Method and device for obtaining hydrogen from water

Abstract

FIELD: chemistry.

Description

The invention relates to the field of chemical technology, and more particularly to methods and devices for producing hydrogen by exothermic reaction of water vapor with metals.

A known method and device for producing hydrogen by electrolysis of water, where the electrolyte is an aqueous solution of KOH (350-400 g / l), pressure in electrolyzers from atmospheric to 4 MPa (Chemical Encyclopedia in 5 volumes, edited by N.P. Knunyants. - M .: Sov.Encyclopedia, 1988, vol. 1, p.401).

The performance of electrolytic cells in the known method is 4-500 m 3 / h, and the energy consumption for producing 1 m 3 of hydrogen is 4.0-5.6 kW / h.

The disadvantage of this method is the high power consumption.

A known method of producing hydrogen by the conversion method, which currently receive more than half of industrial hydrogen (Putilova IN Course of General Chemistry. Higher School, 1964, p.208). This method involves the production of water gas (a mixture of CO and H 2 ) from coke and water vapor at a temperature of 1000 ° C (C + H 2 O = CO-H 2 ).

Pure hydrogen is obtained using the reaction of CO and H 2 O in the presence of a catalyst Fe 2 O 3 (CO + H 2 O = CO 2 + H 2 ). The resulting mixture of H 2 , CO 2 and CO is dissolved in water under pressure.

This method, despite the relative cheapness, multi-stage, environmentally harmful and difficult to manage.

A known method and device for producing hydrogen in the chemical reaction of water (H 2 O) and aluminum (Al), resulting in hydrogen (H 2 ) as a fuel and aluminum hydroxide (AlOH) as a raw material suitable for further processing and industrial use :

Al + 3H 2 O = Al (OH) 3 + 1.5H 2 .

Under ordinary conditions, this reaction does not proceed due to the presence on the surface of aluminum of a very thin, but high density oxide film, which forms almost instantly by the reaction:

2Al + 1.5O 2 = Al 2 O 3 .

In the known method and device using an alloy of aluminum and caustic soda, due to which the oxide film around aluminum dissolves, and water is open to the surface of aluminum (patents RF IPC С01В 3/08, No. 2407701, publ. 27.12.2010, No. 2410325, publ. . 01/27/2011). As a solvent in this alloy, an alkali is used, namely caustic soda (NaOH):

2Al + 2NaOH + 10H 2 O = 2Na [Al (OH) 4 (H 2 O) 2 ] + 3H 2 .

The disadvantage of this method and device is the use of a chemically harmful substance - alkali to produce hydrogen.

A known method of producing hydrogen, which consists in supplying metal-containing substances and an aqueous medium to the reactor and subsequent interaction of metal-containing substances with an aqueous medium, in which the metal-containing substances are coated with a water-soluble polymer film before being fed into the reactor, and as the latter when interacting with an aqueous medium use an aqueous medium whose parameters correspond to the parameters of its supercritical state to enable creation Processes layerwise combustion of metal containing substances with evolution of hydrogen. Powdered aluminum is used as metal-containing substances, and a solution of polyethylene oxide in dioxane or methyl alcohol is used as a water-soluble polymer film, and the pressure of the supercritical state of the aqueous medium is more than 22.12 MPa, temperature - more than 647.3 K (Mazalov Yu.A. hydrogen. Patent of the Russian Federation No. 2165888, publ. 04/20/2001).

The disadvantage of this method is the need to use ultrafine aluminum powder with a particle size of 0.2 μm, as well as high pressure and high temperature in the reactor, which increases energy costs and creates safety problems during the process.

The task to which the proposed method and device is directed is to safely produce hydrogen environmentally by a one-step reaction with the possibility of regeneration of the feedstock.

The technical result of the use is to realize direct oxidation of the metal without first heating it, requiring energy consumption and the use of alkali solutions in water.

The above technical result is achieved due to the fact that in the method for producing hydrogen by supplying a metal with an aqueous medium to the reactor according to the invention, the metal is isolated from the walls of the reactor and a high voltage potential of 1-100 kV and a frequency of 1-100 kHz is supplied from the Tesla transformer and with using microplasma discharges in water, the oxide film is removed from the metal surface and the reaction of water metal oxidation is activated.

In a variant of the method for producing hydrogen, aluminum is used as a metal.

In another embodiment of the method for producing hydrogen, magnesium is used as a metal.

In another embodiment of the method for producing hydrogen, an alloy of aluminum with magnesium is used as a metal.

In a device for producing hydrogen from water containing a reactor with a metal with an aqueous medium with pipes for supplying water, removing hydrogen and metal oxidation reaction products, the metal is placed in a container electrically insulated from the walls of the reactor and connected through a bushing with a Tesla high-voltage resonant high-frequency transformer and a source of electrical energy with a voltage at the high voltage terminal of the transformer 1-100 kV and a frequency of 1-100 kHz.

In an embodiment of the device for producing hydrogen from water, plates, cuttings, shavings and sawdust from aluminum, magnesium and aluminum alloys with magnesium are used as metal samples.

A method and apparatus for producing hydrogen from water is illustrated in FIG. 1, which shows a flow diagram for producing hydrogen.

The reactor 1 for producing hydrogen contains a housing 2 with a grounding device 3, a bushing 4 with an electrical outlet 5, which inside the reactor 1 is connected to the container 6 and to the walls 7 of the metal mesh. The container 6 is mounted on insulators 8 inside the reactor 1 and contains a metal 9 of aluminum. The reactor 1 contains a pipe 10 for supplying water, a pipe 11 for the release of hydrogen and a pipe 12 for removing the products of the reaction of aqueous oxidation containing aluminum oxides. The electrical input 5 is connected to the high voltage terminal 13 of the Tesla transformer 14. The low voltage winding 15 of the Tesla transformer 14 together with the capacitor 16 forms a series resonant circuit that is connected to the high-frequency power source 17.

A method and apparatus for producing hydrogen from water is implemented as follows. When the potential is supplied from the high-voltage terminal 13 of the Tesla transformer 14 to the metal 9, plasma high-frequency discharges occur on the surface of the metal 9, which destroy the oxide film on the metal surface, and the water oxidizes the metal with water and produces hydrogen. According to the reaction of aqueous oxidation of aluminum:

2Al + 3H 2 O = Al 2 (OH) 3 + 3H 2 + 921.8 kJ.

The oxidation of 1 kg of aluminum gives 17.1 MJ of heat and 1.4 m 3 of hydrogen, as well as 2 kg of aluminum oxides and hydroxides. When burning the produced hydrogen, the thermal energy increases to 30.57 MJ / kg and exceeds the energy consumption for the regeneration of aluminum from aluminum oxide, which is 26.3 MJ / kg. The reaction rate of aluminum oxidation in water and hydrogen evolution is regulated by a change in potential from a Tesla transformer 14.

In addition to the reaction of water metal oxidation, electrolysis of water occurs, which increases the yield of hydrogen from reactor 1.

An example implementation of the method and device for producing hydrogen from water.

The reactor 1 is a cylindrical stainless steel vessel with a diameter of 200 mm and a height of 400 mm with a wall thickness of 0.6 mm. Inside the reactor vessel 1, a container 6 with aluminum mesh walls is installed on insulators 8. As samples of metal 9 I use plates, cuttings, shavings and sawdust from aluminum. The voltage at the high voltage electrode of the Tesla transformer is 10 kV, the frequency is 25 kHz, the hydrogen output is 1 m 3 / h.

Using the proposed method will reduce energy consumption in the production of hydrogen, increase the controllability and safety of the process, as well as carry out the regeneration of the feedstock. The invention can be used in industry for the production of hydrogen and in transport. When hydrogen is added in an amount of 5% to the fuel, the amount of harmful impurities in the exhaust of the internal combustion engine is reduced by 10 times, engine efficiency is increased and fuel consumption is reduced by 8-10%. The use of hydrogen as 100% fuel in a Stirling engine, gas turbine engine or fuel cell eliminates harmful emissions and ensures the movement of an electric vehicle without recharging batteries up to 500 km.

Claims

1. A method of producing hydrogen by supplying a metal with an aqueous medium to the reactor, characterized in that the metal is isolated from the walls of the reactor and fed to it with a high voltage potential from a Tesla transformer with a voltage of 1-100 kV at a frequency of 1-100 kHz and using microplasma discharges water removes the oxide film from the metal surface and activates the reaction of water metal oxidation.

2. The method of producing hydrogen according to claim 1, characterized in that aluminum is used as the metal.

3. The method of producing hydrogen according to claim 1, characterized in that magnesium is used as a metal.

4. The method of producing hydrogen according to claim 1, characterized in that the metal is an alloy of aluminum with magnesium.

5. A device for producing hydrogen from water, containing a reactor with a metal with an aqueous medium with pipes for supplying water, removing hydrogen and metal oxidation reaction products, characterized in that the metal is placed in a container electrically insulated from the walls of the reactor and connected through a bushing with Tesla high-voltage resonant high-frequency transformer, with a source of electrical energy with a voltage at the high-voltage output of the transformer 1-100 kV and a frequency of 1-100 kHz.

6. The device for producing hydrogen from water according to claim 5, characterized in that the plates, scraps, shavings and sawdust from aluminum, magnesium and aluminum alloys with magnesium are used as metal samples.