JPH0792294B2 - Heat pump method using hydrogen storage alloy - Google Patents

Description

TECHNICAL FIELD The present invention relates to a continuous heat pump method excellent in heat recovery performance by a flow and transfer method of a hydrogen storage alloy.

"Prior art" A conventional heat pump method using a hydrogen storage alloy is usually to fill a crushed hydrogen storage alloy into a container and cause the reaction in a fixed bed state, and to switch a plurality of containers alternately. Is. (For example, Japanese Showa 58
-19956, JP-A-60-101398, reference) "Problems to be solved by the invention" The conventional method not only increases the amount of hydrogen storage alloy used because of a plurality of fixed-layer containers, Since one container is used for occlusion and release, that is, for heat generation and cooling, sensible heat loss occurs in the container metal and alloy due to switching, and a decrease in heat utilization efficiency cannot be avoided. Also, powdery hydrogen storage alloys, especially those pulverized by activation, have extremely low thermal conductivity, so the heat exchanger heat transfer area of the reactor becomes large, a filter is required, and further hydrogen storage The equipment cost is generally high due to measures such as expansion of the alloy due to hydrogen absorption and the need for complicated instrumentation equipment to alternately use a plurality of vessels. This was one of the reasons why the heat pump method using hydrogen storage alloy was not put into practical use.

[Means for Solving the Problem] In order to solve the above problems, the present invention adopts a method of using a fluidized bed and a moving bed reactor instead of a conventional fixed bed, and adopts a first type hydrogen storage alloy (operating temperature range). In which the hydrogen equilibrium decomposition pressure is high, for example
High pressure side reactor 2 group using M _m NiAl alloy) (1A, 1B)
And a fluidized bed (1A, 2 sets of two low pressure side reactors (2A, 2B) using a second type hydrogen storage alloy (those having a low hydrogen equilibrium decomposition pressure in the operating temperature range, for example, LaNiAl alloy) 2A) Using a moving bed (1B, 2B) type reaction vessel, by circulating the release hydrogen gas, hydrogen is absorbed by the fluidized bed reaction (in 1A, 2A), and hydrogen is released by the moving bed reaction (1B, 2B).
(Inside), the hydrogen storage alloy after the reaction is circulated and moved between reactors 1A and 1B and between reactors 2A and 2B by using hydrogen as a carrier gas, and at the same time, high pressure side reactor 1B and low pressure side reactor 2B. The waste heat source is supplied to the high pressure side reactor 1A to cool it, and the high temperature heat output from the low pressure side reactor 2A is continuously obtained, or the waste heat source is supplied to the low pressure side reactor 2B and the high pressure side is supplied. Cool reactor 1A and low pressure side reactor 2A, and high pressure side reactor 1B
A method for continuously obtaining a cold heat output, which efficiently and continuously obtains high heat or cold heat without switching the reaction vessel.

Example 1 An example of the present invention will be described in detail below with reference to the drawings in the case of a temperature rising heat pump that obtains steam by using warm wastewater.

In Fig. 1, 1A of the high pressure side reactor is a fluidized bed type and 1B is a moving bed type, and each is filled with a first type hydrogen storage alloy having a high hydrogen equilibrium decomposition pressure (for example, M _m NiAl alloy). .
Similarly, 2A of the fluidized bed type low pressure side reactor is a fluidized bed type, 2B is a moving bed type, and each is filled with a second type hydrogen storage alloy having a low hydrogen equilibrium decomposition pressure (for example, LaNiAl type alloy). It Inside each reactor, MH heat exchangers (hereinafter referred to as heat exchangers of hydrogen storage alloy and heat medium) 10, 11, 12 and 13 are provided, and reactors 1A and 2A are provided with a fluidized bed 3. Further, the alloy separator 6 is made so that the hydrogen-absorbing alloy powder is easily moved by its own weight.
It is placed higher than 1B and 2B, and lower than 1B and 2B in 1A and 2A.

The first-class hydrogen storage alloy that has occluded hydrogen in the reactor 1A and moved through the alloy separator 6 is heated in the moving bed reactor 1B through the MH heat exchanger 11 through a warm waste water heat source of around 80 ° C. It On the other hand, the reaction residual hydrogen gas (hereinafter referred to as residual hydrogen carrier gas) flowing out from the fluidized bed reactor 2A is pressurized by the booster 4 and fed from below the reactor 1B. The rich hydrogen storage alloy in 1B (referred to as a hydrogen storage alloy that has stored hydrogen) contacts the heat transfer tube of the MH heat exchanger 11 while moving down, and receives heat to release hydrogen. The released hydrogen gas (hereinafter, the hydrogen gas released from the rich hydrogen storage alloy is referred to as a rich hydrogen carrier gas) has its alloy powder removed by an alloy catcher 7, passes through a gas heat exchanger 9, and exchanges heat with the residual hydrogen carrier gas. Then, the mixture is heated and is directly sent to the fluidized bed reactor 2A of the low pressure side reactor due to the pressure difference. At this time, when saturated hot water of 120 ° C. is supplied to the MH heat exchanger 12 of 2 A, the hydrogen-absorbing alloy that is fluidized and floating on the fluidized bed in the reactor reacts with the fed hydrogen and absorbs some hydrogen to generate heat. Built-in heat exchanger Gives heat to the hot water in the heat transfer tube. As a result, saturated hot water becomes steam at 120 ° C.

The residual hydrogen carrier gas discharged from the reactor 2A is trapped in the alloy powder in the gas by the alloy separator 6, exchanges heat with the rich hydrogen carrier gas in the gas heat exchanger 9, and is boosted to the original high pressure side reactor 1B. After being fed by the machine 4 to release hydrogen by the moving bed reaction, it again serves as a fluidizing gas. In this way, hydrogen gas is continuously recycled between 1B and 2A. Similarly, when a warm wastewater heat source of around 80 ° C is supplied to the MH heat exchanger 13 of the moving bed type reactor 2B of the low pressure side reactor filled with the second type hydrogen storage alloy, the hydrogen storage alloy moves down in the reactor. It passes through a heat exchanger and is heated by hot wastewater to release hydrogen. The rich hydrogen carrier gas is removed of alloy powder in the gas by the alloy catcher 7, passes through the gas heat exchanger 8, and is supplied to the fluidized bed reactor 1A of the high pressure side reactor at a differential pressure. At this time, cooling water is passed through the 1A MH heat exchanger 10 to cool it. The hydrogen storage alloy is suspended and fluidized by the rich hydrogen carrier gas in 1 A to store hydrogen, and is discharged from the upper part together with the residual hydrogen carrier gas. The accompanying hydrogen-absorbing alloy powder is collected by the alloy separator 6, and the residual hydrogen carrier gas is boosted by the booster 5 through the gas heat exchanger 8 and is boosted to 2B of the low pressure side reactor by the moving transport reaction. After releasing hydrogen, it becomes a fluidizing gas again. That is, hydrogen gas is continuously recycled between 1A and 2B.

It should be noted that as for hydrogen, an amount equivalent to the amount of carrier gas is first filled and used, and thereafter, replenishment of hydrogen from outside the system is not required.
In this method, the residual gas hydrogen carrier gas amount flowing out from 1A, 2A is extremely small compared to the rich hydrogen carrier gas amount released from 1B, 2B, but 1A, 2A is a fluidized bed reaction, while 1B, Since 2B is a moving bed reaction, the hydrogen cycle can avoid an operational imbalance. However, it is necessary to optimally design the inner diameter, length, and structure of each fluidized bed type and moving bed type reactor so that the residence time in the container required for the reaction between the hydrogen storage alloy and hydrogen is appropriate. .

On the other hand, the alloy powder is collected by the alloy separator 6 and moved by the feeder 14 to the reactors 1B and 2B by its own weight. The hydrogen storage alloy that has released hydrogen in 1B and 2B moves to 1A and 2A by its own weight by the feeder 15. That is, the first type hydrogen storage alloy is continuously moved and circulated between the reactors 1A and 1B, and the second type hydrogen storage alloy is repeatedly stored and released of hydrogen between the reactors 2A and 2B. .

The above operation will be described with reference to the cycle diagram of FIG. The horizontal axis is the reciprocal of the absolute temperature T, and the vertical axis is the logarithm of the hydrogen equilibrium decomposition pressure P of the hydrogen storage alloy. The cycle point numbers correspond to the reactor numbers in FIG. Pour warm wastewater of 80 ℃ into 1B and 2A
When saturated hot water of 120 ℃ is flown into the tank, each hydrogen equilibrium decomposition pressure has a pressure drop of 1B> 2A, and hydrogen flows to 1B or 2A
Then, steam is generated by an exothermic reaction due to hydrogen absorption. Also 2B
By flowing warm wastewater of 80 ℃ to 1A and cooling water of 30 ℃ to 1A, a pressure drop of 2B> 1A is created in each hydrogen equilibrium decomposition pressure, and hydrogen flows from 2B to 1A. And the alloy of 2A and 2B, 1B
2A by continuously replacing the alloys of 1 and 1A
To continuously generate steam.

"Example-2" Next, the heat pump method in the case of generating cold heat using the same fluidized bed reactor and two sets of moving bed reactors 4 groups is demonstrated.

As described above, the hydrogen storage alloy in each reactor is fluidized by circulating hydrogen, and the alloy is moved by the hydrogen carrier gas and its own weight. However, a hot waste water heat source is placed in one of the low-pressure side reactors to obtain cold heat from one of the high-pressure side reactors. That is, the waste heat source is supplied to the low pressure side reactor 2B containing the second type hydrogen storage alloy (rich hydrogen storage alloy), and hydrogen is released by the moving bed reaction. Then, cooling water at 30 ° C. is passed through the high pressure side reactor 1A and the low pressure side reactor 2A to cool them. At this time, in the high pressure side reactor 1B containing the first type hydrogen storage alloy, hydrogen is released by the moving bed reaction, that is, the endothermic reaction is performed, and the MH heat exchanger is used.
Cold water at 5 ° C is obtained by passing water at 11 ° C through 11.

The above operation will be described with reference to the cycle diagram of FIG. The reference numerals are as described in FIG. 80 ° C warm wastewater in 2B, in 1B
When water of 10 ℃ is flowed and cooling water of 30 ℃ is flowed to 1A and 2A, a pressure drop of 2B> 1A, 1B> 2A is created in each hydrogen equilibrium decomposition pressure, and hydrogen flows from 2B to 1A and 1B to 2A. , 1B, cold water at 5 ° C. can be obtained by endothermic reaction due to hydrogen release. Then, the cold water is continuously obtained from 1B by continuously replacing the alloys of 1B and 1A and the alloys of 2A and 2B.

In the above example, the fluidized bed reactor 1A, 2A in the occlusion reaction,
Although the moving bed reactors 1B and 2B are used for the release reaction in the above description, it is of course possible to use 1B and 2B for storage and 1A and 2A for release.

The fluidized bed and moving bed reaction bonding method of the present invention can cope with the difference in the gas amount between the residual gas hydrogen carrier gas and the rich hydrogen carrier gas, as compared with the case of the fluidized bed or moving bed.
The operation control is also easy and flexible.

"Effect of the Invention" As described above, the method of the present invention is carried out in a reactor in which hydrogen storage (exothermic reaction) and release (endothermic reaction) are defined, and there is no switching operation and continuous operation There is no mixed liquid heat loss and sensible heat loss of the container metal as in the switching type multi-tube cylindrical heat exchanger type reactor, and therefore the supply energy and cooling energy for the same output energy are reduced. As a result, COP (heat recovery coefficient of performance) increases and running costs also decrease.

Also, the amount of hydrogen storage alloy used is 1/5 to 1/7 that of the fixed bed system, which is small because of continuous circulation of the fluidized bed and the moving bed.

In addition, since fluidized bed type and moving bed type reactors are used together, cycle operability is good, and since it does not require expensive filters and heat transfer improving materials, which are problems with fixed bed type, it is a continuous operation valve. No complicated control device is required.

As a result, the cost of the device as a whole is significantly reduced.

[Brief description of drawings]

FIG. 1 is an explanatory view of an embodiment of the present invention. 2 and 3 are cycle diagrams for explaining the operation. 1A, 1B: High pressure side reactor 2A, 2B: Low pressure side reactor 3: Fluidized bed, 4,5: Booster 6: Alloy separator, 7: Alloy catcher 8, 9: Gas heat exchanger 10, 11, 12, 13,: MH heat exchanger 14,15: Feeder

Claims (1)

[Claims] 1. One unit (1A) is a fluidized bed type and the other one unit (1B)
Is a moving bed type, two high pressure side reactors (1A, 1B) and one (2A) filled with a first type hydrogen storage alloy are fluidized bed type, and the other one is a moving bed type It is a type and uses a reaction vessel consisting of two sets of two low pressure side reactors (2A, 2B) filled with a second type hydrogen storage alloy, and circulates hydrogen between 1A and 2B and between 1B and 2A. This allows 1A and 2A to store hydrogen by fluidized bed reaction and 1B and 2B to carry out hydrogen desorption reaction by moving bed reaction.In addition, hydrogen is used as carrier gas for hydrogen storage alloy between reactors 1A and 1B and reaction. While moving and circulating between the reactors 2A and 2B respectively, the high pressure side reactor 1B and the low pressure side reactor 1B
Supply waste heat source to 2B, cool high pressure side reactor 1A, continuously obtain high temperature heat output from low pressure side reactor 2A, or supply waste heat source to low pressure side reactor 2B, high pressure side A heat pump method using hydrogen storage alloy, characterized in that the reactor 1A and the low pressure side reactor 2A are cooled, and the cold heat output is continuously obtained from the high pressure side reactor 1B.