Method for preparing biodiesel by directionally regulating and controlling hydrodeoxygenation of biolipid

Abstract

The invention discloses a method for preparing biodiesel by directionally regulating and controlling hydrodeoxygenation of biological oil and fat, which belongs to the technical field of biodiesel preparation and comprises the following steps: dissolving the biological oil and fat in a solvent, mixing with hydrogen, injecting into a fixed bed reactor, and carrying out hydrodeoxygenation reaction by adopting an atom-substituted zirconium oxide loaded Ni catalyst to obtain the biodiesel. By changing elements doped in a carrier in the atom-substituted zirconium oxide-loaded Ni catalyst, the biological oil is controlled to directionally generate alkane with corresponding carbon number or alkane with one less carbon atom, and the biodiesel is obtained; the chemical formula of the atom-substituted zirconium oxide loaded Ni catalyst is Ni / xMZrO2, x is the molar percentage of M in a carrier, and M is one or two of Ce and Ti. According to the method, the carrier of the Ni / ZrO2 catalyst is subjected to functionalization treatment by using the auxiliaries Ce and Ti, the chemical property of the catalyst is regulated and controlled, the hydrogenation activity of the biological oil and fat and the selectivity of the product are controllably regulated, the selectivity of the target alkane component is improved, and the high-quality biodiesel is obtained.

Description

Technical Field

[0001] The invention relates to the technical field of biodiesel preparation, and in particular to a method for directional regulation of bio-oil hydrodeoxygenation to prepare biodiesel. Background Art

[0002] In recent years, bio-oil has replaced traditional fossil fuels with its renewable, clean and abundant advantages to provide energy for the application process of various industries. However, the constituent molecules of bio-oil contain a large number of oxygen atoms, and direct use as fuel has the disadvantages of poor stability, low calorific value and high viscosity. Therefore, it is necessary to remove oxygen atoms through hydrodeoxygenation treatment of bio-oil to improve the quality of oil products and obtain high calorific value and clean biodiesel. Therefore, finding efficient and stable catalysts has become the key to vigorously develop bio-oil to prepare clean energy.

[0003] At present, the commonly used bio-oil hydrodeoxygenation catalysts are mainly divided into precious metal catalysts and metal sulfide catalysts, but the high price of precious metal catalysts limits their large-scale application, while metal sulfides cause reduced activity and pollution due to the loss of sulfur during the reaction. The invention patent with publication number CN117797832A discloses a preparation method of a multi-metal sulfide hydrodeoxygenation catalyst, which is applied to the hydrogenation of waste oil to prepare biodiesel. Although this method shows a high deoxygenation rate and alkane yield, the preparation process of the catalyst is relatively complicated, and the use of sulfur powder in situ sulfurization will cause product pollution. Therefore, the development and application of clean non-precious metal-based catalysts have attracted much attention.

[0004] There are two main pathways for the hydrodeoxygenation of bio-oils. One is the direct hydrodeoxygenation pathway (HDO), which removes oxygen atoms in the form of H2O and generates alkanes with the corresponding number of carbon atoms. The direct hydrodeoxygenation process does not remove carbon, and the atom economy is higher, but it will inevitably generate water, which is easy to damage the structure of the catalyst and cause an irreversible decrease in catalytic activity. Therefore, there will be higher requirements for the water resistance of the catalyst; the other is the hydrodecarboxylation / decarbonylation pathway (DCO), which removes oxygen atoms in the form of CO / CO2 to generate alkanes with one less carbon atom. Although hydrodecarboxylation / decarbonylation only produces a trace amount of water, or even no water, CO2 / CO will be generated during the reaction, resulting in a certain amount of carbon loss.

[0005] The invention patent with the publication number CN111715229A discloses a method for preparing biofuel by hydrodeoxygenation of methyl laurate catalyzed by a sulfur-free nickel-based catalyst Ni / CeO2-TiO2. Under the conditions of a mass ratio of methyl laurate to catalyst of 10, a reaction temperature of 300°C, a hydrogen pressure of 2.5MPa, and a reaction time of 4h, a biofuel product mass yield of 96% can be obtained, and the product contains 98% of n-undecane by mass. In this process, the product obtained by using the catalyst is mainly n-undecane, but this does not meet the requirements of atom economy. How to controllably adjust the directional selectivity of direct hydrodeoxygenation and hydrodecarboxylation / decarbonylation of bio-oil catalysis according to the design and modification of the catalyst is a problem that needs to be solved.

[0006] In summary, there is still a lot of room for research in the existing research on the preparation of biodiesel by hydrodeoxygenation of bio-oils. In combination with the current research status, this patent proposes a method for directional regulation of the preparation of biodiesel by hydrodeoxygenation of bio-oils. Summary of the invention

[0007] The purpose of the present invention is to provide a method for directional regulation of bio-oil hydrodeoxygenation to prepare biodiesel, so as to solve the problems in the background technology.

[0008] To achieve the above object, the present invention provides a method for directional regulation of bio-oil hydrodeoxygenation to prepare biodiesel, comprising the following steps: The bio-oil is dissolved in a solvent to obtain a mixed solution with a mass concentration of 1.0-20%, the mixed solution is mixed with hydrogen and then injected into a fixed bed reactor, and a hydrogenation deoxygenation reaction is carried out using an atomic substituted zirconia supported Ni catalyst, and the coordination structure between the carrier and the heteroatom in the atomic substituted zirconia supported Ni catalyst is changed to control the bio-oil to generate alkanes with corresponding carbon numbers or alkanes with one less carbon atom, thereby obtaining biodiesel; The chemical formula of the atomic substituted zirconium oxide supported Ni catalyst is Ni / xMZrO2, x is the molar percentage of M in the carrier, and the value is 1-20%; M is one or two of Ce and Ti, and the Ni loading is 5-50wt.%; Atom-substituted zirconium oxide-loaded Ni catalyst is used as the catalyst for the hydrodeoxygenation of bio-oil to prepare biodiesel. The heteroatom M replaces the original Zr atom in the ZrO2 crystal structure to form a MO-Zr coordination structure that accurately adjusts the electronic state and chemical properties of the ZrO2 carrier itself, thereby controlling the bio-oil to directional generate alkanes with the same carbon number or alkanes with one less carbon atom.

[0009] Preferably, the preparation steps of the atomic substituted zirconium oxide supported Ni catalyst are: 1) dissolving one or two of zirconium salt, cerium salt or titanium salt in deionized water to obtain a metal precursor salt solution, then adding urea and stirring until dissolved to obtain a mixed solution; heating the mixed solution in a reactor, filtering to obtain a precipitate, washing and drying, and then calcining in an O2 / Ar mixed atmosphere to obtain an atomic substituted zirconium oxide carrier; 2) The obtained atomic substituted zirconia carrier and nickel salt are added to deionized water, stirred evenly, rotary evaporated, dried, and then calcined in an O2 / Ar mixed atmosphere to obtain an atomic substituted zirconia supported Ni-based catalyst.

[0010] Preferably, in the specific preparation step 1) of the atomic substituted zirconia carrier, the molar ratio of urea to metal precursor salt solution is 10:1, the heating temperature in the reactor is 120-180°C, the heating time is 10-20h, the calcination temperature is 500-650°C, and the calcination time is 3-5h.

[0011] Preferably, in step 2) of preparing the atomic substituted zirconium oxide supported Ni catalyst, the stirring time is 8 to 12 hours, the calcination temperature is 340 to 450° C., and the calcination time is 3 to 5 hours.

[0012] Preferably, the bio-oil is one or more of palm oil, soybean oil and rapeseed oil.

[0013] Preferably, the solvent is one or more of n-decane, cyclohexane and n-heptane.

[0014] Preferably, before the hydrodeoxygenation reaction, the atomic substituted zirconium oxide supported Ni catalyst is in situ reduced in a fixed bed reactor for 1.5 to 2.5 hours at a reduction temperature of 300 to 400°C.

[0015] Preferably, during the hydrodeoxygenation reaction, the concentration of bio-oil is 1.0-20wt.%, the temperature is 160-300°C, the hydrogen pressure is 0.2-4MPa, and the mass space velocity is 0.2-4.8h -1 , the ratio of hydrogen to bio-oil is 200~800:1.

[0016] Therefore, the method for preparing biodiesel by directional regulation of bio-oil hydrodeoxygenation of the present invention has the following beneficial effects: (1) The present invention functionalizes the carrier of the Ni / ZrO2 catalyst by using additives Ce and Ti to regulate the chemical properties of the catalyst, thereby achieving controllable regulation of the hydrogenation activity and product selectivity of bio-oils, improving the selectivity of the target alkane component, and obtaining high-quality biodiesel. At the same time, it provides a method for the design of catalysts for selective conversion in the bio-oil hydrogenation and deoxygenation system, especially for product selection, and has many advantages such as cleanliness, high reserves, and low cost.

[0017] (2) In the present invention, Ce atoms replace Zr atoms and are inserted into ZrO2 to form Ce-O-Zr bonds. Since the electronegativity of Ce (1.12) is lower than that of Zr (1.4), the electrons in the Ce-O-Zr bond are attracted by Zr, so that more electrons are enriched around Zr. According to the acid-base proton theory, the electron enrichment on the catalyst surface will form Lewis acid sites, which is directly beneficial to the adsorption of oxygen-containing groups in biological oils and fats. On the other hand, the electronic effect of the Zr-O-Ni interface effectively improves the catalyst's hydrogenation and CC bond cleavage capabilities, making it have higher activity and decarboxylation selectivity.

[0018] When Ti atoms replace Zr atoms and are inserted into ZrO2, Ti-O-Zr bonds will be formed. The difference is that the electronegativity of Ti (1.54) is higher than that of Zr (1.4). Therefore, the area around Zr in the Ti-O-Zr bond is in an electron-deficient state, which directly increases the hydroxyl content on the surface of the ZrO2 carrier. The hydroxyl groups on the catalyst surface can serve as Bronsted acid sites, improving the catalyst's ability to break CO / C=O and obtaining a higher direct hydrogenation and deoxygenation selectivity.

[0019] The Ni catalyst loaded on the ternary atom-substituted carrier composed of Ce, Ti and Zr can achieve the modulation of the electronic state and acidity of the ZrO2 carrier itself by changing the ratio of Ce and Ti, thereby achieving directional regulation of the hydrogenation activity and target products.

[0020] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 X-ray diffraction patterns of the catalyst Ni / ZrO2 of Comparative Example 1, the catalyst Ni / 5CeZrO2 of Example 3, and the catalyst Ni / 10TiZrO2 of Example 7 in the present invention; Figure 2 TEM characterization images of the catalyst Ni / ZrO2 of Comparative Example 1, the catalyst Ni / 5CeZrO2 of Example 3, and the catalyst Ni / 10TiZrO2 of Example 7 in the present invention, wherein a is Ni / 10TiZrO2, b is Ni / ZrO2, and c is Ni / 5CeZrO2; Figure 3 It is the XPS Zr 3d spectra of the catalyst Ni / ZrO2 of Comparative Example 1, the catalyst Ni / 5CeZrO2 of Example 3 and the catalyst Ni / 10TiZrO2 of Example 7 in the present invention. DETAILED DESCRIPTION

[0022] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0023] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0024] Example 1 The Ni / 1CeZrO2 catalyst was prepared as follows: 1) Mix ZrO(NO3)2·xH2O and Ce(NO3)3·6H2O and dissolve them in deionized water, with the addition amount of Ce(NO3)3·6H2O being 1 mol.%; to obtain a metal precursor salt solution with a concentration of 0.4 mol / L; add 16.817 g of urea to the metal precursor salt solution, stir thoroughly until completely dissolved, and obtain a mixed solution.

[0025] Then, the obtained mixed solution was transferred to a 100 mL reactor and heated at 150°C for 12 h. After filtering and washing, the powder sample was dried at 100°C overnight and calcined at 600°C in an O2 / Ar mixed atmosphere for 4 h to obtain a 1CeZrO2 carrier.

[0026] 2) Add 1g 1CeZrO2 carrier and 1.23g Ni(NO3)2·6H2O into a certain amount of deionized water, stir for 10h, and then evaporate and dry at 100℃ overnight, and then calcine at 400℃ in an O2 / Ar mixed atmosphere for 4h to obtain Ni / 1CeZrO2 catalyst.

[0027] Example 2 The Ni / 3CeZrO2 catalyst was prepared in the same steps as in Example 1, except that the amount of Ce added was changed to 3 mol%.

[0028] Example 3 The Ni / 5CeZrO2 catalyst was prepared in the same steps as in Example 1, except that the amount of Ce added was changed to 5 mol%.

[0029] Example 4 The Ni / 10CeZrO2 catalyst was prepared in the same steps as in Example 1, except that the amount of Ce added was changed to 10 mol%.

[0030] Example 5 The Ni / 1TiZrO2 catalyst was prepared in the same steps as in Example 1, with the only difference being that Ce(NO3)3·6H2O was replaced with Ti(SO4)2.

[0031] Example 6 The Ni / 5TiZrO2 catalyst was prepared in the same steps as in Example 1, except that the amount of Ti added was changed to 5 mol%.

[0032] Example 7 The Ni / 10TiZrO2 catalyst was prepared in the same steps as in Example 1, except that the amount of Ti added was changed to 10 mol%.

[0033] Example 8 The Ni / 15TiZrO2 catalyst was prepared in the same steps as in Example 1, except that the amount of Ti added was changed to 15 mol%.

[0034] Example 9 The Ni / 3Ce7TiZrO2 catalyst was prepared in the same steps as in Example 1, except that ZrO(NO3)2·xH2O was mixed with 3 mol.% Ce(NO3)3·6H2O and 7 mol.% Ti(SO4)2 and dissolved in deionized water.

[0035] Example 10 The Ni / 5Ce5TiZrO2 catalyst was prepared in the same steps as in Example 1, except that ZrO(NO3)2·xH2O was mixed with 5 mol.% Ce(NO3)3·6H2O and 5 mol.% Ti(SO4)2 and dissolved in deionized water.

[0036] Embodiment 11 The Ni / 7Ce3TiZrO2 catalyst was prepared in the same steps as in Example 1, except that ZrO(NO3)2·xH2O was mixed with 7 mol.% Ce(NO3)3·6H2O and 3 mol.% Ti(SO4)2 and dissolved in deionized water.

[0037] Comparative Example 1 The Ni / ZrO2 catalyst was prepared in the same steps as in Example 1, except that Ce(NO3)3·6H2O was not added.

[0038] The catalyst of Comparative Example 1 and the catalysts of Example 3 and Example 7 were tested. Figure 1 As shown in the figure, by comparing the XRD patterns of the three catalysts, it can be found that after the introduction of Ce and Ti, no diffraction peaks belonging to CeO2 and TiO2 were observed, but the phase structure of the ZrO2 carrier changed and shifted, indicating that Ce 4+ and Ti 4+ Replaced Zr 4+ , successfully inserted into the ZrO2 lattice, forming Ce-O-Zr and Ti-O-Zr coordination structures, rather than a mixed oxide.

[0039] like Figure 2 As shown in the figure, by comparing the TEM characterization images of the three catalysts, lattice fringes (0.203 nm) of the Ni (111) plane were observed near ZrO2 of the three catalysts, indicating that a Ni-O-Zr interface was formed between Ni and ZrO2. In addition, it was observed that the lattice spacing (0.316 nm) belonging to the m-ZrO2 (-111) plane in the Ni / 5CeZrO2 catalyst was reduced to 0.307 nm, and the lattice spacing (0.295 nm) belonging to the t-ZrO2 (101) crystal plane in the Ni / 10TiZrO2 catalyst was slightly shrunk compared with the lattice spacing (0.295 nm) in the standard card. Therefore, it is shown that Ce and Ti are inserted into the ZrO2 lattice to replace Zr atoms to form Ni / ZrO2 with Ce-O-Zr and Ti-O-Zr coordination structures, and it is not a simple mixture of two oxides.

[0040] like Figure 3 As shown in the figure, comparing the spectra of the three catalysts, the Zr 3d spectrum shows two different peaks at 181.8 and 184.1 eV, corresponding to Zr 3+ Species 3D 5 / 2 and 3D 3 / 2 orbital. After adding Ce, Zr 3+ The binding energy of the species is reduced, and after adding Ti, Zr 3+ The binding energy of the species increases. This is because the electronegativity of Ce (1.12) is lower than that of Zr (1.4), while the electronegativity of Ti (1.54) is higher than that of Zr (1.4). Therefore, the electrons in the formed Ce-O-Zr bond are attracted to Zr, while the electrons around Zr in the Ti-O-Zr bond are dispersed, which in turn changes the electronic state of ZrO2 itself, and Zr 3+ and Zr 4+ This is also evidenced by the species content.

[0041] Comparative Example 2 The steps for preparing Ni / 5CeO2-ZrO2 catalyst are as follows: 1) Prepare a solution with a concentration of 0.4 mol / L of ZrO(NO3)2·xH2O, add 16.817g of urea, stir thoroughly until completely dissolved, and obtain a mixed solution; transfer the obtained mixed solution to a 100mL reactor, heat at 150℃ for 12h, filter and dry the obtained powder sample at 100℃ overnight. Then, take the dried powder and dissolve it in deionized water, add 5mol.% Ce(NO3)3·6H2O, stir thoroughly for 6h, evaporate the liquid, dry the obtained powder at 100℃ overnight, and calcine at 600℃ in an O2 / Ar mixed atmosphere for 4h to obtain a 5CeO2-ZrO2 carrier.

[0042] 2) Add 1 g of 5CeO2-ZrO2 carrier and 1.2 g of Ni(NO3)2·6H2O into a certain amount of deionized water, stir for 10 h, and then rotary evaporate and dry at 100°C overnight, and then calcine at 400°C in an O2 / Ar mixed atmosphere for 4 h to obtain a Ni / 5CeO2-ZrO2 catalyst.

[0043] Comparative Example 3 The Ni / 10TiO2-ZrO2 catalyst was prepared by the same specific steps as in Comparative Example 2, except that Ce(NO3)3·6H2O was replaced with Ti(SO4)2 in an amount of 10 mol.%.

[0044] The catalysts prepared in Examples 1-11 and Comparative Examples 1-3 were applied to the directional regulation of bio-oil hydrodeoxygenation to produce biodiesel, and the specific steps were as follows: A fixed bed reactor was selected to dissolve palm oil in n-decane to obtain a palm oil solution with a mass concentration of 10 wt.%. The palm oil solution with a hydrogen-to-oil ratio of 300:1 was mixed with hydrogen and injected into a fixed bed device equipped with an atomic substituted zirconium oxide supported Ni catalyst for hydrodeoxygenation reaction. The catalyst amount was 0.5 g, the reaction pressure was 0.2 MPa, the reaction temperature was 240 °C, and the mass space velocity was 2 h -1 , catalyzing the hydrodeoxygenation of bio-oil to produce biodiesel.

[0045] The specific reaction results are as follows: Table 1 Comparison of catalytic performance of catalysts in different examples

[0046] As can be seen from the table above, by using Ni / ZrO2 supported catalyst, Ce atoms and Ti atoms are introduced into the ZrO2 lattice to replace Zr atoms to form corresponding Ce-O-Zr and Ti-O-Zr bonds, thereby adjusting the electronic state and chemical properties of the ZrO2 carrier itself through the bond bridge, and then the Ni / ZrO2 catalyst is modified in a directional manner, achieving controllable regulation of the bio-oil hydrodeoxygenation activity and product selectivity. In the process of catalyzing the hydrodeoxygenation of bio-oil to produce biodiesel, the electron migration of Ce to Zr in the Ce-O-Zr bond enriches more electrons around Zr, which is beneficial to the adsorption of oxygen-containing groups in bio-oils on the one hand, and on the other hand, the electronic effect of the Zr-O-Ni interface promotes the electron rearrangement of the Ni site to Ni 0, enhancing the dissociation of H2 and the breaking of CC bonds, thereby improving the hydrodeoxygenation activity and decarboxylation (DCO) selectivity. The enrichment of electrons around Zr by Ti in the Ti-O-Zr bond increases the hydroxyl content on the surface of the ZrO2 carrier, thereby enriching the Brønsted acid sites on the catalyst surface, promoting the breaking of CO / C=O, and thus improving the direct hydrodeoxygenation (HDO) selectivity. In contrast, Ni / 5CeO2-ZrO2 and Ni / 10TiO2-ZrO2 catalysts with simple composite oxides as carriers cannot form corresponding bonds, so it is impossible to achieve directional regulation of bio-oil hydrodeoxygenation activity and product selectivity.

[0047] Therefore, the present invention provides a method for preparing biodiesel by directional regulation of bio-oil hydrodeoxygenation, by functionalizing the carrier of Ni / ZrO2 catalyst with additives Ce and Ti, regulating the chemical properties of the catalyst, achieving controllable regulation of bio-oil hydrogenation activity and product selectivity, improving the selectivity of target alkane components, and obtaining high-quality biodiesel. At the same time, it provides a method for designing catalysts for selective conversion in the bio-oil hydrodeoxygenation system, especially for product selection, and has many advantages such as cleanliness, high reserves, and low cost.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for directional regulation of bio-oil hydrodeoxygenation to prepare biodiesel, characterized in that: The following steps are involved: The bio-oil is dissolved in a solvent to obtain a mixed solution with a mass concentration of 1.0-20%, the mixed solution is mixed with hydrogen and then injected into a fixed bed reactor, and a hydrogenation deoxygenation reaction is carried out using an atomic substituted zirconia supported Ni catalyst, and the coordination structure between the carrier and the heteroatom in the atomic substituted zirconia supported Ni catalyst is changed to control the bio-oil to generate alkanes with corresponding carbon numbers or alkanes with one less carbon atom, thereby obtaining biodiesel; The chemical formula of the atomic substituted zirconia supported Ni catalyst is Ni / xMZrO2, where x is the molar percentage of M in the carrier, and the value is 1-20%; M is one or two of Ce and Ti, and the Ni loading amount is 5-50wt.%.

2. The method for preparing biodiesel by directional regulation of bio-oil hydrodeoxygenation according to claim 1, characterized in that: The preparation steps of the atomic substituted zirconium oxide supported Ni catalyst are: 1) dissolving one or two of zirconium salt, cerium salt or titanium salt in deionized water to obtain a metal precursor salt solution, then adding urea and stirring until dissolved to obtain a mixed solution; heating the mixed solution in a reactor, filtering to obtain a precipitate, washing and drying, and then calcining in an O2 / Ar mixed atmosphere to obtain an atomic substituted zirconium oxide carrier; 2) The obtained atomic substituted zirconia carrier and nickel salt are added to deionized water, stirred evenly, rotary evaporated, dried, and then calcined in an O2 / Ar mixed atmosphere to obtain an atomic substituted zirconia supported Ni-based catalyst.

3. The method for preparing biodiesel by directional regulation of bio-oil hydrodeoxygenation according to claim 2, characterized in that: In the specific preparation step 1) of the atomic substituted zirconium oxide carrier, the molar ratio of urea to metal precursor salt solution is 10:1, the heating temperature in the reactor is 120-180°C, the heating time is 10-20h, the calcination temperature is 500-650°C, and the calcination time is 3-5h.

4. The method for preparing biodiesel by directional regulation of bio-oil hydrodeoxygenation according to claim 1, characterized in that: The biological oil is one or more of palm oil, soybean oil and rapeseed oil.

5. The method for preparing biodiesel by directional regulation of bio-oil hydrodeoxygenation according to claim 1, characterized in that: The solvent is one or more of n-decane, cyclohexane and n-heptane.

6. The method for preparing biodiesel by directional regulation of bio-oil hydrodeoxygenation according to claim 1, characterized in that: Before the hydrodeoxygenation reaction, the atomic substituted zirconium oxide supported Ni catalyst is in situ reduced in a fixed bed reactor for 1.5 to 2.5 hours at a reduction temperature of 300 to 400°C.

7. The method for preparing biodiesel by directional regulation of bio-oil hydrodeoxygenation according to claim 1, characterized in that: During the hydrodeoxygenation reaction, the concentration of bio-oil is 1.0-20wt.%, the temperature is 160-300°C, the hydrogen pressure is 0.2-4MPa, and the mass space velocity is 0.2-4.8h -1 , the ratio of hydrogen to bio-oil is 200~800:1.

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