JPS597032B2 - How to convert thermal energy into mechanical energy - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of converting thermal energy into mechanical energy, and more specifically, the present invention relates to a method of converting thermal energy into mechanical energy, and more specifically, it utilizes a reversible reaction between a metal and hydrogen to convert hydrogen by heating a metal hydride in a sealed container. The present invention relates to a method for generating hydrogen, absorbing hydrogen by cooling a metal corresponding to the metal hydride in a sealed container, and driving a piston, a turbine, etc. using the pressure difference between the two containers.

In the case of thermal power generation using water as a medium, fuel such as LNG or naphtha is usually burned at 1500° C. to heat a boiler to obtain steam at about 566° C., which is used to drive a turbine.

Even though the combustion temperature is 1500℃, it is actually used at a lower temperature of 566℃.
Temperature between 1500℃ and 566℃ of boiler? It is used only for conduction, reducing efficiency unnecessarily.

The present inventors have already proposed a technology for converting thermal energy into mechanical energy using metal hydrides as a non-polluting fuel engine (Japanese Patent Application No. 51-89 074, 53-53
355, 53-53356).

In this heat engine a liquid can be used as the heating medium and there is no large temperature drop between the heating medium and the conversion system as in boilers.

Furthermore, the use of metallic hydrogen {lm) brings many advantages, such as the ability to obtain a large pressure difference from a small temperature difference and the ability to utilize low-quality waste heat.

For example, in the case of L a N i 5 H 6, its equilibrium hydrogen pressure is 2.2 atm at 20°C, but it is 230 atm at 200°C and 2300 atm at 400°C.
, 6900 atm at 566°C.

However, from the standpoint of device safety, the practical limit is about 50 atm of hydrogen pressure, and LaNi
In case of H, 120°C is the maximum operating temperature of the heating medium.

In reality, when waste heat from a factory is used as a heating medium hot liquid, the waste heat may be 300°C or 600°C, so temperatures between 120°C and 120°C are wasted.
Efficiency decreases.

On the other hand, for example, in the case of M g 2 N i N4, 450
℃ and 250 ℃, and a temperature difference between 250 ℃ and 150 ℃ is not available when using sea water as the cooling medium.

The present inventors have conducted intensive research to develop a system that can efficiently convert heat into mechanical energy by making full use of the large temperature difference, such as that between relatively high-temperature factory waste heat and seawater. have found that this task can be achieved by using two or more metal hydrides that exhibit equal equilibrated hydrogen pressures at different temperatures.

According to the present invention, n types (n is an integer of 2 or more) of metal hydrides, each having a different temperature T , T
,●●●Tn, which show l2 equilibrium hydrogen pressure PH that is almost equal to each other, and n different temperatures t1, t2●●●tn (however, T〉t ≧T
Metal hydrides exhibiting nearly equal equilibrium hydrogen pressures P C (where PH>L PL) with Each metal hydride is housed separately in a first reaction chamber group consisting of T1 and T2 using a heating medium.
...●Tn is maintained to generate hydrogen pressure PH in each reaction chamber of the first reaction chamber group, and the reaction chambers of the first reaction chamber group are connected in parallel to each other, and the n corresponding to the metal hydride is Different types of dehydrogenation metals are stored separately in a second reaction chamber group consisting of n reaction chambers, and each dehydrogenation metal is heated to a temperature of t1, t2, ●, or t using a cooling medium.
By keeping the temperature n, when each reaction chamber of the second reaction chamber group receives hydrogen, it is possible to absorb hydrogen and exhibit hydrogen pressure PL, and the reaction chambers of the second reaction chamber group are arranged in parallel with each other. At this time, the temperature is 1. 1...●tn
-1, the refrigerant used for cooling at temperature T2, T3 s...
The above-mentioned first
A method for converting thermal energy into mechanical energy is provided, characterized in that the reaction chambers are driven by applying a pressure difference PH-PL between the second reaction chamber group and the second reaction chamber group.

The present invention will be explained in detail below with reference to the drawings.

FIG. 1 is an explanatory diagram of the principle of the thermal-mechanical energy conversion system according to the present invention, in which metal hydride MA HX s
An example using three types of MB H y and MC Hz will be shown.

MAHX/I'i indicates equilibrium hydrogen pressure PH and PL at temperatures T and t1, respectively, and MBHY represents temperature T2 and t2.
denote the equilibrium hydrogen pressure of PH and PL, respectively, and MOH
z is the equilibrium hydrogen pressure P at temperatures T3 and t3, respectively.
A metal hydride exhibiting H and PL, in which case T1>
It is appropriately selected so that the relationship t1≧T2 ''> j 2≧T3 > t3 holds true.

These metal hydrides are each placed in a sealed reaction chamber R s R
3 * Housed in R5.

R2 s R4tR6 PA MAHX-MBHy sMC
Dehydrogenation metal M A*MB corresponding to Hz,
This is a sealed reaction chamber containing MO.

The reaction chambers R, R3, and R5 are connected in parallel to each other and connected to the switching valve 2 by a royal transmission pipe 1, while the reaction chamber R2
s R4 *R6 are also connected in parallel to each other,
It is connected to the switching valve 2 by a pressure transmission pipe 3.

The switching valve 2 is used to alternately connect the reaction chamber groups Rs R3 s R5 and the reaction chamber groups R2 s R4 s R6 to a mechanical energy generating means generally indicated by 4.

In the illustrated example, the mechanical energy generating means is a combination of a piston and a flywheel? used.

That is, the switching valve 2 is communicated with a piston cylinder 5, the piston 6 is connected to a flywheel 7 via a crankshaft 8, and the flywheel 7 is driven by the reciprocating movement of the piston 6.

Note that the switching valve 2/I''i is not shown.

The switching operation is performed by means for detecting the top and bottom dead center positions of the piston.

That is, when the piston 6 reaches the top and bottom dead centers, the detection means detects this, and according to the output thereof, the switching valve is operated, and the reaction chamber group R1 s R 3 x R 5 or R
2*R4 x R6 are communicated with the piston cylinder 5.

Now, the reaction chamber R is heated by a high temperature heat source (for example, factory waste heat) having a temperature TH, and MAHX is maintained at a temperature T1.

As a result, MAHX absorbs the amount of heat Q1, 22 -MAHX→-MA+H2 XX A reaction occurs and hydrogen pressure of PH is generated.

On the other hand, reaction chamber R2 is cooled by the medium in heat storage tank 9 having temperature TA, and MA is maintained at temperature t.

As a result, MA. In the presence of hydrogen at a pressure of PH, it releases heat Q2, causing the reaction 2 - MA + H2 → - MAHX Heated by the heat medium in the heat storage tank 9, MBH
Y is maintained at temperature T2.

Then, when it absorbs the amount of heat Q'2 and becomes MB, a hydrogen pressure of PH is generated.

On the other hand, the reaction chamber R4 is cooled by a medium having a temperature TB in the heat storage tank 10 and is maintained at the MBH temperature t2, and under the hydrogen pressure of PH, it releases the heat amount Q3 and absorbs the hydrogen pressure corresponding to PH-PL. can do.

In addition, the reaction chamber R5 is heated by the medium in the heat storage tank 10, and the MOHZ is maintained at the temperature T3, absorbs the amount of heat Q'3, and is heated by the medium in the heat storage tank 10.
C and Nashi generate hydrogen pressure of PH.

The reaction chamber R6 is cooled by a heat source (for example, seawater) having a temperature TL, and Mc is maintained at a temperature t3, and under the hydrogen pressure of PH, it releases a heat amount Q4 and becomes McHZ, which is hydrogen corresponding to PH-PL. Can absorb pressure.

Furthermore, if a metal hydride is used such that T2=t1 and T3=t2≦ and the medium of the heat storage tanks 9 and 10 is liquid, then T2=t=TA and T3=t2=TB.
It is.

In this case Q2 = Qi, Q3? Q3′ and heat storage tank 9,
By improving the insulation of 10, the medium can be maintained at a temperature of TA s T B, respectively, without external heating or cooling.

By controlling the temperature of the metal hydride and metal as described above, the metal hydride M A H x s MBHy
The temperature at which sMCHZ is heated is T s T2 s T
Even if the pressure is different as shown in 3, the pressure of hydrogen generated is all PH.
The reaction chambers R1 s R2 s R3 can be connected in parallel.

Still metal M A t M B s MC can be linked.

Further, even if the metal M A I M B sMC is cooled at different temperatures t, t2, and t3, the hydrogen pressure it can absorb is the same, and the reaction chambers R2, R4, and R6 can be connected in parallel.

A system configured as described above for converting force energy into mechanical energy is operated as follows.

When the piston 6 is at the top dead center as shown by the solid line in the figure, if the switching valve 2 is in a position to communicate the reaction chambers R, R2, R3 (first reaction chamber group) with the piston cylinder 5, the first
The pressure PH generated in the reaction chamber group is transmitted into the cylinder and causes the piston 6 to descend.

When the piston 6 reaches the bottom dead center as shown by the dotted line in the figure, the switching valve 2 is switched to connect the reaction chambers R2, sR4, sR6 (second reaction chamber group) and the piston cylinder 5. It is absorbed by the metal in the reaction chamber group, and the pressure inside the cylinder drops to PL, and as a result, the piston 6 rises.

In this way, by alternately communicating the piston cylinder 5 with the first and second reaction chamber groups by the switching valve 2,
The piston performs a reciprocating motion so that the flywheel 7 can be driven.

According to the present invention, by simply applying heat from a heat source at temperature TH to reaction chamber R1, the heat is transferred one after another in a cascade manner to R3 sR.
After being used for heating R2*R4 of 5 and cooling, the temperature T
The entire temperature difference between TH and TL can be effectively converted into mechanical energy.

The system for converting thermal energy into mechanical energy as described above is such that the metal hydride in the first reaction chamber group has completed its reaction and can no longer exhibit hydrogen pressure PH, and/or the metal in the second reaction chamber group has After completing the hydrogen absorption reaction, the hydrogen pressure P
The operation is continued until L can no longer be exhibited (that is, until the pressure difference between the first reaction chamber group and the second reaction chamber group disappears).

After that, the reaction chamber R1 is set to t2, R2 is set to T, R3 is set to t2, R4 is set to T2, R5 is set to t3, and R6 is set to T3.
If the temperature control is changed to maintain each of the reaction chamber R
2* R4 sR6 is hydrogen generation side, reaction chamber R* R 3
s R 5 operates as a hydrogen absorption side.

However, in reality, it takes time to reach the specified temperature, and mechanical energy cannot be extracted during that time.

Therefore, in order to operate continuously for a long time, we prepared another set of conversion systems as described above, and while one reacted, the other was preheated or precooled to eliminate the pressure difference. What is necessary is to repeatedly switch to the other mode.

Figure 2 i, ii, iii, iv shows a method of continuously generating electrical energy using a turbine and a dynamo from a high temperature heat source T1 and a low temperature heat source T4 using two sets of the above energy conversion systems over time. This is what is shown.

In FIG. 2, a turbine and a dynamo driven by hydrogen gas are located in the center, solid lines indicate water conduits, and arrows indicate the direction of gas flow.

The system on the left side of the diagram is connected to the turbine and is in operation, while the system on the right side is in the preheating stage.

In the system on the left, the heating medium from the high-temperature heat source T1 passes through the reaction chamber containing DMAHx through the double line indicated by T1.
The reaction heat Q1 is given while maintaining the temperature at .

The generated high-pressure hydrogen with PH is led to the siturbine through the conduit shown by the arrow, and returned to the reaction chamber containing the MA held at T2.

MA absorbs hydrogen gas from PL at T2 and generates heat at Q2.

The heat medium from the heat storage tank T2 is also circulating through the reaction chamber containing MBHY at the same time, giving heat Q2 to MBHY and generating high pressure hydrogen of PH.

This hydrogen is mixed and directed to the turbine as it is equal to the pressure of the hydrogen from the MAHX.

In this way, the heat of Q1 from the high temperature heat source is converted into mechanical energy while moving inside the system, and finally the remaining heat of Q is released to the low temperature heat source of T4.

The maximum conversion efficiency obtained at this time is Carnot's T1-T
4 From the equation, it is the factor of x100.

T1 The hydrogen conduit shown in the diagram on the right is separated from the turbine and dynamo by two valves, and each reactor vessel is connected to a heat transfer medium from the hot crack source T1, the heat storage tanks T2 and T3, and the cold heat source T4. They are preheated and preheated to their respective temperatures and are waiting until the reaction in the left system is completed.

In this case, since reaction heat is not required, there are no arrows indicating the flow of heat in the heat medium flow path and no arrows indicating the flow of hydrogen gas.

FIG. 2 11 shows a state in which the conversion system on the left side has completed its reaction and is separated from the turbine and is being preheated and precooled, while the turbine is being driven by the system on the right side.

Further, this conversion cycle is completed through steps iii and iv in FIG. 2, and the process returns to FIG. 2 1 again.

Using this system, it is possible to increase mechanical energy or electrical energy over a long period of time without consuming any parts as long as there is a high temperature heat source of T1 and a low temperature heat source of T4.

Although the method of the present invention has been described above with respect to an example using three types of metal hydrides, two, four or more types of metal hydrides and their corresponding metals can be used.

The type and number of metal hydrides actually used can be appropriately determined based on the Arrhenius plot (relationship between temperature (reciprocal of absolute temperature and equilibrium hydrogen pressure (logarithm)) of various metal hydrides.

That is, it may be determined as appropriate, taking into consideration the heat source temperature (TH and TL), efficiency, and required PH-PL value.

For example, when using two types of metal hydrides, the one on the high temperature side (MA HX) is Mg2 NiH4.
+TI COHsZrMn2H2CaNi5 H6 etc., but as for the low temperature side (MBH y), C
a Ni5 H6 sLaNi5H6 s Fe
T ] Hz T iMn15 H2 *L a C
Examples include 05 H3, and it is best to choose an appropriate one from each.

Further, as an example of using three types of metal hydrides, Mg 2 Ni H 4 * Mg C as a high temperature MAHX
TiCoH as MBHY for medium temperature such as u2 H2
sZrMn2H2sLaCo5H3 sPdH, etc.
and C a N i5 H4sN as McHZ for low temperature
i5 H 51TiMn15H25* FeTiH,
LaNi5 H6, etc. can be used and used in appropriate combination.

In addition, in the above explanation, the reaction chamber is fixed and a jacket or the like is provided to circulate the heat or cooling medium to control the temperature. However, the present invention is not limited to this. It's okay.

Furthermore? The mechanical energy generating means is not limited to a piston, but any means that can be driven using a pressure difference as a drive source can be used.

Example sealed pressure container R 1 s R 3 s R5 M
g 2 N i H 41557, TiCoH166f
, and L a N i 5 H 67101 are crushed and housed in a sealed pressure-resistant container R 2 s R 4 s
MgNi 150g, TiCo160 for R6
f, and LaNj5 7 0 0? Each was contained in fine powder.

Container R1 was placed in a sodium nitrate salt bath at 450°C, containers R2 and R3 were placed in a 250°C oil bath, containers R4 and R5 were placed in a 130°C oil bath, and container R6 was placed in a 15°C oil bath. Each was immersed in water.

Containers R, R3, R5 are connected in parallel with each other, while containers R2, R4, R6 are connected in parallel with each other, and each set is connected to a piston with a diameter of 20 mm through a switching valve as shown in FIG. The cylinders were alternately communicated with each other to drive the pistons.

A DC motor was connected to the flywheel to drive it.

R1 * R3 s The hydrogen pressure on the R5 side is 4 8 a
tm % R2 * R4 s Hydrogen pressure on R6 side is 2
It was an ATM.

The theoretical conversion efficiency at this time was 60.1 times, and the conversion efficiency obtained in this example was 28 times.

[Brief explanation of the drawing]

FIG. 1 is a diagram illustrating the principle of an apparatus for carrying out the method of the present invention, and FIG. 2 is an illustration of an apparatus for continuously carrying out the method of the present invention. R1 to R6... Reaction chamber, 2... Switching valve, 5... Piston cylinder, 6... Piston, 7... Flywheel, 9, 10... Heat storage tank, 12... Switching valve .

Claims (1)

[Scope of Claims] 1 n types of metal hydrides (n is an integer of 2 or more), each exhibiting approximately the same equilibrium hydrogen pressure PH at different n types of temperatures T1, T2.●●Tn. , and n different temperatures t1, t2...tn (however, T1
) j 'i≧T2≧t2...t n - t≧T
n > tn) and the equilibrium hydrogen pressures PL are approximately equal to each other.
(however, PH>PL), a metal hydride with n
Each metal hydride in the first reaction chamber group is housed separately in a first reaction chamber group consisting of sealed reaction chambers, and each metal hydride in the first reaction chamber group is kept at a temperature of T1, T2s...Tn using a heat medium. While generating hydrogen pressure PH in the reaction chamber,
The anti-seed chambers of the first reaction chamber group are connected in parallel to each other, and the front? n types of dehydrogenation metals corresponding to metal hydrides respectively
The dehydrogenation metals are individually housed in a second reaction chamber group consisting of two reaction chambers, and each dehydrogenation metal is heated to a temperature t using a cooling medium.
, t2 ... tn, when each reaction chamber of the second reaction chamber group receives hydrogen, it is possible to absorb hydrogen and exhibit hydrogen pressure PL, and the reaction of the second reaction chamber group is The chambers are connected in parallel with each other, at temperatures t,
Mechanical energy generating means that can move using a pressure difference as a driving source, using the cooling medium used for cooling at t2...tn-1 as a heating medium for heating at temperatures T2 t T3 *...Tn, respectively. A method for converting thermal energy into mechanical energy, characterized in that the first and second reaction chamber groups are driven once by applying a pressure difference PH-PL between the first and second reaction chamber groups. 2. The fore-fertilization mechanical energy generating means includes a piston, a piston cylinder, a turbine, etc., and the inside of the piston cylinder or the turbine is
2. The method of claim 1, wherein the reaction chambers are driven by being alternately communicated with the groups of reaction chambers.