RU2292406C2 - Hydrogen generation and transportation process - Google Patents

Abstract

FIELD: hydrogen production processes.

SUBSTANCE: generation of hydrogen, designed for use as energy carrier being fuel additive and as consumer-destined pure hydrogen source, is accomplished by electrolysis of aqueous solution using cathode with its one end in aqueous solution and the other in possession of consumer. Pressure at the cathode end in consumer's possession is below and temperature higher than the same at the end in aqueous solution. Cathode is made from materials such as Ta, Pd, Pt, Ni, Mg, Ti, V, Nb, U, Mg₂Ni, TiFe, LaNi₅, alloys V-Nb, Ni-Ta, which incorporate hydrogen in their frameworks.

EFFECT: reduced hydrogen transportation losses, increased its purity, and decreased number of operations from hydrogen source to hydrogen consumer.

1 dwg

Description

The invention relates to the field of production and transportation of pure hydrogen, which can be used as an energy carrier for fuel additives and as a source of pure hydrogen to the consumer.

Known methods for producing hydrogen [Abstracts of the IV International Conference "Sustainable Development of Mountain Territories: Problems of Regional Cooperation and Regional Mountain Policy". Volume 1, Vladikavkaz, 2001, p.186-188] by steam reforming of hydrocarbon compounds, thermochemical decomposition of water, followed by transportation of hydrogen through pipelines or in steel cylinders.

The disadvantage of this method is the use of expensive equipment and materials.

The closest technical solution is a method for producing hydrogen, including the electrolysis of water or an aqueous solution [US 4146446, 25V 1/04, 03/27/29], in which materials that absorb hydrogen are used as the cathode, and oxidized materials are used as the anode in the electrochemical process of oxygen evolution. In this case, bound hydrogen is again released during heat treatment of the cathode and accumulates in the hydrogen receiver. Similarly, bound oxygen is released from the corresponding oxides during heat treatment and accumulates in the oxygen receiver.

The disadvantage of this method is that during the electrolysis periodically, heat treatment of the cathode and anode material is necessary after they are saturated with electrolysis products, followed by the use of the released hydrogen and oxygen for its intended purpose.

The objective of the invention is to provide an effective method for the continuous production, transportation and use of hydrogen.

The technical result that can be achieved by carrying out the invention consists in a more efficient use of hydrogen: its losses during transportation are reduced, since there are no intermediate capacities for collecting hydrogen, the purity of hydrogen is increased, and the number of operations from the source of production to the place of hydrogen consumption is reduced.

This technical result is achieved in that the method for producing and transporting hydrogen involves electrolysis of an aqueous solution using a cathode, one end of which is in the aqueous solution, and the other end is in the consumer, the pressure at the end of the cathode located in the consumer is lower, and the temperature is higher than at the other end of the cathode in aqueous solution, the cathode being made of materials such as Ta, Pd, Pt, Ni, Mg, Ti, V, Nb, U, Mg ₂ Ni, TiFe, LaNi ₅ , V-Nb, Ni alloys -Ta and other materials that incorporate hydrogen into the lattice.

The essence of the method lies in the fact that the transport of hydrogen was carried out directly to the consumer, where the hydrogen produced at the cathode during the electrolysis is released by diffusion of hydrogen over the cathode material due, for example, to a temperature difference (a higher temperature for the hydrogen consumer compared to the temperature in the electrolyzer) or due to the pressure drop (lower pressure at the hydrogen consumer compared to the pressure in the electrolyzer), as well as by diffusion into the material with higher abilities absorb hydrogen. Similarly, the oxygen released on the inert anode can be delivered to the oxygen consumer.

For example, the whole process using the dependence of the solubility of hydrogen in the cathode material on temperature can be divided into the following stages:

I. In the electrochemical system

1. Electrolytic dissociation:

Cathodic reaction

2Н ₂ O + 2хМе + 2е → 2ОН ^- + 2Ме _x Н

Anode reaction

2OH ^- → H ₂ O + ^l / ₂ O ₂ + 2e

Total reaction

H ₂ O → 2Me + 2hMe _x N + _^1/2 O ₂

II. At the consumer:

Thermal Dissociation:

2Me _x H → 2xMe + H ₂ .

To increase the conductivity of water, electrolytes can be added to it: alkalis, acids, salts, etc. Then the total reaction during electrolysis can be expressed, for example, by the equations

2HCl → H ₂ + Cl ₂

2H ₂ O + 2NaCl → H ₂ + 2NaOH + Cl ₂ .

Such reactions can serve not only to produce hydrogen, but also to produce chlorine.

As the cathode material, one can use Ta, Pd, Pt, Ni, Mg, Ti, V, Nb, U, Mg ₂ Ni, TiFe, LaNi ₅ alloys V-Nb, Ni-Ta, etc., i.e. materials that introduce hydrogen into the lattice and emit it during heat treatment.

As the anode material, silver, stainless steel, mercury, manganese oxide Mn ₂ O ₃ , etc. can be used. Oxides, chlorides, etc. can be formed during the electrolysis, which can also produce oxygen, halogens, etc. during subsequent heat treatment.

Thus, in the heat treatment process, the cathode and anode are regenerated and reused in the electrochemical process.

For maximum absorption of hydrogen, oxygen or halogen, it is better to use materials with a well-developed surface.

When used as a cathode, for example, palladium is known [Properties of elements .- Handbook, ed. M.E. Dritza - v.2. - M .: Metallurgy, State Unitary Enterprise “Non-Ferrous Metals Magazine”, 1997. - P.225-226], that it intensively absorbs hydrogen (up to 800 volumes at 20 ° С), which is associated with its high catalytic activity. With increasing temperature, the solubility of hydrogen in palladium decreases rapidly, and its diffusion rate increases. The diffusion parameters of hydrogen in palladium at temperatures of 196-998 K:

frequency factor D = 2.9 · 10 ^-7 ,

activation energy E = 22.2 kJ / mol,

the initial heat of hydrogen adsorption on palladium Q ₀ = 124 kJ / mol.

и β(PdH_0,59).It is generally accepted that palladium forms two non-stoichiometric phases with hydrogen:

and β (PdH _0.59 ).

The normal electrode potential of the reaction Pd-2e → Pd ²⁺ is φ ₀ = 0.987 V, its redox potential in acidic media is 0.64-0.83 V, the electrochemical equivalent of palladium Pd ²⁺ is 0.553 mg / C.

According to the authors [R. Ripan, I. Chityanu. Inorganic chemistry. - Part 2.- M: Mir, 1972. - p.653], colloidal palladium, then powdery and, finally, spongy palladium, has the greatest absorption capacity with respect to hydrogen. At room temperature, one volume of palladium metal absorbs 2800 volumes of hydrogen and the absorption capacity increases when silver, gold or boron is added to metal palladium. Palladium can give off hydrogen in vacuum when heated to 300 °. Hydrogen absorption by palladium is accompanied by the formation of a solid solution or the formation of inclusion hydrides Pd ₂ H, PdH _0.6 .

According to the authors [Kurdyumov A.V. and others. Production of castings from non-ferrous metal alloys. M .: Metallurgy. - 1986. - c.332-333] the equilibrium solubility of hydrogen in palladium is described by the equation

At the melting point, palladium dissolves up to 60 cm ^{3 of} hydrogen in 100 g of palladium, at room temperature - 850 volumes of hydrogen.

Thus, when hydrogen is produced electrochemically from water or an aqueous solution, when the cathode is palladium, which is released as a result of the electrochemical process at the cathode, hydrogen will be absorbed by palladium, then palladium will transport hydrogen to its place of use, for which the other end of palladium can be made in the form of a sponge with a well-developed surface.

To transfer hydrogen from the cathode to the consumer, one can use the dependence of the solubility and diffusion of hydrogen in palladium on temperature and pressure:

- the end of the cathode facing the consumer has a higher temperature than the other end of the cathode located in the hydrogen source;

- at the end of the cathode facing the consumer, the pressure is lower than at the other end of the cathode located in the hydrogen source.

To transfer hydrogen, you can use a bimetallic plate of materials with different solubilities of hydrogen, and the material of the plate with less solubility is in the cell, and with greater solubility in the consumer, the transfer of hydrogen is carried out by diffusion at the contact points of the materials of the bimetallic plate with different solubility of hydrogen.

It is known that hydrogen in a metal is in an atomic state, which creates additional prerequisites for using atomic hydrogen as active centers of various chain processes. If titanium, steel and other inert materials are used as the anode, then the oxygen released at the anode can be practically used, and if released into the atmosphere, it improves the ecology of the environment.

An example of practical application.

The drawing shows the installation (electrochemical generator (ECG) of hydrogen production and transportation), operating on the principle of a continuous process: 1 - housing, 2 - cathode, 3 - anode, 4 - aqueous electrolyte solution.

With regard to the operation of the internal combustion engine (ICE), the power source at the initial moment is the battery (AB).

The battery in the car also serves to supply electric power to the starter when starting the engine and the backup engine power supply system with gasoline for short-term operation of the engine in order to heat the end of the cathode and supply hydrogen released from the cathode when heating the engine.

If the power consumed by the switched on consumers exceeds the power developed by the generator, the battery, when discharged, provides power to consumers simultaneously with the operating generator.

The current in the bath is regulated and controlled from the cab of a truck or a car body. With an increase in the engine’s revolutions, the generator generates more electricity (voltage and electric current increase in the bath), which accordingly intensifies the release of hydrogen at the cathode, accelerates and increases the amount of hydrogen absorbed by the cathode.

Starting and heating the engine, and therefore the cathode, is carried out on gasoline with the subsequent transition to hydrogen. The engine is stopped by turning off the ignition, while the electrolysis in the bath stops.

Hydrogen can also be supplied to hydrocarbon fuel in the internal combustion engine to increase its reactivity, power and fuel economy, as well as to reduce the toxicity of exhaust gases.

To increase the power of the ECG installation, it is possible to make it in the form of a multi-chamber electrolyzer; you can also supply the required number of generators and batteries.

The electrochemical generator operates as follows. The aqueous solution is poured into the ECG, the battery is connected to the poles (minus to the cathode 2, plus to the anode 3 in accordance with the drawing). In the ECG, increased pressure and cooling are created, after which the electrolysis process is carried out. At the consumer, atmospheric pressure and heating produce hydrogen in accordance with equation (1). Hydrogen released from the consumer is recorded using conventional analytical tools, which confirms the possibility of transporting hydrogen. Higher results were obtained when pumping hydrogen from the consumer.

A method of producing and transporting hydrogen can be used:

- for the delivery of hydrogen as fuel to the engine mixer,

- for the addition of hydrogen to fuel in the internal combustion engine,

- in reactions involving hydrogen, especially if the cathode is used as a catalyst,

- for the delivery of ultrapure hydrogen when filling containers.

Compared with the prototype, the proposed method for producing and transporting hydrogen intensifies processes in which hydrogen is used, reduces hydrogen losses during transportation, maintains high purity of hydrogen, reduces the number of operations from the source of production to the hydrogen consumer, and there is no need to use intermediate hydrogen collectors.

Claims (1)

A method for producing and transporting hydrogen, including electrolysis of an aqueous solution using a cathode, one end of which is in the aqueous solution and the other end is in the consumer, while the pressure at the end of the cathode located at the consumer is lower and the temperature is higher than at the other end of the cathode, located in an aqueous solution, the cathode being made of materials such as Ta, Pd, Pt, Ni, Mg, Ti, V, Nb, U, Mg ₂ Ni, TiFe, LaNi ₅ , V-Nb, Ni-Ta alloys and others materials that incorporate hydrogen into the lattice.