JPH0618609B2 - Ventilation gas purification equipment for road tunnels, etc. - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is, for example, various road tunnels, mountain tunnels, subsea tunnels, underground roads, roads with shelters, etc. (in the present specification, these tunnels are collectively referred to as “tunnels”). (Hereinafter referred to as "road tunnel etc."), the present invention relates to a purification device for efficiently removing relatively low-concentration nitrogen oxides (NOx) contained in ventilation gas to purify the ventilation gas.

[Background of the Invention] In a road tunnel or the like, particularly for a long and heavy vehicle traffic, a considerable amount of air in the tunnel is sucked or exhausted in order to protect the health of drivers, passers, etc. and improve the visual distance. Needs ventilation. Even in a relatively short-distance tunnel, in the urban area or its suburbs, the air in the tunnel is still ventilated in order to prevent air pollution due to carbon monoxide (CO), NOx, etc. concentrated at the entrance / exit. . The ventilation gas thus produced has a NOx concentration of about 5 ppm.

However, if ventilation gas is diffused to the surroundings as it is, it not only causes environmental pollution in the area, but also expands highly polluted areas especially in urban areas where automobile exhaust gas pollution spreads flat or in the suburbs. It can happen. The above-mentioned circumstances are exactly the same when a road tunnel is constructed or a shelter is installed as a measure against pollution of the existing road.

The present invention relates to a device for purifying ventilation gas by efficiently removing low-concentration NOx contained in ventilation gas for such road tunnels.

[Prior Art and Problem of the Invention] Conventionally, exhaust gas purifying apparatuses by NOx adsorption are roughly classified into a fixed bed type and a moving bed type.

In the fixed bed method, a plurality of adsorbing devices are installed in parallel, the adsorbent adsorbs a predetermined amount of the target substance, and when the concentration of the target substance at the outlet of the adsorbing device reaches the limit, the device is switched and adsorption by NOx desorption is performed. Regenerate the agent. When handling a large amount of gas, the adsorbent filling amount can be kept low due to the gas flow resistance, so the frequency of switching the device increases. Therefore, depending on the time required for desorption and regeneration, the number of adsorbing devices installed in parallel increases, and the scale of the entire equipment becomes very large.

On the other hand, in the moving bed system, generally, the adsorbent is brought into countercurrent contact with the gas, and the adsorbent that adsorbs a large amount of the target substance is sequentially withdrawn from the adsorption section and desorption regeneration is performed, while the new adsorbent or desorbed regeneration adsorbent is sequentially activated. Fill the adsorption part. Therefore,
Since the adsorption device can be operated continuously and there is no need to switch the device, the equipment scale can be smaller than that of the fixed bed system.

As a conventional technique, a moving bed type NOx removal system is shown in FIG.

The NOx removal system will be described below with reference to FIG.

The dehumidification part (48) above the dehumidification tower (47) is filled with silica gel as a moisture adsorbent, and exhaust gas (NOx) introduced from the pipe line (41).
Moisture in (+ air + H ₂ O) is adsorbed to this. The absorbed moisture adsorbent moves downward by its own weight and enters the regeneration section (49). In the regeneration section (49), the moisture adsorbent is brought into contact with the regeneration dry gas introduced through the conduit (43) (using the outlet gas of the adsorption section (51)) to adsorb the adsorbed moisture. To remove from. In this way, the moisture adsorbent is regenerated, blown up by the dry gas, and circulated to the upper part of the dehumidification tower (48).

In this way, the moisture adsorbent silica gel repeats adsorption and desorption (regeneration) and circulates in the system. Exhaust gas introduced from the pipe (41) is dehumidified and passes through the pipe (42) to the adsorption tower (50).
Go to the upper adsorption part (51). The dry gas for regeneration from the pipe line (43) obtains water in the regeneration section (49) of the dehumidification tower (47) and is released into the atmosphere as purified gas (air + H ₂ O).

On the other hand, the adsorption part (51) of the adsorption tower (50) is filled with a NOx adsorbent, and NOx in the dry exhaust gas (air + NOx) from the dehumidification tower (47) is adsorbed by this. The adsorbent that has adsorbed NOx moves downward by its own weight and enters the desorption / regeneration section (52). In the desorption / regeneration section (52), the NOx adsorbent is heated to 400 ° C. by the heater (46), comes into contact with the dry-discharging gas described later, and is regenerated by desorbing the adsorbed NOx, and blown up by dry air. And is circulated to the upper part of the adsorption tower (5). The regeneration dry gas introduced from the pipe line (44) uses a part of the outlet gas of the adsorption section (51), and desorbs NOx from the adsorbent in the desorption / regeneration section (52),
It is taken out of the system as desorption gas from the pipe (45). The dry exhaust gas (NOx + air) introduced from the dehumidification section (48) to the adsorption section (51) through the pipe line (42) is denitrated in the adsorption section (51) to be purified dehumidified air, most of which is piped. It is introduced into the regeneration section (49) of the dehumidification tower (47) as a dry gas for regenerating the water adsorbent through the path (43), and the balance is used as a dry gas for regenerating the NOx adsorbent (5).
It is introduced to the desorption / reproduction section (52) of 0).

Since the desorbed gas taken out of the system through the pipe (45) contains NOx desorbed from the adsorbent, the NOx in the desorbed gas is absorbed by an alkaline aqueous solution or the like (wet absorption method) to remove the NOx. Proposed to be removed.
However, in this wet absorption method, NOx is accumulated in the absorbent as nitrates or nitrites,
Post-treatment (waste liquid treatment) or the like is required, which complicates the process and increases the treatment cost.

As a method of detoxifying this desorption gas and releasing it to the atmosphere, N
A method of treating an adsorbent having adsorbed Ox with air containing NH ₃ to regenerate it has already been proposed (Japanese Patent Laid-Open No. 63-1559).
33). In this method, NOx adsorbed on an adsorbent is reduced to harmless N ₂ and H ₂ O by a selective reduction reaction of NOx by NH ₃ , thereby desorbing NOx. In order to perform desorption / regeneration only by raising the temperature of the adsorbent that has adsorbed NOx, 40
Although the adsorbent must be heated to 0 ° C., when a zeolite carrying a copper salt having a denitration catalyst function is used as the NOx adsorbent, the adsorbent is 100 to 300 ° C. in NH ₃ -containing air (regeneration gas). It can be regenerated by contacting it at a low temperature (JP-A-63-13).
See 34461).

As described above, in the method using the NH ₃ -containing gas as the regeneration gas for the NOx adsorbent, the N 3 desorbed from the NOx adsorbent is used.
There is a possibility that the NH ₃ unreacted NOx and excess NH ₃ that did not react with one of the Ox is contained in the desorption gas. In order to prevent the desorption gas from containing an excessive amount of NH ₃ , it is necessary to accurately control the concentration of NH ₃ injected in the regeneration gas. On the other hand, if the amount of NH _{3 to be} injected is insufficient, the NOx adsorbent will be insufficiently regenerated, and it will be extremely difficult to operate the desorption / regeneration section of the NOx adsorbent.

Further, when the amount of injected NH ₃ in the regeneration gas is made excessively large in order to completely regenerate the NOx adsorbent, since the desorption gas contains an excessive amount of NH ₃ , this gas is further separated. It is necessary to lead it to a denitration reactor and detoxify it by denitration reaction of NOx and NH ₃ or oxidative decomposition reaction of NH ₃ .

In the moving bed type water adsorption / NOx adsorption device used in the NOx adsorption system of the above-mentioned Industrial Development Laboratory, when a large amount of gas is processed, the flow path is cut off in order to reduce the flow resistance of the gas. It is necessary to increase the area. On the other hand, in order to increase the adsorption efficiency, it is necessary to uniformly extract and fill the adsorbent particles in the channel cross-sectional direction, but this is extremely difficult. In the moving bed system, gravity is used to move the adsorbent, and the regenerated adsorption part is blown up by dry air from the lower part to the upper part of the adsorption tower, so the adsorbent itself wears, cracks, powders, and even the tower and lift pipes. In addition to the problem of wear on the inner surface, the structure of the tower is complicated and the operation of the device is not easy.

Thus, an object of the present invention is to provide a purification device for NOx-containing ventilation gas that overcomes the above-mentioned problems of the prior art, particularly a purification device for ventilation gas such as road tunnels.

[Means for Solving the Problems] A purifying device for ventilation gas such as a road tunnel according to the present invention is
In order to achieve the above object, an adsorption type dehumidifying device that dehumidifies the NOx-containing ventilation gas with a moisture adsorbent and regenerates the moisture adsorbent with the purified ventilation gas, and the NOx-containing ventilation gas after dehumidification to NOx It is equipped with an adsorption type denitrification device that denitrates with an adsorbent and regenerates a NOx adsorbent. In a purification device that is a rotary adsorption device that moves continuously, the rotary adsorption denitration device is a NOx adsorption zone, a preheating zone for preheating the unregenerated adsorbent in front of the adsorption zone in the rotation direction, and a rotation direction forward of the preheating zone. Adsorbent regeneration zone of
A cooling zone for cooling the regenerated adsorbent between the regeneration zone and the adsorption zone, a cooling gas pipeline for circulating the NOx adsorbent cooling gas to the cooling zone, and an NH through the regeneration zone and the preheating zone.
₃ A cooling gas pipe is provided with a gas circulation pipe for circulating the contained circulation gas for regeneration and a gas extraction pipe for extracting a part of the circulation gas for regeneration from the circulation pipe and then discharging it to the atmosphere through the denitration reactor. The passage is a pipe through which a part of the ventilation gas after purification passes.

In the ventilation gas purifying apparatus according to the present invention, both the adsorption-type dehumidification device and the adsorption-type denitration device have the above-mentioned rotary adsorption so that extraction, regeneration and filling of the adsorbent and the NOx adsorbent can be continuously performed. Is made with the device. This ventilation gas purification device obtains the same performance as that of the above-mentioned conventional purification device by a simpler method.It has a low gas flow resistance and a simple device structure. Device.

As the water adsorbent rotor of the adsorption type dehumidifier, a plurality of plate-shaped adsorbents made of silica gel are stacked with appropriate spacers, a plurality of flat plate adsorbents made of silica gel and a plurality of corrugated plate adsorbents are alternated. And a silica gel integrally molded into a honeycomb structure are used.

Further, as the NOx adsorbent rotor of the adsorption type denitration device, a plurality of plate-shaped adsorbents composed of an adsorbent in which a copper salt is supported on a zeolite carrier are stacked through an appropriate spacer, and a copper salt is supported on a zeolite carrier. A plurality of flat plate adsorbents and a plurality of corrugated plate adsorbents each composed of the above adsorbent are alternately stacked, or an adsorbent in which a copper salt is supported on a zeolite carrier integrally formed in a honeycomb structure is used. Zeolites may be synthetic or natural. As a preferable copper salt, copper chloride (CuCl ₂ ) or a double salt of copper chloride, for example, copper ammonium chloride (CuCl ₂ .2NH)
₄ Cl) or an ammine complex salt of copper chloride. Regarding the amount of copper salt supported, the amount of copper metal as copper metal was about 0.
It is preferably 1 to 20% by weight, more preferably about 0.5 to 10% by weight.

The cooling gas pipeline is connected to the downstream side of the denitration device of the ventilation gas pipeline so as to pass a part of the purified ventilation gas.

A gas cooling tower that cools the unpurified ventilation gas by contact with washing water may be provided in the upstream of the dehumidifying device. In this case, it is preferable to provide a water cooling tower in the downstream of the dehumidifying device to cool the washing water by partially evaporating the washing water by contact with the purified dry ventilation gas.

The dehumidification device preferably includes a first and second two-stage moisture absorbent rotor and a cooler for cooling the unpurified ventilation gas between the rotors. In this case, it is preferable that the first and second two-stage water absorbent rotors are rotated in opposite directions.

[Examples] The present invention will be specifically described with reference to the following examples.

Example 1 An example of a road tunnel ventilation gas purification system is shown in the flow chart of FIG.

In the same flow, the ventilation gas containing NOx is guided to the adsorption-type dehumidifier (1) by the ventilation gas pipe (8), the moisture in the ventilation gas is adsorbed and removed by the moisture adsorbent, and the dried ventilation gas is changed. can get. Then, this gas is an adsorption type denitration device.
Guided to (2), NOx in the gas is adsorbed and removed, and purified gas is obtained.

First, the structure of the adsorption type dehumidifier (1) will be described. The dehumidification device (1) used in the purification device of the present invention dehumidifies unpurified ventilation gas, and then uses the same amount of purified ventilation gas after denitration as the unpurified ventilation gas as the dry gas for regeneration. To regenerate the water adsorbent. Adsorption type dehumidifier
As the moisture adsorbent rotor (11) of (1), an adsorbent integrally formed of silica gel in a honeycomb structure is used. Then, looking at the water adsorbent rotor (11) in the axial direction, the rotor
The NOx-containing ventilation gas pipeline (8) is arranged so that the unpurified ventilation gas flows in the moisture adsorption zone communicating with the semicircular moisture adsorption portion (11a) of (11). Further, the purified ventilation gas pipe line (13) is arranged so that the purified ventilation gas flows into the regeneration zone communicating with the semicircular regeneration portion (11b) of the other half of the rotor (11). And the water adsorbent rotor
(11) is rotated in the direction of arrow (A).

Next, the structure of the adsorption type denitration device (2) will be described.
The denitrification device (2) used in the purification device of the present invention adsorbs and removes NOx in the dehumidified ventilation gas to obtain a purified dry ventilation gas, and at the same time, to recycle nitrogen gas containing NH ₃ for regeneration.
The Ox adsorbent is regenerated. Rotary adsorption type denitration equipment
(2) is between the NOx adsorption zone, the preheating zone for preheating the unregenerated adsorbent in front of the adsorption zone in the rotational direction, the adsorbent regeneration zone in the rotational direction forward of the preheating zone, and between the regeneration zone and the adsorption zone. And a cooling zone for cooling the regenerated adsorbent. As the NOx adsorbent rotor (12) of the denitration device (2), an adsorbent in which copper salt is supported on a synthetic zeolite support integrally formed in a honeycomb structure is used. The copper salt is ammonium copper chloride (CuCl ₂ .2NH ₄ Cl), and the supported amount of the copper salt is about 0.5 to 10 of the final adsorbent as copper metal.
% By weight.

Looking at the NOx adsorbent rotor (12) in the axial direction, the rotor (1
The ventilation gas pipeline (8) is arranged so that the ventilation gas after dehumidification flows into the NOx adsorption zone communicating with the semicircular NOx adsorption portion (12a) of 2). Further, the other semi-circular portion of the rotor (12) has three fan-shaped portions, that is, the NOx adsorption portion (12
a) A preheating part (12b) in the rotation direction front, an adsorption part (12c) in the rotation direction front thereof, and a cooling part (12) in the rotation direction front thereof.
d) and. A preheating zone for preheating the unregenerated adsorbent, a regeneration zone for adsorbent regeneration, and a cooling zone for cooling the regenerated adsorbent are in communication with each of these three fan-shaped portions. A cooling gas pipe (9) for circulating the NOx adsorbent cooling gas is arranged in the cooling zone, and the inlet end of the pipe (9) is in the NOx-containing ventilation gas pipe (8) downstream of the denitration device. Connected, the outlet end is connected to the dehumidification device upstream of the purified ventilation gas pipeline (13), and a part of the purified ventilation gas is passed through the cooling gas pipeline (9) as a NOx adsorbent cooling gas. It is done like this. A blower is installed in the cooling gas line (9) upstream of the cooling zone.
(18) is provided.

A gas circulation line (14) is arranged to circulate the NH ₃ -containing circulation gas for regeneration through the regeneration zone and the preheating zone. A heater (6) is provided in the circulation pipe (14) upstream of the regeneration zone.
Is equipped with a gas circulation line (14) in front of the heater (6).
And a heat exchanger (15) for exhaust heat recovery over the cooling gas line (9)
Is provided, and a blower (4) is provided downstream of the preheating zone of the gas circulation line (14). The NH ₃ supply unit (3) is connected to the NH ₃ supply line (1) in the heat exchanger upstream of the gas circulation line (14).
6) is arranged. And NOx adsorbent rotor (12)
Is rotated in the direction of arrow (B).

A gas extraction line (10) is arranged from the downstream side of the regeneration zone of the gas circulation line (14) to the upstream side of the dehumidifying device of the purified ventilation gas line (13), and the heater (7 ) And a denitration reactor (5). A part of the recycle gas for regeneration is extracted as a purge gas from the gas circulation line (14) by the gas extraction line (10), and then this gas is denitrated in the denitration reactor (5) and then purified ventilation gas. It is released into the atmosphere from the pipeline (13). From the downstream side of the heat exchanger of the cooling gas line (9) to the upstream side of the heat exchanger of the gas circulation line (14), the gas supply line (1
7) is arranged, and a heat exchanger (19) for recovering exhaust heat is provided along the pipe (17) and the downstream of the denitration reactor of the gas extraction pipe (10).

In the ventilation gas purifying device having the above-mentioned configuration, the ventilation gas containing NOx is adsorbed by the ventilation gas pipe (8).
Guided to the water adsorption zone of (1), the water adsorption agent rotor (1
The moisture in the ventilation gas is adsorbed and removed by the dry water adsorption section (11a) of 1), and a dry ventilation gas is obtained. Then, this gas is guided to the NOx adsorption zone of the adsorption type denitration device (2), and NOx in the ventilation gas is adsorbed and removed by the NOx adsorbent to obtain a purified gas. This purified dry gas is adsorbed by the purified ventilation gas line (13).
Guided to the regeneration zone (1), the wet-shaped regeneration part (11b) of the water adsorbent rotor (11) is dried and regenerated. Thus, the rotation of the water adsorbent rotor (11) continuously dehumidifies the NOx-containing ventilation gas and regenerates the water adsorbent.

On the other hand, in the NOx adsorption zone of the adsorption type denitration device (2), N
NOx in the ventilation gas is adsorbed and removed by the NOx adsorbing section (12a) of the Ox adsorbing rotor (12). The preheating part (12b) of the adsorbent rotor (12) that has adsorbed NOx is preheated with the NH ₃ -containing recycle gas which is circulated by the gas circulation pipe line (14) in the preheating zone, and the regenerating part (12c) is It is regenerated by the same gas in the regeneration zone. In the regeneration of the NOx adsorbent with the NH ₃ -containing gas, in order to make the adsorbed NOx in the adsorbent and NH ₃ react efficiently, the adsorbent and the recycle gas for regeneration are heated at an appropriate temperature (100 to 100 It is preferable to heat to (300 ° C.). NO
The cooling section (12d) of the adsorbent rotor (12) with desorbed x is cooled by the purified ventilation gas coming from the purified ventilation gas line (13) through the cooling line (9) in the cooling zone. Thus, rotation of the adsorbent rotor (12) causes NOx
Denitration of the contained ventilation gas, preheating of the NOx adsorbent, regeneration and cooling are continuously performed.

A part of the NH ₃ -containing recycle gas is used as a purge gas.
It is extracted from the gas circulation line (14) by the gas extraction line (10). Excess N contained in this purge gas
H ₃ and NO desorbed from the adsorbent without reacting
The x is reduced and harmless by the denitration reactor (5) installed downstream of the heater (7). Since the amount of purge gas processed in the denitration reactor (5) is very small, the denitration reactor (5) may be small in size, and the purge gas can be effectively and inexpensively rendered harmless.

Example 2 In this example, a gas cooling tower for cooling unpurified ventilation gas by contact with washing water is provided in the upstream of the adsorption type dehumidifier (1), and the dehumidifier (1) An example in which a water cooling tower for cooling the washing water by partially evaporating the washing water by contacting it with the purified dry ventilation gas is provided in the downstream.

In FIG. 2, a gas cooling tower (20) for cooling the unpurified ventilation gas by contact with washing water is provided in the upstream side of the dehumidification device of the unpurified ventilation gas pipeline (8), and the purified ventilation gas is supplied. Pipeline
In (13), a water cooling tower (21) that cools the washing water by partially evaporating the washing water in the gas cooling tower (20) by contact with the purified dry ventilation gas in the downstream of the dehumidifier (21). Is provided. The wash water is circulated between the gas cooling tower (20) and the water cooling tower (21) via the pumps (23) (24) and the wash water cooler (22).

The gas cooling tower (20) is a water washing tower, and by cooling the ventilation gas in the tower (20), the moisture content in the ventilation gas is reduced to the saturated steam concentration at that temperature. As a result, the load on the dehumidifying device (1) in the downstream is reduced, and energy saving is achieved. Further, the ventilation gas is cleaned by washing the ventilation gas with water in the gas cooling tower (20), and the SO _{2 in the} ventilation gas is removed.
The tower is absorbed and removed by water. In this way, water adsorbents and NOx
Part of dust and poisonous substances that affect the deterioration of the adsorbent are removed, and the downstream treatment is performed without any trouble.

In addition, the purified ventilation gas is still dry after the moisture adsorbent rotor is regenerated, so if this is introduced to the water cooling tower (21) and brought into contact with the wash water in the gas cooling tower (20), the ventilation gas Absorbs up to the saturated vapor pressure corresponding to the gas temperature in the water cooling tower (21), and as a result, this wash water partially evaporates, and the evaporation latent heat is removed to cool it. Thus, by using the gas cooling tower (20) and the water cooling tower (21) together, the wash water cooler (2
Energy consumption of 2) is reduced and energy saving is achieved.

In FIG. 2, the adsorption-type dehumidifying device (1) has a non-purified structure between the first and second two-stage water absorbent rotors (11) and (11 ') and these rotors (11) and (11'). Clarifier for ventilation gas cooling (2
5) and heater (26). Adsorption type dehumidifier
Ventilation gas line containing NOx from (1) to adsorption type denitration device (2)
A blower (28) is provided in (8), and a heater (29) is provided in the purified ventilation gas pipe line (13) from the adsorption type denitration device (2) to the adsorption type dehumidification device (1). There is. Flush Water Cooler (22)
And the heater (26) are connected by the heat pump (27), the cooler (25) and the heater (29) are connected by the heat pump (30),
Energy saving is also achieved by these connections. The other structure is the same as that of the first embodiment.

Example 3 In this example, the adsorption-type dehumidification device (1) is
Between the two-stage water absorbent rotors (11) (11 ') and these rotors (11) (11') for cooling the unpurified ventilation gas (2
5) is provided, and the first and second two-stage water absorbent rotors (11) and (11 ') are rotated in directions opposite to each other.

When dehumidifying exhaust gas using a moisture adsorbent integrally formed of silica gel in a honeycomb structure, the moisture adsorbent generates heat of adsorption due to adsorption of moisture. Therefore, in the moisture adsorbing portion, both the temperature of the water adsorbent and the temperature of the gas become higher from the gas inlet side to the gas outlet side. Since the adsorption performance of the water adsorbent decreases as the temperature increases, the water adsorbent does not function effectively on the outlet side of the water adsorbent. Therefore, as shown in FIGS. 2 and 3, between the first and second two-stage water absorbent rotors (11) and (11 ′) and these rotors (11) and (11 ′) are not cleaned. An adsorption type dehumidifier equipped with a cooler (25) for cooling ventilation gas becomes effective. That is, the first stage rotor (11) dehumidifies the ventilation gas,
Second after the heated ventilation gas is cooled by the cooler (25)
By being guided to the rotor (11 ′) and further dehumidified by the rotor (11 ′), a higher degree of dehumidification becomes possible.

FIG. 3 shows this embodiment, and FIG. 4 shows a comparative example. In the comparative example, a 350 × 400 L silica gel water absorbent rotor (11) was rotated at 8 revolutions / hour, and the gas temperature was 8.5 ° C. and the humidity was 5.6 g / kg-untreated gas of dry air (180 Nm). ³ / h) is passed through the moisture adsorption section, the dehumidified gas is heated to 40.2 ° C. by the heater (29), and then introduced into the regeneration section. In this case, the gas leaving the moisture adsorption section is dehumidified to a moisture content of 0.15 g / kg, and the gas temperature is 2
The temperature is raised to 7.7 ° C.

On the other hand, in this example, the 350 × 200 L first-stage and second-stage rotors (11) and (11 ′) were respectively rotated in opposite directions at 8 revolutions / hour, and the gas temperature was 8.5 ° C. and the moisture content was 5 ° C. .6
The untreated gas (180 Nm ³ / h) of g / kg-dry air was passed through, and the gas leaving the moisture adsorbing section was cooled by the cooler (25).
After cooling to 5 ° C, it is passed through the second stage rotor (11 '). The gas dehumidified in the water adsorption part of the rotor (11 ') is heated to 34.4 ° C by the heater (29),
It is guided to the regeneration section of the second stage rotor (11 '). The gas discharged from the second stage rotor (11 ') is further heated by the heater (26).
After being heated to 0.3 ° C., it is introduced into the first stage rotor (11). In this case, the gas exiting the water adsorption section of the first stage rotor (11) is dehumidified to 0.16 g / kg, and the second stage rotor (1
The gas leaving the water adsorption section 1 ') was dehumidified to a moisture content of 0.05 g / kg. In this way, the dehumidifying rotor is divided into two, a cooler is provided in the middle part, and the second-stage rotor (11 ') is effectively functioned, whereby a high degree of dehumidification is possible.

Also, the first stage rotor (11) of this embodiment shown in FIG.
The dehumidifying performance of the only one is almost the same as the dehumidifying performance of the comparative example shown in FIG. From this, it can be seen that in the comparative example, the rear half of the downstream side of the moisture adsorbing portion does not function for dehumidification at all.

Example 4 This example concerns the direction of rotation of the rotor.

It is preferable to rotate the first-stage rotor (11) and the second-stage rotor (11 ') in opposite directions.

In the flow shown in FIG. 3, the first-stage rotor (11) and the second-stage rotor (11 ') are rotated in opposite directions, respectively.
When the rotating directions are the same, the dehumidifying performance is slightly lowered.

FIG. 5 shows a case of reverse rotation, and FIG. 6 shows a case of same direction rotation as a comparative example. As shown in FIGS. 5 and 6, after the gas flow passes through the first-stage rotor (11), there is no turbulence of the gas even in the middle portion, and the gas flows through the second-stage rotor (11 ′) as it is. Think

The portion of the first stage rotor (11) where the gas (b) flows absorbs more moisture than the portion where the gas (a) flows. Therefore, looking at the gas after passing through the moisture adsorption part of the first stage rotor (11), gas (a) is the gas
Dehumidified more than (b).

As shown in FIG. 6, when the second-stage rotor (11 ') rotates in the same direction as the first-stage rotor (11), the gas (a ) Is a dehumidifying agent immediately after regeneration, so gas (a) is further dehumidified, whereas gas (b) is absorbing moisture, so gas (b) is Almost no dehumidification with the two-stage rotor (11 ').

On the other hand, as shown in FIG. 5, the second stage rotor (1
When the 1 ') rotates in the opposite direction to the first-stage rotor (11), the gas in the water adsorption part of the second-stage rotor (11')
Since the part where (b) flows is the dehumidifying agent immediately after regeneration,
(b) is fully dehumidified. On the other hand, since the portion where the gas (a) flows absorbs moisture, the gas (a) is not significantly dehumidified. However, the first stage rotor (11) and the second stage rotor (1
As a result of combining 1 '), both gas (a) and gas (b) are dehumidified to the same extent.

For the above reason, it is considered that the dehumidification performance is improved by rotating the first-stage rotor (11) and the second-stage rotor (11 ') in opposite directions.

As a comparative example, FIG. 7 shows the results of dehumidification when the first-stage rotor (11) and the second-stage rotor (11 ') were rotated in the same direction. By comparing the comparative example of FIG. 7 with the embodiment of FIG.
It turns out that it is preferable to rotate in the opposite direction.

Example 5 This example relates to the number of rotations of the rotor, in other words, the feed rate of the dehumidifying agent.

In order to make the dehumidification performance of the 2nd stage rotor (11 ') function effectively, the rotation speed, length, honeycomb pitch, etc. of the 1st stage rotor (11) are changed to control the dehumidifying agent supply speed. Preferably.

As can be seen in Fig. 3, the rotation speed is the first stage rotor (11).
When both the second stage rotor (11 ') and the second stage rotor (11') are 8 revolutions / hour, about 98% of the amount of water dehumidified in the dehumidifying device is dehumidified by the first stage rotor (11), and the remaining about 2% is left. Dehumidified by the 2nd stage rotor (11 '). That is, almost the entire amount is dehumidified by the first-stage rotor (11), and the dehumidifying ability of the second-stage rotor (11 ') is hardly utilized. Therefore, in order to effectively utilize the second-stage rotor (11 ′), the comprehensive dehumidification performance by the two-stage rotor was examined under the condition that the dehumidification ability of the first-stage rotor (11) was reduced. .

In order to reduce the dehumidification performance of the first-stage rotor (11), as shown in FIG. 8, the rotation speed of the first-stage rotor (11) is reduced to 2 revolutions / h, and the supply rate of the dehumidifying agent is reduced. I made it to 1/4. The reached moisture concentration by the two-stage rotor is 0.055 g / kg-dry air, which is almost the same as the case of the embodiment of FIG. From this, it was found that even if the dehumidification performance of the first-stage rotor (11) was reduced, the reached moisture concentration by the second-stage rotor was not adversely affected.

FIG. 9 shows a first stage rotor (11) as compared with the embodiment of FIG.
Rotation of 4 rotations / h, conversely the 2nd stage rotor (11 ')
The case where the number of rotations of is increased to 16 rotations / h is shown. The ultimate moisture concentration in this case is 0.015 g / kg-dry air,
A high degree of dehumidification is possible by effectively utilizing the dehumidification capacity of the second stage rotor (11 ').

As a method for reducing the supply rate of the dehumidifying agent in the first stage rotor (11), a method of shortening the rotor length without changing the rotation speed of the rotor or a method of roughening the pitch of the honeycomb There are ways. According to these methods, the pressure loss of the gas passing through the rotor can be reduced, and energy can be saved by reducing the power consumption of the blower.

[Advantages of the Invention] According to the ventilation gas purification device of the present invention, the use of the rotary adsorption device enables the extraction, regeneration and filling of the water adsorbent and the NOx adsorbent to be continuously performed.

Further, in the regeneration of the NOx adsorbent according to the above-mentioned conventional technique, a low concentration of NH ₃ is accurately mixed and dispersed in the circulation gas for regeneration, and the amount thereof corresponds to the adsorbed NOx in the adsorbent, that is, reduction removal. Must be sufficient and necessary. This amount cannot be controlled unless the amount of adsorbed NOx in the adsorbent is accurately measured, but it is actually impossible to continuously measure NOx in the adsorbent that is a solid. Therefore, the regeneration of the NOx adsorbent according to the prior art is practically performed by leakage of excess NH ₃ and injection of NH ₃
It is highly likely that either the result of incomplete adsorbent regeneration due to a lack of volume.

On the other hand, according to the device of the present invention, excess NH ₃ can be made to exist in the regeneration part of the NOx adsorbent, and as a result, by supplying a sufficient amount of NH ₃ to the regeneration part, the NOx adsorbent The adsorbed NOx can be more completely reduced and removed, and the NOx adsorbent can be completely regenerated. Therefore, it not required precise control of the NH ₃ injection. Thus, the gas purification device according to the present invention is a very practical and economical device.

Further, since a part of the ventilation gas after purification is passed through the cooling gas pipe line through which the NOx adsorbent cooling gas is passed through the cooling zone, the cooling portion of the NOx adsorbent rotor from which NOx has been desorbed has been purified. It can be cooled effectively by ventilation gas.

If a gas cooling tower that cools the unpurified ventilation gas by contact with washing water is installed in the upstream of the dehumidifier, the ventilation gas in the gas cooling tower cools the moisture in the ventilation gas. The saturated water vapor concentration at that temperature is reduced. As a result, the load on the downstream dehumidifier is reduced,
Energy saving is achieved. In addition, the ventilation gas is washed with water in the gas cooling tower to remove dust, and
SO _{2 and the} like in the ventilation gas are absorbed and removed by water. In this way, dust and poisoning substances that affect the deterioration of the moisture adsorbent and the NOx adsorbent are partially removed, and the downstream treatment is performed without any trouble.

Further, when the dehumidifying device is provided with the first and second two-stage moisture absorbent rotors and the cooler for cooling the unpurified ventilation gas between these rotors, the ventilation gas of the first stage rotor Dehumidification is performed, and the heated ventilation gas is cooled by the cooler and then guided to the second-stage rotor, where it is further dehumidified, thereby enabling a higher degree of dehumidification.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1, FIG. 2, FIG. 3, FIG. 5, FIG. 7, FIG. 8 and FIG. 9 are flow sheets showing an embodiment of the present invention. 4 and 6 are flow sheets showing a comparative example. FIG. 10 is a flow sheet showing a conventional technique. (1) …… Adsorption-type dehumidification equipment, (2) …… Adsorption-type denitration equipment, (3)
…… NH ₃ supply device, (4) …… blower, (5) …… denitration reactor, (6) …… heater, (7) …… heater, (8) …… N
Ox-containing ventilation gas pipeline, (9) …… cooling gas pipeline, (10)…
… Gas extraction line, (11) …… Moisture absorbent rotor, (1
1a) …… Moisture adsorption part, (11b) …… Regeneration part, (12) …… NOx
Adsorbent rotor, (12a) …… NOx adsorption section, (12b) …… Preheating section, (12c) …… Regeneration section, (12d) …… Cooling section, (13) …… Cleaned ventilation gas pipeline, ( 14) …… Gas circulation line, (15) ……
Heat exchanger, (16) …… NH ₃ supply line, (17) …… Gas supply line, (18) …… Blower, (19) …… Heat exchanger, (20) ……
Gas cooling tower, (21) …… water cooling tower, (22) …… wash water cooler, (23) …… pump, (24) …… pump, (25) …… cooler, (26) …… heater, (27) …… Heat pump, (28)…
… Blower, (29) …… heater, (30) …… heat pump.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Shigenori Onizuka 1-6-14 Edobori, Nishi-ku, Osaka City, Osaka Prefecture Hitachi Shipbuilding Co., Ltd. (72) Shuji Kobayashi 1-6-14 Edobori, Nishi-ku, Osaka City, Osaka Prefecture Inside Hitachi Shipbuilding Co., Ltd. (56) Reference JP-A-2-26616 (JP, A)

Claims (5)

[Claims] 1. An adsorption type dehumidifying device for dehumidifying a NOx-containing ventilation gas with a moisture adsorbent and regenerating the moisture adsorbent with the purified ventilation gas, and a NOx-containing ventilation gas after dehumidification with a NOx adsorbent. An adsorption type denitration device that denitrates and regenerates the NOx adsorbent is provided. The adsorption type dehumidification device and the adsorption type denitration device continuously move the moisture adsorbent rotor and the NOx adsorbent rotor in a direction perpendicular to the gas flow. In a purification device that is a rotary adsorption device, the rotary adsorption denitration device is a NOx adsorption zone, a preheating zone for preheating unregenerated adsorbent in front of the adsorption zone in the rotational direction, and an adsorbent in front of the preheating zone in the rotational direction. Play zone,
A cooling zone for cooling the regenerated adsorbent between the regeneration zone and the adsorption zone, a cooling gas pipeline for circulating the NOx adsorbent cooling gas to the cooling zone, and an NH through the regeneration zone and the preheating zone.
₃ A cooling gas pipe is provided with a gas circulation pipe for circulating the contained circulation gas for regeneration and a gas extraction pipe for extracting a part of the circulation gas for regeneration from the circulation pipe and then discharging it to the atmosphere through the denitration reactor. A device for purifying ventilation gas such as road tunnels, characterized in that the passage is a pipe line through which part of the ventilation gas after purification passes. 2. An adsorption-type dehumidifying device for dehumidifying a NOx-containing ventilation gas with a moisture adsorbent and regenerating the adsorbent with the purified ventilation gas, and a NOx-containing ventilation gas after dehumidification with a NOx adsorbent. An adsorption type denitration device that denitrates and regenerates the NOx adsorbent is provided. The adsorption type dehumidification device and the adsorption type denitration device continuously move the moisture adsorbent rotor and the NOx adsorbent rotor in a direction perpendicular to the gas flow. In a purification device that is a rotary adsorption device, the rotary adsorption denitration device is a NOx adsorption zone, a preheating zone for preheating unregenerated adsorbent in front of the adsorption zone in the rotational direction, and an adsorbent in front of the preheating zone in the rotational direction. Play zone,
A cooling zone for cooling the regenerated adsorbent between the regeneration zone and the adsorption zone, a cooling gas pipeline for circulating the NOx adsorbent cooling gas to the cooling zone, and an NH through the regeneration zone and the preheating zone.
_A dehumidification device is provided with a gas circulation pipe for circulating the ₃ contained regeneration circulation gas and a gas extraction pipe for extracting a part of the regeneration circulation gas from the circulation pipe and then discharging it to the atmosphere through the denitration reactor. A gas cooling tower that cools unpurified ventilation gas by contacting it with washing water is provided in the upstream of the above. 3. A water cooling tower, which cools the washing water by partially evaporating the washing water used in claim (2) in contact with the purified dry ventilation gas, in the downstream of the dehumidifying device. The purifying device according to claim 2, which is provided. 4. An adsorption type dehumidifying device for dehumidifying NOx-containing ventilation gas with a moisture adsorbent and regenerating the moisture adsorbent with the purified ventilation gas, and a NOx-containing ventilation gas after dehumidification with a NOx adsorbent. An adsorption type denitration device that denitrates and regenerates the NOx adsorbent is provided. The adsorption type dehumidification device and the adsorption type denitration device continuously move the moisture adsorbent rotor and the NOx adsorbent rotor in a direction perpendicular to the gas flow. In a purification device that is a rotary adsorption device, the rotary adsorption denitration device is a NOx adsorption zone, a preheating zone for preheating unregenerated adsorbent in front of the adsorption zone in the rotational direction, and an adsorbent in front of the preheating zone in the rotational direction. Play zone,
A cooling zone for cooling the regenerated adsorbent between the regeneration zone and the adsorption zone, a cooling gas pipeline for circulating the NOx adsorbent cooling gas to the cooling zone, and an NH through the regeneration zone and the preheating zone.
_A dehumidification device is provided with a gas circulation pipe for circulating the ₃ contained regeneration circulation gas and a gas extraction pipe for extracting a part of the regeneration circulation gas from the circulation pipe and then discharging it to the atmosphere through the denitration reactor. Is equipped with a first and second two-stage moisture absorbent rotor and a cooler for cooling unpurified ventilation gas between these rotors. A ventilation gas purification device for a road tunnel or the like. 5. The purifier according to claim 4, wherein the first and second two-stage water absorbent rotors are rotated in opposite directions.