Preparation method of fixed bed hydrogenation catalyst and application thereof

Abstract

The application provides a catalyst and a preparation method and application thereof, and the preparation method comprises the following steps: first, a pore size adjustment treatment is performed on a spherical full-silicon molecular sieve carrier to obtain carriers with different pore size distributions; then, a CVD reaction is performed by using N2 to carry steam of molten Ni salt, Cr salt and Fe salt into a quartz tube filled with the dried carriers; then, the molecular sieve spheres after the reaction are calcined in N2 to obtain Ni-Cr-FeO x @Si-molecular sieve; and then, H2 or CO is used for reduction to obtain a Ni-Cr-Fe@Si-molecular sieve catalyst. The catalysts with different pore sizes are mixed in a specific proportion and then applied to a BYD fixed-bed hydrogenation process for preparing BDO, and the hydrogenation activity and product selectivity are high, the selectivity for BDO can reach > 99%, the amount of butanol generated is < 0.9%, and the amount of TBA generated is < 0.1%.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of hydrogenation catalysts and its preparation technology, and particularly relates to a preparation method and application of a high-efficiency hydrogenation catalyst for butyne glycol to butanediol. BACKGROUND

[0002] 1,4-Butanediol (BDO) is an important organic synthesis intermediate, widely used and in great demand in the market. Its downstream products include polytetramethylene glycol ether (PTMEG), polybutylene terephthalate (PBT), tetrahydrofuran (THF), gamma-butyrolactone (GBL), etc., all of which are high-value chemical products.

[0003] BDO preparation processes include acetylene aldehyde method, butadiene acetoxylation method, dichlorobutene hydrolysis method, allyl alcohol hydroformylation method and maleic anhydride hydrogenation method, etc.; the vigorous development of coal chemical industry in China provides relatively abundant raw materials for the acetylene aldehyde method, so the Reppe synthesis method is the most widely used method for industrial production of BDO at present. This process uses acetylene and formaldehyde as raw materials, first synthesizes 1,4-butyne glycol (BYD) under the action of a copper catalyst, and then prepares BDO by catalytic hydrogenation of BYD. The preparation of BDO from BYD hydrogenation is a series of reactions. First, BYD is hydrogenated to generate 1,4-butene diol (BED), and then BED is hydrogenated to generate BDO. The intermediate product BED in the hydrogenation process can be isomerized to generate gamma-hydroxybutyraldehyde (gamma-HALD), which can further hydrolyze to generate 2-butenol, n-butyraldehyde, n-butanol, etc. Gamma-HALD itself undergoes aldol condensation to generate long-chain byproducts and furan byproducts. Therefore, improving the reaction rate of BED hydrogenation to generate BDO and reducing the accumulation of BED and gamma-HALD in the reaction system can reduce the generation of byproducts.

[0004] Currently, the catalytic hydrogenation of BYD to prepare BDO in industry is divided into two-stage hydrogenation and one-stage hydrogenation processes. In the two-stage hydrogenation process, the first stage is the low-pressure hydrogenation of BYD in a suspension bed or slurry bed reactor to obtain a BDO crude liquid, the reaction temperature is 60-70℃, the reaction pressure is 2-2.5MPa, and a conventional powder Raney nickel catalyst is usually selected. The second stage is the high-pressure hydrogenation of the BDO crude liquid containing a small amount of hydrogenated unsaturated carbonyl compounds in a fixed bed reactor, the reaction temperature is 120-150℃, the reaction pressure is 12-20MPa, and a supported nickel catalyst is usually used in industry. The main purpose of hydrogenation is to further hydrogenate the small amount of unsaturated carbonyl compounds generated in the first stage of hydrogenation to convert them all into BDO. The one-stage hydrogenation process is the direct liquid-phase hydrogenation reaction of BYD solution in a fixed bed reactor, the reaction temperature is 120-150℃, the reaction pressure is relatively high, and is 23-35MPa. The fixed bed Raney catalyst is used in industrialization. This process has a shorter flow process, but the reaction pressure is very high, resulting in large equipment investment.

[0005] Patent CN101306368A discloses a two-step hydrogenation catalyst for the production of butyrynethiol from butyne glycol. The patent uses an impregnation method to prepare a catalyst containing 5-25% nickel and 0.001-6% promoter. According to the examples, the reaction conditions are: temperature 120℃ and reaction pressure 12 MPa. The reaction temperature and pressure are both relatively high, and the BYD conversion rate is relatively low, only about 80%.

[0006] Patent CN201210212109.2 discloses a method for preparing and activating a special powdered Raney nickel catalyst for the hydrogenation of BYD to BDO. The method involves adding 0.1-2 wt% of a modified metal X (X being Mg, B, Sr, Cr, S, Ti, La, Sn, W, Mo, or Fe) during the smelting of a nickel-aluminum alloy, and then activating the catalyst using a conventional sodium hydroxide (NaOH) alkaline extraction method. The catalyst prepared by this patent using the alkaline extraction method has a small specific surface area and a simple pore structure, resulting in low hydrogenation activity. This leads to a high concentration of the BYD hydrogenation intermediate BED (1,4-butenediol) in the reactor, increasing side reactions. When the BYD conversion rate is 98-100%, the BDO selectivity is <95%, with a significant amount of butanol and acetal recombinants being generated.

[0007] CN106140196B discloses a hydrogenation catalyst for the preparation of BDO from BYD and a method for the preparation of BDO from BYD. The method includes the preparation of metal alloy particles; activation treatment of the metal alloy particles using an alkaline solution; washing the activated metal alloy particles with deionized water; subsequent impregnation modification treatment of the washed metal alloy particles using a molybdenum salt aqueous solution; and washing the metal alloy particles after subsequent impregnation modification treatment with deionized water to obtain a granular Raney nickel catalyst. Molybdenum salt modification can improve the catalytic hydrogenation activity of the metal alloy particle catalyst for BYD in a fixed-bed reactor. However, the molybdenum active component loaded by the impregnation method has poor stability and is easily lost, resulting in low catalyst stability.

[0008] In summary, based on the problems existing in the above-mentioned technologies, there is a need to develop a novel catalyst for the one-step hydrogenation of BYD in a fixed bed process, which can achieve high conversion and selectivity of BYD, as well as good activity stability and long lifespan, to meet the requirements of large-scale continuous BYD catalytic hydrogenation processes. This is of great significance for meeting the growing market demand for BDO. Summary of the Invention

[0009] The purpose of this invention is to provide a method for preparing and applying a fixed-bed hydrogenation catalyst. The preparation method is simple and easy to scale up for industrial production. The catalyst is used in the hydrogenation of 1,4-butynediol to prepare 1,4-butanediol, which can achieve high selectivity for BDO and high conversion rate for BYD, reduce side reactions, lower production costs, and improve economic efficiency.

[0010] To achieve this objective, the present invention adopts the following technical solution:

[0011] A method for preparing a fixed-bed hydrogenation catalyst includes the following steps:

[0012] (1) Pore enlargement treatment: The spherical molecular sieve support is added to the high-pressure hydrothermal reactor and treated with a macromolecular organic amine solution. The pore size of the support is controlled by adjusting the concentration of the organic amine solution, the treatment temperature and time. After treatment, the support with different pore size distribution is prepared by drying and calcination.

[0013] (2) Chemical vapor deposition reaction: Using N2 as the carrier gas, molten Ni salt, Cr salt and Fe salt are introduced into the reaction tube filled with the carrier prepared in step (1). The Ni salt, Cr salt and Fe salt vapor react with the hydroxyl groups on the surface of the molecular sieve to obtain a mixture of Ni salt, Cr salt and Fe salt bonded to oxygen on the surface of the molecular sieve.

[0014] (3) Calcination: The mixture of Ni salt, Cr salt and Fe salt obtained in step (2) and oxygen bonded to the surface of the molecular sieve is calcined in a N2 atmosphere to obtain Ni-Cr-FeO. x The composite oxide loaded on the surface of the support yields Ni-Cr-FeO. x @Si-molecular sieve eggshell-type composite oxide, where x is determined by the number of metal elements different from oxygen and their degree of oxidation;

[0015] (4) Reduction: Ni-Cr-FeO is reduced by H2 or CO. x Ni-Cr-Fe@Si-molecular sieve catalyst was obtained by reduction of @Si-molecular sieve.

[0016] (5) Compounding: Catalysts with different pore sizes are loaded into a three-dimensional mixer in a specific ratio and mixed and compounded to obtain catalysts with different hydrogenation performances, which are then used for loading into the upper, middle and lower layers of the catalyst bed in a fixed bed reactor.

[0017] In step (1) of this invention, the carrier is a spherical all-silica molecular sieve with an initial pore size of 2-4 nm and a specific surface area of ​​500-800 m². 2 / g, Al2O3 content <200ppm, particle diameter 3.0~7.0mm;

[0018] The macromolecular organic amine is a straight-chain macromolecular organic amine, such as DMDA (N,N-dimethyldodecylamine), N,N-dimethylundecylamine, N,N-dimethyltetradecylamine, etc.; the concentration of the macromolecular organic amine aqueous solution is 1.5-15.0 wt%, the treatment temperature is 120-170℃, the pore size distribution of the carrier prepared by the macromolecular organic amine aqueous solution treatment is 4-15 nm; the calcination temperature is 350-550℃.

[0019] The Ni salt, Cr salt, and Fe salt in step (2) of this invention are all low-boiling-point metal salts, wherein the Ni salt is nickel nitrate, the Cr salt is chromium nitrate, and the Fe salt is ferric nitrate; the Ni salt, Cr salt, and Fe salt do not contain water of crystallization.

[0020] The loading amount of Ni on the carrier described in this invention is 5.0–25.0 wt%, preferably 8.0–20.0 wt%, based on the weight of the carrier; the molar ratio of Ni, Cr, and Fe elements is 1:(0.01–0.15):(0.01–0.15), preferably 1:(0.05–0.1):(0.05–0.1). The boiling points of the Ni, Cr, and Fe salts in step (1) of this invention are 83–150 °C, which can be achieved by any heating method known in the art. The flow rate of N2 in the reaction tube is 0.05–2.0 cm / s, preferably 0.50–1.35 cm / s. The metal salts vaporize at 83–150 °C, and N2 carries the metal salt vapor to the surface of the silica gel to begin the chemical vapor deposition reaction. The reaction temperature is 150–260 °C. The metal salt vapors react with the associated hydroxyl groups on the surface of the carrier to carry out the following reaction:

[0021] ~O-Si-OH+Ni(NO3)2→~O-Si-O-Ni-NO3

[0022] ~O-Si-OH+Cr(NO3)3→~O-Si-O-Cr-(NO3)2

[0023] ~O-Si-OH+Fe(NO3)3→~O-Si-O-Fe-(NO3)2.

[0024] In step (3) of this invention, the calcination temperature in an N2 atmosphere is 300–500°C, preferably 350–450°C, the calcination time is 10–100 min, preferably 30–60 min, and the N2 flow rate is 0.05–2.0 cm / s, preferably 0.50–1.35 cm / s. In step (3) of this invention, calcination is first performed in an N2 atmosphere to allow some metal ions (Ni, Cr, Fe) to enter the Si-O tetrahedral lattice, while simultaneously removing NO3. - (transformed into NO) x (x = 1 or 2).

[0025] In step (4) of this invention, H2 or CO can be provided as a pure gas, or mixed with an optional inert gas to form a mixed gas, preferably in the form of an H2 / N2 mixed gas or a CO / N2 mixed gas, wherein the volume fraction of H2 or CO in the mixed gas is 1v% to 20v%, preferably 5v% to 10v%, based on the volume of the mixed gas. In step (4) of this invention, the linear velocity of the H2 / N2 mixed gas or the CO / N2 mixed gas in the reaction tube is 1.0 to 5.0 cm / s, preferably 3.0 to 5.0 cm / s. In step (4) of this invention, the reduction temperature is 300 to 600°C, preferably 400 to 550°C, and the time is 1 to 5 hours, preferably 2 to 3 hours.

[0026] The eggshell-type Ni-Cr-Fe@Si molecular sieve catalyst of the present invention has a pore size of 4.0–15.0 nm. Catalysts with pore sizes of 4–6 nm, 7–10 nm, and 11–15 nm are mixed in a mass ratio of 1–3:2–4:3–7 and then loaded into the upper, middle, and lower layers of the catalyst bed in a fixed-bed reactor for use. Preferably, the mass of catalyst in the upper, middle, and lower layers is the same.

[0027] The catalyst is used to catalyze the hydrogenation of unsaturated alcohols to prepare saturated polyols; preferably, the hydrogenation reaction is carried out in a fixed-bed reactor, wherein the unsaturated alcohol is 1,4-butynediol and the polyol is 1,4-butanediol.

[0028] The catalyst prepared by this invention can achieve efficient hydrogenation of 1,4-butynediol under high load in a fixed-bed reactor.

[0029] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) Compared with traditional Raney nickel catalyst, the hydrogenation catalyst of the present invention effectively reduces the amount of Ni used in the catalyst, significantly reduces the catalyst cost, and has higher catalytic efficiency;

[0032] (2) The preparation method of the present invention modulates the pore size of molecular sieves, then loads active metal components onto a support through CVD reaction, and prepares a series of catalysts with different pore size distributions through calcination and reduction treatment. Catalysts with different pore sizes have different BYD diffusion and hydrogenation performance. At the same time, the CVD reaction makes the support and metal active center have strong binding force and long catalyst life.

[0033] (3) The catalysts of different pore sizes described in this invention are compounded in a specific ratio and added to a fixed bed reactor to achieve gradient conversion of BYD, which solves the problem of high local BED concentration in the reactor, effectively suppresses the occurrence of side reactions, and achieves BDO selectivity ≥99.0% and BYD conversion rate >99.9%, which can meet the requirements of large-tonnage continuous BDO production process. Detailed Implementation

[0034] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention.

[0035] The pore size distribution of the catalyst prepared in the examples was characterized using a physical adsorption instrument, manufactured by Micromeritics, model ASAP2020.

[0036] The spherical all-silica molecular sieves used in the examples were prepared in-house. The preparation method was as follows: Commercially available MCM-41 molecular sieve powder, guar gum powder, and hydroxypropyl methylcellulose were added to a coating machine, with guar gum powder added at a ratio of 1.5 wt% (based on the molecular sieve mass) and hydroxypropyl methylcellulose added at a ratio of 0.5 wt% (based on the molecular sieve mass). Silica sol and polyvinyl alcohol aqueous solution were added to the coating machine as binders, and the molecular sieve carrier was prepared by spherical rolling. The initial pore size of the prepared molecular sieve was 2–4 nm, and the specific surface area was 500–800 m². 2 / g, Al2O3 content <200ppm, particle diameter 3.0~7.0mm.

[0037] Example 1

[0038] This embodiment provides a catalyst for BYD fixed-bed hydrogenation and its preparation method, the preparation method comprising the following steps:

[0039] (1) 500g of DMDA aqueous solution with a concentration of 1.5% was added to a 1L hydrothermal reactor, 100g of Si-molecular sieve balls were added, and the mixture was placed in a 120℃ oven for hydrothermal treatment for 12h. After drying and calcination at 350℃, a spherical molecular sieve support with a pore size of 4-5nm was prepared.

[0040] Using the same process, Si-molecular sieve balls were hydrothermally treated with 8% and 15% DMDA aqueous solutions in ovens at 150℃ and 170℃, respectively, and then dried and calcined at 350℃ to prepare supports with pore sizes of 9-10nm and 14-15nm.

[0041] (2) 100g of the carrier prepared in step (1) was loaded into a quartz reaction tube with an inner diameter of 20mm. The temperature of the reaction tube was 200℃. The silica gel microspheres were purged with N2 at a flow rate of 300ml / min (the linear velocity of N2 in the reaction tube was 1.59cm / s) for 180min. 24.91g Ni(NO3)2, 0.37g Cr(NO3)3, and 0.34g Fe(NO3)3 were added to a vaporization tank. The temperature of the vaporization tank was set to 85-150℃ depending on the type of metal nitrate. The N2 was switched to the vaporization pipeline system. The molten Ni, Cr, and Fe salts were introduced into the reaction tube with N2 at a flow rate of 150ml / min (the linear velocity of N2 in the reaction tube was 0.5cm / s) to react chemically with the silica gel microspheres. After all the Ni, Cr, and Fe salts in the gasification tank were introduced into the reaction system, they were calcined for 45 minutes at 400°C in a N2 atmosphere with a flow rate of 150 ml / min (the linear velocity of N2 in the reaction tube was 0.8 cm / s) to obtain Ni-Cr-FeO. x @Si-molecular sieve eggshell-type composite oxide.

[0042] (3) The eggshell-shaped composite oxide obtained by calcination in step (2) is loaded into a fixed-bed reactor for reduction at a temperature of 450℃. A mixture of 10% H2 and nitrogen at a flow rate of 800 ml / min (linear velocity of 1.89 cm / s) is used to reduce Ni-Cr-FeO. x The reduction of @Si molecular sieves takes 3 hours to obtain Ni-Cr-Fe@Si molecular sieve catalyst with pore size distribution of 4-5 nm, 9-10 nm and 14-15 nm.

[0043] (4) The catalyst prepared in step (3) is thoroughly mixed in a three-dimensional mixer according to the mass ratio of 1:2:7, 2:3:5 and 3:4:3 according to the pore size from small to large. The mixture is then filled into the upper, middle and lower parts of the high-pressure fixed bed reactor, with each part having the same mass of catalyst (the same applies to the following examples).

[0044] The catalyst prepared in step (4) was evaluated for its performance in the hydrogenation of BYD to BDO. The reaction temperature was 120℃, the reaction pressure was 10.0 MPa, and the BYD feed mass hourly space velocity was 0.3 h⁻¹. -1 With a hydrogen-to-oil ratio of 50:1, continuous operation for 100 hours, and gas chromatography analysis of samples, the BYD conversion rate reached 100%, the selectivity for BDO was 99.1%, the butanol production was 0.72%, and the heavy component TBA production was 0.18%.

[0045] Example 2

[0046] This embodiment provides a catalyst for BYD fixed-bed hydrogenation and its preparation method, the preparation method comprising the following steps:

[0047] (1) 500g of 3% DMDA aqueous solution was added to a 1L hydrothermal reactor, 100g of Si-molecular sieve balls were added, and the mixture was placed in a 120℃ oven for hydrothermal treatment for 12h. After drying and calcination at 350℃, a spherical molecular sieve support with a pore size of 5-6nm was prepared.

[0048] Using the same process, 10% and 13% aqueous solutions of DMDA were applied at 150°C and 170°C, respectively.

[0049] Si-molecular sieve spheres were hydrothermally treated in an oven, and then dried and calcined at 350℃ to prepare supports with pore sizes of 7-8 nm and 11-13 nm.

[0050] (2) 100g of the carrier prepared in step (1) was placed into a quartz reaction tube with an inner diameter of 20mm. The temperature of the reaction tube was 200℃. The silica gel microspheres were purged with N2 at a flow rate of 400ml / min (the linear velocity of N2 in the reaction tube was 1.59cm / s) for 180min. 46.69g Ni(NO3)2, 3.19g Cr(NO3)3, and 3.49g Fe(NO3)3 were added to the vaporization tank. The temperature of the vaporization tank was set to 85-150℃ depending on the type of metal nitrate. The N2 was switched to the vaporization pipeline system, and N2 with a flow rate of 250ml / min (the linear velocity of N2 in the reaction tube was 0.5cm / s) was used to carry the molten Ni, Cr, and Fe salts into the reaction tube to react chemically with the silica gel microspheres. After all the Ni, Cr, and Fe salts in the gasification tank were introduced into the reaction system, they were calcined for 45 minutes at 400°C in a N2 atmosphere with a flow rate of 150 ml / min (the linear velocity of N2 in the reaction tube was 0.8 cm / s) to obtain Ni-Cr-FeO. x @Si-molecular sieve eggshell-type composite oxide.

[0051] (3) The eggshell-shaped composite oxide obtained by calcination in step (2) is loaded into a fixed-bed reactor for reduction at a temperature of 450℃. A mixture of 10% H2 and nitrogen at a flow rate of 800 ml / min (linear velocity of 1.89 cm / s) is used to reduce Ni-Cr-FeO. x The reduction of @Si molecular sieves takes 3 hours to obtain Ni-Cr-Fe@Si molecular sieve catalyst with pore size distribution of 5-6 nm, 7-8 nm and 11-13 nm.

[0052] (4) The catalysts prepared in step (3) are thoroughly mixed in a three-dimensional mixing center according to the pore size from small to large at ratios of 1:2:7, 2:3:5 and 3:3:4, and then filled into the upper, middle and lower parts of the high-pressure fixed bed reactor respectively.

[0053] The performance of the catalyst prepared in step (4) to produce BDO by hydrogenation of BYD was evaluated under the same conditions as in Example 1. After continuous operation for 100 hours, samples were taken for gas chromatography analysis. The conversion rate of BYD reached 100%, the selectivity for BDO was 99.0%, the amount of butanol produced was 0.85%, and the amount of heavy component TBA produced was 0.15%.

[0054] Example 3

[0055] This embodiment provides a catalyst for BYD fixed-bed hydrogenation and its preparation method, the preparation method comprising the following steps:

[0056] (1) 500g of N,N-dimethyltetradecylamine aqueous solution with a concentration of 3% was added to a 1L hydrothermal reactor, 100g of Si-molecular sieve balls were added, and the mixture was placed in a 120℃ oven for hydrothermal treatment for 12h. After drying and calcination at 350℃, a spherical molecular sieve support with a pore size of 5-6nm was prepared.

[0057] Using the same process, Si-molecular sieve balls were hydrothermally treated for 12 hours in ovens at 150℃ and 170℃ with N,N-dimethyltetradecylamine aqueous solutions of 10% and 13% concentrations, respectively, and then dried and calcined at 350℃ to obtain supports with pore sizes of 8-9 nm and 13-15 nm.

[0058] (2) 100g of the carrier prepared in step (1) was placed into a quartz reaction tube with an inner diameter of 20mm. The temperature of the reaction tube was 200℃. The silica gel microspheres were purged with N2 at a flow rate of 400ml / min (the linear velocity of N2 in the reaction tube was 1.59cm / s) for 180min. 62.26g Ni(NO3)2, 9.15g Cr(NO3)3, and 8.66g Fe(NO3)3 were added to the vaporization tank. The temperature of the vaporization tank was set to 85-150℃ depending on the type of metal nitrate. The N2 was switched to the vaporization pipeline system, and N2 at a flow rate of 300ml / min (the linear velocity of N2 in the reaction tube was 0.5cm / s) was used to carry the molten Ni, Cr, and Fe salts into the reaction tube to react chemically with the silica gel microspheres. After all the Ni, Cr, and Fe salts in the gasification tank were introduced into the reaction system, they were calcined for 45 minutes at 400°C in a N2 atmosphere with a flow rate of 150 ml / min (the linear velocity of N2 in the reaction tube was 0.8 cm / s) to obtain Ni-Cr-FeO. x @Si-molecular sieve eggshell-type composite oxide.

[0059] (3) The eggshell-shaped composite oxide obtained by calcination in step (2) is loaded into a fixed-bed reactor for reduction at a temperature of 450℃. A mixture of 10% H2 and nitrogen at a flow rate of 800 ml / min (linear velocity of 1.89 cm / s) is used to reduce Ni-Cr-FeO. x The reduction of @Si molecular sieves takes 3 hours to obtain Ni-Cr-Fe@Si molecular sieve catalyst with pore size distribution of 5-6 nm, 8-9 nm and 13-15 nm.

[0060] (4) The catalysts prepared in step (3) are thoroughly mixed in a three-dimensional mixing center according to the pore size from large to small in the proportions of 1:2:7, 2:3:5 and 3:4:3, and then filled into the upper, middle and lower parts of the high-pressure fixed bed reactor respectively.

[0061] The performance of the catalyst prepared in step (4) to produce BDO by hydrogenation of BYD was evaluated under the same conditions as in Example 1. After continuous operation for 100 hours, samples were taken for gas chromatography analysis. The conversion rate of BYD reached 100%, the selectivity for BDO was 99.2%, the amount of butanol produced was 0.70%, and the amount of heavy component TBA produced was 0.10%.

[0062] Example 4

[0063] This embodiment provides a catalyst for BYD fixed-bed hydrogenation and its preparation method. Except that the compounding ratio described in step (4) is adjusted to 1:3:6, 3:3:4 and 2:2:6 and then fully mixed in a three-dimensional mixer and filled into the upper, middle and lower parts of the high-pressure fixed-bed reactor, all other conditions are the same as in Example 1.

[0064] The performance of the catalyst prepared in this example for the hydrogenation of BYD to BDO was evaluated under the same conditions as in Example 1. After continuous operation for 100 hours, samples were taken for gas chromatography analysis. The BYD conversion rate reached 100%, the selectivity for BDO was 98.7%, the butanol production was 1.1%, and the heavy component TBA production was 0.20%.

[0065] Comparative Example 1

[0066] This comparative example provides a catalyst for fixed-bed hydrogenation of BYD and its preparation method. Except for removing the Si-molecular sieve pore-expansion step (1), all other conditions are the same as in Example 1.

[0067] The performance of the catalyst prepared in this comparative example for the hydrogenation of BYD to BDO was evaluated under the same conditions as in Example 1. After continuous operation for 100 hours, samples were taken for gas chromatography analysis. The BYD conversion rate reached 98.8%, the selectivity for BDO was 95.2%, the butanol production was 3.7%, and the heavy component TBA production was 1.1%.

[0068] Comparative Example 2

[0069] This comparative example provides a catalyst for fixed-bed hydrogenation of BYD and its preparation method. Except for step (4), which does not involve compounding, catalysts with pore sizes of 4-5 nm, 9-10 nm and 14-15 nm are directly loaded into the upper, middle and lower parts of the reactor, respectively. All other conditions are the same as in Example 1.

[0070] The performance of the catalyst prepared in this comparative example for the hydrogenation of BYD to BDO was evaluated under the same conditions as in Example 1. After continuous operation for 100 hours, samples were taken for gas chromatography analysis. The BYD conversion rate reached 100%, the selectivity for BDO was 97.5%, the butanol production was 2.0%, and the heavy component TBA production was 0.5%.

[0071] Comparative Example 3

[0072] This comparative example provides a catalyst for fixed-bed hydrogenation of BYD and its preparation method. Except that the chemical vapor deposition method for loading Ni, Cr, and Fe active centers in step (2) is replaced by impregnation of the support with salt solutions of the three metals to prepare the catalyst (after impregnation, it is treated in an N2 atmosphere at 400°C with a flow rate of 150 ml / min (the linear velocity of N2 in the reaction tube is 0.8 cm / s) for 180 min), all other conditions are the same as in Example 1.

[0073] The performance of the catalyst prepared in this comparative example for the hydrogenation of BYD to BDO was evaluated under the same conditions as in Example 1. After continuous operation for 100 hours, samples were taken for gas chromatography analysis. The BYD conversion rate was 96.5%, the selectivity for BDO was 92.3%, the butanol production was 4.6%, and the heavy component TBA production was 3.1%.

[0074] Comparative Example 4

[0075] This comparative example uses 300.0g of MC-507 commercial catalyst (purchased from EVONIK, brand name: MC-507).

[0076] The performance of this comparative catalyst in the hydrogenation of BYD to BDO was evaluated under the same conditions as in Example 1. After continuous operation for 100 hours, samples were taken for gas chromatography analysis. The BYD conversion rate was 99.5%, the selectivity for BDO was 97.2%, the butanol production was 2.0%, and the heavy component TBA production was 0.80%.

[0077] Comparative Example 5

[0078] This comparative example uses 300.0g of commercial Ni / Al2O3 catalyst (purchased from Xunkai, brand name: NiCAT-3000Q).

[0079] The performance of this comparative catalyst in the hydrogenation of BYD to BDO was evaluated under the same conditions as in Example 1. After continuous operation for 100 hours, samples were taken for gas chromatography analysis. The BYD conversion rate reached 100%, the selectivity for BDO was 88.1%, the butanol production was 8.7%, and the heavy component TBA production was 3.2%.

Claims

1. A method for preparing a catalyst for fixed-bed hydrogenation, characterized in that, The preparation method includes the following steps: (1) The all-silica molecular sieve support is treated with a macromolecular organic amine solution to obtain supports with different pore size distributions; the macromolecular organic amine is selected from N,N-dimethyldodecylamine, N,N-dimethylundecylamine, and N,N-dimethyltetradecylamine. (2) Using N2 as a carrier gas, the molten Ni salt, Cr salt and Fe salt are introduced into the reaction tube containing the carrier prepared in step (1) to obtain a mixture of Ni salt, Cr salt and Fe salt bonded to oxygen on the surface of the molecular sieve. (3) The mixture from step (2) is calcined in a N2 atmosphere to obtain Ni-Cr-FeO. x Composite oxides loaded on the surface of a carrier; (4) Use H2 or CO to treat Ni-Cr-FeO x The composite oxide supported on the surface of the support is reduced to obtain Ni-Cr-Fe@Si-molecular sieve catalyst; (5) Catalysts with different pore sizes are mixed and compounded. Catalysts with pore sizes of 4-6 nm, 7-10 nm and 11-15 nm are mixed in a mass ratio of 1-3:2-4:3-7 and then loaded into the upper, middle and lower layers of the catalyst bed in the fixed bed reactor for use.

2. The method according to claim 1, characterized in that, The initial pore size of the all-silica molecular sieve in step (1) is 2-4 nm, and the specific surface area is 500-800 m². 2 / g, Al2O3 content <200ppm, particle diameter 3.0~7.0mm.

3. The method according to any one of claims 1-2, characterized in that, The carrier prepared by step (1) through treatment with aqueous solution of macromolecular organic amine has a pore size distribution of 4–15 nm.

4. The method according to claim 1, characterized in that, In step (2), the loading amount of Ni on the support is 5.0 to 25.0 wt%, based on the weight of the support; the molar ratio of Ni, Cr, and Fe is 1:(0.01 to 0.15):(0.01 to 0.15).

5. The method according to claim 1, characterized in that, In step (3), the calcination temperature is 300-500℃, the calcination time is 10-100min, and the N2 flow rate is 0.05-2.0cm / s.

6. The method according to claim 1, characterized in that, In step (4), the reduction temperature is 300-600℃ and the reduction time is 1-5 hours.

7. The use of the catalyst prepared by the method according to any one of claims 1 to 6 for catalytic hydrogenation of unsaturated alcohols to prepare saturated polyols.

8. A method for preparing saturated polyol compounds by hydrogenation of unsaturated alcohol compounds, wherein, The catalyst used is a catalyst prepared according to any one of claims 1 to 6. The catalyst is used after being mixed according to different pore sizes. The catalysts with pore sizes of 4-6 nm, 7-10 nm and 11-15 nm are mixed in a mass ratio of 1-3:2-4:3-7 and then respectively loaded into the upper, middle and lower layers of the catalyst bed in the fixed bed reactor.

9. The method as described in claim 8, characterized in that, The unsaturated alcohol compound is 1,4-butynediol, and the polyol compound is 1,4-butanediol.