The hydrogen absorber based on carbon

 

(57) Abstract:

The invention is intended for use in manufacturing technology material having high sorption activity to hydrogen for storage and transportation. The absorber is made in the form of at least one microreserve body. Microreserve body contains carbon in an amount of more than 90 wt. % and has dimensions in the range of 0.1 µm to 250 mm, and the content of nanopores having a size of 0.8-3 nm, is 20-60 vol.%. Microreserve body may further comprise a transport support size range of 0.05-100 μm in an amount of not more than 50 vol.%. The absorber may contain at least one metal from the group comprising Pd, Pt, Ni, Ti, V, Fe, Co, Nb, Mo, Rh, Ta, W and their alloys. Provides a high sorption capacity of the material with respect to hydrogen. 1 C.p. f-crystals, 1 Il., table 1.

The invention relates to the technology of carbon materials that enables the collection, storage, transportation of hydrogen, in particular, to a technology of material having high sorption activity to hydrogen.

The prospect of exhaustion of hydrocarbon fuel, a large amount of impurities introduced into the surround is the development of technologies using alternative energy. The most promising of them is hydrogen, by oxidation which produces a large amount of energy and does not generate harmful substances. One of the aspects of the use of hydrogen as a fuel is the problem of storage and transportation. For practical use it is necessary that the device that allows you to store and transport hydrogen, were inexpensive, relatively easy, safe and reusable.

Existing variants of the devices and materials storage and transportation of hydrogen have a number of disadvantages. So, when storing hydrogen in a liquid state arises the need for an expensive operation liquefaction, as well as the use of Dewar vessels, with inevitable losses due to boil-off of hydrogen.

The use of hydrogen gas requires compression to high pressure of the order of hundreds of atmospheres, causing the need to use heavy and strong pressure vessels (tanks), which increases the cost of the technology and increases the danger of explosion.

Metal hydrides, such as widespread LaNi5-H6/1/, also the and holding cycles of hydrogenation-dehydrogenation.

The known solution described in the patent /2/ and is the closest solution to the claimed describes the use of layered nanostructures, mainly carbon for hydrogen storage. In a known solution to such structures include the following: carbon filament (fibril), nanotubes (nanotube), nanomachine (nanoshell), nanofibers (nanofiber). In accordance with the patent materials produced by thermal processing of metal powders or carbon materials (e.g. carbon fibers) in the environment of gaseous hydrocarbons in the presence of catalysts. Technology of production of such materials is very complex and allows to obtain only a relatively small amount of the desired substance, the latter cannot be made in the form of product required shapes and sizes. Described in the patent /2/ sorption properties of this material with respect to hydrogen is quite low: for example, for a material with a maximum sorption of hydrogen accumulation at a temperature of 400oC and a pressure of 500 Torr is only 0.0012 atomic fraction.

The present invention is the creation of sink intended for accumulation, storage and transportation vtorostepennuyu ability and the ability to store hydrogen at the level of values, received on metal hydrides.

The technical result is achieved due to the production of an absorber in the form of at least one microreserve body composed of carbon. This microreserve body can be made in the form of products of a given shape, such as blocks or particles. The average size microreserve body is equal to from 0.1 μm to 250 mm Microreserve body has a continuous carbon frame with nanopores containing more than 90 wt.% carbon, and the nanopores, occupying 20-60% of the volume. Microreserve body contains nanopores, which have a size of from 0.8 to 3 nm. In addition, it can be a network of micropores with a size from 0.05 to 100 μm, which is the transport pores for hydrogen advanced close to the Ostia of the nanopore and the components of the amount not exceeding 50% of the volume of the body. The inventive absorber may contain a small amount of catalytically active towards hydrogen metals, such as Ti, V, Fe, Co, Ni, Nb, Mo, Rh, Pd, Ta, W, Pt, etc. Absorber according to the invention may contain at least one metal from the specified group and alloys of these metals.

A method of manufacturing microreserve body with nanopores is that particles of covalent and/or metal-like carbides or preparation of the product, the SFD is the first reaction of chlorine with carbide, the formation of gaseous chlorides carbidopa elements and carbon frame structures, containing nanopores, occupying 20-60% of the volume. When implementing the invention using, for example, silicon carbide, boron carbide, titanium carbide, molybdenum carbide, etc., the size of the nanopores is strictly correlated with the composition of the initial carbide and for covalent and metal-like carbides lies in the range 0.8-3.0 nm. Obtaining materials with volumetric content of the nanopores is outside the specified interval represents a significant challenge. This technology allows to obtain a material with nanoporosity and transport (micropores) pores, the size of which is determined by the conditions of molding. To heat treatment in an environment of chlorine particles or molded of them harvesting the desired size and shape may be subjected to additional heat treatment in the environment of a hydrocarbon or mixtures of hydrocarbons at a temperature exceeding the decomposition temperature of the gaseous hydrocarbons (hydrocarbons).

There is also a variant of the solution that is obtained after heat treatment in an environment of hydrocarbons (hydrocarbons) prefabricated given shape then subjected to impregnation with liquid silicon or metal, which forms a carbide at a temperature exceeding the melting point of silicon or the specified Marinem carbon frame and nanopores size 0.8-3.0 nm. This technology can be implemented, for example, patent RF N 2026735 providing material, having a frame structure, i.e., material that has sufficient mechanical strength and resistance form, but has a large porosity. The open porosity of such material is 35-70% of the volume. To speed up the process of chemisorption of hydrogen microreserve the body after exposure to gaseous chlorine is injected catalytically active towards hydrogen metals, at least one from the group including Ti, V, Fe, Co, Ni, Nb, Mo, Rh, Pd, Ta, W, Pt, etc. and their alloys. The introduction of these metals is possible, for example, with the use of salts of the catalytically active towards hydrogen metals, such as PdCl2, PtCl4and other Introduction is carried out by chemical, electrochemical, and other appropriate methods.

The drawing shows the dependence of the hydrogen concentration from the root of the saturation pressure in the five experimental samples. Samples of N 1 - N 3 made of silicon carbide, followed by processing in natural gas and gaseous chlorine. Received microreserve body have the same dimensions as the workpiece, namely a diameter of 20 mm and a thickness of 1 merode in samples more than 98 wt.%, the volume of the nanopores is 22% of the volume, the size is 0.8 nm (assuming a slotted type long). The size of the transport of long - 0.3-1 μm, and the content in samples and 45% of the volume.

The hydrogen saturation of the samples absorber carried out at a temperature of 600oC technical hydrogen for 2 h in high pressure conditions, namely: sample No. 1 at 250 bar, N 2 - 400 bar, N 3 - 580 bar. To measure the amount of absorbed hydrogen from the samples in the form of tablets cut samples of size HH mm3. Bars carried in the experimental setup, described in /3/, which was a UHV system with a time-of-flight mass spectrometer as a detector of partial pressures of gases. Bars linearly heated at a rate of 10 K/min passing through them with electric current, temperature sensor served as a thermocouple W-WRe attached to the middle of the samples. The hydrogen content was determined by the barometric method. For this purpose, the hydrogen released from the sample as a linear heating, collected in pre-evacuated closed vessel of known volume, in which pressure was measured by strain gauges brand EDC-1, with cuvstvitelnostj barometric data analysis to the weight of the bar.

In the drawing, the measured hydrogen concentration in the samples are presented in the form of a dependence on the square root of the pressure at saturation. Linear dependence for samples N 1 - N 3 indicates a dissociative form of absorption, described in (4).

These data suggest that there is a place of intense absorption of hydrogen by the material until the contents of 2.5-4 at %.

In the samples No. 4 and No. 5, also made of silicon carbide, followed by processing in natural gas and gaseous chlorine, advanced chemical method was introduced palladium. The amount deposited in the pores of the samples of palladium in the processing - 0.5 wt.%. The hydrogen saturation of samples N 4 and N 5 carried out at a pressure of 580 bar in conditions similar to those for samples of N 1 - N 3. Determining the concentration of hydrogen was performed similarly to the method described above. The sample No. 4 was analyzed immediately after saturation with hydrogen, and a sample of N 5 - after exposure to air for 3 months at room temperature. The results are shown in the drawing. As can be seen from the drawing, the sample No. 4, containing palladium, under the same conditions of saturation of absorbed hydrogen in 2.6 times more than the sample No. 3. The comparison sample is oglashenniy hydrogen lossless is stored in the material for a long time. The hydrogen content in the sample No. 4 is 5.11021at/g, which is by weight content comparable with hydride LaNi5-H6- at a concentration of 1 alIU:1 atnthe latter contains 8.31021al/g of hydrogen.

In the same conditions as the samples of N 1 - N 3, were produced additional samples using as a starting material powder of titanium carbide with a particle size of 10-30 μm. Received microreserve body have the volume of nanopores 31%, transport pore size of 3-10 μm. The volume transport of the porosity of 33%. Tablets cut samples of size HH mm3that served as models when saturated with hydrogen. The bars were heated through electric current, temperature sensor served as a thermocouple W-WRe attached to the middle of the samples. Bars carried in the experimental setup described in (3), which was a UHV system with a time-of-flight mass spectrometer as a detector of partial pressures of gases. Before each exposure, the samples were subjected to degassing at a temperature of 1400oC to the cessation of hydrogen evolution. Then set the desired temperature and held the exhibition of the constituent pressure.

After exposure, the sample was cooled to room temperature, the hydrogen from the plant was pumped to a pressure of 10-7Torr. Later in the linear heating rate of 1 K/s was observed the dependence of the emitted stream of hydrogen from the temperature in the temperature range from 40 to 1400oC.

The hydrogen content was determined by the ratio of the integral over time is obtained according to the weight of the samples.

Conditions of saturation of the samples with hydrogen, and the amount of released hydrogen is presented in the table.

The results presented in the table show that the claimed invention allows comparison with the known solution to significantly reduce the pressure of the hydrogen gas when the exposure required to obtain comparable or superior quantity of sorbed hydrogen.

Sources of information:

1. Lundin C. E., Lynch, F. E., Solid State Hydrogen Storage Materials for Application to Energy Needs //.Rept., Afsor, F44620-74-C0020, Denver Res., Inst., Jan. 1975.

2. Patent N 5653951 USA

3. I. E. Gabis, A. A. Kurdyumov, N. A. Tikhonov. Installation for carrying out a comprehensive research on the interaction of gases with metals. The, ISS. 4, 1993. Vol. 2 (N 11), S. 77-79.

4. Ash R. , Agehananda in the form, at least one microreserve body size of 0.1 µm to 250 mm with a continuous frame, the transport pores and nanopores containing carbon in amounts of more than 90 wt.%, it contains nanopores value of 0.8-3 nm in the amount of 20-60% of the volume, and transport pore size of 0.05-100 μm in the amount not exceeding 50% of the volume.

2. The hydrogen absorber based on carbon under item 1, which further comprises at least one metal from the group comprising Pd, Pt, Ni, Ti, V, Fe, Co, Nb, Mo, Rh, Ta, W and their alloys.

 

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FIELD: production of charcoal-fibrous adsorbents.

SUBSTANCE: the invention is dealt with the field of production of charcoal-fibrous adsorbents, in particular, with devices of charcoal-fibrous materials activation. The installation contains a vertical furnace for activation of a carbon fabric and a conjugated with it steam generator, which are connected to the power source and a control unit. And at the furnace output there is a reception device. At that the furnace contains a through heated muffle, through which the treated charcoal-fibrous fabric is continuously passing. At that the muffle is located inside the detachable heat-insulating furnace body, on the inner side of which there are heating elements. Besides at the furnace outlet there is a movable container with water, in which the lower end of the through muffle is dipped. The invention offers an installation for production of activated charcoal-fibrous material, which ensures a continuous process of treatment of the charcoal-fibrous material with an overheated steam and formation of the activated fabric with high mechanical properties and a cellular structure, simple in assembly and reliable in operation.

EFFECT: the invention ensures production of the activated fabric with high mechanical properties and a cellular structure, simple in assembly and reliable in operation.

8 cl, 4 dwg

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