Bio-based deoxidized oil hydroisomerization and cracking catalyst

Abstract

The invention discloses a bio-based deoxidized oil hydroisomerization and cracking catalyst, the bio-based deoxidized oil hydroisomerization and cracking catalyst comprises a modified SAPO-11 molecular sieve and an active metal, a preparation method of the modified SAPO-11 molecular sieve comprises the following steps: mixing a silicon source, an aluminum source, water, a co-metal and a template agent to obtain an initial gel, and carrying out a hydrothermal reaction, drying and roasting on the initial gel to obtain the modified SAPO-11 molecular sieve, the auxiliary metal is one or more of chromium, zirconium and copper. The catalyst is low in preparation cost and good in thermal stability.

Description

Technical Field

[0001] This invention belongs to the field of catalyst technology, specifically relating to a bio-based deoxygenated oil hydroisomerization and cracking catalyst. Background Technology

[0002] The development of the aviation industry has facilitated travel and promoted economic development, but at the same time, the burning of traditional fossil fuels by aircraft emits large amounts of CO2, causing significant environmental problems globally. To address climate change, the International Air Transport Association (IATA), representing the entire aviation industry, proposed three major commitments to the International Civil Aviation Organization (ICAO): improving fuel efficiency by an average of 1.5% annually from 2009 to 2020; achieving zero carbon emissions growth from 2021 to 2035; and reducing carbon emissions by 50% by 2050 compared to 2005 levels. Achieving these emission reduction targets is difficult under the existing fuel system and requires alternative technologies, with aviation biofuels being the most promising low-carbon product.

[0003] The production of aviation kerosene from biomass oil generally employs a two-step process. First, biomass oil or waste oil is converted into long-chain n-alkanes (C16-C18) through reactions such as hydrogenation saturation, deoxygenation, decarbonylation, and decarboxylation. Then, hydrocracking / isomerization yields aviation kerosene components (C9-C16). The core of this process is the selection of catalysts for the hydrocracking / isomerization of long-chain n-alkanes. Currently, there is relatively more research on hydrocracking / isomerization catalysts for long-chain n-alkanes (single hydrocarbons) from fossil fuels, while research on hydrocracking / isomerization catalysts for mixed hydrocarbons from biomass is limited. Bifunctional catalysts such as Pt / ZSM-5, Pt / ZSM-22, and Pt / SAPO-11 used for the hydrocracking / isomerization of long-chain n-alkanes suffer from low bio-aviation kerosene yields or high costs.

[0004] CN102876348A discloses a method for producing biodiesel via hydrogenation. Vegetable oil is first hydrorefined, and the hydrorefining effluent enters a gas-liquid separator above a hydrodewaxing reactor for gas-liquid separation. The separated refined oil is then redistributed via trays and flows countercurrently with hydrogen through a hydrodewaxing catalyst bed to separate the dewaxing product and obtain the biodiesel. The catalyst support used is γ-Al₂O₃, which, under long-term hydrothermal conditions, causes the catalyst structure to collapse, reducing the specific surface area and pore volume, and lowering its mechanical strength.

[0005] CN110862873A discloses a method for catalytically directed hydrodeoxygenation of oils to prepare hydrogenated biodiesel, belonging to the technical field of hydrogenated biodiesel preparation. It employs a molecular sieve-supported catalyst to catalyze the hydrodeoxygenation reaction of oil feedstock via hydrodecarboxylation / decarbonylation to obtain hydrogenated biodiesel. The total content of pentadecane and heptadecane in the hydrogenated biodiesel is greater than 85%. The active component of the catalyst is Ni2P, and the amount of catalyst used is 5%-10% of the weight of the reacting oil feedstock. The main components of the hydrogenated biodiesel are pentadecane and heptadecane. This invention exhibits a directed hydrodecarboxylation / decarbonylation selectivity greater than 80%, reducing the generation of water during the reaction, avoiding the catalyst's tendency to deactivate upon contact with water, and extending the catalyst's lifespan. The reaction conversion rate for preparing hydrogenated biodiesel using this invention is greater than 95%, and it significantly reduces the temperature and time of the oil hydrodeoxygenation reaction, significantly reducing reaction energy consumption and cost. The catalyst used is a molecular sieve-supported catalyst, namely Ni2P / SAPO-11. The presence of phosphides will generate a large amount of phosphating wastewater, resulting in high treatment costs and serious environmental pollution.

[0006] CN103721741A discloses a hydrodeoxygenation catalyst and a hydroisomerization catalyst for the hydrogenation of castor oil to biodiesel, as well as their application methods. The hydrodeoxygenation catalyst uses one of SAPO-11, ZSM-5, or γ-Al₂O₃ as a support, Zn as an auxiliary agent, and one of Ni, Ni₂P, Fe, Pd, Pt, MoP, or CoP as the active component. The hydroisomerization catalyst uses one of SAPO-34, ZSM-22, or MCM-41 as a support, Zn as an auxiliary agent, and one or both Ni and Ag as the active component. In a high-pressure fixed-bed reactor, castor oil undergoes hydrodeoxygenation and hydroisomerization reactions. The resulting product is fractionated, and the 170-350℃ fraction is selected as the biodiesel suitable for use. This technology does not address how to improve the catalyst's tolerance to oxygen and water. While increasing the reaction temperature of the hydrodeoxygenation reaction of oils and fats can improve the oxygen removal rate, it also leads to an increase in side reactions such as hydrodecarboxylation, hydrodecarbonylation, and hydrocracking, generating more byproducts such as CO, CO2, gaseous hydrocarbons, and light hydrocarbons, thus reducing the yield of diesel and jet fuel fractions in the hydroisomerization stage of oils and fats. Summary of the Invention

[0007] The purpose of this invention is to provide a bio-based deoxygenated oil hydroisomerization and cracking catalyst to solve the problems of high catalyst preparation cost and poor thermal stability in the prior art.

[0008] To achieve the above objectives, the present invention provides a bio-based deoxygenated oil hydroisomerization and cracking catalyst, comprising a modified SAPO-11 molecular sieve and an active metal. The modified SAPO-11 molecular sieve is prepared by mixing a silicon source, an aluminum source, water, a cooperating metal and a template agent to obtain an initial gel. The initial gel is subjected to hydrothermal reaction, drying and calcination to obtain the modified SAPO-11 molecular sieve. The cooperating metal is one or more of chromium, zirconium and copper.

[0009] The bio-based deoxygenated oil hydroisomerization and cracking catalyst of the present invention has an initial gel with a molar composition ratio of (0.5-2)M:(0.05-0.25)K2O or Na2O:(10-50)templator:(0.01-0.05)Al2O3:(0.5-1)SiO2:(10-60)H2O, wherein M is a co-metal oxide.

[0010] The bio-based deoxygenated oil hydroisomerization and cracking catalyst of the present invention uses one or more of 1,6-hexanediamine, diethanolamine, diethylamine, and n-butylamine as the template agent.

[0011] The bio-based deoxygenated oil hydroisomerization and cracking catalyst of the present invention has Pt and / or Pd as the active metal.

[0012] The bio-based deoxygenated oil hydroisomerization and cracking catalyst of this invention, wherein the active metal, calculated as elemental, has a content of 0.3 wt.%-0.5 wt.% of the molecular sieve mass.

[0013] The bio-based deoxygenated oil hydroisomerization and cracking catalyst of the present invention has the following hydrothermal reaction conditions: reaction temperature 120-200℃, reaction time 8-36h.

[0014] The bio-based deoxygenated oil hydroisomerization and cracking catalyst of the present invention has a calcination temperature of 400-600℃ during the preparation of modified SAPO-11 molecular sieve.

[0015] The bio-based deoxygenated oil hydroisomerization and cracking catalyst of the present invention has the active metal loaded onto a molecular sieve by impregnation.

[0016] The bio-based deoxygenated oil hydroisomerization and cracking catalyst of the present invention further includes drying and calcination steps after the active metal impregnation is completed.

[0017] The bio-based deoxygenated oil hydroisomerization and cracking catalyst of the present invention is dried at 100-120℃ for 6-24 hours after impregnation, and calcined at 400-600℃ for 6-12 hours.

[0018] Beneficial effects of this invention:

[0019] This invention utilizes hydrothermal synthesis technology to design and synthesize a chromium, zirconium, and copper-modified SAPO-11 molecular sieve support with high porosity and chemical stability. This support not only possesses excellent molecular sieve performance but also effectively inhibits catalyst poisoning and deactivation. The modified molecular sieve exhibits better thermal stability, enhancing its catalytic activity under high temperature and high pressure environments.

[0020] In a 20 mL fixed-bed reactor, the prepared hydroisomerization catalyst was used to carry out hydroisomerization and cracking reactions on bio-based deoxygenated oil. The experimental results showed that the prepared hydroisomerization catalyst has high activity and stability and can effectively remove unsaturated hydrocarbons and impurities from bio-based deoxygenated oil to generate high-quality fuel. Detailed Implementation

[0021] The present invention will now be described in detail through embodiments. It should be noted that the following embodiments are only for further illustration of the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above description.

[0022] Example 1

[0023] Preparation of the modified support: The molar ratio of the gel composition was 0.5ZrO2:0.16K2O:25DAH:0.01Al2O3:1.0SiO2:40H2O. Zirconium oxychloride octahydrate, potassium hydroxide, and water were mixed in a beaker, followed by the addition of boehmite (Al2O3, 64%), 1,6-hexanediamine (DAH), and silica sol. The mixture was stirred to form an initial gel, which was then transferred to a stainless steel high-pressure reactor with a polytetrafluoroethylene liner. The crystallization temperature was 180℃, and the crystallization time was 24 h. After crystallization, the reactor was cooled to room temperature. The product was centrifuged and washed until the solution was neutral, then dried in an oven and calcined in a muffle furnace at 550℃ to obtain an acidic zirconium-modified SAPO-11 molecular sieve sample.

[0024] Loading of active metal: A certain amount of molecular sieve support was weighed and loaded with chloroplatinic acid (0.3 wt.%) by the equal volume impregnation method. The mixture was stirred and allowed to stand for 12 h, dried at 110 °C for 12 h, and calcined in a muffle furnace at 550 °C for 6 h to obtain the Pt / Zr / SAPO-11 hydroisomerization catalyst.

[0025] The hydroisomerization catalyst was placed in a 20 ml hydroisomerization apparatus. The feedstock was biomass deoxygenated oil with an oxygen content of <100 ppm. The reaction was carried out at a temperature of 400℃, a pressure of 6 MPa, and a volume hourly space velocity of 1 h⁻¹. -1Hydrogenation was carried out at a hydrogen-to-oil volume ratio of 1000:1 for 8 hours, followed by liquid-phase product collection every 2 hours. After 48 hours of operation, the liquid yield was calculated. Isomerization conversion and jet fuel yield were determined by gas chromatography. The C9-C18 isomerization conversion rate in the deoxygenated oil was 87%, the bio-jet fuel yield was 62%, the catalyst strength was >200 N / cm, and the catalyst lifetime was >1000 hours.

[0026] Example 2

[0027] The initial gel molar composition was 0.5CuO:0.05Na₂O:25DAH:0.05Al₂O₃:0.5SiO₂:10H₂O, with Pd as the active metal at a loading of 0.5 wt.%. Zirconium oxychloride octahydrate, potassium hydroxide, and water were mixed in a beaker, followed by the addition of boehmite (Al₂O₃, 64%), 1,6-hexanediamine (DAH), and silica sol. The mixture was stirred to form the initial gel, which was then transferred to a stainless steel high-pressure reactor lined with polytetrafluoroethylene (PTFE). The crystallization temperature was 120 °C, and the crystallization time was 36 h. After crystallization, the reactor was cooled to room temperature. The product was centrifuged and washed until the solution was neutral, then dried in an oven and calcined in a muffle furnace at 400 °C to obtain an acidic zirconium-modified SAPO-11 molecular sieve sample.

[0028] Loading of active metal: A certain amount of molecular sieve support was weighed and loaded with chloroplatinic acid (0.3 wt.%) by the equal volume impregnation method. The mixture was stirred and allowed to stand for 12 h, dried at 100 °C for 24 h, and calcined in a muffle furnace at 600 °C for 10 h to obtain the Pt / Zr / SAPO-11 hydroisomerization catalyst.

[0029] Hydroisomerization was evaluated using a 20ml hydroisomerization apparatus under the same conditions as in Example 1. The C9-C18 isomerization conversion rate in the deoxygenated oil was 80%, the bio-jet fuel yield was 57%, the catalyst strength was >200 N / cm, and the catalyst lifetime was >1000 h.

[0030] Example 3

[0031] The initial gel molar composition was 0.5Cr₂O₃:0.16K₂O:25DAH:0.02Al₂O₃:0.7SiO₂:40H₂O. Zirconium oxychloride octahydrate, potassium hydroxide, and water were mixed in a beaker, followed by the addition of boehmite (Al₂O₃, 64%), 1,6-hexanediamine (DAH), and silica sol. The mixture was stirred to form the initial gel, which was then transferred to a stainless steel high-pressure reactor lined with polytetrafluoroethylene (PTFE). The crystallization temperature was 200℃, and the crystallization time was 8 hours. After crystallization, the reactor was cooled to room temperature. The product was centrifuged and washed until the solution was neutral, then dried in an oven and calcined in a muffle furnace at 600℃ to obtain an acidic zirconium-modified SAPO-11 molecular sieve sample.

[0032] Support for active metals: A certain amount of molecular sieve support was weighed and loaded with chloroplatinic acid (0.3 wt.%) by the equal volume impregnation method. The mixture was stirred and allowed to stand for 12 h, dried at 120 °C for 6 h, and calcined in a muffle furnace at 400 °C for 12 h to obtain the Pt / Zr / SAPO-11 hydroisomerization catalyst.

[0033] Hydroisomerization was evaluated using a 20ml hydroisomerization apparatus under the same conditions as in Example 1. The C9-C18 isomerization conversion rate in the deoxygenated oil was 85%, the bio-jet fuel yield was 61%, the catalyst strength was >200 N / cm, and the catalyst lifetime was >1000 h.

[0034] Example 4

[0035] The initial gel molar composition ratio was 0.5ZrO:0.5CuO:0.5Cr2O3:0.16K2O:15DAH:0.01Al2O3:1.0SiO2:40H2O. The remaining catalyst preparation steps were the same as in Example 1.

[0036] Hydroisomerization was evaluated using a 20ml hydroisomerization apparatus under the same conditions as in Example 1. The C9-C18 isomerization conversion rate in the deoxygenated oil was 88%, the bio-jet fuel yield was 63%, the catalyst strength was >200 N / cm, and the catalyst lifetime was >1000 h.

[0037] Example 5

[0038] The initial gel molar composition ratio was 0.5ZrO:0.5CuO:0.25K2O:50DAH:0.01Al2O3:0.9SiO2:60H2O, and the rest of the catalyst preparation steps were the same as in Example 1.

[0039] Hydroisomerization was evaluated using a 20ml hydroisomerization apparatus under the same conditions as in Example 1. The C9-C18 isomerization conversion rate in the deoxygenated oil was 83%, the bio-jet fuel yield was 60%, the catalyst strength was >200 N / cm, and the catalyst lifetime was >1000 h.

[0040] Example 6

[0041] The initial gel molar composition ratio was 0.5ZrO:0.5Cr2O3:0.16K2O:25DAH:0.01Al2O3:1.0SiO2:40H2O, and the rest of the catalyst preparation steps were the same as in Example 1.

[0042] Hydroisomerization was evaluated using a 20ml hydroisomerization apparatus under the same conditions as in Example 1. The C9-C18 isomerization conversion rate in the deoxygenated oil was 87%, the bio-jet fuel yield was 62%, the catalyst strength was >200 N / cm, and the catalyst lifetime was >1000 h.

[0043] Comparative Example 1

[0044] The catalyst was prepared in the same way as in Example 1, except that zirconium was not added during the preparation of the support.

[0045] Hydroisomerization was evaluated on a 20ml hydroisomerization apparatus under the same conditions as in Example 1: the C9-C18 isomerization conversion rate in the deoxygenated oil was 80%, the bio-jet fuel yield was 55%, the catalyst strength was 165 N / cm, and the catalyst lifetime was 800 h.

[0046] Comparative Example 2

[0047] The catalyst was prepared in the same way as in Example 1, except that the zirconium source was loaded onto the catalyst by impregnation.

[0048] Hydroisomerization was evaluated on a 20ml hydroisomerization apparatus under the same conditions as in Example 1. The isomerization conversion rate of C9-C18 in the deoxygenated oil was 77%, the bio-jet fuel yield was 49%, the catalyst strength was >200 N / cm, and the catalyst lifetime was 500 h.

[0049] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the claims of the present invention.

Claims

1. A bio-based deoxygenated oil hydroisomerization and cracking catalyst, characterized in that, The product includes a modified SAPO-11 molecular sieve and an active metal. The modified SAPO-11 molecular sieve is prepared by mixing a silicon source, an aluminum source, water, a cooperating metal and a template agent to obtain an initial gel. The initial gel is subjected to hydrothermal reaction, drying and calcination to obtain the modified SAPO-11 molecular sieve. The cooperating metal is one or more of chromium, zirconium and copper.

2. The bio-based deoxygenated oil hydroisomerization and cracking catalyst according to claim 1, characterized in that, The initial gel has a molar composition ratio of (0.5-2)M:(0.05-0.25)K2O or Na2O:(10-50)template agent:(0.01-0.05)Al2O3:(0.5-1)SiO2:(10-60)H2O, where M is a metal oxide.

3. The bio-based deoxygenated oil hydroisomerization and cracking catalyst according to claim 1 or 2, characterized in that, The template agent is one or more of 1,6-hexanediamine, diethanolamine, diethylamine, and n-butylamine.

4. The bio-based deoxygenated oil hydroisomerization and cracking catalyst according to claim 1, characterized in that, The active metal is Pt and / or Pd.

5. The bio-based deoxygenated oil hydroisomerization and cracking catalyst according to claim 1, characterized in that, The active metal, calculated as an element, has a content of 0.3 wt.% to 0.5 wt.% of the molecular sieve mass.

6. The bio-based deoxygenated oil hydroisomerization and cracking catalyst according to claim 1, characterized in that, The hydrothermal reaction conditions are: reaction temperature 120-200℃, reaction time 8-36h.

7. The bio-based deoxygenated oil hydroisomerization and cracking catalyst according to claim 1, characterized in that, The calcination temperature during the preparation of modified SAPO-11 molecular sieve is 400-600℃.

8. The bio-based deoxygenated oil hydroisomerization and cracking catalyst according to claim 1, characterized in that, The active metal is loaded onto the molecular sieve by impregnation.

9. The bio-based deoxygenated oil hydroisomerization and cracking catalyst according to claim 8, characterized in that, The process after the active metal impregnation is completed also includes drying and roasting steps.

10. The bio-based deoxygenated oil hydroisomerization and cracking catalyst according to claim 9, characterized in that, The drying conditions after impregnation are 100-120℃ for 6-24 hours, and the calcination conditions are 400-600℃ for 6-12 hours.