A MOF porous solution for adsorptive-hydrative coupled gas storage, its preparation method, and a method for adsorptive-hydrative coupled gas storage

Abstract

The present invention discloses a MOF porous solution for adsorptive - hydrate coupled gas storage, its preparation method, and a method for adsorptive - hydrate coupled gas storage. The MOF porous solution includes modified MOF powder and water, and the modified MOF powder is dispersed in the water to form a stable dispersion; the modified MOF powder includes MOF and a hydrophilic kinetic promoter, and the hydrophilic kinetic promoter is modified on the outer surface of the MOF, so that the inner cavity of the modified MOF powder is hydrophobic and the outer surface is hydrophilic; in the MOF porous solution, the concentration of MOF is 1 - 3 wt%, and the concentration of the hydrophilic kinetic promoter is 1000 - 6000 ppm. The present invention has the advantages of low cost, high dispersibility, being able to break through the storage capacity limit and improve the kinetic performance of hydrate formation, and can break the mass transfer barrier while achieving adsorptive and hydrate coupled gas storage, improving the gas storage speed and storage capacity.

Description

Technical Field

[0001] The present invention relates to the technical field of gas storage by hydrates, and particularly to a MOF porous solution for adsorptive-hydrative coupled gas storage, a preparation method thereof, and a method for adsorptive-hydrative coupled gas storage. Background Art

[0002] Existing natural gas hydrate (NGH) gas storage technologies are regarded as important storage methods for green transitional energy due to their safety and environmental protection characteristics. However, traditional hydrate methods have two major bottlenecks: one is the limited storage capacity, and the theoretical methane storage is only 150 - 170 V / V, which is difficult to meet industrial demands; the other is the serious mass transfer barrier. The hydrate formation rate in a static system is low, and additional energy input (such as stirring, bubbling) is required, increasing costs. Most current studies adopt an adsorptive-hydrative coupled gas storage technology mainly based on porous materials, among which porous materials are represented by metal-organic frameworks (MOFs). However, due to problems such as high MOF filling costs and significant adsorption heat effects, its large-scale application is restricted; in addition, in traditional methods, the poor dispersibility of MOFs in the liquid phase leads to low mass transfer efficiency, so the adsorptive-hydrative coupled gas storage technology still needs to be continuously improved.

[0003] It should be noted that the information disclosed in the above background art section is only for understanding the background of the present application, and thus may include information that does not constitute the prior art known to those of ordinary skill in the art. Summary of the Invention

[0004] The present invention provides a MOF porous solution for adsorptive-hydrative coupled gas storage, a preparation method thereof, and a method for adsorptive-hydrative coupled gas storage.

[0005] The present invention adopts the following technical solutions:

[0006] In the first aspect, there is provided a MOF porous solution for adsorptive-hydrative coupled gas storage, which comprises modified MOF powder and water, and the modified MOF powder is dispersed in the water to form a stable dispersion; the modified MOF powder comprises MOF and a hydrophilic kinetic promoter, and the hydrophilic kinetic promoter is modified on the outer surface of the MOF, so that the inner cavity of the modified MOF powder is hydrophobic and the outer surface is hydrophilic; in the MOF porous solution, the concentration of MOF is 1 - 3 wt%, and the concentration of the hydrophilic kinetic promoter is 1000 - 6000 ppm.

[0007] Preferably, the MOF is at least one of ZIF-8 and ZIF-67.

[0008] Preferably, the hydrophilic kinetic promoter is at least one of SDS, amino acids, and SDBS.

[0009] Preferably, the MOF is ZIF-8, and the hydrophilic kinetic promoter is SDS; in the MOF porous solution, the concentration of the MOF is 3 wt%, and the concentration of the hydrophilic kinetic promoter is 4500 ppm.

[0010] Preferably, the inner cavity of the modified MOF powder is a microporous structure with a pore diameter less than 2 nm; the specific surface area of the MOF is greater than 1000 m 2 / g; the absolute value of the Zeta potential of the MOF porous solution is ≥10 mV.

[0011] In a second aspect, a method for preparing the MOF porous solution according to the first aspect is provided, which includes the following steps:

[0012] (1) The hydrophilic kinetic promoter and the raw materials for preparing the MOF are stirred in a predetermined ratio, then centrifuged, dried, vacuum-activated, and ground to obtain the modified MOF powder;

[0013] (2) The modified MOF powder is added to water, ultrasonicated for a predetermined time, and then stirred at room temperature to form a stable dispersion to obtain the MOF porous solution;

[0014] Alternatively, it includes the following steps:

[0015] A. The hydrophilic kinetic promoter and the MOF are added to water in a predetermined ratio to prepare a solution;

[0016] B. The solution obtained in step A is ultrasonicated for a predetermined time and then stirred at room temperature to form a stable dispersion to obtain the MOF porous solution.

[0017] Preferably, the ultrasonic time in step (2) or step B is 30 - 60 min.

[0018] In a third aspect, a method for adsorbing-hydrating coupled gas storage based on the MOF porous solution according to the first aspect is provided, including the following steps:

[0019] (a) Inject the MOF porous solution into a high-pressure reactor and pre-cool it to a predetermined temperature;

[0020] (b) According to a predetermined gas-liquid volume ratio, pre-cool the gas to the same temperature as the MOF porous solution in the high-pressure reactor, then inject it into the high-pressure reactor to a predetermined pressure, and complete the adsorbing-hydrating coupled gas storage under static conditions (without stirring).

[0021] Preferably, the gas-liquid volume ratio in step (b) is in the range of 1:1 to 6:1; the predetermined pressure in step (b) is 6 - 10 MPa.

[0022] Preferably, the gas is methane, the MOF in the MOF porous solution is ZIF-8, the hydrophilic kinetic promoter is SDS, the concentration of MOF is 3 wt%, the concentration of the hydrophilic kinetic promoter is 4500 ppm, the predetermined temperature in step (a) is 275.15 K; the gas-liquid volume ratio in step (b) is 5:1.

[0023] The beneficial effects of the present invention include: the MOF porous solution of the present invention is a stable dispersion liquid. By modifying the surface of MOF with a hydrophilic kinetic promoter, a "hydrophilic outer shell - hydrophobic inner pore" bifunctional structure is constructed, solving the contradiction between the dispersibility and adsorption capacity of MOF, and solving the problems of weak methane hydrate formation kinetics, less solid methane content, and material waste in the prior art. Specifically, the modified MOF powder in the MOF porous solution has the characteristics of coexistence of a hydrophilic outer surface and a hydrophobic inner pore. Under static conditions, the MOF porous solution can enhance mass transfer by adsorbing gas, promoting the rapid nucleation of gas hydrate, and thus has excellent gas adsorption performance. Therefore, the MOF porous solution of the present invention not only accelerates the kinetic formation of gas hydrate, improves the overall adsorption and hydrate formation kinetics, increases the theoretical storage of gas hydrate, but also realizes static high-efficiency storage, can spontaneously adsorb gas without additional mechanical energy consumption, and generate hydrate to achieve high-density solid storage of gas, and reduces the amount of material used, improves the economic efficiency of the application of this method, limits the diffusion of chemicals, and reduces the environmental impact of promoter use. Generally speaking, the present invention has the advantages of low cost, high dispersibility, being able to break through the storage capacity limit and improve the hydrate formation kinetics performance, and can achieve the coupling of adsorption and hydrate for gas storage while breaking through the mass transfer barrier, improving the gas storage speed and storage capacity. Description of the Drawings

[0024] Figures 1(a), 1(b) and 1(c) are respectively the SEM image, TEM image, and pore size distribution diagram of the modified MOF powder in Example 1 of the present invention;

[0025] Figures 1(d) and 1(e) are respectively the N2 adsorption - desorption curves of the MOF before modification and the modified MOF in Example 1 of the present invention;

[0026] Figure 2 is the comparison result between the MOF porous solution and the MOF slurry in Example 1 of the present invention;

[0027] Figure 3 is the density characterization result of MOF porous solutions with different concentrations;

[0028] Figure 4 In an experiment of the present invention for adsorptive-hydrative coupled storage of methane using a MOF porous solution with a MOF concentration of 1 wt% and an SDS concentration of 1000 ppm, it is a graph of the cyclic gas storage performance of the MOF porous solution;

[0029] Figure 5 It is a comparison graph of the gas storage amounts of the SDS solution, the MOF slurry, and the MOF porous solution in the examples;

[0030] Figure 6 It is the Zeta potential detection results of MOF porous solutions with different concentrations before and after hydrate formation. Detailed Embodiments

[0031] The following makes a detailed description of the embodiments of the present invention. It should be emphasized that the following description is merely exemplary and not intended to limit the scope of the present invention and its applications. Without conflict, the embodiments in this application and the features in the embodiments can be combined with each other.

[0032] The detailed embodiments of the present invention provide a MOF porous solution for adsorptive-hydrative coupled storage of gases, which includes modified MOF powder and water. The modified MOF powder is dispersed in the water to form a stable dispersion; the modified MOF powder includes MOF and a hydrophilic kinetic promoter, and the hydrophilic kinetic promoter is modified on the outer surface of the MOF, so that the inner cavity of the modified MOF powder is hydrophobic and the outer surface is hydrophilic; in the MOF porous solution, the concentration of MOF is 1-3 wt%, and the concentration of the hydrophilic kinetic promoter is 1000-6000 ppm.

[0033] In the above technical solution, MOF has a large internal adsorption space and adsorption sites. Its inner cavity is hydrophobic to avoid the intrusion of water molecules, and the outer surface of MOF is modified with a hydrophilic kinetic promoter to have hydrophilicity and good compatibility with water, so that the modified MOF powder can be evenly dispersed in water. Through the above concentrations of MOF and the hydrophilic kinetic promoter, the dispersion stability of MOF particles in water can be ensured, and a stable dispersion (the density of this dispersion is greater than that of water) can be formed, thereby ensuring that the MOF porous solution has a large gas adsorption capacity in the water phase to increase the gas storage amount through adsorption, and also acting as a kinetic promoter for gas hydrates to promote the formation of gas hydrates, and improving the gas storage speed and storage amount when used for adsorptive-hydrative coupled storage of gases.

[0034] In the above technical solution, the hydrophilic outer surface and hydrophobic inner pores of the modified MOF particles coexist. Under static conditions, the MOF porous solution can enhance mass transfer by adsorbing gas, promoting the rapid nucleation of gas hydrates, and thus has excellent gas adsorption performance.

[0035] In some embodiments, the MOF is at least one of ZIF-8 (coordination metal is zinc, ligand is 2-methylimidazole) and ZIF-67 (coordination metal is cobalt, ligand is 2-methylimidazole).

[0036] In some embodiments, the hydrophilic kinetic promoter is at least one of SDS (sodium dodecyl sulfate), amino acids, and SDBS (sodium dodecylbenzenesulfonate).

[0037] In some embodiments, the MOF is ZIF-8 and the hydrophilic kinetic promoter is SDS; in the MOF porous solution, the concentration of MOF is 3 wt%, and the concentration of the hydrophilic kinetic promoter is 4500 ppm.

[0038] In some embodiments, the inner cavity of the modified MOF powder is a microporous structure with a pore diameter less than 2 nm; the specific surface area of the MOF is greater than 1000 m 2 / g. After the MOF is modified with the hydrophilic kinetic promoter, the specific surface area will decrease.

[0039] In some embodiments, the stable dispersion satisfies: the absolute value of the Zeta potential of the MOF porous solution ≥ 10 mV. More preferably, it also satisfies that the MOF porous solution does not show visible sedimentation or suspension after standing for 24 h.

[0040] The specific embodiment of the present invention also provides a method for preparing the above-mentioned MOF porous solution, which includes the following steps:

[0041] (1) The hydrophilic kinetic promoter and the raw materials for preparing the MOF are stirred in a predetermined ratio, then centrifuged, dried, vacuum-activated, and ground to obtain the modified MOF powder. Taking ZIF-8 as an example of MOF, the hydrophilic kinetic promoter, 2-methylimidazole, and zinc nitrate hexahydrate are stirred in a certain ratio, then centrifuged, dried, vacuum-activated (such as activated at 120 °C in a vacuum oven for at least 12 h), and ground to obtain the modified MOF powder. That is, on the basis of the well-known MOF preparation method in the art, a hydrophilic kinetic promoter is added to prepare the modified MOF powder. In this process (1), the hydrophilic kinetic promoter is modified on the outer surface of the MOF.

[0042] (2) Add the modified MOF powder into water, ultrasonicate for a predetermined time, and then stir at room temperature to form a stable dispersion to obtain the MOF porous solution; during this process (2), the modified MOF powder is uniformly dispersed in water.

[0043] Alternatively, it includes the following steps:

[0044] A. Add the hydrophilic kinetic promoter and the MOF into water in a predetermined ratio to prepare a solution;

[0045] B. Ultrasonicate the solution obtained in step A for a predetermined time, and then stir at room temperature to form a stable dispersion to obtain the MOF porous solution. During this process B, the hydrophilic kinetic promoter is modified on the outer surface of the MOF and then uniformly dispersed in water.

[0046] In some embodiments, the sonication time in step (2) or step B is 30 - 60 min. At this sonication time, it is ensured that the MOF porous solution is a stable dispersion rather than in states such as slurry, suspension, suspension slurry, etc.

[0047] In some embodiments, after sonication, stir in a water bath at room temperature (295 - 299K) until the Zeta potential of the detected solution meets the predetermined requirement (preferably the absolute value of the Zeta potential ≥ 10 mV), for example, stir for 30 min.

[0048] The specific embodiments of the present invention also provide a method for adsorptive - hydration coupled gas storage based on the above - mentioned MOF porous solution, including the following steps:

[0049] (a) Inject the above - mentioned MOF porous solution into a high - pressure reactor and pre - cool it to a predetermined temperature;

[0050] (b) According to the predetermined gas - liquid volume ratio, pre - cool the gas to the same temperature as the MOF porous solution in the high - pressure reactor, and then inject it into the high - pressure reactor to a predetermined pressure. Under static conditions, complete the adsorptive - hydration coupled gas storage. Among them, a constant - pressure storage capacity test experiment can be carried out. Inject methane to a predetermined pressure at one time, and then store it for a predetermined time (such as 24 h) under static conditions; a variable - pressure storage capacity test experiment can also be carried out. The injection of methane is gradual. Inject 0.5 MPa to 1 MPa of methane into the storage tank every not less than 30 min until the pressure reaches the predetermined pressure and then end, and then store it for a predetermined time (such as 24 h) under static conditions.

[0051] In some embodiments, the gas - liquid volume ratio in step (b) is in the range of 1:1 - 6:1; the predetermined pressure in step (b) is 6 - 10 MPa.

[0052] In some embodiments, the gas is methane, the MOF in the MOF porous solution is ZIF-8, the hydrophilic kinetic promoter is SDS, the concentration of the MOF is 3 wt%, the concentration of the hydrophilic kinetic promoter is 4500 ppm, the predetermined temperature in step (a) is 275.15 K; the gas-liquid volume ratio in step (b) is 5:1.

[0053] The specific embodiments of the present invention are further described below.

[0054] Example 1

[0055] The preparation method of the MOF porous solution includes the following steps:

[0056] (1) In the MOF porous solution, with the concentration of the MOF being 3 wt% and the concentration of SDS being 4500 ppm, SDS, zinc nitrate hexahydrate, and 2-methylimidazole are stirred, centrifuged, dried, vacuum-activated, and ground to obtain modified MOF powder, denoted as ZIF-8@SDS. As shown in Figures 1(a), 1(b), and 1(c), they are respectively the SEM image, TEM image, and pore size distribution diagram of the modified MOF powder. As shown in Figures 1(d) and 1(e), they are respectively the N2 adsorption-desorption curves of the MOF before modification and the MOF after modification. It can be seen therefrom that the measured specific surface area of the MOF (ZIF-8) before modification is 1483 m 2 / g, and the specific surface area of the MOF (ZIF-8@SDS) after modification is 245 m 2 / g.

[0057] (2) The modified MOF powder is added to water, ultrasonicated for 30 min, and then stirred at room temperature for 30 min to form a stable dispersion to obtain the MOF porous solution. The Zeta potential of this MOF porous solution (measured using a Zetasizer Nano ZS90 instrument) is -40 mV, and the liquid density is 1.004 g / ml.

[0058] To illustrate that the MOF porous solution of the present invention is a stable dispersion, for comparison, the present invention also prepared a MOF slurry (formed by directly dispersing ZIF-8 in water, with the concentration of ZIF-8 being 3 wt%). As Figure 2 shown, it is the comparison result of the MOF porous solution and the MOF slurry of the present invention. It can be seen therefrom that in the MOF porous solution of the present invention, the particles are evenly dispersed, with good dispersibility, forming a stable dispersion, while in the MOF slurry, it can be clearly seen that the particles in the solution are unevenly dispersed, with obvious particle suspension in the upper layer and obvious particle sedimentation in the lower layer of the solution.

[0059] In some other embodiments, different from Embodiment 1, the concentrations of MOF and SDS in the MOF porous solution are different, and the obtained modified MOF powders are respectively denoted as ZIF-8@SDSw1 (MOF is 0.5 wt%, SDS is 1000 ppm), ZIF-8@SDSw2 (MOF is 1 wt%, SDS is 1000 ppm), ZIF-8@SDSw3 (MOF is 1.5 wt%, SDS is 1000 ppm). As Figure 3 shown, it is the density characterization result of the MOF porous solution obtained with these modified MOF powders, indicating that the density of the MOF porous solution of the present invention is greater than that of water.

[0060] Embodiment 2

[0061] This embodiment provides a method for adsorptive-hydrative coupled storage of methane based on the MOF porous solution of Embodiment 1, including the following steps:

[0062] (a) Inject the MOF porous solution of Embodiment 1 into a high-pressure reactor and pre-cool it to 275.15 K; wherein, the high-pressure reactor adopts a double-layer stainless steel storage tank, with an appropriate amount of the MOF porous solution of Embodiment 1 injected into the inner layer, and the outer layer is a vacuum insulation layer, with a design pressure of 10 MPa. A temperature control module, a temperature sensor, a pressure sensor, and a visualization monitoring device are configured in the double-layer stainless steel storage tank, and the temperature in the high-pressure reactor is maintained at 275.15 K through the temperature control module.

[0063] (b) According to the gas-liquid volume ratio of 5:1, after injecting methane gas into the buffer tank and pre-cooling it to 275.15 K, inject the pre-cooled methane from the buffer tank into the high-pressure reactor until the pressure reaches 7.2 MPa. In this example, a variable-pressure storage test is carried out, and the injection of methane is gradual. Methane of 0.5 MPa to 1 MPa is injected into the storage tank every no less than 30 min until the pressure reaches 7.5 MPa and then stored statically for 24 hours to complete the adsorptive-hydrative coupled storage of methane; in this example, the purity of the methane gas is greater than 99%.

[0064] When conducting the above storage experiment, real-time monitoring can be carried out through the temperature sensor, the pressure sensor, and the visualization device to judge the pressure and temperature changes before the formation of methane hydrate, monitor the formation position and spatial growth mode of methane hydrate, etc., and calculate the final adsorptive-hydrative coupled storage capacity of methane in the MOF porous solution (in this example, the storage capacity of methane is 206.3 V / V), providing directional guidance for subsequent gas injection.

[0065] After the storage is completed, if particle sedimentation or suspension is visually observable in the remaining MOF porous solution in the high-pressure reactor, it indicates a decrease in dispersibility. Alternatively, the dispersibility can be measured through Zeta potential detection (which can be measured using a Zetasizer Nano ZS90 instrument). If the dispersibility decreases (for example, the absolute value of the Zeta potential is less than 10 mV), the solution is ultrasonically treated for a predetermined time and then stirred and dispersed at room temperature before conducting the methane storage experiment. If the dispersibility is good (for example, the absolute value of the Zeta potential is not less than 10 mV), the methane storage experiment can be directly carried out. Thus, the MOF porous solution can be recycled.

[0066] In an experiment on the coupled adsorption-hydration storage of methane using a MOF porous solution with a MOF concentration of 1 wt% and an SDS concentration of 1000 ppm, the MOF porous solution was recycled three times for gas storage, as Figure 4 shown, which is the cyclic gas storage performance graph of the MOF porous solution. The capacity retention rate of the MOF porous solution after 3 cycles is > 90%.

[0067] For comparison, the present invention also carried out methane storage experiments on SDS solution and MOF slurry (i.e., the slurry shown in the left container in Figure 2 in the same steps (a)-(b) as in Example 2). Their methane storage amounts were compared with those of the MOF porous solution in Example 1, as Figure 5 shown. It can be seen from this that the methane storage amount of the MOF porous solution of the present invention is significantly greater than that of the two comparative solutions.

[0068] As Figure 6 shown, this is the result of Zeta potential detection (measured using a Zetasizer Nano ZS90 instrument) of different concentrations of MOF porous solutions (represented in the figure as: SDS concentration + SDS@MOF concentration + MOF form, such as 1000 ppm SDS@1.0 wt% MOF) before and after hydrate formation. This figure shows that the dispersion stability of the particles in the MOF porous solution of the present invention does not degrade after recycling.

[0069] When used for methane storage and transportation, during the above storage process, the pressure change can be monitored. During transportation, the pressure is maintained at about 7.0 MPa through a pressure regulating valve. After reaching the destination, methane is gradually released through a pressure reducing valve, and the methane adsorbed in the inner pores of the MOF is simultaneously desorbed to achieve continuous gas supply.

[0070] Traditional natural gas storage and transportation rely on compressed natural gas (CNG, pressure 20 MPa) or liquefied natural gas (LNG, -162 °C low temperature), but there are problems such as high energy consumption and great safety hazards. In this embodiment, the MOF porous solution adsorption-hydration coupled storage of methane achieves a high methane storage capacity (in this example, the methane storage capacity is 206.3 V / V, exceeding the traditional hydrate theoretical limit (about 170 V / V) by 21.5%, breaking through the theoretical upper limit of gas storage). There is no need for low temperature, the risk of tank leakage is reduced by 90%, the material usage cost is reduced, the transportation cost is reduced by 40% compared with LNG, and the equipment investment is reduced by 30%. Therefore, this embodiment has the following advantages:

[0071] (1) Through the adsorption-hydration synergistic effect of the MOF porous solution, the methane storage capacity reaches 206.3 V / V (the traditional hydrate upper limit is 170 V / V), an increase of 21.5%, breaking through the theoretical upper limit of gas storage.

[0072] (2) It has ultra-fast gas storage kinetic characteristics and zero induction time: there is almost no delay in hydrate nucleation under static conditions, and the main storage is completed within 5 minutes.

[0073] (3) Achieve a high conversion rate of hydrate, the storage rate reaches 0.231 V / V·min (the traditional SDS solution is only 0.103 V / V·min), and it has low energy consumption and high stability, without mechanical stirring: through the spontaneous driving of mass transfer by MOF dispersion and adsorption, the energy consumption is reduced by more than 50%.

[0074] (4) Excellent cycle performance: the capacity retention rate > 90% after 3 cycles, and the Zeta potential test shows that the particle dispersion stability has not deteriorated.

[0075] The present invention realizes high-density methane storage under mild conditions through the MOF porous solution. The dual-functional design of the hydrophilic outer shell and hydrophobic inner pores of the MOF porous solution enables the MOF to be uniformly dispersed in the liquid phase, avoiding the aggregation problem caused by the hydrophobicity of traditional MOF. In a static system, the inner pores of the MOF adsorb methane to form a local high-concentration gas source, breaking through the mass transfer limitation at the gas-liquid interface, and increasing the methane dissolution rate by more than 50%. The methane adsorbed in the inner pores of the MOF is gradually released through the concentration gradient, providing a stable gas source for the continuous growth of hydrates. It is a new solution for natural gas storage and transportation; the preparation process of the MOF porous solution of the present invention is simple, without complex equipment, achieving cost savings, and is expected to achieve industrial application.

[0076] The above content is a further detailed description of the present invention in combination with specific / preferred embodiments, and it cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention pertains, without departing from the concept of the present invention, they can also make several substitutions or modifications to these described embodiments, and these substitution or modification methods should all be regarded as belonging to the protection scope of the present invention. In the description of this specification, the description with reference to terms such as "an embodiment", "some embodiments", "preferred embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. Without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions, and alterations can be made herein without departing from the scope of protection of the patent application.

Claims

1. A MOF porous solution for adsorption-hydration coupled gas storage, characterized in that: The invention comprises modified MOF powder and water, wherein the modified MOF powder is dispersed in the water to form a dispersion liquid in a stable state with uniform particle dispersion and good dispersibility; the modified MOF powder comprises MOF and a hydrophilic kinetic promoter, wherein the hydrophilic kinetic promoter is modified on the outer surface of the MOF to construct a "hydrophilic outer shell-hydrophobic inner pore" dual-functional structure, so that the inner cavity of the modified MOF powder is hydrophobic and the outer surface is hydrophilic; in the MOF porous solution, the concentration of MOF is 1-3wt%, and the concentration of the hydrophilic kinetic promoter is 1000-6000ppm; the MOF is at least one of ZIF-8 and ZIF-67; the hydrophilic kinetic promoter is at least one of SDS, amino acid and SDBS.

2. The MOF porous solution according to claim 1, characterized in that The MOF is ZIF-8, and the hydrophilic kinetic promoter is SDS; in the MOF porous solution, the concentration of MOF is 3wt%, and the concentration of the hydrophilic kinetic promoter is 4500ppm.

3. The MOF porous solution according to claim 1, characterized in that The inner cavity of the modified MOF powder is a microporous structure with a pore size of less than 2nm; the specific surface area of ​​the MOF is greater than 1000m 2 / g; the absolute value of the Zeta potential of the MOF porous solution is ≥10mV.

4. A method for preparing the MOF porous solution according to any one of claims 1 to 3, characterized in that: The steps include: (1) mixing the hydrophilic kinetic promoter and the raw material for preparing the MOF in a predetermined ratio, centrifuging, drying, vacuum activating, and grinding to obtain the modified MOF powder; (2) adding the modified MOF powder into water, subjecting it to ultrasonic treatment for a predetermined time, and then stirring it at room temperature to form a stable dispersion to obtain the MOF porous solution.

5. The preparation method according to claim 4, characterized in that: The ultrasonic time in step (2) is 30-60 min.

6. A method for storing gas by adsorption-hydration coupling of the MOF porous solution according to any one of claims 1 to 3, characterized in that: The steps include: (a) injecting the MOF porous solution according to any one of claims 1 to 3 into a high-pressure reactor and precooling it to a predetermined temperature; (b) According to a predetermined gas-liquid volume ratio, the gas is precooled to the same temperature as the MOF porous solution in the high-pressure reactor, and then injected into the high-pressure reactor to a predetermined pressure to complete the adsorption-hydration coupled storage of the gas under static conditions.

7. The method according to claim 6, characterized in that The gas-liquid volume ratio in step (b) is in the range of 1:1 to 6:1; the predetermined pressure in step (b) is 6-10 MPa.

8. The method according to claim 6, characterized in that The gas is methane, and the MOF porous solution is the MOF porous solution described in claim 2; the predetermined temperature in step (a) is 275.15 K; and the gas-liquid volume ratio in step (b) is 5:1.

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