JP5602698B2 - Power conversion system - Google Patents

Description

  The present invention relates to a power conversion system that generates power using exhaust heat of a heat engine.

Examples of energy storage means that can store natural energy and relax the supply and demand balance of electric power include those using organic hydrides.
When heated in the presence of a predetermined catalyst, the organic hydride generates hydrogen and a dehydrogenated product composed of, for example, an aromatic hydrocarbon by a dehydrogenation reaction. Further, when this dehydrogenated product and hydrogen are reacted in the presence of a predetermined catalyst, an organic hydride is generated. Therefore, for example, water can be electrolyzed using electricity obtained from natural energy such as sunlight and geothermal heat, and hydrogen obtained by this electrolysis can be stored in high density as an organic hydride.
Conventionally, a hydrogen supply system that supplies hydrogen extracted from an organic hydride is known (see, for example, Patent Document 1). This hydrogen supply system is configured to generate hydrogen from organic hydride using the high-temperature exhaust gas of the combustion turbine power generator as a heat source.

JP 2004-197705 A

  However, it is difficult for the conventional hydrogen supply system (see, for example, Patent Document 1) to use the high-temperature exhaust gas heat of the combustion turbine to generate hydrogen from the organic hydride. In other words, the conventional hydrogen supply system has a problem in that excess heat of exhaust gas is discarded and energy conversion efficiency is low.

  Then, the subject of this invention is providing the power conversion system excellent in energy conversion efficiency using an organic hydride.

The power conversion system of the present invention that solves the above problems includes a hydrogen generator that generates hydrogen and a dehydrogenated product of organic hydride by heating the supplied organic hydride in the presence of a predetermined catalyst, and the hydrogen generator. Separation device for separating hydrogen obtained from organic hydride dehydrogenated product and sending hydrogen, power conversion device for obtaining power by burning hydrogen sent from the separation device, and discharge from the power conversion device Power is generated by the heat exchanger that exchanges heat between the exhaust gas to be supplied and the organic hydride before being supplied to the hydrogen generator, and the organic hydride that is superheated by heat exchange in the heat exchanger And an expander for delivering the organic hydride to the hydrogen generator.
According to this power conversion system, the organic hydride is heated by exhaust heat from the power conversion device, and the organic hydride that has become superheated steam is supplied to the expander to obtain power. The organic hydride that has passed through the expander is supplied to a hydrogen generator to generate hydrogen, which is used as fuel when the power converter generates power.

  ADVANTAGE OF THE INVENTION According to this invention, the power conversion system excellent in energy conversion efficiency can be provided using an organic hydride.

1 is a configuration explanatory diagram of a power conversion system according to a first embodiment of the present invention. FIG. (A) is sectional drawing of the hydrogen generator of a power conversion system, (b) is sectional drawing of the reaction cell incorporated in a hydrogen generator, (c) is sectional drawing of the reaction sheet incorporated in a reaction cell. is there. It is composition explanatory drawing of the power conversion system which concerns on 2nd Embodiment of this invention. It is composition explanatory drawing of the power conversion system which concerns on 3rd Embodiment of this invention. It is a structure explanatory view of the power conversion system concerning a 4th embodiment of the present invention. It is composition explanatory drawing of the power conversion system which concerns on 5th Embodiment of this invention. In the power conversion system concerning a 5th embodiment of the present invention, it is a time chart explaining the timing of the drive or stop of boost pump P1, switching of valve V3, and opening and closing of valve V4. It is a flowchart which shows the procedure in which the controller of the power conversion system which concerns on 5th Embodiment of this invention performs switching of valve | bulb V3, and control of opening and closing of valve | bulb V4.

Hereinafter, the first to fourth embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
(First embodiment)
As shown in FIG. 1, a power conversion system S according to the present embodiment includes a hydrogen generator 1, a separator 2, a power converter 4 having a first expander 3, etc., a heat exchanger 5, 2 expander 6. The first expander 3 corresponds to “an expander that generates power by hydrogen combustion gas from a hydrogen combustion device” in the claims. The second expander 6 corresponds to “an expander that generates power using an organic hydride and sends the organic hydride to a hydrogen generator” in the claims.
This power conversion system S generates power using the power obtained by using organic hydride, and generates power by burning the hydrogen obtained from this organic hydride while generating power using the superheated steam of the organic hydride. It is the composition which makes it.
The first expander 3 is composed of a gas turbine that supplies hydrogen combustion gas, and the second expander 6 is composed of a steam turbine that supplies superheated steam of organic hydride.

The organic hydride is a hydride of an aromatic hydrocarbon, and stores hydrogen in a releasable manner by adding hydrogen to a carbon-carbon double bond of the aromatic hydrocarbon.
Examples of the organic hydride include monocyclic hydrogenated aromatics such as cyclohexane, methylcyclohexane and dimethylcyclohexane, bicyclic hydrogenated aromatics such as tetralin, decalin and methyldecalin, and tetradecahydroanthracene. And cyclic hydrogenated aromatics. When heated in the presence of a predetermined catalyst, the organic hydride is decomposed into hydrogen and the aromatic hydrocarbon which is a dehydrogenated product of the organic hydride. Incidentally, examples of the dehydrogenated product of organic hydride include benzene, toluene, xylene, mesitylene, naphthalene, methylnaphthalene, and anthracene.

The organic hydride will be described in more detail by taking the above-mentioned methylcyclohexane [C ₆ H ₁₁ (CH ₃ )] as an example. As shown in the following formula (1), methylcyclohexane is a dehydrogenated product of hydrogen (H ₂ ) and organic hydride. To toluene [C ₆ H ₅ (CH ₃ )].
C ₆ H ₁₁ (CH ₃ ) → C ₆ H ₅ (CH ₃ ) + 3H ₂ −205 kJ (1)
Incidentally, the reaction represented by the formula (1) is an endothermic reaction, and it is desirable to carry out the reaction under heating since 205 kJ of heat is absorbed when 3 mol of hydrogen is produced from 1 mol of methylcyclohexane. . In this embodiment, the heating temperature is set to about 300 to 400 ° C. on the assumption that methylcyclohexane is used as the organic hydride, but this heating temperature depends on the type of the organic hydride used. It can be set as appropriate.

The hydrogen generator 1 uses organic hydride supplied from a first tank 7 described later, which stores organic hydride via a separation device 2, a heat exchanger 5 and a second expander 6 described later, as a dehydrogenated product. It decomposes into hydrogen. In FIG. 1, symbol P1 is a booster pump that boosts the organic hydride in the first tank 7 and supplies it to the second expander 6 side, and symbol V1 is a valve. It is provided in the middle of piping connecting between the separator 2. These booster pump P1 and valve V1 are for adjusting the flow rate, flow velocity, pressure, etc. of the organic hydride delivered from the first tank 7 toward the separation device 2.
2A to be referred to next is a sectional view of the hydrogen generator, FIG. 2B is a sectional view of a reaction cell built in the hydrogen generator, and FIG. 2C is built in the reaction cell. It is sectional drawing of a reaction sheet.

As shown in FIG. 2A, the hydrogen generator 1 includes a plurality of reaction cells 31 whose outer shape is columnar, and a cylindrical first casing 32 that houses these reaction cells 31. Yes. And in each reaction cell 31, the organic hydride (for example, methylcyclohexane) stored in the 1st tank 7 shown in FIG. 1 has the separation apparatus 2, the heat exchanger 5, and the 2nd expander 6 which are mentioned later. Sent through.
A high-temperature hydrogen combustion gas from the hydrogen combustion device 8 described later flows through the gap formed between the reaction cells 31.
The first casing 32 and the second casing 34 to be described later are made of metal (for example, SUS) so as to have high thermal conductivity. In addition, the shape of the 1st casing 32 and the 2nd casing 34 is not limited to a cylindrical shape, For example, a square cylinder shape and a polygonal cylinder shape may be sufficient.

As shown in FIG. 2B, the reaction cell 31 includes a plurality of stacked reaction sheets 33 and a second casing 34 that accommodates the plurality of reaction sheets 33.
As shown in FIG. 2 (c), each reaction sheet 33 includes a base metal foil 35, a porous layer 36 formed on each surface of the metal foil 35, and a catalyst 37 supported on the porous layer 36. And. That is, each reaction sheet 33 has a three-layer structure in which the porous layer 36 supported by the catalyst 37, the metal foil 35, and the porous layer 36 supported by the catalyst 37 are stacked in this order.
Note that a gap is formed between the reaction sheets 33 adjacent to each other in the thickness direction so that the organic hydride, generated hydrogen, and dehydrogenated product (for example, toluene) can flow therethrough.

Further, since the reaction sheet 33 is in the form of a sheet, its heat capacity is small, heat is quickly conducted through the reaction sheet 33, and the temperature of the catalyst 37 is quickly raised to a temperature at which the catalyst function is exhibited well. Thereby, the efficiency of the decomposition reaction which decomposes | disassembles an organic hydride into hydrogen and a dehydrogenation thing is high.
Further, each reaction sheet 33 is formed with a plurality of through holes 33a. As a result, the heat of the hydrogen combustion gas is conducted well in the thickness direction, and the organic hydride, the generated hydrogen, and the dehydrogenated product are also flowed well in the thickness direction.
The metal foil 35 is made of, for example, an aluminum foil and has a thickness of about 50 to 200 μm. However, the metal foil 35 may not be provided, or instead of the metal foil 35, a porous layer serving as a base may be provided, and the entire reaction sheet 33 may have a porous structure.

The porous layer 36 is a layer for supporting the catalyst 37 and has a plurality of pores through which the organic hydride, the generated hydrogen, and the dehydrogenated product can flow. Such a porous layer 36 can be formed of, for example, an oxide mainly composed of alumina, titania, silica, zirconia or the like. The catalyst 37 decomposes the organic hydride to generate hydrogen and dehydrogenated product. It is a catalyst. Such a catalyst 37 is composed of at least one selected from, for example, platinum, nickel, palladium, rhodium, iridium, ruthenium, molybdenum, rhenium, tungsten, vanadium, osmium, chromium, cobalt, iron and the like.

Incidentally, the hydrogen combustion gas flowing through the hydrogen generator 1 (see FIG. 1) passes through a predetermined pipe (not shown) connected to the hydrogen generator 1 and is discharged to the outside of the hydrogen generator 1. It has become.
The temperature of the hydrogen generator 1 can be adjusted by the temperature of the hydrogen combustion gas sent from the heat exchanger 5 toward the hydrogen generator 1 and the flow rate of the hydrogen combustion gas. In addition, as described above, the temperature of the hydrogen generator 1 in the present embodiment is assumed to be set to about 300 to 400 ° C. on the assumption that methylcyclohexane is used as the organic hydride. It is not limited to these, and can be appropriately set within the range of the decomposition temperature according to the type of organic hydride to be used.

  Returning to FIG. 1 again, as the separation device 2, a dehydrogenated product (for example, toluene) of the high-temperature organic hydride (for example, methylcyclohexane) delivered from the hydrogen generator 1 and a hydrogen mixture are dehydrogenated. By cooling to a temperature below the boiling point of the hydride (bp: less than 111.degree. C. in the case of toluene), the dehydrogenated product as a liquid and the hydrogen as a gas are separated from each other. Then, the separation device 2 sends the separated hydrogen to the power conversion device 4 described later.

The separation device 2 in the present embodiment exchanges heat between the organic hydride supplied from the first tank 7 and the mixture of the dehydrogenated product and hydrogen delivered from the hydrogen generating device 1, so that the gas as a gas The dehydrogenated product is cooled and condensed. As a specific configuration, for example, a cooling pipe through which an organic hydride supplied from the first tank 7 flows is disposed in a chamber into which a mixture of dehydrogenated product and hydrogen flows.
In the separation device 2, the organic hydride supplied from the first tank 7 is preheated by a mixture of dehydrogenated product and hydrogen before being supplied to the heat exchanger 5 described later.

As the power conversion device 4, a hydrogen combustion device 8 that combusts hydrogen sent from the separation device, an axial flow type compressor 9 that sends compressed air to the hydrogen combustion device 8, and a hydrogen combustion device 8 An expansion turbine that generates power using high-temperature and high-pressure hydrogen combustion gas, and includes a first expander 3 that is coaxially connected to the compressor 9.
The output shaft of the first expander 3 is connected to the input shaft of the first generator 10. That is, the first generator 10 generates power using the power generated by the power conversion device 4.
The first expander 3 sends high-temperature hydrogen combustion gas to a heat exchanger 5 described later.

  The heat exchanger 5 is configured to exchange heat between the high-temperature hydrogen combustion gas exhausted from the first expander 3 and the organic hydride preheated by the separation device 2. Accordingly, the organic hydride delivered from the separation device 2 becomes superheated steam exceeding 300 ° C. and is supplied to the next second expander 6.

The second expander 6 is composed of an expansion turbine, and generates power by organic hydride that has become high-temperature and high-pressure superheated steam supplied from the heat exchanger 5. The output shaft of the second expander 6 is connected to the input shaft of the second generator 11. That is, the second generator 11 is configured to generate power with the power generated by the second expander 6 by the organic hydride that has become superheated steam.
The second expander 6 is configured to send a high temperature organic hydride gas to the hydrogen generator 1 described above. Incidentally, the temperature of this organic hydride gas is maintained at about 300 to 400 ° C.

Such a power conversion system S according to the first embodiment includes the second tank 12 that stores the dehydrogenated product of the organic hydride separated by the separation device 2.
In the power conversion system S according to the present embodiment, it is assumed that all of the organic hydride gas supplied to the hydrogen generator 1 is decomposed into its dehydrogenated product and hydrogen (decomposition rate 100). %), When the decomposition rate of the organic hydride is less than 100%, the undecomposed organic hydride is recovered in the second tank 12 as a liquid.
Although not shown, the power conversion system S according to the first embodiment includes a compressor that compresses hydrogen and sends it to the hydrogen combustion device 8 in the middle of a pipe connecting the separation device 2 and the hydrogen combustion device 8. Can be arranged.

According to the power conversion system S according to the first embodiment as described above, the hydrogen generator 1 efficiently uses the heat (exhaust heat) of the exhaust gas from the power conversion device 4 from the organic hydride. Hydrogen can be generated. Moreover, power generation can be performed by converting the exhaust heat described above into expansion work (power) by the second expander 6. Electric power can be generated by converting the heat generated by burning the generated hydrogen into expansion work (power) in the first expander 3. Thereby, the power conversion system S is excellent in energy conversion efficiency.
The second expander 6 and the second generator 11 may be connected on the same axis or via a transmission. According to such a configuration, the second generator 11 at the start can operate as a motor.

(Second Embodiment)
Next, a power conversion system S according to a second embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 3, the power conversion system S according to the present embodiment is replaced with the second expander 6 (see FIG. 1) used in the power conversion system S (see FIG. 1) according to the first embodiment. The second embodiment is the same as the first embodiment except that the expander type hydrogen generator 20 is used and the hydrogen generator 1 (see FIG. 1) provided on the downstream side of the second expander 6 (see FIG. 1) is omitted. It is configured. That is, in the second embodiment, the expander-type hydrogen generator 20 also serves as the hydrogen generator 1 and the second expander 6 in the first embodiment. Hereinafter, the expander-type hydrogen generator 20 will be mainly described, and the same components as those in the first embodiment will be denoted by the same reference numerals and detailed description thereof will be omitted.

  The expander-type hydrogen generator 20 shown in FIG. 3 includes the above-described catalyst so as to face a flow path through which an organic hydride gas that has become superheated steam flows, while being constituted by an expansion turbine. As an arrangement position of the catalyst, the vicinity of the outlet for sending the organic hydride gas toward the separation device 2 is desirable. Incidentally, the catalyst is filled in a predetermined casing (not shown), and this casing is disposed on the flow path of the organic hydride gas.

  Further, the catalyst can be directly supported on the turbine blade of the above-described expansion turbine. According to the expander-type hydrogen generator 20 including such an expansion turbine, when hydrogen and a dehydrogenated product are generated from the organic hydride by the catalytic action on the surface of the turbine blade that rotates at high speed, the density difference between them is generated. Makes it easier to separate them (by centrifugal force). As a result, the reaction temperature (decomposition temperature) of the organic hydride can be lowered by reducing the partial pressure of the dehydrogenated product in the reaction system. Specifically, if the lower limit of the reaction temperature of the organic hydride in the expander type hydrogen generator 20 in which the catalyst is not supported on the turbine blade is about 250 ° C., the expander type hydrogen in which the catalyst is supported on the turbine blade. The lower limit of the reaction temperature of the organic hydride in the generator 20 can be lowered to about 150 ° C.

Further, the expander type hydrogen generator 20 can be provided with a hydrogen separation membrane (not shown) for separating hydrogen from a mixture containing undecomposed organic hydride, generated hydrogen, and dehydrogenated product.
As the position of the hydrogen separation membrane, there is a bypass path Bp that connects a predetermined gas outlet of the expansion turbine constituting the expander-type hydrogen generator 20 and a path for supplying hydrogen from the separator 2 to the hydrogen combustion apparatus 8. It is desirable to provide the vicinity of the gas outlet that is the base end of the path route Bp. An example of such a hydrogen separation membrane is a palladium alloy membrane.
According to the configuration (bleeding configuration) in which hydrogen is extracted halfway from the expander-type hydrogen generator 20 (expansion turbine) with such a hydrogen separation membrane, the enthalpies before and after the expander-type hydrogen generator 20 (expansion turbine) Since the difference can be increased, the output of the expansion turbine can be increased. As a result, the efficiency of the power conversion system S is further improved.

In the power conversion system S provided with such an expander-type hydrogen generator 20, the expander-type hydrogen generator 20 generates power by the organic hydride that has become high-temperature and high-pressure superheated steam supplied from the heat exchanger 5. It is configured as follows. The output shaft of the expander-type hydrogen generator 20 in this embodiment is connected to the input shaft of the second generator 11. In other words, the second generator 11 is configured to generate power with the power generated by the expander-type hydrogen generator 20 using the organic hydride gas that has become superheated steam.
In the expander-type hydrogen generator 20, when high-temperature organic hydride gas passes through the casing (not shown), the organic hydride gas comes into contact with the catalyst, thereby dehydrogenating hydrogen and organic hydride. It is decomposed into a compound. Thereafter, the mixture of hydrogen and the dehydrogenated product is sent out from the outlet of the expander-type hydrogen generator 20 toward the separator 2 in the form of a gas. Incidentally, the separation device 2 serves as a condenser (condenser) that condenses the dehydrogenated product that has exited the expander-type hydrogen generator 20, and greatly improves the output of the expander-type hydrogen generator 20.

  According to the power conversion system S according to the present embodiment as described above, the same effects as the power conversion system S according to the first embodiment (see FIG. 1) can be obtained, and the hydrogen in the first embodiment can be obtained. Since the generator 1 can be omitted, it is possible to reduce the size of the system. Further, since the expander type hydrogen generator 20 is configured to generate hydrogen by decomposing an organic hydride in an expansion turbine that generates power, according to the power conversion system S provided with this, separately, The energy conversion efficiency is further improved by improving the thermal efficiency (by preventing the heat loss from being reduced) as compared with the case where the hydrogen generator 1 is provided.

(Third embodiment)
Next, a power conversion system S according to a third embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 4, the power conversion system S according to this embodiment is a power conversion device 4 (see FIG. 1) used in the power conversion system S (see FIG. 1) according to the first embodiment. 1, except that an engine 13 (internal combustion engine) is used instead of the hydrogen combustion device 8, the compressor 9, and the first expander 3 shown in FIG. 1. Hereinafter, the engine 13 (an internal combustion engine as a power conversion device) will be mainly described, and the same components as those in the first embodiment are denoted by the same reference numerals and detailed description thereof will be omitted.
The second expander 6 (see FIG. 1) in the first embodiment is simply “expander 6” in the present embodiment because the first expander 3 (see FIG. 1) is omitted as described above. (Refer to FIG. 4) (the same applies to the next fourth embodiment (see FIG. 5)).

The engine 13 shown in FIG. 4 generates power by burning fuel (such as petroleum or natural gas) stored in the third tank 14 and the hydrogen obtained by decomposing organic hydride. The engine 13 corresponds to an “internal combustion engine” in the claims.
The engine 13 may be either a reciprocating type or a rotary type. The engine 13 may be either a spark ignition method or a compression ignition method.
Air is supplied to the engine 13 to a predetermined intake system, and exhaust gas from the exhaust system of the engine 13 is supplied to the heat exchanger 5.
Examples of the fuel supplied from the third tank 14 to the engine 13 via the pump P2 and the valve V2 include hydrocarbon fuels such as light oil, kerosene, heavy oil, natural gas, LPG, and gasoline.

Hydrogen is delivered from the separation device 2. Since this hydrogen is rich in flammability (flammability), when the engine 13 is of the spark ignition type, the hydrogen supplied from the separation device 2 can be directly introduced into the combustion chamber of the engine 13. The hydrogen is mixed with the fuel introduced into the combustion chamber and burned by spark ignition.
When the engine 13 is of the compression ignition type, hydrogen is premixed with air and then introduced into the combustion chamber, and fuel from the third tank 14 is injected into the combustion chamber at the time of compression ignition. That is, when the injected fuel is self-ignited by compression, hydrogen in the combustion chamber is ignited (compressed self-ignition diffusion combustion).
Incidentally, since hydrogen has a higher combustion speed than hydrocarbon fuel (fuel from the third tank 14), the ignition timing is advanced in the spark ignition type engine, and the hydrocarbon fuel (first fuel in the compression ignition type engine). The thermal efficiency of the engine 13 can be increased by advancing the injection timing of the fuel from the three tanks 14.
Note that the first generator 10 in FIG. 4 has an input shaft connected to the output shaft of the engine 13, and generates power using the power generated by the engine 13.

  According to the power conversion system S according to the present embodiment as described above, the same effects as the power conversion system S (see FIG. 1) according to the first embodiment are exhibited, and power is generated by the power of the engine 13. As a result, the system can be reduced in size and efficiency.

(Fourth embodiment)
Next, a power conversion system S according to a fourth embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 5, the power conversion system S according to the present embodiment includes a power conversion system S according to the third embodiment (FIG. 4) except that it includes an organic hydride preheating device 15 that uses engine exhaust heat. Reference) is configured. Below, the preheating apparatus 15 is mainly demonstrated, the same code | symbol is attached | subjected about the component similar to 3rd Embodiment, and detailed description is abbreviate | omitted.

The preheating device 15 shown in FIG. 5 includes a second heat exchanger 19 provided on the upstream side of the radiator 17 on the engine cooling water circulation path 18 having the radiator 17. The term “second” in the second heat exchanger 19 is due to the fact that the heat exchanger 5 shown in FIG. 4 is the first heat exchanger 5 in this embodiment.
Further, on the upstream side of the radiator 17 in the circulation path 18, a valve V <b> 3 is provided in parallel with the second heat exchanger 19.

The second heat exchanger 19 constituting the preheating device 15 in the present embodiment includes high-temperature engine cooling water sent from the engine 13 to the radiator 17 and organic hydride sent from the first tank 7 toward the separation device 2. Heat exchange.
In other words, the preheating device 15 collects the exhaust heat of the engine 13 through the engine cooling water, and the organic hydride that is later superheated by the first heat exchanger 5 by the recovered exhaust heat. It is configured to preheat. Incidentally, as described above, the organic hydride is preheated also in the separation device 2.
The valve V3 is a flow rate adjustment valve, and can adjust the flow rate of the engine coolant that bypasses the second heat exchanger 19 according to the opening thereof. Therefore, according to the valve V3, by adjusting the opening degree, it is possible to efficiently perform the preheating of the organic hydride by the preheating device 15 while maintaining the predetermined heat dissipation efficiency of the engine cooling water by the radiator 17. .

  According to the power conversion system S according to the present embodiment as described above, the same operational effects as those of the power conversion system S according to the third embodiment (see FIG. 4) can be obtained. Can play.

  In the conventional engine, about 30% of the heat quantity of the input fuel is discarded into the atmosphere by the exhaust gas and the engine cooling water, respectively. According to the power conversion system S according to this embodiment, the first from the exhaust gas of the engine 13 The organic hydride supplied to the expander 6 is superheated by the heat recovered by the heat exchanger 5, and the first heat exchanger 5 is heated by the heat recovered by the second heat exchanger 19 from the high-temperature engine cooling water. The supplied organic hydride can be preheated. Thus, according to the power conversion system S according to the present embodiment having the preheating device 15, the energy conversion efficiency is further improved by further improving the thermal efficiency.

  Further, according to the power conversion system S according to the present embodiment, the temperature of the heat medium (exhaust gas or engine cooling water) that heats the organic hydride before the organic hydride in the first tank 7 is sent to the expander 6. The 2nd heat exchanger 19, the separation apparatus 2, and the 1st heat exchanger 5 are arranged in order with low. Thereby, the power conversion system S which concerns on this embodiment can make a heat exchange rate higher between these heat media.

(Fifth embodiment)
Next, a power conversion system S according to a fifth embodiment of the present invention will be described with reference to FIG. In the present embodiment, the same components as those in the third embodiment (see FIG. 4) are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 6, the power conversion system S according to the present embodiment will be described in comparison with the power conversion system S according to the third embodiment (see FIG. 4), instead of the engine 13 (see FIG. 4). And a heat engine 130 is provided. The heat engine 130 in the present embodiment is not limited to the internal combustion engine as long as it generates heat of reaction between the supplied hydrogen and air and generates the power of the first generator 10. It is meant to include external combustion engines such as.

  Further, in the power conversion system S shown in FIG. 4, the booster pump P <b> 1 and the valve V <b> 1 are arranged between the first tank 7 and the separation device 2. In the power conversion system S according to the present embodiment, FIG. As shown, the valve V4, the fourth tank 27, the density meter 25, and the booster pump P1 are arranged in this order.

Further, in the power conversion system S shown in FIG. 4, the dehydrogenated product and undecomposed organic hydride separated from hydrogen by the separation device 2 are stored in the second tank 12, but in this embodiment, As shown in FIG. 6, the separation device 2 is connected to the fourth tank 27 and the second tank 12 via a valve V3 which is a three-way switching valve. That is, when the valve V3 is switched in the A direction, the separation device 2 and the fourth tank 27 communicate with each other, and when the valve V3 is switched in the B direction, the separation device 2 and the second tank 12 communicate with each other. ing.
The density meter 25 relatively measures the concentration of the organic hydride in the liquid filled in the fourth tank 27 according to the density of the liquid.
Incidentally, in the present invention, another densitometer can be used instead of the densitometer 25. As another densitometer, a known densitometer can be preferably used as long as it can measure the concentration of organic hydride. Specifically, for example, a device that measures the concentration of organic hydride by changing the dielectric constant is used. Can be mentioned.
In FIG. 6, reference numeral 26 denotes a liquid level meter that detects the liquid level (level) in the fourth tank 27.

  Further, the power conversion system S according to the present embodiment controls driving and stopping of the booster pump P1, switching of the flow path (A direction or B direction) of the valve V3, opening and closing of the valve V4, etc. in a predetermined procedure. Does not have a controller.

  Next, a procedure in which the above-described controller controls the booster pump P1, the valves V3 and V4 will be described while describing the operation of the power conversion system S according to the present embodiment. FIG. 7 is a time chart for explaining the timing of driving or stopping the booster pump P1, switching of the valve V3, and opening / closing of the valve V4. FIG. 8 is a flowchart showing a procedure in which the controller performs switching of the valve V3 and control of opening and closing of the valve V4.

  In the power conversion system S according to the present embodiment shown in FIG. 6, when a predetermined switch (not shown) is turned on and started, the operation of the heat engine 130 is started and the booster pump P1 is driven. Incidentally, when the power conversion system S is activated, the organic hydride until the tank capacity is reached is stored in the first tank 7 and the fourth tank 27. That is, the first tank 7 and the fourth tank 27 at the time of activation are so-called full. Further, the switching direction of the valve V3 at the start (initial state) is set to the A direction, and the valve V4 is in a closed state.

  Then, the heat engine 130 that has started operation burns air and the fuel supplied from the third tank 14 to generate power, generates power in the first generator 10, and generates the generated heat. It flows through the heat exchanger 5 and the hydrogen generator 1 through a predetermined heat medium. Thereby, the heat exchanger 5 and the hydrogen generator 1 are warmed up to a predetermined temperature.

  On the other hand, the driven booster pump P1 sends the organic hydride (liquid) in the fourth tank 27 to the expander 6 through the separation device 2 and the heat exchanger 5. That is, the organic hydride (liquid) pumped by the booster pump P1 is preheated by the separation device 2 and then becomes superheated steam (organic hydride gas) by the heat exchanger 5 as in the first embodiment. Then, power is generated by the expander 6. The expander 6 generates power with the second generator 11 using the generated power.

  The organic hydride sent from the expander 6 to the hydrogen generator 1 is decomposed into hydrogen and a dehydrogenated product, and a mixture of these hydrogen, dehydrogenated product, and undecomposed organic hydride is sent to the separation device 2. It is. Then, the hydrogen separated by the separation device 2 is supplied to the heat engine 130 and burned together with the fuel.

  In addition, when the switching direction of the valve V3 is set to the A direction, the undecomposed organic hydride and dehydrogenated product separated by the separation device 2 are returned to the fourth tank 27 and again the fourth tank. 27 is supplied toward the expander 6 side. Further, when the switching direction of the valve V3 is set to the B direction, the organic hydride and the dehydrogenated product from the separation device 2 are stored in the second tank 12.

Such switching operation of the valve V3 is controlled by the controller (not shown) together with the opening / closing operation of the valve V4.
Next, switching timing of the valve V3 and opening / closing timing of the valve V4 will be described with reference to FIG.

In FIG. 7, time t1 is when the power conversion system S according to the present embodiment is started, time t3 is when the valve V3 is switched from the A direction to the B direction, and time t4 is the valve V3. Is switched from the B direction to the A direction and the valve V4 is opened. Time t5 is when the valve V3 is switched from the A direction to the B direction again.
Time t2 is the time when the decomposition product of the organic hydride decomposed by the hydrogen generator 1 first reaches the fourth tank 27 after the power conversion system S is activated.

In FIG. 7, the liquid level (Lx) in the fourth tank 27 is a graph showing the transition of the liquid level (Lx) in the fourth tank 27 detected by the liquid level meter 26 shown in FIG. Is a tank capacity of the fourth tank 27, and Lt is a predetermined threshold value that defines a guideline of the lower limit of the liquid level in the fourth tank 27. Incidentally, the threshold value Lt can be set within a range of 5% to 50% of the tank capacity, but is not limited thereto.
In FIG. 7, the organic hydride concentration (Cx) in the liquid in the fourth tank 27 is calculated based on the liquid density detected by the density meter 25 shown in FIG. Cm is equal to the concentration of organic hydride stored in the first tank 7, and Ct is a measure of the lower limit of the concentration of organic hydride in the fourth tank 27. It is a predetermined threshold value to be defined. This threshold value (Ct) may be defined by the concentration of the organic hydride at which the hydrogen obtained by the decomposition of the organic hydride in the hydrogen generator 1 is almost lost or the amount of hydrogen to be supplied to the heat engine 130 is insufficient. For example, it can be set within the range of more than 0 mass% and 10 mass% or less, but is not limited thereto.

In the power conversion system S according to the present embodiment, as shown in FIG. 7, before the start-up, the booster pump P1 is in a stopped state, and the switching direction of the valve V3 is the A direction, that is, the separation shown in FIG. It is set in a direction from the device 2 toward the fourth tank 27 side, and is set so that the valve V4 is closed.
And in the 4th tank 27 before starting by power conversion system S concerning this embodiment, organic hydride with concentration Cm is full (liquid level Lm). That is, the liquid level (Lx) is Lm until time t1.

  First, when the power conversion system S is activated (time t1), the booster pump P1 is driven and the organic hydride in the fourth tank 27 is supplied toward the expander 6 (see FIG. 6). At this time, since the separator 2, the heat exchanger 5, and the hydrogen generator 1 are warming up, there is almost no return of organic hydride and decomposition products from the separator 2 to the fourth tank 27, and the fourth tank. The liquid level (Lx) in 27 gradually decreases as the organic hydride is supplied to the expander 6 (see FIG. 6).

  Thereafter, when the warming-up of the separator 2, the heat exchanger 5, and the hydrogen generator 1 is completed, and the organic hydride and its decomposition product (dehydrogenated product) start to return from the separator 2 (time t2), the fourth tank The concentration (Cx) of the organic hydride in 27 is gradually reduced as it is diluted with the dehydrogenated product.

  When the time t2 has elapsed, the organic hydride and the dehydrogenated product flow into the fourth tank 27 from the separator 2 (see FIG. 6), while the organic equivalent of the hydrogen equivalent supplied from the separator 2 toward the heat engine 130 As the hydride is consumed, the liquid level (Lx) in the fourth tank 27 gradually decreases.

Then, when the concentration (Cx) of the organic hydride in the liquid in the fourth tank 27 becomes equal to or less than the threshold value (Ct) (time t3), the concentration (Cx) in the fourth tank 27 is reduced to hydrogen by the hydrogen generator 1. As a result, the valve V3 is switched from the A direction to the B direction. That is, the organic hydride and dehydrogenated product from the separation device 2 are sent to the second tank 12 (see FIG. 6).
At this time, since the organic hydride and dehydrogenated product are not returned from the separation device 2 to the fourth tank 27, the liquid level (Lx) in the fourth tank 27 is the organic hydride to the expander 6 (see FIG. 6) side. And gradually decreases with the supply of the dehydrogenated product.

  Then, when the liquid level (Lx) in the fourth tank 27 becomes equal to or less than the threshold value (Lt) (time t4), the valve V3 is switched from the B direction to the A direction. That is, the valve V3 is switched so that the organic hydride and dehydrogenated product from the separation device 2 are sent into the fourth tank 27 (see FIG. 6). At the same time, the valve V4 is opened. There is no change in the concentration (Cx) of the organic hydride in the fourth tank 27 from time t3 to time t4.

Then, after the elapse of time t4, the valve V4 is opened, so that organic hydride is supplied from the first tank 7 toward the fourth tank 27, and the liquid level (Lx) of the fourth tank 27 rises. At the same time, the concentration (Cx) of the organic hydride in the fourth tank 27 also increases.
Thereafter, when the liquid level (Lx) of the fourth tank 27 becomes Lm (the fourth tank 27 is full) (time 5), the valve V4 is closed.
After the elapse of time t5, the liquid level (Lx) in the fourth tank 27 is gradually lowered due to the consumption of the organic hydride by supplying hydrogen to the heat engine 130, and returns from the separation device 2. Due to the dehydrogenated product, the concentration (Cx) of the organic hydride in the fourth tank 27 decreases again.

  As described above, in the power conversion system S according to the present embodiment, until the concentration (Cx) of the organic hydride in the fourth tank 27 is equal to or lower than the predetermined concentration (threshold value (Ct)), The organic hydride (dehydrogenated product) is circulated so as to circulate between the expanders 6 and when the concentration (Cx) becomes a predetermined concentration (threshold (Ct)) or less, the circulating organic hydride (dehydrogenation) Is collected in the second tank 12 and the fourth tank 27 is supplemented with a shortage of organic hydride from the first tank 7.

  Next, a procedure in which the controller (not shown) of the power conversion system S according to the present embodiment performs switching of the valve V3 and control of opening and closing of the valve V4 will be described with reference to the flowchart of FIG.

In the power conversion system S (see FIG. 6) according to the present embodiment, when a predetermined switch is turned on and the heat engine 130 (see FIG. 6) starts operation, the booster pump P1 (see FIG. 6) is driven at that time. . This timing corresponds to time t1 in FIG.
As shown in FIG. 8, the initial state of the valve V3 (see FIG. 6) is set to the direction A (see FIG. 6), and the initial state of the valve V3 (see FIG. 6) is closed. Set to state.

First, the controller (not shown) of the power conversion system S calculates the concentration (Cx) based on the detection signal of the density meter 25 (see FIG. 6), and whether the concentration (Cx) is equal to or less than the threshold value (Ct). Is determined (step S101). When it is determined that the density (Cx) exceeds the threshold value (Ct) (No in step S101), step S101 is repeated.
When it is determined that the concentration (Cx) is equal to or less than the threshold value (Ct) (Yes in step S101), the valve V3 is switched in the B direction (step S102).
This timing corresponds to time t3 in FIG.

Next, the controller (not shown) of the power conversion system S determines whether or not the liquid level (Lx) is equal to or lower than the threshold value (Lt) based on the detection signal of the liquid level gauge 26 (see FIG. 6) (step) S103). When it is determined that the liquid level (Lx) exceeds the threshold value (Lt) (No in step S103), step S103 is repeated.
When it is determined that the liquid level (Lx) is equal to or lower than the threshold value (Lt) (Yes in step S103), the valve V3 is switched to the A direction (step S104), and the valve V4 is opened (step S104). S105).
This timing corresponds to time t4 in FIG.

Next, the controller (not shown) of the power conversion system S determines whether or not the liquid level (Lx) has reached the tank capacity (Lm) based on the detection signal of the liquid level gauge 26 (see FIG. 6). (Step S106). When it is determined that the liquid level (Lx) has not reached the tank capacity (Lm) (No in step S106), step S106 is repeated.
When it is determined that the liquid level (Lx) has reached the tank capacity (Lm) (Yes in step S103), the valve V4 is closed (step S107).
This timing corresponds to time t5 in FIG.

  In this way, the power conversion system S is generated by the power generated by the superheated steam of the organic hydride and the decomposition of the organic hydride while continuously monitoring the concentration (Cx) of the organic hydride by such a controller (not shown). It is configured to obtain power from a heat engine using hydrogen as a fuel.

  According to the power conversion system S according to the present embodiment as described above, the same operational effects as those of the power conversion system S according to the third embodiment (see FIG. 4) can be obtained. Can play.

  According to the power conversion system S according to the present embodiment, the organic hydride (dehydrogenated product) is circulated so as to circulate between the fourth tank 27 and the expander 6, and the hydrogen generator 1 performs organicity in the middle thereof. Hydrogen is generated from hydride. As a result, hydrogen can be generated from the organic hydride with high efficiency.

  Further, according to the power conversion system S according to the present embodiment, the amount of the gas medium (organic hydride and dehydrogenated product) supplied to the expander 6 is set without depending on the amount of hydrogen generated by the hydrogen generator 1. can do. That is, in the power conversion system S (see FIG. 4) according to the third embodiment, when the amount of organic hydride supplied to the expander 6 is determined, the maximum amount of hydrogen generated by the hydrogen generator 1 is stoichiometric. Will be decided. On the other hand, according to the power conversion system S according to the present embodiment, the gas medium circulated between the fourth tank 27 and the expander 6 can be a mixture of organic hydride and dehydrogenated product. Conditions are set so that the amount of hydrogen generated in the hydrogen generator 1 (see FIG. 6) in the present embodiment is the same as the amount of hydrogen generated in the hydrogen generator 1 (see FIG. 4) in the third embodiment. When set, the amount of the gas medium (organic hydride and dehydrogenated product) supplied to the expander 6 in this embodiment is the same as the gas medium (organic hydride) supplied to the expander 6 in the third embodiment. ) Will be more than the amount. As a result, according to the power conversion system S according to the present embodiment, greater power can be obtained than the power conversion system S according to the third embodiment.

DESCRIPTION OF SYMBOLS 1 Hydrogen generator 2 Separating device 3 1st expander 4 Power converter 5 Heat exchanger 6 2nd expander 7 1st tank 8 Hydrogen combustion apparatus 9 Compressor 10 1st generator 11 2nd generator 12 2nd tank 13 Engine (Internal combustion engine)
DESCRIPTION OF SYMBOLS 20 Expander type hydrogen generator 14 Engine 15 Preheating device 17 Radiator 18 Circulation path 19 2nd heat exchanger 25 Density meter 26 Liquid level meter 27 4th tank 130 Heat engine S Power conversion system

Claims (7)

A hydrogen generator for heating the supplied organic hydride in the presence of a predetermined catalyst to produce hydrogen and a dehydrogenated product of the organic hydride;
A separation device that separates hydrogen obtained from the hydrogen generator and a dehydrogenated product of organic hydride and sends out hydrogen;
A power conversion device that obtains power by burning hydrogen delivered from the separation device;
A heat exchanger that performs heat exchange between the exhaust gas discharged from the power converter and the organic hydride before being supplied to the hydrogen generator;
An expander that generates power with organic hydride that has become superheated steam by heat exchange in the heat exchanger and sends the organic hydride to the hydrogen generator;
A power conversion system comprising: The power conversion system according to claim 1,
The power conversion system, wherein the expander forms an expander-type hydrogen generator integrally with the hydrogen generator. In the power conversion system according to claim 1 or 2,
The organic hydride before being supplied to the heat exchanger flows through the separation device, and the organic hydride exchanges heat with hydrogen and a dehydrogenated product of the organic hydride in the separation device, and then the heat exchanger. Power conversion system characterized by being supplied to The power conversion system according to any one of claims 1 to 3,
The power conversion device comprises a hydrogen combustion device for combusting hydrogen delivered from the separation device;
A compressor for compressing the air supplied to the hydrogen combustion device;
An expander that generates power by hydrogen combustion gas from the hydrogen combustion device;
A power conversion system comprising: In the power conversion system according to any one of claims 1 to 4,
The hydrogen generation apparatus heats an organic hydride with exhaust gas discharged from the power conversion apparatus. A hydrogen generator for heating the supplied organic hydride in the presence of a predetermined catalyst to produce hydrogen and a dehydrogenated product of the organic hydride;
A separation device that separates hydrogen obtained from the hydrogen generator and a dehydrogenated product of organic hydride and sends out hydrogen;
An internal combustion engine that obtains power by burning fuel containing hydrogen delivered from the separator;
A first heat exchanger that exchanges heat between the exhaust gas discharged from the internal combustion engine and the organic hydride before being supplied to the hydrogen generator;
A second heat exchanger that preheats the organic hydride supplied to the first heat exchanger by heat exchange between the organic hydride before being supplied to the first heat exchanger and the cooling water sent from the internal combustion engine;
An expander that generates power with organic hydride that has become superheated steam by heat exchange in the first heat exchanger and sends the organic hydride to the hydrogen generator;
A power conversion system comprising: The power conversion system according to claim 6, wherein
The organic hydride supplied from the second heat exchanger to the first heat exchanger flows through the separation device before being supplied to the first heat exchanger, and hydrogen and hydrogen in the separation device are supplied. A power conversion system, wherein the power conversion system is further preheated by heat exchange with a dehydrogenated product of an organic hydride and then supplied to the first heat exchanger.

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