JP7053079B1 - Gas processing equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas treatment apparatus capable of preventing the generation of a liquid substance on the regeneration outlet side by a simple method. SOLUTION: In the gas treatment apparatus of the present invention, the regeneration outlet temperature is set to 60 to 120 ° C, more preferably 70 to 120 ° C. by adjusting the rotation speed, bypassing the heating gas, burying the heating apparatus on the regeneration outlet side, and the like. By performing the increased regeneration temperature raising operation, it is possible to prevent the generation of liquid matter at the regeneration outlet. [Selection diagram] Fig. 1

Description

The present invention relates to a technique for preventing the generation of a liquid substance on the regeneration outlet side of a gas treatment apparatus.

In recent years, air pollution has become a problem on a global scale, and VOCs such as toluene (volatile organic compounds, hereinafter referred to as "VOCs") are one of them, and are used in painting processes and printing factories. It occurs a lot.

Exhaust gas treatment equipment (combustion equipment and recovery equipment) containing VOCs has a problem that not only the equipment becomes very large when the treatment air volume becomes large, but also a huge running cost is required. On the other hand, the VOC concentrator as the pre-stage equipment of the exhaust gas treatment equipment can concentrate and recover low concentration and large air volume VOC exhaust gas to high concentration and small air volume, so the equipment cost and running cost of the entire treatment equipment can be significantly reduced. It can be reduced and efficient VOC processing can be realized.

As one of the VOC concentrators, there is a honeycomb rotor type VOC concentrator that selectively adsorbs and concentrates VOCs in exhaust gas. Normally, the VOC adsorption honeycomb rotor is supported by hydrophobic zeolite and is regenerated by a heating gas at around 200 ° C. (hereinafter, the temperature is referred to as "Celsius"), so that adsorption and regeneration can be repeated. It is possible. However, in the VOC treatment mode in which the VOC is removed from the gas to be treated (a gas to be treated with a low concentration and a large air volume is passed through the treatment zone of the honeycomb rotor, and the contained VOC is adsorbed on the honeycomb to be a clean gas, and in the regeneration zone, VOCs with a high boiling point above the temperature of the heating gas (for example, 200 ° C or higher) are regenerated in the passage of a heating gas at around 200 ° C to separate the VOC from the honeycomb and convert it into a concentrated gas with high concentration and small air volume. Since it is not separated from the honeycomb rotor in the zone, it is accumulated in the honeycomb rotor with the operation of the VOC concentrator, and the capacity of the honeycomb rotor is reduced. Therefore, in Patent Document 1, a heated gas is placed in the regeneration zone at a high temperature regeneration mode (for example, 300 ° C.) at which the VOC having a high boiling point accumulated in the honeycomb rotor is separated from the honeycomb rotor at a temperature higher than the regeneration temperature in the VOC processing mode. Disclosed is a VOC removal technique for performing activation treatment by passing VOCs having a high boiling point accumulated in the honeycomb rotor and separating them from the honeycomb rotor).

Utility Model Registration No. 32197662

By the way, under conditions where the regeneration outlet gas has high humidity, such as when the gas to be treated has high humidity or when the regeneration gas has high humidity due to regeneration circulation, if the regeneration outlet temperature is low, it will be high in the casing on the regeneration outlet side. Moisture in humidity may condense and condense. This can occur not only in VOC concentrators but also in desiccant dehumidifiers and other gas treatment devices. In the case of the VOC concentrator, when the water-soluble high boiling point VOC is contained in the gas to be treated, the water-soluble high boiling point VOC concentrated and desorbed on the regeneration outlet side is dissolved in the condensed water generated on the regeneration outlet side. , Drying and condensation are repeated according to the temperature change of the regeneration outlet gas, and the high boiling point VOC is concentrated, and a brown to black tar-like liquid substance may be produced. In addition, if the gas to be treated contains VOCs that are easily condensed regardless of the water content, the concentrated and desorbed VOCs that are easily condensed on the regeneration outlet side may be condensed into a tar-like liquid. Conceivable.

If the casing on the regeneration outlet side is contaminated by the generation of tar-like liquid matter, and the honeycomb rotor and peripheral members are also contaminated by the liquid matter flowing out, it looks bad and it takes time and cost to clean the equipment. It also leads to corrosion of the equipment, and it is necessary to replace the honeycomb rotor and members. Further, when the tar-like liquid material flows into the honeycomb rotor, the performance is deteriorated and the pressure loss is increased. Further, if the accumulation of tar-like liquid matter progresses, it may lead to ignition and burning from the VOC concentrator.

The high boiling point VOC accumulated in the honeycomb rotor can be removed by the activation treatment in the high temperature regeneration mode described in Patent Document 1, but the normal operation mode of the VOC concentrator is the VOC treatment for adsorbing and removing VOCs from the gas to be treated. The mode. That is, even if the high boiling point VOCs accumulated in the high temperature regeneration mode are periodically separated from the honeycomb rotor, it is inevitable that the liquid matter will be generated on the regeneration outlet side if the conditions for generating the liquid matter are met. In addition, while the regeneration temperature in the VOC processing mode is around 200 ° C., in the high temperature regeneration mode, the regeneration is usually performed at about 300 ° C., so that the cost of heat-resistant seals, casings and other honeycomb rotor peripheral members that can withstand this high temperature is high. It gets higher.

In desiccant dehumidifiers and other gas treatment equipment, high-humidity moisture is condensed on the regeneration outlet side, and acid and alkaline components are dissolved in this condensed water, causing corrosion and honeycombs of the equipment, similar to VOC concentrators. Rotor performance degradation may occur.

In view of the above situation, the inventor analyzed the liquid matter generated on the regeneration outlet side in gas treatment equipment such as VOC concentrators and desiccant dehumidifiers, investigated the root cause of the liquid matter, and conducted a diligent study. rice field. As a result, it was found that if the generation of condensed water that causes the generation of liquid matter is suppressed, the generation of liquid matter is also eliminated, and the present invention has been reached. An object of the present invention is to provide a gas treatment apparatus capable of preventing the generation of a liquid substance on the regeneration outlet side by a simple method.

The gas treatment apparatus of the present invention includes a honeycomb rotor, the honeycomb rotor is divided into at least a treatment zone and a regeneration zone, a gas to be treated is passed through the treatment zone, and the gas that has passed through the treatment zone is sent to a supply destination or the atmosphere. A gas that is released, a part of the gas to be treated and / or the outside air is passed through the heating means, the gas that has passed through the heating means is passed through the regeneration zone, and the gas that has passed through the regeneration zone is released to the subsequent device or the atmosphere. In the processing apparatus, the temperature of the gas that has passed through the regeneration zone is 60 to 120 ° C.

Since the gas treatment apparatus of the present invention is configured as described above, it is possible to prevent the generation of liquid matter by a simple method and at no cost. As a result, the performance of the honeycomb rotor can be stably maintained for a long period of time, the frequency of replacing the members of the gas processing device and the honeycomb rotor is reduced, which leads to cost reduction.

FIG. 1 is an example of a VOC concentrated recovery flow. FIG. 2 is a diagram showing a tar-like liquid material generated in a VOC concentrator that was operated at a regeneration outlet temperature of 50 ° C. FIG. 3 is a diagram showing a state on the regeneration outlet side, which was operated at the regeneration outlet temperature of 100 ° C. by performing the same exhaust gas treatment at the same site as the VOC concentrator of FIG. 2 in another VOC concentrator. FIG. 4 is a graph comparing the VOC removal rates by performing a normal regeneration operation and a regeneration outlet temperature rise operation with four types of VOCs (xylene, ethylbenzene, toluene, butylbenzene) in a VOC concentrator.

FIG. 1 is an example of a VOC concentrated recovery flow. The honeycomb rotor 1 is divided into at least a processing zone 2 and a regeneration zone 3 by a separator 9. In the separator 9, the reproduction zone 3 is surrounded by a pair of V-shaped straight separators and arc-shaped separators (hereinafter referred to as "V zone"). In addition, the gas in each zone is covered with a casing (not shown) so that it can be sent through each air supply pipe. The honeycomb rotor 1 is made by molding inorganic fiber paper into a honeycomb shape and supporting an adsorbent such as hydrophobic zeolite. The honeycomb rotor 1 is rotated by a geared motor or the like (not shown) to generate a VOC. Can be continuously adsorbed and removed and concentrated and desorbed.

The VOCs in the gas to be processed that have passed through the prefilter 5 are adsorbed and removed when they pass through the processing zone 2 of the honeycomb rotor 1. The gas that has passed through the treatment zone is sent to the supply destination by the treatment fan 6 or is released to the atmosphere. When the honeycomb on which the VOC is adsorbed rotates and shifts to the regeneration zone 3, the adsorbed VOC is 5 to 15 with the regenerated gas heated by the heating means 7 having an air volume of 1/5 to 1/15 of the treated air volume at around 200 ° C. It is double-enriched and desorbed, and is sent to a subsequent device (not shown) such as a combustion processing device by the regeneration fan 8 or released to the atmosphere. The honeycomb that has passed through the regeneration zone 3 moves to the cooling zone 4, is cooled, and moves to the processing zone 2 again. A gas composed of a part of the gas to be treated, the outside air, and the gas that has passed through the treatment zone 2 is sent to the cooling zone 4. The gas that has passed through the cooling zone 4 is heated by the heating means 7 (regeneration heater or the like) and sent to the regeneration zone 3 as the regeneration gas.

Although the VOC concentrator is provided with the processing zone 2, the regeneration zone 3, and the cooling zone 4, it is possible to provide only the processing zone and the regeneration zone without providing the cooling zone, and to provide other zones. You may. Further, the gas sent to the regeneration zone 3 as the regeneration gas may be a part of the gas to be treated and / or the outside air.

Here, the processing inlet temperature is, for example, 20 to 30 ° C., and the regeneration outlet temperature is usually operated so as to be + 20 to 30 ° C. (generally 40 to 60 ° C.) with respect to the processing inlet temperature (hereinafter, "" "Normal regeneration operation"). However, at this regeneration outlet temperature, as described above, water may condense on the regeneration outlet side and a liquid substance may be generated. Therefore, in the present invention, in order to prevent the generation of liquid matter, the regeneration outlet temperature is further increased to 60 to 120 ° C., more preferably 70 to 120 ° C. (hereinafter, “regeneration outlet temperature increase operation””. That.). It should be noted that the operation is performed so as to be in this regeneration outlet temperature range (60 to 120 ° C.) regardless of conditions such as the regeneration inlet temperature, the air volume, and the components of the gas to be treated.

In Patent Document 1, in the "high temperature regeneration mode" operation, the regeneration outlet temperature is operated so as to be 50 to 150 ° C. lower than the regeneration inlet temperature, but in the present invention, the regeneration outlet temperature is increased in the normal VOC processing mode. It differs in that it operates like this. If a person skilled in the art operates the honeycomb rotor so that the regeneration outlet temperature is as high as 60 to 120 ° C., more preferably 70 to 120 ° C. as in the present invention, the performance of the honeycomb rotor deteriorates. It does not lead to the idea of operating in the range of +20 to 30 ° C. and intentionally raising the regeneration outlet temperature as in the present invention. There is also a method to raise the regeneration outlet temperature by adjusting the rotation speed, but if it deviates from the optimum rotation speed, which is the rotation speed with the highest removal performance, the performance of the honeycomb rotor will deteriorate, so it is purposely done. Those skilled in the art do not do anything that shifts.

As a result of the inventor's investigation and diligent study on the cause of the generation of tar-like liquid matter generated on the regeneration outlet side, the present invention causes condensation of water when the regeneration outlet temperature is as low as 40 to 60 ° C., which is tar. It is said that the generation of liquid matter will be reduced if the regeneration temperature is intentionally raised to 60 to 120 ° C, more preferably 70 to 120 ° C, which is a temperature range in which condensed water does not occur, after finding out that it causes the generation of liquid matter. Based on the proof, the invention was reached.

Absolute humidity in air at 100% RH relative humidity increases exponentially with increasing temperature. For example, at 40 ° C, it is 49 g / kg (DA), but at 60 ° C it is 152 g / kg (DA), which is about three times that of 40 ° C, and at 70 ° C, it is 277 g / kg (DA), which is about six times that of 40 ° C. Rise. In a gas treatment device that processes a large amount of air, a drift may occur in the part near the inner peripheral part of the honeycomb rotor in the V zone on the regeneration outlet side or in the outer peripheral wall part of the casing, or the temperature may be affected by the outside air conditions around the device. Is reduced, and liquid matter is easily generated and adhered. Therefore, in the regeneration outlet temperature raising operation of the present invention, the regeneration outlet temperature is raised to at least 60 ° C. or higher, more preferably 70 ° C. or higher. On the other hand, if the regeneration outlet temperature becomes too high, the performance of the honeycomb rotor deteriorates, so the temperature is limited to 120 ° C.

FIG. 2 is a tar-like liquid material generated in the casing on the regeneration outlet side of the VOC concentrator that was operated at the regeneration outlet temperature of 50 ° C. (normal regeneration operation). The part surrounded by the ellipse was the part where the gas having the highest regeneration outlet temperature was sprayed immediately before the transition from the regeneration zone to the cooling zone, so no tar-like liquid matter was attached. From this, it can be seen that the effect of preventing the generation of tar-like liquid matter can be seen by raising the regeneration outlet temperature.

On the other hand, FIG. 3 shows the regeneration outlet, which was operated at the regeneration outlet temperature of 100 ° C. (regeneration outlet temperature rise operation) by performing the same exhaust treatment at the same site as the VOC concentrator and another VOC concentrator shown in FIG. It is the state inside the casing on the side. It can be seen that no tar-like liquid matter was generated by raising the regeneration outlet temperature even though the same exhaust treatment was performed at the same site. It should be noted that what appears to be slightly attached to the casing in FIG. 3 is rust, dust, etc., and is not a tar-like liquid substance.

The following methods can be mentioned as a method for performing the regeneration outlet temperature raising operation of the present invention. The simplest method is to adjust the number of revolutions. When the rotation speed is lowered from the optimum rotation speed in the normal regeneration operation and the rotation speed is slowly rotated, the regeneration heat is transferred to the entire rotor and the regeneration outlet temperature rises.

Next, by bypassing a part of the regeneration inlet gas that has passed through the heating means 7 to the regeneration outlet side, the heating gas having a high temperature can be mixed with the regeneration outlet gas to raise the regeneration outlet temperature. Those skilled in the art cannot come up with such an idea because the concentration of the concentrated VOC is lowered, the removal performance is lowered, and the cost of bypassing is increased.

Furthermore, by burying a heating device such as a plate-shaped heater on the wall surface of the V zone (including the casing) that divides the regeneration outlet side, the regeneration outlet gas can be indirectly heated and the regeneration outlet temperature can be raised. can. Those skilled in the art cannot come up with the idea of installing a costly plate-shaped heater or the like to raise the regeneration outlet temperature, which deteriorates the performance. Alternatively, the regenerated outlet gas may be used for heat exchange using the exhaust gas after combustion as a heat source.

In any case, as described above, raising the regeneration outlet temperature means that the honeycomb cooling effect in the cooling zone is reduced and the performance of the honeycomb rotor is lowered. Do not drive.

FIG. 4 is a graph comparing the VOC removal rates by performing a normal regeneration operation and a regeneration outlet temperature rise operation with four types of VOCs (xylene, ethylbenzene, toluene, butylbenzene) in a VOC concentrator. The horizontal axis is the processing inlet VOC concentration, and the vertical axis is the VOC removal rate. Compared with the normal regeneration operation, in the regeneration outlet temperature rise operation, the removal rate was reduced by 0.5 to 1 point as a whole. Normally, VOCs with a high boiling point contained in tar-like liquids often contain VOCs having a larger polarity and molecular structure than these four types of VOCs, so the actual decrease in performance depends on these four types of VOCs. It is expected to be small in comparison.

Here, if the regeneration outlet temperature rise operation is performed so that the regeneration outlet temperature becomes 120 ° C., the VOC removal rate decreases by 2 to 5 points depending on the type of VOC, so that the upper limit of the regeneration outlet temperature rise operation is performed. Is 120 ° C. Further, if the regeneration outlet temperature is too high, the heat resistant temperature of the regeneration fan 8 may be exceeded, so it is desirable to set the upper limit to 120 ° C.

If the regeneration outlet temperature is raised, the performance will be slightly reduced, but the performance will not be significantly impaired. In the long term, in the case of a VOC concentrator, VOCs having a high boiling point accumulate in the honeycomb rotor, and the performance gradually deteriorates. In addition to this, in normal regeneration operation, tar-like liquid matter is generated, the equipment and honeycomb rotor are contaminated, the performance deteriorates, and the cost of corrosion, cleaning and replacement of the equipment increases, and ignition and burning occur. There is also a risk of. On the other hand, by performing the regeneration outlet temperature rise operation, the initial performance is slightly deteriorated, but tar-like liquid matter is not generated, the frequency of cleaning and replacement is reduced, and the cost is lower than that of the normal regeneration operation. Become. Therefore, in the long term, the operation of increasing the temperature of the regeneration outlet can maintain the performance more stably, and has a cost merit.

In particular, in the method of raising the regeneration outlet temperature by adjusting the rotation speed, it is not necessary to install a new device, and the adjustment can be easily performed only with the existing device. The other methods do not result in a significant cost increase. The above-mentioned method of raising the regeneration outlet temperature (adjustment of the rotation speed, bypass of the heating gas, burying of the heating device on the regeneration outlet side) may be used alone or in combination.

In case liquid matter is generated during normal regeneration operation, preventive measures (weirs, etc.) are provided to prevent the liquid matter from flowing out into the honeycomb rotor, drainage is provided on the regeneration outlet side, and the honeycomb rotor is stored. The casing may be inclined so that the regeneration inlet side is higher than the regeneration outlet side. Further, a treatment for lowering the humidity may be performed, such as dehumidifying the treatment target gas and / or the reclaimed gas so that the regeneration outlet gas does not become high humidity.

According to the gas treatment apparatus of the present invention, the generation of liquid matter at the regeneration outlet can be prevented by a simple method, so that the regeneration outlet gas is condensed and the generation of liquid matter is generated regardless of the type of gas such as VOC and dehumidification. It can be applied to all properties that may be affected.

1 Honeycomb rotor 2 Processing zone 3 Regeneration zone 4 Cooling zone 5 Pre-filter 6 Processing fan 7 Heating means 8 Regeneration fan 9 Separator

Claims (7)

A honeycomb rotor is provided, and the honeycomb rotor is divided into at least a treatment zone and a regeneration zone, a gas to be treated is passed through the treatment zone, and the gas passing through the treatment zone is sent to a supply destination or released to the atmosphere to be treated. A part of the gas and / or the outside air is passed through the heating means, the gas that has passed through the heating means is passed through the regeneration zone, and the gas that has passed through the regeneration zone is released to the subsequent device or the atmosphere. A VOC concentrator , wherein the temperature of the gas that has passed through the regeneration zone is 60 to 120 ° C. The VOC concentrator according to claim 1, wherein a cooling zone is further provided between the processing zone and the regeneration zone. A gas consisting of a part of the gas to be treated, the outside air, and at least one of the gases that have passed through the treatment zone is passed through the cooling zone, and the gas that has passed through the cooling zone is passed through the heating means. The VOC concentrator according to claim 1 or 2, wherein the VOC concentrator is characterized. The VOC concentrator according to any one of claims 1 to 3, wherein the temperature of the gas passing through the regeneration zone is adjusted by adjusting the rotation speed of the honeycomb rotor. .. The first aspect of the present invention is characterized in that the temperature of the gas that has passed through the regeneration zone is adjusted by bypassing a part of the gas that has passed through the heating means and passing the gas through the outlet side of the regeneration zone. Item 6. The VOC concentrator according to any one of Item 4. Any of claims 1 to 5, wherein a heating device is embedded in the V zone that partitions the outlet side of the regeneration zone to adjust the temperature of the gas that has passed through the regeneration zone. The VOC concentrator according to one item. The VOC concentrator according to any one of claims 1 to 6, wherein a preventive means for preventing the liquid material generated on the outlet side of the regeneration zone from flowing out to the honeycomb rotor is provided.

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