RU2266157C1 - Hydrogen generator - Google Patents

Abstract

FIELD: power equipment; generation of hydrogen both in stationary plants and in transport facilities.

SUBSTANCE: proposed hydrogen generator is made in form of chemical reactor generating hydrogen by hydrolysis, i.e. by decomposition of water by use of solid reagent and hydrolysis reaction of heterogeneous nature proceeding on solid agent surface. Hydrogen thus generated shall be used in power plants working on fuel elements. Hydrogen may be also used for cutting and welding of metals. Hydrogen generator working on hydrolysis exothermic reaction includes reaction vessel with hydrogen supply main and heat exchanger for removal of reaction heat. Generator is also provided with two hydrogen accumulators fitted with pressure sensors; each hydrogen accumulator is pneumatically connected with reaction vessel through inlet valve and with hydrogen supply main through outlet valve; hydrogen accumulators are made in form of hermetic reservoirs partially filled with water and hydraulically interconnected through heat exchanger used for removal of reaction heat and water flow regulator connected with pressure sensors fitted in hydrogen accumulators. Provision is made for autonomous operation of generator which may be cooled in automatic mode.

EFFECT: enhanced operational reliability at simple control algorithms.

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Description

The invention relates to power equipment and can be used to produce hydrogen both in stationary installations and in transport.

The generator is a chemical reactor that produces hydrogen by hydrolysis, i.e. decomposition of water. For this, a solid reagent is used, i.e. the hydrolysis reaction is heterogeneous in nature - occurs on the surface of a solid. It is assumed that the hydrogen thus obtained is subsequently used as fuel for power plants (EC) on fuel cells (FC). In addition, hydrogen can be used, of course, in other areas, for example, in metal cutting, welding, etc.

The most famous example of a gas generator with a solid reagent are acetylene generators of the types GNV-1.25 and GVR-1.25 and others [1]. They also use a heterogeneous hydrolysis reaction, and calcium carbide serves as a solid reagent. A hydrogen generator that works using the hydrolysis of aluminum in an aqueous solution of alkali [2] (analogue) works in a similar way. In this case, however, hydrogen is continuously generated, and the entire system, including the generator, operates according to a flow-through scheme. The disadvantages of the analogue include the following:

- the use of a "flow" circuit complicates the design of the generator and requires additional energy consumption, which reduces the overall efficiency of the installation;

- the operation of the reactor is ensured by a special external cooling system, which reduces the reliability of the reactor, increases the energy consumption of the system into which it enters, and complicates the autonomous operation of the generator.

Closer to the intended solution is a hydrogen generator of a power plant (EU) underwater for fuel cells [2] (prototype). The efficiency of the EU in this case is higher, since the circulation circuit is not used here. However, the prototype also has significant disadvantages, which include the following:

- an expensive solid reagent (LiH) is used;

- for cooling the generator, an “external” cooling system is used, which reduces the efficiency installation and its reliability;

- in addition, the external cooling system of the hydrogen generator narrows the possibilities of its autonomous use and complicates the design.

The objective of the proposed solution is to develop an autonomous hydrogen generator that works without an “external” cooling system and does not require (for its cooling) energy consumption.

The problem is solved in that two hydrogen accumulators are introduced into a hydrogen generator operating on an exothermic hydrolysis reaction and containing a reaction vessel with a hydrogen delivery line and a heat exchanger for removing reaction heat, characterized in that two hydrogen accumulators equipped with pressure sensors are introduced into the generator composition each hydrogen accumulator is pneumatically connected through an inlet valve to the reaction vessel, and through its outlet valve, to a hydrogen delivery line, and the hydrogen accumulators are made in de sealed containers, partially filled with water and hydraulically connected to each other through a heat exchanger to remove heat of reaction and the water flow regulator, which, together with the valves electrically connected with the control unit to which is also connected the pressure sensors installed in the hydrogen storage medium.

The essence of the proposal is that the generated hydrogen is collected alternately in one of two hydrogen storage tanks (tanks) in which water is located and which are hydraulically connected to each other. In this case, the pressure of hydrogen, water is alternately displaced from one tank to another. During the overflow process, this water is passed through a heat exchanger to remove the heat of reaction and it cools the reactants. Thus, in the process of operation, the hydrogen generator “cools itself” without using special systems with pumps, electric motors, etc., that is, the mechanical energy of the generated hydrogen is directly used, while the flow of cooling water is regulated. This helps to increase the efficiency of power plants with such a generator, increases their reliability and turns the hydrogen generator into an autonomous mechanical device.

In addition, such a scheme is characterized by auto-regulation of the cooling intensity: the faster hydrogen is released and its pressure in the receiver is higher, the higher the flow rate of cooling water through the generator (as you know, the flow rate is proportional to the displacement pressure). Thus, the increase in heat generation in the generator (proportional to hydrogen evolution) automatically increases the heat transfer from the generator, and this cooling system works without heat sensors.

The proposed generator has, in addition, a simple design and has an elementary control algorithm.

The diagram of the proposed generator design is shown in the drawing, where it is indicated:

1 - reaction vessel;

2 - a line for the delivery of hydrogen;

3 - heat exchanger for removing heat of reaction;

4 - hydrogen storage;

5 - inlet valves of hydrogen storage;

6 - output valves of hydrogen storage;

7 - pressure sensors;

8 - heat exchangers, coolers;

9 - water flow regulator;

10 - control unit.

The reaction vessel (1), in which the exothermic hydrolysis reaction takes place, through pneumatic inlet valves (5) communicates with two hydrogen accumulators (4), made in the form of containers partially filled with water. Hydrogen accumulators (4) are equipped with pressure sensors (7) and heat exchangers-coolers (8) for cooling water.

Hydrogen accumulators (4) through outlet valves (6) are pneumatically connected to the hydrogen delivery line (2). In addition, these accumulators are hydraulically connected to each other through a heat exchanger for the removal of reaction heat (3) and a water flow regulator (9).

The inlet and outlet valves (5, 6) and the water flow regulator (9) are controlled from the control unit (10), which is electrically connected to all valves (5, 6) and the water flow regulator (9). Pressure sensors (7) installed in hydrogen accumulators (4) are also connected to the control unit (10).

Such a hydrogen generator works as follows. Before hydrolysis in the reaction vessel (1) begins, one of the inlet valves (5) connecting the reaction vessel (1) with the corresponding hydrogen accumulator (4) is open, and the other inlet valve of this accumulator is closed. On the highway with an open inlet valve (5), hydrogen enters the corresponding hydrogen storage (4).

If the rate of pressure increase in this hydrogen accumulator (4) is sufficiently high (i.e., the reaction is violent and the heat generation in the reaction vessel is large), the water flow regulator (9) opens and cold water from one hydrogen accumulator begins to flow to another . Along the way, it removes heat from the reaction vessel (1), passing through a heat exchanger to remove reaction heat (3). At the same time, hydrogen, which was previously in the second hydrogen accumulator (not filled with water), is supplied to the consumer via a line with an open outlet valve (6) connecting this hydrogen store (4) to the hydrogen delivery line (2).

The cooling time of the reaction vessel (1) is determined by the amount of water stored in the hydrogen storage tanks (4), and the heat sink capacity is determined by the flow of cooling water through the heat exchanger to remove the reaction heat (3). Water consumption, in turn, is determined by the pressure of hydrogen in the hydrogen storage tanks (4) and the cross-sectional area in the water flow controller (9).

Thus, there is the possibility of both automatic cooling of the reacting mixture and a controlled cooling process.

After completing the cycle of the generator and displacing water from one hydrogen storage tank to another, the heated water in it is cooled by a heat exchanger-cooler and the process is repeated in the opposite direction.

Thus, the proposed technical solution allows you to create an autonomous hydrogen generator capable of cooling itself in automatic mode. This allows you to increase the reliability of its work, using the simplest control algorithms.

List of references

1. V.V. Rybakov. “The textbook of the gas welder”, MASHGIZ., Moscow, 1956, pp. 34-36.

2. "Device for generating heat and electricity from aluminum waste." Pat. US No. 4,218.520, 1980

3. "Hydrogen generation by hydrolysis for a power plant based on underwater fuel cells." Pat. 5372617, USA, 1994.

Claims (1)

A hydrogen generator operating on an exothermic hydrolysis reaction and containing a reaction vessel with a hydrogen delivery line and a heat exchanger for removing reaction heat, characterized in that two hydrogen storage devices equipped with pressure sensors are introduced into the generator, each hydrogen storage device being pneumatically connected through an inlet valve to a reaction vessel, and through an outlet valve, with a hydrogen delivery line, and the hydrogen stores are made in the form of sealed containers, partially filled with water and hydra nical connected to each other through a heat exchanger to remove heat of reaction and the water flow regulator, which, together with the valves electrically connected with the control unit to which is also connected the pressure sensors installed in the hydrogen storage medium.