Preparation method and application of nano metal oxide catalyst
The nanometal oxide catalyst was synthesized by hydrothermal method, which solved the problems of poor fluidity of heavy oil and wastewater resource utilization, and achieved efficient viscosity reduction of heavy oil and wastewater resource recovery, with the catalyst viscosity reduction rate reaching 76.3%.
Patent Information
- Application Number
- CN202410969329.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-19
- Publication Date
- 2025-08-19
- Estimated Expiration
- 2044-07-19
AI Technical Summary
The high viscosity of heavy oil leads to poor fluidity, the existing chemical modification and viscosity reduction methods are costly and the catalyst utilization is not efficient enough, and the metal ions in industrial wastewater have not been effectively recycled.
The nanometal oxide catalyst was synthesized using hydrothermal method using industrial wastewater as solvent, iron salt and sodium hydroxide, and treated with oil-soluble modifiers to prepare a regular morphological nanometal oxide catalyst.
The prepared nanometal oxide catalyst has significant viscosity reduction effect in heavy oil, has the advantages of environmental protection and resource reuse, and is easy to operate, has stable catalytic activity, and has a viscosity reduction rate of up to 76.3%.
Smart Images
Figure CN118904353B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of crude oil catalysis, and in particular to a preparation method and application of a nano metal oxide catalyst. Background Art
[0002] With the rapid growth of oil consumption, conventional oil supply is gradually outstripping demand. Heavy oil (API gravity <22, viscosity >100 mPa·s) is an unconventional oil, but it holds excellent development prospects. Furthermore, heavy oil accounts for approximately 70% of total oil reserves. Effectively utilizing heavy oil could effectively address the shortage of oil resources. However, heavy oil's high viscosity, resulting in poor fluidity, presents significant challenges in its extraction. Over the past few decades, intensive research has been conducted on various approaches to improving the fluidity of heavy oil. The main methods for heavy oil extraction include physical methods (such as thermal recovery and steam stimulation) and chemical methods (reservoir combustion and activated water viscosity reduction). Thermal recovery is the primary method for reducing heavy oil viscosity during extraction, but it carries high investment costs. In recent years, chemical modification and viscosity reduction have made significant progress. Catalysts and hydrogen donors are added to the reservoir, and heavy oil undergoes hydrothermal cracking under high temperature, high pressure, and the presence of a catalyst. During the reaction, the catalyst effectively promotes the decomposition of long molecular chains into free radical fragments. Some of these are quenched to form shorter molecules, while others undergo copolymerization. The former reaction is beneficial for viscosity reduction, while the latter is detrimental. The addition of hydrogen donors provides a large number of hydrogen radicals, which help quench the free radical fragments produced by hydrothermal cracking and inhibit their copolymerization, thereby increasing the viscosity reduction rate. Heavy oil hydrothermal cracking catalysts can be broadly categorized by their properties, including mineral-based, water-soluble, oil-soluble, amphiphilic, and dispersed heterogeneous catalysts.
[0003] Industrial wastewater contains a high concentration of metal ions, which, when discharged directly, can cause serious environmental harm. However, the metal ions can be recycled and used to synthesize heavy oil viscosity-reducing catalysts. This research has important implications for wastewater recycling and the synthesis of heavy oil viscosity-reducing catalysts. Summary of the Invention
[0004] In order to solve the above technical problems, embodiments of the present invention provide a preparation method and application of a nano metal oxide catalyst.
[0005] To achieve the above objectives, the embodiments of the present invention adopt the following technical solutions:
[0006] In one aspect, the present invention provides a method for preparing a nano-metal oxide catalyst, comprising the following steps:
[0007] A. dissolving an iron salt in waste water to obtain an iron salt solution, dissolving sodium hydroxide in the waste water to obtain a sodium hydroxide solution, and then dropwise adding the iron salt solution to the sodium hydroxide solution to mix to obtain a mixed solution;
[0008] B. subjecting the mixed solution of step A to a hydrothermal reaction, centrifuging the reacted material, collecting the precipitate, washing and drying it to obtain a nano-metal oxide catalyst precursor;
[0009] C. Add the nano metal oxide catalyst precursor in step B to the oil-soluble modifier, centrifuge after the reaction, collect the precipitate, and dry to obtain the nano metal oxide catalyst.
[0010] In some embodiments, in step A, the iron salt includes at least one of ferric chloride hexahydrate, ferric nitrate nonahydrate, and ferric sulfate.
[0011] In some embodiments, in step A, the mass ratio of the iron salt to the wastewater is (0.01-0.05):1.
[0012] In some embodiments, in step A, the molar ratio of sodium hydroxide to iron salt is 3:1.
[0013] In some embodiments, in step B, the temperature of the hydrothermal reaction is 140°C to 200°C.
[0014] In some embodiments, in step B, the hydrothermal reaction time is 6 to 16 hours.
[0015] In some embodiments, in step C, the oil-soluble modifier is oleic acid or oleylamine.
[0016] In some embodiments, in step C, the mass ratio of the oil-soluble modifier to the nano metal oxide catalyst precursor is 1:1 to 3:1.
[0017] On the other hand, the present invention provides an application of a nano metal oxide catalyst prepared by the above preparation method in reducing the viscosity of heavy oil.
[0018] Compared with the prior art, the present invention has at least the following beneficial effects:
[0019] (1) The present invention uses industrial wastewater as a solvent, iron salts and sodium hydroxide to synthesize nano-metal oxides by a hydrothermal method. The nano-metal oxides prepared by the present invention can reach a size of 50 nm, have a narrow size distribution, and are regular polygonal in shape. The nanoparticles have excellent activity in the hydrothermal cracking and upgrading of heavy oil, and the regular morphology enables the catalyst performance to be kept stable during the catalytic reaction, so that the catalyst always maintains high catalytic activity. The nano-metal oxides prepared by the present invention are applied to heavy oil viscosity reduction and have excellent viscosity reduction effect.
[0020] (2) The present invention uses industrial wastewater containing metal ions to prepare nano-metal oxides, and recycles the wastewater, which is of great significance for environmental protection, resource recycling, and reduction of economic losses, and the operation is convenient and controllable. In addition, the nano-metal oxides prepared by the present invention have Fe2O3 as the main component and contain SiO2, CaO, MgO, MnO and other components. Compared with the existing nano-Fe2O3, they have a smaller particle size and a more regular morphology, thereby improving their catalytic activity in the hydrothermal reforming of heavy oil.
[0021] (3) The preparation method of the present invention is simple, and only requires generating nano-metal oxides by a hydrothermal method, and then performing a step of modification and drying. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 is the X-ray diffraction pattern of the nano metal oxide obtained in Comparative Example 1;
[0023] Figure 2 This is a scanning electron microscope image (SEM image) of the nano-metal oxide obtained in Comparative Example 1;
[0024] Figure 3 is a particle size distribution diagram of the nano metal oxide obtained in Comparative Example 1;
[0025] Figure 4 is the X-ray diffraction pattern of the nano metal oxide obtained in Comparative Example 2;
[0026] Figure 5 This is the SEM image of the nano-metal oxide obtained in Comparative Example 2;
[0027] Figure 6 is the X-ray diffraction pattern of the nano metal oxide obtained in Example 1;
[0028] Figure 7 is the X-ray diffraction pattern of the nano-metal oxide obtained in Example 2;
[0029] Figure 8 This is the SEM image of the commercial iron oxide used in Comparative Example 1. DETAILED DESCRIPTION
[0030] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in some embodiments of the present disclosure. Obviously, the embodiments described are only some embodiments of the present disclosure, not all embodiments. Based on the embodiments provided by the present disclosure, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of the present disclosure.
[0031] In one aspect, the present invention provides a method for preparing a nano-metal oxide catalyst, comprising the following steps:
[0032] A. Dissolving an iron salt in wastewater to obtain an iron salt solution, dissolving sodium hydroxide in the wastewater to obtain a sodium hydroxide solution, and then adding the iron salt solution dropwise to the sodium hydroxide solution to mix to obtain a mixed solution. The wastewater is industrial wastewater containing ions such as calcium, silicon, magnesium, manganese, and iron;
[0033] B. subjecting the mixed solution of step A to a hydrothermal reaction, centrifuging the reacted material, collecting the precipitate, washing and drying it to obtain a nano-metal oxide catalyst precursor;
[0034] C. Add the nano metal oxide catalyst precursor in step B to the oil-soluble modifier, centrifuge after the reaction, collect the precipitate, and dry to obtain the nano metal oxide catalyst.
[0035] In some embodiments, in step A, the iron salt includes at least one of ferric chloride hexahydrate, ferric nitrate nonahydrate, and ferric sulfate.
[0036] In some embodiments, in step A, the mass ratio of the iron salt to the wastewater is (0.01-0.05):1, illustratively, it can be 0.01:1, 0.02:1, 0.03:1, 0.04:1 or 0.05:1.
[0037] In some embodiments, in step A, the molar ratio of sodium hydroxide to iron salt is 3:1.
[0038] In some embodiments, in step B, the temperature of the hydrothermal reaction is 140°C to 200°C, and illustratively, can be 140°C, 160°C, 180°C, or 200°C.
[0039] In some embodiments, in step B, the hydrothermal reaction time is 6 to 16 hours, and illustratively, it can be 6 hours, 8 hours, 10 hours, 12 hours, 14 hours, or 16 hours.
[0040] In some embodiments, in step C, the oil-soluble modifier is oleic acid or oleylamine.
[0041] In some embodiments, in step C, the mass ratio of the oil-soluble modifier to the nano-metal oxide catalyst precursor is 1:1 to 3:1, and illustratively, can be 1:1, 2:1 or 3:1.
[0042] On the other hand, the present invention provides an application of a nano metal oxide catalyst prepared by the above preparation method in reducing the viscosity of heavy oil.
[0043] Specifically, heavy oil is placed in a reactor, water is added at an oil-water ratio of 1:1, and a nano-metal oxide catalyst is added to the reactor, hydrothermal catalytic cracking is carried out at a certain temperature, the reaction is carried out for a certain time, and then the oil sample after the reaction is taken out to measure the viscosity and SARA; in the present invention, the hydrothermal catalytic cracking reaction is carried out at 180-260°C (for example, 180°C, 200°C, 220°C, 240°C, 260°C) for 8-24h (for example, 8h, 12h, 16h, 20h, 24h); in the present invention, the mass ratio of the nano-metal oxide catalyst to the heavy oil is 0.005:1.
[0044] The present invention uses industrial wastewater as a solvent, iron salts and sodium hydroxide to synthesize nano-metal oxides through a hydrothermal method. The nano-metal oxides prepared by the present invention can reach a size of 50 nm, have a narrow size distribution, and are regular polygonal shapes. The nano-metal oxides prepared by the present invention are used for reducing the viscosity of heavy oil and have excellent viscosity reducing effects.
[0045] Example 1
[0046] Industrial wastewater (the composition of which is shown in Table 1) was taken. 1g of FeCl₃·6H₂O and 0.45g of NaOH were dissolved in 20mL of wastewater. After complete dissolution, the two were mixed and stirred evenly. The mixture was then added to a polytetrafluoroethylene-lined stainless steel hydrothermal reactor, which was placed in an oven and reacted at 160°C for 12 hours. The resulting precipitate was collected using a centrifuge at 12,500 r / min and washed several times with pure water. The solid was then dried in an oven at 60°C for 12 hours to obtain a powder, the nanometal oxide catalyst precursor. 0.07g of oleic acid was dissolved in 30mL of methanol, and 0.07g of the nanometal oxide catalyst precursor obtained in the above step was added. The mixture was stirred at room temperature for 1 hour. The resulting precipitate was collected using a centrifuge at 12,500 r / min and dried in a vacuum oven at 60°C for 12 hours to obtain the nanometal oxide catalyst. The components of the nano metal oxide catalyst are: 93.6wt% Fe2O3; 1.5wt% CaO; 0.9wt% SiO2; 0.8wt% MgO; 0.3wt% MnO; the remainder is organic matter and inevitable impurities that are difficult to detect.
[0047] Example 2
[0048] Industrial wastewater (the main components of which are shown in Table 1) was taken. 1g of FeCl3·6H2O and 0.45g of NaOH were dissolved in 20mL of wastewater. After complete dissolution, the two solutions were mixed and added to a polytetrafluoroethylene-lined stainless steel hydrothermal reactor. The reactor was placed in an oven and reacted at 160°C for 12 hours. The precipitate was collected by centrifuge at 12,500 rpm and washed several times with pure water. The solid was then dried in an oven at 60°C for 12 hours to obtain a powder, which was the nanometal oxide catalyst precursor. 0.07g of oleylamine was dissolved in 30ml of methanol, and 0.07g of the nanometal oxide catalyst precursor obtained in the above step was added. The mixture was stirred at room temperature for 1 hour. The precipitate was collected by centrifuge at 12,500 rpm and dried in a vacuum oven at 60°C for 12 hours to obtain the nanometal oxide catalyst. The components of the nano metal oxide catalyst are: Fe2O3 is 92.8wt%; CaO is 1.6wt%; SiO2 is 0.8wt%; MgO is 0.6wt%; MnO is 0.2wt%; the remainder is organic matter that is difficult to detect and inevitable impurities.
[0049] The X-ray diffraction pattern of the nano-metal oxide catalyst obtained in Example 2 is as follows: Figure 7 As shown in the X-ray diffraction patterns, the 2θ peaks are located at 24.1°, 33.1°, 35.6°, 40.8°, 49.4°, 54.1°, 57.6°, 62.4°, and 64.0°, respectively, belonging to the (012), (104), (110), (113), (024), (116), (018), (214), and (300) crystal planes, respectively. The synthesis is a nano-metal oxide catalyst with α-Fe2O3 as the main component. However, compared with the X-ray diffraction patterns of Comparative Examples 1 and 2, the peak intensity is significantly weakened, and a carbon-related peak appears at 26.0°, proving that oleylamine has effectively modified the nano-metal oxide catalyst.
[0050] Comparative Example 1
[0051] Industrial wastewater (the main components of which are shown in Table 1) was taken. 1g of FeCl3·6H2O and 0.45g of NaOH were dissolved in 20mL of wastewater. After complete dissolution, the two were mixed and stirred evenly. The mixture was then added to a polytetrafluoroethylene-lined stainless steel hydrothermal reactor, which was placed in an oven and reacted at 160°C for 12 hours. The precipitate was collected using a centrifuge at 12,500 rpm and washed several times with pure water. The solid was then dried in an oven at 60°C for 12 hours. The resulting powder was a nanometal oxide catalyst composed of 94wt% Fe2O3, 1.6wt% CaO, 1.1wt% SiO2, 0.6wt% MgO, and 0.4wt% MnO. The remainder was unavoidable impurities.
[0052] The X-ray diffraction pattern of the nano metal oxide catalyst obtained in this comparative example 1 is as follows Figure 1 As shown, the 2θ peaks are located at 24.1°, 33.1°, 35.6°, 40.8°, 49.4°, 54.1°, 57.6°, 62.4° and 64.0°, respectively, belonging to the (012), (104), (110), (113), (024), (116), (018), (214) and (300) crystal planes, respectively. The synthesis is a nano-metal oxide catalyst with α-Fe2O3 as the main component. The SEM image of the nano-metal oxide catalyst synthesized in this comparative example 1 is shown in FIG. Figure 2 As shown, from Figure 2 It can be seen that most of the nanoparticles are regular polyhedrons, and a small number are spherical. Figure 3 It can be seen that the particle size distribution is narrow, mainly concentrated between 30 and 60 nm.
[0053] Comparative Example 2
[0054] Industrial wastewater (the composition of which is shown in Table 1) was prepared. 1g of FeCl3·6H2O and 0.45g of NaOH were dissolved in 20mL of wastewater. After complete dissolution, the two were mixed and stirred evenly. The mixture was then added to a polytetrafluoroethylene-lined stainless steel hydrothermal reactor, which was placed in an oven and reacted at 200°C for 12 hours. The precipitate was collected using a centrifuge at 12,500 rpm and washed several times with pure water. The solid was then dried in an oven at 60°C for 12 hours. The resulting powder was a nanometal oxide catalyst composed of 94wt% Fe2O3, 1.4wt% CaO, 1.2wt% SiO2, 1.0wt% MgO, and 0.5wt% MnO. The remainder was unavoidable impurities.
[0055] The X-ray diffraction pattern of the nano metal oxide catalyst obtained in this comparative example 2 is as follows: Figure 4 As shown, the 2θ peaks are located at 24.1°, 33.1°, 35.6°, 40.8°, 49.4°, 54.1°, 57.6°, 62.4° and 64.0°, respectively, belonging to the (012), (104), (110), (113), (024), (116), (018), (214) and (300) crystal planes, respectively. The synthesis is a nano-metal oxide catalyst with α-Fe2O3 as the main component. The SEM image of the nano-metal oxide synthesized in this comparative example 2 is shown in FIG. Figure 5 As shown, from Figure 5 It can be seen that the nanoparticles are in the shape of a round cake with a length of 140nm and a width of 50nm, and the particle size distribution of the catalyst is mainly concentrated between 120 and 160nm.
[0056] In summary, the X-ray diffraction pattern of the nano-metal oxide catalyst obtained in this Example 1 is as follows: Figure 6 As shown in the X-ray diffraction patterns of Comparative Examples 1 and 2, the 2θ peaks are located at 24.1°, 33.1°, 35.6°, 40.8°, 49.4°, 54.1°, 57.6°, 62.4° and 64.0°, respectively, belonging to the (012), (104), (110), (113), (024), (116), (018), (214) and (300) crystal planes, respectively. The synthesis is a nano-metal oxide catalyst with α-Fe2O3 as the main component. However, compared with the X-ray diffraction patterns of Comparative Examples 1 and 2, the peak intensity is significantly weakened, and a carbon-related peak appears at 26.0°, proving that oleic acid has effectively modified the nano-metal oxide catalyst. The components of the industrial wastewater mentioned above are shown in Table 1 below:
[0057] Table 1
[0058]
[0059]
[0060] Application Example 1
[0061] 80g of heavy oil was placed in a 500mL reactor. Water was added at a 1:1 oil-water ratio, and the nano-metal oxide catalyst from Comparative Example 1 was added at a 1:0.005 weight ratio of heavy oil to catalyst. The reactor was heated to 240°C and stirred at 350 rpm for 24 hours. After the reaction, an oil sample was removed from the reactor and its post-reaction viscosity was measured using a viscometer at 50°C. During the measurement, the torque was maintained between 30% and 70%. The sample was then analyzed for changes in SRAR components.
[0062] The viscosity reduction rate (Δη) of heavy oil viscosity reduction catalyst is calculated by the following formula:
[0063]
[0064] Where η0 is the viscosity before reaction and η is the viscosity after reaction.
[0065] The crude oil used in Application Example 1 was 41,000 mPa·s Tuha heavy oil. After the reaction, the viscosity was reduced to 12,067 mPa·s, and the viscosity reduction rate reached 70.57%. The SARA results are shown in Table 2. It can be seen that after the reaction, the saturates and aromatics of the oil sample were significantly increased, the resin content was significantly reduced, and the asphaltenes were also reduced to a certain extent. This is consistent with the results of viscosity reduction and has a good viscosity reduction effect.
[0066] Application Example 2
[0067] 80g of heavy oil was placed in a 500mL reactor. Water was added at a 1:1 oil-water ratio, and the nano-metal oxide catalyst from Comparative Example 1 was added at a 1:0.005 weight ratio of heavy oil to catalyst. The reactor was heated to 220°C and stirred at 350 rpm for 24 hours. After the reaction, an oil sample was removed from the reactor and its post-reaction viscosity was measured using a viscometer at 50°C. During the measurement, the torque was maintained between 30% and 70%. The sample was then analyzed for changes in SRAR components.
[0068] The viscosity reduction rate (Δη) of heavy oil viscosity reduction catalyst is calculated by the following formula:
[0069]
[0070] Where η0 is the viscosity before reaction and η is the viscosity after reaction.
[0071] The crude oil used in Application Example 2 was 41,000 mPa·s Tuha heavy oil. After the reaction, the viscosity was reduced to 14,830 mPa·s, and the viscosity reduction rate reached 63.83%. The SARA results are shown in Table 2. It can be seen that after the reaction, the saturates and aromatics of the oil sample increased, the colloid content decreased, but the asphaltenes did not decrease significantly. The temperature reduction is not conducive to the catalytic viscosity reduction effect of the nano-metal oxide catalyst.
[0072] Application Example 3
[0073] 80g of heavy oil was placed in a 500mL reactor. Water was added at a 1:1 oil-water ratio, and the nano-metal oxide catalyst from Comparative Example 1 was added at a 1:0.005 weight ratio of heavy oil to catalyst. The reactor was heated to 260°C and stirred at 350 rpm for 24 hours. After the reaction, an oil sample was removed from the reactor and its post-reaction viscosity was measured using a viscometer at 50°C. During the measurement, the torque was maintained between 30% and 70%. The sample was then analyzed for changes in SRAR components.
[0074] The viscosity reduction rate (Δη) of heavy oil viscosity reduction catalyst is calculated by the following formula:
[0075]
[0076] Where η0 is the viscosity before reaction and η is the viscosity after reaction.
[0077] The crude oil used in Application Example 3 was 41,000 mPa·s Tuha heavy oil. After the reaction, the viscosity was reduced to 10,856 mPa·s, and the viscosity reduction rate reached 73.52%. The SARA results are shown in Table 2. It can be seen that after the reaction, the saturates and aromatics of the oil sample were greatly increased, and the colloids and asphaltenes were also greatly reduced. The increase in reaction temperature is conducive to the catalytic viscosity reduction effect of the nano-metal oxide catalyst.
[0078] Application Example 4
[0079] 80g of heavy oil was placed in a 500mL reactor. Water was added at a 1:1 oil-water ratio, and the nano-metal oxide catalyst from Comparative Example 2 was added at a 1:0.005 weight ratio of heavy oil to catalyst. The reactor was heated to 240°C and stirred at 350 rpm for 24 hours. After the reaction, an oil sample was removed from the reactor and its post-reaction viscosity was measured using a viscometer at 50°C. During the measurement, the torque was maintained between 30% and 70%. The sample was then analyzed for changes in SRAR components.
[0080] The viscosity reduction rate (Δη) of heavy oil viscosity reduction catalyst is calculated by the following formula:
[0081]
[0082] Where η0 is the viscosity before reaction and η is the viscosity after reaction.
[0083] The crude oil used in Application Example 4 was Tuha heavy oil with a viscosity of 41,000 mPa·s. After the reaction, the viscosity was reduced to 14,227 mPa·s, and the viscosity reduction rate reached 65.3%. The SARA results are shown in Table 2. It can be seen that after the reaction, the saturates and aromatics of the oil sample increased, the colloids decreased, but the asphaltenes did not decrease significantly. This indicates that the catalytic viscosity reduction effect of the nano-metal oxide catalyst prepared from wastewater decreases with the increase in size.
[0084] Application Example 5
[0085] 80g of heavy oil was placed in a 500mL reactor. Water was added at a 1:1 oil / water ratio, and the nano-metal oxide catalyst described in Example 1 was added at a 1:0.005 weight ratio of heavy oil to catalyst. The reactor was heated to 240°C and stirred at 350 rpm for 24 hours. After the reaction, an oil sample was removed from the reactor and its post-reaction viscosity was measured using a viscometer at 50°C. During the measurement, the torque was maintained between 30% and 70%. The sample was then analyzed for changes in SRAR components.
[0086] The viscosity reduction rate (Δη) of heavy oil viscosity reduction catalyst is calculated by the following formula:
[0087]
[0088] Where η0 is the viscosity before reaction and η is the viscosity after reaction.
[0089] The crude oil used in Application Example 5 was 41,000 mPa·s Tuha heavy oil. After the reaction, the viscosity was reduced to 9,717 mPa·s, and the viscosity reduction rate reached 76.3%. The SARA results are shown in Table 2. It can be seen that after the reaction, the saturates and aromatics of the oil sample were greatly increased, and the colloids and asphaltenes were also greatly reduced. The nano-metal oxide modified with oleic acid becomes an oil-soluble catalyst, making it easier to disperse in the oil, thereby improving its catalytic viscosity reduction effect on heavy oil.
[0090] Application Example 6
[0091] 80g of heavy oil was placed in a 500mL reactor. Water was added at a 1:1 oil / water ratio, and the nano-metal oxide catalyst described in Example 2 was added at a 1:0.005 weight ratio of heavy oil to catalyst. The reactor was heated to 240°C and stirred at 350 rpm for 24 hours. After the reaction, an oil sample was removed from the reactor and its post-reaction viscosity was measured using a viscometer at 50°C. During the measurement, the torque was maintained between 30% and 70%. The sample was then analyzed for changes in SRAR components.
[0092] The viscosity reduction rate (Δη) of heavy oil viscosity reduction catalyst is calculated by the following formula:
[0093]
[0094] Where η0 is the viscosity before reaction and η is the viscosity after reaction.
[0095] The crude oil used in this application example was Tuha heavy oil with a viscosity of 41,000 mPa·s. After the reaction, the viscosity was reduced to 10,170 mPa·s, and the viscosity reduction rate reached 75.19%. The SARA results are shown in Table 2. The nano-metal oxide modified with oleylamine becomes an oil-soluble catalyst, making it easier to disperse in the oil, thereby improving its catalytic viscosity reduction effect on heavy oil.
[0096] Comparative Application Example 1
[0097] 80g of heavy oil was placed in a 500mL reactor. Water was added at a 1:1 oil-water ratio. Commercially available nano-Fe2O3 (80nm nano-Fe2O3, sourced from Suzhou Yanxin Materials Industrial Co., Ltd.) was added at a 1:0.005 weight ratio of heavy oil to catalyst. The reactor was heated to 240°C and stirred at 350 rpm for 24 hours. After the reaction, an oil sample was removed from the reactor and its post-reaction viscosity was measured using a viscometer at 50°C. During the measurement, the torque was maintained between 30% and 70%. The sample was then analyzed for changes in SRAR components.
[0098] The viscosity reduction rate (Δη) of heavy oil viscosity reduction catalyst is calculated by the following formula:
[0099]
[0100] Where η0 is the viscosity before reaction and η is the viscosity after reaction.
[0101] The present invention uses the commercial nano Fe2O3 in comparative example 1, and the SEM picture is as follows: Figure 8 The sample is a round particle with a stacked shape and a size distribution range of 50-200 nm.
[0102] The crude oil used in Comparative Example 1 of this application was Tuha heavy oil with a viscosity of 41,000 mPa·s. After reaction, the viscosity was reduced to 15,252 mPa·s, with a viscosity reduction rate of 62.8%. The SARA results are shown in Table 2. The saturates and aromatics contents increased slightly, the resin content decreased somewhat, and the asphaltene content decreased only slightly.
[0103] Table 2
[0104]
[0105]
[0106] Therefore, the viscosity reduction effect of the commercial nano-Fe2O3 catalyst in Comparative Example 1 was lower than that of Application Examples 1-6, indicating that the nano-metal oxide catalysts based on Fe2O3 prepared using wastewater are more effective than commercial nano-Fe2O3 in reducing the viscosity of heavy oil. Compared with Application Examples 1-4, Application Examples 5 and 6 showed significantly better viscosity reduction effects on heavy oil, with the saturates and aromatics contents increasing most significantly, while the colloid and asphaltene contents were greatly reduced. Thus, the nano-metal oxide catalysts obtained by modification with oleylamine and oleic acid in Application Examples 5 and 6 have good oil solubility, further improving the viscosity reduction rate.
[0107] In the description of this specification, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.
[0108] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.
Claims
1. A method for preparing a nano metal oxide catalyst for reducing the viscosity of heavy oil, characterized in that: The following steps are involved: A. dissolving an iron salt in waste water to obtain an iron salt solution, dissolving sodium hydroxide in the waste water to obtain a sodium hydroxide solution, and then dropwise adding the iron salt solution to the sodium hydroxide solution to mix to obtain a mixed solution; B. subjecting the mixed solution of step A to a hydrothermal reaction, centrifuging the reacted material, collecting the precipitate, washing and drying it to obtain a nano-metal oxide catalyst precursor; C. Adding the nano metal oxide catalyst precursor in step B to an oil-soluble modifier, centrifuging after the reaction, collecting the precipitate, and drying to obtain a nano metal oxide catalyst; the size of the nano metal oxide catalyst is 50 nm, the nano metal oxide catalyst has Fe2O3 as the main component, and also contains SiO2, CaO, MgO, and MnO components; the oil-soluble modifier includes oleic acid or oleylamine, and the mass ratio of the oil-soluble modifier to the nano metal oxide catalyst precursor is 1:1~3:
1.
2. The preparation method according to claim 1, characterized in that In step A, the iron salt includes at least one of ferric chloride hexahydrate, ferric nitrate nonahydrate and ferric sulfate.
3. The preparation method according to claim 1, characterized in that In step A, the mass ratio of the iron salt to the wastewater is (0.01-0.05):
1.
4. The preparation method according to claim 1, characterized in that In step A, the molar ratio of sodium hydroxide to iron salt is 3:
1.
5. The preparation method according to claim 1, characterized in that In step B, the temperature of the hydrothermal reaction is 140°C to 200°C.
6. The preparation method according to claim 1, characterized in that In step B, the hydrothermal reaction time is 6 to 16 hours.
7. Use of the nano metal oxide catalyst prepared by the preparation method according to any one of claims 1 to 6 in reducing the viscosity of heavy oil.