Fused salt pyrolysis recovery system and method for waste hydrogen storage cylinder

Abstract

The invention relates to the technical field of molten salt pyrolysis, in particular to a molten salt pyrolysis recovery system and method for a waste hydrogen storage cylinder. The system comprises a first reaction tank provided with first target fused salt; the rotating device is used for driving the waste hydrogen storage cylinder to rotate along the axis of the rotating device, the axis of the waste hydrogen storage cylinder is horizontally arranged above the liquid level of the first target fused salt, the outer layer of the waste hydrogen storage cylinder is a carbon fiber composite material, the inner layer of the waste hydrogen storage cylinder is a plastic liner or a metal liner, and microwave dielectric balls are arranged in the inner layer of the waste hydrogen storage cylinder; the lowermost outer layer of the waste hydrogen storage cylinder is immersed in the first target molten salt, so that the outer layer of the waste hydrogen storage cylinder is pyrolyzed by utilizing the first target molten salt and the microwave dielectric balls, and resin in the carbon fiber composite material is removed; and the filament collecting device is used for collecting filament fibers generated by the waste hydrogen storage cylinder. According to the scheme, fused salt pyrolysis recovery of the waste hydrogen storage cylinder can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of molten salt pyrolysis, and in particular to a molten salt pyrolysis recovery system and method for discarded hydrogen storage cylinders. Background Art

[0002] As an important clean energy carrier, hydrogen plays an important role in addressing climate change. The booming development of hydrogen energy also puts forward higher requirements for hydrogen storage, accompanied by new demands for recycling of hydrogen storage devices. As the most mature hydrogen storage technology today, pressure cylinder storage has significant advantages in hydrogen storage and transportation.

[0003] At present, the mature hydrogen storage cylinders on the market are Type III and Type IV cylinders, which use steel, aluminum or plastic as the inner liner, and the outer layer is made of carbon fiber composite material wrapped around the storage tank, which can increase the working pressure of the cylinder and reduce its weight, thereby having a higher hydrogen storage density.

[0004] However, the component separation technology of waste hydrogen storage cylinders is not mature yet, and there is a problem of low separation efficiency. Based on this, there is an urgent need for a molten salt pyrolysis recovery system and method for waste hydrogen storage cylinders to solve the above technical problems. Summary of the invention

[0005] The embodiments of the present invention provide a molten salt pyrolysis recovery system and method for discarded hydrogen storage cylinders, which can realize the molten salt pyrolysis recovery of discarded hydrogen storage cylinders.

[0006] In a first aspect, an embodiment of the present invention provides a molten salt pyrolysis recovery system for discarded hydrogen storage cylinders, comprising:

[0007] A first reaction tank is provided with a first target molten salt;

[0008] A rotating device, used for driving the abandoned hydrogen storage cylinder to rotate along its axis, the axis of the abandoned hydrogen storage cylinder is horizontally arranged above the liquid surface of the first target molten salt, the outer layer of the abandoned hydrogen storage cylinder is a carbon fiber composite material, the inner layer is a plastic liner or a metal liner, the inner layer of the abandoned hydrogen storage cylinder is equipped with a microwave dielectric ball, the outer layer of the abandoned hydrogen storage cylinder at the bottom is immersed in the first target molten salt, so as to use the first target molten salt and the microwave dielectric ball to pyrolyze the outer layer of the abandoned hydrogen storage cylinder, thereby removing the resin in the carbon fiber composite material;

[0009] The filament collecting device is used to collect the filament fibers produced by the discarded hydrogen storage cylinder.

[0010] In a second aspect, an embodiment of the present invention provides a method for recovering waste hydrogen storage cylinders by molten salt pyrolysis, comprising:

[0011] A microwave dielectric ball is placed in an abandoned hydrogen storage cylinder; wherein the outer layer of the abandoned hydrogen storage cylinder is a carbon fiber composite material, and the inner layer is a plastic liner or a metal liner;

[0012] The abandoned hydrogen storage cylinder containing the microwave dielectric ball is horizontally arranged above the liquid surface of the first target molten salt; wherein the outer layer of the abandoned hydrogen storage cylinder at the bottom is immersed in the first target molten salt;

[0013] The waste hydrogen storage cylinder is rotated, and the outer layer of the waste hydrogen storage cylinder is pyrolyzed by using the first target molten salt and the microwave dielectric ball to remove the resin in the carbon fiber composite material;

[0014] The filament fibers generated by the discarded hydrogen storage cylinder are collected by a filament collecting device located above the discarded hydrogen storage cylinder.

[0015] The embodiment of the present invention provides a molten salt pyrolysis recovery system and method for discarded hydrogen storage cylinders. By introducing a molten salt method, the catalytic effect of the molten salt system is used in the molten salt system to promote the removal of the resin binder in the outer layer of carbon fiber composite material and separate the filament fibers. Microwave technology is introduced to make the heating of the inner and outer layers of the cylinder more uniform, improve the heat transfer process, and make it less likely for the thermal decomposition process of the inner plastic liner to cause local uneven heating and produce residual carbon that adheres to the fiber material. The steel and aluminum materials of the inner layer are inert substances in the molten salt system and will not undergo chemical reactions, thereby effectively retaining the structural integrity. Therefore, the above technical solution can achieve molten salt pyrolysis recovery of discarded hydrogen storage cylinders. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 It is a structural schematic diagram of a molten salt pyrolysis recovery system for discarded hydrogen storage cylinders provided in an embodiment of the present invention;

[0018] Figure 2 It is a schematic diagram of the positions of the discarded hydrogen storage cylinder, the first reaction pool, the rotating device and the wire collecting device provided in an embodiment of the present invention;

[0019] Figure 3 It is a schematic flow chart of a method for molten salt pyrolysis recovery of discarded hydrogen storage cylinders provided in an embodiment of the present invention.

[0020] Reference numerals:

[0021] 10-discarded hydrogen storage cylinder; 1-first reaction tank; 2-rotating device; 3-wire collecting device; 4-second reaction tank; 5-drying device; 6-condensing device; 7-combustion device; 8-washing device. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0023] like Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a molten salt pyrolysis recovery system for discarded hydrogen storage cylinders, comprising a first reaction tank 1, a rotating device 2 and a wire collecting device 3, wherein:

[0024] The first reaction tank 1 is provided with a first target molten salt;

[0025] The rotating device 2 is used to drive the abandoned hydrogen storage cylinder 10 to rotate along its axis. The axis of the abandoned hydrogen storage cylinder 10 is horizontally arranged above the liquid surface of the first target molten salt. The outer layer of the abandoned hydrogen storage cylinder 10 is a carbon fiber composite material, and the inner layer is a plastic liner or a metal liner. The inner layer of the abandoned hydrogen storage cylinder 10 is equipped with a microwave dielectric ball. The outer layer of the abandoned hydrogen storage cylinder 10 at the bottom is immersed in the first target molten salt, so that the outer layer of the abandoned hydrogen storage cylinder 10 is pyrolyzed by using the first target molten salt and the microwave dielectric ball, thereby removing the resin in the carbon fiber composite material.

[0026] The filament collecting device 3 is used to collect the filament fibers generated by the discarded hydrogen storage cylinder 10 .

[0027] In this embodiment, by introducing the molten salt method, the catalytic effect of the molten salt system is used in the molten salt system to promote the removal of the resin binder in the outer layer of carbon fiber composite material and separate the filament fibers. Microwave technology is introduced to make the heating of the inner and outer layers of the gas cylinder more uniform, improve the heat transfer process, and make it less likely for the thermal decomposition process of the inner plastic liner to cause local uneven heating and produce residual carbon that adheres to the fiber material. The steel and aluminum materials of the inner layer are inert substances in the molten salt system and will not react chemically, thereby effectively retaining the structural integrity. Therefore, the above technical solution can realize the molten salt pyrolysis recovery of discarded hydrogen storage cylinders.

[0028] It should be noted that the carbon fiber of the outer liner can absorb microwaves, so microwaves are introduced into the first reaction pool 1 to strengthen the thermal decomposition of the outer liner; the purpose of microwaves is to strengthen the thermal decomposition of the plastic inner liner, optimize the reaction process, and make the plastic decomposition products more homogeneous, so that the quality of the pyrolysis products is not too low. For convenience, a ball cage is set on the outside of the microwave dielectric ball. The size of the ball cage is similar to that of the bottle mouth. After being inserted, it can be opened from the inside, making it easy to enter but difficult to exit.

[0029] In some embodiments, the material of the microwave dielectric ball is a ferrite microwave absorbing material, such as lithium cadmium ferrite, lithium zinc ferrite, nickel cadmium ferrite and ceramic ferrite. The density of the cage + microwave dielectric ball is controlled at 2g / cm 3 , the power of microwave radiation is set to 2000-2500MHz.

[0030] In one embodiment of the present invention, the first target molten salt includes nitrate, carbonate (such as K2CO3-Na2CO3-Li2CO3) and alkaline molten salt (such as NaOH-KOH), and the heating temperature of the first target molten salt is 400-500°C.

[0031] In this embodiment, the resin can be removed violently by utilizing the oxidizing property of nitrates.

[0032] In some embodiments, the nitrate may include NaNO2-NaNO3-KNO3, NaNO2-NaNO3, which are not specifically limited herein.

[0033] In one embodiment of the present invention, the above-mentioned system also includes a second reaction tank 4, which is provided with a second target molten salt. When the inner layer of the discarded hydrogen storage cylinder 10 is a plastic liner, the second target molten salt is used to mix with the plastic liner to utilize the second target molten salt to pyrolyze the plastic liner.

[0034] In this embodiment, considering that the plastic liner can also undergo a violent thermal decomposition process in the molten salt system, thereby precipitating liquid and gas phase components, by selecting a suitable molten salt system, the plastic can be thermally decomposed to generate hydrocarbon-rich oil, which has the potential to be recycled and reused to produce plastics, and the gas generated can be used to provide heat for the drying device through a combustion device.

[0035] In one embodiment of the present invention, the second target molten salt includes chloride salt (such as KCl-ZnCl2), carbonate (such as K2CO3-Na2CO3-Li2CO3) and alkaline molten salt (such as NaOH-KOH, NaOH-Na2CO3), and the heating temperature of the second target molten salt is 450-550°C.

[0036] In this embodiment, with the help of the good catalytic and deoxidation properties of the second target molten salt, the plastic is converted into rich chain hydrocarbon oil to regenerate rich chain hydrocarbon oil, which can be further synthesized to generate plastic raw materials. After graded condensation, the chain hydrocarbon component content in the rich hydrocarbon oil exceeds 90%, which can be reprocessed as a synthetic raw material to prepare a plastic liner.

[0037] In one embodiment of the present invention, when the second target molten salt is pyrolyzed, the pyrolysis atmosphere includes a preset percentage of water vapor, and the preset percentage is 3-7%.

[0038] In this embodiment, a preset percentage of water vapor is introduced into the second target molten salt to generate more H free radicals, thereby inhibiting the cyclization of chain hydrocarbon products generated by plastic pyrolysis to generate aromatic components. In addition, the gasification reaction can also be controlled by controlling the pyrolysis temperature below 600°C.

[0039] It should be noted that the related art may have a scheme of introducing water vapor into the molten salt, but its function is gasification, and the temperature is higher than 600°C, which mainly provides OH free radicals to react with C+·OH→C(O)+H·, and gasifies the coke to generate gas. However, in the second target molten salt system of the present invention, when the plastic reacts with the molten salt, the yield of coke is less than 5%, and the yield of coke is very low, so the above reaction will not occur.

[0040] In one embodiment of the present invention, the system further includes a drying device 5, a condensing device 6, a combustion device 7 and a washing device 8. The drying device 5 is used to dry and dehydrate the volatile matter produced by the pyrolysis of the second target molten salt. The condensing device 6 is used to grade and condense the products after drying and dehydration to separate the hydrocarbon-rich components. The combustion device 7 is used to burn the non-condensable gas and supply the heat generated by the combustion to the drying device 5. The washing device 8 is used to wash the collected fibers with an organic solvent to obtain clean fibers.

[0041] In this embodiment, the non-condensable gas includes combustible gases such as CH4, CO, and H2, with a calorific value of 15-20 MJ / m 3 .

[0042] It should be pointed out that the specific structures of the above-mentioned entity devices are not shown in the embodiments of the present invention, but those skilled in the art can understand that the structures with the functions of the entity devices are within the protection scope of the present invention based on their functions, and the specific structures of the entity devices are not repeated here.

[0043] In addition, if Figure 3 As shown, an embodiment of the present invention also provides a molten salt pyrolysis recovery method for discarded hydrogen storage cylinders, comprising:

[0044] Step S1, loading a microwave dielectric ball into a discarded hydrogen storage cylinder; wherein the outer layer of the discarded hydrogen storage cylinder is a carbon fiber composite material, and the inner layer is a plastic liner or a metal liner;

[0045] Step S2, horizontally setting the abandoned hydrogen storage cylinder containing the microwave dielectric ball above the liquid surface of the first target molten salt; wherein the abandoned hydrogen storage cylinder is at the bottom outer layer immersed in the first target molten salt;

[0046] Step S3, rotating the discarded hydrogen storage cylinder, and using the first target molten salt and the microwave dielectric ball to pyrolyze the outer layer of the discarded hydrogen storage cylinder to remove the resin in the carbon fiber composite material;

[0047] Step S4: using a filament collection device located above the discarded hydrogen storage cylinder to collect the filament fibers generated by the discarded hydrogen storage cylinder.

[0048] In one embodiment of the present invention, the first target molten salt includes nitrate, carbonate and alkaline molten salt, and the heating temperature of the first target molten salt is 400-500°C.

[0049] In one embodiment of the present invention, when the inner layer of the discarded hydrogen storage cylinder is a plastic liner, it also includes:

[0050] The plastic liner is immersed in a second target molten salt to pyrolyze the plastic liner using the second target molten salt; wherein the second target molten salt includes chloride salt, carbonate salt and alkaline molten salt, and the heating temperature of the second target molten salt is 450-550°C.

[0051] In one embodiment of the present invention, when the plastic liner is pyrolyzed using the second target molten salt, a preset percentage of water vapor is introduced into the second target molten salt; wherein the preset percentage is 3-7%.

[0052] In one embodiment of the present invention, it also includes:

[0053] The collected fibers are washed with an organic solvent to obtain clean fibers.

[0054] In one embodiment of the present invention, after the plastic liner is pyrolyzed by using the second target molten salt, the method further includes:

[0055] Drying and dehydrating the volatile matter produced by pyrolysis of the second target molten salt;

[0056] The dried and dehydrated products are graded and condensed to separate the hydrocarbon-rich components, and the non-condensable gases are introduced into a combustion device for combustion; wherein the heat generated by the combustion of the combustion device is used for drying and dehydration.

[0057] It can be understood that the method embodiment and system embodiment provided by the present invention are based on the same inventive concept and have the same beneficial effects, and the beneficial effects of the method embodiment will not be elaborated herein.

[0058] It should be noted that, in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "comprise a ..." do not exclude the presence of other identical factors in the process, method, article or device including the elements.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A molten salt pyrolysis recovery system for discarded hydrogen storage cylinders, characterized in that: include: A first reaction tank is provided with a first target molten salt; A rotating device, used for driving the abandoned hydrogen storage cylinder to rotate along its axis, the axis of the abandoned hydrogen storage cylinder is horizontally arranged above the liquid surface of the first target molten salt, the outer layer of the abandoned hydrogen storage cylinder is a carbon fiber composite material, the inner layer is a plastic liner or a metal liner, the inner layer of the abandoned hydrogen storage cylinder is equipped with a microwave dielectric ball, the outer layer of the abandoned hydrogen storage cylinder at the bottom is immersed in the first target molten salt, so as to use the first target molten salt and the microwave dielectric ball to pyrolyze the outer layer of the abandoned hydrogen storage cylinder, thereby removing the resin in the carbon fiber composite material; The filament collecting device is used to collect the filament fibers produced by the discarded hydrogen storage cylinder.

2. The system according to claim 1, characterized in that The first target molten salt includes nitrate, carbonate and alkaline molten salt, and the heating temperature of the first target molten salt is 400-500°C.

3. The system according to claim 1, characterized in that It also includes a second reaction tank, which is provided with a second target molten salt. When the inner layer of the discarded hydrogen storage cylinder is a plastic liner, the second target molten salt is used to mix with the plastic liner to pyrolyze the plastic liner using the second target molten salt.

4. The system according to claim 3, characterized in that The second target molten salt includes chloride salt, carbonate salt and alkaline molten salt, and the heating temperature of the second target molten salt is 450-550° C.; and / or, When the second target molten salt is pyrolyzed, the pyrolysis atmosphere includes a preset percentage of water vapor, and the preset percentage is 3-7%.

5. The system according to claim 4, characterized in that It also includes a drying device, a condensing device, a combustion device and a washing device. The drying device is used to dry and dehydrate the volatile matter produced by the pyrolysis of the second target molten salt. The condensing device is used to grade and condense the products after drying and dehydration to separate the hydrocarbon-rich components. The combustion device is used to burn the non-condensable gas and supply the heat generated by the combustion to the drying device. The washing device is used to wash the collected fibers with an organic solvent to obtain clean fibers.

6. A method for recovering discarded hydrogen storage cylinders by molten salt pyrolysis, characterized in that: include: A microwave dielectric ball is placed in an abandoned hydrogen storage cylinder; wherein the outer layer of the abandoned hydrogen storage cylinder is a carbon fiber composite material, and the inner layer is a plastic liner or a metal liner; The abandoned hydrogen storage cylinder containing the microwave dielectric ball is horizontally arranged above the liquid surface of the first target molten salt; wherein the outer layer of the abandoned hydrogen storage cylinder at the bottom is immersed in the first target molten salt; The waste hydrogen storage cylinder is rotated, and the outer layer of the waste hydrogen storage cylinder is pyrolyzed by using the first target molten salt and the microwave dielectric ball to remove the resin in the carbon fiber composite material; The filament fibers generated by the discarded hydrogen storage cylinder are collected by a filament collecting device located above the discarded hydrogen storage cylinder.

7. The method according to claim 6, characterized in that The first target molten salt includes nitrate, carbonate and alkaline molten salt, and the heating temperature of the first target molten salt is 400-500°C.

8. The method according to claim 6, characterized in that When the inner layer of the discarded hydrogen storage cylinder is a plastic liner, it also includes: The plastic liner is immersed in a second target molten salt to pyrolyze the plastic liner using the second target molten salt; wherein the second target molten salt includes chloride salt, carbonate salt and alkaline molten salt, and the heating temperature of the second target molten salt is 450-550°C.

9. The method according to claim 8, characterized in that When the plastic liner is pyrolyzed by using the second target molten salt, a preset percentage of water vapor is introduced into the second target molten salt; wherein the preset percentage is 3-7%.

10. The method according to claim 9, characterized in that Also includes: The collected fibers are washed with an organic solvent to obtain clean fibers; and / or, After the plastic liner is pyrolyzed by using the second target molten salt, the method further includes: Drying and dehydrating the volatile matter produced by pyrolysis of the second target molten salt; The dried and dehydrated products are graded and condensed to separate the hydrocarbon-rich components, and the non-condensable gases are introduced into a combustion device for combustion; wherein the heat generated by the combustion of the combustion device is used for drying and dehydration.

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