A multi-stage composite pore-expanding catalyst for the hydrodearsenic removal of oil and its preparation method
By employing multi-stage composite pore expansion and pre-dispersion impregnation technologies, the problem of reduced arsenic poisoning sites in existing catalysts after pore expansion has been solved, achieving efficient arsenic removal and long-term stability, and reducing refinery operating costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- PETROCHINA CO LTD
- Filing Date
- 2022-12-23
- Publication Date
- 2026-07-17
AI Technical Summary
Existing hydroarsenic removal catalysts have reduced arsenic poisoning sites on the catalyst surface after pore-expansion treatment, which affects the catalyst's rapid reaction characteristics and the dispersion of active metals, resulting in poor arsenic removal performance and increased investment costs for refineries.
By employing a multi-stage composite pore-expansion method combined with pre-dispersion impregnation technology, and through multi-stage treatment with organic complexing agents and pore-expansion aids, the active metal is ensured to be uniformly dispersed in the pores, thereby increasing the number and utilization rate of arsenic poisoning sites and enhancing the catalyst's rapid arsenic removal performance.
This improved the arsenic removal efficiency of the catalyst under high space velocity conditions, extended the catalyst's service life, met the requirements for long-term stable operation, and reduced the refinery's investment costs.
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Abstract
Description
Technical Field
[0001] This invention relates to a catalyst, and more particularly to a hydrodearsenic removal catalyst used in petroleum processing and its preparation method. Background Technology
[0002] Hydrogenation technology is one of the main methods for improving the quality of oil products in my country. The refining industry routinely uses hydrogenation to reduce the content of impurities such as sulfur, nitrogen, and aromatics in oil products to improve their quality. Arsenic compounds in the feedstock are poisons during the hydrogenation process, especially in reforming units using precious metal catalysts. Even a small amount of arsenic compounds can cause permanent poisoning and deactivation of the catalyst, shortening the long-term operation of the unit and resulting in economic losses for the refinery. Therefore, arsenic compounds need to be removed beforehand to ensure the stable operation of subsequent units. Different production stages have different requirements for the arsenic content of the feedstock. In reforming and other units using precious metal catalysts, the arsenic content of the feedstock needs to be stable at <1 ppb over a long period. This places higher demands on the high arsenic removal activity and long-term stability of the arsenic removal agent.
[0003] Common methods for removing arsenic from oil products include adsorption, oxidation, and hydrotreating. Hydrotreating offers high arsenic capacity, excellent removal efficiency, and long operating cycles, making it more suitable for production conditions with high arsenic content in feedstocks, low arsenic content requirements in products, and long operating cycles. Unlike desulfurization, trace amounts of organic arsenic compounds readily combine with the d orbitals of Group VIII metals (such as Ni) on the surface of conventional hydrotreating catalysts, forming coordinate bonds. As temperature increases, a large number of arsenic atoms migrate from the surface to the catalyst interior, forming arsenide alloys. Therefore, hydrotreating catalysts need to provide more arsenic poisoning sites (generally manifested by arsenic capacity) and a suitable diffusion environment to meet the demands of long-term operation. Hydrotreating differs from hydrodesulfurization; it permanently sacrifices a large number of arsenic poisoning sites, rendering previously utilized sites unusable. Therefore, improving the effective utilization rate of these poisoning sites is crucial.
[0004] Currently, to address the diffusion of large arsenic molecules in arsenic removal catalysts, pore-expanding treatment is typically performed. While this facilitates the entry of large arsenic molecules into the pores, it inevitably reduces the number of arsenic poisoning sites on the catalyst surface. Furthermore, small arsenic molecules in the feedstock do not require large pores to facilitate their flow. Arsenic removal processes generally employ high space velocities, thus requiring catalysts with rapid arsenic removal performance. Reducing surface arsenic poisoning sites diminishes the catalyst's fast reaction characteristics. Additionally, the impregnation process cannot guarantee sufficient entry of the active metal into the pores, nor can it guarantee the dispersion of the active metal within the pores, resulting in wasted arsenic poisoning sites.
[0005] Patent CN 1043151C discloses a single-nickel catalyst prepared on a macroporous alumina support with a dual-channel distribution. It requires reduction under H2 and N2 atmospheres during use and can reduce arsenic content to below 5 ppb. CN 102140C relates to an arsenic removal catalyst for hydrocarbons, with a single-nickel system as the active center and a macroporous alumina support. It requires at least 50% of the nickel-hydrogen gas to be reduced before use and can also reduce arsenic content to below 5 ppb. However, both of these existing technologies use reduction as a pretreatment method for the catalyst. Currently, most mainstream catalysts in conventional oil refining hydrotreating processes are in a sulfide state. Reduction activation increases start-up complexity. Furthermore, although this patent uses macroporous alumina, it does not consider the dispersion of active metals within the pores, affecting the utilization rate of arsenic poisoning sites.
[0006] Patent CN 108246242B proposes a catalytic gasoline hydrotreating catalyst and its application. This technology utilizes hydrothermal modification of the TiO2-Al2O3 composite support and employs a single-nickel system to prepare the hydrotreating catalyst. The catalyst exhibits good arsenic removal selectivity, achieving over 99% selectivity when processing feedstocks with an arsenic content of approximately 200 ppb. Patent CN108246302B proposes a catalytic gasoline hydrotreating catalyst and its application. This technology also employs hydrothermal modification of the TiO2-Al2O3 composite support and uses a bimetallic arsenic removal catalyst, which can reduce the arsenic content of feedstocks from 200 ppb to below 20 ppb. Its arsenic capacity is improved compared to the single-nickel system. However, in the catalyst preparation methods of the above two inventions, the average pore size of the catalyst increases after support modification. Although this is beneficial for the diffusion of large molecular arsenides, it affects the fast reaction characteristics of the catalyst in arsenic removal. Furthermore, this patent does not address the issue of metal dispersion in the pore channels after pore expansion.
[0007] Patent CN 106833731B proposes a catalyst for the hydrodearsenic removal of naphtha and its application method. The catalyst support is prepared by alternating titration with non-constant pH, resulting in a zinc oxide layered structure containing zinc aluminum spinel. The preparation process is complex and has high industrial production costs, making it difficult to achieve in actual production. At the same time, it does not address the issue of dispersing and utilizing active metals within the pores.
[0008] Patent CN 100388980C proposes a pseudoboehmite composition containing an organic pore expander. By adding an organic pore expander to the pseudoboehmite, macroporous alumina can be obtained after calcination. However, the catalyst preparation method involved in this invention will also affect the fast reaction characteristics of the catalyst for arsenic removal, and it does not address the issues of dispersion and utilization of active metals within the pores.
[0009] Patent CN 102284295B proposes a method for preparing a hydrogenation catalyst impregnation solution and a method for preparing the catalyst. This invention uses water-soluble organic additives to reduce the surface tension of the impregnation solution, without calcination, and reduces the aggregation of metal particles, thereby effectively improving the hydrogenation activity of the hydrogenation catalyst for heavy aromatics. However, this method does not address the utilization of metals in the pores, nor does it address the diffusion of macromolecular raw materials in the catalyst pores.
[0010] Patent CN107812525A discloses a hydrogenation catalyst composition comprising hydrogenation catalyst I and hydrogenation catalyst II. The hydrogenation catalyst I, by volume and based on the hydrogenation catalyst composition, comprises 5-95%. Hydrogenation catalyst I comprises a support, a hydrogenation-active metal element, and a non-metallic auxiliary element, wherein the hydrogenation-active metal element contains Group VIB and Group VIII metal elements. The preparation method of hydrogenation catalyst I includes: subjecting a support loaded with a compound containing a hydrogenation-active metal element, a first organic complexing agent, and a non-metallic auxiliary element to a first drying and calcination to obtain a semi-finished catalyst; wherein, by dry basis and based on the dry weight of the semi-finished catalyst, the carbon content of the semi-finished catalyst is 0.01-0.5% by weight; loading a second organic complexing agent onto the semi-finished catalyst, and subjecting it to a second drying without calcination to obtain hydrogenation catalyst I. This technology is applied in the field of desulfurization and denitrification. The active metal and complex components are added together to the impregnation solution before the impregnation of the carrier. The poor dispersion of the active metal will cause the active metal to stack. In the field of hydrodearsenic removal, the stacking of active metal will cause the loss of arsenic poisoning sites. Therefore, the dispersion of the active metal needs to be further improved. In addition, the preparation method of the hydrogenation catalyst involved in this technology does not involve the utilization of metal in the pores. Summary of the Invention
[0011] To address the aforementioned problems, this invention provides a multi-stage composite pore-expanding catalyst for hydroarsenic removal from oil products and its preparation method. During the catalyst impregnation process, a multi-stage pore-expanding approach ensures the flowability of large arsenic molecules in the catalyst while maintaining selectivity in reactant molecular size and morphology. Simultaneously, it retains more arsenic poisoning sites on the catalyst surface, improving the rapid arsenic removal reaction platform under high space velocities and satisfying the catalyst's stable arsenic removal activity under these conditions. Furthermore, this invention employs a pre-dispersion impregnation method, where a pre-dispersion solution is prepared before being dispersed and complexed with the main active metal. This ensures that the main active metal is fully complexed with the pore-expanding and dispersing components, guaranteeing that the active metal enters the pore channels for high dispersion loading during pore expansion. This increases the number of arsenic poisoning sites on the catalyst while ensuring full utilization of the active metal within the pores, thereby improving the catalyst's arsenic capacity and reducing refinery investment costs.
[0012] To achieve the above objectives, the present invention provides a method for preparing a multi-stage composite pore-expanding catalyst for the hydrodearsenic removal of oil products, the method comprising the following steps:
[0013] (1) Organic complexing agent I, pore-expanding agent II, pore-expanding agent III, active component IV containing group VIB metal and deionized water are formulated into stable dispersion impregnation component A-1;
[0014] (2) Dissolve the component containing Group VIII metal in the stable dispersion impregnation component A-1 to form a stable complex impregnation solution A-2;
[0015] (3) The porous support Z was impregnated with stable complex impregnation solution A-2, and then dried and calcined to obtain catalyst C1;
[0016] (4) Dissolve organic auxiliary agent V and activator VI in deionized water, impregnate catalyst C1, and after drying and calcination, obtain the final hydrogen arsenic removal catalyst C2;
[0017] Wherein, the Group VIB metal is at least one of molybdenum and tungsten;
[0018] The molecular weight of the pore-expanding agent III in step (1) is smaller than that of the pore-expanding agent II.
[0019] Preferably, in step (1), the organic complexing agent I is ammonia or a hydroxy acid compound, including one of ethylene glycol, glyceric acid, malic acid, citric acid, tartaric acid, gluconic acid, acetic acid, oxalic acid, malonic acid, trichloroacetic acid, and monochloroacetic acid, more preferably ammonia or citric acid.
[0020] Preferably, in step (1), the pore-expanding agent II and pore-expanding agent III are at least one of glycerol, propylene glycol, 1,4-butanediol, pentaerythritol, ethylene glycol, polyethylene glycol, diethylene glycol, polyvinyl alcohol, sodium stearate, carboxymethyl cellulose, and soluble starch, more preferably at least one of glycerol, ethylene glycol, polyethylene glycol, sodium carboxymethyl cellulose, and soluble starch.
[0021] Preferably, in step (1), the content of the pore-expanding agent II accounts for 0.5 to 20 wt% of the porous carrier Z, more preferably 1 to 16 wt%; and the content of the pore-expanding agent III accounts for 0.5 to 20 wt% of the porous carrier Z, more preferably 1 to 16 wt%.
[0022] Preferably, the auxiliary active component IV containing Group VIB metal is a soluble salt, soluble acid solution or oxide of molybdenum or tungsten; more preferably, the auxiliary active component IV containing Group VIB metal is molybdate or molybdenum trioxide.
[0023] Preferably, the component containing a Group VIII metal is a nickel salt, including at least one of nickel nitrate, nickel acetate, nickel sulfate, and nickel basic carbonate, more preferably nickel nitrate or nickel basic carbonate.
[0024] Preferably, the hydroarsenic removal catalyst C2 contains 5-24 wt% NiO, 0.5-24 wt% MoO3 and / or WO3, and 52-94.5 wt% support; more preferably, it contains 6-21 wt% NiO, 1-15 wt% MoO3 or WO3, and 64-93 wt% support.
[0025] Preferably, the porous carrier Z is one or more composite carriers of alumina, titanium dioxide, silicon dioxide, and magnesium oxide, and more preferably alumina.
[0026] Preferably, in step (1), the temperature during the preparation of the stable dispersion impregnation component A-1 is 10 to 100°C, the temperature does not exceed the boiling point of the pore-expanding agent II and the pore-expanding agent III, and the mixing time is 10 min to 120 min.
[0027] Preferably, in step (2), the temperature during the preparation of the stable dispersion impregnation component A-2 is 10 to 100°C, the temperature does not exceed the boiling point of the pore-expanding agent II and the pore-expanding agent III, and the mixing time is 10 min to 120 min.
[0028] Preferably, in step (4), the organic additive V is an alcohol, including at least one of ethanol, glycerol, ethylene glycol, and polyethylene glycol.
[0029] Preferably, in step (4), the molecular weight of the alcohol in the organic auxiliary agent V is smaller than the molecular weight of the pore-expanding auxiliary agent III.
[0030] Preferably, in step (4), the amount of organic auxiliary agent V added is 0.5 to 16 wt% of the mass of catalyst C1, more preferably 1 to 10 wt%.
[0031] Preferably, in step (4), the activating agent VI is at least one of phosphoric acid, phosphate and boric acid.
[0032] Preferably, in step (4), the amount of activator VI added is 1 to 10 wt% of the mass of catalyst C1, more preferably 3 to 7 wt%.
[0033] Preferably, in step (3) or step (4), after impregnation, the mixture needs to stand for 1 to 7 hours before drying and roasting, more preferably 1 to 6 hours.
[0034] Preferably, in step (3) or step (4), the drying temperature is 50-150°C and the drying time is 3-6 hours, more preferably the drying temperature is 50-120°C; the calcination temperature is 300°C-600°C and the calcination time is 3-6 hours.
[0035] Preferably, in step (3) or step (4), the impregnation process is saturated impregnation or supersaturated impregnation, more preferably saturated impregnation.
[0036] Preferably, the hydrodearsenic removal catalyst C2 is used in a sulfided form during the dearsenic removal process in oil processing.
[0037] The present invention also provides a multi-stage composite pore-expanding oil hydrodearsenic removal catalyst, which is obtained by the above preparation method.
[0038] Compared with the prior art, the present invention has at least the following advantages:
[0039] (1) The catalyst preparation process adopts a multi-stage pore expansion method to ensure the flowability of macromolecular arsenic in the catalyst while taking into account the selectivity of reactant molecular size and morphology. At the same time, it retains more arsenic poisoning sites on the catalyst surface, improves the rapid arsenic removal reaction environment under high space velocity, and meets the stable arsenic removal activity of the catalyst under high space velocity conditions.
[0040] (2) In a single impregnation, a pre-dispersion impregnation method is adopted, in which the dispersing aid (i.e., organic complexing agent I), pore-expanding aid (II, III) and co-active component IV are uniformly complexed and then complexed with the Group VIII main active metal. This can ensure the uniform dispersion of the pore-expanding aid and co-active component IV with the Group VIII main active metal, improve the dispersion of active metal in the catalyst loading process, and thus increase the number of arsenic poisoning sites.
[0041] (3) Pore-expanding aids II and III are pre-dispersed and then complexed with group VIII active metals. During the calcination process, the pores can be expanded and the active metals can be uniformly loaded. This not only improves the diffusion of macromolecular arsenides into the pores and increases the utilization rate of active sites in the pores, but also improves the dispersion and number of arsenic poisoning sites in the expanded pores.
[0042] (4) By using post-treatment methods, small molecule organic additive V with a molecular weight smaller than that of the two pore-expanding additives II and III is used to disperse the active metal in a secondary manner, and the pore channels are improved by combining it with activation additive VI. This can ensure that the secondary activation impregnation solution enters the pore channels, prevent metal agglomeration caused by heating during the calcination process after metal impregnation, and disperse the active metal on the surface and in the pores in a secondary manner, thereby further improving the dispersion and effective utilization rate of arsenic poisoning sites on the surface and in the pores, and increasing the arsenic capacity.
[0043] (5) Increasing the arsenic capacity can improve the service life of the catalyst, ensure long-term ultra-deep stable arsenic removal, ensure the stable operation of long-term refinery units, and save investment costs. Detailed Implementation
[0044] The technical solutions of the present invention are further described below through embodiments, but the technical solutions of the present invention are not limited to the following embodiments.
[0045] The catalyst supports used in the examples and comparative examples can be obtained by the following preparation methods. However, it should be noted that the following preparation methods are only intended to provide a feasible method for preparing the support and are not intended to limit the present invention. The supports and preparation methods of the present invention are not limited thereto:
[0046] 600g of boehmite was mixed with 12g of guar gum powder, and then a solution consisting of 28g of citric acid, 17mL of concentrated nitric acid, and 500g of water was added. D3.0 clover-shaped wet strips were prepared using a conventional laboratory extruder, dried at 120℃, and then calcined at 800℃ for 6 hours to obtain carrier L1. The properties of carrier L1 are shown in Table 1.
[0047] Table 1 Physicochemical properties of the carrier
[0048] project Carrier L1 <![CDATA[Specific surface area, m 2 / g]]> 280 Pore diameter, nm 11.5 Bulk density, g / 100L 65 Water absorption rate, mL / 100g 82
[0049] Example 1
[0050] 0.25 g glycerol, 0.25 g ethylene glycol, and 20.73 g ammonium molybdate were dissolved in 30 mL of 25% ammonia water. The mixture was stirred at 20 °C for 20 min until a homogeneous and clear solution was obtained. Then, 11.73 g nickel acetate was added and the volume was adjusted to 41 mL. The mixture was stirred for 20 min until a homogeneous and clear solution was obtained. 50 g of support L1 was weighed and impregnated with an equal volume. The mixture was allowed to stand for 1 hour, dried at 80 °C for 3 h, and then calcined at 550 °C for 3 h to obtain catalyst C1-1. 0.25 g ethanol and 5 g phosphoric acid were dissolved in deionized water and the volume was adjusted. 50 g of catalyst C1-1 was impregnated with an equal volume. The mixture was dried at 80 °C for 4 h and then calcined at 500 °C for 4 h to obtain the hydroarsenic removal catalyst C2-1.
[0051] Example 2
[0052] 7.5g of polyethylene glycol (4000), 5g of polyethylene glycol (2000), 4.4g of ammonium molybdate, and 3g of citric acid were dissolved in deionized water and mixed at 25°C for 30 min until a homogeneous and clear solution was obtained. Then, 23.2g of nickel nitrate was added and the volume was adjusted to 41mL, and the mixture was mixed for 25 min until a homogeneous and clear solution was obtained. 50g of support L1 was weighed and impregnated with an equal volume. After standing for 6 hours, the mixture was dried at 110°C for 6 hours and then calcined at 500°C for 6 hours to obtain catalyst C1-2. 2.5g of polyethylene glycol (800) and 2.5g of ammonium dihydrogen phosphate were dissolved in deionized water and the volume was adjusted. 50g of catalyst C1-2 was impregnated with an equal volume, dried at 110°C for 6 hours, and then calcined at 500°C for 6 hours to obtain the hydroarsenic removal catalyst C2-2.
[0053] Example 3
[0054] 10g of polyethylene glycol (800), 10g of sodium carboxymethyl cellulose, 0.4g of ammonium molybdate, and 1g of citric acid were dissolved in deionized water and mixed at 25°C for 40 min until a homogeneous and clear solution was obtained. Then, 62g of nickel nitrate was added and the volume was adjusted to 41mL. The mixture was mixed for 30 min until a homogeneous and clear solution was obtained. 50g of support L1 was weighed and impregnated with an equal volume. The mixture was allowed to stand for 4 hours, dried at 120°C for 4 hours, and then calcined at 600°C for 4 hours to obtain catalyst C1-3. 8g of glycerol and 1.5g of boric acid were dissolved in deionized water and the volume was adjusted. 50g of catalyst C1-3 was impregnated with an equal volume, dried at 120°C for 3 hours, and then calcined at 300°C for 3 hours to obtain hydroarsenic removal catalyst C2-3.
[0055] Example 4
[0056] 0.5 g polyethylene glycol (1000), 8 g soluble starch, 0.8 g ammonium molybdate, and 1 g citric acid were dissolved in deionized water and mixed at 50 °C for 50 min until a homogeneous and clear solution was obtained. Then, 52.4 g nickel nitrate was added and the volume was adjusted to 41 mL. The mixture was mixed for 20 min until a homogeneous and clear solution was obtained. 50 g of support L1 was weighed and impregnated with an equal volume. The mixture was allowed to stand for 5 hours, dried at 100 °C for 4 h, and then calcined at 500 °C for 4 h to obtain catalyst C1-4. 5 g ethylene glycol and 0.5 g phosphoric acid were dissolved in deionized water and the volume was adjusted. 50 g of catalyst C1-4 was impregnated with an equal volume, dried at 100 °C for 4 h, and then calcined at 400 °C for 4 h to obtain hydroarsenic removal catalyst C2-4.
[0057] Example 5
[0058] 8g of polyethylene glycol (4000), 0.5g of glycerol, 3g of phosphoric acid, 9.5g of molybdenum oxide, and 2g of citric acid were dissolved in deionized water and mixed at 90℃ for 60 min until a homogeneous and clear solution was obtained. Then, 6.4g of basic nickel carbonate was added, and the mixture was refluxed at 90℃ for 120 min. The volume was adjusted to 41mL, and the mixture was mixed for 10 min until a homogeneous and clear solution was obtained. 50g of support L1 was weighed and impregnated with an equal volume. The mixture was allowed to stand for 6 hours, dried at 100℃ for 5 hours, and then calcined at 500℃ for 5 hours to obtain catalyst C1-5. 0.5g of ethanol and 3.5g of ammonium dihydrogen phosphate were weighed and dissolved in deionized water and adjusted to a final volume. 50g of catalyst C1-5 was impregnated with an equal volume. The mixture was dried at 50℃ for 5 hours and then calcined at 350℃ for 5 hours to obtain hydroarsenic removal catalyst C2-6.
[0059] Comparative Example 1
[0060] Dissolve 0.25g glycerol, 0.25g ethylene glycol, and 20.73g ammonium molybdate in 30mL of 25% ammonia water. Mix at 20℃ for 20min until a homogeneous and clear solution is obtained. Then add 11.73g nickel acetate and bring the volume to 41mL. Mix for 20min until a homogeneous and clear solution is obtained. Weigh 50g of support L1 and impregnate it with an equal volume. Let it stand for 1 hour, dry at 80℃ for 3h, and then calcine at 550℃ for 3h to obtain catalyst D1.
[0061] Comparative Example 2
[0062] 0.25 g glycerol, 0.25 g ethylene glycol, 20.73 g ammonium molybdate, and 11.73 g nickel acetate were dissolved in 30 mL of 25% ammonia water. The mixture was stirred at 20 °C for 20 min until a homogeneous and clear solution was obtained. The solution was then brought to a final volume of 41 mL and stirred for another 20 min until a homogeneous and clear solution was obtained. 50 g of support L1 was weighed and impregnated with this solution in an equal volume. The solution was allowed to stand for 1 hour, dried at 80 °C for 3 h, and then calcined at 550 °C for 3 h to obtain catalyst D2-1. 0.25 g ethanol and 5 g phosphoric acid were dissolved in deionized water and brought to a final volume. 50 g of catalyst D2-1 was impregnated with this solution in an equal volume. The solution was dried at 80 °C for 4 h and then calcined at 500 °C for 4 h to obtain the hydroarsenic removal catalyst D2.
[0063] Comparative Example 3
[0064] 20.73 g of ammonium molybdate was dissolved in 30 mL of 25% ammonia water and mixed at 20 °C for 20 min until a homogeneous and clear solution was obtained. Then, 11.73 g of nickel acetate was added and the volume was adjusted to 41 mL. The mixture was then mixed for 20 min until a homogeneous and clear solution was obtained. 50 g of support L1 was weighed and impregnated with an equal volume. After standing for 1 hour, the solution was dried at 80 °C for 3 h and then calcined at 550 °C for 3 h to obtain catalyst D3-1. 0.25 g of ethanol and 5 g of phosphoric acid were dissolved in deionized water and the solution was adjusted to a final volume. 50 g of catalyst D3-1 was impregnated with this solution, dried at 80 °C for 4 h, and then calcined at 500 °C for 4 h to obtain the hydroarsenic removal catalyst D3.
[0065] Example 6
[0066] This embodiment relates to the catalyst evaluation of Examples 1 to 5 and Comparative Examples 1 to 3.
[0067] The catalyst evaluations for the above embodiments and comparative examples were conducted in a 30mL microreactor evaluation device using wet sulfidation. Carbon disulfide was used as the sulfiding agent at a dosage of 3wt%, and refined naphtha was used as the sulfiding oil. Hydrogen was passed through once. The sulfidation conditions were 230℃ and 320℃ for 8 hours each, with a sulfidation pressure of 2.0 MPa and a hydrogen-to-oil ratio of 300:1. After sulfidation, feedstock oil was introduced. A summary table of feedstock oil properties is shown in Table 2, and a summary table of reaction process parameters and products for each embodiment is shown in Table 3.
[0068] Arsenic content was analyzed using an Agilent ICP-MS 7850. Group composition analysis of the oil was performed using an Agilent PONA chromatographic analyzer.
[0069] The arsenic content experiment used the arsenic-containing raw materials listed in Table 2. The arsenic-containing raw materials were prepared by adding triethylarsenic (25 ppm) to the catalytic gasoline product oil and conducting the experiment at a temperature of 260℃, a pressure of 2 MPa, and a space velocity of 12 h⁻¹. -1 The arsenic removal reaction was carried out under the reaction conditions of hydrogen / oil = 300. When the arsenic removal rate of the product was <90%, the arsenic capacity experiment was stopped, and the As content was determined by X-ray diffraction spectroscopy (XRF analysis) to obtain the arsenic capacity of the catalyst.
[0070] Table 2 Properties of Crude Oil
[0071]
[0072]
[0073] Table 3 Summary of Evaluation Results
[0074]
[0075]
[0076] Comparative analysis revealed that the hydroarsenic removal catalyst prepared using this invention exhibits significantly higher arsenic capacity and removal efficiency compared to the catalyst prepared in the comparative example. Even when treating naphtha feedstock with a high arsenic content (810 ppb) at high space velocities, it still meets the requirement of an arsenic content of less than 1 ppb in the product. (12h) -1The arsenic capacity obtained by treating high-arsenic-containing raw materials under high space velocity conditions is significantly higher than that of the comparative example. This indicates that the hydroarsenic removal catalyst prepared by the method of the present invention adopts a multi-stage composite pore expansion method during the impregnation process, which ensures the flowability of macromolecular arsenic in the catalyst while retaining more arsenic poisoning sites on the catalyst surface, improves the rapid arsenic removal reaction environment under high space velocity, enables the product to meet the requirements of ultra-deep arsenic removal (<1ppb), and further improves the utilization rate of arsenic poisoning sites in the catalyst channels, thereby increasing the arsenic capacity of the catalyst and meeting the long-term operation indicators of the catalyst.
[0077] Of course, the present invention may have other embodiments and variations. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and variations according to the present invention, but these corresponding changes and variations should all fall within the protection scope of the claims of the present invention.
Claims
1. A method for preparing a multi-stage composite pore-expanding catalyst for the hydrodearsenic removal of oil products, characterized in that, Includes the following steps: (1) Complexing agent I, pore-expanding agent II, pore-expanding agent III, active component IV containing group VIB metal and deionized water are formulated into stable dispersion impregnation component A-1; (2) Dissolve the component containing Group VIII metal in the stable dispersion impregnation component A-1 to form a stable complex impregnation solution A-2; (3) The porous support Z was impregnated with stable complex impregnation solution A-2, and then dried and calcined to obtain catalyst C1; (4) Dissolve organic auxiliary agent V and activator VI in deionized water, impregnate catalyst C1, and after drying and calcination, obtain the final hydrogen arsenic removal catalyst C2; Wherein, the Group VIB metal is at least one of molybdenum and tungsten; The molecular weight of the pore-expanding agent III in step (1) is smaller than that of the pore-expanding agent II. In step (1), the complexing agent I is ammonia or a hydroxy acid compound, including one of ethylene glycol, glyceric acid, malic acid, citric acid, tartaric acid, and gluconic acid; The component containing Group VIII metal is a nickel salt, including at least one of nickel nitrate, nickel acetate, nickel sulfate, and nickel basic carbonate. In step (4), the organic additive V is an alcohol, including at least one of ethanol, glycerol, ethylene glycol, and polyethylene glycol; In step (4), the molecular weight of the alcohol in the organic auxiliary agent V is smaller than the molecular weight of the pore-expanding agent III; In step (4), the activating agent VI is at least one of phosphoric acid, phosphate and boric acid.
2. The preparation method according to claim 1, characterized in that, The complexing agent I is ammonia or citric acid.
3. The preparation method according to claim 1, characterized in that, In step (1), the pore-expanding agent II and pore-expanding agent III are at least one of glycerol, propylene glycol, 1,4-butanediol, pentaerythritol, ethylene glycol, polyethylene glycol, diethylene glycol, polyvinyl alcohol, sodium stearate, carboxymethyl cellulose, and soluble starch.
4. The preparation method according to claim 3, characterized in that, In step (1), the pore-expanding agent II and pore-expanding agent III are at least one of glycerol, ethylene glycol, polyethylene glycol, sodium carboxymethyl cellulose, and soluble starch.
5. The preparation method according to claim 1, characterized in that, In step (1), the content of the pore-expanding agent II accounts for 0.5~20wt% of the porous carrier Z; the content of the pore-expanding agent III accounts for 0.5~20wt% of the porous carrier Z.
6. The preparation method according to claim 5, characterized in that, In step (1), the content of the pore-expanding agent II accounts for 1 to 16 wt% of the porous carrier Z.
7. The preparation method according to claim 5, characterized in that, In step (1), the content of the pore-expanding agent III accounts for 1 to 16 wt% of the porous carrier Z.
8. The preparation method according to claim 1, characterized in that, The auxiliary active component IV containing Group VIB metals is a soluble salt, soluble acid solution, or oxide of molybdenum or tungsten.
9. The preparation method according to claim 8, characterized in that, The auxiliary active component IV containing Group VIB metals is molybdate or molybdenum trioxide.
10. The preparation method according to claim 1, characterized in that, The component containing Group VIII metal is a nickel nitrate or a nickel basic carbonate.
11. The preparation method according to claim 1, characterized in that, The hydrodearsenic removal catalyst C2 contains 5-24 wt% NiO, 0.5-24 wt% MoO3 and WO3, and 52-94.5 wt% support.
12. The preparation method according to claim 1, characterized in that, The hydrodearsenic removal catalyst C2 contains 6-21 wt% NiO, 1-15 wt% MoO3 or WO3, and 64-93 wt% support.
13. The preparation method according to claim 1, characterized in that, The porous carrier Z is one or more composite carriers of alumina, titanium dioxide, silicon dioxide, and magnesium oxide.
14. The preparation method according to claim 13, characterized in that, The porous carrier Z is alumina.
15. The preparation method according to claim 1, characterized in that, In step (1) or step (2), the temperature during the preparation of the stable dispersion impregnation component A-1 or the stable dispersion impregnation component A-2 is 10~100℃, the temperature does not exceed the boiling point of the pore-expanding aid II and the pore-expanding aid III, and the mixing time is 10min~120min.
16. The preparation method according to claim 1, characterized in that, In step (4), the amount of organic additive V added is 0.5 to 16 wt% of the mass of catalyst C1.
17. The preparation method according to claim 16, characterized in that, In step (4), the amount of organic additive V added is 1 to 10 wt% of the mass of catalyst C1.
18. The preparation method according to claim 1, characterized in that, In step (4), the amount of activator VI added is 1 to 10 wt% of the mass of catalyst C1.
19. The preparation method according to claim 18, characterized in that, In step (4), the amount of activator VI added is 3 to 7 wt% of the mass of catalyst C1.
20. The preparation method according to claim 1, characterized in that, In step (3) or step (4), after impregnation, it is necessary to let it stand for 1 to 7 hours before drying and calcining; the drying temperature is 50 to 150°C and the drying time is 3 to 6 hours; the calcining temperature is 300°C to 600°C and the calcining time is 3 to 6 hours.
21. The preparation method according to claim 1, characterized in that, In step (3) or step (4), the impregnation process is saturated impregnation or supersaturated impregnation.
22. The preparation method according to claim 1, characterized in that, The hydro-dearsenic removal catalyst C2 is used in a sulfided form during the dearsenic removal process in oil processing.
23. A multi-stage composite pore-expanding catalyst for the hydrodearsenic removal of oil products, characterized in that, It is obtained by the preparation method according to any one of claims 1-22.