Hydrogen adsorption and storage composite material for high-humidity-heat environment of coal mine as well as preparation method and application of hydrogen adsorption and storage composite material

Abstract

The invention provides a hydrogen adsorption and storage composite material for a high-hygrothermal environment of a coal mine as well as a preparation method and application of the hydrogen adsorption and storage composite material, and relates to a high-efficiency hydrogen adsorption and storage composite material. The method comprises the following steps: activating activated carbon to obtain pretreated activated carbon; the method comprises the following steps: soaking zeolite in a NaCl solution, and drying to obtain pretreated zeolite; mixing ZIF-8, the pretreated activated carbon and zeolite, and adding the mixture into a ball mill for ball milling to obtain composite powder; mixing and stirring the obtained composite powder and a binder, curing into a sphere by adopting a spray drying method, and drying and heating to form a porous structure, thereby obtaining the hydrogen adsorption and storage composite material for the high-humidity-heat environment of the coal mine. According to the MOFs composite material disclosed by the invention, efficient separation and storage of hydrogen in a complex gas source are realized by utilizing a hierarchical pore structure and moisture-resistant stability of the material, relatively high hydrogen adsorption capacity and relatively high adsorption rate can be kept in a high-humidity-heat environment, and the MOFs composite material is suitable for high-risk environments such as a coal mine and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of high-efficiency hydrogen adsorption storage composite material, specifically to a kind of hydrogen adsorption storage composite material for coal mine high-humid heat environment and its preparation method and application. BACKGROUND

[0002] In the industry of coal mine, petroleum, natural gas, gas leakage and accumulation, especially the leakage of hydrogen, has caused serious threat to the safety of mine and working environment. In the disaster events such as spontaneous combustion of coal mine, gas leakage, the existence of flammable and explosive gas such as hydrogen increases the security risk. Therefore, it has important application value to develop a kind of material with good hydrogen adsorption capacity and long-term stable work in high-humid heat, low-oxygen environment.

[0003] At present, there are many studies on hydrogen adsorption and storage technology, but most of the materials are sensitive to moisture, poor in stability or the adsorption performance rapidly decays in extreme environment. Therefore, a new type of composite material that can effectively adsorb hydrogen for a long time in complex environment and ensure safety is urgently needed. SUMMARY

[0004] The present application aims to provide a kind of hydrogen adsorption storage composite material for coal mine high-humid heat environment and its preparation method and application, which can work stably in high-humid heat environment such as coal mine, has high hydrogen adsorption capacity, good environmental adaptability, especially maintains excellent adsorption performance under high temperature, humidity and low oxygen conditions.

[0005] The present application first provides a kind of preparation method of hydrogen adsorption storage composite material for coal mine high-humid heat environment, comprising: Step one: activate activated carbon to obtain pretreated activated carbon; soak zeolite in NaCl solution, then dry to obtain pretreated zeolite; Step two: mix ZIF-8, pretreated activated carbon and zeolite, add them into a ball mill for ball milling to obtain a composite powder; Step three: mix and stir the composite powder obtained in step two with a binder, solidify into spherical shape by spray drying method, dry, increase temperature to form a porous structure, to obtain a hydrogen adsorption storage composite material for coal mine high-humid heat environment.

[0006] Preferably, the activation conditions in step one are: activation treatment is carried out in N2 atmosphere, the activation temperature is 500-1000℃, and the activation time is 1-3h.

[0007] Preferably, the soaking time in step one is 6-24h, the temperature of NaCl solution is controlled above 60℃, stirring is continued during soaking, the drying temperature is 100-150℃, and the drying time is 2-6h.

[0008] Preferably, in step two, the mass ratio of ZIF-8, pretreated activated carbon, and zeolite is 2:2:6.

[0009] Preferably, the ball milling conditions in step two are: ball-to-material ratio (8-12):1, rotation speed of 200r / min-400r / min, and ball milling for more than 4 hours.

[0010] Preferably, the adhesive in step three is a mixture of PVDF and N-methylpyrrolidone.

[0011] Preferably, the mass ratio of the composite powder to the binder in step three is (92-95):(5-8).

[0012] Preferably, the spray drying conditions described in step three are: atomization pressure set ≥0.5MPa.

[0013] The present invention also provides a hydrogen adsorption and storage composite material for high humidity and heat environment in coal mines obtained by the above preparation method, wherein the composite material has a multi-level porous structure with both micropores and mesopores.

[0014] The present invention also provides the application of the above-mentioned composite material in hydrogen adsorption and storage in high-humidity and hot environments such as coal mines, natural gas extraction, and oil refining.

[0015] Beneficial effects of the present invention 1. Highly efficient hydrogen adsorption performance: The MOFs composite material of this invention utilizes the material's hierarchical porous structure and moisture resistance to achieve highly efficient separation and storage of hydrogen from complex gas sources. It can maintain a high hydrogen adsorption capacity and a relatively fast adsorption rate in high humidity (humidity ≤80%) and high temperature (temperature ≤320K) environments, making it suitable for high-risk environments such as coal mines.

[0016] 2. Excellent Environmental Adaptability: This invention utilizes ZIF-8, AC, and zeolite. ZIF-8 provides highly selective adsorption sites, while AC enhances mechanical strength and impurity adsorption. The functional groups on the AC surface preferentially adsorb impurities such as H2S, protecting the ZIF-8 structure from corrosion, making it suitable for downhole gas sources with high impurities. Zeolite, through pore size sieving (0.5 nm), blocks large molecules such as CH4, forming a synergistic "adsorption-sieving-stabilization" mechanism. The composite material of this invention enhances the stability of the hydrogen storage material, enabling it to operate stably for extended periods under high humidity and high temperature environments. Experimental results show that the composite material of this invention has an H2 adsorption capacity ≥0.32 mmol / g and a CO2 / H2 selectivity ≥2.5 under conditions of 320 K and 100 bar, making it suitable for high-humidity and high-temperature gas sources containing impurities such as CO2 and CH4.

[0017] 3. Improved safety: The high-efficiency hydrogen adsorption function of this composite material effectively prevents hydrogen leakage and accumulation, reducing the risk of explosion in environments such as mines.

[0018] 4. Lower material costs, saving approximately 80% compared to pure Zif-8 materials, making it suitable for large-scale industrial applications. Attached Figure Description

[0019] Figure 1 The pore size distribution curves for the composite materials of Example 1 and Comparative Example 1 of this invention are calculated based on the nitrogen adsorption-desorption curve at 77K.

[0020] Figure 2 The hydrogen adsorption isotherms of the composite materials of Example 1 and Comparative Example 1 of this invention are shown.

[0021] Figure 3 The hydrogen desorption isotherms of the composite materials of Example 1 and Comparative Example 1 of this invention are shown. Detailed Implementation

[0022] This invention first provides a method for preparing a hydrogen adsorption and storage composite material for use in high-humidity and high-temperature environments in coal mines, comprising: Step 1: Activate the activated carbon (AC). Preferably, the activation is carried out in an N2 atmosphere at 500-1000℃ for 1-3 hours to remove surface impurities and improve the micropore opening rate, thereby obtaining pretreated activated carbon. Soak the zeolite in a NaCl solution with stirring for 6-24 hours. The NaCl solution concentration is preferably 1M, and the NaCl solution temperature is controlled above 60℃. Stirring is carried out continuously during soaking. Afterward, wash with water until neutral, and preferably dry at 100-150℃ for 2-6 hours to enhance surface polarity, thereby obtaining pretreated zeolite. The zeolite is preferably 5A zeolite.

[0023] Step 2: Mix ZIF-8, pretreated activated carbon and zeolite, and add them to a ball mill for ball milling. The preferred ball milling conditions are: ball-to-material ratio (8-12):1, more preferably 10:1, and ball milling at 200-400 r / min for more than 4 hours to obtain uniform micron-sized composite powder; the preferred mass ratio of ZIF-8, pretreated activated carbon and zeolite is 2:2:6.

[0024] Step 3: Mix the composite powder obtained in Step 2 with the binder and solidify it into spherical particles using a spray drying method. The atomization pressure is preferably set to not less than 0.5 MPa, and more preferably 1.0 MPa. The slurry is sprayed through an atomizing nozzle and rapidly solidified into spherical particles in a drying tower. The spherical particles are preferably dried in a 60℃ oven for 12 hours to remove moisture. The particle size of the spherical particles is 0.1 mm (±0.05 mm). Heating is then used to form a porous structure. The heating is preferably done in an N2 atmosphere, preferably at a rate of 5℃ / min to 100℃, to obtain a hydrogen adsorption and storage composite material for use in high-humidity and high-temperature environments in coal mines. The binder is preferably a mixture of PVDF and N-methylpyrrolidone (NMP), with a preferred mass ratio of PVDF to NMP of 1:9. The mixing time for PVDF and NMP is preferably 2 hours. The mass ratio of the composite powder to the binder is preferably (92-95):(5-8), more preferably 95:5.

[0025] According to the present invention, a hydrophobic layer is formed on the surface of ZIF-8 by a PVDF binder, which effectively suppresses the competition of water molecules for adsorption sites under high humidity environment. By adjusting the proportion of PVDF binder (5%-8%), the moisture resistance of the material is improved. Under an 80% humidity environment, the H2 adsorption amount decreases by ≤20%.

[0026] According to the present invention, the preparation of ZIF-8 in step two includes: 1) Dissolve 2-methylimidazole in methanol and stir until clear to obtain solution A; the volume ratio of 2-methylimidazole to methanol is preferably 1.2:10, and the stirring time is preferably 30 min; 2) Dissolve zinc nitrate in methanol and stir to obtain solution B; the volume ratio of zinc nitrate to methanol is preferably 1:10, and the stirring time is preferably 15 min; Solution B is slowly poured into solution A and stirred for 1 hour. The mixture is then allowed to stand at room temperature for 24 hours. The precipitate is collected by centrifugation, washed three times with methanol, and dried under vacuum at 60°C for 12 hours to obtain ZIF-8 powder.

[0027] The present invention also provides a hydrogen adsorption and storage composite material for high humidity and heat environment in coal mines obtained by the above preparation method, wherein the composite material has a multi-level porous structure with both micropores and mesopores.

[0028] This invention also provides the application of the above-mentioned composite material in hydrogen adsorption and storage in high-humidity and high-temperature environments such as coal mines, natural gas extraction, and oil refining. By combining online sensor technology to monitor hydrogen concentration in real time, and initiating the adsorption process through an automated adsorption system when the concentration exceeds a safety threshold, the risk of gas leakage and explosion is effectively reduced.

[0029] The present invention will be further described in detail below with reference to specific embodiments. All raw materials involved in the embodiments are commercially available. Example 1

[0030] Step 1: ZIF-8 Synthesis and Pretreatment of Activated Carbon and Zeolite 1. Dissolve 1.2 parts by volume of 2-methylimidazole in 10 parts by volume of methanol and stir for 30 min until clear to obtain solution A; dissolve 1 part by volume of zinc nitrate in 10 parts by volume of methanol and stir for 15 min to obtain solution B; slowly pour B into A, place under a magnetic rotor and stir vigorously for 1 h, let stand at room temperature for 24 h; collect the precipitate by centrifugation, wash 3 times with methanol, and dry under vacuum at 60℃ for 12 h to obtain ZIF-8 powder.

[0031] 2. Activated carbon is activated at 500℃ for 2 hours in a N2 atmosphere to remove surface impurities and improve the micropore opening rate.

[0032] 3.5A zeolite was soaked in 1M NaCl solution for 24 hours, washed with water until neutral, and dried at 150℃ for 4 hours to enhance surface polarity.

[0033] Step 2: Preparation of hydrogen storage materials 1. Mix ZIF-8, AC and zeolite in a mass ratio of 2:2:6, add to a planetary ball mill (ball-to-material ratio 10:1), and ball mill at 300 r / min for 4 h to form a uniform micron-sized composite powder.

[0034] 2. PVDF and N-methylpyrrolidone (NMP) are mixed at a mass ratio of 1:9 and stirred for 2 hours to form a colloidal binder.

[0035] 3. Mix ZIF-8, AC and zeolite composite powder with binder at a mass ratio of 95:5. Use spray drying method, set the atomization pressure to 1.0MPa, spray the slurry through the atomizing nozzle, and quickly solidify it into spherical shape in the drying tower. Dry the spherical particles in an oven at 60℃ for 12h to remove moisture. Then, heat the spherical particles to 100℃ in a N2 atmosphere at a rate of 5℃ / min to form a porous structure.

[0036] Performance testing and optimization: 1.77K Experiment: The adsorption-desorption equilibrium data of nitrogen on the hydrogen storage material at 77K were tested using a fully automated microporous adsorption analyzer. Before the test, to remove impurity gases from the hydrogen storage material channels, the hydrogen storage material was vacuum degassed at 100℃ for 12 hours. Based on the N2 adsorption data of the hydrogen storage material at 77K, the specific surface area of ​​the hydrogen storage material was determined using the BET equation, and the pore size and pore size distribution of the hydrogen storage material were calculated using the HK equation.

[0037] 2. Hydrogen absorption and desorption kinetics test: Saturated moist hydrogen and dry hydrogen were introduced into the adsorption analyzer at a volume ratio of 4:1 to conduct hydrogen absorption and desorption kinetics tests on the hydrogen storage material under 80% ambient humidity. The temperature was set to 320K and the pressure to 100 bar, and the hydrogen storage material was degassed under vacuum for 12 hours. Three hydrogen absorption and desorption kinetic tests were conducted.

[0038] Comparative Example 1 1. Activated carbon is activated at 500℃ for 2 hours in a N2 atmosphere to remove surface impurities and improve the micropore opening rate.

[0039] 2.5A zeolite was soaked in 1M NaCl solution for 24 hours, washed with water until neutral, and dried at 150℃ for 4 hours to enhance surface polarity.

[0040] 3. Mix AC and zeolite at a mass ratio of 1:3, add to a planetary ball mill (ball-to-material ratio 10:1), and ball mill at 300 r / min for 4 h to form uniform micron-sized AC-zeolite composite powder.

[0041] 4. Mix PVDF and N-methylpyrrolidone (NMP) at a mass ratio of 1:9 and stir for 2 hours to form a colloidal binder.

[0042] 5. The AC and zeolite composite powder and binder are mixed at a mass ratio of 95:5. The mixture is then spray-dried at a pressure of 1.0 MPa. The slurry is sprayed out through the atomizing nozzle and rapidly solidified into spherical particles in a drying tower. The spherical particles are dried in a 60°C oven for 12 hours to remove moisture. They are then heated to 100°C at a rate of 5°C / min in a N2 atmosphere to form a porous structure.

[0043] Performance testing and optimization: Same as in Example 1.

[0044] Material properties Figure 1 The pore size distribution curves of the composite materials of Example 1 and Comparative Example 1 are calculated based on the 77K nitrogen adsorption-desorption curve. The pore size distribution and pore volume data of the composite materials obtained in Example 1 and Comparative Example 1, compared with traditional activated carbon-zeolite materials, were calculated and analyzed. The results show that the number of pores in the treated composite material is significantly increased compared with the traditional material, with a significant increase in the number of micropores (pore size <2nm) and mesopores (pore size 2-50nm). This structural feature is beneficial for increasing hydrogen adsorption sites and adsorption pathways, thereby improving the material's hydrogen adsorption performance.

[0045] Figure 2 and Figure 3The hydrogen adsorption-desorption isotherms of the composite material obtained in Example 1 and Comparative Example 1, and the traditional activated carbon-zeolite hydrogen storage material are presented respectively. Test data show that under operating conditions of 80% relative humidity, 320K temperature, and 100bar pressure, the hydrogen storage capacity of the composite material is significantly improved compared to the traditional material. Three consecutive adsorption-desorption cycle tests show that the composite material maintains good hydrogen storage performance stability, demonstrating its potential application value as a high-efficiency hydrogen storage material in humid environments.

Claims

1. A method for preparing a hydrogen adsorption and storage composite material for use in high-humidity and high-temperature environments in coal mines, characterized in that, include: Step 1: Activate the activated carbon to obtain pretreated activated carbon; The zeolite was soaked in NaCl solution and then dried to obtain pretreated zeolite. Step 2: Mix ZIF-8, pretreated activated carbon and zeolite, add to a ball mill for ball milling to obtain composite powder; Step 3: Mix the composite powder obtained in Step 2 with the binder and stir. Then, use spray drying to solidify it into spheres. After drying, heat it to form a porous structure to obtain a hydrogen adsorption and storage composite material for use in the high humidity and heat environment of coal mines.

2. The method for preparing a hydrogen adsorption and storage composite material for high humidity and heat environments in coal mines according to claim 1, characterized in that, The activation conditions described in step one are as follows: activation is carried out in an N2 atmosphere, with an activation temperature of 500℃-1000℃ and an activation time of 1h-3h.

3. The method for preparing a hydrogen adsorption and storage composite material for high humidity and heat environments in coal mines according to claim 1, characterized in that, The soaking time in step one is 6-24 hours, the temperature of the NaCl solution is controlled above 60℃, and continuous stirring is carried out during the soaking period. The drying temperature is 100℃-150℃, and the drying time is 2-6 hours.

4. The method for preparing a hydrogen adsorption and storage composite material for high humidity and heat environments in coal mines according to claim 1, characterized in that, In step two, the mass ratio of ZIF-8, pretreated activated carbon, and zeolite is 2:2:

6.

5. The method for preparing a hydrogen adsorption and storage composite material for high humidity and heat environments in coal mines according to claim 1, characterized in that, The conditions for ball milling in step two are: ball-to-material ratio (8-12):1, rotation speed of 200r / min-400r / min, and ball milling for more than 4 hours.

6. The method for preparing a hydrogen adsorption and storage composite material for high humidity and heat environments in coal mines according to claim 1, characterized in that, The adhesive mentioned in step three is a mixture of PVDF and N-methylpyrrolidone.

7. The method for preparing a hydrogen adsorption and storage composite material for high humidity and heat environments in coal mines according to claim 1, characterized in that, The mass ratio of the composite powder and binder mentioned in step three is (92-95):(5-8).

8. The method for preparing a hydrogen adsorption and storage composite material for high humidity and heat environments in coal mines according to claim 1, characterized in that, The conditions for spray drying described in step three are: atomization pressure set ≥0.5MPa.

9. The hydrogen adsorption and storage composite material for high humidity and heat environments in coal mines obtained by the preparation method according to claim 1, characterized in that, The composite material described above has a multi-level porous structure that combines micropores and mesopores.

10. The application of the composite material of claim 9 in hydrogen adsorption and storage in high-humidity and high-temperature environments such as coal mines, natural gas extraction, and oil refining.

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