CN114891535A - Method for preparing sustainable aviation fuel oil from agricultural and forestry waste - Google Patents

Method for preparing sustainable aviation fuel oil from agricultural and forestry waste Download PDF

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CN114891535A
CN114891535A CN202210460245.7A CN202210460245A CN114891535A CN 114891535 A CN114891535 A CN 114891535A CN 202210460245 A CN202210460245 A CN 202210460245A CN 114891535 A CN114891535 A CN 114891535A
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kettle
levulinic acid
tower
agricultural
aviation fuel
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CN114891535B (en
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王晨光
马升勇
王海永
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Guangzhou Institute of Energy Conversion of CAS
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Guangzhou Institute of Energy Conversion of CAS
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    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
    • C10G67/00—Treatment of hydrocarbon oils by at least one hydrotreatment process and at least one process for refining in the absence of hydrogen only
    • C10G67/02—Treatment of hydrocarbon oils by at least one hydrotreatment process and at least one process for refining in the absence of hydrogen only plural serial stages only
    • C10G67/14—Treatment of hydrocarbon oils by at least one hydrotreatment process and at least one process for refining in the absence of hydrogen only plural serial stages only including at least two different refining steps in the absence of hydrogen
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
    • C07C51/42—Separation; Purification; Stabilisation; Use of additives
    • C07C51/43—Separation; Purification; Stabilisation; Use of additives by change of the physical state, e.g. crystallisation
    • C07C51/44—Separation; Purification; Stabilisation; Use of additives by change of the physical state, e.g. crystallisation by distillation
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D307/00—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom
    • C07D307/02—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings
    • C07D307/34—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings having two or three double bonds between ring members or between ring members and non-ring members
    • C07D307/38—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings having two or three double bonds between ring members or between ring members and non-ring members with substituted hydrocarbon radicals attached to ring carbon atoms
    • C07D307/40—Radicals substituted by oxygen atoms
    • C07D307/46—Doubly bound oxygen atoms, or two oxygen atoms singly bound to the same carbon atom
    • C07D307/48—Furfural
    • C07D307/50—Preparation from natural products
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P30/00—Technologies relating to oil refining and petrochemical industry
    • Y02P30/20—Technologies relating to oil refining and petrochemical industry using bio-feedstock

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Engineering & Computer Science (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

The invention discloses a method for preparing sustainable aviation fuel oil from agricultural and forestry wastes. The method comprises the following steps: (1) crushing the agricultural and forestry waste, carrying out acid catalytic stripping, and rectifying and concentrating the obtained stripping gas to obtain a furfural aqueous solution; (2) treating the stripped residues with alkali liquor to obtain cellulose with lignin removed, performing acid hydrolysis to obtain hydrolysate containing levulinic acid, and performing extraction-rectification treatment to obtain levulinic acid; (3) carrying out condensation reaction on a furfural aqueous solution and levulinic acid under the catalysis of alkali, and carrying out filter pressing and drying to obtain a condensation solid; (4) uniformly dispersing the condensed solid into aviation fuel oil through emulsification equipment, and carrying out continuous hydrogenation in a series reaction kettle to obtain a primary hydrogenation liquid; (5) and atomizing the primary hydrogenation liquid and hydrogen by an atomizer, and then carrying out hydrodeoxygenation/cracking/isomerization reaction in a fixed bed reactor to obtain a sustainable aviation fuel product.

Description

Method for preparing sustainable aviation fuel oil from agricultural and forestry waste
Technical Field
The invention relates to the technical field of preparation of sustainable biological aviation fuel oil, in particular to a method for preparing sustainable bio-based aviation fuel oil from agricultural and forestry wastes rich in hemicellulose and cellulose, such as bagasse, corn stalks, corncobs, rice stalks, wheat stalks, sorghum stalks, cotton stalks and the like, and specifically relates to a method for preparing sustainable aviation fuel oil from agricultural and forestry wastes.
Background
From the global carbon emission total, the aviation industry is not the main industry of carbon emission, but is absolutely the difficult industry of carbon emission reduction, and the main reason is that long-distance flight still needs a jet/propeller engine consuming fossil fuel (the vast majority of carbon dioxide emission of civil aviation transportation comes from flight over 1500 kilometers), and other new energy sources are difficult to use on civil aviation airliners.
In 2016, the 39 th generation of International Civil Aviation Organization (ICAO) passed historically significant international aviation carbon offset and abatement programs, and major considerations include: 1. and (2) improving the fuel consumption efficiency, and using Sustainable Aviation Fuel (SAF). Sustainable Aviation Fuels (sustamable Aviation Fuels) are an advantageous choice for green flight due to their low carbon emission intensity, and SAF is considered the most potential Aviation fuel because it can reduce carbon emissions by as much as 85% compared to regular jet fuel.
SAF is synthesized from alternative, renewable energy sources in a sustainable way. The raw materials of the SAF include vegetable oils, algae, greases, animal fats, wastewater, alcohols, sugar derivatives and carbon dioxide, but will eventually be converted to hydrocarbon mixtures like petrochemical aviation fuels. The SAF has sustainability, and the processes of raw material generation, production and distribution meet the social, economic and environmental targets, namely, the consumption of natural resources is reduced, and the ecological balance is kept. Compared with commercial jet fuel, the SAF can reduce the carbon footprint of the life cycle and is very important for assisting the global aviation industry to realize the emission reduction target.
The SAF preparation process disclosed in the prior patent mainly includes the following two types:
1. hydrodeoxygenation (or esterification and hydrodeoxygenation are carried out on animal and vegetable oil or waste cooking oil) and hydroisomerization are carried out to prepare aviation fuel oil and byproducts of biological gasoline and biodiesel, such as the following patents: CN104371758B, CN104525247B, CN105921168B, CN106268937B, CN106281401B, CN111909722A, CN112608766A and CN 113652272A. The significant problems in producing SAF fuel from grease-based raw materials include: (1) the grease has the problems of 'competing for grains with people and competing for land with grains', thus threatening the national grain safety; (2) the cost of the grease or the waste cooking oil is high, and the SAF produced by the grease or the waste cooking oil as a raw material is 2-3 times of the price of the petroleum-based aviation kerosene; (3) the oil or the waste cooking oil is little, and the requirement of large-scale use in the aviation industry is difficult to meet.
2. Utilizing sugar platform molecules after hydrolysis of lignocellulose biomass, such as furfural molecules and acetone aldol condensation, aldehyde compounds and furan compounds aldol condensation, furfural compounds and levulinate compounds aldol condensation, so as to obtain a condensation intermediate with a carbon chain length meeting the requirements of aviation fuel oil, then carrying out hydrogenation saturation in an alcohol solvent in an intermittent kettle, and then sending hydrogenation saturated liquid to a fixed bed reactor for reactions such as hydrogenation deoxidation/isomerization and the like, thus finally obtaining the aviation fuel oil. The related patents are as follows: chinese patents CN102850157B, CN107200722B, CN103805224B, CN104119943B, CN 104650947B; foreign patent US7671246B 2. There are several problems with this route at present: (1) the condensation raw materials are obtained through complex chemical reaction and purification processes, particularly ketone and furan chemicals, and a large amount of fossil energy is consumed for preparing the substances from biomass, so that the biological aviation oil product is not carbon neutral, and in addition, the price of various sugar platform condensation raw materials is high, and the produced aviation fuel oil has no economic feasibility; (2) petrochemical alcohol or hydrocarbon solvents are used in the condensation process, condensation intermediate hydrogenation and other processes, and petrochemical alkane is used in hydrodeoxygenation/isomerization, so that a carbon source containing a petrochemical group is contained in the aviation oil product; (3) the disclosed technical route is basically free of patents for preparing the SAF aviation oil from a single lignocellulose raw material, and cannot build an integrated and systematic production device which really adopts the lignocellulose raw material, so that the SAF aviation oil cannot be stably supplied on a large scale.
On the basis of the preparation method of the bio-aviation oil proposed by the issued patents (CN104650947B, CN104650948B, CN105779036B and CN106753549B) of the subject group, the whole technical method is improved and upgraded again, the obtained carbon source of the SAF aviation oil fuel comes from agricultural and forestry waste, and the hydrocracking/isomerization catalyst is improved.
In summary, from the patents published at home and abroad, the existing SAF fuel production technologies for bio-aviation kerosene have different technical bottlenecks, and generally have the problems that carbon sources are not completely derived from biomass, production devices cannot be systematized and integrated, raw materials are high in price, the treatment process is complex, the economy is low, and the like, so that the SAF fuel for aviation industry cannot be produced stably in a large scale and economically.
The invention provides a production method for producing fully renewable carbon-based biological aviation oil by adopting agricultural and forestry wastes, aiming at the problems of raw materials, technical routes, catalysts and the like in the production of biomass-based aviation fuel at present, and solves the problems of petrochemical-based carbon source consumption, high energy consumption, high factory building cost and the like in the current domestic and foreign technical routes.
Disclosure of Invention
The method comprises the steps of taking agricultural and forestry wastes as raw materials, obtaining furfural through acid stripping, removing lignin from stripping residues by using alkali liquor, adding acid liquor for cyclic hydrolysis to obtain an levulinic acid aqueous solution, performing extraction-back extraction impurity removal, performing Aldol condensation reaction on the levulinic acid aqueous solution and the rectified and concentrated furfural aqueous solution in an alkaline catalyst environment, dispersing a generated aviation oil precursor into biological aviation oil through an emulsification process, feeding the biological aviation oil into a continuous kettle type hydrogenation saturation reactor, and feeding a product into a fixed bed reactor for hydrodeoxygenation, hydrocracking/isomerization reaction to obtain the sustainable aviation fuel.
The invention aims to provide a method for preparing sustainable aviation fuel oil from agricultural and forestry waste, which comprises the following steps:
(1) the method comprises the following steps of (1) taking agricultural and forestry waste as a raw material, crushing the agricultural and forestry waste by a crusher, uniformly spraying 4-10 wt% of sulfuric acid on the surfaces of particles of the agricultural and forestry waste, putting the agricultural and forestry waste into a stripping kettle, and introducing 140-185 ℃ saturated steam from the bottom of the stripping kettle for stripping to obtain stripping gas and stripped residues; discharging the stripping gas from the top of the stripping kettle, condensing, and then rectifying and concentrating to obtain a furfural aqueous solution;
(2) adding 1-20 wt% of alkali solution which is 4-10 times of the weight of the residue into the stripped residue, introducing air or oxygen at 30-100 ℃, reacting, filtering to separate out cellulose, mixing the cellulose with 4-10 wt% of acid solution, performing hydrolysis reaction at 140-180 ℃ under the condition of 0.3-1 MPa, filtering the obtained product to obtain an aqueous solution containing levulinic acid, adding sulfuric acid into the aqueous solution containing levulinic acid, and repeatedly performing cellulose hydrolysis to obtain an aqueous solution containing 5-15 wt% of levulinic acid;
(3) extracting the levulinic acid aqueous solution obtained in the step (2) containing impurities by using an organic solvent as an extracting agent, and extracting the levulinic acid and the impurities into the organic solvent; the raffinate phase is an aqueous solution containing inorganic acid to obtain an raffinate phase and an organic extract phase containing levulinic acid; preferably, the extraction process is carried out in a continuous extraction tower, the levulinic acid aqueous solution obtained in the step (2) enters from the top of the extraction tower, and the organic solvent enters from the bottom; the extraction tower is a packed tower and comprises regular packing and random packing, and the material of the extraction tower is common stainless steel; the operating pressure of the extraction tower is 0.1-0.5 MPaG, the operating temperature is less than or equal to 50 ℃, and the flow ratio of the hydrolysate to the extractant is 1: 0.5 to 5;
(4) and (4) adding alkali into the organic extraction phase containing the levulinic acid obtained in the step (3), neutralizing sulfuric acid and formic acid in the extraction phase, and then performing centrifugal separation to obtain a mixed solution containing the levulinic acid and an organic solvent.
(5) Purifying and separating the mixed solution containing the levulinic acid and the organic solvent obtained in the step (4) by a rectifying tower, obtaining the levulinic acid with the purity of more than or equal to 99 wt% on the side line of the tower, and obtaining an organic phase containing water and an extractant component on the top of the tower to be reused as the extractant; the rectifying tower is a regular packing or random packing rectifying tower, and the tower body and the packing are made of stainless steel materials; the number of theoretical plates of the rectifying tower is 30-80; the operating conditions of the rectifying tower are as follows: the operation pressure of the tower top is-0.09 to-0.08 MPaG, the temperature of the tower top is 45 to 58 ℃, the operation temperature of the tower kettle is 186 to 225 ℃, and the reflux ratio is 2 to 5;
(6) reacting the furfural aqueous solution obtained in the step (1) with the levulinic acid obtained in the step (5) at the temperature of 20-100 ℃ and normal pressure under the condition of an alkaline water phase to obtain a condensation product of furfural and levulinic acid, wherein the condensation product is insoluble in water, and is subjected to solid-liquid separation through pressure filtration or centrifugation to obtain a solid product, and the obtained solid product is dried to obtain a precursor of the aviation fuel oil; preferably, the molar ratio of levulinic acid to furfural is 1: 1-2;
(7) dispersing the precursor of the aviation fuel oil obtained in the step (6) into the sustainable aviation fuel oil to form uniform emulsion, wherein the mass ratio of the precursor of the aviation fuel oil to the sustainable aviation fuel oil is 1: 5-20, carrying out continuous primary hydrogenation on the emulsion in a multistage series reaction kettle to obtain hydrogenation saturated liquid of an aviation fuel precursor, wherein the reaction conditions are as follows: the temperature is 100-250 ℃, the pressure is 0.5-5 MPa, the catalyst is Raney nickel, Ru/C or Pb/C, and the residence time of the reaction liquid in the kettle is 2-10 hours;
(8) removing the solid catalyst from the primary hydrogenation liquid obtained in the step (7), mixing the primary hydrogenation liquid with hydrogen through an atomizer, and then feeding the mixture into a fixed bed reactor for secondary hydrogenation to obtain secondary hydrogenation liquid, wherein after the secondary hydrogenation liquid is layered, the supernatant is the aviation fuel oil; preferably, the secondary hydrogenation catalyst is a supported metal catalyst, and the carrier is Al 2 O 3 Or SiO 2 The metal is any two combinations of nickel, platinum, niobium and rhodium; the secondary hydrogenation reaction conditions are as follows: 250-400 ℃, 0.4-2 MPa and liquid space velocity of 0.1-2 h -1 。
Specifically, the method for preparing the sustainable aviation fuel oil by using the agricultural and forestry waste comprises the following steps:
(1) taking naturally air-dried agricultural and forestry wastes (such as bagasse, corn stalks, corn cobs, rice stalks, wheat stalks, sorghum stalks, cotton stalks and the like) as raw materials, crushing the raw materials by a crusher, uniformly spraying 4-10 wt% of dilute sulfuric acid on the surfaces of particles of the agricultural and forestry wastes, then loading the particles into a stripping kettle, introducing 140-185 ℃ saturated steam from the bottom of the stripping kettle, carrying out high-temperature stripping to hydrolyze hemicellulose in the agricultural and forestry wastes into pentose, further dehydrating the pentose to generate furfural, discharging the generated furfural from the top of the stripping kettle along with the steam, condensing, and then rectifying and concentrating to obtain a furfural aqueous solution with the mass fraction of-80%.
(2) Adding 1-20% (mass fraction, mass percentage in the method) of alkali solution 4-12 times the weight of the stripped agricultural and forestry waste, introducing air or oxygen at 30-100 ℃, removing lignin in the stripped agricultural and forestry waste, mainly leaving cellulose components in stripped residues, filtering, leaching, mixing cellulose with 4-10% of acid solution in a hydrolysis kettle, carrying out hydrolysis reaction at 140-180 ℃ under 0.3-1 MPa, filtering the obtained product to obtain the aqueous solution containing levulinic acid, adding concentrated sulfuric acid into the aqueous solution, blending into 4-10% of dilute sulfuric acid solution, repeatedly carrying out cellulose hydrolysis, and repeating the steps for 3-6 times to obtain 5-15% of the aqueous solution of the levulinic acid.
(3) The levulinic acid aqueous solution obtained in the step (2) contains a large amount of soluble humins and other impurities, a ketone/furan organic solvent is adopted for extraction, and the levulinic acid and the impurities are extracted into the organic solvent; the raffinate is an aqueous solution containing inorganic acid, and is used as the acid preparation water for the hydrolysis process. The extraction process is carried out in a continuous extraction tower, hydrolysate enters from the top of the extraction tower, and organic solvent enters from the bottom; the extraction tower is a packed tower and comprises regular packing and random packing, and the material of the extraction tower is common stainless steel; the operating pressure of the extraction tower is 0.1-0.5 MPaG, the operating temperature is less than or equal to 50 ℃, and the flow ratio of the hydrolysate to the ketone/furan extractant is 1: 0.5 to 5.
(4) And (3) adding alkali into the organic extract phase containing levulinic acid, adjusting the pH of the aqueous solution to 3.2-4, and then centrifugally separating the humins and sulfate to obtain a pure mixed solution of the levulinic acid and the organic solvent, wherein the organic extract phase containing the levulinic acid contains suspended humins, a small amount of formic acid and a trace amount of sulfuric acid.
(5) And (4) purifying and separating the organic solvent containing the levulinic acid obtained in the step (4) by a rectifying tower, obtaining the levulinic acid with the purity of more than or equal to 99% at the lateral line of the lower part of the tower, and obtaining an organic phase containing water and an extractant component at the top of the tower to be reused as the extractant. The rectifying tower is a regular packing or random packing rectifying tower, and the tower body and the packing are made of stainless steel (SS304 or SS 316); the number of theoretical plates of the rectifying tower is 30-80; operating conditions of the rectifying tower: 0.09 to 0.08MPaG below zero, 45 to 58 ℃ (tower top), 186 to 225 ℃ (tower bottom), and the reflux ratio is 2 to 5.
(6) Reacting the concentrated furfural water solution with impurity-removed levulinic acid at 20-100 ℃ under an alkaline water phase condition at normal pressure to obtain a condensation product of furfural and levulinic acid, wherein the condensation product is insoluble in water, performing solid-liquid separation through pressure filtration/centrifugation, and drying to obtain a precursor of aviation fuel, wherein the molar ratio of levulinic acid to furfural is 1: 1 to 2.
(7) Dispersing the precursor obtained in the step (6) into an SAF aviation fuel product by adopting an emulsifying machine/emulsifying pump to form uniform emulsion, wherein the mass ratio of the precursor to the SAF aviation fuel is 1: 5-20, carrying out continuous primary hydrogenation on the emulsion in a multistage series reaction kettle, wherein the reaction conditions are as follows: 100-250 ℃, 0.5-5 MPa, Raney nickel, Ru/C or Pb/C as catalyst, and the residence time of the reaction liquid in the kettle is 2-10 hours.
(8) And (4) filtering the primary hydrogenation liquid obtained in the step (7) to remove the solid catalyst, continuously conveying the primary hydrogenation liquid to an atomizer through a pump, mixing the primary hydrogenation liquid with high-pressure hydrogen, and then feeding the mixture into a fixed bed reaction kettle for secondary hydrogenation, wherein after the secondary hydrogenation liquid is layered, the supernatant is the aviation fuel. The secondary hydrogenation catalyst is a supported metal catalyst, and the carrier is Al 2 O 3 Or SiO 2 The metal is any two combinations of nickel, platinum, niobium and rhodium; the secondary hydrogenation reaction conditions are as follows: 250-400 ℃, 0.4-2 MPa and liquid space velocity of 0.1-2 h -1 。
The invention designs an integrated technical route for preparing sustainable aviation fuel by agricultural and forestry wastes, and a technical route provided by the invention is shown as a diagram in figure 1. Compared with the published preparation technology of the SAF aviation oil, the technical route provided by the invention has the following advantages: 1) the carbon source in the SAF aviation oil obtained by the technical method is all from hemicellulose and cellulose components in agricultural and forestry waste; 2) the method does not need ketones, furans and the like which can be obtained from the lignocellulose biomass by complex treatment technology, the raw material of the aviation fuel precursor condensation product is directly from the products of steam stripping and hydrolysis of agricultural and forestry wastes, and complex impurity removal and concentration steps are not needed, so that the energy consumption and the cost of the technical method are greatly reduced; 3) the method has the advantages that the agricultural and forestry wastes are treated by alkali liquor before hydrolysis, so that lignin is removed, the byproduct generation amount in the hydrolysis process is reduced, and the yield of the levulinic acid is improved; 4) the method adopts a continuous condensation body emulsification hydrogenation process for pre-hydrogenation, the product aviation oil is used as a dispersing agent, the condensation body is uniformly dispersed into the aviation oil through emulsification equipment, then multi-kettle series continuous hydrogenation is carried out, an alcohol solvent is not required to be additionally introduced, the continuous hydrogenation operation is stable and safe, and the energy consumption is low; 5) the secondary hydrogenation catalyst adopts non-noble metal Ni-based bimetallic supported catalyst, and can carry out hydrogenation under lower pressure, thereby greatly reducing equipment investment.
Preferably, in the steam stripping process in the step (1), the crushed straws are sprayed with 6-9% of dilute sulfuric acid, and the mass ratio of the dilute sulfuric acid to the straw particles is 0.2-0.6: 1, the stripping temperature is 150-180 ℃, the stripping pressure is 0.38-0.9 MPaG, and the stripping time is 2-3 hours.
Preferably, in the steam stripping process in the step (1), the steam stripping gas is used as a heat source of a reboiler of a subsequent furfural concentration, separation and rectification tower, so that the water vapor consumption can be reduced; rectifying the steam stripping condensate at normal pressure to obtain an azeotrope of furfural and water at the tower top, and directly carrying out subsequent condensation reaction without further concentration;
preferably, in the step (2), in the process of treating the stripped residues with the alkali solution, 5-10 wt% of NaOH or KOH aqueous solution which is 6-10 times of the weight of the stripped residues is introduced into a stirring kettle for alkali treatment by air or oxygen, so that lignin in the stripped residues is removed;
preferably, in the cellulose hydrolysis process in the step (2), the obtained hydrolysate is circularly repeated for 4-6 times, the content of levulinic acid in the obtained hydrolysate is 8-15 wt%, and the hydrolysis kettle equipment is made of carbon steel lining hastelloy, 20# alloy or 904L.
Preferably, in the extraction process of step (3), the ketone/furan organic solvent is cyclohexanone, methyl isobutyl ketone, methyl ethyl ketone, tetrahydrofuran, 2-methyltetrahydrofuran, etc.; more preferably, the extractant is cyclohexanone, methyl isobutyl ketone; the operating pressure of the extraction tower is 0.2-0.3 MPaG, and the operating temperature is 30-50 ℃; the flow ratio of the hydrolysate to the organic extractant is 1: 1 to 2.
Preferably, in the neutralization process in the step (4), a jacket enamel kettle is adopted, quick lime is adopted as an alkaline material, and the quick lime is added into the neutralization kettle, so that the pH value of the material in the kettle is 3.2-4.
Preferably, in the rectification process in the step (5), a regular packed column is adopted as a rectification column, the number of theoretical plates of a light component removal column is 50-60, and the operational reflux ratio of the rectification column is 2-3;
preferably, in the condensation process in the step (6), an azeotrope obtained from the top of the furfural rectifying tower and levulinic acid extracted from the rectifying side line are directly added into 1.1-1.5% alkali liquor for reaction, the alkali used as a catalyst is NaOH or KOH, the condensation temperature is 20-50 ℃, and the condensation reaction time is 2-3 hours.
Preferably, in the emulsification process of step (7), the condensation product precursor is continuously dispersed into the SAF aviation oil product by using an emulsification pump, and the emulsification operating conditions are as follows: 0.2-0.5 MPa, and the mass ratio of the precursor to the SAF aviation oil is 1: 8-12;
preferably, in the primary hydrogenation process in the step (8), 3-stage reactors connected in series are adopted, each reactor is arranged from top to bottom, after one reactor is filled with the reaction solution, the reaction solution enters the next-stage reactor by overflow, and the operation conditions are as follows: the reaction pressure of the first kettle is 100-130 ℃, the reaction pressure of the second kettle is 130-160 ℃, the reaction pressure of the third kettle is 150-180 ℃, and the reaction pressure is 1-3 MPa.
Preferably, in the secondary hydrogenation process in the step (9), a fixed bed reaction kettle is adopted, and the catalyst adopts nickel and niobium bimetal supported on Al 2 O 3 The conditions of the secondary hydrogenation reaction are as follows: 280-320 ℃, 0.5-1 MPa and the liquid airspeed of 0.5-1 h -1 The hydrogen-oil ratio is 100-200: 1.
drawings
FIG. 1 is a process flow diagram of the present invention;
the labels in the figure are:
1. the device comprises a stripping kettle, a furfural rectifying tower system, a base treatment kettle, a base treatment liquid conveying pump, a base treatment hydraulic filter, a lignin treatment system, a hydrolysis kettle, a hydrolysis liquid conveying pump, a hydrolysis liquid filter press, a hydrolysis liquid extracting tower, a neutralization kettle, a neutralization liquid conveying pump, a pipeline type centrifugal machine, a hydrolysis liquid rectifying tower, a condensation kettle, a condensation liquid conveying pump, a condensation filter press, a condensation body dryer, a condensation liquid emulsifying pump, a condensation kettle type hydrogenation system, a secondary hydrogenation reactor.
FIG. 2 is a liquid phase nuclear magnetic characterization spectrum of the condensation product.
Figure 3 is a GC-MS plot of the SAF aviation oil product.
Detailed Description
The following examples are further illustrative of the present invention and are not intended to be limiting thereof. Except for special indication, the equipment and the agricultural and forestry wastes (waste corn stalks) used by the invention are conventional commercial products in the technical field.
The process flow diagram of the present invention is shown in figure 1.
Example 1
(1) 200kg of crushed natural air-dried corn straws (containing 20 wt% of water) are sprayed with 70kg of 8 wt% dilute sulfuric acid, and then added into a stripping kettle 1, saturated steam with the pressure of 0.8MPa is introduced into the bottom of the stripping kettle for 2 hours, and the flow rate of the steam is 400kg/h, so that stripping gas and residues after stripping are obtained. The furfural content in the obtained stripping gas is 2.47 wt%, the stripping gas is condensed, and then is rectified and concentrated by a furfural rectifying tower system 2, and the condensate at the tower top is layered to obtain 23.4kg of furfural aqueous solution with the furfural content of 82.2 wt%, and then the furfural aqueous solution enters a subsequent condensation kettle 15.
(2) The stripped residue enters an alkali treatment kettle 3, 2400kg of 5 wt% NaOH aqueous solution is added, air is introduced, the reaction is carried out for 2 hours at 60 ℃, most of lignin in the stripped residue is dissolved, and then 152kg of cellulose (54 wt% of water) is separated by a filter press. 912kg of cellulose and 5 wt% dilute sulfuric acid are added into a hydrolysis kettle 7, 1.0MPaG steam is introduced into a jacket of the hydrolysis kettle to heat the hydrolysis kettle 7, 210kg of steam is introduced into the hydrolysis kettle 7 at the same time, the operation condition of the hydrolysis kettle reaches 0.4MPaG within 0.5 hour, the temperature is 150 ℃, then the jacket is introduced with steam to preserve heat, and the reaction lasts for 2 hours; then opening a valve at the top of the hydrolysis kettle to carry out flash evaporation steam exhaust, condensing the formic acid-containing water vapor which is flashed out in a condenser (condensing liquid is recycled to prepare dilute sulfuric acid) until the pressure of the hydrolysis kettle is reduced to normal pressure, then the hydrolyzed solid-liquid mixture is sent to a hydrolysate pressure filter 9 by a hydrolysate delivery pump 8 for solid-liquid separation, the pressure filtration operating pressure is 0.7MPaG, the hydrolysate after the first pressure filtration returns to the hydrolysis kettle again, the sulfuric acid content of the first-stage filtrate is 3.5wt percent, the levulinic acid content is 2.41wt percent, at the same time, 6.1kg of 98 wt% concentrated sulfuric acid which is lost is supplemented to the hydrolysis kettle, 152kg of cellulose separated by a batch of previous devices is added to the hydrolysis kettle for second heating hydrolysis (steam heating and first hydrolysis), the hydrolysis is circulated for 5 times (the circulating hydrolysis process is from feeding to the hydrolysis kettle to performing solid-liquid separation by a filter press), and then the solid-liquid mixture in the hydrolysis kettle is subjected to filter pressing. 1274kg of hydrolysate with 10.85 wt% of levulinic acid and 3.6 wt% of sulfuric acid is finally obtained, and the yield of the levulinic acid is 13.8% (the mass ratio of the levulinic acid to the natural air-dried corn straw is the same as below);
(3) the hydrolysate is continuously fed to the top of the extraction tower 10 at a flow rate of 200kg/h, the cyclohexanone is continuously fed to the bottom of the extraction tower 10 at a flow rate of 200kg/h, the extraction tower is made of SS304 stainless steel, and SS304 stainless steel random packing is arranged in the extraction tower. In the extraction tower, the hydrolysate and cyclohexanone are in countercurrent contact, levulinic acid in the hydrolysate is extracted to a cyclohexanone phase (224.5kg/h, the levulinic acid content is 9.66 wt%, the sulfuric acid content is 1.35 wt%, and the formic acid content is 0.18 wt%), the levulinic acid is extracted from the top of the extraction tower, a water phase containing a small amount of cyclohexanone is extracted from the bottom of the extraction tower (175.5kg/h, the cyclohexanone content is 7.1 wt%, the sulfuric acid content is 2.37 wt%, and the formic acid content is 2.06 wt%), and the operating pressure of the extraction tower 10 is 0.2MPaG and 40 ℃.
(4) The organic phase at the top of the extraction tower 10 enters a neutralization kettle 11, the neutralization kettle is operated intermittently, 1430.1kg of organic phase in each batch is added with quicklime 11.1kg to neutralize a small amount of sulfuric acid and formic acid, then neutralization liquid is sent to a pipeline type centrifuge 13 through a neutralization liquid conveying pump 12, calcium sulfate solid and insoluble humin in the neutralization liquid are separated, the separated liquid mainly contains cyclohexanone and levulinic acid, 1393kg of each batch enters a levulinic acid rectifying tower 14.
(5) The operation pressure at the top of the levulinic acid rectifying tower 14 is-0.09 MPaG and 46 ℃; the operation conditions of the tower bottom are as follows: the operation reflux ratio is 2 at the temperature of minus 0.085MPaG and 175 ℃, the theoretical plate number of the rectifying tower is 60, and the material of the tower body and the built-in random packing is SS 316. 1254.9kg of cyclohexanone aqueous solution (the component mass fraction is 94.7 wt% of cyclohexanone and 5.1 wt% of water) is obtained from the top of the levulinic acid rectifying tower and is directly used as an extractant for reuse; column side line product yield 135.2kg (levulinic acid content 99 wt%); 3kg of residual liquid in the tower bottom.
(6) Adding 117kg of furfural aqueous solution produced by steam stripping in the step (1) into a condensation kettle for 5 batches, adding 58.8kg of levulinic acid product on the side line of the tower obtained in the step (5), adding 1.25 wt% of sodium hydroxide aqueous solution 1927kg prepared, reacting at normal pressure and 30 ℃ for 2 hours to obtain a condensation product of furfural and levulinic acid (the liquid-phase nuclear magnetism characterization spectrogram of the condensation product is shown in detail in figure 2), wherein the condensation product is insoluble in water, separating by a condensation filter press 17, returning filtrate to the condensation kettle 15, supplementing sodium hydroxide and water, using the filtrate as a catalyst for the condensation process, drying a filter cake by a condensation body dryer 18 to obtain 126.8kg of condensation solid, and obtaining the yield of the condensation solid of 93% (the mass ratio of the condensation solid to the condensation solid theoretically generated by the added levulinic acid, the same applies below).
(7) With SAF aviation oil (the aviation oil is from hundreds tons of biological aviation oil pilot plant of Guangzhou energy research institute of Chinese academy of sciences, the production process is shown in example 24 of Chinese patent CN104650947B, the aviation oil has a heat value of 43.4MJ/kg and a hydrocarbon content of 99.5 wt%) as a dispersant, 126.8kg of condensed solid is dispersed into 1268kg of SAF aviation oil by an emulsion pump 19 to obtain 1394.8kg of condensed solid emulsion. The emulsion was continuously fed into the kettle hydrogenation system 20 at a flow rate of 100kg/h, while a Ru/C catalyst (5 wt% Ru content, loaded on activated carbon, supplied by Merlin manufacturers) was continuously added at a flow rate of 0.15kg/h, in an amount of 0.15 wt% of the emulsion, maintaining the hydrogen pressure at the top of the kettle hydrogenation system at 1MPa, the first kettle at 120 deg.C, the second kettle at 150 deg.C, and the third kettle at 180 deg.C, to obtain 1399.8kg of the first hydrogenation solution. The kettle type hydrogenation system comprises a first kettle, a second kettle and a third kettle. The first kettle, the second kettle and the third kettle are connected in series, namely, a discharge port at the bottom of the first kettle is connected with an upper feed port of the second kettle, and a discharge port at the bottom of the second kettle is connected with an upper feed port of the third kettle. The condensed solid emulsion discharged from the emulsion pump 19 enters the first kettle through the first feed port at the top of the first kettle, and the catalyst enters the first kettle through the second feed port at the top of the first kettle. The hydrogen is divided into three paths, the first path enters the first kettle from the top air inlet of the first kettle, the second path enters the second kettle from the top air inlet of the second kettle, and the third path enters the third kettle from the top air inlet of the third kettle. Discharging the primary hydrogenation liquid from a discharge port at the bottom of a third kettle, wherein the three kettles are connected in series, and the residence time of the reaction liquid is 8 h.
(8) Pressurizing the hydrogenation saturated liquid of the aviation fuel oil precursor obtained by primary hydrogenation by a pump, conveying the hydrogenation saturated liquid to a tubular centrifuge to remove the waste Ru/C catalyst, mixing the hydrogenation saturated liquid with hydrogen by an atomizer 26, then feeding the mixture into a secondary hydrogenation reactor 21, and filling 1.55kg of self-made Ni-Nb/Al in the secondary hydrogenation reactor 21 2 O 3 The catalyst and the preparation method of the catalyst are detailed in step (9), and the operating conditions of the secondary hydrogenation reactor are as follows: 300 ℃, 1MPa, hydrogen-oil ratio of 150: 1, liquid space velocity of 0.6h -1 The product at the bottom of the reactor is subjected to gas-liquid separation through a gas-liquid separator 22, the gas phase is subjected to a hydrogen regeneration system 23 to obtain high-purity hydrogen, the hydrogen is pressurized and recycled through a hydrogen compressor 24, the liquid phase enters an oil-water separator 25 to separate 1354kg of SAF aviation oil, 1268kg of SAF aviation oil added in the step (7) is subtracted, 86kg of SAF aviation oil can be obtained from every 1000kg of agricultural and forestry waste corn straws, the SAF aviation oil product is analyzed by adopting GC-MS (detailed figure 3, the SAF aviation oil GC-MS spectrogram), the hydrocarbon content of the product is 99.5 wt%, the yield of C8-C15 alkane is 91.6 wt% (the product accounts for the mass ratio of all condensed solid theoretically converted into alkane, the following are the same, and the mass contents of all components in the alkane product are 22.6 wt%, 62.8 wt% of branched alkane and 11.7 wt%, and 76.4kg of levulinic acid with the purity of 99% can be obtained.
(9) Ni-Nb/Al used in step (8) 2 O 3 The catalyst is a self-made catalyst, and the preparation method comprises the following steps:
a. 4.0kg of nickel nitrate hexahydrate (with the purity of 99 wt%), 1kg of deionized water and 0.54kg of ethylene glycol (with the purity of 98 wt%) are stirred and mixed for 3 hours under the conditions of normal temperature and normal pressure to obtain a solution, and then 1.5kg of gamma-Al is added into the solution 2 O 3 Continuously stirring and mixing for 3 hours, finally adding 0.52kg of 98 wt% niobium oxalate and continuously stirring and mixing for 5 hours to obtain a mixed solution 7.56kg。
b. The mixed solution obtained in step a was dried at 100 ℃ and normal pressure for 16 hours in an air atmosphere to obtain 6.52kg of a catalyst precursor.
c. And c, roasting the catalyst precursor obtained in the step b for 16 hours in a muffle furnace under the air atmosphere at normal pressure and 420 ℃ to obtain 2.69kg of the Ni-Nb bimetallic catalyst. The catalyst has Ni content of 30 wt% and Nb content of 10 wt%.
Example 2
(1) 200kg of crushed natural air-dried corn straws (containing 20 wt% of water) are sprayed with 80kg of 8 wt% dilute sulfuric acid, and then added into a stripping kettle 1, saturated steam with the pressure of 0.8MPa is introduced into the bottom of the stripping kettle for 2 hours, and the flow rate of the steam is 400kg/h, so that stripping gas and residues after stripping are obtained. The furfural content in the obtained stripping gas is 2.56 wt%, the stripping gas is condensed, and then is rectified and concentrated by a furfural rectifying tower system 2, and the tower top condensate is layered to obtain 24.3kg of furfural aqueous solution with the furfural content of 82.2 wt%, and the furfural aqueous solution enters a subsequent condensation kettle 15.
(2) The stripped residue is put into an alkali treatment kettle 3, 2800kg of 5 wt% NaOH aqueous solution is added, air is introduced, the reaction is carried out for 2 hours at 60 ℃, most of lignin in the stripped residue is dissolved, and then 152kg of cellulose (54 wt% of water) is separated out by a filter press. Adding 912kg of cellulose and 8 wt% dilute sulfuric acid into a hydrolysis kettle 7, introducing 1.0MPaG steam into a jacket of the hydrolysis kettle to heat the hydrolysis kettle, introducing 210kg of steam into the hydrolysis kettle at the same time, leading the operating conditions of the hydrolysis kettle to reach 0.4MPaG and 150 ℃ within 0.5 hour, then introducing steam into the jacket to preserve heat, and reacting for 2 hours; then opening a valve at the top of the hydrolysis kettle to carry out flash evaporation and steam exhaust, condensing the flash evaporated formic acid-containing water vapor in a condenser (recycling the condensate to prepare dilute sulfuric acid) until the pressure of the hydrolysis kettle is reduced to normal pressure, then the hydrolyzed solid-liquid mixture is sent to a hydrolysate pressure filter 9 by a hydrolysate delivery pump 8 for solid-liquid separation, the pressure filtration operating pressure is 0.7MPaG, the hydrolysate after the first pressure filtration returns to the hydrolysis kettle again, the sulfuric acid content of the first-stage filtrate is 4.6wt percent, the levulinic acid content is 2.67wt percent, meanwhile, 21.3kg of 98 wt% concentrated sulfuric acid which is lost is supplemented to the hydrolysis kettle, 152kg of cellulose separated by a batch of previous devices is added to the hydrolysis kettle for second temperature-rise hydrolysis (steam heating is the same as the first hydrolysis), the hydrolysis is circulated for 5 times in this way (the circulating hydrolysis process is from feeding to the hydrolysis kettle to performing solid-liquid separation by a filter press), and then the solid-liquid mixture in the hydrolysis kettle is subjected to filter pressing. 1274kg of hydrolysate with the levulinic acid content of 12.04 wt% and the sulfuric acid content of 4.5 wt% is finally obtained, and the yield of the levulinic acid is 15.3% (the mass ratio of the levulinic acid to the natural air-dried corn straw serving as the raw material, the same applies below);
(3) the hydrolysate is continuously fed to the top of the extraction tower 10 at a flow rate of 200kg/h, the cyclohexanone is continuously fed to the bottom of the extraction tower 10 at a flow rate of 200kg/h, the extraction tower is made of SS304 stainless steel, and SS304 stainless steel random packing is arranged in the extraction tower. In the extraction tower, the hydrolysate and cyclohexanone are in countercurrent contact, levulinic acid in the hydrolysate is extracted to a cyclohexanone phase (228.4kg/h, 10.54 wt% of levulinic acid, 1.73 wt% of sulfuric acid and 0.18 wt% of formic acid), the levulinic acid is extracted from the top of the extraction tower, a water phase containing a small amount of cyclohexanone is extracted from the bottom of the extraction tower (171.6kg/h, 7.65 wt% of cyclohexanone, 2.95 wt% of sulfuric acid and 2.09 wt% of formic acid), and the operating pressure of the extraction tower 10 is 0.2MPaG and 40 ℃.
(4) The organic phase at the top of the extraction tower enters a neutralization kettle 11, the neutralization kettle is operated intermittently, 1454.9kg of organic phase in each batch is added with quicklime 14.4kg to neutralize a small amount of sulfuric acid and formic acid, then neutralization liquid is sent to a pipeline type centrifuge 13 through a neutralization liquid delivery pump 12, calcium sulfate solid and insoluble humin in the neutralization liquid are separated, the separated liquid mainly contains cyclohexanone and levulinic acid, 1412kg of each batch enters a levulinic acid rectifying tower 14.
(5) The operation pressure at the top of the levulinic acid rectifying tower 14 is-0.09 MPaG and 46 ℃; the operation conditions of the tower bottom are as follows: the operation reflux ratio is 2 at the temperature of minus 0.085MPaG and 175 ℃, the theoretical plate number of the rectifying tower is 60, and the material of the tower body and the built-in random packing is SS 316. 1258.7kg of cyclohexanone aqueous solution (the mass fractions of the components are 94.5 wt% of cyclohexanone and 5.3 wt% of water) is obtained from the top of the levulinic acid rectifying tower and directly used as an extracting agent for reuse; the product flow rate of the side line of the column was 150.3kg (levulinic acid content 99 wt%); 3.2kg of residual liquid in the tower bottom.
(6) Adding 121.5kg of furfural aqueous solution generated by steam stripping in the step (1) into a condensation kettle for 5 batches, adding 61kg of levulinic acid product in the tower kettle obtained in the step, adding 2000kg of prepared 1.25 wt% of sodium hydroxide aqueous solution, reacting at normal pressure and 40 ℃ for 2 hours to obtain a condensation product of furfural and levulinic acid, wherein the condensation product is insoluble in water, separating by using a condensation filter press 17, returning filtrate to the condensation kettle 15, supplementing sodium hydroxide and water, then using the filtrate as a catalyst for the condensation process, drying a filter cake by using a condensation body dryer 18 to obtain 133kg of condensation solid, and obtaining the yield of the condensation solid (the mass ratio of the condensation solid to the condensation solid theoretically generated by the added levulinic acid).
(7) With SAF aviation oil (the aviation oil is from hundreds tons of biological aviation oil pilot plant of Guangzhou energy research institute of Chinese academy of sciences, the production process is shown in example 24 of Chinese patent CN104650947B, the aviation oil has a heat value of 43.4MJ/kg and a hydrocarbon content of 99.5 wt%) as a dispersant, 133kg of condensed solid is dispersed into 1330kg of SAF aviation oil by an emulsion pump 19 to obtain 1463kg of condensed solid emulsion. The emulsion was continuously fed into the kettle hydrogenation system 20 at a flow rate of 100kg/h, while a Ru/C catalyst (5 wt% Ru content, loaded on activated carbon, supplied by Merlin manufacturers) was continuously added at a flow rate of 0.15kg/h, the catalyst addition was 0.15 wt% of the emulsion addition, and the primary hydrogenation solution 1468kg was obtained by maintaining the hydrogen pressure at the top of the kettle hydrogenation system at 1MPa in the first kettle at 120 deg.C, in the second kettle at 150 deg.C, and in the third kettle at 180 deg.C. The kettle type hydrogenation system comprises a first kettle, a second kettle and a third kettle. The first kettle, the second kettle and the third kettle are connected in series, namely, a discharge port at the bottom of the first kettle is connected with an upper feed port of the second kettle, and a discharge port at the bottom of the second kettle is connected with an upper feed port of the third kettle. The condensed solid emulsion discharged from the emulsion pump 19 enters the first kettle through the first feed port at the top of the first kettle, and the catalyst enters the first kettle through the second feed port at the top of the first kettle. The hydrogen is divided into three paths, the first path enters the first kettle from the top air inlet of the first kettle, the second path enters the second kettle from the top air inlet of the second kettle, and the third path enters the third kettle from the top air inlet of the third kettle. Discharging the primary hydrogenation liquid from a discharge port at the bottom of a third kettle, wherein the three kettles are connected in series, and the residence time of the reaction liquid is 8 hours.
(8) At a timePressurizing hydrogenation saturated liquid of aviation fuel oil precursor obtained by hydrogenation by a pump, conveying the hydrogenation saturated liquid to a tubular centrifuge to remove the waste Ru/C catalyst, mixing the hydrogenation saturated liquid with hydrogen by an atomizer 26, then feeding the mixture into a secondary hydrogenation reactor 21, and filling 1.55kg of self-made Ni-Nb/Al into the secondary hydrogenation reactor 2 O 3 Catalyst, catalyst preparation details are given in step (9) of example 1, operating conditions of the secondary hydrogenation reactor: 300 ℃, 1MPa, hydrogen-oil ratio of 150: 1, liquid space velocity of 0.6h -1 And (3) carrying out gas-liquid separation on the product at the bottom of the reactor through a gas-liquid separator 22, obtaining high-purity hydrogen from a gas phase through a hydrogen regeneration system 23, pressurizing and recycling the hydrogen through a hydrogen compressor 24, introducing a liquid phase into an oil-water separator 25, separating out 1422kg of SAF aviation oil, subtracting 1330kg of the SAF aviation oil added in the step (7), obtaining 92kg of SAF aviation oil from 1000kg of agricultural and forestry waste corn straws, and obtaining 89.2kg of levulinic acid with the purity of 99%. The SAF aviation oil product is analyzed quantitatively and qualitatively by GC-MS, the hydrocarbon content of the product is 99.6 wt%, and the yield of C8-C15 alkane is 91.6 wt%. (Primary hydrogenation and secondary hydrogenation conditions of condensed solid were the same as in example 1)
Example 3
(1) 200kg of crushed naturally air-dried corn straws (containing 20 wt% of water), acid stripping treatment conditions are the same as those of example 2, stripping gas is condensed and then rectified and concentrated, and condensate liquid at the tower top is layered to obtain 24.3kg of furfural aqueous solution, wherein the furfural content is 82.2 wt%, and the furfural aqueous solution enters a subsequent condensation reaction kettle.
(2) And (3) putting the stripped residue into an alkali treatment kettle, adding 8 wt% NaOH aqueous solution, introducing air, reacting at 60 ℃ for 2 hours to basically dissolve lignin in the stripped residue, and separating 150kg of cellulose (containing 54 wt% of water) by a filter press. 912kg of cellulose and 8 wt% dilute sulphuric acid are added into a hydrolysis kettle, the temperature-rising hydrolysis process conditions are the same as the example 2, and solid-liquid separation of hydrolysate is carried out after 5 times of circulating hydrolysis. Obtaining 1260kg of hydrolysate with the levulinic acid content of 12.68 percent and the sulfuric acid content of 4.5 percent by weight and the levulinic acid yield of 15.98 percent by weight;
(3) the hydrolysate was continuously fed to the top of the extraction column 10 at a flow rate of 200kg/h, cyclohexanone was continuously fed to the bottom of the extraction column 10 at a flow rate of 200kg/h, the hydrolysate and cyclohexanone were brought into countercurrent contact in the extraction column, levulinic acid in the hydrolysate was extracted into a cyclohexanone phase (230kg/h, levulinic acid content 11.03 wt%, sulfuric acid content 1.74 wt%, formic acid content 0.19 wt%), taken from the top of the extraction column, and an aqueous phase containing a small amount of cyclohexanone was taken from the bottom of the extraction column (170kg/h, cyclohexanone content 7.66 wt%, sulfuric acid content 2.94 wt%, formic acid content 2.1 wt%), extraction column 10 operating pressure 0.2MPaG, 40 ℃.
(4) The organic phase at the top of the extraction tower enters a neutralization kettle 11, the neutralization kettle is operated intermittently, 1449kg of organic phase in each batch is added with 14.5kg of quicklime to neutralize a small amount of sulfuric acid and formic acid, then a neutralized liquid is sent to a pipeline type centrifuge 13 through a pump 12, calcium sulfate solid and insoluble humin in the neutralized liquid are separated, the separated liquid mainly contains cyclohexanone and levulinic acid, 1406kg of the liquid in each batch enters an levulinic acid rectifying tower 14.
(5) The operation pressure at the top of the levulinic acid rectifying tower 14 is-0.09 MPaG and 46 ℃; the operation conditions of the tower bottom are as follows: the operation reflux ratio is 2 at the temperature of minus 0.085MPaG and 175 ℃, the theoretical plate number of the rectifying tower is 60, and the material of the tower body and the built-in random packing is SS 316. 1244.88kg of cyclohexanone aqueous solution (the mass fractions of the components are 94.5 wt% of cyclohexanone and 5.3 wt% of water) is obtained from the top of the levulinic acid rectifying tower and is directly used as an extracting agent for reuse; column side line product flow rate 158.2kg (levulinic acid content 99 wt%); 3.3kg of residual liquid in the tower bottom.
(6) Adding 121.5kg of furfural aqueous solution generated by steam stripping in the step (1) into a condensation kettle for 5 batches, adding 61kg of levulinic acid product on the side line of the tower obtained in the step (5), adding 2000kg of prepared 1.25 wt% sodium hydroxide aqueous solution, reacting at normal pressure and 40 ℃ for 2 hours to obtain a condensation product of furfural and levulinic acid, wherein the condensation product is insoluble in water, separating through a condensation filter press 17, returning filtrate to the condensation kettle 15, supplementing sodium hydroxide and water, using the filtrate as a catalyst for the condensation process again, drying a filter cake through a dryer 18 to obtain 133kg of condensation solid, and the yield of the condensation solid is 93 wt%.
(7) With SAF aviation oil (the aviation oil is from hundreds tons of biological aviation oil pilot plant of Guangzhou energy research institute of Chinese academy of sciences, the production process is shown in example 24 of Chinese patent CN104650947B, the aviation oil has a heat value of 43.4MJ/kg and a hydrocarbon content of 99.5 wt%) as a dispersant, 133kg of condensed solid is dispersed into 1330kg of SAF aviation oil by an emulsion pump 19 to obtain 1463kg of condensed solid emulsion. The emulsion was continuously fed into the kettle hydrogenation system 20 at a flow rate of 100kg/h, while a Ru/C catalyst (5 wt% Ru content, loaded on activated carbon, supplied by Merlin manufacturers) was continuously added at a flow rate of 0.15kg/h, the catalyst addition was 0.15 wt% of the emulsion addition, and the primary hydrogenation solution 1468kg was obtained by maintaining the hydrogen pressure at the top of the kettle hydrogenation system at 1MPa in the first kettle at 120 deg.C, in the second kettle at 150 deg.C, and in the third kettle at 180 deg.C. The kettle type hydrogenation system comprises a first kettle, a second kettle and a third kettle. The first kettle, the second kettle and the third kettle are connected in series, namely, a discharge port at the bottom of the first kettle is connected with an upper feed port of the second kettle, and a discharge port at the bottom of the second kettle is connected with an upper feed port of the third kettle. The condensed solid emulsion discharged from the emulsion pump 19 enters the first kettle through the first feed port at the top of the first kettle, and the catalyst enters the first kettle through the second feed port at the top of the first kettle. The hydrogen is divided into three paths, the first path enters the first kettle from a top air inlet of the first kettle, the second path enters the second kettle from a top air inlet of the second kettle, and the third path enters the third kettle from a top air inlet of the third kettle. Discharging the primary hydrogenation liquid from a discharge port at the bottom of a third kettle, wherein the three kettles are connected in series, and the residence time of the reaction liquid is 8 h.
(8) The primary hydrogenation liquid is pressurized by a pump, sent to a tubular centrifuge to remove the waste Ru/C catalyst, mixed with hydrogen by an atomizer, and then enters a secondary hydrogenation reactor 21, and 1.55kg of self-made Ni-Nb/Al is filled in the secondary hydrogenation reactor 2 O 3 Catalyst, catalyst preparation details are given in step (9) of example 1, operating conditions of the secondary hydrogenation reactor: 300 ℃, 1MPa, hydrogen-oil ratio of 150: 1, liquid space velocity of 0.6h -1 The product at the bottom of the reactor is subjected to gas-liquid separation through a gas-liquid separator 22, the gas phase is subjected to high-purity hydrogen through a hydrogen regeneration system 23, the hydrogen is pressurized and recycled through a hydrogen compressor 24, the liquid phase enters an oil-water separator 25, 1422kg of SAF aviation oil is separated, 1330kg of the SAF aviation oil added in the step (7) is subtracted, 92kg of SAF aviation oil can be obtained from every 1000kg of agricultural and forestry waste corn straws, and 99% pure SAF aviation oil can be obtainedDegree of levulinic acid 97.2 kg. The SAF aviation oil product is analyzed quantitatively and qualitatively by GC-MS, the hydrocarbon content of the product is 99.5 wt%, and the yield of C8-C15 alkane is 91.6 wt%.
The invention has not been described in detail and is part of the common general knowledge of a person skilled in the art. The above-described embodiments are merely illustrative of the preferred embodiments of the present invention, and the preferred embodiments are not exhaustive and do not limit the invention to the precise embodiments described. Various modifications and improvements of the technical solution of the present invention may be made by those skilled in the art without departing from the spirit of the present invention, and the technical solution of the present invention is to be covered by the protection scope defined by the claims.

Claims (9)

1. A method for preparing sustainable aviation fuel oil from agricultural and forestry wastes is characterized by comprising the following steps:
(1) the method comprises the following steps of (1) taking agricultural and forestry waste as a raw material, crushing the agricultural and forestry waste by a crusher, uniformly spraying 4-10 wt% of sulfuric acid on the surfaces of particles of the agricultural and forestry waste, putting the agricultural and forestry waste into a stripping kettle, and introducing 140-185 ℃ saturated steam from the bottom of the stripping kettle for stripping to obtain stripping gas and stripped residues; discharging the stripping gas from the top of the stripping kettle, condensing, and then rectifying and concentrating to obtain a furfural aqueous solution;
(2) adding 1-20 wt% of alkali solution which is 4-10 times of the weight of the residue into the stripped residue, introducing air or oxygen at 30-100 ℃, reacting, filtering to separate out cellulose, mixing the cellulose with 4-10 wt% of acid solution, performing hydrolysis reaction at 140-180 ℃ under the condition of 0.3-1 MPa, filtering the obtained product to obtain an aqueous solution containing levulinic acid, adding sulfuric acid into the aqueous solution containing levulinic acid, and repeatedly performing cellulose hydrolysis to obtain an aqueous solution containing 5-15 wt% of levulinic acid;
(3) extracting the levulinic acid aqueous solution obtained in the step (2) containing impurities by using an organic solvent as an extracting agent, and extracting the levulinic acid and the impurities into the organic solvent; the raffinate phase is an aqueous solution containing inorganic acid to obtain an raffinate phase and an organic extract phase containing levulinic acid; preferably, the extraction process is carried out in a continuous extraction tower, the levulinic acid aqueous solution obtained in the step (2) enters from the top of the extraction tower, and the organic solvent enters from the bottom; the extraction tower is a packed tower and comprises regular packing and random packing, and the material of the extraction tower is common stainless steel; the operating pressure of the extraction tower is 0.1-0.5 MPaG, the operating temperature is less than or equal to 50 ℃, and the flow ratio of the hydrolysate to the extractant is 1: 0.5 to 5;
(4) neutralizing sulfuric acid and formic acid in the extraction phase by adding alkali into the organic extraction phase containing the levulinic acid obtained in the step (3), and then performing centrifugal separation to obtain a mixed solution containing the levulinic acid and an organic solvent;
(5) purifying and separating the mixed solution containing the levulinic acid and the organic solvent obtained in the step (4) by a rectifying tower, obtaining the levulinic acid with the purity of more than or equal to 99 wt% on the side line of the tower, and obtaining an organic phase containing water and an extractant component on the top of the tower to be reused as the extractant; the rectifying tower is a regular packing or random packing rectifying tower, and the tower body and the packing are made of stainless steel materials; the number of theoretical plates of the rectifying tower is 30-80; the operating conditions of the rectifying tower are as follows: the operation pressure of the tower top is-0.09 to-0.08 MPaG, the temperature of the tower top is 45 to 58 ℃, the operation temperature of the tower kettle is 186 to 225 ℃, and the reflux ratio is 2 to 5;
(6) reacting the furfural aqueous solution obtained in the step (1) with the levulinic acid obtained in the step (5) at 20-100 ℃ and normal pressure under the condition of an alkaline water phase to obtain a condensation product of furfural and levulinic acid, wherein the condensation product is insoluble in water, and is subjected to solid-liquid separation by pressure filtration or centrifugation to obtain a solid product, and the obtained solid product is dried to obtain a precursor of the aviation fuel oil; preferably, the molar ratio of levulinic acid to furfural is 1: 1-2;
(7) dispersing the precursor of the aviation fuel oil obtained in the step (6) into the sustainable aviation fuel oil to form uniform emulsion, wherein the mass ratio of the precursor of the aviation fuel oil to the sustainable aviation fuel oil is 1: 5-20, carrying out continuous primary hydrogenation on the emulsion in a multistage series reaction kettle to obtain hydrogenation saturated liquid of an aviation fuel precursor, wherein the reaction conditions are as follows: the temperature is 100-250 ℃, the pressure is 0.5-5 MPa, the catalyst is Raney nickel, Ru/C or Pb/C, and the residence time of the reaction liquid in the kettle is 2-10 hours;
(8) removing the solid catalyst from the primary hydrogenation liquid obtained in the step (7), and then passing the primary hydrogenation liquid through an atomizer and hydrogenAfter mixing, feeding the gas into a fixed bed reactor for secondary hydrogenation to obtain secondary hydrogenation liquid, and layering the secondary hydrogenation liquid to obtain supernatant, namely the aviation fuel oil; preferably, the secondary hydrogenation catalyst is a supported metal catalyst, and the carrier is Al 2 O 3 Or SiO 2 The metal is any two combinations of nickel, platinum, niobium and rhodium; the secondary hydrogenation reaction conditions are as follows: at 250-400 ℃, 0.4-2 MPa and liquid airspeed of 0.1-2 h -1 。
2. The method for preparing sustainable aviation fuel oil from agricultural and forestry waste according to claim 1, wherein in the step (2), cellulose hydrolysis is repeated for 3-6 times; preferably, when the hydrolysis of cellulose is repeated, cellulose is also added to the levulinic acid-containing aqueous solution.
3. The method for preparing sustainable aviation fuel oil from agricultural and forestry waste according to claim 1, wherein in the step (2), the stripped residue is subjected to alkali treatment to remove lignin in the raw material, the alkali is NaOH or KOH, and the obtained cellulose is subjected to acid hydrolysis.
4. The method for preparing sustainable aviation fuel oil from agricultural and forestry waste according to claim 1, wherein the extraction process in the step (3) is multi-stage continuous extraction, and the selected extractant is ketone or furan; extracting more than 95 wt% of levulinic acid in the levulinic acid aqueous solution obtained in the step (2) into an extraction phase, simultaneously extracting more than 90 wt% of suspended substances into the extraction phase, and then separating by centrifugation; the raffinate phase is directly used as complex acid water for the hydrolysis procedure.
5. The method for preparing sustainable aviation fuel from agricultural and forestry waste according to claim 1, wherein the alkali in the step (4) is quicklime, calcium hydroxide, barium oxide or barium hydroxide.
6. The method for preparing sustainable aviation fuel from agricultural and forestry waste according to claim 1, wherein the rectification separation process in the step (5) is a side-line production of levulinic acid; removing light components of cyclohexanone, water and formic acid from the top of the tower, and recycling the light components to the extraction tower; the tower bottom is a heavy component substance.
7. The method for preparing sustainable aviation fuel oil from agricultural and forestry waste according to claim 1, wherein in the step (6), Aldol condensation reaction is performed on furfural and levulinic acid in an aqueous phase in the presence of alkaline oxide or hydroxide by using Aldol condensation principle to generate C10-C17 oxygen-containing condensation solid.
8. The method for preparing sustainable aviation fuel oil from agricultural and forestry waste according to claim 1, wherein the primary hydrogenation in the step (7) is performed continuously by adopting a multi-kettle series connection mode.
9. The method for preparing sustainable aviation fuel oil from agricultural and forestry waste according to claim 1, wherein the step (8) is a fixed bed continuous hydrogenation step for removing oxygen element in the precursor to generate C8-C15 n-isoparaffin and cycloparaffin.
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CN104650947A (en) * 2015-02-06 2015-05-27 中国科学院广州能源研究所 Method of preparing long chain alkane for jet fuel by virtue of sugar platform compound
CN104711007A (en) * 2013-12-11 2015-06-17 中国科学院大连化学物理研究所 Preparation method of aviation kerosene or diesel oil scope liquid alkane
CN105779036A (en) * 2016-05-10 2016-07-20 中国科学院广州能源研究所 Method for producing oil for traffic fuel by using straws

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130237728A1 (en) * 2012-03-09 2013-09-12 Conocophillips Company Transportation fuels from biomass oxygenates
CN104711007A (en) * 2013-12-11 2015-06-17 中国科学院大连化学物理研究所 Preparation method of aviation kerosene or diesel oil scope liquid alkane
CN104650947A (en) * 2015-02-06 2015-05-27 中国科学院广州能源研究所 Method of preparing long chain alkane for jet fuel by virtue of sugar platform compound
CN105779036A (en) * 2016-05-10 2016-07-20 中国科学院广州能源研究所 Method for producing oil for traffic fuel by using straws

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