High-selectivity reforming oil hydrogenation catalyst, its preparation method and application

Abstract

The application relates to the field of catalytic materials, and discloses a high-selectivity reforming oil hydrogenation catalyst as well as a preparation method and application thereof. The catalyst comprises an alumina carrier and monocrystal Ni particles, Ni-Si and Ni-Si / SiO2 supported on the carrier. The carrier of the catalyst is loaded with monocrystal Ni particles, Ni-Si and Ni-Si / SiO2. Since the Ni-Si and Ni-Si / SiO2 play a barrier role for the monocrystal Ni particles, and the NiSi and SiO2 in the Ni-Si / SiO2 have strong mutual interaction, the catalyst is applied to the hydrogenation catalytic deolefin of reforming oil, has the advantages of high catalytic activity, high olefin hydrogenation selectivity, low carbon deposition and low cost, and can effectively improve the efficiency, reduce the aromatic loss and significantly prolong the service life in the deolefin process of reforming oil.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of catalytic materials, in particular to a high-selectivity reforming oil hydrogenation catalyst and a preparation method and application thereof. BACKGROUND

[0002] Catalytic reforming is one of the main processes for producing aromatic hydrocarbons. After extraction separation, the reforming oil can produce benzene, toluene, xylene (BTX) and other products. Currently, 70-80% of the BTX in the world is derived from the catalytic reforming process. With the continuous development of catalyst technology and catalytic reforming process, especially the progress of multi-metallic catalysts and low-pressure continuous reforming technology, the aromatic hydrocarbon yield and production efficiency are improved, but the olefin content in the reforming oil is also increased. These olefins not only affect the quality of the reforming oil, but also pollute the subsequent extraction solvent; during processing, olefins are prone to deposit on the surface of the heat exchanger through polymerization, thereby reducing the working efficiency of the heat exchanger; during xylene adsorption separation, olefins enter the pore channels of the molecular sieve adsorbent, thereby affecting the separation effect of the adsorbent. Therefore, the olefins contained in the reforming oil must be removed to a low content to ensure the quality of the aromatic hydrocarbon products and reduce the impact on the subsequent processing equipment.

[0003] Currently, there are two methods for removing olefins from reforming oil: one is catalytic adsorption (molecular sieve, clay and modified clay), which has a short service life of the adsorbent and requires frequent replacement, and the adsorbents such as clay cannot be regenerated, which increases the pressure of solid waste treatment; the other method is hydrogenation catalysis, which generally uses Pt, La and other noble metals as active components for hydrogenation catalysis of reforming oil. This method has the advantages of high catalyst activity, low reaction temperature, small reaction pressure and high volume space velocity ratio, but the catalyst of this method is relatively expensive, and has problems such as easy carbon deposition and short running cycle.

[0004] In order to reduce production costs, scholars have also studied the use of Ni, Co, Mo and other active components for reforming oil hydrogenation catalysis, such as Zhang Kongyuan et al. who prepared a NiO / Al2O3 catalyst by wet kneading method and applied it to the removal of olefins from reforming oil (Zhang Kongyuan, Zheng Yun, He Jinkang, et al. Preparation of NiO / Al2O3 reforming oil selective hydrogenation catalyst by wet kneading method [J]. Petroleum and Chemical Industry, 2022, 51(11): 1277-1283.). These metal elements have abundant reserves and are relatively cheap, which is suitable for large-scale industrial application. However, so far, this method needs to be carried out at a relatively high reaction temperature and a relatively low volume space velocity ratio, resulting in large loss of aromatic hydrocarbons, high energy consumption, and problems such as carbon deposition and deactivation during reaction. SUMMARY

[0005] In order to solve the above technical problems, the application provides a high-selectivity reforming oil hydrogenation catalyst, a preparation method and application thereof.The catalyst of the application is loaded with single-crystal Ni particles, Ni-Si and Ni-Si / SiO2 on an alumina carrier.Because the single-crystal Ni particles are blocked by the Ni-Si and Ni-Si / SiO2, and there is a strong interaction between the Ni-Si and SiO2 in the Ni-Si / SiO2, the catalyst has the advantages of high catalytic activity, high olefin hydrogenation selectivity, low carbon deposition and low cost when applied to the catalytic deolefinization of reforming oil, thereby effectively improving the efficiency, reducing the loss of aromatic hydrocarbons and significantly prolonging the service life in the deolefinization process of reforming oil.

[0006] The specific technical scheme of the application is as follows:

[0007] In the first aspect, the application provides a high-selectivity reforming oil hydrogenation catalyst, which comprises an alumina carrier and single-crystal Ni particles, Ni-Si and Ni-Si / SiO2 loaded on the alumina carrier; the Ni-Si and Ni-Si / SiO2 are distributed between the single-crystal Ni particles.

[0008] The catalyst of the present application is supported by alumina, on which monocrystal Ni particles, Ni-Si and Ni-Si / SiO2 (with the increase of siliconization temperature, the formed silicides involve the following change rule: Ni2Si, NiSi, NiSi2, and the Ni-Si in the catalyst of the present application represents the mixture of the above compounds, mainly NiSi) are uniformly loaded, and the large amount of monocrystal Ni particles are separated by Ni-Si and Ni-Si / SiO2. In the process of hydrogenation of olefins in the reformate, generally, the smaller the size of monocrystal Ni particles, the better the dispersion, and the higher the hydrogenation activity. In the catalyst of the present application, part of Ni is combined with Si to form Ni-Si, which plays a certain isolation role for monocrystal Ni particles, reduces the size of Ni particles, and improves the activity of the reaction. In addition, more importantly, we have found that the above separation can also significantly improve the selectivity of the catalyst to the hydrogenation of olefins. The reason is that the reformate is mainly composed of aromatic hydrocarbons and a small amount of olefins. In the process of hydrogenation of olefins, olefins are adsorbed by unit, that is, they can be activated and react by hydrogenation after occupying one active site on the catalyst; while aromatic hydrocarbons are adsorbed by multiple sites, and they can be hydrogenated after occupying multiple active sites on the catalyst. In the present application, due to the separation of Ni-Si compounds to monocrystal Ni particles, different active sites are far apart, and aromatic hydrocarbon molecules are not easy to occupy multiple active sites of monocrystal Ni at the same time, so that the activity of aromatic hydrocarbon molecules is effectively reduced while the activity of olefins is improved, the selectivity of hydrogenation of olefins in the reformate is improved, and the loss of aromatic hydrocarbons is reduced. At the same time, the separation of Ni-Si compounds to monocrystal Ni particles can also prevent them from combining with each other, so as to reduce the active sites of hydrogenation of olefins, delay deactivation or carbon deposition, and effectively prolong the service life of the catalyst.

[0009] In addition, the reason for selecting Ni-Si and Ni-Si / SiO2 in the present application is also that it can re-adjust the catalytic activity of the catalyst in the olefin hydrogenation reaction. (1) Firstly, in the Ni-Si compound, when the Si atom is inserted into the lattice of Ni, the d-orbital of the Ni atom and the p-orbital of the Si atom interact with each other, causing the energy level to jump by an integer, the d-band to narrow, and the resonance energy level to move in the direction of high binding energy, thereby causing coupling between the energy state of Si and the Ni orbital, and finally forming a unique bonding state that is more closely than both original states. Due to the filling of these bonding orbitals, the bond is strengthened, so that the Ni-Si compound has high electrical and thermal conductivity and strong stability. Moreover, the geometric structure and electronic structure of Ni are changed, thereby showing good reaction activity and high chemical stability; (2) Secondly, the present application finds that Ni-Si and SiO2 in Ni-Si / SiO2 have strong interaction in the olefin hydrogenation reaction. The strong interaction refers to a special synergistic effect existing between the interface of Ni-Si and SiO2, the essence of which is the redistribution of charges and the transmission of mass at the interface of Ni-Si and SiO2, thereby changing the electronic structure and morphology of the catalyst, and then affecting the adsorption behavior of the reactants and the formation of reaction intermediates, and finally changing the overall reaction path and the catalytic performance of the catalyst. When Ni-Si is combined with SiO2, the redistribution of charges occurs at the interface of Ni-Si and SiO2, thereby changing the electronic structure and morphology of the catalyst. Specifically: after the combination of Ni-Si and SiO2, SiO2 can transfer part of the charge to Ni-Si and affect the electron cloud density of the adsorbed gas, thereby adjusting the catalytic activity of the catalyst. The present application team found through research that the Ni-Si / SiO2 with strong interaction can promote the adsorption capacity of hydrogen in the reformate hydrogenation catalytic reaction, improve the reaction activity, and is beneficial to reducing the generation of polyolefins, heavy aromatics and other by-products, thereby reducing the risk of carbon deposition of the catalyst.

[0010] Preferably, the specific surface area of the high-selectivity reformate hydrogenation catalyst is 150-260 m 2 / g, the pore volume is 0.3-0.7 cm 3 / g, and the pores with a pore size of 5-10 nm account for 60-80% of the total pore volume of the catalyst.

[0011] In a second aspect, the present application provides a preparation method of a high-selectivity reformate hydrogenation catalyst, comprising the following steps:

[0012] 1) Mix SiO2 powder and modified nickel solution, adjust the pH to be alkaline, heat and react, and after post-treatment, calcination and crushing, obtain NiO / SiO2 composite powder.

[0013] The modified nickel solution contains nickel acetylacetone, ethylene glycol has the function of solvent and dispersant, SiO2 powder is added and mixed, then pH is adjusted to be alkaline and heated to react, at this time, nickel acetylacetone hydrolyzes to precipitate nickel hydroxide from the solvent and uniformly deposit or adsorb on the surface of SiO2 powder, after post-treatment, the solvent and generated organic by-products are removed, then nickel hydroxide is dehydrated to generate nickel oxide by calcination, further impurities are removed, nickel oxide is firmly loaded on SiO2, and NiO / SiO2 composite powder can be obtained after crushing.

[0014] 2) The alumina powder is uniformly mixed with the NiO / SiO2 composite powder, and the aqueous solution of Ni(NO3)2 is stirred into a paste, then dried, ground, shaped and calcined to obtain the alumina loaded with NiO and NiO / SiO2.

[0015] The paste of step 2) contains alumina, NiO / SiO2 composite powder and Ni(NO3)2 and water, after drying, the water is removed, the obtained solid mixture is ground and pressed into a tablet, and then calcined, at this time, the Ni(NO3)2 contained in the shaped solid mixture decomposes to produce NiO at high temperature and is loaded in the alumina and NiO / SiO2 composite powder, thereby the alumina loaded with NiO and NiO / SiO2 is prepared.

[0016] In the present application, two-step method is adopted to load Ni element on the catalyst, respectively in step 1) and step 2), the main reasons are as follows: first, if all the Ni element is added in step 1), the NiO content in the prepared NiO / SiO2 composite powder is too high, which is easy to form a sheet on SiO2, and the produced NiO has too large particle size, and in the subsequent step 2), the NiO cannot be effectively and uniformly dispersed, which seriously reduces the effect of Ni component in the catalyst; second, if all the Ni element is added in step 2), that is, the aqueous solution of nickel nitrate containing all the Ni element is added after the alumina powder is mixed with SiO2 component, in this way, although the alumina loaded with uniformly dispersed NiO can be prepared, the content of the adsorbed NiO on SiO2 is relatively low, which makes the generated Ni-Si / SiO2 component in step 3) too small, and cannot effectively play the effect of strong interaction.

[0017] 3) The alumina loaded with NiO and NiO / SiO2 is first reduced in a reducing atmosphere, then is siliconized in an atmosphere containing SiH4 / H2, and then is reduced in a reducing atmosphere and cooled to obtain the alumina loaded with single-crystal Ni particles and NiSi / SiO2, which is a reforming oil hydrogenation catalyst.

[0018] Under the condition of high temperature and reducing atmosphere, NiO is first reduced into single Ni metal particles, and then part of Ni reacts with silane to form silicide of Ni metal (denoted as Ni-Si compound). Firstly, Ni-Si can play a barrier effect on single crystal Ni particles, thereby improving the selectivity and service life of the catalyst; secondly, Ni-Si has a strong interaction effect with SiO2, thereby being capable of adjusting the catalytic performance.

[0019] Preferably, in step 1), the mass ratio of NiO in the NiO / SiO2 composite powder is 20-30%.

[0020] If the above ratio is too high, the NiO crystal grains loaded in SiO2 are too large and even connected into a sheet, which cannot be effectively dispersed, thereby affecting the catalytic effect; if the ratio is too low, the content of the finally prepared catalyst Ni-Si / SiO2 is too low, and the effect of using strong interaction to improve the reaction effect cannot be achieved.

[0021] Preferably, in step 1), the modified nickel solution is an ethylene glycol solution of nickel acetylacetonate, and the mass ratio of ethylene glycol to nickel acetylacetonate is 20-30:1.

[0022] Preferably, in step 1), the alkaline pH is 9-10.

[0023] Preferably, in step 1), the heating reaction temperature is 110-130℃, and the time is 1-2h.

[0024] Preferably, in step 1), the post-treatment is cooling, filtering and washing to neutral.

[0025] Preferably, in step 1), the calcination temperature is 500-600℃, and the time is 2-3h.

[0026] In step 1), the calcination at this temperature can remove water, including adsorbed water and crystal water of NiO, load NiO on SiO2, prevent sintering, and maintain high reaction activity of NiO, thereby being more easily reduced by hydrogen.

[0027] Preferably, in step 2), the mass ratio of Al2O3 in the alumina loaded with NiO and NiO / SiO2 is 60-70%, the mass ratio of NiO is 20-30%, and the mass ratio of SiO2 is 10-20%.

[0028] If the content of NiO is too high, the Ni particles are prone to mutual aggregation, resulting in too large Ni particle size in the catalyst, affecting the catalytic effect; if the content of NiO is too low, the content of Ni particles in the catalyst is too low, affecting the catalytic activity. If the content of SiO2 is too high, the content of relatively large particle size Ni-Si / SiO2 in the catalyst is too high, which is not conducive to the diffusion of the reaction gas in the catalyst, and at the same time affects the uniform distribution of Ni; if the content of SiO2 is too low, the content of Ni-Si / SiO2 in the catalyst is too low, which cannot effectively play the effect of strong interaction.

[0029] Preferably, in step 2), the drying temperature is 100-120℃, and the time is 10-15h.

[0030] Preferably, in step 2), the calcination temperature is 500-600℃, and the time is 4-6h.

[0031] In step 2), the calcination condition can further remove water, at the same time, decompose Ni(NO3)2 to generate NiO, and maintain the reaction activity of NiO, and does not change the original performance of NiO on the loaded SiO2.

[0032] Preferably, in step 3), the alumina loaded with NiO and NiO / SiO2 is first reduced and treated under a hydrogen atmosphere at a slow temperature rise to 350-380℃ for 4-6h, then silicified and treated under a SiH4 / H2 atmosphere with a volume ratio of SiH4 to H2 of 5-15% for 20-30min, and then cooled to room temperature under a hydrogen atmosphere.

[0033] In a third aspect, the application provides an application of the above-mentioned high-selectivity reforming oil hydrogenation catalyst in reforming oil hydrogenation catalytic deolefination.

[0034] Compared with the prior art, the application has the following technical effects:

[0035] (1) The catalyst of the application is loaded with single-crystal Ni particles, Ni-Si and Ni-Si / SiO2 on the carrier, wherein the Ni-Si and Ni-Si / SiO2 play a barrier role on the single-crystal Ni particles, can improve the catalytic activity and olefin hydrogenation selectivity of the catalyst in the process of reforming oil hydrogenation catalytic deolefination, and reduce the carbon deposition to prolong the service life.

[0036] (2) In the catalyst of the application, part of the Ni is silicified into a Ni-Si compound, which changes the geometric structure and electronic structure of the Ni; at the same time, the Ni-Si has a strong interaction with the SiO2, thereby improving the catalytic activity and chemical stability of the catalyst.

[0037] (3) The catalyst of the present application does not use noble metal elements, thus having the advantage of low cost and being suitable for industrial promotion. DETAILED DESCRIPTION

[0038] The present application is further described below in conjunction with examples.

[0039] A high-selectivity reforming-generating oil hydrogenation catalyst, comprising an alumina carrier and monocrystal Ni particles, Ni-Si and Ni-Si / SiO2 supported on the alumina carrier; the Ni-Si and Ni-Si / SiO2 are distributed between the monocrystal Nis.

[0040] Preferably, the specific surface area of the catalyst is 150-260 m 2 / g, the pore volume is 0.3-0.7 cm 3 / g, and the pores with a pore size of 5-10 nm account for 60-80% of the total pore volume of the catalyst.

[0041] The preparation method of the above-mentioned high-selectivity reforming-generating oil hydrogenation catalyst comprises the following steps:

[0042] 1) SiO2 powder and modified nickel solution (prepared by mixing ethylene glycol and nickel acetylacetone in a mass ratio of 20-30:1) are mixed, the pH is adjusted to be alkaline (preferably 9-10), and the reaction is heated (preferably at 110-130℃ for 1-2h); after cooling, filtering, washing to neutral, calcining (preferably at 500-600℃ for 2-3h), and crushing, a NiO / SiO2 composite powder is obtained (the mass ratio of NiO is preferably 20-30%).

[0043] 2) The Al2O3 powder and the NiO / SiO2 composite powder are uniformly mixed, and an aqueous solution of Ni(NO3)2 is added and stirred into a paste; after drying (preferably at 100-120℃ for 10-15h), grinding, shaping, and calcining (preferably at 500-600℃ for 4-6h), an alumina loaded with NiO / SiO2 is obtained (the mass ratio of Al2O3 is preferably 60-70%, the mass ratio of NiO is preferably 20-30%, and the mass ratio of SiO2 is preferably 10-20%).

[0044] 3) The alumina loaded with NiO / SiO2 is first reduced at 350-380℃ for 4-6h in a hydrogen atmosphere, then silicified for 20-30min in a SiH4 / H2 atmosphere with a volume ratio of 5-15%, and then reduced and cooled in a hydrogen atmosphere to obtain alumina loaded with monocrystal Ni particles and Ni-Si / SiO2, i.e. a reforming-generating oil hydrogenation catalyst.

[0045] Example 1

[0046] 1) Dissolve nickel acetylacetonate in ethylene glycol at a mass ratio of 1:25 to obtain a modified nickel solution, then add white carbon black powder to the modified nickel solution at a mass ratio of 1:26 under stirring, slowly add a 10% mass ratio concentration sodium carbonate aqueous solution under continuous stirring until the pH value is 9.5, then heat the obtained mixture to 120°C, react for 1.5 h, cool, filter, wash until neutral after the reaction is completed, then heat the obtained solid to 550°C, calcine for 2.5 h, and grind to obtain a NiO / SiO2 composite powder (the mass ratio of NiO is 25.3%).

[0047] 2) Mix Al2O3 dry glue powder and the NiO / SiO2 composite powder obtained in step 1) at a mass ratio of 3:1:6, then add a 40 wt% Ni(NO3)2 aqueous solution to form a lake shape under stirring, dry at 110°C for 12 h, grind, press into a tablet, then calcine the obtained tablet at 550°C for 5 h to obtain a composition (the mass ratio of Al2O3 is 60.2%, the mass ratio of NiO is 25.5%, and the mass ratio of SiO2 is 14.3%).

[0048] 3) Slowly heat the composition obtained in step 2) to 360°C under a H2 atmosphere, reduce for 5 h, then continue to pass a 10% volume ratio SiH4 / H2 atmosphere to silicify for 25 min, then continue to cool to room temperature under a H2 atmosphere to obtain a reforming oil hydrogenation catalyst.

[0049] Example 2

[0050] 1) Dissolve nickel acetylacetonate in ethylene glycol at a mass ratio of 1:30 to obtain a modified nickel solution, then add white carbon black powder to the modified nickel solution at a mass ratio of 1:22.5 under stirring, slowly add a 10% mass ratio concentration sodium carbonate aqueous solution under continuous stirring until the pH value is 9, then heat the obtained mixture to 110°C, react for 1 h, cool, filter, wash until neutral after the reaction is completed, then heat the obtained solid to 500°C, calcine for 2 h, and grind to obtain a NiO / SiO2 composite powder (the mass ratio of NiO is 20.4%).

[0051] 2) Mix Al2O3 dry glue powder and the NiO / SiO2 composite powder obtained in step 1) at a mass ratio of 5.6:1:8.4, then add a 40 wt% Ni(NO3)2 aqueous solution to form a lake shape under stirring, dry at 100°C for 10 h, grind, press into a tablet, then calcine the obtained tablet at 500°C for 4 h to obtain a composition (the mass ratio of Al2O3 is 69.7%, the mass ratio of NiO is 20.2%, and the mass ratio of SiO2 is 10.1%).

[0052] 3) The composition prepared in step 2) is slowly heated to 350°C under H2 atmosphere for 5h, then continued to be siliconized under SiH4 / H2 atmosphere with volume ratio of 10% for 20min, and then continued to be cooled to normal temperature under H2 atmosphere to prepare the reforming oil hydrogenation catalyst.

[0053] Example 3

[0054] 1) Acetylacetone nickel is dissolved in ethylene glycol with mass ratio of 1:20 to obtain a modified nickel solution, and then white carbon black powder is added into the modified nickel solution with mass ratio of 1:27 under stirring, and then 10% mass concentration sodium carbonate aqueous solution is slowly added into the mixture under continuous stirring until the pH value is 10, and then the obtained mixture is heated to 130°C for 2h, and then the reaction is completed, and then the obtained solid is cooled, filtered, washed until neutral, and then the obtained solid is heated to 600°C for calcination for 3h and then ground to obtain NiO / SiO2 composite powder (mass ratio of NiO is 29.8%).

[0055] 2) Al2O3 dry glue powder is mixed with the NiO / SiO2 composite powder prepared in step 1) with mass ratio of 2.1:1:2.4, and then 40wt% Ni(NO3)2 aqueous solution is added into the mixture under stirring to form a lake, and then the obtained mixture is dried at 120°C for 15h, and then the obtained mixture is ground and tablet-shaped, and then the obtained tablet-shaped material is calcined at 600°C for 6h to obtain a composition (mass ratio of Al2O3 is 60.6%, mass ratio of NiO is 20.6%, and mass ratio of SiO2 is 18.8%).

[0056] 3) The composition prepared in step 2) is slowly heated to 380°C under H2 atmosphere for 6h, and then continued to be siliconized under SiH4 / H2 atmosphere with volume ratio of 10% for 30min, and then continued to be cooled to normal temperature under H2 atmosphere to prepare the reforming oil hydrogenation catalyst.

[0057] Comparative Example 1

[0058] Compared with Example 1, the difference is that step 1) in Example 1 is omitted, that is, the prepared reforming oil hydrogenation catalyst does not contain Ni-Si / SiO2, that is, Al2O3 is used as the carrier, and Ni and Ni-Si are used as the active components.

[0059] 1) Al2O3 dry glue powder is added into 40wt% Ni(NO3)2 aqueous solution with mass ratio of 7:18 under stirring to form a lake, and then the obtained mixture is dried at 110°C for 12h, and then the obtained mixture is ground and tablet-shaped, and then the obtained tablet-shaped material is calcined at 550°C for 5h to obtain a composition (mass ratio of Al2O3 is 70.2%, and mass ratio of NiO is 29.8%).

[0060] 2) The composition prepared in step 2) is slowly heated to 360°C under H2 atmosphere for reduction for 5h, then continues to be fed with SiH4 / H2 atmosphere with volume ratio of 10% for silication for 25min, and then continues to be cooled to normal temperature under H2 atmosphere to prepare the reforming oil hydrogenation catalyst.

[0061] Comparative Example 2

[0062] Compared with Example 1, the difference is that no Ni(NO3)2 aqueous solution is added in step 2), but pure water is used instead, so that the prepared reforming oil hydrogenation catalyst contains too low Ni and Ni-Si active ingredients.

[0063] 1) Dissolve nickel acetylacetonate in ethylene glycol with mass ratio of 1:25 to obtain a modified nickel solution, then add white carbon black powder to the modified nickel solution with mass ratio of 1:26 under stirring, slowly add 10% mass concentration sodium carbonate aqueous solution until the pH value is 9.5 under continuous stirring, then heat the obtained mixture to 120°C, react for 1.5h, cool, filter, wash until neutral after the reaction is completed, then heat the obtained solid to 550°C for calcination for 2.5h and grind to obtain NiO / SiO2 composite powder (the mass ratio of NiO is 25.3%).

[0064] 2) Mix Al2O3 dry glue powder with the NiO / SiO2 composite powder prepared in step 1) in sequence with mass ratio of 3:1:6, then add pure water to stir into a lake shape, dry at 110°C for 12h, grind, press and form into a tablet, then calcine the obtained formed material at 550°C for 5h to obtain a composition (the mass ratio of Al2O3 is 75.0%, the mass ratio of NiO is 6.2%, and the mass ratio of SiO2 is 18.8%).

[0065] 3) The composition prepared in step 2) is slowly heated to 360°C under H2 atmosphere for reduction for 5h, then continues to be fed with SiH4 / H2 atmosphere with volume ratio of 10% for silication for 25min, and then continues to be cooled to normal temperature under H2 atmosphere to prepare the reforming oil hydrogenation catalyst.

[0066] Comparative Example 3

[0067] Compared with Example 1, the difference is only that the calcination temperature in step 1) and step 2) is too low:

[0068] 1) Dissolve nickel acetylacetonate in ethylene glycol at a mass ratio of 1:25 to obtain a modified nickel solution, then add white carbon black powder to the modified nickel solution at a mass ratio of 1:26 under stirring, slowly add a 10% mass ratio concentration sodium carbonate aqueous solution under continuous stirring until the pH value is 9.5, then heat the obtained mixture to 120°C, react for 1.5 h, cool, filter, wash until neutral after the reaction is completed, then heat the obtained solid to 400°C, calcine for 2.5 h, and grind to obtain a NiO / SiO2 composite powder (the mass ratio of NiO is 25.1%).

[0069] 2) Mix Al2O3 dry glue powder with the NiO / SiO2 composite powder obtained in step 1) at a mass ratio of 3:1:6, then add a 40 wt% Ni(NO3)2 aqueous solution to form a lake under stirring, dry at 110°C for 12 h, grind, press into a tablet, then calcine the obtained molding at 400°C for 5 h to obtain a composition (the mass ratio of Al2O3 is 60.3%, the mass ratio of NiO is 25.2%, and the mass ratio of SiO2 is 14.5%).

[0070] 3) Slowly heat the composition obtained in step 2) to 360°C under a H2 atmosphere, reduce for 5 h, then continue to pass a 10% volume ratio SiH4 / H2 atmosphere to silicify for 25 min, then continue to cool to room temperature under a H2 atmosphere to obtain a reforming oil hydrogenation catalyst.

[0071] Comparative Example 4

[0072] Compared with Example 1, the only difference is that the calcination temperature in steps 1) and 2) is too high:

[0073] 1) Dissolve nickel acetylacetonate in ethylene glycol at a mass ratio of 1:25 to obtain a modified nickel solution, then add white carbon black powder to the modified nickel solution at a mass ratio of 1:26 under stirring, slowly add a 10% mass ratio concentration sodium carbonate aqueous solution under continuous stirring until the pH value is 9.5, then heat the obtained mixture to 120°C, react for 1.5 h, cool, filter, wash until neutral after the reaction is completed, then heat the obtained solid to 900°C, calcine for 2.5 h, and grind to obtain a NiO / SiO2 composite powder (the mass ratio of NiO is 25.3%).

[0074] 2) The Al2O3 dry glue powder and the NiO / SiO2 composite powder prepared in step 1) are mixed in the order of 3:1:6 by mass ratio, and then a 40wt% Ni(NO3)2 aqueous solution is added to form a lake shape after stirring, and then dried at 110℃ for 12h, ground, and then pressed into a tablet, and then the obtained molding is calcined at 900℃ for 5h to obtain a composition (the mass ratio of Al2O3 is 60.2%, the mass ratio of NiO is 25.2%, and the mass ratio of SiO2 is 14.6%).

[0075] 3) The composition prepared in step 2) is slowly heated to 360℃ under H2 atmosphere for 5h, and then continued to be silylated for 25min under a SiH4 / H2 atmosphere with a volume ratio of 10%, and then continued to be cooled to room temperature under H2 atmosphere to obtain a reforming oil hydrogenation catalyst.

[0076] Performance test

[0077] The hydrogenation catalysts prepared in each example and the comparative example are respectively used for reforming oil deolefin test, and the specific method is as follows: the hydrogenation catalyst is loaded in a hydrogenation reactor, and first pretreated by hydrogen, and the reduction temperature is increased from room temperature to 400℃ at a rate of 2℃ / min under a pressure of 1.0MPa, and then decreased to the reaction temperature after 4h of treatment. The reforming oil is transported from the reforming device to a de-pentane column (the top pressure is 0.95MPa, the top temperature is 87℃, the bottom temperature is 215℃, the tray temperature is 160℃, and the reflux ratio is 0.2), and after treatment by the de-pentane column, the de-pentane column bottom oil (main properties are shown in Table 1) and hydrogen are respectively transported to the hydrogenation reactor; the experimental conditions are as follows: the reaction temperature is 130℃, the reaction pressure is 1.1MPa, the volume space velocity is 10h -1 , and the hydrogen / oil ratio is 23:1. After 6h of stabilization, the sample is discharged, and the 2h cumulative sample is taken.

[0078] Table 1

[0079]

[0080] The pore structure parameters of the catalyst are analyzed by using a Tristar 3020 adsorber of the American Micromertics company, and the determination conditions are as follows: adsorption temperature 350℃, vacuum environment 0.95×10 -6 ~0.12×10 -5 MPa, and adsorption time 12h. The bromine index of the product after catalytic hydrogenation of the reforming oil is determined according to the national standard GB / T1815-2019, and the AK-BR-1A type bromine value bromine index tester of Dalian Ausi Analysis Instrument Co., Ltd. is used, and the unit of the sample bromine index is 100g Br / mg.

[0081] Firstly, the Agilent 7890A-PONA type gas chromatograph of Agilent Company of the United States is used to determine the components such as aromatic hydrocarbons of the reforming product oil before and after catalytic hydrogenation, and then the formula is used to calculate the aromatic hydrocarbon damage rate of the reforming product oil after catalytic hydrogenation. The determination conditions are as follows: the PONA column diameter is 50 mm, the carrier gas is nitrogen, the column oven initial temperature is 30℃, the temperature is raised to 150℃ at a rate of 5℃ / min, the final temperature is kept for 2 min, the capillary column flow is 2.5 mL / min, the injection port split ratio is 50:1. The FID detector temperature is 220℃, the hydrogen flow is 40 mL / min, the air flow is 380 mL / min, the gas path carrier gas connected with the FID for hydrocarbon analysis is nitrogen, the capillary column flow is 3 mL / min, and the injection port split ratio is 50:1. The TCD detector temperature is 150℃, the gas path carrier gas connected with the TCD for inorganic gas analysis is helium, and the packed column flow is 20 mL / min. The aromatic hydrocarbon loss rate (x) calculation formula is x=(1-w1 / w2)×100%, wherein w1 is the mass fraction of aromatic hydrocarbons in the reforming product oil before catalytic hydrogenation, %; and w2 is the mass fraction of aromatic hydrocarbons in the reforming product oil after catalytic hydrogenation, %.

[0082] Table 2

[0083]

[0084]

[0085] From Table 2, it can be seen that the catalysts prepared in Examples 1-3 have low bromine index and aromatic hydrocarbon loss rate when applied in the reforming product oil hydrogenation process, which indicates that the catalysts prepared by the present application have high olefin hydrogenation effect, but the aromatic hydrocarbon hydrogenation effect is not obvious, thereby greatly improving the selectivity of the reforming product oil hydrogenation.

[0086] The catalyst prepared in Comparative Example 1 does not contain Ni-Si / SiO2 component, only contains Ni and Ni-Si active components on the Al2O3 carrier, and has no strong interaction of Ni-Si / SiO2, which greatly reduces the performance such as hydrogen adsorption of the catalyst, thereby causing the bromine index and aromatic hydrocarbon loss rate to be high in the reforming product oil hydrogenation process.

[0087] The catalyst prepared in Comparative Example 2 contains too low Ni and Ni-Si active components, which fails to fully exert the catalytic hydrogenation activity of the metal Ni, resulting in high bromine index and aromatic hydrocarbon loss rate in the reforming product oil hydrogenation process.

[0088] The catalyst prepared in Comparative Example 3 has low NiO loading strength due to low calcination temperature, and the pore structure parameters of the final catalyst change greatly, which results in high reaction activity in the hydrogenation process of reformate, high loss rate of aromatic hydrocarbons and poor reaction selectivity; the catalyst prepared in Comparative Example 4 has NiO sintered together due to high calcination temperature, and the active component of the final catalyst is not uniformly distributed, and the pore structure is dense, which results in low reaction activity in the hydrogenation process of reformate and high bromine index.

[0089] The raw materials and equipment used in the present application are common raw materials and equipment in the art unless otherwise specified; the methods used in the present application are conventional methods in the art unless otherwise specified.

[0090] The above description is only a preferred embodiment of the present application, and does not limit the present application in any way, and any simple modification, change and equivalent transformation of the above embodiment according to the technical essence of the present application still belongs to the protection scope of the technical solution of the present application.

Claims

1. The application of a highly selective reforming product oil hydrotreating catalyst in the catalytic deolefination of reforming product oil, characterized in that: The highly selective reforming product oil hydrogenation catalyst includes an alumina support and single-crystal Ni particles, Ni-Si, and Ni-Si / SiO2 supported on the alumina support; the Ni-Si and Ni-Si / SiO2 are spaced apart between the single-crystal Ni particles.

2. The application according to claim 1, characterized in that: Specific surface area is 150-260 m² 2 / g, pore volume 0.3-0.7cm³ 3 / g, of which pores with a diameter of 5-10nm account for 40-50% of the total pore volume of the catalyst.

3. A method for preparing a highly selective reforming product oil hydrogenation catalyst, characterized in that... Includes the following steps: 1) SiO2 powder and modified nickel solution are mixed, pH is adjusted to alkaline, heated to react, and after post-treatment, calcination and pulverization, NiO / SiO2 composite powder is obtained; 2) Alumina powder and NiO / SiO2 composite powder are mixed evenly, and Ni(NO3)2 aqueous solution is added and stirred into a paste. After drying, grinding, pressing into tablets, and calcining, alumina loaded with NiO and NiO / SiO2 is obtained. 3) First, the alumina loaded with NiO and NiO / SiO2 is reduced in a reducing atmosphere, then silanized in an atmosphere containing SiH4 / H2, and then reduced and cooled in a reducing atmosphere to obtain alumina loaded with single-crystal Ni particles, Ni-Si and Ni-Si / SiO2, which is the reforming product oil hydrogenation catalyst.

4. The preparation method according to claim 3, characterized in that: In step 1), the mass percentage of NiO in the NiO / SiO2 composite powder is 20-30%.

5. The preparation method according to claim 3 or 4, characterized in that: In step 1), the modified nickel solution is an ethylene glycol solution of nickel acetylacetonate, and the mass ratio of ethylene glycol to nickel acetylacetonate is 20-30:

1.

6. The preparation method according to claim 3 or 4, characterized in that: In step 1), The alkaline pH is 9-10; The heating reaction is carried out at a temperature of 110-130℃ for 1-2 hours. The post-treatment involves cooling, filtering, and washing until neutral. The calcination temperature is 500-600℃, and the time is 2-3 hours.

7. The preparation method according to claim 3, characterized in that: In step 2), the mass percentage of Al2O3 in the alumina loaded with NiO and NiO / SiO2 is 60-70%, the mass percentage of NiO is 20-30%, and the mass percentage of SiO2 is 10-20%.

8. The preparation method according to claim 3 or 7, characterized in that: In step 2), The drying temperature is 100-120℃, and the time is 10-15 hours; The calcination temperature is 500-600℃, and the time is 4-6 hours.

9. The preparation method according to claim 3, characterized in that: In step 3), the alumina loaded with NiO and NiO / SiO2 is first slowly heated to 350-380℃ for 4-6 hours under a hydrogen atmosphere for reduction treatment, then siliconized for 20-30 minutes under a SiH4 / H2 atmosphere with a SiH4 / H2 volume ratio of 5-15%, and then cooled to room temperature under a hydrogen atmosphere.

10. The application of the highly selective reformate hydrotreating catalyst obtained by the preparation method according to any one of claims 3-9 in the catalytic deolefination of reformate hydrotreating.

Images