CN113444541B

CN113444541B - Biodiesel component oil and preparation method thereof

Info

Publication number: CN113444541B
Application number: CN202010216050.9A
Authority: CN
Inventors: 闫瑞; 赵红; 杜泽学
Original assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Current assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Priority date: 2020-03-25
Filing date: 2020-03-25
Publication date: 2022-10-21
Anticipated expiration: 2040-03-25
Also published as: CN113444541A

Abstract

The invention provides a biodiesel component oil and a preparation method thereof, wherein the preparation method comprises the following steps: subjecting lignocellulose-based furfural compound and carbonyl compound to aldol condensation reaction to obtain C ₈ ～C ₁₆ A long chain oxygen-containing compound; to C ₈ ～C ₁₆ Carrying out hydrogenation saturation on the long-chain oxygen-containing compound; and hydrodeoxygenating the hydrogenation saturated product, and fractionating the hydrodeoxygenated product to obtain the biodiesel component oil. The method can realize catalytic conversion based on the biomass sugar platform compound to prepare the biodiesel component oil, is beneficial to comprehensive utilization of agricultural and forestry wastes, and realizes green sustainable development.

Description

Biodiesel component oil and preparation method thereof

Technical Field

The invention relates to the technical field of petrochemical industry, and particularly relates to biodiesel component oil and a preparation method thereof.

Background

Under the background of increasingly severe petroleum crisis and greenhouse effect, biomass, which is the only renewable energy source containing carbon sources, is the most promising resource for preparing hydrocarbon liquid fuels to replace petroleum at present. In order to continue the transition from fossil energy economy to carbohydrate economy and convert biomass into fuels and chemicals with high added values, dumesic working team uses lignocellulose hydrolysate furfural as raw material, and furfurylideneacetone [4- (2-furyl) -3-buten-2-one is obtained by first extending the carbon chain through aldol condensation reaction]And difurfurylideneacetone [1, 5-bis- (2-furyl) -1, 4-pentadien-3-one]Then hydrodeoxygenation to C ₈ Straight chain alkane and C ₁₃ Straight-chain paraffin, and finally obtaining qualified product through isomerizationThe jet fuel component of (1) achieves high-efficiency utilization of biomass (science, 2005,308, 1446-1450). As shown in formula I below:

however, since the difurfurylideneacetone generated by the condensation of furfural and acetone is solid, the direct entering of the reactor into a tubular reactor for continuous treatment is difficult. On the other hand, furfurylideneacetone, difurfurylideneacetone, and the like have a large conjugated structure with a furan ring and a C = C double bond, are unstable at high temperatures, and are liable to cause side reactions such as self-polymerization. In addition, hydrodeoxygenation (HDO) reactions, which allow higher calorific values and chemical stability of the lignocellulosic hydrolysates, are key steps in the preparation of liquid hydrocarbon fuels. However, the existing reports aiming at preparing liquid hydrocarbon fuel by catalyzing sugar platform compounds are not many, and most of the reports are direct hydrodeoxygenation conversion, and the mode has the problems of more side reactions, easy carbon deposition and inactivation of catalysts and the like.

It is noted that the information disclosed in the foregoing background section is only for enhancement of background understanding of the invention and therefore it may contain information that does not constitute prior art that is already known to a person of ordinary skill in the art.

Disclosure of Invention

The invention aims to overcome at least one defect of the prior art and provides biodiesel component oil and a preparation method thereof, so as to solve the problems of more side reactions, easy inactivation of a catalyst and the like in the process of preparing hydrocarbon fuel by using the existing sugar platform compounds.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention provides a preparation method of biodiesel component oil, which comprises the following steps: subjecting lignocellulose-based furfural compound and carbonyl compound to aldol condensation reaction to obtain C ₈ ～C ₁₆ A long chain oxygen-containing compound; to C ₈ ～C ₁₆ Carrying out hydrogenation saturation on the long-chain oxygen-containing compound; and hydrodeoxygenating the hydrodesaturated product, and fractionating the hydrodeoxygenated product to obtain the biodieselAnd (3) component oil.

According to one embodiment of the invention, the lignocellulose-based furfural compound is selected from one or more of furfural and 5-hydroxymethyl furfural, the carbonyl compound is an alpha-H carbonyl compound, the alpha-H carbonyl compound is selected from one or more of acetone and levulinic acid, and the molar ratio of the lignocellulose-based furfural compound to the carbonyl compound is 1.

According to one embodiment of the invention, the aldol condensation reaction is carried out under the action of a base catalyst, the base catalyst is an inorganic base, the inorganic base is one or more selected from sodium hydroxide, potassium hydroxide, ammonia water, sodium carbonate and potassium carbonate, and the molar concentration of the inorganic base is 0.05 mol/L-1 mol/L.

According to one embodiment of the invention, the hydrosaturation is carried out over a hydrosaturation catalyst comprising a composite of nickel and silica, wherein the silica is in an amorphous structure and the nickel is in a crystalline structure.

According to one embodiment of the invention, the compound has the formula Ni- (SiO) ₂ ) _a And a has a value of 0.1 to 40.

According to one embodiment of the invention, the hydrosaturation comprises: c is to be ₈ ～C ₁₆ Dissolving long-chain oxygen-containing compound in organic solvent, and performing hydrogenation saturation reaction on the obtained solution in a fixed bed reactor containing hydrogenation saturation catalyst, wherein the organic solvent is oxygen-containing solvent selected from one or more of methanol, ethanol and acetone, and C in the solution ₈ ～C ₁₆ The mass percentage of the long-chain oxygen-containing compound is 0.5-50%.

According to one embodiment of the invention, the hydrogenation saturation reaction temperature is 0-200 ℃, the reaction pressure is 0.5-15 MPa, and the mass space velocity is 0.1h ^-1 ～10h ^-1 The volume ratio of hydrogen to oil is 50-3000.

According to one embodiment of the invention, the hydrodeoxygenation is carried out over a hydrodeoxygenation catalyst, the hydrodeoxygenation catalyst comprises a first carrier and a first active metal loaded on the first carrier, wherein the first active metal is selected from nickel, molybdenum, tungsten, cobalt,One or more of palladium and platinum, and the first carrier is M- (SiO) ₂ ) _X The composite oxide, M is selected from one or more of niobium oxide, cobalt oxide and cerium oxide, and x is 1-100.

According to one embodiment of the invention, M is Nb in an amorphous structure ₂ O ₅ X is 1 to 40; the first active metal is selected from one or more of palladium, nickel and platinum, and the loading amount of the first active metal is 0.05wt% -30 wt%.

According to one embodiment of the invention, the first support is made of M and SiO ₂ Porous structure of aggregated oxide particle clusters, siO ₂ The carrier is an amorphous structure, the size of the cluster is 200 nm-2000 nm, and the specific surface area of the first carrier is 200m ² /g～700m ² (iv)/g, pore volume is 0.1cc/g to 0.9cc/g.

According to one embodiment of the invention, hydrodeoxygenation comprises: the hydrogenation saturated product is subjected to hydrogenation deoxidation reaction in a fixed bed reactor containing a hydrogenation deoxidation catalyst, wherein the reaction temperature is 100-400 ℃, the reaction pressure is 0.5-15 MPa, and the mass space velocity is 0.1h ^-1 ～10h ^-1 The volume ratio of hydrogen to oil is 50-3000.

The invention also provides biodiesel component oil prepared by the method.

According to the technical scheme, the invention has the beneficial effects that:

according to the preparation method of the biodiesel component oil, provided by the invention, through designing a synthesis route, the condensation product is subjected to hydrogenation saturation treatment before being subjected to hydrodeoxygenation, and a proper specific catalyst is adopted in each step, so that the whole reaction process has few side reactions, and the conversion rate and the yield are high, and the preparation method has a good application prospect. The method can realize catalytic conversion based on the biomass sugar platform compound to prepare the biodiesel component oil, is beneficial to comprehensive utilization of agricultural and forestry wastes, and realizes green sustainable development.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention.

FIG. 1 is a flow diagram of a process for the preparation of a biodiesel component oil in accordance with one embodiment of the present invention;

FIG. 2 is an XRD spectrum of a hydrogenation saturation catalyst in preparation example 1;

FIG. 3 is an XRD spectrum of the hydrodeoxygenation catalyst of preparation 2;

FIG. 4 is a C-NMR spectrum of a condensation product of example 1;

FIG. 5 is an H-NMR spectrum of a condensation product of example 1;

FIG. 6 is an IR spectrum of the condensation product of example 1;

FIG. 7 is a process flow diagram of a hydrosaturation reaction in accordance with one embodiment of the present invention;

FIG. 8 is a process flow diagram of a hydrodeoxygenation reaction according to one embodiment of the present invention;

FIG. 9 is the MS spectrum of the hydrodeoxygenation product tridecane of example 21;

FIG. 10 is a dodecane MS spectrum of the hydrodeoxygenation product of example 21;

FIG. 11 is the undecane MS spectrum of the hydrodeoxygenation product of example 21.

Detailed Description

The following presents various embodiments or examples in order to enable those skilled in the art to practice the invention with reference to the description herein. These are, of course, merely examples and are not intended to limit the invention. The endpoints of the ranges and any values disclosed in the present application are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to yield one or more new ranges of values, which ranges of values should be considered as specifically disclosed herein.

Fig. 1 is a flow chart of a process for preparing a biodiesel component oil according to an embodiment of the present invention. As shown in figure 1, the preparation method of the biodiesel component oil comprises the following steps:

s1: subjecting lignocellulose-based furfural compound and carbonyl compound to aldol condensation reaction to obtain C ₈ ～C ₁₆ A long chain oxygen-containing compound;

s2: to C ₈ ～C ₁₆ Carrying out hydrogenation saturation on the long-chain oxygen-containing compound;

s3: and (3) carrying out hydrodeoxygenation on the hydrogenation saturated product, and fractionating the hydrodeoxygenated product to obtain the biodiesel component oil.

According to the invention, the problems of more side reactions, easy inactivation of the catalyst and the like still exist in the process of preparing the hydrocarbon fuel by using the existing sugar platform compounds. According to the invention, a synthesis route is redesigned, firstly, a bio-friendly sugar platform compound is selected to perform carbon chain regulation through an aldol condensation reaction to obtain a proper long-chain oxygen-containing compound, then, the condensation product is subjected to hydrogenation saturation treatment to saturate double bonds of C = C and C = O and convert the double bonds into liquid dissolved in saturated alkane, and thus, the liquid can enter a continuous tubular reactor. Then, a specific catalyst is adopted to further carry out hydrodeoxygenation reaction so that oxygen atoms in the product can be removed in the form of water, thus the lignocellulose hydrolysate obtains higher calorific value and chemical stability, and finally the biodiesel component oil is obtained by fractionation. The whole process of the invention has reasonable design and less side reaction, and the adopted hydrogenation catalyst has the characteristics of high activity, high stability, good reusability and the like, further improves the reaction conversion rate and yield, and has good application prospect.

The method for producing the biodiesel component oil will be specifically described below.

In step S1, an aldol condensation reaction is performed on a lignocellulose-based furfural-based compound and a carbonyl compound using an alkali catalyst. The lignocellulose-based furfural compound is selected from one or more of furfural and 5-hydroxymethyl furfural, the carbonyl compound is an alpha-H carbonyl compound, and the alpha-H carbonyl compound is selected from one or more of acetone and levulinic acid. In some embodiments, the molar ratio of lignocellulose-based furfural-based compound to carbonyl compound is 1.

In some embodiments, the base catalyst is an inorganic base selected from one or more of sodium hydroxide, potassium hydroxide, ammonia, sodium carbonate and potassium carbonate, and the molar concentration of the inorganic base is 0.05mol/L to 1mol/L.

In the aldol condensation reaction, a batch reactor is generally used, and the reaction temperature is 0 ℃ to 100 ℃, for example, 0 ℃, 10 ℃, 25 ℃,40 ℃, 55 ℃, 70 ℃, 75 ℃, 80 ℃, 94 ℃, 100 ℃ and the like. The reaction time is 1h to 12h, such as 1h, 2h, 4h, 6h, 8h, 11h, 12h and the like; the reaction solvent is water, the molar concentration of the inorganic base in the reaction solution is 0.05mol/L to 1.00mol/L, such as 0.05mol/L, 0.15mol/L, 0.85mol/L, 0.13mol/L, 0.68mol/L, 0.93mol/L, 1mol/L and the like, and the mass fraction of the lignocellulose-based furfural-based compound in the reaction solution is 5% to 40%, such as 5%, 15%, 20%, 27%, 34%, 38%, 40% and the like. By selecting the above specific test conditions, especially by controlling the molar ratio of the raw materials, carbon chain regulation can be performed, thereby preparing C ₈ ～C ₁₆ Long chain oxygen-containing compounds.

In step S2, after the aldol condensation reaction is completed, the resultant C ₈ ～C ₁₆ And (4) hydrogenating and saturating the long-chain oxygen-containing compound. Taking the condensation reaction of furfural and acetone as an example, the generated difurfurylideneacetone is solid and is difficult to directly enter a tubular reactor for continuous treatment; further, for example: furfurylideneacetone, difurfurylideneacetone, and the like have a large conjugated structure with a furan ring and a C = C double bond, are unstable at high temperatures, and are prone to side reactions such as self-polymerization. Therefore, the hydrogenation pretreatment is firstly completed at a lower temperature, namely the hydrogenation saturation is carried out on the hydrogenation pretreatment, so that the side reaction in the subsequent hydrodeoxygenation process carried out at a higher temperature can be avoided; by simultaneously saturating the double bonds C = C and C = O, the solid product can be converted into a liquid dissolved in saturated alkane, and then can enter a continuous tubular reactor for subsequent reaction.

The hydrogenation saturation process mainly comprises the following steps: will C ₈ ～C ₁₆ Dissolving long-chain oxygen-containing compound in organic solvent, and placing the obtained solution in a fixed bed reactor containing hydrogenation saturated catalystAnd carrying out hydrogenation saturation reaction to obtain a hydrogenation saturated product. Wherein the organic solvent is selected from one or more of oxygen-containing solvents such as methanol, ethanol, and acetone, and in some embodiments, C in solution ₈ ～C ₁₆ The mass percentage of the long-chain oxygen-containing compound is 0.5% to 50%, for example, 0.5%, 1.7%, 3.8%, 12%, 24%, 32%, 40%, 47%, 50%, etc.

The hydrogenation saturation catalyst comprises a composite of nickel and silica, wherein the nickel is in a crystal structure, and the silica is in an amorphous structure. Specifically, the chemical formula of the compound is Ni- (SiO) ₂ ) _a The value of a is 0.1 to 40, for example, 2.1, 3, 3.2, 4.5, 5, 6.7, 6.8, 6.9, 7, 7.1, 10, 10.8, 11, 13.9, 14, etc. In some embodiments, preferably, a is 2.9 to 11.1. The structure of the composite is a porous structure formed by gathering nickel crystal grains and silicon dioxide oxide particle clusters, the particle clusters are distributed irregularly, the cluster size is 200 nm-500 nm, and the nickel crystal grain size is 0.5 nm-10 nm. The specific surface area of the hydrogenation saturation catalyst is 200m ² /g～500m ² A/g, preferably of 200m ² /g～380m ² G, e.g. 220m ² /g、240m ² /g、300m ² /g、320m ² (iv)/g, etc.; the pore volume is 0.2cc/g to 0.7cc/g, preferably 0.3cc/g to 0.6cc/g, for example, 0.37cc/g, 0.40cc/g, 0.42cc/g, 0.44cc/g, 0.45cc/g, etc. From the foregoing, it can be seen that the hydrogenation saturation catalyst has a specific porous cluster aggregation structure, which is beneficial to increasing the specific surface area of the catalyst in contact with reactants, and further improving the catalytic activity. In some embodiments, the hydrosaturation catalyst comprises nickel in an amount of 1wt% to 60wt% and silica in an amount of 40wt% to 99wt%. Preferably, the nickel content is 5wt% to 40wt%, and the silica content is 60wt% to 95wt%.

The hydrogenation saturation catalyst can be prepared by a precipitation method or a sol-gel method.

In some embodiments, the precipitation method comprises: adding alkali into the mixture of the nickel source and the silicon source for reaction to generate a precipitate; and drying, roasting and reducing the precipitate to obtain the hydrogenation saturation catalyst. Furthermore, the catalyst can be shaped during the preparation process of the hydrogenation saturation catalyst to improve the mechanical strength of the catalyst. Specifically, the method comprises the following steps: adding alkali into the mixture of the nickel source and the silicon source for reaction to generate a precipitate; drying the precipitate, adding an auxiliary agent, and carrying out molding treatment; and reducing the formed material to obtain the hydrogenation saturation catalyst. Wherein the forming process includes, but is not limited to, one or more of extruding, rolling, tabletting, and pelletizing.

In the process of precipitation reaction, firstly, the soluble nickel source and the soluble silicon source are mixed with water to prepare a mixed solution, then alkali liquor is added into the mixed solution, and the mixture is stirred to generate precipitate. Generally, the reaction temperature for generating the precipitate is 0-60 ℃, and the stirring time is 0-6 h, namely, the stirring can be carried out or not. Standing and aging for a period of time after the precipitate is generated, wherein the standing time is about 6-12 h, preferably 8-12 h; then, the precipitate after the standing aging is dried, and then, the molding treatment can be performed. The drying temperature is 100-130 ℃, and the drying time is 2-24 h. In some embodiments, the precipitate is dried and then further calcined, wherein the calcination temperature is 300-700 ℃ and the calcination time is 2-6 h. Then, reducing the roasted product at 400-600 ℃ for 2-6 h. And reducing to obtain a compound of crystalline nickel and amorphous silica, namely the hydrogenation saturation catalyst. By adopting the hydrogenation saturation catalyst, the preparation method is simple, pollution-free and low in cost, and the obtained catalyst is higher in activity and stability and easier to separate.

In some embodiments, the sol-gel process comprises: adding a hydrolytic agent and water into a mixture of a nickel source and a silicon source to carry out sol-gel reaction; and drying, roasting and reducing the obtained product after the sol-gel reaction to obtain the hydrogenation saturation catalyst. Furthermore, the catalyst can be shaped during the preparation process of the hydrogenation saturation catalyst to improve the mechanical strength of the catalyst. The method specifically comprises the following steps: adding a hydrolytic agent and water into a mixture of a nickel source and a silicon source to carry out sol-gel reaction; adding an auxiliary agent into the product after the sol-gel reaction, and carrying out molding treatment; and reducing the formed material to obtain the hydrogenation saturation catalyst. Wherein the forming process includes, but is not limited to, one or more of extruding, rolling, tabletting, and pelletizing.

In the sol-gel reaction process, firstly mixing a nickel source, a silicon source and water to prepare a mixed solution, then adding a hydrolytic agent into the mixed solution, and stirring to generate sol; and standing and aging the obtained sol to obtain gel. In the sol-gel reaction process, the temperature of the standing and aging is generally 0 to 60 ℃, preferably 10 to 30 ℃, and the time of the standing and aging is 0 to 24 hours, preferably 2 to 12 hours. The hydrolytic agent is generally an acid or an alkali, and the concentration of the hydrolytic agent is 0.5mol/L to 2mol/L, such as 0.5mol/L, 1mol/L, 1.5mol/L, 2mol/L and the like. The acid is selected from one or more of hydrochloric acid, sulfuric acid, nitric acid, formic acid, acetic acid, oxalic acid and citric acid, and the base is selected from one or more of ammonia water, triethylamine, ethylenediamine and tetramethylethylenediamine. Drying and roasting the product after the sol-gel reaction, wherein the drying temperature is 60-120 ℃, preferably 100-120 ℃, the roasting temperature is 300-700 ℃, and the roasting time is 2-6 h. Then, the roasted product is reduced at 400-600 deg.c for 2-6 hr. And reducing to obtain a compound of crystalline nickel and amorphous silicon dioxide, namely the hydrogenation saturation catalyst.

In some embodiments, the nickel source used in the aforementioned precipitation method or sol-gel method is a soluble nickel source, and may be one or more of basic nickel carbonate, nickel nitrate, nickel sulfate, nickel chloride and nickel acetate, and the silicon source is a soluble silicon source, and may be one or more of water glass, silica sol and ethyl orthosilicate; the alkali is one or more selected from sodium hydroxide, potassium hydroxide, ammonia water, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate and ammonium carbonate. The molar ratio of the nickel source to the silicon source is 1 (0.1 to 40), for example, 1. In one embodiment, the molar ratio of the nickel source to the silicon source is 1 (2-15).

The prepared hydrogenation saturation catalyst is used in the hydrogenation saturation reaction, whereinThe hydrogenation saturation reaction temperature is 0 to 200 ℃ such as 0 ℃,12 ℃, 35 ℃, 46 ℃, 58 ℃, 70 ℃, 75 ℃, 80 ℃ and 94 ℃, and is generally lower than the hydrodeoxygenation temperature. The reaction pressure is 0.5MPa to 15MPa, for example, 0.5MPa, 1.6MPa, 3MPa, 4.5MPa, 5MPa, 6.7MPa, 7.2MPa, 10MPa, 13MPa, etc. The mass space velocity is 0.1h ^-1 ～10h ^-1 For example, 0.7h ^-1 、1h ^-1 、3h ^-1 、5.5h ^-1 、7.2h ^-1 、10h ^-1 And the like. The hydrogen-oil volume ratio is 50 to 3000, and may be further 300 to 1000, for example, 500, 600, 800, or the like.

In step S3, the hydrogenation-deoxidation reaction of the hydrogenation-saturated product includes: the hydrogenation saturated product is subjected to hydrogenation deoxidation reaction in a fixed bed reactor containing a hydrogenation deoxidation catalyst, and then the biodiesel component oil (C) is obtained after fractionation ₈ ～C ₁₆ Long chain alkanes). Wherein, the reaction can be carried out under the condition of solvent or no solvent, and the temperature of the hydrodeoxygenation reaction is 100-400 ℃, for example, 110 ℃, 220 ℃, 350 ℃, 380 ℃ and the like. The reaction pressure is 0.5MPa to 15MPa, for example, 0.5MPa, 1.6MPa, 3MPa, 4.5MPa, 5MPa, 6.7MPa, 7.2MPa, 10MPa, 13MPa, etc. The mass space velocity is 0.1h ^-1 ～10h ^-1 For example, 0.7h ^-1 、1h ^-1 、3h ^-1 、5.5h ^-1 、7.2h ^-1 、10h ^-1 And the like. The hydrogen-oil volume ratio is 50 to 3000, and may be further 300 to 1000, for example, 500, 600, 800, or the like.

The hydrodeoxygenation catalyst is a specific supported catalyst and comprises a first carrier and a first active metal loaded on the first carrier, wherein the first active metal is selected from one or more of nickel, molybdenum, tungsten, cobalt, palladium and platinum, and the first carrier is M- (SiO) ₂ ) _X The composite oxide, M is selected from one or more of niobium oxide, cobalt oxide and cerium oxide, x is 1-100, for example, x can be 4.4, 13, 20.6, 27.2, 31.4, 50.8, 56.6, 73.8, 79.4, 94.2, 99.6, etc. The metal-silicon composite oxide prepared by a sol-gel method is used as a carrier, corresponding active metal is loaded on the carrier, and the obtained material has good hydrogenationThe catalyst has high deoxidation catalytic activity, high stability and reusability, and has good effect when being used for catalyzing a condensation product of a sugar platform compound to carry out hydrodeoxygenation reaction to prepare liquid alkane.

In some embodiments, M is Nb in an amorphous structure ₂ O ₅ And x is 1 to 40. Nb of amorphous structure ₂ O ₅ The catalyst has good capability of activating carbon-oxygen bonds in the hydrodeoxygenation process, promotes the disconnection of the carbon-oxygen bonds, and is beneficial to the catalytic deoxygenation reaction. The first active metal is selected from one or more of palladium, nickel and platinum, and the loading amount of the first active metal is 0.05wt% to 30wt%, for example, 0.2wt%,1.5wt%,2wt%,2.6wt%,8wt%,12wt%,15wt%,18wt%,20wt%, etc., preferably 0.1wt% to 25wt%, more preferably 0.2wt% to 20wt%. The load is excessive, and the cost is too high; too small a loading amount means that there are few metal hydrogenation centers, which are not favorable for exerting hydrogenation activity.

Specifically, with Nb ₂ O ₅ -SiO ₂ The composite oxide is taken as an example of a carrier, and the structure of the composite oxide is mainly Nb ₂ O ₅ And SiO ₂ The oxide particle clusters are in a porous structure formed by aggregating the oxide particle clusters, the particle clusters are distributed irregularly, and the cluster size is 200 nm-2000 nm, preferably 300 nm-600 nm. The specific surface area of the carrier was 200m ² /g～700m ² A ratio of 300 to 500 m/g is preferred ² G, e.g. 320m ² /g、360m ² /g、420m ² /g、480m ² And/g, etc. The pore volume is 0.1cc/g to 0.9cc/g, preferably 0.1cc/g to 0.5cc/g, more preferably 0.2cc/g to 0.4cc/g, for example, 0.21cc/g, 0.28cc/g, 0.32cc/g, 0.38cc/g, etc. Further, the foregoing SiO ₂ Is an amorphous structure. The cluster aggregation structure with specific porous holes is beneficial to loading of active metal, promotes diffusion of raw material molecules and improves catalytic activity.

The preparation method of the hydrodeoxygenation catalyst can adopt a coprecipitation method or a sol-gel method and an impregnation method, for example, a hydrolytic agent and water are added into a mixture of an M precursor and a silicon precursor to carry out sol-gel reaction, or alkali is added into the mixture of the M precursor and the silicon precursor to carry outCarrying out coprecipitation reaction; then roasting the obtained product to obtain M- (SiO) ₂ ) _X A composite oxide; with the M- (SiO) ₂ ) _X And (3) taking the composite oxide as a carrier, preparing an active metal salt solution as an impregnation solution, and loading the active metal on the carrier by adopting an impregnation method to obtain the hydrodeoxygenation catalyst. Similar to the aforementioned hydrosaturation catalyst, a shaping treatment may also be performed during the preparation of the hydrodeoxygenation catalyst to further improve its mechanical strength.

In some embodiments, the M precursor is selected from one or more of citrate, tartrate, malate, nitrate, hydrochloride, and sulfate salts of M, with M being niobium pentoxide (Nb) ₂ O ₅ ) For example, the M precursor may be one or more of niobium citrate, niobium tartrate and niobium malate, and the silicon precursor may be one or more selected from water glass, silica sol and tetraethoxysilane. The hydrolytic agent in the sol-gel method is an acid or an alkali, and the concentration of the hydrolytic agent is 0.5mol/L to 2mol/L, for example, 0.5mol/L, 1mol/L, 1.5mol/L, 2mol/L, and the like. The acid is selected from one or more of hydrochloric acid, sulfuric acid, nitric acid, formic acid, acetic acid, oxalic acid and citric acid, and the base is selected from one or more of ammonia water, triethylamine, ethylenediamine and tetramethylethylenediamine. The alkali in the coprecipitation method is one or more selected from sodium hydroxide, potassium hydroxide, ammonia water, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate and ammonium carbonate.

The hydrodeoxygenation catalyst prepared by the method has a relatively larger specific surface area due to the special structure of the carrier, and the porous structure is beneficial to the diffusion of raw material molecules, so that the integral catalytic performance is improved. In addition, the catalyst has the characteristics of easy separation and good reusability, so that the catalyst is suitable for the method of the invention, and can further improve the overall reaction conversion rate and yield and ensure the subsequent reaction.

The biodiesel component oil obtained by the process can fully realize the catalytic conversion based on the biomass-based sugar platform compound, and the yield of the paraffin component oil of the biodiesel is higher than 90 percent, thereby being beneficial to the comprehensive utilization of agricultural and forestry wastes and realizing the green sustainable development.

The invention will now be further illustrated by the following examples, but is not to be construed as being limited thereto.

The invention adopts a Fourier transform infrared spectrometer produced by German Bruker company to carry out infrared analysis (FT-IR), a sample absorbs infrared light with specific frequency, so that a detector detects that the intensity of interference light changes, interference light intensity signals under different moving mirror moving distances are obtained, then Fourier transform is carried out to obtain a curve of the change of the light intensity along with the frequency, and the resolution ratio is 4cm ^-1 Scanning 16 times;

the nuclear magnetic resonance hydrogen spectrum analysis (1H-NMR) of the product is carried out on a nuclear magnetic resonance spectrometer produced by Varian corporation in America, a sample is scanned by changing the magnetic field intensity, a receiver displays a series of absorption signals which are characterized by gyromagnetic ratio, and related analysis is carried out in sequence, and the temperature control range is-150-180 ℃;

the hydrogenation product of the invention is qualitatively and quantitatively analyzed on a mass spectrum detector and a hydrogen flame ion detector of an Agilent 5977A-7890B gas chromatograph-mass spectrometer respectively.

The catalyst strength in the present invention refers to the radial (i.e., the direction passing through the axis line in the radial plane) strength of the strip catalyst; the strength was measured using a mechanical strength meter.

Preparation example 1

This preparation example is intended to illustrate the preparation process of the hydrosaturation catalyst of the present invention.

Weighing 290g Ni (NO) ₃ ) ₂ ·6H ₂ Dissolving O and 1600g of silica sol (solid content is 30%) in deionized water to prepare a solution a of 1.0mol/L calculated by Ni ions; preparing 1.0mol/L sodium hydroxide solution b; keeping the solution a in a stirring state, and slowly adding the solution b into the solution a until the pH value of the system is 10.5. After the dropwise addition, stirring is continued for 1h, then stirring is stopped, and standing and aging are carried out for 8h. Then filtering and washing the precipitate to neutrality, drying the filter cake in a forced air drying oven at 110 ℃ for 12hAnd then calcined in a muffle furnace for 3 hours at 500 ℃.

Uniformly mixing 160.0g of roasted product, 140.0g of silica sol (with the solid content of 30 percent), 1.0g of citric acid, 10.0g of sesbania powder and 40.0g of water, repeatedly kneading, extruding into cylindrical thin strips with the diameter of 1.8mm by using a strip extruding machine, cutting into strips with the length of 3-5 mm, drying at 120 ℃ for 4h, and roasting at 500 ℃ for 4h; finally, hydrogen reduction at 400 ℃ for 3h gave a catalyst in the form of a strip having a mechanical strength of 18.9N/mm.

Fig. 2 shows an XRD spectrum of the hydrogenation saturation catalyst in preparation example 1. As seen from fig. 2: the catalyst has no obvious SiO ₂ Diffraction characteristic peak, indicating SiO ₂ Exist in an amorphous structure. In addition, the catalyst of preparation example 1 has a characteristic peak of Ni diffraction, which indicates that Ni is also present in a crystal structure.

Preparation example 2

This preparation example is intended to illustrate the preparation process of the hydrodeoxygenation catalyst of the invention.

Preparing 0.5mol/L niobium citrate solution a, weighing 14.6g of Tetraethoxysilane (TEOS) and placing the Tetraethoxysilane (TEOS) in 7.9mL of solution a to obtain mixed solution b, then adding citric acid (the weight ratio of the citric acid to the TEOS is 0.2. The gel is dried in a forced air drying oven at 100 ℃ for 12h and then roasted in a muffle furnace at 600 ℃ for 5h to obtain a white solid.

PdCl with Pd content of 5g/L ₂ Transferring 3mL of the solution c to prepare a maceration extract d, putting the solution d into 2g of the white solid by an isometric maceration method, uniformly stirring, standing for 12h, and drying in a forced air drying oven at 100 ℃ for 12h; and roasting the mixture for 4 hours at 500 ℃ in a muffle furnace to obtain yellow solid, and finally reducing the yellow solid for 2 hours at 200 ℃ in a hydrogen reduction furnace to obtain the hydrodeoxygenation catalyst.

FIG. 3 is an XRD pattern of the hydrodeoxygenation catalyst of preparation example 2, and from FIG. 3, it can be seen that SiO in the catalyst prepared by the sol-gel method ₂ Exist in an amorphous structure. Active centers Pd and Nb ₂ O ₅ No obvious diffraction peak is generated, which is because the load of Pd is low and the active center Pd is in a high dispersion state; while the loading capacity is higherNb ₂ O ₅ Is an amorphous structure. In general, the better the active center dispersion, the higher the catalytic activity, which verifies the Pd/Nb ratio ₂ O ₅ -SiO ₂ The catalyst has good catalytic activity.

The following examples 1 to 11 are intended to illustrate the aldol condensation reaction in the process of producing a biodiesel component oil of the present invention.

Example 1

600mL of 0.3mol/L NaOH aqueous solution is prepared, 115.4g of furfural and 34.9g of acetone are added, and then the mixture is stirred and reacted at 20 ℃ for 24 hours. After the reaction is finished, filtering, washing and drying are carried out to obtain yellow granular crystals, 122.9g of crystals C are weighed ₁₃ The quality yield of the oxygen-containing intermediate (difurfurylideneacetone) is 95.9 percent, and the purity is 99.1 percent. FIG. 4 shows the C-NMR spectrum of the condensation product of example 1, FIG. 5 shows the H-NMR spectrum of the condensation product of example 1, FIG. 6 shows the IR spectrum of the condensation product of example 1, and it can be seen that the condensation product difurfurylideneacetone was successfully obtained

The filtered waste lye is recycled for 6 times by repeating the steps, and the yield is as follows 1:

TABLE 1

Example 2

0.3mol/L of Na is prepared ₂ CO ₃ 600mL of the aqueous solution was added 115.4g of furfural and 34.9g of acetone, followed by stirring at 20 ℃ for 6 hours. After the reaction is finished, yellow granular crystals are obtained by filtering, washing and drying, 117.9g of yellow granular crystals are obtained by weighing, the yield of the product is 92.0 percent, and the purity is 97.3 percent.

The filtered waste lye is recycled for 1 time by repeating the steps, and the yield is as follows 2:

TABLE 2

Example 3

600mL of 0.3mol/L ammonia water is prepared, 115.4g of furfural and 34.9g of acetone are added, and then the mixture is stirred and reacted at 10 ℃ for 6 hours. After the reaction is finished, the yellow granular crystal is obtained by filtering, washing and drying, and 120.1g is obtained by weighing, the yield of the product is 93.7 percent, and the purity is 97.9 percent.

The filtered waste lye is recycled for 3 times by repeating the steps, and the yield is as follows 3:

TABLE 3

Example 4

600mL of 0.3mol/L KOH aqueous solution is prepared, 115.4g of furfural and 34.9g of acetone are added, and then the mixture is stirred and reacted at 20 ℃ for 6 hours. After the reaction is finished, yellow granular crystals are obtained by filtering, washing and drying, 119.7g of yellow granular crystals are obtained by weighing, the yield of the product is 93.4 percent, and the purity is 99.2 percent.

The filtered waste lye is recycled for 6 times by repeating the steps, and the yield is as follows 4:

TABLE 4

Example 5:

400mL of 0.3mol/L NaOH aqueous solution is prepared, 115.4g of furfural and 34.9g of acetone are added, and then the mixture is stirred and reacted at 20 ℃ for 12 hours. After the reaction is finished, yellow granular crystals are obtained by filtering, washing and drying, 119.7g of yellow granular crystals are obtained by weighing, the yield of the product is 93.4 percent, and the purity is 99.2 percent.

The filtered waste lye is recycled for 2 times by repeating the steps, and the yield is as follows 5:

TABLE 5

Example 6

800mL of 0.3mol/L KOH aqueous solution was prepared, 115.4g of furfural and 34.9g of acetone were added, and then the reaction was stirred at 20 ℃ for 4 hours. After the reaction is finished, filtering, washing and drying are carried out to obtain yellow granular crystals, and 126.9g of the yellow granular crystals are obtained by weighing, the yield of the product is 99.0 percent, and the purity is 99.2 percent.

The filtered waste lye is recycled for 6 times by repeating the steps, and the yield is as follows 6:

TABLE 6

Example 7

600mL of 0.5mol/L KOH aqueous solution is prepared, 115.4g of furfural and 34.9g of acetone are added, and then the mixture is stirred and reacted at 20 ℃ for 6 hours. After the reaction is finished, yellow granular crystals are obtained by filtering, washing and drying, 126.1g of the yellow granular crystals are obtained by weighing, the yield of the product is 98.2 percent, and the purity is 98.5 percent.

The filtered waste alkali liquor is recycled for 6 times by repeating the steps, and the yield is as shown in the following table 7:

TABLE 7

Example 8

600mL of 0.2mol/L NaOH aqueous solution is prepared, 57.7g of furfural and 34.9g of acetone are added, and then stirring reaction is carried out at 20 ℃ for 6 hours. After the reaction is finished, yellow granular crystals are obtained by filtering, washing and drying, 77.5g of yellow granular crystals are obtained by weighing, and the yield of the oxygen-containing intermediate product is 94.7 percent, wherein the oxygen-containing intermediate comprises C ₈ Oxygen-containing intermediate

And C ₁₃ Oxygen-containing intermediate (difurfurylideneacetone))，C ₈ Oxygen-containing intermediate

Selectivity 58.5%, C ₁₃ The selectivity of the oxygenated intermediate difurfurylideneacetone was 36.7%. Therefore, condensation products with different carbon chain lengths can be obtained in a targeted manner by regulating the proportion of the raw materials.

The filtered waste lye is recycled for 2 times by repeating the steps, and the yield is as follows:

TABLE 8

Example 9

600mL of 0.5mol/L NaOH aqueous solution is prepared, 115.4g of furfural and 17.4g of acetone are added, and then stirring reaction is carried out at 20 ℃ for 6 hours. After the reaction, the reaction mixture was filtered, washed with water and dried to obtain yellow granular crystals, and 10.5g of the yellow granular crystals were weighed. Due to the excess of furfural, most of the product dissolved in the reaction solution, resulting in a severe reduction in product yield. The alkali liquor can not be recycled.

Example 10

600mL of 0.5mol/L NaOH aqueous solution was prepared, 115.4g of furfural and 69.7g of levulinic acid were added, and then the reaction was stirred at 20 ℃ for 6 hours. After the reaction is finished, acid neutralization and separation are carried out to obtain

126.1g is weighed, the product yield is 98.2 percent, and the purity is 98.5 percent. The concentration of the alkali liquor is not enough to be continuously recycled for catalytic reaction due to the neutralization of the acid liquor.

Example 11

600mL of 0.5mol/L NaOH aqueous solution is prepared, 151.3g of 5-hydroxymethylfurfural and 34.9g of acetone are added, and then the mixture is stirred and reacted at 20 ℃ for 6 hours. After the reaction is finished, filtering, washing and drying are carried out to obtain the dimethylol furfurylidene acetone

Weighing 162.1g and obtaining the product yield98.5% and 98.1% purity.

The filtered waste lye is recycled for 6 times by repeating the steps, and the yield is as follows:

TABLE 9

The following examples 12 to 20 are provided to illustrate the hydrogenation saturation reaction in the process of producing a biodiesel component oil according to the present invention, wherein fig. 7 shows a process flow diagram of the hydrogenation saturation reaction according to an embodiment of the present invention.

Examples 12 to 20

As shown in fig. 7, the condensation product obtained after the aldol condensation reaction and the oxygen-containing solvent are placed in a mixer 1, stirred, dissolved, preheated by a heating furnace 2, and then enter a hydrogenation reactor 3 together with hydrogen, and react under the action of the hydrogenation saturation catalyst in preparation example 1, the reacted material is separated into gas-phase and liquid-phase material flows by a first separator 4, wherein the gas-phase material flow hydrogen is recycled after being pressurized. The liquid phase material flow enters a second separator 5, the second separator 5 is a normal pressure separation tower, the material flow at the top of the tower is mixed with a new solvent after being condensed by a condenser 6 and enters a mixer 1, and the tower bottom flows out of the device, wherein the operation conditions and the reaction results of the specific examples 12-20 are respectively shown in a table 10.

Watch 10

The following examples 21 to 28 are provided to illustrate the hydrodeoxygenation reaction in the process of producing a biodiesel component oil according to the present invention, wherein fig. 8 shows a process flow diagram of the hydrodeoxygenation reaction according to an embodiment of the present invention.

Examples 21 to 28

As shown in fig. 8, the hydrogenation saturated product is placed in a mixing tank 21, preheated by a heating furnace 22, and then enters a hydrogenation reactor 23 together with hydrogen, and reacts under the action of the hydrodeoxygenation catalyst of preparation example 2, the reacted material is separated into a gas phase material flow and a liquid phase material flow by a first separator 24, wherein the gas phase material flow is recycled after being pressurized, the liquid phase material flow enters a second separator 25, the second separator 25 is a normal pressure separation tower, and the biodiesel component oil is separated by controlling the distillation range. FIG. 9 is the MS spectrum of tridecane, the hydrodeoxygenation product of example 21, FIG. 10 is the MS spectrum of dodecane, the hydrodeoxygenation product of example 21, and FIG. 11 is the MS spectrum of undecane, the hydrodeoxygenation product of example 21. Specific operating conditions and reaction results are shown in Table 11.

TABLE 11

Comparative example 1

The condensation product obtained in example 1 was directly subjected to hydrodeoxygenation, the test conditions and results are given in table 12 below.

TABLE 12

	Comparative example 1
		Condensation products	Example 1
Mixer atmosphere/pressure, MPa	Nitrogen/0.5
		Preheating temperature of heating furnace,. Degree.C	220
Hydrogen pressure, MPa, of the reactor	3.0
		Reactor temperature, deg.C	240
Mass space velocity, h ^-1	0.80
		Volume ratio of hydrogen to oil, v/v	1500
Condenser temperature,. Degree.C	20
		Conversion rate%	98
Hydrodeoxygenation product (C) ₈ ～C ₁₅ Alkane), yield/%	Yellow liquid, 78%

Comparative example 2

The condensation product of example 1 was subjected to the hydrogenation saturation reaction in accordance with the method of example 12, and the obtained product was subjected to the hydrodeoxygenation reaction in accordance with the method of example 21. Different from the prior art, the adopted catalysts are Raney Ni catalysts in the hydrogenation saturation reaction process, and the adopted catalysts are sulfuration state Ni-W/Al in the hydrogenation deoxidation reaction process ₂ O ₃ A catalyst. After calculation, the obtained hydrogenation saturationThe conversion of the product was 95%, the conversion of the hydrodeoxygenated product 91% and the yield 75%.

Therefore, compared with the traditional hydrogenation catalyst, the hydrogenation saturation catalyst and the hydrogenation deoxidation catalyst have better catalytic activity.

As can be seen from the above examples 1-28 and comparative examples 1-2, the biodiesel component oil prepared by the method of the invention has the characteristics of high conversion rate and high yield, and compared with the method of directly carrying out hydrodeoxygenation reaction on the condensation product, the method of the invention carries out hydrogenation pretreatment, namely hydrogenation saturation treatment on the condensation product, so that the product can obtain higher heat value and chemical stability, side reactions are reduced, and the conversion rate and yield are both improved.

In summary, the preparation method of the biodiesel component oil provided by the invention has the advantages that the synthesis route is redesigned, the hydrogenation saturation treatment is carried out before the hydrodeoxygenation is carried out on the condensation product, and a proper specific catalyst is adopted in each step, so that the side reaction in the whole reaction process is less, the conversion rate and the yield are higher, the production cost is reduced, and the preparation method has a good application prospect. The method can realize catalytic conversion based on the biomass sugar platform compound to prepare the biodiesel component oil, is beneficial to comprehensive utilization of agricultural and forestry wastes, and realizes green sustainable development.

It should be noted by those skilled in the art that the described embodiments of the present invention are merely exemplary and that various other substitutions, alterations, and modifications may be made within the scope of the present invention. Accordingly, the present invention is not limited to the above-described embodiments, but is only limited by the claims.

Claims

1. A preparation method of biodiesel component oil is characterized by comprising the following steps:

performing aldol condensation reaction on lignocellulose-based furfural compound and carbonyl compound to obtain C ₈ ～C ₁₆ A long chain oxygen-containing compound;

for the C ₈ ～C ₁₆ Carrying out hydrogenation saturation on the long-chain oxygen-containing compound; and

hydrodeoxygenation is carried out on the hydrogenation saturated product, and the hydrodeoxygenated product is fractionated to obtain the biodiesel component oil;

the aldol condensation reaction is carried out under the action of a base catalyst;

the hydrogenation saturation is carried out under the action of a hydrogenation saturation catalyst, and the hydrogenation saturation catalyst comprises a compound of nickel and silicon dioxide, wherein the silicon dioxide is in an amorphous structure, and the nickel is in a crystal structure;

the hydrodeoxygenation is carried out under the action of a hydrodeoxygenation catalyst, the hydrodeoxygenation catalyst comprises a first carrier and a first active metal loaded on the first carrier, wherein the first active metal is selected from one or more of nickel, molybdenum, tungsten, cobalt, palladium and platinum, and the first carrier is M- (SiO) ₂ ) _X The composite oxide, M is selected from one or more of niobium oxide, cobalt oxide and cerium oxide, and x is 1-100.

2. The preparation method according to claim 1, wherein the lignocellulose-based furfural compound is selected from one or more of furfural and 5-hydroxymethyl furfural, the carbonyl compound is an α -H carbonyl compound, the α -H carbonyl compound is selected from one or more of acetone and levulinic acid, and the molar ratio of the lignocellulose-based furfural compound to the carbonyl compound is 1.

3. The preparation method of claim 1, wherein the base catalyst is an inorganic base selected from one or more of sodium hydroxide, potassium hydroxide, ammonia water, sodium carbonate and potassium carbonate, and the molar concentration of the inorganic base is 0.05mol/L to 1mol/L.

4. The method according to claim 1, wherein the compound of nickel and silica has a chemical formula of Ni- (SiO) ₂ ) _a And a has a value of 0.1 to 40.

5. The method of claim 1The preparation method is characterized in that the hydrogenation saturation comprises the following steps: subjecting the C to ₈ ～C ₁₆ Dissolving a long-chain oxygen-containing compound in an organic solvent, and carrying out hydrogenation saturation reaction on the obtained solution in a fixed bed reactor containing the hydrogenation saturation catalyst, wherein the organic solvent is an oxygen-containing solvent, the oxygen-containing solvent is selected from one or more of methanol, ethanol and acetone, and C in the solution ₈ ～C ₁₆ The mass percentage of the long-chain oxygen-containing compound is 0.5-50%.

6. The preparation method of claim 1, wherein the hydrogenation saturation reaction temperature is 0-200 ℃, the reaction pressure is 0.5-15 MPa, and the mass space velocity is 0.1h ^-1 ～10h ^-1 The volume ratio of hydrogen to oil is 50-3000.

7. The method according to claim 1, wherein M is Nb having an amorphous structure ₂ O ₅ X is 1 to 40; the first active metal is selected from one or more of palladium, nickel and platinum, and the loading amount of the first active metal is 0.05-30 wt%.

8. The method according to claim 1, wherein the first carrier is composed of M and SiO ₂ Porous structure of oxide particles cluster-aggregated SiO ₂ The carrier is an amorphous structure, the size of the cluster is 200 nm-2000 nm, and the specific surface area of the first carrier is 200m ² /g～700m ² (iii) a pore volume of 0.1cc/g to 0.9cc/g.

9. The method of claim 1, wherein the hydrodeoxygenation comprises: the hydrogenation saturated product is subjected to hydrogenation deoxidation reaction in a fixed bed reactor containing the hydrogenation deoxidation catalyst, wherein the reaction temperature is 100-400 ℃, the reaction pressure is 0.5-15 MPa, and the mass space velocity is 0.1h ^-1 ～10h ^-1 The volume ratio of hydrogen to oil is 50-3000.

10. A biodiesel component oil prepared by the method of any one of claims 1 to 9.