A preparation method of a bio-oil one-step hydrodeoxygenation isomerization supported bifunctional catalyst

Abstract

The application discloses a preparation method of a bio-oil one-step hydrodeoxygenation isomerization supported bifunctional catalyst. Tetraethyl silicate and ethanol are stirred in a beaker at room temperature to obtain solution I, ammonia water and ethanol are stirred in a beaker at room temperature to obtain solution II; solution II is added into solution I under stirring at room temperature, and then continuous stirring is carried out to form a transparent sol, and then aging, suction filtration, water washing, drying and grinding are carried out to obtain a silicon dioxide carrier; the silicon dioxide carrier and phosphomolybdic acid are dissolved in deionized water, rotary evaporation and vacuum drying are carried out, and then the bio-oil one-step hydrodeoxygenation isomerization supported bifunctional catalyst is obtained. The bio-oil one-step hydrodeoxygenation isomerization supported bifunctional catalyst prepared by the method can realize bio-oil one-step hydrodeoxygenation reaction, avoids problems such as easy cracking of intermediate products in conventional reactions, and has simple catalyst preparation method and high industrial application potential.

Description

Technical Field

[0001] This invention relates to a method for preparing a one-step hydrodeoxygenation isomeric supported bifunctional catalyst for bio-oils, belonging to the field of petrochemical technology. Background Technology

[0002] Energy is fundamental to human survival; however, due to overexploitation and utilization, fossil fuels are being depleted, making the development of renewable and clean energy sources an urgent priority. Solar energy, biomass energy, and wind energy are all common renewable energy sources. Biomass energy originates from plant photosynthesis and is stored in biomass. Biodiesel and biojet fuels, as renewable and sustainable energy sources, can effectively reduce carbon dioxide emissions, mitigate the greenhouse effect, and meet green and low-carbon requirements. Therefore, processing bio-oils into biofuels is currently one of the hot research topics in the petrochemical field.

[0003] The development of biofuel conversion from bio-oils has gone through two main stages: first-generation and second-generation. First-generation biodiesel is produced by esterifying vegetable oils or animal fats with methanol to obtain fatty acid methyl esters. This technology is quite mature and has achieved large-scale production globally. Compared to traditional petroleum diesel, first-generation biodiesel has advantages such as environmental friendliness, high cetane number, and renewability. However, it still has shortcomings in low-temperature fluidity, oxygen content, stability, and calorific value, so it is usually only used as an additive to petroleum diesel, with an addition ratio generally not exceeding 5%. The second-generation preparation method involves converting oils into a hydrocarbon mixture similar to petroleum diesel through a hydrodeoxygenation reaction, namely biodiesel and biojet fuel. Compared to first-generation biodiesel, second-generation biofuels not only retain the advantages of environmental friendliness, high cetane number, and renewability, but also have better fluidity, lower oxygen content, higher stability, and higher calorific value, and can be mixed with petroleum diesel in any proportion. The core of the second-generation biofuel production process lies in the catalyst. Heteropoly acids, due to their unique acidity, redox properties, and stability, are widely used in the catalytic field and exhibit high activity in isomerization reactions. The dispersion of active metals has a significant impact on catalyst activity, and anchoring active metals on a support is a strategy to improve dispersibility. Silica (SiO2) has advantages such as a high specific surface area, strong structural tunability, and stable chemical properties, which can provide more active sites. Summary of the Invention

[0004] This invention aims to solve the problem that existing catalysts are easily deactivated by combining with free carboxylic acids in waste oils. It provides a method for preparing a one-step hydrodeoxygenation isomer supported bifunctional catalyst for bio-oils, which realizes the one-step hydrodeoxygenation reaction of bio-oils and avoids the problem of easy cracking of intermediate products in conventional reactions. Moreover, the catalyst preparation method is simple and has high potential for industrial application.

[0005] The technical solution adopted in this invention is as follows:

[0006] A method for preparing a one-step hydrodeoxygenation isomeric supported bifunctional catalyst for bio-oils includes the following steps:

[0007] S1: Add tetraethyl silicate and organic solvent to a beaker and stir at room temperature for 30-60 min to obtain solution I; add ammonia and organic solvent to a beaker and stir at room temperature for 30-60 min to obtain solution II; add solution II to solution I while stirring at room temperature, and continue stirring to form a transparent sol. Then, let it stand at room temperature for 24-48 h, filter, wash the filter cake with deionized water, dry the filter cake under vacuum for 12 h, and grind it to obtain SiO2 support;

[0008] S2: Add SiO2 support and phosphomolybdic acid to a beaker, add deionized water, stir and dissolve at room temperature for 1-4 hours, rotary evaporate until the water evaporates, and vacuum dry for 12-24 hours to obtain a one-step hydrodeoxygenation isomer supported bifunctional catalyst for bio-oil.

[0009] In step S1, the volume ratio of tetraethyl silicate to organic solvent in solution I is 3:40; the volume ratio of ammonia to organic solvent in solution II is 1:20; the volume ratio of tetraethyl silicate to ammonia in the transparent sol is 3:2; the organic solvent is selected from any one of ethanol, acetone, and isopropanol; the concentration of ammonia is 25 vol%; and the vacuum drying temperature is 50–70°C.

[0010] In step S2, the molar ratio of the SiO2 support to phosphomolybdic acid is 1:0.01 to 0.2; the rotary evaporation temperature is 80°C; and the vacuum drying temperature is 150 to 250°C.

[0011] A one-step hydrodeoxygenation isomeric supported bifunctional catalyst for bio-oils is prepared by the above-described method.

[0012] The above-mentioned supported bifunctional catalyst for one-step hydrodeoxy isomerization of bio-oils is used in the catalytic hydrodeoxy isomerization of bio-oils;

[0013] The bio-oil is any one of methyl palmitate, waste oil, or palm oil.

[0014] The application of the above-mentioned supported bifunctional catalyst for one-step hydrodeoxy isomerization of bio-oils in catalyzing the hydrodeoxy isomerization of bio-oils includes the following steps:

[0015] S1: Add bio-oil to the suspension bed reactor, then add the bio-oil one-step hydrodeoxygenation isomeric supported bifunctional catalyst and sublimation sulfur powder in sequence. Seal the reactor and turn on the stirrer to fully mix the raw materials to obtain a mixture.

[0016] S2: Replace the air in the reactor containing the mixture with hydrogen, and fill it with hydrogen to a certain pressure. Start the heating program at a heating rate of 4-6℃ / min. First, heat the mixture to the sulfidation temperature to carry out the sulfidation reaction, and then heat it to the cracking reaction temperature to carry out the cracking reaction.

[0017] In step S1, the mass ratio of the bio-oil and the bio-oil one-step hydrodeoxygenation isomeric supported bifunctional catalyst is 100:1 to 10; the S / Mo atomic ratio of the bio-oil one-step hydrodeoxygenation isomeric supported bifunctional catalyst and sublimed sulfur powder is 8 to 12:1.

[0018] In step S2, the pressure is 6–20 MPa; the sulfidation temperature is 200–300 °C; the sulfidation reaction time is 40–60 min; the cracking reaction temperature is 350–450 °C; and the cracking reaction time is 3–6 h.

[0019] The significant advantages of this invention are:

[0020] (1) The biological oil one-step hydrodeoxygenation isomerization supported bifunctional catalyst provided by the present invention, wherein the phosphomolybdic acid will be sulfidated to generate molybdenum sulfide under the action of the sulfiding agent and used for hydrodeoxygenation reaction, the catalyst can be recovered, and the generated phosphoric acid will continue to undergo isomerization reaction in the suspension bed reactor to achieve one-step hydrodeoxygenation isomerization, avoiding the cracking of intermediate products.

[0021] (2) The one-step hydrogenation and deoxygenation isomeric supported bifunctional catalyst for bio-oil provided by the present invention has a simple preparation method. The support used has a nanosphere structure, which greatly increases its specific surface area so that more active sites come into contact with bio-oil, thus greatly improving the conversion rate of bio-oil.

[0022] (3) The biological oil one-step hydrodeoxygenation isomerization supported bifunctional catalyst provided by the present invention can be used for one-step hydrodeoxygenation isomerization reaction of various waste oil suspension beds, and has the characteristics of high conversion rate, low coking rate and good impurity removal effect. Detailed Implementation

[0023] To make the content of this invention easier to understand, the technical solution of this invention will be further described below with reference to specific embodiments, but this invention is not limited thereto.

[0024] Example 1:

[0025] Add 6 mL of tetraethyl orthosilicate (TEOS) and 80 mL of ethanol to a beaker and stir at 800 rpm for 30 min at room temperature to obtain solution I. Add 4 mL of 25 vol% ammonia and 80 mL of ethanol to a beaker and stir at 800 rpm for 30 min at room temperature to obtain solution II. Add solution II to solution I while stirring at 800 rpm at room temperature. Continue stirring for 1 h to form a transparent sol, then allow it to stand at room temperature for 24 h. Filter the solution, wash the filter cake with deionized water, and then vacuum dry the filter cake at 80 °C for 12 h. Grind the filter cake to 60 mesh to obtain SiO2 support. Add 2 g of SiO2 support and 3.0378 g of phosphomolybdic acid to a beaker, add 50 mL of deionized water, and stir at 800 rpm at room temperature for 1 h to dissolve the solution. Evaporate the solution in a rotary evaporator at 80 °C and 30 rpm for 120 min until the water evaporates completely. Then vacuum dry the solution at 150 °C for 12 h to obtain catalyst A.

[0026] Example 2:

[0027] Add 6 mL of tetraethyl orthosilicate (TEOS) and 80 mL of ethanol to a beaker and stir at 800 rpm for 30 min at room temperature to obtain solution I. Add 4 mL of 25 vol% ammonia and 80 mL of ethanol to a beaker and stir at 800 rpm for 30 min at room temperature to obtain solution II. Add solution II to solution I while stirring at 800 rpm at room temperature. Continue stirring for 1 h to form a transparent sol, then allow it to stand at room temperature for 24 h. Filter the solution, wash the filter cake with deionized water, and then vacuum dry the filter cake at 80 °C for 12 h. Grind the filter cake to 60 mesh to obtain SiO2 support. Add 2 g of SiO2 support and 6.0781 g of phosphomolybdic acid to a beaker, add 50 mL of deionized water, and stir at 800 rpm at room temperature for 1 h to dissolve the solution. Evaporate the solution in a rotary evaporator at 80 °C and 30 rpm for 120 min until the water evaporates completely. Then vacuum dry the solution at 150 °C for 12 h to obtain catalyst B.

[0028] Example 3:

[0029] Add 6 mL of tetraethyl orthosilicate (TEOS) and 80 mL of ethanol to a beaker and stir at 800 rpm for 30 min at room temperature to obtain solution I. Add 4 mL of 25 vol% ammonia and 80 mL of ethanol to a beaker and stir at 800 rpm for 30 min at room temperature to obtain solution II. Add solution II to solution I while stirring at 800 rpm at room temperature. Continue stirring for 1 h to form a transparent sol, then allow it to stand at room temperature for 24 h. Filter the solution, wash the filter cake with deionized water, and then vacuum dry the filter cake at 80 °C for 12 h. Grind the filter cake to 60 mesh to obtain SiO2 support. Add 2 g of SiO2 support and 9.1171 g of phosphomolybdic acid to a beaker, add 50 mL of deionized water, and stir at 800 rpm at room temperature for 1 h to dissolve the solution. Evaporate the solution in a rotary evaporator at 80 °C and 30 rpm for 120 min until the water evaporates completely. Then vacuum dry the solution at 150 °C for 12 h to obtain catalyst C.

[0030] Example 4:

[0031] Add 6 mL of tetraethyl orthosilicate (TEOS) and 80 mL of ethanol to a beaker and stir at 800 rpm for 30 min at room temperature to obtain solution I. Add 4 mL of 25 vol% ammonia and 80 mL of ethanol to a beaker and stir at 800 rpm for 30 min at room temperature to obtain solution II. Add solution II to solution I while stirring at 800 rpm at room temperature. Continue stirring for 1 h to form a transparent sol, then allow it to stand at room temperature for 24 h. Filter the solution, wash the filter cake with deionized water, and then vacuum dry the filter cake at 80 °C for 12 h. Grind the filter cake to 60 mesh to obtain SiO2 support. Add 2 g of SiO2 support and 12.1562 g of phosphomolybdic acid to a beaker, add 50 mL of deionized water, and stir at 800 rpm at room temperature for 1 h to dissolve the solution. Evaporate the solution in a rotary evaporator at 80 °C and 30 rpm for 120 min until the water evaporates completely. Then vacuum dry the solution at 150 °C for 12 h to obtain catalyst D.

[0032] Example 5:

[0033] Add 6 mL of tetraethyl orthosilicate (TEOS) and 80 mL of ethanol to a beaker and stir at 800 rpm for 30 min at room temperature to obtain solution I. Add 4 mL of 25 vol% ammonia and 80 mL of ethanol to a beaker and stir at 800 rpm for 30 min at room temperature to obtain solution II. Add solution II to solution I while stirring at 800 rpm at room temperature. Continue stirring for 1 h to form a transparent sol, then allow it to stand at room temperature for 24 h. Filter the solution, wash the filter cake with deionized water, and then vacuum dry the filter cake at 80 °C for 12 h. Grind the filter cake to 60 mesh to obtain SiO2 support. Add 2 g of SiO2 support and 15.1952 g of phosphomolybdic acid to a beaker, add 50 mL of deionized water, and stir at 800 rpm at room temperature for 1 h to dissolve the solution. Evaporate the solution in a rotary evaporator at 80 °C and 30 rpm for 120 min until the water evaporates completely. Then vacuum dry the solution at 150 °C for 12 h to obtain catalyst E.

[0034] Example 6:

[0035] Add 6 mL of tetraethyl orthosilicate (TEOS) and 80 mL of ethanol to a beaker and stir at 800 rpm for 30 min at room temperature to obtain solution I. Add 4 mL of 25 vol% ammonia and 80 mL of ethanol to a beaker and stir at 800 rpm for 30 min at room temperature to obtain solution II. Add solution II to solution I while stirring at 800 rpm at room temperature. Continue stirring for 2 h to form a transparent sol, then allow it to stand at room temperature for 24 h. Filter the solution, wash the filter cake with deionized water, and then vacuum dry the filter cake at 80 °C for 12 h. Grind the filter cake to 60 mesh to obtain SiO2 support. Add 2 g of SiO2 support and 9.1171 g of phosphomolybdic acid to a beaker, add 50 mL of deionized water, and stir at 800 rpm at room temperature for 1 h to dissolve the solution. Evaporate the solution in a rotary evaporator at 80 °C and 30 rpm for 120 min until the water evaporates completely. Then vacuum dry the solution at 200 °C for 12 h to obtain catalyst F.

[0036] Example 7:

[0037] Add 6 mL of tetraethyl orthosilicate (TEOS) and 80 mL of ethanol to a beaker and stir at 800 rpm for 30 min at room temperature to obtain solution I. Add 4 mL of 25 vol% ammonia and 80 mL of ethanol to a beaker and stir at 800 rpm for 30 min at room temperature to obtain solution II. Add solution II to solution I while stirring at 800 rpm at room temperature. Continue stirring for 1 h to form a transparent sol, then allow it to stand at room temperature for 24 h. Filter the solution, wash the filter cake with deionized water, and then vacuum dry the filter cake at 80 °C for 12 h. Grind the filter cake to 60 mesh to obtain SiO2 support. Add 2 g of SiO2 support and 9.1171 g of phosphomolybdic acid to a beaker, add 50 mL of deionized water, and stir at 800 rpm at room temperature for 1 h to dissolve the solution. Evaporate the solution in a rotary evaporator at 80 °C and 30 rpm for 120 min until the water evaporates completely. Then vacuum dry the solution at 150 °C for 24 h to obtain catalyst G.

[0038] Example 8:

[0039] Add 6 mL of tetraethyl orthosilicate (TEOS) and 80 mL of ethanol to a beaker and stir at 800 rpm for 30 min at room temperature to obtain solution I. Add 4 mL of 25 vol% ammonia and 80 mL of ethanol to a beaker and stir at 800 rpm for 30 min at room temperature to obtain solution II. Add solution II to solution I while stirring at 800 rpm at room temperature. Continue stirring for 2 h to form a transparent sol, then allow it to stand at room temperature for 48 h. Filter the solution, wash the filter cake with deionized water, and then vacuum dry the filter cake at 80 °C for 12 h. Grind the filter cake to 60 mesh to obtain SiO2 support. Add 2 g of SiO2 support and 9.1171 g of phosphomolybdic acid to a beaker, add 50 mL of deionized water, and stir at 800 rpm at room temperature for 1 h to dissolve the solution. Evaporate the solution in a rotary evaporator at 80 °C and 30 rpm for 120 min until the water evaporates completely. Then vacuum dry the solution at 150 °C for 12 h to obtain catalyst H.

[0040] Application examples

[0041] The one-step hydrodeoxygenation isomerization supported bifunctional catalysts prepared in Examples 2, 3, 4, and 6 were used to evaluate the hydrodeoxygenation isomerization of methyl palmitate in a suspended bed. The experimental steps were as follows: 40g of methyl palmitate was weighed and added to a 300mL suspended bed reactor, followed by 2g of catalyst and 0.4172g of sublimed sulfur powder. The reactor was sealed and stirred to ensure thorough mixing at a stirring rate of 550r / min. The air in the reactor was replaced with hydrogen, and then hydrogen was introduced to a pressure of 20MPa. The heating program was started at a rate of 5℃ / min. The temperature was first increased to 250℃ for sulfidation reaction for 40min, and then increased to 400℃ for cracking reaction for 5h. After the reaction was completed, the reactor was cooled to room temperature, and the product was collected for vacuum distillation. The distillation residue was washed with toluene, centrifuged, dried, and weighed. The conversion rate and coking rate were calculated.

[0042] For comparison, the results of the hydrodeoxyisomerization of methyl palmitate were also measured without any catalyst and with molybdenum isooctanoate developed by Eni in Italy as a catalyst.

[0043] The results are shown in Table 1 below. The one-step hydrodeoxygenation isomeric supported bifunctional catalyst provided by this invention exhibits excellent catalytic activity. When applied to the suspension-bed hydrodeoxygenation isomerication of methyl palmitate, the conversion rate of methyl palmitate is significantly higher than that without a catalyst, and the coking rate is significantly lower than that without a catalyst. Compared with the molybdenum isooctanoate developed by Eni in Italy, the one-step hydrodeoxygenation isomeric supported bifunctional catalyst provided by this invention has essentially the same activity, but the preparation process is simpler and the reagents used are non-toxic, resulting in a significant cost advantage.

[0044] Table 1 Results of hydrodeoxyisomerization of methyl palmitate

[0045] Example 2 Example 3 Example 4 Example 6 Comparative Example 1 Comparative Example 2 catalyst B C D F none Molybdenum isooctanoate Cracking reaction temperature (°C) 400 400 400 400 400 400 Pressure (MPa) 20 20 20 20 20 20 Mo equivalent (ppm) 600 600 600 600 600 600 Conversion rate (%) 75.24 82.36 69.78 81.96 41.27 85.27 Coking rate (%) 3.58 1.86 4.79 1.26 30.37 3.58

[0046] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. The application of a supported bifunctional catalyst for one-step hydrodeoxyisomerization of bio-oils in the catalytic hydrodeoxyisomerization of bio-oils, characterized in that: Includes the following steps: S1: Add bio-oil to the suspension bed reactor, then add the bio-oil one-step hydrodeoxygenation isomeric supported bifunctional catalyst and sublimation sulfur powder in sequence. Seal the reactor and turn on the stirrer to fully mix the raw materials to obtain a mixture. S2: Replace the air and hydrogen in the reactor containing the mixture, and fill it with hydrogen to a certain pressure. Start the heating program at a heating rate of 4~6℃ / min. First, heat to the sulfidation temperature to carry out the sulfidation reaction, and then heat to the cracking reaction temperature to carry out the cracking reaction. The preparation method of the one-step hydrodeoxygenation isomeric supported bifunctional catalyst of bio-oil includes the following steps: (1) Add tetraethyl silicate and organic solvent to a beaker and stir at room temperature for 30-60 min to obtain solution I; add ammonia and organic solvent to a beaker and stir at room temperature for 30-60 min to obtain solution II; add the obtained solution II to solution I while stirring at room temperature, and continue stirring to form a transparent sol after the addition is complete, and then let it stand at room temperature for 24-48 h, filter, wash the filter cake with deionized water, and then vacuum dry the filter cake for 12 h, grind it to obtain SiO2 support; (2) Add SiO2 support and phosphomolybdic acid to a beaker, add deionized water, stir and dissolve at room temperature for 1-4 hours, rotary evaporate until the water evaporates, and vacuum dry for 12-24 hours to obtain a one-step hydrodeoxygenation isomer supported bifunctional catalyst for bio-oil.

2. The application according to claim 1, characterized in that: The bio-oil is any one of methyl palmitate, waste oil, or palm oil.

3. The application according to claim 1, characterized in that: In step S1, the mass ratio of the bio-oil and the bio-oil one-step hydrodeoxygenation isomeric supported bifunctional catalyst is 100:1~10; the S / Mo atomic ratio of the bio-oil one-step hydrodeoxygenation isomeric supported bifunctional catalyst and sublimed sulfur powder is 8~12:

1.

4. The application according to claim 1, characterized in that: In step S2, the pressure is 6~20MPa; the sulfidation temperature is 200~300℃; the sulfidation reaction time is 40~60min; the cracking reaction temperature is 350~450℃; and the cracking reaction time is 3~6h.

5. The application according to claim 1, characterized in that: In step (1), the volume ratio of tetraethyl silicate to organic solvent in solution I is 3:40; the volume ratio of ammonia to organic solvent in solution II is 1:20; the volume ratio of tetraethyl silicate to ammonia in the transparent sol is 3:2; the organic solvent is selected from any one of ethanol, acetone, and isopropanol; the concentration of ammonia is 25 vol%; and the vacuum drying temperature is 50~70℃.

6. The application according to claim 1, characterized in that: In step (2), the molar ratio of SiO2 support to phosphomolybdic acid is 1:0.01~0.2; the temperature of rotary evaporation is 80℃; and the temperature of vacuum drying is 150~250℃.