Method for modifying thickened oil by utilizing biomass hydrothermal liquefaction water-phase by-product

Abstract

The invention provides a method for modifying thickened oil by utilizing a biomass hydrothermal liquefaction water-phase byproduct, and relates to the technical field of petroleum processing. The method provided by the invention comprises the following steps: mixing the biomass hydrothermal liquefaction water-phase byproduct and the thickened oil to form a reaction system, and carrying out hydrothermal cracking reaction to obtain the modified oil, the mass ratio of the biomass hydrothermal liquefaction water-phase byproduct to the thickened oil is (3-8): 10, the hydrothermal cracking reaction temperature is 200-320 DEG C, and the hydrothermal cracking reaction time is 6-30 hours. The hydrothermal liquefaction water-phase byproduct is used as a conversion water source for the hydrothermal cracking reaction of the thickened oil, active hydrogen upgrading is provided for the modification of the thickened oil, the viscosity reduction and modification of the thickened oil are realized, meanwhile, the treatment cost of wastewater generated when the target product bio-oil is prepared through the hydrothermal liquefaction reaction of the biomass is reduced, and the economic benefit is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of petroleum processing, and particularly relates to a method for modifying heavy oil by using water phase by-products of biomass hydrothermal liquefaction. BACKGROUND

[0002] With the deepening of exploration and development, conventional oil resources have been difficult to meet the growing demand for energy, and the exploitation and application of heavy and poor heavy oil have gradually attracted people's attention and attention. Compared with light crude oil, heavy oil has the characteristics of high density, high viscosity, high content of sulfur, nitrogen, oxygen and metal impurities, which brings many difficulties to its exploitation, transportation and processing. As a new heavy oil modification method, the water thermal cracking technology can effectively promote the cracking of macromolecular hydrocarbons in heavy oil through the interaction of water and oil under high temperature and high pressure, so as to effectively reduce the viscosity of heavy oil and improve the quality of heavy oil. The current public thermal cracking heavy oil modification scheme needs a higher reaction temperature (380~460℃) to obtain a better viscosity reduction and modification effect. However, when the reaction temperature is too high, the amount of coke will increase significantly, which will affect the modification effect. In addition, the traditional hydrogen donor such as tetrahydro naphthalene, dihydro anthracene and decalin is used in the modification process, which has a high price. After the reaction is completed, it needs to be recovered and utilized by hydrogenation treatment, which increases the recovery device and hydrogenation treatment device and increases the cost. Therefore, it is urgent to provide a heavy oil modification scheme which can have a good modification effect and low cost.

[0003] The prior art CN107142096A discloses a method for modifying and reducing the viscosity of heavy oil by using biomass: the method comprises the following steps: first, biomass such as trees, bamboos, flowers, vines and crops, which are composed of cellulose, hemicellulose or lignin, is dried at a temperature of 100~120℃ for 12~24h and crushed into a powder with a particle size of 80~120 mesh; then, heavy oil and the dried and crushed biomass powder are added into a reaction kettle, the amount of the biomass powder is 2.00~7.00wt% of the mass of the heavy oil, and the reaction is carried out at a temperature of 330~360℃ for 20~40min under the catalysis of metal elements contained in the biomass; finally, the reaction product is cooled to room temperature. Although the method can achieve a good viscosity reduction effect, the reaction temperature is still too high, which affects the energy consumption and increases the probability of biomass coking (biochar formation). SUMMARY

[0004] The present application provides a method for modifying heavy oil by using water phase by-products of biomass hydrothermal liquefaction, which can improve the modification effect of heavy oil, realize waste recycling and reduce production cost.

[0005] The application provides a method for modifying heavy oil by using biomass hydrothermal liquefaction aqueous phase by-product, comprising the following steps: mixing the biomass hydrothermal liquefaction aqueous phase by-product and heavy oil to form a reaction system, and carrying out hydrothermal cracking reaction to obtain modified oil, wherein the mass ratio of the biomass hydrothermal liquefaction aqueous phase by-product to the heavy oil is 3-8:10, the hydrothermal cracking reaction temperature is 200-320 DEG C, and the reaction time is 6-30 h.

[0006] According to the method for modifying heavy oil by using biomass hydrothermal liquefaction aqueous phase by-product, preferably, the method further comprises the step of adding a catalyst into the reaction system, wherein the catalyst comprises one or more of NiO, MoO3, NiO-MoO3 / Al2O3, MoO3 / HZSM-5, Fe3O4, ZrO2, NiO-ZrO2 / HZMS-5, ZrO2 / HZSM-5, NiO-ZrO2 / Al2O3 and ZrO2-MoO3 / HZSM-5.

[0007] According to the method for modifying heavy oil by using biomass hydrothermal liquefaction aqueous phase by-product, preferably, the catalyst is used in an amount of 2.00-10.00 wt% of the mass of the heavy oil, for example, 2 wt%, 4 wt%, 6 wt%, 8 wt%, 10 wt% or any range value formed by the point values.

[0008] According to the method for modifying heavy oil by using biomass hydrothermal liquefaction aqueous phase by-product, preferably, the catalyst is NiO-MoO3 / Al2O3, and the catalyst is used in an amount of 4 wt% of the mass of the heavy oil.

[0009] According to the method for modifying heavy oil by using biomass hydrothermal liquefaction aqueous phase by-product, preferably, the dynamic viscosity of the heavy oil is 800-13500 mPa·s at 60 DEG C, preferably 11000-13500 mPa·s at 60 DEG C. For example, the heavy oil can have a viscosity of 800-850 mPa·s at 60 DEG C or 11000-13500 mPa·s at 60 DEG C.

[0010] According to the method for modifying heavy oil by using biomass hydrothermal liquefaction aqueous phase by-product, preferably, the concentration of phenolic compounds in the biomass hydrothermal liquefaction aqueous phase by-product is 300 mg / L-4000 mg / L. For example, the concentration can be 300 mg / L, 500 mg / L, 800 mg / L, 1000 mg / L, 1500 mg / L, 2000 mg / L, 2500 mg / L, 3000 mg / L, 3500 mg / L, 4000 mg / L or any range value formed by the point values.

[0011] The method for modifying thick oil by using biomass hydrothermal liquefaction water phase by-product according to the present application, preferably, the biomass hydrothermal liquefaction water phase by-product is the water phase by-product of the production of bio-oil by the hydrothermal liquefaction reaction of lignocellulosic biomass and water.

[0012] The method for modifying thick oil by using biomass hydrothermal liquefaction water phase by-product according to the present application, preferably, the biomass hydrothermal liquefaction water phase by-product is extracted from the liquid phase product obtained by the hydrothermal liquefaction reaction of lignocellulosic biomass and water, and the extractant used in the extraction is dichloromethane.

[0013] The method for modifying thick oil by using biomass hydrothermal liquefaction water phase by-product according to the present application, preferably, the temperature of the hydrothermal liquefaction reaction is 200-320℃, the reaction time is 1-6h, and the mass ratio of lignocellulosic biomass to water is 1:5-10. For example, the temperature of the hydrothermal liquefaction reaction can be 200℃, 220℃, 240℃, 260℃, 280℃, 300℃, 320℃, etc. or any range value composed of the point values; the reaction time can be 1h, 2h, 3h, 4h, 5h, 6h, etc. or any range value composed of the point values; and the mass ratio of lignocellulosic biomass to water can be 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, etc. or any range value composed of the point values.

[0014] The method for modifying thick oil by using biomass hydrothermal liquefaction water phase by-product according to the present application, preferably, the lignocellulosic biomass includes one or more of sawdust, sugarcane residue, melon seed shell, rape flower, corn straw, barley straw, cotton straw, straw, pine, poplar and walnut shell.

[0015] Beneficial effects: The method for modifying thick oil by using biomass hydrothermal liquefaction water phase by-product according to the present application uses the hydrothermal liquefaction water phase by-product as the conversion water source of the hydrothermal cracking reaction of thick oil, provides active hydrogen upgrading for the modification of thick oil, realizes the viscosity reduction and modification of thick oil, reduces the treatment cost of waste water generated in the production of target product bio-oil by biomass hydrothermal liquefaction reaction, and improves the economic benefits. DETAILED DESCRIPTION

[0016] The following examples are used to illustrate the present application, but not to limit the scope of the present application. If the specific technology or condition is not specified in the examples, the technology or condition described in the literature in the art or according to the product manual is used. If the reagent or instrument is not specified by the manufacturer, it is a conventional product that can be purchased through a regular channel.

[0017] In order to illustrate that the method for modifying heavy oil by using biomass hydrothermal liquefaction aqueous phase by-product provided by the application is suitable for modification of various heavy oils with wide range of dynamic viscosity, the application provides two heavy oil raw materials with different dynamic viscosity ranges.

[0018] The basic properties of the raw materials Karamay heavy oil (11000-13500 mPa·s, 60℃) and Karamay No. 9 heavy oil (800-850 mPa·s, 60℃) are as follows: The Karamay No. 9 heavy oil is a low-asphaltene heavy oil with asphaltene content less than 1%, and the basic properties are as shown in Table 1. Table 1. Basic properties of low-asphaltene heavy oil

[0019] The polar component includes resin and asphaltene.

[0020] The basic properties of the Karamay heavy oil are as shown in Table 2.

[0021] Table 2. Basic properties of Karamay heavy oil

[0022] The viscosity reduction rate mentioned in the application is equal to (viscosity of heavy oil before modification-viscosity of heavy oil after modification) / viscosity of heavy oil before modification*100%.

[0023] The determination method of the viscosity of heavy oil is as follows: an appropriate amount of oil sample is injected into a sample cup, a suitable rotor is selected according to the approximate viscosity range of the oil sample, and the rotor is slowly immersed into the sample cup; after the oil sample immerses the rotor, a small amount of oil sample is continuously poured to ensure that the oil sample completely immerses the rotor. Then, a heat preservation cover is added on top of the sample tank, and a temperature conduction device is connected to the bottom of the sample tank for convenient temperature measurement. The constant temperature circulating water bath device (model: Brookfield TC-550MX) is opened to heat the oil sample, and after the sample is heated to the target temperature, the rotor speed is set so that the torque is within 40%-60%; after the viscosity is stable, the data is read.

[0024] In the specific embodiment, the application provides a method for modifying heavy oil by using biomass hydrothermal liquefaction aqueous phase by-product, which comprises the following steps: mixing biomass hydrothermal liquefaction aqueous phase by-product and heavy oil to form a reaction system, and carrying out hydrothermal cracking reaction to obtain modified oil; the mass ratio of the biomass hydrothermal liquefaction aqueous phase by-product to the heavy oil is 3-8:10, the hydrothermal cracking reaction temperature is 200-320℃, and the time is 6-30h.

[0025] It should be noted that: Hydrothermal liquefaction technology uses water as the reaction medium. Under high temperature (180~360℃) and high pressure (3~26MPa), macromolecules in biomass undergo a series of reactions, including hydrolysis, decarboxylation, deamination, and repolymerization, ultimately producing bio-oil, aqueous byproducts, gas, and solid residue. Bio-oil is the target product of hydrothermal liquefaction and can be used as fuel or to produce high-value-added products. Aqueous and solid residues are the main byproducts of biomass hydrothermal liquefaction. The aqueous byproducts of lignocellulosic biomass hydrothermal liquefaction mainly include carboxylic acids, ketones, esters, and high concentrations of phenolic compounds. Wastewater containing high concentrations of phenolic compounds has a significant impact on the ecological environment and is difficult to treat.

[0026] In specific embodiments, the heavy oil of the present invention includes inferior and heavy heavy oil. The upgrading method provided by the present invention is a hydrothermal pyrolysis reaction. The reaction temperature is mild, and it does not require the high-temperature environment of over 400°C required by conventional thermal cracking reactions. Furthermore, it does not require delayed coking and upgrading reactions under supercritical hydrothermal conditions (374~450°C). Therefore, the reaction temperature of the present invention only needs to be controlled at 200~320°C. At this temperature, the heavy oil undergoes hydrothermal pyrolysis, i.e., the breaking of CX chemical bonds and the conversion of -H / -OH, which can achieve an irreversible reduction in viscosity, fundamentally improving the quality and fluidity of the heavy oil. The mechanism of heavy oil upgrading through hydrothermal pyrolysis is completely different from that of existing thermal pyrolysis reactions. It does not require a high-temperature environment, therefore the reaction temperature is low and does not reach the coking temperature (350~800°C), thus no coke is generated, significantly improving the upgrading effect of heavy oil.

[0027] In some specific embodiments, for example, the mass ratio of aqueous by-products from biomass hydrothermal liquefaction to heavy oil can be a point value such as 3:10, 4:10, 5:10, 6:10, 7:10, 8:10, or any other range thereof. The reaction temperature of the hydrothermal pyrolysis reaction can be a point value such as 200℃, 220℃, 240℃, 260℃, 280℃, 300℃, 320℃, or any other range thereof, and the reaction time can be a point value such as 6h, 12h, 18h, 24h, 30h, or any other range thereof.

[0028] The aqueous phase byproducts of biomass hydrothermal liquefaction mentioned in this invention are also different from those of general biomass high-temperature steam liquefaction. Biomass high-temperature steam liquefaction products are mainly bio-oil, while the aqueous phase byproducts of biomass hydrothermal liquefaction in this invention are aqueous phase byproducts after complete separation of bio-oil, mainly consisting of water and ketones, phenols, esters, aldehydes and carboxylic acid compounds.

[0029] The heavy oil upgrading method of this invention utilizes the aqueous byproducts of biomass hydrothermal liquefaction as the conversion water source for the hydrothermal cracking reaction of heavy oil. On the one hand, the process water (aqueous byproducts) after the biomass hydrothermal liquefaction reaction contains a large number of ketones, phenols, esters, aldehydes and carboxylic acids, which can provide active hydrogen for heavy oil upgrading. Active hydrogen can enhance the cracking depth of heavy oil and inhibit some carbon chain condensation, which is beneficial to the upgrading of oil quality. On the other hand, it can reduce the wastewater treatment cost generated when biomass hydrothermal liquefaction produces the target product bio-oil, and also reduce the water cost of heavy oil upgrading, greatly reducing the production cost. It utilizes the difficult-to-treat aqueous byproducts, making it green and environmentally friendly.

[0030] In some specific embodiments, the method for modifying heavy oil using biomass hydrothermal liquefaction aqueous phase by-products mentioned in this invention may further include the following steps: The products obtained from the hydrothermal pyrolysis reaction are allowed to stand and centrifuged to obtain an aqueous phase and an oil phase, the oil phase being the modified oil.

[0031] In some specific embodiments, the method for modifying heavy oil using biomass hydrothermal liquefaction aqueous phase by-products mentioned in this invention further includes the step of adding a catalyst to the reaction system. The catalyst includes one or more of NiO, MoO3, NiO-MoO3 / Al2O3, MoO3 / HZSM-5, Fe3O4, ZrO2, NiO-ZrO2 / HZMS-5, ZrO2 / HZSM-5, NiO-ZrO2 / Al2O3, and ZrO2-MoO3 / HZSM-5.

[0032] According to the present invention, a method for modifying heavy oil using biomass hydrothermal liquefaction aqueous phase by-products is provided. Preferably, the amount of catalyst used is 2.00 to 10.00 wt% of the heavy oil mass, for example, it can be a point value of 2 wt%, 4 wt%, 6 wt%, 8 wt%, 10 wt%, or any range thereof.

[0033] In some specific embodiments, in order to achieve better modification reaction effect, better viscosity reduction effect and modified oil quality, the catalyst mentioned in this invention is preferably NiO-MoO3 / Al2O3, and the amount of catalyst is 4wt% of heavy oil.

[0034] According to the present invention, a method for modifying heavy oil using biomass hydrothermal liquefaction aqueous by-products is provided. Preferably, the heavy oil has a dynamic viscosity of 800~13500 mPa·s at 60℃, more preferably 11000~13500 mPa·s at 60℃. For example, it can be a low-asphaltite heavy oil of 800~850 mPa·s at 60℃ or a high-viscosity heavy oil of 11000~13500 mPa·s at 60℃, or other heavy oils of different viscosities.

[0035] According to the present invention, a method for modifying heavy oil using aqueous by-products of biomass hydrothermal liquefaction is provided. Preferably, the concentration of phenolic compounds in the aqueous by-products of biomass hydrothermal liquefaction is 300 mg / L-4000 mg / L. For example, it can be point values ​​or any range of values ​​such as 300 mg / L, 500 mg / L, 800 mg / L, 900 mg / L, 1000 mg / L, 1200 mg / L, 1300 mg / L, 1500 mg / L, 2000 mg / L, 2500 mg / L, 3000 mg / L, 3500 mg / L, and 4000 mg / L.

[0036] In some specific embodiments, the aqueous by-product of biomass hydrothermal liquefaction mentioned in this invention is the aqueous by-product obtained after separating the bio-oil from the liquid product obtained by hydrothermal liquefaction reaction of lignocellulosic biomass and water.

[0037] In some specific embodiments, in order to achieve a more thorough separation of bio-oil, the separation of bio-oil from the liquid phase product mentioned in this invention is carried out by extraction. This invention does not limit the specific extractant. Any extractant in the art that can achieve the extraction and separation of bio-oil in the aqueous phase can be used. For example, the extractant includes any one of dichloromethane, ethanol, and acetone.

[0038] In some specific embodiments, the present invention further specifies the reaction conditions for the hydrothermal liquefaction reaction of lignocellulosic biomass with water to obtain the aqueous phase by-product of biomass hydrothermal liquefaction. The hydrothermal liquefaction reaction temperature is 200~320℃, the reaction time is 1~6h, and the mass ratio of lignocellulosic biomass to water is 1:5~10. For example, the specific reaction temperature can be a point value such as 200℃, 220℃, 240℃, 260℃, 280℃, 300℃, 320℃, or any range thereof. For example, the reaction time can be a point value such as 1h, 2h, 3h, 4h, 5h, 6h, or any range thereof. For example, the mass ratio of lignocellulosic biomass to water can be a point value such as 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, or any range thereof.

[0039] In specific embodiments, the present invention does not specifically limit the lignocellulosic biomass used in the hydrothermal liquefaction reaction. For example, it can be one or more of sawdust, sugarcane bagasse, sunflower seed shells, rapeseed flowers, corn stalks, barley stalks, cotton stalks, rice straw, pine wood, poplar wood, and walnut shells.

[0040] In some specific embodiments, the aqueous phase by-products of biomass hydrothermal liquefaction mentioned in this invention can be prepared by the following steps: Lignocellulose biomass is mixed with deionized water and subjected to a hydrothermal liquefaction reaction. The hydrothermal liquefaction product of the biomass is then cooled, filtered, extracted, and separated to obtain the hydrothermal liquefaction aqueous phase product.

[0041] This invention utilizes the aqueous byproducts of biomass hydrothermal liquefaction to co-hydrothermally pyrolyze heavy oil. This not only solves the environmental pollution problems caused by traditional biomass incineration but also effectively utilizes the aqueous byproducts of biomass hydrothermal liquefaction, promoting the high-value utilization of various biomass products. Furthermore, it can further reduce the viscosity and improve the quality of heavy oil. Moreover, the method of this invention is simple, requires no other energy-intensive processes, and has low temperature and pressure requirements, thus significantly reducing investment and operating costs. Example 1 A method for preparing bio-oil by hydrothermal liquefaction of biomass includes the following steps: The corn stalks were crushed and sieved using a pulverizer. The 120-mesh corn stalk particles and deionized water were placed in a sealed high-temperature and high-pressure reactor at a mass ratio of 1:10. The reactor was heated to 260°C to create a corresponding high-pressure environment, and stirred at 200 r / min for 4 hours to carry out the hydrothermal liquefaction reaction.

[0042] After the reaction is complete, the reactor is placed in cold water to cool to room temperature. The gaseous products in the reactor are first discharged. After opening the reactor, the solid-liquid mixture is transferred and filtered (using a Buchner funnel). The separated liquid phase product is extracted with dichloromethane to separate the bio-oil, yielding an aqueous byproduct (containing carboxylic acids, ketones, esters, and phenolic compounds, with the concentration of the phenolic compounds being 500 mg / L).

[0043] Example 2 A method for modifying heavy oil using biomass hydrothermal liquefaction aqueous phase byproducts includes the following steps: The aqueous phase byproducts of biomass hydrothermal liquefaction in Example 1, heavy oil, and catalyst were mixed to form a reaction system, and the heavy oil hydrothermal pyrolysis reaction was carried out in a high-temperature and high-pressure reactor.

[0044] The heavy oil is Karamay heavy oil, the catalyst is Fe3O4, and the hydrothermal pyrolysis reaction conditions are: reaction temperature 280℃, reaction time 12h, mass ratio of biomass hydrothermal liquefaction aqueous phase by-product to heavy oil 5:10, and catalyst dosage is 4.00wt% of the heavy oil mass.

[0045] After the reaction was complete, the mixture of modified oil and water was poured out and allowed to stand to separate into layers. After separation, the upper oil layer was poured into a centrifuge tube, placed in a centrifuge, and centrifuged at 4000 r / min for 10 min. The upper oil sample in the centrifuge tube was the modified oil.

[0046] Example 3 A method for preparing bio-oil by hydrothermal liquefaction of biomass includes the following steps: The sunflower seed shells were crushed and sieved using a pulverizer. The 120-mesh sunflower seed shell particles and deionized water were placed in a high-temperature and high-pressure reactor at a mass ratio of 1:6. The reactor was heated to 280°C to create a corresponding high-pressure environment, and stirred at 200 r / min for 2 hours to carry out a hydrothermal liquefaction reaction.

[0047] After the reaction is complete, the reactor is placed in cold water to cool to room temperature. The gaseous products in the reactor are first discharged. After opening the reactor, the solid-liquid mixture is transferred and filtered (using a Buchner funnel). The separated liquid product is extracted with dichloromethane to separate the bio-oil, yielding an aqueous byproduct (containing carboxylic acids, ketones, esters, and phenolic compounds, with the concentration of the phenolic compounds being 1200 mg / L).

[0048] Example 4 A method for modifying heavy oil using biomass hydrothermal liquefaction aqueous phase byproducts includes the following steps: The aqueous phase byproducts of biomass hydrothermal liquefaction in Example 3, heavy oil, and catalyst were mixed to form a reaction system, and the heavy oil hydrothermal pyrolysis reaction was carried out in a high-temperature and high-pressure reactor.

[0049] The heavy oil is Karamay heavy oil, the catalyst is ZrO2, and the hydrothermal pyrolysis reaction conditions are: reaction temperature 280℃, reaction time 12h, mass ratio of biomass hydrothermal liquefaction aqueous phase by-product to heavy oil 4:10, and catalyst dosage is 4.00wt% of the heavy oil mass.

[0050] After the reaction was complete, the mixture of modified oil and water was poured out and allowed to stand to separate into layers. After separation, the upper oil layer was poured into a centrifuge tube, placed in a centrifuge, and centrifuged at 4000 r / min for 10 min. The upper oil sample in the centrifuge tube was the modified oil.

[0051] Example 5 A method for preparing bio-oil by hydrothermal liquefaction of biomass includes the following steps: The cotton stalks were crushed and sieved using a pulverizer. The 120-mesh cotton stalk particles and deionized water were placed in a high-temperature and high-pressure reactor at a mass ratio of 1:8. The reactor was heated to 300°C to create a corresponding high-pressure environment. The mixture was stirred at 200 r / min for 2 hours to carry out the hydrothermal liquefaction reaction.

[0052] After the reaction is complete, the reactor is placed in cold water to cool to room temperature. The gaseous products in the reactor are first discharged. After opening the reactor, the solid-liquid mixture is transferred and filtered (using a Buchner funnel). The separated liquid product is extracted with dichloromethane to separate the bio-oil, yielding an aqueous byproduct (containing carboxylic acids, ketones, esters, and phenolic compounds, with the concentration of the phenolic compounds being 1300 mg / L).

[0053] Example 6 A method for modifying heavy oil using biomass hydrothermal liquefaction aqueous phase byproducts includes the following steps: The aqueous byproducts of biomass hydrothermal liquefaction in Example 5, heavy oil, and catalyst were mixed to form a reaction system, which was then placed in a high-temperature and high-pressure reactor for hydrothermal cracking of the heavy oil.

[0054] The heavy oil is Karamay heavy oil, the catalyst is NiO-MoO3 / Al2O3, and the hydrothermal pyrolysis reaction conditions are: reaction temperature 300℃, reaction time 18h, the mass ratio of biomass hydrothermal liquefaction aqueous phase by-product to heavy oil is 5:10, and the catalyst dosage is 4.00wt% of the heavy oil mass.

[0055] After the reaction was complete, the mixture of modified oil and water was poured out and allowed to stand to separate into layers. After separation, the upper oil layer was poured into a centrifuge tube, placed in a centrifuge, and centrifuged at 4000 r / min for 10 min. The upper oil sample in the centrifuge tube was the modified oil.

[0056] Example 7 A method for preparing bio-oil by hydrothermal liquefaction of biomass includes the following steps: The walnut shells were crushed and sieved using a pulverizer. The 120-mesh walnut shell particles and deionized water were placed in a high-temperature and high-pressure reactor at a mass ratio of 1:5. The reactor was heated to 240°C to create a corresponding high-pressure environment. The mixture was stirred at 200 r / min for 6 hours to carry out a hydrothermal liquefaction reaction.

[0057] After the reaction is complete, the reactor is placed in cold water to cool to room temperature. The gaseous products in the reactor are first discharged. After opening the reactor, the solid-liquid mixture is transferred and filtered (using a Buchner funnel). The separated liquid product is extracted with dichloromethane to separate the bio-oil, yielding an aqueous byproduct (containing carboxylic acids, ketones, esters, and phenolic compounds, with the concentration of the phenolic compounds being 900 mg / L).

[0058] Example 8 A method for modifying heavy oil using biomass hydrothermal liquefaction aqueous phase byproducts includes the following steps: The aqueous byproducts of biomass hydrothermal liquefaction in Example 7, heavy oil, and catalyst were mixed to form a reaction system, which was then placed in a high-temperature and high-pressure reactor for hydrothermal cracking of the heavy oil.

[0059] The heavy oil is Karamay heavy oil, the catalyst is NiO-ZrO2 / Al2O3, and the hydrothermal pyrolysis reaction conditions are: reaction temperature 260℃, reaction time 24h, the mass ratio of biomass hydrothermal liquefaction aqueous phase by-product to heavy oil is 8:10, and the catalyst dosage is 4.00wt% of the heavy oil mass.

[0060] After the reaction was complete, the mixture of modified oil and water was poured out and allowed to stand to separate into layers. After separation, the upper oil layer was poured into a centrifuge tube, placed in a centrifuge, and centrifuged at 4000 r / min for 10 min. The upper oil sample in the centrifuge tube was the modified oil.

[0061] Example 9 A method for modifying heavy oil using biomass hydrothermal liquefaction aqueous phase byproducts includes the following steps: The aqueous byproducts of biomass hydrothermal liquefaction in Example 5, heavy oil, and catalyst were mixed to form a reaction system, which was then placed in a high-temperature and high-pressure reactor for hydrothermal cracking of the heavy oil.

[0062] The heavy oil is from Karamay District 9, the catalyst is NiO-MoO3 / Al2O3, and the hydrothermal pyrolysis reaction conditions are: reaction temperature 300℃, reaction time 18h, mass ratio of biomass hydrothermal liquefaction aqueous phase by-product to heavy oil 5:10, and catalyst dosage is 4.00wt% of the heavy oil mass.

[0063] After the reaction was complete, the mixture of modified oil and water was poured out and allowed to stand to separate into layers. After separation, the upper oil layer was poured into a centrifuge tube, placed in a centrifuge, and centrifuged at 4000 r / min for 10 min. The upper oil sample in the centrifuge tube was the modified oil.

[0064] Comparative Example 1 A method for modifying heavy oil using biomass hydrothermal liquefaction aqueous phase byproducts includes the following steps: Water, heavy oil, and catalyst are mixed to form a reaction system, which is then placed in a high-temperature, high-pressure reactor to carry out the hydrothermal cracking reaction of the heavy oil.

[0065] The heavy oil was Karamay heavy oil, the catalyst was Fe3O4, and the hydrothermal cracking reaction conditions were: reaction temperature 280℃, reaction time 12h, water to heavy oil mass ratio of 5:10, and catalyst dosage of 4.00wt% of heavy oil mass.

[0066] After the reaction was complete, the mixture of modified oil and water was poured out and allowed to stand to separate into layers. After separation, the upper oil layer was poured into a centrifuge tube, placed in a centrifuge, and centrifuged at 4000 r / min for 10 min. The upper oil sample in the centrifuge tube was the modified oil.

[0067] Comparative Example 2 A method for modifying heavy oil using biomass hydrothermal liquefaction aqueous phase byproducts includes the following steps: Water, heavy oil, and catalyst are mixed to form a reaction system, which is then placed in a high-temperature, high-pressure reactor to carry out the hydrothermal cracking reaction of the heavy oil.

[0068] The heavy oil is Karamay heavy oil, the catalyst is ZrO2, and the hydrothermal cracking reaction conditions are: reaction temperature 280℃, reaction time 12h, water to heavy oil mass ratio of 4:10, and catalyst dosage of 4.00wt% of heavy oil mass.

[0069] After the reaction was complete, the mixture of modified oil and water was poured out and allowed to stand to separate into layers. After separation, the upper oil layer was poured into a centrifuge tube, placed in a centrifuge, and centrifuged at 4000 r / min for 10 min. The upper oil sample in the centrifuge tube was the modified oil.

[0070] Comparative Example 3 A method for modifying heavy oil using biomass hydrothermal liquefaction aqueous phase byproducts includes the following steps: Water, heavy oil, and catalyst are mixed to form a reaction system, which is then placed in a high-temperature, high-pressure reactor to carry out the hydrothermal cracking reaction of the heavy oil.

[0071] The heavy oil is Karamay heavy oil, the catalyst is NiO-MoO3 / Al2O3, and the hydrothermal cracking reaction conditions are: reaction temperature 300℃, reaction time 18h, water to heavy oil mass ratio of 5:10, and catalyst dosage of 4.00wt% of heavy oil mass.

[0072] After the reaction was complete, the mixture of modified oil and water was poured out and allowed to stand to separate into layers. After separation, the upper oil layer was poured into a centrifuge tube, placed in a centrifuge, and centrifuged at 4000 r / min for 10 min. The upper oil sample in the centrifuge tube was the modified oil.

[0073] Comparative Example 4 A method for modifying heavy oil using biomass hydrothermal liquefaction aqueous phase byproducts includes the following steps: Water, heavy oil, and catalyst are mixed to form a reaction system, which is then placed in a high-temperature, high-pressure reactor to carry out the hydrothermal cracking reaction of the heavy oil.

[0074] The heavy oil is Karamay heavy oil, the catalyst is NiO-ZrO2 / Al2O3, and the hydrothermal pyrolysis reaction conditions are: reaction temperature 260℃, reaction time 12h, the mass ratio of biomass hydrothermal liquefaction aqueous phase by-product to heavy oil is 1:1, and the catalyst dosage is 4.00wt% of the heavy oil mass.

[0075] After the reaction was complete, the mixture of modified oil and water was poured out and allowed to stand to separate into layers. After separation, the upper oil layer was poured into a centrifuge tube, placed in a centrifuge, and centrifuged at 4000 r / min for 10 min. The upper oil sample in the centrifuge tube was the modified oil.

[0076] Comparative Example 5 A method for modifying heavy oil using biomass hydrothermal liquefaction aqueous phase byproducts includes the following steps: Water, heavy oil, and catalyst are mixed to form a reaction system, which is then placed in a high-temperature, high-pressure reactor to carry out the hydrothermal cracking reaction of the heavy oil.

[0077] The heavy oil is from Karamay District 9, the catalyst is NiO-MoO3 / Al2O3, and the hydrothermal cracking reaction conditions are: reaction temperature 300℃, reaction time 18h, water to heavy oil mass ratio of 5:10, and catalyst dosage of 4.00wt% of heavy oil mass.

[0078] After the reaction was complete, the mixture of modified oil and water was poured out and allowed to stand to separate into layers. After separation, the upper oil layer was poured into a centrifuge tube, placed in a centrifuge, and centrifuged at 4000 r / min for 10 min. The upper oil sample in the centrifuge tube was the modified oil.

[0079] Result detection The dynamic viscosity of the modified oils in the examples and comparative examples was tested, and their group composition was analyzed. The specific results are shown in Table 3 below.

[0080] Table 3. Comparison of Heavy Oil Modification Effects

[0081] The standard for determining the composition of heavy oil is SY / T5119-2016.

[0082] As shown in Table 3, the viscosity reduction rate of heavy oil before and after modification in the embodiments of the present invention can reach up to 90.27%, which is a significant improvement compared to the 52.34% achieved by conventional hydrothermal decomposition. Furthermore, compositional analysis shows that the modification method in the embodiments of the present invention significantly increases the content of saturated components, thereby improving the quality of the modified oil.

[0083] The heavy oil from Karamay District 9 used in Example 9 of this invention is a low-asphaltene heavy oil with an asphaltene content of less than 1%. Its viscosity reduction rate is significantly lower than other heavy oils, generally 30% or less. As shown in Table 3, the viscosity reduction rate of the heavy oil in Example 9 of this invention before and after modification can reach up to 57.36%, which is a significant improvement compared to the 31.49% achieved by conventional hydrothermal decomposition. Furthermore, compositional analysis shows that the modification method in this embodiment significantly increases the saturated fraction content, thereby improving the quality of the modified oil.

[0084] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for modifying heavy oil using biomass hydrothermal liquefaction aqueous phase by-products, characterized in that, The process includes the following steps: mixing the aqueous phase by-products of biomass hydrothermal liquefaction with heavy oil to form a reaction system, and carrying out a hydrothermal pyrolysis reaction to obtain modified oil. The mass ratio of the aqueous phase by-products of biomass hydrothermal liquefaction to heavy oil is 3~8:10, and the hydrothermal pyrolysis reaction temperature is 200~320℃, and the time is 6~30h.

2. The method for modifying heavy oil using biomass hydrothermal liquefaction aqueous phase by-products according to claim 1, characterized in that, The reaction system also includes the step of adding a catalyst to the reaction system, the catalyst comprising one or more of NiO, MoO3, NiO-MoO3 / Al2O3, MoO3 / HZSM-5, Fe3O4, ZrO2, NiO-ZrO2 / HZMS-5, ZrO2 / HZSM-5, NiO-ZrO2 / Al2O3, and ZrO2-MoO3 / HZSM-5.

3. The method for modifying heavy oil using biomass hydrothermal liquefaction aqueous phase by-products according to claim 2, characterized in that, The catalyst is used in an amount of 2.00 to 10.00 wt% of the heavy oil.

4. The method for modifying heavy oil using biomass hydrothermal liquefaction aqueous phase by-products according to claim 3, characterized in that, The catalyst is NiO-MoO3 / Al2O3, and the amount of catalyst used is 4 wt% of the heavy oil.

5. The method for modifying heavy oil using biomass hydrothermal liquefaction aqueous phase by-products according to any one of claims 1 to 4, characterized in that, The dynamic viscosity of the heavy oil is 800~13500 mPa·s at 60℃.

6. The method for modifying heavy oil using biomass hydrothermal liquefaction aqueous phase by-products according to any one of claims 1 to 4, characterized in that, The concentration of phenolic compounds in the aqueous phase byproducts of the biomass hydrothermal liquefaction is 300 mg / L-4000 mg / L.

7. The method for modifying heavy oil using biomass hydrothermal liquefaction aqueous phase by-products according to claim 6, characterized in that, The aqueous by-product of biomass hydrothermal liquefaction is the aqueous by-product obtained after separating the bio-oil from the liquid product obtained by hydrothermal liquefaction of lignocellulosic biomass and water.

8. The method for modifying heavy oil using biomass hydrothermal liquefaction aqueous phase by-products according to claim 7, characterized in that, The liquid-phase product is separated into bio-oils through extraction, with the extractant including any one of dichloromethane, ethanol, and acetone.

9. The method for modifying heavy oil using biomass hydrothermal liquefaction aqueous phase by-products according to claim 8, characterized in that, The hydrothermal liquefaction reaction is carried out at a temperature of 200-320℃ for 1-6 hours, and the mass ratio of lignocellulose biomass to water is 1:5-10.

10. The method for modifying heavy oil using aqueous by-products of biomass hydrothermal liquefaction according to any one of claims 7 to 9, characterized in that, The lignocellulosic biomass includes one or more of the following: sawdust, sugarcane bagasse, sunflower seed shells, rapeseed flowers, corn stalks, barley stalks, cotton stalks, rice straw, pine wood, poplar wood, and walnut shells.

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