JP4979522B2 - Organic solvent gas processing equipment - Google Patents

Description

  The present invention relates to an organic solvent gas treatment apparatus that removes VOC from a gas containing an organic solvent (hereinafter referred to as “VOC”) using an adsorption rotor having an adsorbent such as zeolite, for example, and has a particularly high adsorption efficiency. In addition, the present invention relates to an apparatus that can reduce moisture in the VOC gas from which the VOC once adsorbed by the adsorption rotor is desorbed.

  An organic solvent gas processing apparatus using an adsorption rotor having an adsorbent such as zeolite can obtain a VOC-concentrated gas by the adsorption / desorption process of VOC, and this is the target gas for VOC recovery processing. In recent years, it has been rapidly popularized because the energy saving effect can be enhanced by reducing the amount of energy and reducing the energy associated with the treatment.

  A general VOC gas treatment device that is currently popular corrugates non-combustible paper such as ceramic paper to form a honeycomb-like rotor, and this honeycomb rotor carries an adsorbent such as hydrophobic zeolite. The adsorption / concentration rotor is used.

  And about the concentrated VOC gas, in addition to being incinerated by the combustion device, the VOC in the gas may be condensed and recovered. If this method of condensing and recovering is used, the organic solvent can be reused, which is preferable from the viewpoint of resource saving.

However, when water vapor is contained in the VOC gas, this water vapor also becomes water by condensation. Since the latent heat of water is large, extra energy is required to condense water when processing the VOC gas. In addition, when the VOC is hydrophilic, the condensed VOC and water are mixed, and even when the VOC is not hydrophilic, small water droplets float in the VOC, making it difficult to reuse the VOC. There were problems such as becoming.
As a technique for solving such a problem of the VOC gas processing apparatus, for example, there is one disclosed in Patent Document 1 below.
JP 2007-044595 A

  The one disclosed in Patent Document 1 condenses and collects VOC from a gas containing desorbed VOC by providing dehumidifying means on the desorption inlet side and using dry air dehumidified as desorption air of the adsorption rotor. It is designed to make it difficult for water to form.

  However, the thing of patent document 1 raises the temperature of an adsorption | suction rotor when an adsorption | suction rotor passes a desorption zone. When the temperature of the adsorption rotor is high, the adsorption performance cannot be sufficiently exhibited, and there is a problem that it becomes impossible to cope with a dilute VOC gas.

  As a means for lowering the temperature of the adsorption rotor that has exited the desorption zone, it can be considered to provide a purge zone between the desorption zone and the adsorption zone. However, the patent document 1 does not describe how to use the purge zone. Even if the technology of the purge zone is applied to the one described in patent document 1, the purge air is not dehumidified by the dehumidifying means. There is a problem that the cooling effect in the purge zone cannot be sufficiently exhibited when the temperature is raised by the heat of adsorption and the air whose temperature has increased passes through the purge zone. In addition, the temperature of the outside air is lower than that of the dehumidified air, and if it is purged with the outside air, the cooling effect will be somewhat higher, but the outside air in the summer may exceed 40 ° C in some cases. There is a problem that cannot be obtained.

  The present invention was made to solve the above problems, and can reliably adsorb and recover the organic solvent in the organic solvent gas generated from the factory, etc., and can reduce the moisture contained in the recovered organic solvent, An object of the present invention is to provide an organic solvent gas processing apparatus in which the organic solvent can be easily reused.

The present invention includes an adsorption rotor having an adsorbent, and the adsorption rotor is divided into at least an adsorption zone, a desorption zone, and a purge zone, and an organic solvent gas generated from a predetermined generation source is passed through the adsorption zone, while in the atmosphere. after passing the air for desorption is introduced into the cooling dehumidifying unit from, through a purge zone is desorbed air that has passed through the purge zone that was to pass heated by the heater to the desorbing zone. According to the present invention, the air sent to the purge zone has the effect that the humidity can be lowered and the temperature can be lowered.

  In the present invention, dry air is used as air for desorbing the adsorption rotor, and a purge zone is provided for cooling the rotor that has exited the desorption zone, and the air entering the purge zone is dehumidified via a cooling dehumidifying means. The temperature of the air entering the purge zone is low, the effect of the purge zone can be fully exerted, and the VOC removal efficiency is increased.

  Then, when the air that has passed through the cooling and dehumidifying means is passed through the dehumidifying rotor and further dehumidified, the dehumidifying efficiency is increased by passing the cooled air through the adsorption zone of the dehumidifying rotor. The amount of water contained in the desorption air is further reduced.

(First embodiment of the present invention)
Hereinafter, the organic solvent gas processing apparatus according to the first embodiment of the present invention will be described in detail with reference to FIG. The adsorption rotor 1 has a VOC adsorbent such as hydrophobic zeolite and is divided into an adsorption zone 2, a purge zone 3 and a desorption zone 4. Of course, the suction rotor 1 is rotated by a motor (not shown). VOC gas, which is a mixture of VOC vapor and air, is sent to the adsorption zone 2. The purified air leaving the adsorption zone 2 is released to the atmosphere.

  The cooling and dehumidifying means 5 is a known device that cools the passing air and dehumidifies the moisture by condensation, such as an evaporator or a cold water coil, and detailed description thereof is omitted. Desorption air is introduced into the cooling and dehumidifying means 5, and the air leaving the cooling and dehumidifying means 5 enters the purge zone 3 of the adsorption rotor 1.

  The air leaving the purge zone 3 enters the heater 6 and is heated to enter the desorption zone 4 of the adsorption rotor 1. The VOC gas exiting the desorption zone 4 enters the condenser 7, and the VOC gas exiting the condenser 7 is returned to the adsorption zone 2.

  Next, the operation of the organic solvent gas processing apparatus according to the first embodiment of the present invention will be described. When the VOC gas passes through the adsorption zone 2, for example, 98% of the VOC in the VOC gas is adsorbed by the adsorbent and becomes purified air.

  When the desorption air introduced from the atmosphere passes through the cooling and dehumidifying means 5, the moisture is condensed to lower the absolute humidity. Then, the desorption air in the low temperature drying state that has exited the cooling and dehumidifying means 5 passes through the purge zone 3 to cool the adsorption rotor 1. The cooled adsorption rotor 1 moves to the adsorption zone 2 with the temperature lowered.

  The temperature of the desorption air that has passed through the purge zone 3 rises, and further increases by passing through the heater 6, and enters the desorption zone 4 as high-temperature desorption air, for example, about 140 ° C. The adsorption rotor 1 is heated by the desorption air, and the adsorbed VOC is desorbed.

  As described above, the desorbed adsorption rotor 1 is cooled in the purge zone 3. The VOC gas exiting the desorption zone 4 is in a state of being concentrated at a ratio of (passing gas amount in the adsorption zone 2) / (passing gas amount in the desorption zone 4).

  This high-concentration VOC gas enters the condenser 7 and is cooled to condense the VOC. The condensed VOC is led to the storage tank 8. The VOC gas from which most of the VOC has been removed by the condenser 7 is returned to the adsorption zone 2 again, and the above process is repeated.

  The organic solvent gas processing apparatus according to the present embodiment effectively cools the adsorption rotor 1 in the purge zone 3 by creating the low-temperature dry air by the cooling and dehumidifying means 5 as described above and guiding it to the purge zone. Adsorption can be promoted.

(Second embodiment of the present invention)
Next, an organic solvent gas processing apparatus according to the second embodiment of the present invention shown in FIG. 2 will be described. Hereinafter, the same components as those in the first embodiment will be given the same numbers, and redundant description will not be given to avoid redundancy.

  The organic solvent gas processing apparatus according to the second embodiment includes a dehumidifying rotor 9 and a heater 12 having a dehumidifying agent in addition to the configuration of the first embodiment. The dehumidifying rotor 9 is divided into an adsorption zone 10 and a desorption zone 11. The heater 12 is for desorbing moisture adsorbed on the dehumidifying rotor 9.

  The organic solvent gas processing apparatus according to the second embodiment performs the following operation in addition to the operation in the first embodiment. That is, when the desorption air introduced from the atmosphere passes through the cooling and dehumidifying means 5, the moisture is condensed to lower the absolute humidity, and subsequently passes through the adsorption zone 10 of the dehumidifying rotor 9, thereby further It becomes dry air.

  Here, when the air passes through the adsorption zone 10 and is dehumidified, the temperature generally increases due to the heat of adsorption. In the present embodiment, the air passing through the adsorption zone 10 is dehumidified to some extent by the cooling dehumidifying means 5. Since the humidity is reduced, the heat of adsorption is small. In this way, the air having a very low humidity enters the purge zone 3 of the adsorption rotor 1.

  The desorption air exiting the purge zone 3 is heated by the heater 6 and enters the desorption zone 4 as in the first embodiment. However, since the humidity of the desorption air is extremely low, the desorption air exits the desorption zone 4. When the high-concentration VOC gas is condensed by the condenser 7, the moisture is hardly condensed.

  On the other hand, the air introduced from the atmosphere is heated by the heater 12, and the heated desorption air passes through the desorption zone 11 of the dehumidification rotor 9, so that moisture adsorbed on the dehumidification rotor 9 is desorbed, and the atmosphere Is released.

  As described above, the organic solvent gas processing apparatus according to the second embodiment is condensed in the condenser 7 by making the moisture contained in the VOC gas exiting the desorption zone 4 of the adsorption rotor 1 extremely small. Thus, the water contained in the VOC stored in the storage tank 8 can be remarkably reduced, and the VOC can be easily reused.

  In the second embodiment, the dehumidification rotor 9 is not provided with a purge zone. However, when it is necessary to obtain air with a lower dew point, the dehumidification rotor 9 can be provided with a purge zone.

  In each of the first and second embodiments, the VOC gas exiting the desorption zone 4 of the adsorption rotor 1 is cooled and condensed by the condenser 7 as it is, and the VOC is recovered. As a third embodiment, the VOC gas exiting the desorption zone 4 of the adsorption rotor 1 is once adsorbed by an adsorbent that hardly adsorbs moisture, such as activated carbon, and then nitrogen gas produced by liquefaction separation of air. VOC adsorption / desorption means having a mechanism such as desorption with a high-temperature gas having a low moisture content, etc. can be used, and the VOC can be recovered by condensing the desorbed VOC gas in the condenser 7. The water adsorbed by the adsorbent along with the VOC can be reduced, and the high-temperature nitrogen gas that desorbs a very small amount of water from the VOC is produced by the difference in physical properties during the production process. Since the water content in the VOC gas after desorption is greatly reduced, the amount of water in the VOC after the VOC recovery process can be further reduced, and the condensation in the condenser In addition to reducing the energy consumption associated with this, not only can the efficiency of the entire apparatus be improved, but also the use of the VOC after recovery can be facilitated.

  The organic solvent gas treatment device of the present invention is for recovering and reusing the organic solvent in the organic solvent gas generated from factories, etc., so that the effect of the purge zone can be fully exerted and the organic solvent can be removed. It is extremely useful in that the efficiency can be increased, the water content in the recovered organic solvent is small, and the organic solvent can be easily reused.

It is a flowchart which shows the organic-solvent gas processing apparatus which concerns on the 1st Embodiment of this invention. It is a flowchart which shows the organic-solvent gas processing apparatus which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Adsorption rotor 2 Adsorption zone 3 Purge zone 4 Desorption zone 5 Cooling dehumidification means 6 Heater 7 Condenser 8 Storage tank 9 Dehumidification rotor 10 Adsorption zone 11 Desorption zone 12 Heater

Claims (5)

In an organic solvent gas processing apparatus equipped with an adsorption rotor having an adsorbent,
The adsorption rotor is divided into at least an organic solvent adsorption zone, an organic solvent desorption zone, and a rotor cooling purge zone;
While passing the organic solvent gas generated from a predetermined source through the adsorption zone, the organic solvent is adsorbed on the adsorbent,
Air introduced from the atmosphere as desorption of the organic solvent is passed through a predetermined cooling and dehumidifying means in advance , and the cooled and dehumidified desorption air that has exited from the cooling and dehumidifying means is passed through the purge zone and purged. the desorption air passing through the zone is heated by a heater, an organic solvent gas treatment device, characterized in that passed through the desorbing zone.
In the organic solvent gas processing apparatus according to claim 1,
A dehumidifying rotor having a dehumidifying agent,
The organic solvent gas processing apparatus, wherein the desorption air that has passed through the cooling and dehumidifying means passes through the adsorption zone of the dehumidifying rotor and then passes through the purge zone. In the organic solvent gas processing apparatus according to claim 1 or 2,
A condenser that exits the desorption zone of the adsorption rotor, cools the gas containing the desorbed organic solvent, and condenses the organic solvent in the gas;
An organic solvent gas processing apparatus, wherein the condensed organic solvent is separated and the gas exiting the condenser is refluxed to the adsorption zone of the adsorption rotor. In the organic solvent gas processing apparatus according to claim 3,
The gas from the desorption zone of the adsorption rotor is caused to flow on the upstream side of the condenser, and the organic solvent in the gas is adsorbed to a predetermined adsorbent having a low moisture adsorption force, and at a high temperature with a low moisture content. An organic solvent adsorption / desorption means for desorbing the organic solvent from the adsorbent with gas,
The organic solvent gas processing apparatus, wherein the condenser cools the gas emitted from the organic solvent adsorption / desorption means to condense the organic solvent. In the organic solvent gas processing apparatus according to claim 4,
An organic solvent gas processing apparatus, wherein the adsorbent in the organic solvent adsorption / desorption means is activated carbon, and nitrogen gas produced by liquefaction separation of air is used as a high temperature gas for desorbing the organic solvent.

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