Nanofluid as well as preparation method and application thereof
By preparing high-density nanofluids, the limitations of energy density in traditional water media and the problem of nanopowder sedimentation were solved, enabling highly stable and efficient pumped storage applications and improving the system's energy storage density and adaptability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- 国网电力工程研究院有限公司
- Filing Date
- 2025-12-09
- Publication Date
- 2026-05-12
AI Technical Summary
Traditional water-based pumped storage systems have limited energy density, resulting in large power plant scale, difficult site selection, and long construction period. Furthermore, high-density nanoparticles are prone to sedimentation and agglomeration in the dispersion medium, leading to system instability.
By mixing nanoparticles, dispersants, and dispersion media in specific proportions, high-density nanofluids are prepared through the synergistic effect of electrostatic and spatial stabilization, preventing nanoparticle sedimentation and improving fluid density and stability.
The prepared nanofluids exhibit high anti-settling stability and dispersibility, with adjustable density, making them suitable for various operating conditions. This enhances the energy storage potential and mass transfer efficiency of pumped storage systems, adapts to different environments, and reduces application costs.
Abstract
Description
Technical Field
[0001] This invention relates to the field of pumped hydro storage energy storage medium preparation, specifically to a nanofluid, its preparation method, and its application. Background Technology
[0002] Pumped storage technology is currently the most widely used and mature large-scale energy storage technology in power systems, playing an irreplaceable role in ensuring grid stability and absorbing renewable energy. In pumped storage power stations, water serves as the traditional pumping medium, converting electrical energy into potential energy through circulation between upper and lower reservoirs. However, the energy density of water-based systems depends primarily on the water level difference, resulting in a limited energy density. This leads to the need for extremely large power station sizes to achieve the same storage capacity, presenting challenges such as difficult site selection, long construction periods, and high initial investment.
[0003] To overcome the energy density limitations of traditional water-based media, high-density nanofluids have significant application potential as novel pumped storage media. High-density nanofluids refer to solid-liquid two-phase fluids formed by stably dispersing nanoparticles in a base liquid. By selecting high-density nanoparticles, the overall fluid density can be significantly increased, thereby carrying greater kinetic and potential energy at the same flow rate and head, theoretically leading to a substantial increase in single-unit power and energy storage density. However, the development of this technology still faces a key bottleneck: high-density nanoparticles are prone to sedimentation and agglomeration in dispersion media such as water and seawater, leading to system instability and even pipe blockage; their stability is particularly prominent. Therefore, there is an urgent need to develop nanofluids with excellent anti-settling stability. Summary of the Invention
[0004] This invention provides a nanofluid, its preparation method, and its application. The nanofluid prepared by this invention exhibits excellent anti-settling stability.
[0005] In a first aspect, the present invention provides a nanofluid, comprising nanoparticles, a dispersant, and a dispersion medium; The mass ratio of the nanopowder, dispersant, and dispersion medium is (100-340):(0.34-2.6):(150-300). The dispersant includes one or more of sodium dodecyl sulfate, sodium citrate, and polyvinylpyrrolidone.
[0006] In one optional embodiment, the nanoparticles include one or more of ferric oxide, ferric oxide, titanium oxide, copper oxide, barium sulfate, and barium titanate. Optionally, the ferric oxide includes γ-ferric oxide.
[0007] Optionally, the titanium oxide includes titanium dioxide.
[0008] And / or, the dispersion medium includes one or more of fresh water, seawater, salt lake water, and calcium chloride solution; Preferably, when the dispersant is sodium dodecyl sulfate (SDS) or sodium citrate, the dispersion medium is one or more of fresh water, seawater, salt lake water, and calcium chloride solution; Preferably, when the dispersant is polyvinylpyrrolidone (PVP), the dispersion medium is one or more of fresh water, seawater, and salt lake water.
[0009] In one optional embodiment, the mass concentration of the calcium chloride solution is 29%-42%.
[0010] In one optional embodiment, the particle size of the nanoparticles ranges from 15 to 1000 nm.
[0011] In one alternative embodiment, the density of the nanofluid is ≥1.4 g / cm³. 3 ; Optionally, the density of the nanofluid is 1.4-2 g / cm³. 3 When the nanoparticles are selected, the nanoparticles include one or more of titanium oxide, barium sulfate, barium titanate, ferric oxide, ferric oxide, or copper oxide; the mass of the dispersant accounts for 0.01%-0.7% of the total mass of the nanofluid.
[0012] Optionally, the density of the nanofluid is 2-2.5 g / cm³. 3 When the nanoparticles are present, they include one or more of ferric oxide, iron oxide, or copper oxide; the mass of the dispersant accounts for 0.01%-0.7% of the total mass of the nanofluid.
[0013] Optionally, the density of the nanofluid is ≥2.5 g / cm³. 3 When the nanoparticles are present, they include one or two of ferric oxide and ferric oxide; the mass of the dispersant accounts for 0.01%-0.7% of the total mass of the nanofluid.
[0014] Secondly, the present invention provides a method for preparing the aforementioned nanofluid, comprising the following steps: The nanofluid is obtained by mixing and stirring the nanopowder, dispersant, and dispersion medium.
[0015] In one optional embodiment, the stirring is performed using mechanical stirring; Optionally, the mechanical stirring device is a mixer.
[0016] In one optional embodiment, the mechanical stirring speed is 100-150 r / min.
[0017] Thirdly, the present invention provides a pumped-storage energy storage medium for use as the working fluid in a pumped-storage power station, which employs the aforementioned nanofluid or a nanofluid prepared according to the aforementioned method.
[0018] The technical solution of this invention has the following advantages: 1. The nanofluid provided by the present invention comprises nanoparticles, a dispersant, and a dispersion medium; the mass ratio of the nanoparticles, the dispersant, and the dispersion medium is (100-340):(0.34-2.6):(150-300); the dispersant comprises one or more of sodium dodecyl sulfate, sodium citrate, and polyvinylpyrrolidone.
[0019] The dispersant in the nanofluid provided by this invention works by preventing and inhibiting the aggregation of nanoparticles into large particles and subsequent sedimentation. Through electrostatic stabilization, spatial stabilization, and synergistic electrostatic-spatial stabilization, it ensures and improves the anti-settling stability of the nanofluid. The nanofluid using the dispersant described in this invention exhibits high anti-settling stability and dispersibility, as shown by the time t required for the solid phase height to decrease to half the total fluid height. 1 / 2 The calculated settling rate is greater than or equal to three days. The uniform density of the nanofluid along the height direction is beneficial to the mass transfer and transport processes in nanofluid pumped storage.
[0020] Using the specific ratio of the present invention (mass ratio of nanopowder, dispersant, and dispersion medium of (100-340):(0.34-2.6):(150-300)), a concentration of 1.4-2 g / cm³ can be obtained. 3 2-2.5 g / cm 3 and 2.5 g / cm 3 The above-mentioned nanofluids with controllable density and high sedimentation stability provide technical support for applications under different working conditions.
[0021] This invention significantly improves fluid density and increases its energy storage potential by introducing high-density nanoparticles.
[0022] To address the issue of solid particles easily settling in the dispersion medium, the long-term stability of high-density nanofluids is effectively ensured by adding a specific proportion of dispersant.
[0023] 2. The nanopowder described in this application includes one or more of the following: ferric oxide, iron(II) oxide, titanium dioxide, copper oxide, barium sulfate, and barium titanate.
[0024] In its material selection, this application takes into account environmental friendliness, economy, and material stability. The material obtained by this invention has high stability and is not prone to corrosion problems in the use environment.
[0025] 3. The dispersion medium in the nanofluid provided by this invention includes one or more of fresh water, seawater, salt lake water, and calcium chloride solution. The mass concentration of the calcium chloride solution is 29%-42%.
[0026] Nanofluids formulated using high-concentration calcium chloride solution as a dispersion medium exhibit antifreeze properties, making them suitable for low-temperature environments. Calcium chloride solutions with a mass concentration range of 29%-42% have a density 28%-42% higher than fresh water, allowing the nanofluid's freezing point to be lowered to -15°C and below. The selection of various dispersion media demonstrates the nanofluid's environmental adaptability. This system can directly utilize natural water resources in different regions, reducing application costs. Furthermore, the antifreeze properties of the high-concentration calcium chloride solution enable the nanofluid to operate under conditions in different temperature zones, providing feasibility for the diversified deployment of pumped-storage systems.
[0027] 4. The preparation method of the nanofluid provided by the present invention includes the following steps: mixing and stirring nanoparticles, dispersant and dispersion medium to obtain the nanofluid. The stirring is performed by mechanical stirring, the device for mechanical stirring is a stirrer, and the rotation speed of the mechanical stirring is 100-150 r / min.
[0028] The mechanical stirring preparation process employed is simple, requires minimal equipment, and consumes little energy, making it easy to scale up production. This fluid, as a working medium for next-generation pumped-storage power plants, can be directly used to increase system power and energy storage density, which is of great significance for promoting the upgrading of energy storage technology. Detailed Implementation
[0029] The following embodiments are provided to better understand the present invention, but the following embodiments do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the scope of protection of the present invention.
[0030] Unless otherwise specified, all experimental steps or conditions in the examples were performed according to conventional experimental procedures and conditions in the art. Reagents or instruments whose manufacturers are not specified are all commercially available products.
[0031] Example 1 This embodiment provides a method for preparing nanofluids, including the following steps: Titanium dioxide nanoparticles with an average particle size of 15 nm, water, and sodium citrate dispersant were weighed and mixed in a specific ratio. The mixture was then mechanically stirred using a mixer to form a homogeneous and stable nanofluid. The process parameters are as follows: Mass ratio: The mass ratio of titanium dioxide nanoparticles, water, and sodium citrate is 100:150:1.0 to 100:300:1.0; Mechanical stirring speed: 100-150 r / min; Nanofluid density: 1.5 g / cm³ 3 It falls within the 1.4-2 g / cm³ range set in this invention. 3 Within the density range.
[0032] Example 2 This embodiment provides a method for preparing nanofluids, including the following steps: Barium sulfate nanoparticles with an average particle size of 50 nm, water, and sodium citrate dispersant were weighed and mixed in a specific ratio. The mixture was then mechanically stirred using a mixer to form a homogeneous and stable nanofluid. The process parameters are as follows: Mass ratio: The mass ratio of barium sulfate nanopowder, water, and sodium citrate is 160:150:1.6 to 160:300:1.6; Mechanical stirring speed: 100-150 r / min; Nanofluid density: 1.8 g / cm³ 3 The value falls within the range of 1.4-2.0 g / cm³ set in this invention. 3 Within the density range.
[0033] Example 3 This embodiment provides a method for preparing nanofluids, including the following steps: γ-ferric oxide nanoparticles with an average particle size of 20 nm, water, and polyvinylpyrrolidone (PVP) dispersant were weighed and mixed in a certain proportion. The mixture was then mechanically stirred using a mixer to form a homogeneous and stable nanofluid. The process parameters are as follows: Mass ratio: The mass ratio of γ-ferric oxide nanoparticles, water and polyvinylpyrrolidone (PVP) is 260:150:2.6 to 260:300:2.6; Mechanical stirring speed: 100-150 r / min; Nanofluid density: 2.3 g / cm³ 3 The value falls within the range of 2.0-2.5 g / cm³ set in this invention. 3 Within the density range.
[0034] Example 4 This embodiment provides a method for preparing nanofluids, including the following steps: Ferric oxide nanoparticles with an average particle size of 20 nm, water, and sodium dodecyl sulfate (SDS) dispersant were weighed and mixed in a specific ratio. The mixture was then mechanically stirred using a mixer to form a homogeneous and stable nanofluid. The process parameters are as follows: Mass ratio: The mass ratio of iron oxide nanoparticles, water and sodium dodecyl sulfate (SDS) is 340:150:0.34 to 340:300:2.6; Mechanical stirring speed: 100-150 r / min; Nanofluid density: 2.7 g / cm³ 3 The value falls within the ≥2.5 g / cm² specified in this invention. 3 Within the density range.
[0035] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.
Claims
1. A nanofluid, characterized in that, Includes nanoparticles, dispersants, and dispersion media; The mass ratio of the nanopowder, dispersant, and dispersion medium is (100-340):(0.34-2.6):(150-300). The dispersant includes one or more of sodium dodecyl sulfate, sodium citrate, and polyvinylpyrrolidone.
2. The nanofluid according to claim 1, characterized in that, The nanoparticles include one or more of the following: ferric oxide, iron(II) oxide, titanium dioxide, copper oxide, barium sulfate, and barium titanate.
3. The nanofluid according to claim 1, characterized in that, The dispersion medium includes one or more of fresh water, seawater, salt lake water, and calcium chloride solution.
4. The nanofluid according to claim 3, characterized in that, The mass concentration of the calcium chloride solution is 29%-42%.
5. The nanofluid according to claim 1 or 2, characterized in that, The particle size range of the nanoparticles is 15-1000 nm.
6. The nanofluid according to claim 1 or 2, characterized in that, The density of the nanofluid is ≥1.4 g / cm³. 3 .
7. A method for preparing the nanofluid according to any one of claims 1-6, characterized in that, Includes the following steps: The nanofluid is obtained by mixing and stirring the nanopowder, dispersant, and dispersion medium.
8. The method for preparing nanofluids according to claim 7, characterized in that, The stirring is performed using mechanical stirring. Optionally, the mechanical stirring device is a mixer.
9. The method for preparing nanofluids according to claim 8, characterized in that, The mechanical stirring speed is 100-150 r / min.
10. A pumped-storage energy storage medium for use as the working fluid in a pumped-storage power station, characterized in that, The nanofluid is prepared by any one of claims 1-6 or by any one of claims 7-9.