Catalyst for fuel-free low-temperature oxygen candle and preparation method thereof

Abstract

The invention relates to a catalyst for a fuel-free low-temperature oxygen candle, which is prepared by taking a nano oxide catalyst of iron, cobalt, nickel or manganese as a main catalyst, adding 10-25wt% of high-thermal-conductivity carbon-based nano material and mixing, and the high-thermal-conductivity carbon-based nano material is any one of graphene, carbon nano tube or nano graphite. The oxygen candle prepared by adopting the catalyst disclosed by the invention does not need to use metal fuel, can be continuously combusted in an ultralow-temperature environment of-55 DEG C until oxygen release is finished, and is high in safety, strong in reliability, low in heat production and stable in oxygen release, released gas does not contain chlorine, and residues are not easy to flow after combustion.

Description

Technical Field

[0001] The invention belongs to the technical field of solid chemical oxygen production and relates to a catalyst for chlorate oxygen candles. Background Art

[0002] Oxygen candles are emergency rescue devices that generate oxygen through the thermal decomposition of oxygen-enriched chlorates or perchlorates under a catalyst. Their notable features include long-term storage stability, compact size, and high density, allowing them to store three times the oxygen of an equivalent volume of compressed oxygen. As solid chemical oxygen devices, oxygen candles have become widely used as a lifesaving emergency oxygen source in shelters, mines, aerospace, submarines, hospitals, and other civilian applications.

[0003] In pursuit of sustained and stable combustion of oxygen candles, CN 107619021A and CN 107867675A, among others, enhance the combustion effect by adding metal powder fuel to the oxygen-producing column of the oxygen candle. However, this method inevitably causes a significant increase in the heat of the oxygen candle device, which may cause the temperature of the oxygen candle wall to rise sharply. If effective thermal management measures are lacking, excessive heat accumulation inside the oxygen candle will not only reduce operational efficiency but may also activate the chlorate side reaction, generating harmful chlorine gas.

[0004] Therefore, carefully controlling the type of fuel, the amount of catalyst added, and the thermal management strategy becomes the key to designing and preparing oxygen candles.

[0005] The catalyst not only promotes the efficient oxygen production of oxygen candles, but also acts as a safety valve to ensure their stable operation under extreme conditions. Currently, most oxygen candles have difficulty maintaining stable and continuous combustion at ultra-low temperatures, and this problem needs to be solved urgently.

[0006] CN 114906815A discloses an ultra-low-temperature nano-solid oxygen candle oxygen generator. By adding an appropriate amount of nano-iron oxide or cobalt catalyst to chlorate, the low-temperature combustion performance of the oxygen candle is significantly improved, enabling it to burn continuously in an environment of -40°C. This advancement highlights the important value of catalysts in broadening the applicable temperature range of oxygen candles and ensuring their safe and efficient operation.

[0007] However, the lowest combustion temperature of this oxygen candle can only reach -40°C, and even after further lowering the temperature, it still cannot achieve stable and sustained combustion. Therefore, in-depth research and optimization of catalyst application are crucial to improving the low-temperature combustion performance of oxygen candles and overcoming the technical bottlenecks of existing oxygen candle applications. Summary of the Invention

[0008] The purpose of the present invention is to provide a fuel-free low-temperature oxygen candle catalyst for the preparation of oxygen candles in view of the deficiencies in the prior art, so that the oxygen candles can still maintain efficient oxygen release performance under low temperature conditions.

[0009] The catalyst for fuel-free low-temperature oxygen candles of the present invention is a catalyst obtained by adding 10-25wt% of high thermal conductivity carbon-based nanomaterials to a nano-oxide catalyst of iron, cobalt, nickel or manganese as a main catalyst.

[0010] The oxygen candle using the catalyst of the present invention does not require the addition of metal fuel and can achieve continuous combustion in an ultra-low temperature environment of -55°C until the oxygen release is completed. It has high safety, strong reliability, low heat generation, stable oxygen release and no chlorine in the released gas.

[0011] The main catalyst is used to reduce the decomposition temperature of the chlorate oxygen source, thereby lowering the surface temperature of the oxygen candle. The main catalyst of the present invention is preferably selected from one or a combination of nano-ferroferric oxide, nano-cobalt trioxide, nano-cobalt trioxide, nano-cobaltous oxide, nano-manganese dioxide, or nano-nickel oxide.

[0012] The present invention has found that, while achieving the same oxygen release rate, by adding an appropriate amount of high thermal conductivity carbon-based nanomaterials to the main catalyst, the normal combustion of the oxygen candle can be ensured without using metal fuel, thereby significantly increasing the proportion of chlorate in the oxygen candle and increasing the amount of oxygen released.

[0013] Specifically, the high thermal conductivity carbon-based nanomaterial is any one of graphene, carbon nanotubes or nanographite.

[0014] Furthermore, the present invention also provides a method for preparing the catalyst for the fuel-free low-temperature oxygen candle, specifically, mixing the main catalyst and the high thermal conductivity carbon-based nanomaterial in the mass ratio, adding an appropriate amount of water and ball milling to mix them evenly, and then drying and crushing to obtain a catalyst with a particle size of less than 500nm.

[0015] The amount of water added is preferably 10-30% of the mass of the main catalyst.

[0016] The ball milling mixing is specifically carried out at a rotation speed of 200-500 rpm, and the preferred ball milling time is 0.5-3 h.

[0017] The present invention has at least one of the following technical effects:

[0018] 1) The solid oxygen candle oxygen-generating pellets prepared using the catalyst of the present invention do not contain any metal fuel and can continuously burn the pellets, continuously supplying oxygen until combustion is complete, thereby improving safety and reliability;

[0019] 2) The solid oxygen candle oxygen-generating pellets prepared using the catalyst of the present invention can achieve continuous oxygen supply at an ultra-low temperature of -55°C until the pellets are completely burned. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a volume flow-time curve diagram when the oxygen-producing charge is burned in Application Example 1. Implementation Method

[0021] The following examples are only used to more clearly illustrate the technical solutions of the present invention so that those skilled in the art can fully understand and utilize the present invention.

[0022] However, the present invention can be implemented in many other ways different from those described in the following embodiments, and those skilled in the art can also make similar improvements without violating the connotation of the present invention. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0023] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art. The terms used in the present invention specification are only for describing specific embodiments and are not intended to limit the present invention.

[0024] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0025] The terms "multiple", "multiple", "multiple times", "multiple groups", etc. used in the present invention, unless otherwise specified, refer to a quantity greater than or equal to 2; "above" includes the number itself, such as "more than two" includes two, three or more.

[0026] The term "preferably" used in the present invention is only used to describe an implementation method or example with better effects, and does not constitute a limitation on the scope of protection of the present invention.

[0027] The production processes, experimental methods or detection methods involved in the embodiments of the present invention, unless otherwise specified, are conventional methods in the prior art, and their names and / or abbreviations are conventional names in the field and are very clear and unambiguous in the relevant fields of use. Those skilled in the art can understand the conventional process steps based on the names and apply the corresponding equipment, and implement them according to conventional conditions or conditions recommended by the manufacturer, or refer to experimental methods known in the art.

[0028] The various instruments, equipment, raw materials or reagents used in the embodiments of the present invention are not particularly limited in their sources and are all conventional products that can be purchased through regular commercial channels or prepared according to conventional methods well known to those skilled in the art.

[0029] In the embodiment of the present invention, the catalyst for fuel-free low-temperature oxygen candles is prepared by the following method:

[0030] 1) Using nano-oxide catalysts of iron, cobalt, nickel or manganese as the main catalyst, add 10-25% of its mass of high thermal conductivity carbon-based nanomaterials and 10-30% of water, and ball mill at a speed of 200-500 rpm for 0.5-3 hours;

[0031] 2) Dry the ball-milled material at 100-150°C for 2-5 hours;

[0032] 3) Use a nano-grinder to crush the dried material to prepare a catalyst with a particle size of less than 500 nm.

[0033] In a specific embodiment, the main catalyst is preferably selected from one or a combination of nano-ferroferric oxide, nano-cobaltic oxide, nano-cobaltous oxide, nano-cobaltous oxide, nano-cobaltous oxide, nano-manganese dioxide or nano-nickel oxide.

[0034] In a specific embodiment, the high thermal conductivity carbon-based nanomaterial can be any one of graphene, carbon nanotubes or nanographite, but graphene is most preferably used.

[0035] The present invention has no special requirements for the graphene used as a raw material, but further, the graphene may preferably be graphene with an oxygen content of less than 0.5%.

[0036] Unless otherwise specified, the amounts of raw material components and measurement parameters such as temperature and time involved in the embodiments of the present invention may have slight deviations within the range of weighing or measurement accuracy, and acceptable deviations caused by instrument testing accuracy or operating accuracy are allowed. Example

[0037] Example 1

[0038] Weigh 9 g of nano-ferroferric oxide and 1 g of graphene and add them into a ball mill, add 1 g of water, and mix by ball milling at a speed of 200 rpm for 1 h.

[0039] The ball-milled material was taken out and placed in an oven at 120°C to dry for 5 h.

[0040] The dried material is crushed by a nano-grinder to a particle size of less than 500 nm to prepare a catalyst.

[0041] Example 2

[0042] 8.5 g of nano-cobaltous oxide and 1.5 g of graphene were weighed and added into a ball mill, 2 g of water was added, and the mixture was ball-milled at a speed of 350 rpm for 1.5 h.

[0043] The ball-milled material was taken out and placed in an oven at 110°C to dry for 5 h.

[0044] The dried material is crushed by a nano-grinder to a particle size of less than 500 nm to prepare a catalyst.

[0045] Example 3

[0046] 8.5 g of nano-manganese dioxide and 2 g of carbon nanotubes were weighed and added into a ball mill, 2.5 g of water was added, and the mixture was ball-milled at a rotation speed of 450 rpm for 0.5 h.

[0047] The ball-milled material was taken out and placed in an oven at 130°C to dry for 3 h.

[0048] The dried material is crushed by a nano-grinder to a particle size of less than 500 nm to prepare a catalyst.

[0049] Application Example 1

[0050] A solid oxygen candle oxygen generating pellet was prepared using the catalyst of Example 1. 97 g of sodium chlorate, 0.4 g of potassium perchlorate, 2.5 g of catalyst, and 0.1 g of lithium peroxide were weighed and placed in a mixer for dry mixing until uniformly mixed.

[0051] The mixed raw materials are poured into a custom mold and pressed on a tablet press at 10T / cm 2 The density of the molded product is 2.1g / cm 3 Oxygen-producing column.

[0052] The solid oxygen generator is packaged with oxygen-producing pellets and tested as follows:

[0053] 1) Place the solid oxygen generator in an ultra-low temperature freezing test chamber, freeze it at -55℃ for 48 hours, and then conduct a combustion performance test at -55℃ in the ultra-low temperature freezing test chamber. The oxygen-producing charge can burn completely. The combustion process is monitored by gas flow detection method. Figure 1 As shown, the oxygen production volume flow-time curve is stable, and the oxygen production rate is as high as 99%; the generated gas meets the requirements of medical and aviation breathing oxygen (GB 8982-2009).

[0054] 2) During the combustion process, the wall temperature of the solid oxygen generator is 132°C, and the reaction products after combustion are in the form of layered accumulation without any holes or flow.

[0055] 3) The gas produced during the combustion of the solid oxygen generator was tested in accordance with the method specified in GB / T 11736-1989, "Standard Method for the Hygienic Examination of Chlorine in the Atmosphere of Residential Areas - Methyl Orange Spectrophotometric Method," and no chlorine was detected.

[0056] Application Example 2

[0057] The solid oxygen candle oxygen generating pellets were prepared using the catalyst of Example 2. 97 g of sodium chlorate, 2.5 g of catalyst, and 0.5 g of barium peroxide were weighed and placed in a mixer for dry mixing until uniformly mixed.

[0058] The mixed raw materials are poured into a custom mold and pressed on a tablet press at 10T / cm 2 The density of the mold is 2.0g / cm 3 Oxygen-producing column.

[0059] The solid oxygen generator is packaged with oxygen-producing pellets and tested as follows:

[0060] 1) The solid oxygen generator was placed in an ultra-low temperature freezing chamber and frozen at -55°C for 48 hours. Combustion performance testing was then conducted at -55°C within the chamber, demonstrating complete combustion of the oxygen-producing charge. Gas flow rate monitoring of the combustion process revealed a stable oxygen volume flow-time curve, with an oxygen production rate of 98.5%. The generated gas met the requirements for medical and aviation breathing oxygen (GB 8982-2009).

[0061] 2) During the combustion process, the wall temperature of the solid oxygen generator is 135°C, and the reaction products after combustion are in the form of layered accumulation without any holes or flow.

[0062] 3) The gas produced during the combustion of the solid oxygen generator was tested in accordance with the method specified in GB / T 11736-1989, "Standard Method for the Hygienic Examination of Chlorine in the Atmosphere of Residential Areas - Methyl Orange Spectrophotometric Method," and no chlorine was detected.

[0063] Application Example 3

[0064] A solid oxygen candle oxygen generating pellet was prepared using the catalyst of Example 3. 97 g of sodium chlorate, 0.5 g of potassium perchlorate, 2 g of catalyst, and 0.5 g of barium peroxide were weighed and placed in a mixer for dry mixing until uniformly mixed.

[0065] The mixed raw materials are poured into a custom mold and pressed on a tablet press at 10T / cm 2 The density of the molded product is 2.3g / cm 3 Oxygen-producing column.

[0066] The solid oxygen generator is packaged with oxygen-producing pellets and tested as follows:

[0067] 1) The solid oxygen generator was placed in an ultra-low temperature freezing chamber and frozen at -55°C for 48 hours. Combustion performance testing was then conducted at -55°C within the chamber, demonstrating complete combustion of the oxygen-producing charge. Gas flow rate monitoring of the combustion process revealed a stable oxygen volume flow-time curve, with an oxygen production rate of 98.5%. The generated gas met the requirements for medical and aviation breathing oxygen (GB 8982-2009).

[0068] 2) During the combustion process, the wall temperature of the solid oxygen generator is 135°C, and the reaction products after combustion are in the form of layered accumulation without any holes or flow.

[0069] 3) The gas produced during the combustion of the solid oxygen generator was tested in accordance with the method specified in GB / T 11736-1989, "Standard Method for the Hygienic Examination of Chlorine in the Atmosphere of Residential Areas - Methyl Orange Spectrophotometric Method," and no chlorine was detected.

[0070] Comparative Example 1

[0071] Weigh 97 g of sodium chlorate, 0.5 g of potassium perchlorate, 2.0 g of nano-cobalt tetroxide, and 0.5 g of lithium peroxide, place them in a mixer and dry mix them until they are uniformly mixed.

[0072] The mixed raw materials are poured into a custom mold and pressed on a tablet press at 10T / cm 2 The density of the molded product is 2.1g / cm 3 Oxygen-producing column.

[0073] The oxygen-producing candle core was packaged into a solid oxygen generator and placed in an ultra-low temperature freezing test chamber. After being frozen at -40°C for 48 hours, an oxygen production test was carried out at -40°C in the ultra-low temperature freezing test chamber. The results showed that the oxygen candle core could burn completely and the oxygen production rate could reach 97%. However, the wall temperature of the solid oxygen generator reached as high as 168°C during the combustion process.

[0074] The packaged solid oxygen generator was then placed in an ultra-low temperature freezing test chamber. After being frozen at -50°C for 48 hours, an oxygen production test was conducted at -50°C in the ultra-low temperature freezing test chamber. The results showed that the core could not burn completely and the oxygen production rate was only 25%.

[0075] Comparative Example 2

[0076] Weigh 97 g of sodium chlorate, 0.4 g of graphene, 2.5 g of nano-cobaltous oxide, and 0.1 g of lithium peroxide, place them together in a twin-screw mixer, and dry mix them until they are uniformly mixed.

[0077] The mixed raw materials are poured into a custom mold and pressed on a tablet press at 10T / cm 2 The mold was pressed under pressure and dried in an oven at 125°C for 6 hours to obtain a density of 2.0 g / cm3 Oxygen-producing column.

[0078] The oxygen-producing pellets were packaged into a solid oxygen generator and placed in an ultra-low temperature freezing test chamber. After being frozen at -55°C for 48 hours, they were tested at -55°C in the ultra-low temperature freezing test chamber and their performance was monitored using a gas flow detection method. The oxygen production volume flow-time curve was not smooth, indicating incomplete combustion of the oxygen-producing pellets, with an oxygen production rate of 59%.

[0079] The above embodiments represent several specific and detailed implementations of the present invention, but should not be construed as limiting the scope of protection of the present invention. It should be noted that persons of ordinary skill in the art may make various substitutions, modifications, or improvements without departing from the principles and purpose of the present invention, all of which are intended to be within the scope of protection of the present invention.

Claims

1. A catalyst for fuel-free low-temperature oxygen candles, which is a catalyst obtained by adding 10-25wt% of high thermal conductivity carbon-based nanomaterials to a nano-oxide catalyst of iron, cobalt, nickel or manganese as the main catalyst.

2. The catalyst for fuel-free low-temperature oxygen candles according to claim 1, wherein The main catalyst is selected from one of nano-ferroferric oxide, nano-cobaltic oxide, nano-cobaltic oxide, nano-cobaltous oxide, nano-cobaltous oxide, nano-manganese dioxide or nano-nickel oxide, or a combination of several of them.

3. The catalyst for fuel-free low-temperature oxygen candles according to claim 1, wherein The high thermal conductivity carbon-based nanomaterial is any one of graphene, carbon nanotube or nanographite.

4. The method for preparing the catalyst for fuel-free low-temperature oxygen candles according to claim 1 is to mix the main catalyst and the high thermal conductivity carbon-based nanomaterial in the above-mentioned mass ratio, add an appropriate amount of water, ball-mill and mix them uniformly, and then dry and crush to obtain the catalyst.

5. The preparation method according to claim 4, wherein The amount of water added is 10-30% of the mass of the main catalyst.

6. The preparation method according to claim 4, wherein The ball milling mixing is carried out at a rotation speed of 200-500 rpm, and the ball milling time is 0.5-3 h.

7. The preparation method according to claim 4, wherein The drying is carried out at 100-150° C. for 2-5 hours.

8. The preparation method according to claim 4, wherein The catalyst was crushed by nano-grinder to obtain a particle size of less than 500 nm.

9. A fuel-free low-temperature oxygen candle, wherein the catalyst according to any one of claims 1 to 3 is added to the oxygen candle.

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