JP2002340370A - Exhaust heat cascade using system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust heat cascade using system in which the heat of exhaust gas whose temperature is lowered by recovering heat in a heat recovery part can be further used and a thermal efficiency can be improved by effectively using the heat. SOLUTION: The exhaust heat cascade using system comprises a gas combustion device 1, the heat recovery part 2 for recovering the heat of the exhaust gas generated in the gas combustion device 1 and a desiccant dehumidifier 3 employing the exhaust gas whose heat is recovered by the heat recovery part 2 as regenerative gas of a dehumidifying agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of a system for utilizing a waste heat cascade utilizing the heat of exhaust gas from gas combustion equipment such as gas turbines and boilers.

[0002]

2. Description of the Related Art In gas combustion equipment such as gas turbines and boilers, high-temperature exhaust gas is generated in order to burn gas as fuel. However, conventionally, the heat of this exhaust gas has not been sufficiently used effectively. Conventionally, as a device that uses the heat of high-temperature exhaust gas emitted from gas combustion equipment, a heat recovery unit is arranged in the path of exhaust gas generated by gas combustion equipment, and the heat of the exhaust gas is converted into hot water or steam flowing to the heat recovery unit. Some are to be collected.

[0003]

However, even if the heat of the exhaust gas is recovered by the heat recovery unit, the temperature of the exhaust gas released to the atmosphere is often 100 ° C. or higher, and the heat is sufficiently recovered to recover the heat. It could not be said that it was used effectively.

[0004] The present invention has been made in view of the above points, and it is possible to further utilize the heat of exhaust gas whose temperature has been reduced by heat recovery in a heat recovery section, and to improve the heat efficiency by effectively utilizing the heat. It is an object to provide a heat cascade utilization system.

[0005]

In order to solve the above-mentioned problems, a system for utilizing a waste heat cascade according to the present invention comprises a gas combustion device 1 and a heat recovery unit 2 for recovering heat of exhaust gas generated in the gas combustion device 1. And a desiccant dehumidifier 3 that uses the exhaust gas after heat recovery by the heat recovery unit 2 as a dehumidifier regeneration gas.

[0006] With the above configuration, when exhaust gas generated by burning gas in the gas combustion equipment 1 is exhausted, heat is recovered from the high-temperature exhaust gas by the heat recovery unit 2. The exhaust gas whose heat has been recovered and the temperature of which has been lowered is supplied as a regeneration gas for the dehumidifier of the desiccant dehumidifier 3 to regenerate the dehumidifier, and the exhaust gas whose temperature has decreased due to the regeneration of the dehumidifier is exhausted to the atmosphere. . Therefore, the heat of the exhaust gas after heat recovery in the heat recovery unit 2 can be effectively used as heat for regeneration of the dehumidifier of the desiccant dehumidifier 3, that is, the heat of the low-temperature exhaust gas in which heat recovery is difficult in the heat recovery unit 2. Can also be used effectively accordingly, and the heat efficiency can be improved by effectively using the heat.

[0007] It is also preferable that the gas combustion equipment is a gas turbine. Gas turbines generally have a high air ratio, and therefore the absolute humidity in the exhaust gas based on the moisture generated by combustion is much lower than in other gas-fired appliances. As a result, the humidity of the exhaust gas sent to the desiccant dehumidifier 3 for regenerating the dehumidifier decreases, the regeneration capability of the dehumidifier increases, and the dehumidification capability of the desiccant dehumidifier 3 improves.

The desiccant dehumidifier 3 is characterized in that the temperature of the exhaust gas as a regenerating gas for the dehumidifier is 95 ° C. to 160 ° C., and the absolute humidity is adjusted to 40 g / kg dry exhaust gas or less. It is also preferred. in this case,
Even when the exhaust gas is used as the regeneration gas, the regeneration of the dehumidifier is effectively performed, and the desiccant dehumidifier 3 can sufficiently exhibit the dehumidification ability. Further, the long-term heat resistance of the dehumidifier can be maintained without exposing the dehumidifier to an excessively high temperature.

When the temperature of the exhaust gas used as the regeneration gas of the desiccant dehumidifier 3 is 95.degree. C. to 110.degree. C., the ratio of the regeneration air volume to the dehumidification air volume is 1: 1 to 1: 1.
1: 2, and the temperature of the exhaust gas is 110 ° C. to 160 ° C.
In this case, the ratio is preferably 1: 2 to 1: 4. In this case, the air volume for regeneration and the air volume for treatment can be optimized according to the temperature of the exhaust gas, and the desiccant dehumidifier 3 can efficiently dehumidify.

Also, a variable mechanism capable of varying the amount of heat recovered by the heat recovery unit 2 according to the demand for heat to be recovered by the heat recovery unit 2 or the demand for heat for regeneration of the desiccant dehumidifier 3 is provided. It is also preferable to have a feature. In this case, the heat of the exhaust gas can be separated and collected according to the heat demand, and can be used according to the situation.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an embodiment of the present invention will be described with reference to FIG. The gas combustion device 1 is operated by burning gas as fuel, and in the case of this example, is the gas turbine 1a. The gas turbine 1a rotationally drives the turbine with the pressure of the combustion gas when the gas is forcibly burned. In the case of this example, a generator is driven by a turbine to generate power. In the case of this example, the gas combustion device 1 is the gas turbine 1a, but may be a boiler that generates hot water or steam, a device that heats the absorption liquid of the absorption refrigerator, or another device. There may be. The exhaust gas generated by the gas turbine 1a serving as the gas combustion device 1 is released to the atmosphere. In the present invention, the heat of the exhaust gas is recovered by the heat recovery unit 2 and the desiccant dehumidifier 3 and then released to the atmosphere. You.

In the case of the present embodiment, the gas turbine 1a is used as the gas combustion equipment 1, but the use of the gas turbine 1a is preferable for the following reasons. Gas turbines generally have a high air ratio, so the absolute humidity in the exhaust gas based on the moisture generated by combustion is much smaller than in other gas-fired appliances. For this reason, the humidity of the exhaust gas used for regenerating the dehumidifier of the desiccant dehumidifier 3 can be reduced. By the way, the absolute humidity of the exhaust gas based on the moisture generated by the combustion of a water-supply type chiller / heater, boiler, etc. as other gas combustion equipment is 1
00 g / kg (the amount of moisture contained in 1 kg of dry exhaust gas), but the absolute humidity of the gas turbine is 50 g / kg.
kg or less, and in particular, a micro gas turbine used for power generation of 100 kW or less generally has an absolute humidity of 25 g / kg.
It is as follows.

Gas turbine 1a as gas combustion equipment 1
A heat recovery unit 2 for recovering the heat of the exhaust gas is disposed upstream of the exhaust path 5 for exhausting the exhaust gas generated in the above. In the example of FIG. 1, the heat recovery unit 2 is a heat exchanger 2a, and the heat exchanger 2a is disposed between the circulation path 6 for circulating hot water and the exhaust path 5, and the heat recovery unit 2 circulates with the exhaust gas passing through the exhaust path 5. The hot water circulating in the circulation path 6 is heated by exchanging heat with the hot water circulating in the path 6. In the case of this example, the hot water circulating in the circulation path 6 is heated, but the steam may be circulated in the circulation path 6 to heat the water vapor.

Further, in the case of this embodiment, the absorption liquid of the absorption refrigerator 4 is preheated by the hot water circulating in the circulation path 6. In this embodiment, the absorption refrigerator 4 is a gas-fired absorption chiller / heater 4a, and the absorption liquid is heated by burning gas. In the case of this example, the gas-fired absorption-type chiller / heater 4a is used, but a steam-fired absorption-type chiller-heater or a hot-water-absorption absorption-type chiller / heater may be used.

Since the gas-fired absorption-type chiller / heater 4a is well known, a detailed description thereof will be omitted, but as shown in FIG. 2, an evaporator 7 for evaporating a refrigerant (water) liquid, and the evaporator 7
Absorber 8 that absorbs the refrigerant vapor generated in the above into absorbent (LiBr), and regenerator 9 that regenerates the absorbent by heating the diluted absorbent generated by the absorber 8 to generate refrigerant vapor. And a condenser 10 for condensing the refrigerant vapor generated in the regenerator 9 so as to be able to switch between a cold water generating operation for generating cold air for air conditioning and a hot water generating operation for generating hot water for air conditioning. It is configured in. Although a detailed description is omitted, the cold water generation operation is performed so that cold water is obtained based on the removal of latent heat of vaporization by the evaporation of the refrigerant in the evaporator 7, and the hot water generation operation uses the refrigerant vapor generated in the regenerator 7. The refrigerant is supplied to the evaporator 7 to obtain hot water using the refrigerant vapor as a heat source, or to obtain hot water using the absorption heat generated in the absorber 8 and the condensation heat generated in the condenser 10 as heat sources.

In the case of the gas-fired absorption chiller / heater 4a of the above example, the cycle is a double effect cycle, and the regenerator 9 is a high temperature regenerator 9
a and a low-temperature regenerator 9b. High temperature regenerator 9
a is designed to heat by gas combustion by supplying a fuel gas such as city gas, and the high-temperature refrigerant vapor generated in the high-temperature regenerator 9a passes through the low-temperature regenerator 9b, so that the low-temperature regenerator 9b is heated. It is designed to be heated,
Both the refrigerant vapor passed from the high-temperature regenerator 9a and the low-temperature regenerator 9b and the refrigerant vapor generated in the low-temperature regenerator 9b are sent to the condenser 10 to be condensed. The absorbent separated by the high-temperature regenerator 9a is sent to the low-temperature regenerator 9b, and is sent from the low-temperature regenerator 9b to the absorber 8. The absorption liquid sent from the low-temperature regenerator 9b to the absorber 8 and the diluted absorption liquid sent from the absorber 8 to the high-temperature regenerator 9a correspond to the low-temperature heat exchanger 1
The heat is exchanged at 1 to heat the diluted absorption liquid. The absorption liquid sent from the high-temperature regenerator 9a to the low-temperature regenerator 9b and the diluted absorption liquid sent from the absorber 8 to the high-temperature regenerator 9a exchange heat in the high-temperature heat exchanger 12 so that the diluted absorption liquid is heated. It has become. In addition, from the absorber 8 to the high-temperature regenerator 9
A hot water heat exchanger 13 is disposed between the low-temperature heat exchanger 11 and the high-temperature heat exchanger 12 in the path for sending the diluted absorption liquid to a, and recovers the heat of the exhaust gas and flows through the circulation path 6. The diluted absorption liquid is heated by exchanging heat with warm water. This makes it possible to preheat the rare absorbing liquid sent to the high-temperature regenerator 9a and reduce the amount of fuel required for heating in the high-temperature regenerator 9b.

In the above example, the heat of the exhaust gas is recovered and the hot water flowing through the circulation path 6 is heated to preheat the absorbing solution sent to the regenerator 9, but the absorbing solution of the regenerator 9 is directly heated by the heat of the exhaust gas. You may make it heat. That is, the exhaust gas exhaust path 5 is directly introduced into the regenerator 9 and this portion is
The regenerator 9 may be heated only by the heat recovered from the exhaust gas.

When the exhaust gas is directly fed into the regenerator 9, a double effect cycle and a single effect cycle are provided side by side with one absorption chiller / heater, and the heat of the exhaust gas is converted into a double effect cycle → single effect cycle. The exhaust heat may be recovered by cascade charging in the cycle order. In this case, the thermal efficiency can be increased.

In the above example, the heat recovered by the heat recovery unit 2 is used for the absorption type chiller / heater. However, this heat may be used for the adsorption type refrigerator. The adsorption refrigerator is a refrigerator known in, for example, JP-A-2-230068, and a description thereof is omitted. In the case of this adsorption type refrigerator, regeneration is performed by heating the adsorbent heat exchanger with hot water, and in the case of the present invention, heating is performed with hot water flowing through the circulation path 6.

The exhaust gas from which heat has been recovered by the heat recovery unit 2 is then used as a regeneration gas for the dehumidifier in the desiccant dehumidifier 3, and the desiccant dehumidifier 3 is configured as follows. The desiccant dehumidifier 3 is mainly configured to dehumidify by a dehumidification rotor 14. The dehumidifying rotor 14 is provided with a dehumidifying agent such as silica gel on a disk that is slowly driven to rotate at a constant speed, and dehumidifies the dehumidifying agent on the primary side 14a of the dehumidifying rotor 14 to dehumidify the air passing through the primary side 14a. At the same time, a high-temperature regeneration gas is applied to the secondary side 14b of the dehumidification rotor 14 to release moisture from the dehumidifier and regenerate the dehumidifier. In the case of the present invention, the exhaust gas after heat recovery in the heat recovery unit 2 is used as a regeneration gas.

In the desiccant dehumidifier 3, a sensible heat rotor 15 for sensible heat exchange is provided in addition to the dehumidifier rotor 14. The sensible heat rotor 15 is also similar to the dehumidification rotor 14, and the heat storage disk is slowly rotated at a constant speed, so that the primary side 1
The structure is such that heat moves from 5a to the secondary side 15b. The outdoor air is supplied to the desiccant dehumidifier 3 by the dehumidification rotor 1.
An air supply path 16 is provided so that air is supplied into the room through the primary side 14a of the humidifying rotor 14 and the primary side 15a of the sensible heat rotor 15, and the exhaust gas passes through the secondary side 14b of the dehumidifying rotor 14 as a regeneration gas. A regeneration gas path 17 is provided so as to be exhausted outside the room, and a ventilation path 18 is provided so that outdoor air passes through the secondary side 14 b of the sensible heat rotor 14. The regeneration gas path 17 communicates with the exhaust gas exhaust path 5.

When the outdoor air is supplied into the room from the air supply path 16, the air is supplied to the ventilation path 18, and the exhaust gas is supplied to the regeneration gas path 17, the air supplied from the outdoor is supplied to the dehumidifying rotor 14.
The dehumidifier is dehumidified by passing through the primary side 14 a, while the exhaust gas is regenerated in the regeneration gas path 17 so as to be released from the dehumidifier by hitting the secondary side 14 b of the dehumidifier rotor 14. The dehumidified air passing through the primary side 14a passes through the primary side 15a of the sensible heat rotor 15 and is cooled by sensible heat exchange with the air passing through the ventilation path 18, so that air having a relatively low temperature and low humidity is produced. Air is supplied indoors.

As described above, the desiccant dehumidifier 3 performs dehumidification. The amount of processing air to be dehumidified through the air supply path 16 and the regeneration gas passage 1 according to the temperature of the exhaust gas as the regeneration gas.
It is desirable to set the following relationship between the flow rate of the exhaust gas passing through and the flow rate for regeneration. When the temperature of the exhaust gas used as the regeneration gas is 95 ° C to 110 ° C, the ratio between the regeneration air volume and the processing air volume is 1: 1 to 1: 2, and when the exhaust gas temperature is 110 ° C to 160 ° C, the regeneration is performed. 1: 2 for the ratio of the air volume for processing to the air volume for processing
From 1: 4. Air supply path 16 of desiccant dehumidifier 3
In general, the absolute humidity of the air supplied into the room can be reduced by increasing the ratio of the air volume for regeneration to the air volume for processing and the temperature of the exhaust gas supplied to the desiccant dehumidifier 3.

As described above, the desiccant dehumidifier 3 regenerates the dehumidifier with the exhaust gas. If the exhaust gas has a high absolute humidity or temperature, the humidity or the temperature is reduced by mixing outside air or indoor return air. At this time, the absolute humidity of the exhaust gas is 3
More preferably, it is 0 g / kg or less. The temperature of the exhaust gas regenerated due to the long-term heat resistance of the dehumidifier is 160 ° C.
The following is desirable.

It is also desirable to dispose a total heat exchanger in a portion where air is supplied from outside to the air supply path 16. This total heat exchanger exchanges total heat of sensible heat and latent heat between the air passing through the primary side and the air passing through the secondary side, and converts the air supplied from the outdoor to the primary side of the total heat exchanger. And the exhaust air from the room is passed through the secondary side of the total heat exchanger, so that the total heat exchange can be performed to lower the humidity and temperature of the supply air.

Next, the overall operation of the system configured as described above will be described as follows. Gas combustion equipment 1
When the gas turbine 1a is operated, power is generated. At this time, for example, exhaust gas of about 300 ° C. is exhausted through the exhaust path 5. Then, heat is recovered from the exhaust gas passing through the exhaust path 5 in the heat recovery unit 2, and the recovered heat is used as heat of an absorption chiller / heater or an adsorption chiller to cool indoor air conditioning and refrigeration equipment. Will be Exhaust gas whose temperature has been reduced to, for example, about 100 ° C. by the heat recovery unit 2 is supplied to the regeneration gas path 17, and the secondary side 14 b of the dehumidification rotor 14 is heated to regenerate the dehumidifying agent. The exhaust gas that has become exhausted outside the room. On the other hand, the air supplied from outside through the air supply path 16 is dehumidified by passing through the primary side 14a of the dehumidification rotor 14, and low-humidity air is supplied to the room. As a result, heat can be first recovered from the exhaust gas in the heat recovery unit 2 and used for air conditioning and the like, and the heat of the temperature-reduced exhaust gas after heat recovery in the heat recovery unit 2 is regenerated by the desiccant dehumidifier 3 as a dehumidifier. Heat can be effectively used, and the heat efficiency can be improved by effectively using the heat.

Next, another example of the embodiment shown in FIG. 3 will be described. This example is also basically the same as the above example, and only different points will be mainly described. The heat recovery section 2 is disposed in the exhaust path 5, but a bypass path 19 is provided in the exhaust path 5 so as to be parallel to the portion provided with the heat recovery section 5.
A damper 20 is provided in the bypass path 19. In this case, by opening and closing the damper 20, the amount of exhaust gas passing through the heat recovery unit 5 can be adjusted, and it is possible to meet the demand for heat recovered by the heat recovery unit 2. Downstream of the heat recovery section 5 and the bypass path 19, the exhaust path 5 is provided with a branch path 21 for directly exhausting air to the outside of the room, and a damper 22 is arranged in the branch path 21. In this case, by opening and closing the damper 22, the amount of exhaust gas sent to the regeneration gas path 17 can be adjusted, and it is possible to meet the demand for heat for dehumidifier regeneration.

[0028]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to specific examples. (Example 1) The system shown in FIG. 1 was operated as follows (the numerical values added to FIG. 1 are those of Example 1).

Two gas turbines, each generating 28 kW, were driven as gas-fired devices to generate 56 kW. At this time, the input amount of natural gas for driving the gas turbine was 224 kW, and the power generation efficiency was 25%. The exhaust gas discharged from the gas turbine has a temperature of 290 at the turbine outlet.
° C, absolute humidity 39 g / kg DG (1 kg DG = dry exhaust gas), and the exhaust gas amount was 1530 Nm ³ / h.

In the exhaust gas heat exchanger as the heat recovery unit, the exhaust gas flowing in the exhaust path and the hot water flowing in the circulation path exchange heat to raise the temperature of the hot water in the circulation path from 83 ° to 88 ° C. At this time, the recovered heat amount is 102 kW and the outlet exhaust gas temperature is 10
It was 0 ° C.

The natural gas-fired absorption cooling water heater using the heat recovered from the heat recovery has an output of 350 kW, the natural gas input amount used to heat the absorbing liquid is 273 kW, and the exhaust heat input by the hot water is used. The amount is 102 kW (hot water temperature 88
° C → 83 ° C). At this time, the reduction ratio of the input amount of the natural gas due to the input of the exhaust heat was 22% (350 kW of the natural gas input when there was no exhaust heat), and the contribution of the refrigeration output to the exhaust heat was 77 kW.

As the desiccant dehumidifier, a dehumidifier having a built-in sensible heat rotor for sensible heat exchange with a dehumidifier rotor made of silica gel and having a total heat exchanger as a pretreatment was used. The outdoor air condition at this time was a temperature of 29.3 ° C. and an absolute humidity of 11.8 g / kg DA (1 kg DA = 1 kg of dry air). The air flow for supplying outside air from the air supply path of the desiccant dehumidifier is 2000 m ³ / h, and the inlet temperature of the exhaust gas in the regeneration gas path of the desiccant dehumidifier is 100 ° C.
, The outlet temperature was 77 ° C., and the exhaust heat input was 13 kW.
The ratio of the amount of regeneration air flowing on the secondary side of the dehumidifying rotor to the amount of processing air flowing on the primary side of the dehumidifying rotor was 1/1. The secondary side, which is the regeneration side of the sensible heat rotor, was cooled by outside air and exhausted. The temperature of the supply air at the outlet on the processing side was 29.1 ° C., the absolute humidity was 6.4 g / kg DA, and the output of the desiccant dehumidifier was 9.5 kW (= enthalpy of outside air and supply air × air volume).

As described above, by using the heat of the exhaust gas for the exhaust heat input natural gas-fired absorption chiller / heater and desiccant dehumidifier, the overall efficiency is 64% ｛= (56 kW of power generation + 77 kW of absorption chiller / heater + desiccant dehumidifier 9). .5 kW) / natural gas input 224 kW｝. (Comparative Example 1) Exhaust gas was exhausted to the outside air after exchanging heat with an exhaust gas heat exchanger as a heat recovery unit without supplying exhaust gas to the desiccant dehumidifier in Example 1 described above.

As described above, the heat of the exhaust gas is transferred to the exhaust heat input type natural gas.
Overall efficiency is 59% if only a steam absorption cooling water heater is used
= {(56 kW of power generation + 77 kW of absorption chiller / heater) / Natural
To 224 kW}. Also targeted
2000m ventilation load of room^Three/ H processing
Heat source was needed. (Comparative Example 2) A hot water boiler was used as a gas combustion device,
City gas (caloric value 12.8 kW / Nm ^ThreeHot water burning in)
180 ° C, air volume 230 from boiler 143kW
m^Three/ H ｛air volume 80 ° C conversion, moisture ratio 14.5 vol%,
Absolute humidity 109g / kgDG (1kgDG = dry exhaust gas
S) Recover 70 ° C hot water from the exhaust gas of ① by heat exchanger
And then desiccant dehumidification of exhaust gas that has dropped to 140 ° C
I put it in the machine. The desiccant dehumidifier of this comparative example has a sensible heat
A rotor having only a dehumidifying rotor without a pad was used. This desiccan
Air treated with a dehumidifier (outside air, temperature 30 ° C, absolute
The amount of humidity 17g / kgDA) is 690m^Three/ H
The area ratio between the regeneration zone and the processing zone of the dehumidifying rotor is 1:
It was set to 3. Also, the surface velocity of processing air and regeneration air (converted to 80 ° C)
Divided by the cross-sectional area of each zone)
Dehumidification rotor of the size (diameter) that both become 2 m / s
(The thickness was 200 mm). Dehumidifier for dehumidifying rotor
Is silica gel. At this time, due to the long-term heat resistance of the dehumidifier,
A regeneration temperature of less than 160 ° C. was selected.

As a result, the absolute humidity of the air exiting from the outlet of the treated air was 13 g / kg DA (this is 62% when the relative humidity when used after cooling to 26 ° C.). This process air is generally set by air conditioning in summer.
10.5 g / absolute humidity corresponding to 6 ° C. and 50% relative humidity
It became much larger than kgDA. (Example 2) 1388 of the exhaust gas cooled to 140 ° C in Comparative Example 2 was exposed to outside air (30 ° C, absolute humidity 17 g / kg DA).
m ³ / h, and the mixture was reheated to 140 ° C. to recover a regeneration gas (16 g / kg DG (dry exhaust gas) having an absolute humidity of 30 g / kg).
18 m3 / h) and put into a dehumidifying rotor. The amount of processing air (outside air, 30 ° C., absolute humidity 17 g / kg DA) was 4850 m ³ / h. The area ratio between the regeneration zone and the processing zone of the dehumidifying rotor was 1: 3. Use a dehumidifying rotor (200 mm thick) with a size (diameter) of 2 m / s for both the surface velocity of the treated air and the regeneration air (the value obtained by dividing the air volume converted to 30 ° C. by the cross-sectional area of each zone). did. The dehumidifying agent of the dehumidifying rotor was silica gel.

As a result, the absolute humidity of the air discharged from the outlet of the treated air was 9.8 g / kg DA (this is 47% when the relative humidity when used after cooling to 26 ° C.). In the present embodiment, since the absolute humidity of the exhaust gas fed to the desiccant dehumidifier can be reduced, dry air having a lower absolute humidity than in Comparative Example 2 could be obtained. This dry air could be made lower than 10.5 g / kg of absolute humidity corresponding to 26 ° C. and 50% relative humidity, which are generally set by air conditioning in summer. (Comparative Example 3) In Example 2, when the temperature of the exhaust gas for regeneration was 70 ° C, the area ratio between the regeneration zone and the treatment zone of the dehumidifying rotor was set to 1: 1 to increase the ratio of the regeneration zone.

As a result, despite the enlarged regeneration zone, the absolute humidity of the air exiting from the processing air outlet of the desiccant dehumidifier was 13.1 g / kg DA. This dry air is generally set at 26 ° C. and a relative humidity of 5 in air conditioning in summer.
The absolute humidity was significantly higher than 10.5 / kg DA corresponding to 0%. (Embodiment 3) In Embodiment 1, the exhaust heat input type natural gas-fired absorption cooling water heater of Embodiment 1 is used in which the exhaust gas is directly injected into the regenerator without using a fuel gas to heat the absorbing liquid. Was replaced with an absorption type chiller / heater. At this time, the charging temperature of the exhaust gas to the desiccant dehumidifier was 100 ° C. as in the first embodiment.
And showed the same performance as a desiccant dehumidifier.
This system was driven only by waste heat and was able to form a double-effect cycle and a single-effect cycle at the same time. Further, the conversion efficiency of the exhaust heat into the cold heat in the absorption chiller / heater is 1.0, and the conversion efficiency of the first embodiment is 0.75 (= 77 kW / 10
2 kW). (Example 4) Under the same conditions as in Example 1, the ratio of the air flow for regeneration of the dehumidifying rotor to the processing air flow (hereinafter abbreviated as air flow ratio) and the temperature of the exhaust gas to be supplied to the desiccant dehumidifier are changed to change the absolute value of the processing side outlet (air supply). The change in humidity was examined. As a result, it was as follows. (1) When the exhaust gas temperature is 95 ° C. or more, the absolute humidity hardly changes even if the air volume ratio is made larger than 1/1, for example, 100 ° C.
Was almost the same as in Example 1. Therefore, it has been found that it is preferable to make the ratio equal to or less than 1/1 in consideration of economy. (2) When the exhaust gas temperature was 110 ° C. or less and the air volume ratio was reduced to １ ／, the absolute humidity increased. For example, when the exhaust gas temperature was 110 ° C. and the ratio was reduced to ３, the absolute humidity increased to about 8 g / kg DA. Assuming that the ratio was 1/2, the absolute humidity could be made almost the same as in Example 1. (3) It was found that even when the exhaust gas temperature was 110 ° C. or more, the reduction in absolute humidity was small even when the ratio was １ ／ or more. Therefore, it was found that it is preferable to make the ratio equal to or less than 1/2 in consideration of economy. (4) When the exhaust gas temperature is 160 ° C. or less and the air volume ratio is less than 1/4, the absolute humidity increases, for example, the exhaust gas temperature is 160 ° C.
When the ratio was reduced to 1/5, the absolute humidity increased to about 8 g / kg DA. Assuming that the ratio was 1/4 at an exhaust gas temperature of 16 ° C., the absolute humidity could be made almost the same as in Example 1.

[0038]

According to the first aspect of the present invention, there is provided a gas combustion apparatus, a heat recovery section for recovering heat of exhaust gas generated in the gas combustion apparatus, and an exhaust gas after recovering heat in the heat recovery section. Since it has a desiccant dehumidifier that uses as a regeneration gas for the dehumidifier, when exhaust gas generated by burning gas with gas combustion equipment, heat is recovered from the high-temperature exhaust gas in the heat recovery unit, Exhaust gas whose temperature has been reduced by heat recovery in the heat recovery section is supplied as a regeneration gas for the dehumidifier of the desiccant dehumidifier, and the dehumidifier is regenerated. Therefore, the heat of the exhaust gas after heat recovery in the heat recovery unit can be effectively used as heat for regenerating the dehumidifier of the desiccant dehumidifier. Exhaust gas heat It can be effectively utilized accordingly, in which by effectively utilizing the heat can improve the thermal efficiency.

The invention of claim 2 of the present invention is directed to claim 1
In, since the gas combustion device is a gas turbine, the humidity of the exhaust gas sent for the regeneration of the dehumidifier to the desiccant dehumidifier is reduced, the regeneration capacity of the dehumidifier is increased,
This improves the dehumidifying capacity of the desiccant dehumidifier.

Further, the invention of claim 3 of the present invention is directed to claim 1
Alternatively, the temperature of the exhaust gas as a regenerating gas for the dehumidifier of the desiccant dehumidifier is 95 ° C to 160 ° C.
° C, and the absolute humidity is adjusted to 40 g / kg or less of dry exhaust gas. Therefore, even when exhaust gas is used as a regeneration gas, regeneration of the dehumidifier is effectively performed and the desiccant dehumidifier has a sufficient dehumidifying capacity. In addition, the dehumidifier can maintain its long-term heat resistance without being exposed to an excessively high temperature.

Further, the invention of claim 4 of the present invention is directed to claim 1
The exhaust gas used as a regeneration gas of the desiccant dehumidifier according to any one of claims 3 to 5, wherein the temperature of the exhaust gas is 95 ° C to 1 ° C.
In the case of 10 ° C., the ratio of the air volume for regeneration to the air volume for the dehumidification process is 1: 1 to 1: 2, and the temperature of the exhaust gas is 110
In the case where the temperature is from 0 ° C to 160 ° C, the ratio is from 1: 2 to 1: 4, so that the air volume for regeneration and the air volume for treatment can be optimized according to the temperature of the exhaust gas, and the desiccant dehumidifier can efficiently dehumidify. .

Further, the invention of claim 5 of the present invention is directed to claim 1
The variable mechanism according to any one of claims 4 to 4, further comprising a variable mechanism capable of changing a recovery amount in the heat recovery unit according to a demand for heat to be recovered in the heat recovery unit or a demand for regeneration heat of the desiccant dehumidifier. Therefore, the heat of the exhaust gas can be separated and collected according to the heat demand, and can be used according to the situation.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an example of the system of the present invention.

FIG. 2 is an explanatory view illustrating the structure of the gas-fired absorption-type chiller / heater according to the first embodiment.

FIG. 3 is a system diagram showing another example of the above system.

[Explanation of Signs] 1 Gas combustion equipment 2 Heat recovery unit 3 Desiccant dehumidifier

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Toshikuni Ohashi 4-1-2, Hirano-cho, Chuo-ku, Osaka-shi F-term in Osaka Gas Co., Ltd. (reference) 3K070 DA08 DA09 DA24 DA35 DA81 3L053 BC03 BC09

Claims (5)

[Claims] 1. A gas combustion device, a heat recovery unit for recovering heat of exhaust gas generated in the gas combustion device, and the exhaust gas after recovering heat in the heat recovery unit is used as a regeneration gas for a dehumidifier. A waste heat cascade utilization system comprising a desiccant dehumidifier. 2. The system according to claim 1, wherein the gas combustion device is a gas turbine. 3. The desiccant dehumidifier according to claim 1, wherein the temperature of the exhaust gas as a regenerating gas for the dehumidifier is 95 ° C. to 160 ° C., and the absolute humidity is adjusted to 40 g / kg or less. The waste heat cascade utilization system according to claim 1 or 2. 4. When the temperature of the exhaust gas used as the regeneration gas of the desiccant dehumidifier is 95 ° C. to 110 ° C., the ratio of the regeneration air volume to the dehumidification treatment air volume is 1: 1 to 1: 2.
The exhaust heat cascade according to any one of claims 1 to 3, wherein when the temperature of the exhaust gas is 110C to 160C, the ratio is 1: 2 to 1: 4. Usage system. 5. A variable mechanism capable of varying a recovery amount in the heat recovery unit according to a demand for heat recovered by the heat recovery unit or a demand for regeneration heat of the desiccant dehumidifier. The exhaust heat cascade utilization system according to any one of claims 1 to 4.