel nitrate, nickel acetate, and nickel oxalate. Step 3) The solvent is water.

[0047] Step 4) The nickel salt is one of nickel nitrate, nickel acetate, and nickel oxalate; Step 4) The ammonium hydrogen phosphate salt is diammonium hydrogen phosphate. Preferably, Step 4) The nickel salt is nickel nitrate. Step 4) The solvent is water.

[0048] The application of the hydrogenation catalyst of this invention is in the field of low-temperature activation of hydrogenation agents for hydrogen production feedstocks without sulfurization. Specifically, the hydrogenation catalyst of this invention can be used as a feedstock in reactions with light hydrocarbons at temperatures of 200-400°C and hydrocarbon gas space velocities of 800-4000 h⁻¹. －1 The system is activated without sulfurization under a pressure of 2.5-3.5 MPa, removing organic sulfur from the feedstock to generate hydrogen sulfide. Light hydrocarbons include natural gas, syngas, and refinery gas.

[0049] In the hydrogenation catalyst of this invention, the outermost active component, nickel phosphide, is prepared via step 4), while the middle shell and core are both prepared via step 3). However, the active components of the middle shell and core are different: the active metal components of the middle shell are nickel oxide and molybdenum oxide, and the core is molybdenum oxide and cobalt oxide. The applicant discovered in their research that when the prepared impregnation solution c satisfies the relationships C=C1 / C2 and A=C×₁ / ₂ (where C ranges from 0.1 to 1 and A ranges from 0.1 to 5.9), the carrier impregnated with an appropriate concentration of active component under these conditions can effectively form a multilayered distribution of active components.

[0050] The hydrogenation catalyst of this invention has different compositions and functions in its outermost core, middle shell, and core layers. The composition and impregnation order of each layer cannot be arbitrarily changed. The outermost core layer promotes the activation of the oxidized state and initiates the hydrogenation reaction. The sulfides produced in the reaction gradually diffuse into the catalyst interior, and are gradually reduced through the middle shell and core layers, sulfiding the oxidized metal. The active components in the middle shell layer ensure the low-temperature activity of the catalyst, while the active components in the core layer ensure the hydrogenation activity of the catalyst.

[0051] Step 2) The carrier b is a titanium dioxide-sepiolite composite carrier. Sepiolite is a magnesium-rich silicate clay mineral. Its theoretical chemical formula is Mg8[Si 12 O 30 Sepiolite (OH)₄·12H₂O contains 4 water molecules that are crystallization water and the rest are zeolite water. Sepiolite is a chain-like hydrous magnesium aluminum silicate or magnesium silicate mineral belonging to the S monoclinic or orthorhombic crystal system. It has a huge specific surface area, which can adsorb various reactants and active components of catalysts. Due to the presence of both alkaline and acidic centers in sepiolite, reactants are easily polarized at these centers into activated complexes, resulting in a synergistic catalytic effect with the catalyst. Sepiolite has a fibrous structure, which can form a large specific surface area and interparticle voids, resulting in strong adsorption and providing more active sites. However, sepiolite has poor mechanical strength and is not strong enough to be used alone as a catalyst support, requiring the addition of other supports. Titanium dioxide has a suitable acidity on its surface and a weak interaction with the active components, improving the dispersion of the active components and the reduction degree of the active phase. At the same time, there is a synergistic effect between it and the active components, acting as an electronic auxiliary agent. However, titanium dioxide has the disadvantages of small specific surface area and poor thermal stability. To overcome these shortcomings, sepiolite-titanium dioxide is made into a composite support, utilizing the high specific surface area and high thermal stability of sepiolite to overcome the defects of titanium dioxide itself, while maintaining the advantages of titanium dioxide in hydrodesulfurization reactions.

[0052] Compared with the prior art, the beneficial effects of the present invention are:

[0053] 1. The hydrogenation catalyst of this invention can achieve activation in the oxidized state and exhibit high activity at low temperatures. The active metal components of the catalyst prepared by this invention are distributed in multiple layers along the radial direction of the support. The outermost active component of the core is nickel phosphide, the active metal components of the middle shell are nickel oxide and molybdenum oxide, and the core is molybdenum oxide and cobalt oxide. This multi-layered structure provides initial catalyst activity to promote the hydrogenation reaction, while the generated sulfides gradually diffuse into the catalyst interior to oxidize the sulfide-oxidized metal, improving catalyst activity. This allows the hydrogenation catalyst in the modular hydrogen production unit to be activated in the oxidized state at low temperatures, achieving environmental protection and energy conservation.

[0054] In the titanium dioxide-sepiolite composite support, the acidic and basic centers of sepiolite transform adsorbed organic matter into activated complexes. Titanium dioxide enters the sepiolite fiber rod layer structure, stabilizing the catalyst structure, enhancing acidity, increasing active sites, and improving catalyst reactivity. The composite support facilitates the dispersion of active components, making them easier to reduce. The interaction between the active components and the support is weakened, making it easier for metal oxides to form active component sulfides in the presence of hydrogen sulfide.

[0055] 2. The hydrogenation catalyst of this invention produces no sulfur release during use and is environmentally friendly. In industrial applications, the hydrogenation catalyst prepared by this invention can achieve low-temperature activation of hydrogen production feedstock without sulfurization, producing no sulfur release and being environmentally friendly, thus demonstrating good economic benefits and application prospects. The hydrogenation catalyst of this invention can use light hydrocarbons such as natural gas, syngas, and refinery gas as feedstocks. In process applications, a reaction temperature of 200-400℃ and a hydrocarbon gas space velocity of 800-4000 h⁻¹ are used. －1 Under system pressure of 2.5-3.5 MPa, the catalyst can be directly activated in the oxidized state of the feed at 200℃, removing organic sulfur from the feed to generate hydrogen sulfide. Attached Figure Description

[0056] Figure 1 This is a schematic diagram of the structure of the catalyst obtained in Example 1.

[0057] Figure 2 This is a schematic diagram of the process for a small-scale hydrogenation evaluation device in performance testing.

[0058] Wherein: 101, outermost core layer; 102, middle shell layer; 103, core; D, catalyst cross-sectional diameter; x, thickness of the outermost layer; y, thickness of the middle shell layer; z, thickness of the core; 1, mass flow meter; 2, shut-off valve; 3, preheater; 4, reactor; 5, separator; 6, gasification chamber; 7, flow valve; 8, chromatograph; 9, pressure gauge. Detailed Implementation

[0059] The present invention will be further described below with reference to specific embodiments, wherein Embodiment 1 is the preferred embodiment. The comparative examples are designed to compare the effects of the embodiments.

[0060] Reference Figure 1 The hydrogenation catalyst has its active components distributed in multiple layers from the outside to the inside of the support. The outermost core layer 101 is composed of nickel phosphide, the middle shell layer 102 is composed of nickel oxide and molybdenum oxide, and the core 103 is composed of molybdenum oxide and cobalt oxide. The thickness x of the outermost core layer 101 is 0.2-0.5 mm, the thickness y of the middle shell layer 102 is 0.2-0.8 mm, and the thickness z of the core 103 is 0.5-1.3 mm. The catalyst is columnar with a clover-shaped or circular cross-sectional diameter D of 2.0 mm-3.5 mm. To reduce variation, the catalysts used in the examples and comparative examples are columnar with a circular cross-sectional diameter D of 3.5 mm.

[0061] Example 1

[0062] The preparation method of the hydrogenation catalyst in this embodiment includes the following steps:

[0063] 1) Take 64.3g of sepiolite and soak it in deionized water. After sedimentation and removal of impurities, substance a is obtained.

[0064] 2) Mix substance a with 26.3g metatitanic acid evenly, add 3g polyethylene glycol, 3g citric acid, 3g nitric acid and 57g water, shape, dry at 90℃, heat to 200℃ at a rate of 2℃ / min and calcine at a constant temperature for 1h, then heat to 350℃ at a rate of 2℃ / min and calcine at a constant temperature for 4.5h to obtain carrier b;

[0065] 3) Prepare a mixed aqueous solution of cobalt nitrate and nickel nitrate with a C value of 0.65, and add 8.4 g of molybdenum nitrate, 4.53 g of citric acid and 50 g of water to obtain impregnation solution c. Place the carrier b in impregnation solution c and impregnate for 1 hour, then dry at 90°C, then heat to 200°C at a rate of 2°C / min and calcine at a constant temperature for 1.5 h, then heat to 450°C at a rate of 2°C / min and calcine at a constant temperature for 2.5 h to obtain mixture d;

[0066] 4) Take 17.9g of nickel nitrate, 15.86g of ammonium hydrogen phosphate and water to prepare impregnation solution e. Place the mixture d in impregnation solution e and impregnate for 1 hour. Then dry at 90℃, then heat to 180℃ at a rate of 3℃ / min and calcine at a constant temperature for 2 hours. Then heat to 450℃ at a rate of 3℃ / min and calcine at a constant temperature for 2.5 hours to obtain the catalyst. The catalyst is labeled A.

[0067] Example 2

[0068] The preparation method of the hydrogenation catalyst in this embodiment includes the following steps:

[0069] 1) Take 53.8g of sepiolite and soak it in deionized water. After sedimentation and removal of impurities, substance a is obtained.

[0070] 2) Mix substance a with 22.0g metatitanic acid evenly, add 3g starch, 3g citric acid, 3g nitric acid and 53g water, shape, dry at 110℃, heat to 180℃ at a rate of 3℃ / min and calcine at a constant temperature for 1.5h, then heat to 340℃ at a rate of 3℃ / min and calcine at a constant temperature for 4.5h to obtain carrier b;

[0071] 3) Prepare a mixed aqueous solution of cobalt nitrate and nickel nitrate with a C value of 1, and add 15.7g of molybdenum nitrate, 8.46g of citric acid and 52g of water to obtain impregnation solution c. Place the carrier b in impregnation solution c and impregnate for 1.5 hours, then dry at 80℃, then heat to 250℃ at a rate of 3℃ / min and calcine at a constant temperature for 2 hours, and then heat to 450℃ at a rate of 3℃ / min and calcine at a constant temperature for 3 hours to obtain mixture d;

[0072] 4) Take 30.2g of nickel nitrate, 29.1g of ammonium hydrogen phosphate and water to prepare impregnation solution e. Place the mixture d in impregnation solution e and impregnate for 1 hour. Then dry at 80℃, then heat to 180℃ at a rate of 3℃ / min and calcine at a constant temperature for 2 hours. Then heat to 450℃ at a rate of 3℃ / min and calcine at a constant temperature for 2.5 hours to obtain the catalyst. The catalyst is labeled as B.

[0073] Example 3

[0074] The preparation method of the hydrogenation catalyst in this embodiment includes the following steps:

[0075] 1) Take 61.8g of sepiolite and soak it in deionized water. After sedimentation and removal of impurities, substance a is obtained.

[0076] 2) Mix substance a with 19.0g metatitanic acid evenly, add 4g sucrose, 3g citric acid, 3g nitric acid and 55g water, shape, dry at 100℃, heat to 190℃ at a rate of 2℃ / min and calcine at a constant temperature for 1.5h, then heat to 350℃ at a rate of 3℃ / min and calcine at a constant temperature for 4h to obtain carrier b;

[0077] 3) Prepare a mixed aqueous solution of cobalt nitrate and nickel nitrate with a C value of 0.83, and add 13.5g of molybdenum nitrate, 7.28g of citric acid and 52g of water to obtain impregnation solution c. Place the carrier b in impregnation solution c and impregnate for 1.5 hours, then dry at 100℃, then heat to 250℃ at a rate of 3℃ / min and calcine at a constant temperature for 2 hours, and then heat to 450℃ at a rate of 3℃ / min and calcine at a constant temperature for 3 hours to obtain mixture d;

[0078] 4) Take 24.1g of nickel nitrate, 21.9g of ammonium hydrogen phosphate and water to prepare impregnation solution e. Place the mixture d in impregnation solution e and impregnate for 1 hour. Then dry at 100℃, then heat to 200℃ at a rate of 2℃ / min and calcine at a constant temperature for 2 hours. Then heat to 450℃ at a rate of 2℃ / min and calcine at a constant temperature for 2.5 hours to obtain the catalyst. The catalyst is labeled C.

[0079] Comparative Example 1

[0080] The difference between this comparative example and the embodiment is that in step 3), the value of C is greater than that in the embodiment.

[0081] The preparation method of the catalyst in this comparative example includes the following steps:

[0082] 1) Take 61.8g of sepiolite and soak it in deionized water. After sedimentation and removal of impurities, substance a is obtained.

[0083] 2) Mix substance a with 19.0g metatitanic acid evenly, add 3g starch, 3g citric acid, 3g nitric acid and 55g water, shape, dry at 100℃, heat to 190℃ at a rate of 2℃ / min and calcine at a constant temperature for 1.5h, then heat to 350℃ at a rate of 3℃ / min and calcine at a constant temperature for 4h to obtain carrier b;

[0084] 3) Prepare a mixed aqueous solution of cobalt nitrate and nickel nitrate with a C value of 1.2, and add 13.5g of molybdenum nitrate, 7.28g of phosphoric acid and 52g of water to obtain impregnation solution c. Place the carrier b in impregnation solution c and impregnate for 1.5 hours, then dry it, and then heat it to 250℃ at a rate of 3℃ / min and calcine it at a constant temperature for 2 hours. Then heat it to 450℃ at a rate of 3℃ / min and calcine it at a constant temperature for 3 hours to obtain mixture d.

[0085] 4) Take 24.1g of nickel nitrate and 21.9g of ammonium hydrogen phosphate and water to prepare impregnation solution e. Place the mixture d in impregnation solution e and impregnate for 1 hour. Then dry it and calcine it at a constant temperature of 200℃ for 2 hours. Then calcine it at a constant temperature of 450℃ for 2.5 hours. The catalyst is obtained. The catalyst is labeled as D.

[0086] Comparative Example 2

[0087] The main difference between this comparative example and the embodiment is that the components of carrier b have been modified.

[0088] The preparation method of the catalyst in this comparative example includes the following steps:

[0089] 1) Take 77.3g of sepiolite and soak it in deionized water. After sedimentation and removal of impurities, substance a is obtained.

[0090] 2) Add 3g polyethylene glycol, 3g citric acid, 3g nitric acid and 55g water to substance a, shape it, dry it at 90℃, heat it to 200℃ at a rate of 2℃ / min and calcine it at a constant temperature for 1h, and then heat it to 350℃ at a rate of 2℃ / min and calcine it at a constant temperature for 4.5h to obtain carrier b.

[0091] 3) Prepare a mixed aqueous solution of cobalt nitrate and nickel nitrate with a C value of 0.83, and add 13.5g of molybdenum nitrate, 7.28g of citric acid and 52g of water to obtain impregnation solution c. Place the carrier b in impregnation solution c and impregnate for 1.5 hours, then dry at 90℃, then heat to 250℃ at a rate of 3℃ / min and calcine at a constant temperature for 2 hours, and then heat to 450℃ at a rate of 3℃ / min and calcine at a constant temperature for 3 hours to obtain mixture d;

[0092] 4) Take 24.1g of nickel nitrate, 21.9g of ammonium hydrogen phosphate and water to prepare impregnation solution e. Place the mixture d in impregnation solution e and impregnate for 1 hour. Then dry at 90℃, then heat to 200℃ at a rate of 2℃ / min and calcine at a constant temperature for 2 hours. Then heat to 450℃ at a rate of 2℃ / min and calcine at a constant temperature for 2.5 hours to obtain the catalyst. The catalyst is labeled as E.

[0093] Comparative Example 3

[0094] The preparation method of the catalyst in this comparative example includes the following steps:

[0095] 1) Take 53.3g of sepiolite and soak it in deionized water. After sedimentation and removal of impurities, substance a is obtained.

[0096] 2) Mix substance a with 13.3g metatitanic acid evenly, add 3g starch, 3g citric acid, 3g nitric acid and 45g water, shape, dry at 90℃, heat to 200℃ at a rate of 2℃ / min and calcine at a constant temperature for 1h, then heat to 350℃ at a rate of 2℃ / min and calcine at a constant temperature for 4.5h to obtain carrier b;

[0097] 3) Prepare a mixed aqueous solution of cobalt nitrate and nickel nitrate with a C value of 1, and add 18.0 g of molybdenum nitrate, 9.71 g of citric acid and 52 g of water to obtain impregnation solution c. Place the carrier b in impregnation solution c and impregnate for 1.5 hours, then dry at 90°C, then heat to 250°C at a rate of 3°C / min and calcine at a constant temperature for 2 hours, and then heat to 450°C at a rate of 3°C / min and calcine at a constant temperature for 3 hours to obtain mixture d;

[0098] 4) Take 14.9g of nickel nitrate, 13.5g of ammonium hydrogen phosphate and water to prepare impregnation solution e. Place the mixture d in impregnation solution e and impregnate for 1 hour. Then dry at 90℃, then heat to 180℃ at a rate of 3℃ / min and calcine at a constant temperature for 2 hours. Then heat to 450℃ at a rate of 3℃ / min and calcine at a constant temperature for 2.5 hours to obtain the catalyst. The catalyst is labeled F.

[0099] In the examples and comparative examples, the concentration of the impregnation solution c in step 3) and the porosity of the carrier b satisfy the following relationship: C=C1 / C2, A=C×ґ / Ԑ;

[0100] C1 is the mass concentration of cobalt ions in impregnation solution c; C2 is the mass concentration of nickel ions in impregnation solution c; ґ is the catalyst tortuosity factor; Ԑ is the porosity of support b; A is the influence factor; C is the mass concentration ratio of cobalt and nickel ions; the values ​​of C, A, ґ, and Ԑ are detailed in Table 1.

[0101] Table 1 Catalyst composition

[0102] .

[0103] Performance testing

[0104] use Figure 1 The small-scale pressurized evaluation apparatus and evaluation conditions shown were used to test the hydrocarbon steam reforming catalysts prepared in the above examples and comparative examples. The catalyst was packed in... Figure 1 In reactor 4.

[0105] Test 1: The catalyst AF obtained from the examples and comparative examples was tested at a system pressure of 3.0 MPa and a carbon space velocity of 3000 h⁻¹. -1 The feed temperature was 200℃, then the temperature was increased to 250℃ for hydrogenation evaluation. The reactant was 200ppm thiophene prepared with No. 6 solvent oil. 10ml of catalyst was loaded, and the reaction was run for 100 hours. The catalyst conversion formula is as follows, and the evaluation results are shown in the table below:

[0106] Catalyst conversion rate formula = (initial concentration - equilibrium concentration) / initial concentration.

[0107] Table 2 Performance Test Results

[0108] .

[0109] As can be seen from Table 2, the thiophene conversion rate at 250℃ in Examples 1-3 is significantly higher than that in Comparative Examples 1-3. The high thiophene conversion rate at 250℃ proves that the present invention can enable the catalyst to be directly activated in the feed oxidation state at 200℃, with high low-temperature activity and high conversion rate.

[0110] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A process for the preparation of a hydrogenation catalyst, characterized in that The method comprises the following steps: 1) soaking the meerschaum in deionized water, settling, and removing impurities to obtain material a; 2) mixing the material a with metatitanic acid, adding a pore expander, a binder, and water, shaping, drying, and calcining to obtain carrier b; 3) preparing a mixed solution of cobalt salt and nickel salt, and adding molybdenum salt, a complexing agent, and a solvent to obtain impregnating liquid c, immersing the carrier b in the impregnating liquid c, and then drying and calcining to obtain mixture d; 4) preparing an impregnating liquid e of nickel salt and ammonium hydrogen phosphate salt and a solvent, immersing the mixture d in the impregnating liquid e, and then drying and calcining to obtain the catalyst. In step 2), the carrier b is a titanium dioxide-meerschaum composite carrier. In step 3), the concentration of the impregnating liquid c and the porosity of the carrier b satisfy the following relationship: C=C1 / C2, A=C×ґ / Ԑ C1 is the mass concentration of cobalt ions in the impregnating liquid c; C2 is the mass concentration of nickel ions in the impregnating liquid c; ґ is the catalyst tortuosity factor; Ԑ is the porosity of the carrier b; A is the influence factor; C is the mass concentration ratio of cobalt ions to nickel ions; The value range of C is 0.1-1, and the value range of A is 2.5-5.

9. The value range of ґ is 2-7.7, and the value range of Ԑ is 1.3-1.

62. The catalyst contains 12.5-22% of active components by mass percentage, and the active components are calculated based on nickel phosphide, cobalt oxide, molybdenum oxide, and nickel oxide, wherein the content of nickel phosphide accounts for 4-6% of the mass of the catalyst, the content of molybdenum oxide accounts for 6-10% of the mass of the catalyst, the content of cobalt oxide accounts for 1-3% of the mass of the catalyst, the content of nickel oxide accounts for 1.5-3% of the mass of the catalyst, and the remaining components of the catalyst are the composite carrier.

2. The process for preparing a hydrogenation catalyst according to claim 1, characterized by: In step 2), the mass ratio of metatitanic acid to meerschaum in step 1) is 1:3-1:

8.

3. The method for preparing a hydrogenation catalyst according to claim 1, characterized in that: In step 3), the mass ratio of molybdenum salt, cobalt salt, and nickel salt is 1:0.67-1.2:1-1.

2.

4. The method of claim 1, wherein: In step 3), the complexing agent is one or two of ammonia, citric acid, and phosphoric acid.

5. The process for preparing a hydrogenation catalyst according to claim 1, characterized by: In step 3), the specific operation of calcining is as follows: increasing the temperature to 180-250℃ at a rate of 1-4℃ / min, constant temperature calcining for 1-2h, then increasing the temperature to 350-450℃ at a rate of 1-4℃ / min, and constant temperature calcining for 2-3h.

6. The process for preparing a hydrogenation catalyst according to claim 1, characterized by: In step 4), the mass ratio of nickel salt to ammonium hydrogen phosphate salt is 0.4-2.0:

1.

7. The method of claim 1, wherein: In step 4), the specific operation of calcining is as follows: increasing the temperature to 180-200℃ at a rate of 1-4℃ / min, constant temperature calcining for 1-2h, then increasing the temperature to 400-500℃ at a rate of 1-4℃ / min, and constant temperature calcining for 2-3h.

8. The hydrogenation catalyst obtainable by the process according to any one of claims 1 to 7, characterized in that: The active components of the catalyst are distributed in multiple layers from the outside of the carrier to the inside of the carrier, the outermost layer of the core is nickel phosphide, the middle layer of the shell is active metal components of nickel oxide and molybdenum oxide, and the core is molybdenum oxide and cobalt oxide.

Images