JPS5977083A - Waste-heat recovering apparatus - Google Patents

Abstract

PURPOSE:To take-out motive-power from gas energy by utilizing the gas occluding metal which occludes gas and discharges the gas having a pressure through heating and by the repetition of discharge and occlusion of gas by heating and cooling the metal. CONSTITUTION:A heat exchanger 2 is installed onto a discharge apparatus 1 for discharging hydrogen gas from the hydrogen occluding metal which occludes hydrogen gas. A power generator 4 generates electric power by ustilizing the motive power supplied from an expansion machine 3 for decompressing the hydrogen gas having a pressure which is discharged from the discharge apparatus 1. Said hydrogen gas having a pressure is sent into the gas expansion machine 3 and decompressed. The energy due to expansion of hydrogen gas is taken-out as the rotary power for a shaft by the expansion machine and used for driving the power generator 4 to generate electric power. Since the temperature of the hydrogen gas which is adiabatically expanded lowers below the temperature before decompression, the hydrogen occuluding metal can be used as the cooling heat-source for a refrigerator.

Description

[Detailed description of the invention] The present invention relates to a low temperature level factory waste heat recovery device.

Conventionally, there has been no method or device for recovering power using low-level factory exhaust heat of 100° C. or less.

Since the oil shock, energy conservation has been progressing in factories, and the main focus of this is the effective use of waste heat. The high-temperature exhaust heat generates steam, which rotates a turbine and recovers power as electricity. In the above method, steam is generated from water or chlorofluorocarbons, so the waste heat is approximately 130℃.
A temperature higher than that is required, and currently there is almost no means of recovering waste heat below 130°C and it is thrown away.

Although it is not a recovery method for power, there is also a method of raising the temperature of J and I heat at the 40°C level to the 80°C level by using an energy-saving device at a low temperature level (7) and an absorption refrigerator as a heat pump. However, increasing the temperature to this extent would not produce any economic benefits.

In this manner, the present inventor has been searching for an energy-saving method that effectively recovers waste heat of about 100° C. as power.

The present invention was developed in view of the above, and uses a gas storage metal to generate cycle gas pressure during exhaust heat recovery, and converts waste heat at a level of 100°C, which was conventionally discarded, into electricity. The purpose is to collect

To this end, the present invention is characterized by using a storage metal that stores gas and discharges the gas under pressure when heated, and by heating and cooling the storage metal,
The purpose is to form a cycle in which the gas is discharged and stored repeatedly, and power is extracted from the energy of the gas discharged from the storage metal.In order to achieve the above heat recovery method, the storage metal is heated. a gas expander for extracting motive power by expanding the gas from the exhaust device; and a cooling means for extracting power from the gas expander. The heat recovery device consists of an occluding device that stores gas from the occluding metal in an occluding metal.

The present invention can be widely applied to low temperature level exhaust heat recovery devices.

Hereinafter, with reference to FIGS. 1 and 2, an embodiment will be described in which hydrogen is used as the gas and a hydrogen storage metal is used as the storage material.

The first embodiment will be explained with reference to FIG.
Reference numeral 1 denotes a discharge device for discharging hydrogen gas from a hydrogen storage metal that has stored hydrogen gas, and a heat exchanger (2) for discharging hydrogen gas is inserted into the discharge device (1). (3) is hydrogen at a pressure discharged by the discharge device (5 is a bypass flow path when hydrogen gas is not used as a cold source, (6)
(7) is a heat exchanger that removes the heat stored in the storage device (6); (8) is a device that discharges the storage metal that has stored hydrogen in the storage device (6); (
(9) is a pressure sealing device that seals the pressure difference between the discharge device (1) and the storage device (6), and OI.
is a heat exchanger for exchanging heat between the storage metal sent from the discharge device (1) to the storage device (6) and the storage metal sent from the storage device (6) to the discharge device (1), and is an exhaust heat recovery device. is composed of the above parts.

In the above device, the discharge device (1) is filled with a hydrogen storage metal that stores hydrogen gas. In order to discharge hydrogen gas from the hydrogen storage metal, approximately 10
Pass exhaust steam or heated exhaust water around 0°C. Hydrogen storage metal has a temperature of 8 to 10 KF/ when heated above 80'C.
Generates hydrogen gas with a pressure of 7 abs. The relationship between the heating temperature and the exhaust hydrogen gas pressure is determined by the components of the hydrogen storage metal. As examples of hydrogen storage metals, alloys made of iron, titanium, zirconium, niobium, etc., alloys made of titanium-zinc, etc., alloys made of Ninocur, zirconium, etc. are used.

The hydrogen gas under pressure is sent to a gas expander (3),
The pressure is approximately isentropically reduced to about 2 g/cJ'ab s. The energy when the hydrogen gas expands is extracted as rotational force of the shaft by the expander, and is generated by the generator (4).
drive and generate electricity. The temperature of the adiabatically expanded hydrogen gas is lower than the temperature before depressurization, so it can be used as a cold source for a refrigeration system. When cooling other process fluids, they are cooled by a heat exchanger (5). When not cooling, the hydrogen gas is not passed to the heat exchanger (5) by bypass (5).The expanded hydrogen gas is sent to the storage device (6).The storage device also has a discharge device (1). ), the storage metal that has discharged hydrogen gas is sent to the storage device (
6) has a heat exchanger (7) that removes stored heat, and is fed with cooling water or the like from a commonly used cooling tower. And the hydrogen storage metal is 20'C~3
It absorbs hydrogen gas by being cooled to 5°C. The storage metal that has absorbed hydrogen is sent to a discharging device (1) by a conveying device such as a screw feeder (57).

Further, the storage metal that has discharged hydrogen gas in the discharge device (1) passes through a pressure seal device (9) such as ball pulp for granules using the pressure difference between the discharge device and the storage device as a driving force, and passes through the storage device ( 6).

Furthermore, in order to improve the thermal efficiency of this system, there is a heat exchanger 00), in which heat exchange is performed between the storage metal sent from the discharge device to the storage device and the storage metal sent from the storage device to the discharge device.

Thereafter, the same cycle is repeated by similarly circulating hydrogen gas and storage metal.

As mentioned above, the one in Figure 1 generates hydrogen gas under pressure by using exhaust heat at the 100°C level as the exhaust heat source of the hydrogen storage metal, extracts work using an expander, and generates electricity. I can do it.

Therefore, electricity can be recovered by using waste heat at a level of 100°C, which was conventionally wasted, and energy saving can be achieved.

Although Example 1 circulated the hydrogen storage metal, an example of a batch process without circulation is shown in Example 2 with reference to FIG.

In FIG. 2, the same members as those in FIG. 1 are given the same reference numerals. The one in Figure 2 is a container (20) filled with a hydrogen storage metal that can store and discharge hydrogen gas, Cυ, (two examples are shown, but 2
heat exchanger (22), (c), heat source (22), which provides heat for occlusion and discharge, respectively (sometimes composed of two or more);
24) Dam valve to switch the heat from (25+ (26)
), a valve (2) for switching the cold and heat from the cooling source (27)
al, (2!ll, Valve side for switching the hydrogen gas to be discharged, 0D, Valve for switching the hydrogen gas to be occluded (321,, (331, Valve control device for automatically controlling the opening and closing of the valve) 341, a gas expander (3), a generator (4), a heat exchanger (
5) and a bypass (5)r.

In Example 1, the hydrogen storage device (6) shown in FIG. 1 had only a storage function, and the discharge device (1) had only a discharge function. 20)
, 01) is a batch process in which storage and discharge are alternately repeated.

That is, when the container (20) discharges hydrogen gas, a stop valve (
25) is open, and valve 06) is closed. In the trench, the valve (31) is closed to send the exhausted hydrogen gas to the expander (3).

The expander (3), the generator (4), the heat exchanger (5), and the bypass passage (5)' function in the same manner as described in the first embodiment. In order to store hydrogen gas after expansion, the container (2I) is made to perform a storage action. Therefore, in order to send the cold heat from the cooling source (27) to the heat exchanger (23), the valve (2 mark is open, valve C'9) is closed, and the valve t3 is closed to send hydrogen gas to the container Qυ. □□□ is open, valve (3
It's closed.

When the discharge of hydrogen gas from the container (A) and the occlusion in the container (2υ) are completed, at the same time, the opening and closing of all the above-mentioned valves are reversed by the signal from the valve control device 0a. Also, the container CD can be switched from occlusion to expulsion.

By repeating this, hydrogen gas having a substantially constant pressure can be supplied to the expander (3).

Note that, at present, the switching time is approximately 30 minutes.

The switching of containers (a) and (21) has been explained above, but
The effect of the discharged hydrogen gas is similar to that described in Example 1. Also, depending on the type of hydrogen storage metal to be filled, the storage time and discharge time may differ, but it is possible to add three or four containers similar to containers (20) and (21). By controlling three or more containers in the same manner as described above, it is possible to constantly supply pressurized hydrogen gas to the expander (3).

In Example 2, the same 10
By using waste heat at the 0° C. level as the exhaust heat source of the hydrogen storage metal, hydrogen gas under pressure can be generated, and work can be extracted by the expander to generate electric power.

The exhaust heat recovery method and device using a combination of hydrogen gas and hydrogen storage metal have been described above. FIG. 2 is a system diagram showing a second embodiment.

11. Hydrogen gas extraction device; 2. '5, 7.10... Heat exchanger, 3... Gas expander, 4... Generator, 5'... Bypass passage, 6... Hydrogen gas storage device, 8... Transfer device, 9...・Pressure sealing device, 20, 2]...Hydrogen storage metal filling container, 22.23...Heat exchanger, 24...Heat source,
25, 26.28, 29'.

30, 31, 32. 33... Valve, 27... Cooling source, 34
...Valve control device.

Figure 1

Claims (2)

[Claims] (1) Using a storage metal that stores gas and releases the gas under pressure when heated, a cycle is formed in which the gas is repeatedly discharged and stored by heating and cooling the storage metal, and A heat recovery method characterized by extracting power from the energy of gas discharged from storage metal. (2) A discharge device that has means for heating the storage metal and discharges gas under pressure from the storage metal, a gas expander that extracts power by expanding the gas from the discharge device, and a cooling means. and a storage device for storing gas from the gas expander in the storage metal.