RU2371813C1 - Autonomous power supply system and method of its operation - Google Patents

Abstract

FIELD: power engineering.

SUBSTANCE: invention is related to the field of autonomous power supply systems (APSS) for certain objects remote from power transmission lines, namely to APSS, which include renewable sources of energy as external source of electric energy, electrochemical generator (ECG), electrolytic cell and balloons for storage of reagents (hydrogen and oxygen). According to invention, autonomous power supply system comprises external source of electric energy, connected by supply buses to electric energy consumer, electrochemical generator based on fuel elements, electrolytic cell, hydrogen and oxygen balloons, connected by means of pipelines and valves to appropriate gas cavities of fuel elements in electrochemical generator and electrolytic cell and equipped with detectors of upper and lower permissible limit values of pressure, heat exchanger, coolant reservoir, circulating pump, at the same time fuel elements of electrochemical generator and electrolytic cell have common circuit of coolant circulation, it comprises: controller of coolant flow rate, inlet of which is connected to outlet of circulating pump, and one outlet is connected to inlet of coolant to electrolytic cell, the other one - to inlet of coolant to electrochemical generator, electronic converter, which provides for collection of electric energy by consumer from electrochemical generator, electronic converter, which provides for power collection by electrolytic cell, circuit of heat removal with additional circulating pump, mixer, one inlet of which is connected to common circulation circuit, and the other - to circuit of heat removal, and outlet of mixer is connected to inlet to coolant reservoir, and also pump of water supply to electrolytic cell from coolant reservoir is introduced, at the same time on pipeline, which connects outlet of mixer to inlet of coolant reservoir, there is a temperature detector installed, which is connected to additional circulating pump, and heat exchanger is installed in circuit of heat removal, moreover, electrochemical generator and electrolytic cell are connected to supply buses via according electronic converters. Method for operation of autonomous power supply system includes periodic consumption of electric energy from external source for water decomposition into oxygen and hydrogen in electrolytic cell and release of electric energy as a result of chemical reaction of oxygen and hydrogen in electrochemical generator, at the same time in period of consumption of electric energy produced from external source, for water decomposition into oxygen and hydrogen in electrolytic cell they also use part of electric energy from capacity of electrochemical generator, and as electric energy is released as a result of chemical reaction of oxygen and hydrogen in electrochemical generator, part of this released electric energy is used for water decomposition into oxygen and hydrogen in electrolytic cell. Besides in period of consumption of electric energy produced from external source, for water decomposition into oxygen and hydrogen in electrolytic cell they also used from 2% to 10% of electrochemical generator power, and when electric energy is released as a result of chemical reaction of oxygen and hydrogen in electrochemical generator, part of this released energy from 2% to 10% of electrolytic cell capacity is used for water decomposition into oxygen and hydrogen.

EFFECT: lower power inputs and improved efficiency of APSS at transition modes, and improved resource and reliability of APSS operation.

3 cl, 1 dwg

Description

The invention relates to the field of autonomous energy supply systems (ASEP) of individual objects remote from the power line, namely ASEP, including renewable energy sources as an external source of electricity, an electrochemical generator (ECG), an electrolyzer and cylinders for storing reagents (hydrogen and oxygen) .

As you know, renewable sources of electricity, such as solar panels or wind power plants, can not provide consumers with stable power throughout the day. This is due to the variability of both solar radiation and wind speed. Therefore, ASEPS containing ECG and an electrolyzer, in periods when external energy sources (solar panels or wind power plants) are not able to provide electricity to the consumer, the consumer receives electricity from ECG. During this period, electricity is obtained through the chemical reaction of a compound of oxygen with hydrogen. The chemical reaction of the combination of oxygen with hydrogen with the formation of water takes place on the fuel cells (FC) of the electrochemical generator. In periods when external energy sources (solar panels or wind power plants) provide electricity to the consumer, part of this electricity is used to decompose the resulting water into oxygen and hydrogen. The decomposition of the formed water into oxygen and hydrogen occurs on the electrolysis cells (EJ) of the electrolyzer. This method is implemented in an autonomous power supply system (patent RU 2277273 from 05.27.2006, IPC ⁶ : H01M 8/06; H01M 16/00), taken as a prototype. An autonomous energy supply system contains an external source of electricity connected to a consumer of electricity, an electrochemical generator based on fuel cells, an electrolyzer, hydrogen and oxygen cylinders connected by pipelines and valves to the corresponding gas cavities of the fuel cells of the electrochemical generator and electrolyzer and equipped with upper and lower maximum permissible sensors pressure values, heat exchanger, heat carrier capacity, circulation pump, while Livni elements of the electrochemical generator and the electrolyser have a common coolant circuit.

ASEP works as follows. In periods when external sources of energy (solar panels or wind power plants) are not able to supply electricity to the consumer, hydrogen and oxygen from the cylinders are supplied to the ECG. ECG generates a current that is supplied to the consumer. Water formed as a result of the reaction accumulates in the electrolyte capacity, causing it to dilute and increase in volume. The heat released during the operation of the ECG is removed by the electrolyte pumping circuit and discharged into the environment by the heat exchanger. In periods when external sources of energy (solar panels or wind power plants) provide electricity to the consumer, part of this electricity is used to decompose the resulting water into oxygen and hydrogen. This is implemented as follows. The electrolyte circulation circuit is disconnected from the ECG and connected to the electrolyzer, to which electricity is supplied from an external source of electricity. The alkaline electrolyte undergoes electrolysis at EE, decomposing water into oxygen and hydrogen, which leads to an increase in alkali concentration and a decrease in electrolyte volume. Hydrogen and oxygen generated during electrolysis accumulate in cylinders. When triggered by the sensors of the upper maximum permissible pressure in the reagent cylinders, the electrolyte circulation circuit is disconnected from the electrolyzer. An external source of electricity is disconnected from the electrolyzer. Power consumers during the switching components of ASEP made from the battery.

The disadvantages of the prototype are the small resource ASEP and the low reliability of its operation. This is due to the following:

- The use of an electrolyte as a coolant (a liquid whose circulation ensures the ASEP operation in a given temperature range) dramatically reduces the ASEP life and reliability, since the electrolyte is an aggressive liquid for many materials, for example, for widely used metals.

- A small resource and low reliability are also associated with the fact that when the ECG or the electrolyzer is inoperative for a long time (disconnecting the electric current circuits) and in the presence of reagents (hydrogen and oxygen) inside the cases, the resource and characteristics of both EC ECG and EY electrolyzer. This is due to the fact that when the electric current circuits are disconnected at the anode and cathode of both TE and EI, stagnant zones of positive and negative ions are formed, as a result of which the catalytic properties of the electrodes (anode and cathode) of both TE and EE sharply decrease. That is why during prolonged storage, ECG should always be in an atmosphere of inert gases (for example, argon, helium, nitrogen). With a minimum current collection from a fuel cell, which is determined experimentally, there are no stagnant zones of positive and negative ions, which ensures a minimum decrease in the characteristics of a fuel cell for the entire period of operation and a long service life.

At present, it has been experimentally proved that if the ECG operates continuously and the electricity supply during operation is in the range of 2-10%, then this provides a slight decrease in the current-voltage characteristics of the fuel cell for a long period of operation of more than 6000 hours. If ECG is located for a long time without power generation, in cases where there is no inert gas atmosphere on the fuel cell, the characteristics of the fuel cell and the ECG resource are reduced several times. The same applies to the EY of the electrolyzer. This means that the electrolyzer must constantly consume in the range from 2 to 10% of its maximum consumed electric power, so that the characteristics of the electromagnet are at the proper level.

The disadvantage of the prototype is also the long transition time from the mode of accumulation of electricity (operation mode of the electrolyzer only) to the mode of delivery of electricity to the consumer (operation mode only ECG) and vice versa. This is due to the fact that during the operation of any of the components of the ASEP (ECG or electrolyzer) according to the prototype, it is provided only by heat removal from the working unit. Consequently, the idle unit will cool. It is known that the operation of TE and EE can effectively begin only at temperatures above 60 ° C. Therefore, in order to ensure the start of operation of an idle unit, it must be heated to the required temperature. It should be noted that if an idle unit cools down to subzero temperatures (this depends on the climatic conditions of use), then this can damage the idle unit and, as a result, the entire ASEP.

Thus, the disadvantages of ASEP and its operation are: limited scope associated with inoperability at low temperatures, low reliability, as well as the complexity of its design and operation technology. This is due to the fact that in the prototype, the period of switching ASEP components from one mode to another is ensured by a battery, which complicates the process of an idle unit entering the operating mode and requires considerable time in order to warm up an idle unit to the required temperature.

The objective of the invention is the creation of ASEPS, providing a quick and reliable transition from one mode to another under operating conditions when the ambient temperature may be below 0 ° C, and the development of a reliable method of operating ASEP, devoid of these disadvantages.

The technical result is to reduce energy consumption and increase the speed of ASEP in transition modes; increasing the resource and reliability of ASEP operation.

The technical result is achieved by the fact that in an autonomous energy supply system containing an external source of electricity connected by power buses to the consumer of electricity, an electrochemical generator based on fuel cells, an electrolyzer, hydrogen and oxygen cylinders, connected through pipelines and valves with the corresponding gas cavities of the fuel cells of the electrochemical generator and electrolyzer and equipped with sensors of upper and lower maximum permissible pressure values, heat exchange nnik, coolant capacity, circulation pump, while the fuel cells of the electrochemical generator and the electrolyzer have a common coolant circulation loop, the following are introduced: a coolant flow controller, the input of which is connected to the output of the circulation pump, and one output is connected to the coolant inlet to the electrolyzer, the other to the input coolant into an electrochemical generator, an electronic converter that provides power to a consumer of electricity from an electrochemical generator, an electronic converter Atelier providing power supply to the electrolyzer, a heat removal circuit with an additional circulation pump, a mixer, one input of which is connected to a common circulation circuit, and the other to a heat removal circuit, and the mixer output is connected to the entrance to the coolant tank, and a water supply pump is introduced a temperature sensor is connected to the additional circulation pump, and a heat exchanger is installed in the electrolyzer from the coolant tank, while on the pipeline connecting the mixer output to the coolant tank inlet lined in the heat removal circuit, and the electrochemical generator and the electrolyzer are connected to the power buses through the corresponding electronic converters.

The specified technical result is also achieved by the fact that in the method of operating an autonomous energy supply system, including periodic consumption of electricity from an external source, for the decomposition of water into oxygen and hydrogen in the electrolyzer and the release of electricity as a result of the chemical reaction of oxygen and hydrogen in an electrochemical generator, while the period of consumption of electricity received from an external source for the decomposition of water into oxygen and hydrogen in the electrolyzer also use part of the electric power argy from the power of the electrochemical generator, and during the release of electricity as a result of the chemical reaction of oxygen and hydrogen in the electrochemical generator, part of this generated electricity is used to decompose water into oxygen and hydrogen in the electrolyzer.

In addition, during the period of consumption of electricity received from an external source, from 2 to 10% of the power of the electrochemical generator is also used for the decomposition of water into oxygen and hydrogen in the electrolytic cell, and part of this energy when the energy is released as a result of the chemical reaction of oxygen and hydrogen in the electrochemical generator released energy from 2 to 10% of the electrolytic capacity is used to decompose water into oxygen and hydrogen.

In the proposed ASEP and the method of its operation, both the ECG and the electrolyzer operate continuously in all periods of operation. This means that during the period of accumulation of electricity, during the period of operation of the electrolyzer, the decomposition of water occurs not only due to the electricity received from an external source, but also due to the electricity received as a result of the chemical reaction of oxygen and hydrogen, that is, as a result of the operation of ECG. This allows, due to the heat generated during the operation of the ECG, to ensure the temperature of the ECG in a given range during the period of energy storage. In the period when the consumer receives electricity only from the ECH, the ECH supplies electricity not only to the consumer, but also to EE. This allows, due to the heat generated during the operation of the electrolysis cells, to ensure the temperature of the cell in a predetermined range during the period of the generation of ECG electricity to the consumer.

The invention is illustrated in the drawing, which shows a schematic diagram of ASEP, where it is indicated:

1 - an external source of electricity;

2 - electricity consumer;

3 - electrochemical generator (ECG);

4 - electrolyzer;

5 - hydrogen cylinder;

6 - oxygen cylinder;

7 - pipelines;

8 - hydrogen valve;

9 - oxygen valve;

10 - general circuit of the coolant circulation;

11 - heat carrier capacity;

12 - circulation pump;

13 - heat exchanger;

14 - mixer;

15 - temperature sensor;

16 - circulation pump;

17 - sensor of the upper and lower maximum permissible hydrogen pressure;

18 - sensor upper and lower maximum allowable oxygen pressure;

19 - flow rate controller;

20 - an electronic converter that provides power reception electrolyzer;

21 - an electronic Converter that provides power to the consumer of electricity from the ECG;

22 - water supply pump;

23 - loop heat removal;

24 - power bus.

ASEP includes an external source of electricity 1, for example, a solar battery or a wind turbine that supplies electrical energy to consumer 2, and also supplies power through an electronic converter 20, which provides power to the electrochemical cell 4. In the absence of power from the primary source, energy is supplied from the terminals ECG 3 through an electronic Converter 21, providing power to the consumer of electricity from ECG. Consumer power is provided by 24 power buses.

Hydrogen 5 and oxygen 6 cylinders with sensors of upper and lower maximum permissible values of hydrogen pressures 17 and oxygen 18, respectively, and valves 8 and 9 are connected by pipelines 7 to the corresponding gas cavities of the electrochemical cell and the electrochemical cell. The general circulation circuit of the coolant 10 with a capacity of 11, a circulation pump 12, a flow rate regulator 19 for changing the fluid flow when changing the operating modes of the ASEP is connected to both the ECG 3 and the electrolyzer 4.

A heat exchanger 13, for discharging excess heat into the environment, which enters the heat removal circuit 23, is connected to one of the inputs of the mixer 14, the other input of the mixer is connected to a common circulation circuit of the heat carrier 10. The output of the mixer 14 is connected by a pipe on which the temperature sensor 15 is mounted , with the capacity of the coolant 11. The signal from the temperature sensor 15 is supplied to control the operation of the circulation pump 16. The water supply pump 22 connects the tank 11 to the electrolyzer 4.

ASEP works as follows.

During the period of operation of an external source of electric power 1, for example, a solar battery, electricity is supplied to power consumer 2 via power buses 24, and also through an electronic converter 20 to the terminals of electrolyzer 4, providing power to the EJ. An insignificant part of electricity (2-10%) during this period also comes from the ECG terminals 3. The signal that the electrolyzer 4 can start working, that is, decompose water into hydrogen, which should fill the hydrogen cylinder 5, and oxygen, which should fill the oxygen cylinder 6 comes either from the sensor 17 or from the sensor 18. This is due to the fact that the pressure in the cylinder 5 and in the cylinder 6 are always equal to each other, since the internal cavities of these cylinders are connected with the EJ, the pressure drop on which is not allowed. The regulation of the difference in the EJ is provided by the electrolyzer armature. The same signal either from the sensor 17 or from the sensor 18 enters the flow rate regulator of the coolant 19. As a result, as soon as the electrolyzer 4 begins to decompose water into oxygen and hydrogen, and the operation of the electrolyzer 4 always occurs with the release of heat through the surface of the electrolyzer 4, in contact with the coolant that is pumped by the circulation pump 12, the maximum flow rate of the coolant will pass, removing the heat generated, and through the surface of the ECG 3 in contact with the coolant, the minimum flow of heat will pass carrier, providing the temperature of the ECG 3 so that it does not fall below a predetermined level.

The temperature of the hot heat carrier in the circuit 10 will depend on the amount of heat released during the operation of the electrolyzer 4. The hot heat carrier is mixed in the mixer 14 with a cooled heat carrier, which, pumping by the circulation pump 16, through the heat exchanger 13, is cooled to the ambient temperature in the heat removal circuit 23 As a result of such mixing, the temperature of the coolant coming from the mixer 14 into the tank 11 will always be higher than the ambient temperature. The temperature of the coolant coming from the mixer 14 to the tank 11 is maintained in a predetermined temperature range, for example, ~ 60 ° C by controlling the flow rate of the cooled coolant, which is pumped by the circulation pump 16 through the heat exchanger 13. The flow rate of the cooled coolant is controlled by changing the flow rate of the circulation pump 16 the signals of the temperature sensor 15. The water supply pump 22 constantly supplies water from the tank 11 to the electrolytic cell 4 with a pressure that is fixed in the tanks 5 and 6.

In the period when the voltage of the external electric power source 1, for example, the solar battery, drops below the permissible level, the electricity to the power bus 24 comes from the terminals of the ECG 3 through an electronic converter 21, which provides power to the consumer of electricity. In this case, the main part of the electricity goes to the consumer 2, and a small part of the electricity (2-10%) in this period goes through the electronic converter 20, to the terminals of the electrolyzer 4. When the cable network is opened, a signal is sent to the fluid flow regulator 19. As a result, through the surface of the ECG 3 in contact with the coolant that is pumped by the circulation pump 12 will pass the maximum flow rate of the coolant, removing the heat generated, and through the surfaces of the electrolyzer 4, in contact In addition to the coolant, the minimum flow rate of the coolant will pass, ensuring the temperature of the cell 3 so that it does not fall below a predetermined level.

The temperature of the hot coolant in circuit 10 will depend on the amount of heat released during the operation of the ECG 3. The hot coolant is mixed in the mixer 14 with a cooled coolant, which, pumping by the circulation pump 16, through the heat exchanger 13, is cooled to ambient temperature. As a result of such mixing, the temperature of the coolant coming from the mixer 14 into the tank 11 will always be higher than the ambient temperature. The temperature of the coolant coming from the mixer 14 to the tank 11 is maintained in a predetermined temperature range, for example, ~ 60 ° C by controlling the flow rate of the cooled coolant that is pumped by the circulation pump 16 through the heat exchanger 13. The flow rate of the cooled coolant is controlled by changing the flow rate of the circulation pump 16 according to the signals of the temperature sensor 15.

The essence of the method is as follows.

In periods when external energy sources (solar panels or wind power plants) provide electricity to both the consumer and the electrolyzer, which receives electricity not only from external sources, but also necessarily in the range from 2 to 10% of the ECG power. This allows the ECG to be constantly maintained in working condition. As a result, the temperature of the ECG will be within the specified permissible operating limits. In the event of an unexpected failure of an external source of electricity, the ECG will be instantly connected to the delivery of the necessary electricity to the consumer. There is no need to warm up the ECG, go to the set mode, etc. (The prototype introduced a battery for this purpose.)

In periods when external energy sources do not give electricity to the consumer, and the consumer receives electricity only from ECG due to the chemical reaction of oxygen and hydrogen, part of this electricity, namely in the range from 2 to 10% of the total power consumption of the electrolyzer, is used to decompose water into oxygen and hydrogen in the electrolyzer. This allows you to maintain in a given operating mode and eliminate the need for heating the cell and its gradual exit to a given operating mode.

Thus, the proposed autonomous power supply system and the method of its operation allow:

- significantly reduce energy consumption and increase the performance of ASEP in transition modes;

- significantly increase the reliability and resource ASEP.

Claims (3)

1. An autonomous energy supply system containing an external source of electricity connected by power buses to an electricity consumer, an electrochemical generator based on fuel cells, an electrolyzer, hydrogen and oxygen cylinders connected by pipelines and valves to the corresponding gas cavities of the fuel cells of the electrochemical generator and electrolyzer and equipped with sensors upper and lower maximum permissible pressure values, heat exchanger, heat carrier capacity, circulating th pump, while the fuel cells of the electrochemical generator and the electrolyzer have a common coolant circulation circuit, characterized in that it includes: a coolant flow controller, the input of which is connected to the output of the circulation pump, and one output is connected to the coolant inlet to the electrolyzer, the other to the coolant inlet into the electrochemical generator, an electronic converter that provides power to the consumer of electricity from the electrochemical generator, an electronic converter, providing receiving power by the electrolyzer, a heat removal circuit with an additional circulation pump, a mixer, one input of which is connected to a common circulation circuit and the other to a heat removal circuit, and the mixer output is connected to the inlet to the coolant tank, and a water supply pump to the electrolyzer is introduced from the coolant tank, at the same time, a temperature sensor is installed on the pipeline connecting the mixer output to the coolant tank inlet, connected to an additional circulation pump, and the heat exchanger is installed in the circuit with heat recovery, moreover, the electrochemical generator and the electrolyzer are connected to the power buses through the corresponding electronic converters. 2. A method of operating an autonomous energy supply system, including periodic consumption of electricity from an external source, for decomposing water into oxygen and hydrogen in the electrolyzer and the release of electricity as a result of a chemical reaction of oxygen and hydrogen in an electrochemical generator, characterized in that during the period of consumption of electricity received from external source, for the decomposition of water into oxygen and hydrogen in the electrolyzer also use part of the electricity from the power of the electrochemical generator, the allocation of electric power by a chemical reaction of oxygen and hydrogen in an electrochemical generator part of the allocated power is used to decompose water into hydrogen and oxygen in an electrolyzer. 3. The method of operating the autonomous energy supply system according to claim 2, characterized in that from the time of consumption of electricity received from an external source, from 2 to 10% of the power of the electrochemical generator is also used to decompose water into oxygen and hydrogen in the electrolytic cell, and when releasing electricity as a result of a chemical reaction of oxygen and hydrogen in an electrochemical generator, a part of this allocated energy from 2 to 10% of the electrolytic power is used to decompose water into oxygen and hydrogen.

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