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INVENTION
Russian Federation Patent RU2048435

HOW LONG hydrogen storage

HOW LONG hydrogen storage

Name of the inventor: Borisevich Yuri Pavlovich
The name of the patentee: Borisevich Yuri Pavlovich
Address for correspondence:
Starting date of the patent: 1992.03.16

The invention relates to methods for gas storage and can be used in the chemical, petrochemical and refining industries. The proposed method is carried out by partial resurfacing = Al 2 O 3 molecular activated with hydrogen or a hydrogen-containing gas at a temperature of from 100 to 750 ° C, a pressure of from 1.0 to 10 atm, and gas humidity from 10 -5 to 10 -1 vol.%, Followed by oxidation of the surface of the partially reduced = Al 2 O 3, water vapor at a temperature of from 100 to 750 ° C in an inert gas at atmospheric pressure or vacuum, with humidity from 10 -2 to 10 -5 vol.%, After storage, implemented partially reduced oxide in air humidity arbitrary at temperatures up to 50 ° C, in vacuum or inert gas atmosphere at an arbitrary temperature and humidity -5 to 10 vol.%.

DESCRIPTION OF THE INVENTION

The invention relates to methods for gas storage and can be used in the chemical, petrochemical and refining industries.

There are ways hpaneniya gases compressed, liquefied absorbed and adsorbed state, and in the crystalline hydrate form.

The disadvantages of these methods in relation to hydrogen are great technical difficulties and high costs in the liquefaction of hydrogen due to its extremely low boiling temperature, high storage losses due to the same reason, increased fire and explosion hazards of liquid hydrogen, but also the need for liquefaction or pure hydrogen or special devices to separate it from the gases, condensable at higher temperatures, hydrogen compression and fairly complicated and expensive process that although minimizes losses during storage, but does not reduce fire and explosion, which adds considerable complexity in operation vessels operating under significant pressure and are characterized by a high metal content, in addition, the receipt and storage of compressed hydrogen requires its original purity; storage of hydrogen adsorbed and adsorbed state of the technique is not widely applied (possibly except where it dissolves in the Pd), because it is characterized by low retention capacity of all known adsorbents and absorbents, many of which are rare and precious substances (for example, noble metals), often incomplete reversibility with the desorption and the impossibility of long-term storage of hydrogen in this state as a consequence of technical inconveniences and due to oxidation by atmospheric oxygen; Storage of hydrogen in the crystalline hydrate form of industrial importance (unlike petroleum gas) and has not, for receiving and storing such substances are required and hard to reach trudnopodderzhivaemye conditions associated with high costs.

The closest the technical essence and achieved the effect of the proposed method is the partial resurfacing -Al 2 O 3 with hydrogen, followed by oxidation of the surface of the reduced water vapor. The disadvantages of this method are a partial restoration of the surface -Al 2 O 3 only in the hydrogen flow, and only at atmospheric pressure, whereby the total amount of hydrogen "pledged deposited" much smaller quantities of hydrogen, to restore the surface expended and therefore the amount of hydrogen "received from storage" is much less than the amount of hydrogen expended the restoration of the surface conditions of long-term storage of hydrogen in this state in the present analogue in general have not been studied.

The invention aims to increase safety during prolonged storage of hydrogen and reduced storage costs.

This goal is achieved by the method described partial resurfacing -Al 2 O 3 in a closed volume molecular, active hydrogen-containing hydrogen or hydrocarbon gas to freeze water formed at a temperature of 100 to 750 ° C, a pressure of from 1 to 10 atm, and gas humidity from 10 -5 to about 10 -1. ( "Hydrogen tab on storage"), followed by oxidation of the surface of the partially reduced -Al 2 O 3, water vapor ( "acquisition of hydrogen storage") at temperatures from 100 to 750 ° C in an inert gas at atmospheric pressure or vacuum with a humidity of 10 -5 to about 10 -2. undertaken after prolonged storage of partially reduced oxide (specific surface area of from 200 to 400 m 2 / g) in an air environment arbitrary humidity at temperatures up to 50 ° C, a vacuum or in an inert gas atmosphere at an arbitrary temperature (750 ° C) and humidity about 10 -5.

Essential difference of the proposed method from the known consists in that the first partial recovery of the solid surface with hydrogen or a hydrogen-containing gas in the absence of adsorption is proposed as "hydrogen storage" extracted in strict accordance with the "laid capacity" by the oxidation of water vapor previously partially reduced surface -Al 2 O 3.

The novelty of the proposed technical solutions lies in the fact that as a long-term storage of hydrogen used in the partially closed volume reconstituted freeze-released water -Al 2 O 3, which can be stored in air, inert gas or vacuum, without losing the ability to release hydrogen in strict accordance with the amount laid down in the oxidation of the surface of the previously partially restored -Al 2 O 3, with water vapor.

It is known that according to the law of electrostatic valence [Pauling L. The Nature of the Chemical Bond, 3 rd ed. Cornell Univ. Press. Jthaca, New York, 1960, p.548] working in a stable ionic charge structure should be equal or approximately equal to zero. Since this requirement is best satisfied OH groups instead of oxygen, the anion layer, which, according to the principles of energy, should limit the surface of the crystallite -Al 2 O 3 layer is preferably hydroxyl.

It is known that molecular hydrogen and activated at a temperature of 100 to 750 C and the gas humidity from 10 -5 to about 10 -1. under flow conditions it is able to partially restore the surface -Al 2 O 3 [YP Borisevich Interaction of hydrogen with the surface -Al 2 O 3, and its role in the processes of dehydrogenation and dehydrocyclization. Abstract of dissertation for the degree of Cand. Chem. Sciences, Minsk 1985 Byelorussian Academy of Sciences, and so on-Physical-Organic Chemistry] Since the reaction of hydrogen with the surface -Al 2 O 3 followed by dehydroxylation extension surface compared with calcination in a vacuum or inert gas in the same temperature range of the resulting surface defects are fundamentally different from surface defects obtained by dehydroxylation -Al 2 O 3 in a vacuum or an inert gas, which determines the ability of the oxide considered to act as a "repository" of hydrogen. dehydroxylation -Al 2 O 3 in an inert atmosphere or in a vacuum, flowing through the mechanism proposed by [Peri JB A Model for the Surface of -Alumina. J.Phys. Chem. 1965, v.69, N 1, p.220-231] is accompanied by the formation of a surface layer of oxygen anions, while at dehydroxylation -Al 2 O 3 in the hydrogen medium surface hydroxyl groups are removed significantly better (as H 2 O), whereby the exposed aluminum layer of positively charged ions, which allows to consider the interaction of the alumina with hydrogen as the surface recovery. For every degree of temperature recovery removal of OH groups is determined by the system humidity. Reducing the moisture content of the system (freezing of H 2 O) shifts the equilibrium toward the stable existence of the reconstructed surface. The quantity of hydrogen is thus potentially "laid on storage", increases. Increased moisture shifts the equilibrium toward the surface hydration. The quantity of hydrogen is thus potentially "laid on storage" decreases. Thus, there is moisture limit above which make it impossible for the recovery of each recovery point. With the increase in the recovery temperature, the amount of hydrogen that is potentially "laid on the storage" is increased up to the maximum possible for the system and the specific humidity of the sample surface -Al 2 O 3. With the increase in specific surface area alumina "storage capacity" naturally increases (including the sample and at crushing) until surface browning during recovery. With an increase in the hydrogen pressure in the reduction of "storage tank" and increases, and the maximum capacity at the same values ​​of the system and the specific surface moisture can be achieved at lower temperatures, due to greater ease removal of OH groups with increasing hydrogen pressure.

The use of activated hydrogen to restore (or activation may be performed using high-frequency discharge, using either or Jumpover spillover phenomenon in the case of platinum black or platinum catalyst, or finally by irradiation) further facilitates the process of resurfacing -Al 2 O 3 due to the much higher reactivity of activated hydrogen as compared to the molecular, which allows to achieve a single "storage capacity" in the same system humidity values, surface area and oxide pressure at much lower temperatures.

Finally, restore the surface -Al 2 O 3 is possible, and a hydrogen-hydrocarbon gas (in the absence of oxygen in it, in these conditions is able to cause reverse surface oxidation). The degree resurfacing -Al 2 O 3, ceteris paribus is determined by the partial pressure of free hydrogen, and heavier hydrocarbons can cause a partial carbonization surface -Al 2 O 3, which somewhat reduces the "storage capacity".

Of course, to shift the balance okislenievos formation surface -Al 2 O 3, carried out in a closed volume (to conserve hydrogen) in the direction of restoring the surface during "tab on hydrogen storage" is required freezing the resulting moisture, which is easiest to implement on zeolites (such as NaX), cooled to liquid nitrogen temperature. In that case the hydrogen consumption in the reduction of surface -Al 2 O 3 is not a limiting factor, the process can be performed at flow without freezing the resulting moisture. The upper temperature limit resurfacing -Al 2 O 3 (750 ° C) is limited by sintering -Al 2 O 3, so that the specific surface of the oxide (and hence the "storage capacity") begin to decline sharply. The lower temperature limit resurfacing -Al 2 O 3 (100 ° C) limited the reaction of hydrogen with respect to the ability of aluminum oxide. The lower limit of the gas humidity in the reduction of -Al 2 O 3 (10 -5 vol.) Is limited only by technical difficulties deeper gas dehydration. The upper limit of the humidity of the gas in the reduction of -Al 2 O 3 is limited by the equilibrium shift oxidation restoring the surface to the far left position, in which no surface reconstruction is impossible even at the highest temperatures of the claimed range. The lower limit of the hydrogen pressure (partial pressure of hydrogen or in the case of hydrogen-hydrocarbon gas) is limited to a minimum of 1 atm "storage capacity" in which the method is more appropriate with a further pressure reduction potential -Al 2 O 3 are almost entirely unrealized. The upper limit of the hydrogen pressure (10 bar) is limited to technical difficulties on compressed hydrogen, and most importantly, the restoration of the surface is too deep -Al 2 O 3, wherein the water vapor oxidation future becomes difficult in the patented temperature range.

After resurfacing -Al 2 O 3 ( "hydrogen tab on storage"), and cooling to room temperature in a recovery oxide is ready for lengthy storage of hydrogen or air humidity at an arbitrary temperature to 50 ° C, either in a vacuum or in an inert gas environment at arbitrary temperature and humidity to about 10 -5.

The upper temperature limit (50 ° C) for storage of the reduced oxide in the air due to the inability of water vapor concentration of any cause significant oxidation of the reduced surface -Al 2 O 3 (with evolution of hydrogen) to the specified temperature due to their lack of reactivity.

The upper limit humidity (about 10 -5.) Under vacuum or in inert gas storage reduced oxide at an arbitrary temperature (750 ° C) caused by the inability of water vapor (because of their insignificant concentration) cause significant surface oxidation prereduced (evolution of hydrogen) until the beginning of sintering the oxide surface.

Production of hydrogen storage due to the oxidation of water vapor prereduced surface -Al 2 O 3, with a fully restored original hydroxyl cover solid. The amount of hydrogen "received from storage" determined by the depth surface oxidation prereduced -Al 2 O 3, which is proportional to the temperature and humidity in the oxidation. Moreover, for each degree of recovery -Al 2 O 3, there is a humidity threshold below which oxidation becomes impossible and limit equal to about 10 -5. above that for any degree of reduction in the range of oxidation temperatures of 100-750 C may be obtained by all hydrogen, "previously deposited inherent". Lower Temperature Limit for the oxidation of pre-reduced oxide surface -Al 2 O 3 (100 ° C) due to the fact that at lower temperatures, even at very high humidities system oxide oxidation may be complete, i.e. the amount of hydrogen "retrieved from storage" will be significantly less than the amount of hydrogen "pledged for storage." The upper temperature limit during the oxidation of the surface oxide prereduced -Al 2 O 3 (750 ° C) due to the heat-resistant surface -Al 2 O 3 sintering, ie. E. At higher temperatures, a decrease of the specific surface -Al 2 O 3, and thus reduced "storage capacity" for re "tab on hydrogen storage."

The lower limit of the system of moisture in the oxidation of pre-reduced oxide surface -Al 2 O 3 (about 10 -5.) Is due to the reactivity of water vapor that at lower concentrations are not capable of fully oxidized surface -Al 2 O 3, even at very high temperatures (750 ° C), i.e. the amount of hydrogen "retrieved from storage," is less than the amount of hydrogen that is embedded in storage.

The upper limit of the humidity in the oxidation system prereduced oxide surface -Al 2 O 3 (about 10 -2.) Is due to the reactivity of water vapor, which is already at a given concentration able to completely remove the hydrogen from the storage even at heating temperatures not to limit, so a further increase in humidity simply impractical.

These difficulties associated with the storage of hydrogen by conventional methods can be overcome if long-term storage for the oxidation process use restoration -Al 2 O 3.

This technical solution provided in the present process.

Example 1. Hinge (50 g) -Al 2 O 3 (0.2-0.5 mm) having a specific surface area of 200 m 2 / g in a confined space was partially restored by molecular hydrogen (formed by absorption with water clinoptilolite cooled by liquid nitrogen) under temperature programmed heating at 40 ° C / min to a temperature of 750 ° C and held at 750 for about an hour, a pressure of 1 atm and a gas humidity of 10 -5. Upon exposure of the sample -Al 2 O 3 at 750 ° C for one hour, the hydrogen pressure and humidity are maintained at the initial level. After cooling in the recovery environment to room temperature and a long two-month storage in a partially reduced oxide arbitrary air humidity (room conditions) at a temperature of 50 ° C, the oxide was treated with water vapor in a helium environment (humidity of 10 -2.) At atmospheric pressure and temperature programmed (40 ° C / min), heating to a temperature of 750 ° C. After 750 hours at ° C was obtained from the store 4 liters H 2 / 1L -Al 2 O 3.

Example 2. Unlike Example 1, a partial recovery -Al 2 O 3 was carried out at 10 atm. From the vault it was obtained 10 l of H 2/1 liter -Al 2 O 3.

Example 3. Unlike Example 1, a partial recovery -Al 2 O 3 was carried out at 5 atm. From the vault was obtained 7 l H 2/1 liter -Al 2 O 3.

Example 4. Unlike Example 1 was used for the partial recovery of the surface -Al 2 O 3 with a specific surface area of 400 m 2 / g. Was obtained from the repository 8 liters H 2 / 1L -Al 2 O 3.

Example 5. Unlike Example 1 the partial resurfacing was used -Al 2 O 3 with a specific surface area of 300 m 2 / g. Because storage has been received 6 liters of H 2/1 liter -Al 2 O 3.

Example 6. Unlike Example 1, a partial restoration surface -Al 2 O 3 was carried out at a humidity of about 10 -1 system. From the vault was obtained 0.34 liters H 2/1 liter -Al 2 O 3.

Example 7. Unlike Example 1, a partial restoration surface -Al 2 O 3 system was carried out at about 10 -3 humidity. From storage was obtained 1.5 liters of H 2 / 1L -Al 2 O 3.

Example 8. Unlike Example 1, a partial restoration surface -Al 2 O 3 was carried out at 600 ° C was obtained from storage 0.2 liters H 2/1 liter -Al 2 O 3.

Example 9. Unlike Example 1, a partial restoration surface -Al 2 O 3 was carried out with hydrogen, activated a platinum catalyst at 100 ° C was obtained from the repository 1 liter H 2/1 liter -Al 2 O 3.

Example 10. Unlike Example 9, a partial restoration of the surface -Al 2 O 3 was carried out at 750 ° C was obtained from storage 12 liters of H 2/1 liter -Al 2 O 3.

Example 11. Unlike Example 1, a partial restoration surface -Al 2 O 3 was performed with a hydrogen-hydrocarbon gas (85 vol. H 2 and 15 vol. CH 4). From the vault was obtained 3.75 liters H 2/1 liter -Al 2 O 3.

Example 12. In contrast to Example 1 kept recovered alumina 1.5 years. From the vault was obtained 3.95 liters H 2/1 liter -Al 2 O 3.

Example 13. Unlike Example 1 the recovered alumina was stored in vacuo (0.1 mm Hg, P). From the vault was obtained 4.1 liters H 2/1 liter -Al 2 O 3.

Example 14. Unlike Example 1, the alumina recovered helium stored in an arbitrary medium (750 ° C) temperature and humidity of the system to about 10 -5. From the vault was obtained 4.1 liters H 2/1 liter -Al 2 O 3.

Example 15. Unlike Example 1, the production of hydrogen from the storage system was carried out at about 10 -5 humidity. From the vault was obtained 0.22 liters H 2/1 liter -Al 2 O 3.

Example 16. Unlike Example 1, the production of hydrogen from the storage system was carried out under humidity of 10 -3.5. From storage 1.3L H 2/1 l was obtained -Al 2 O 3.

Example 17. Unlike Example 1, the production of hydrogen from storage was carried out under temperature programmed heating to 100 ° C and holding at 100 ° C for 1 hour. From the storage was obtained 0.15 liters of H 2 / 1L -Al 2 O 3.

Example 18. Unlike Example 1, the production of hydrogen from storage was carried out under temperature programmed heating to 400 C. From the "storage" was obtained 1.85 liters of H 2 / 1L -Al 2 O 3.

Example 19. Unlike Example 1, the production of hydrogen from storage was performed in vacuum at the same humidity system. Because storage has been received 4 liters of H 2/1 liter -Al 2 O 3.

These examples 1-19 the data produced by the laboratory study of redox processes of real samples -Al 2 O 3.

CLAIM

HOW LONG hydrogen storage, which includes a partial restoration of the surface - Al 2 O 3 the oxidation of hydrogen and water vapor recovered surface, characterized in that the oxide is subjected to rehabilitation - Al 2 O 3 having a specific surface area of 200 400 m 2 / g, which is carried out with molecular hydrogen or a hydrogen-hydrocarbon gas at 100 750 o C to freeze the water generated, a pressure of 1 atm and 10 gas humidity of 10 -5 - 10 -1 vol. long-term storage is then carried partially reduced oxide in air humidity at an arbitrary temperature to 50 o C in a vacuum or in an inert gas environment at a temperature 750 o C and humidity up to about 10 -5. and subsequent oxidation of the partially reduced surface - Al 2 O 3 is carried out with water vapor at 100 750 o C in an inert gas atmosphere under atmospheric pressure or in a vacuum of 10 -5 humidity of 10 -2.

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Publication date 26.02.2007gg