JPH0685851B2 - Component adsorbent in gas - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a separation / purification / recovery of a solvent recovery device for recovering a solvent from a processing gas containing a solvent such as CFC or a dehumidifier for removing water from the air. The present invention relates to a component adsorbent in a gas which is used in an apparatus and which adsorbs a specific component in a processing gas at a low temperature and desorbs an adsorbed component at a high temperature.

[Prior Art] Recently, concern over environmental pollution has increased, and regulations have been tightened from the viewpoint of environmental protection, and the emission of carbon waste into the atmosphere tends to be prohibited. In particular, air pollution caused by Freon gas containing chlorine is attracting attention as a serious problem on a global scale, and therefore emission restrictions on Freon gas are about to be imposed. Although this CFC emission regulation calls for the complete discontinuation of CFC gas in the future, during the present period until the replacement of CFC gas was developed, CFC gas that had been conventionally emitted to the atmosphere was excluded from the system. The next best thing is to collect and reuse it so that it is not discharged to. Therefore, various solvent recovery devices have been developed.

In a conventional batch-type solvent recovery apparatus, for example, in a plurality of adsorption towers storing an adsorbent made of activated carbon formed into pellets, the solvent-containing gas is selectively and alternately passed through the adsorption tower. The adsorbent adsorbs the solvent to obtain a clean gas. Then, high-temperature steam is caused to flow through the adsorbent in the adsorption tower after adsorbing the solvent, and the adsorbent is heated by the steam to desorb the solvent from the adsorbent and regenerate the adsorbent. By alternately repeating adsorption and desorption in a plurality of adsorption towers in this way, the solvent is removed from the solvent-containing air to obtain clean air. If necessary, a cooling gas at a low temperature such as room temperature is passed through the adsorption tower that has completed the desorption process to cool the adsorbent to improve its adsorption efficiency and then move to the adsorption process. There is.

However, such a conventional solvent recovery apparatus has a drawback that it is difficult to avoid decomposition of the solvent, that is, generation of acid, because steam is used to regenerate the adsorbent. That is, when a solvent such as Freon is adsorbed by activated carbon under a condition of being exposed to water vapor for a long time, a part of the solvent is decomposed to generate hydrochloric acid and hydrofluoric acid. Then, problems such as deterioration of solvent purity in the recovered solvent and mixing of acid in waste water and purified gas occur. Also, when recovering an azeotropic mixed solvent containing alcohol, alcohol dissolves in water and most of the part is discharged together with the discharged wastewater, so it is necessary to take measures against BOD and COD in the wastewater. There are also some problems.

Therefore, it has been attempted to regenerate the adsorbent by electric heating. In this case, a coil-shaped electric heater is arranged around the adsorbent, the heater is connected to an appropriate power source to generate resistance heat, and this heat heats the adsorbent to desorb the solvent from the adsorbent. However, this heating method has a drawback that the heating efficiency of the adsorbent is low because the adsorbent is heated from the surroundings.

Therefore, the inventors of the present application have proposed a solvent recovery device that does not use steam for regenerating the adsorbent and has high heating efficiency (Japanese Patent Application No. 1-144987). This solvent recovery device is one in which the adsorbent is heated by a sheet heater, and an example thereof is shown in FIG. That is, the two adsorption towers 1 and 2 are configured by accommodating the adsorbent 40 in a rectangular tubular housing 51 as shown in FIGS. 4 to 6. And this adsorbent
In the vicinity of both ends of 40, a laminated body having a structure in which a sheet 55 of fiber activated carbon is sandwiched by a pair of punching plates 54 each having punched holes is arranged slightly apart from each end of the adsorbent 40. I am doing it. This laminated body is a rectifying member that rectifies the air introduced into the adsorption tower 1 (2) and causes the air to flow through the adsorbent 40 with a uniform flow rate distribution. Further, lids 52 and 53 having a gas inlet or a gas outlet are attached to both ends of the housing 51, respectively.

The adsorbent 40 includes a seat heater 42 between a plurality of activated carbon adsorbents 41.
It is arranged by interposing. Then, the sheet heater 42 is energized to generate resistance heat, thereby heating the adsorbent 41 in contact with the sheet heater 42. By stopping the power supply to the seat heater 42, the adsorbent 41 is allowed to cool.

Air containing a solvent such as CFC is supplied to the treatment blower 3 through a pipe 21. The processing blower 3 is connected to the cooler 4 via the pipe 22, and the cooler 4 is connected to the pipe 23.
And the pipes 23a and 23b branched from the pipe 23 are connected to the first and second adsorption towers 1 and 2, respectively. The solvent-containing air is selectively sent to the first and second adsorption towers 1 and 2 by the processing blower 3 via the pipes 22, 23, 23a and 23b. Cooling water is supplied to the cooler 4, whereby the solvent-containing air sent into the adsorption towers 1 and 2 is cooled in advance. On-off valves V ₁ and V ₃ are provided in the pipes 23a and 23b, respectively.

The purified air discharged from the first and second adsorption towers 1 and 2 is discharged into the atmosphere through the pipes 24a and 24b and the main pipe 24 to which these pipes 24a and 24b are connected. On-off valves V ₂ and V ₄ are provided in the pipes 24a and 24b, respectively.

The pipe 24 is connected to one end of each of the first and second adsorption towers 1 and 2 via pipes 26a and 27a and pipes 26b and 27b, respectively. Atmosphere opening valves V ₆ and V ₈ are provided in the pipes 26a and 26b, respectively, and carrier air flow rate adjusting valves V ₁₀ and V ₁₂ are provided in the pipes 27a and 27b, respectively. And the first and second
Pipes 25a and 25b and pipes at the other ends of the adsorption towers 1 and 2, respectively.
28a and 28b are connected. The pipes 25a and 25b join the pipe 25, and the pipe 25 is connected to the pipe 22. The pipe 25 is provided with a cooling blower 5 for sucking the air in the adsorption towers 1 and 2 via the pipes 25a and 25b.
On-off valves V ₅ and V ₇ are provided in 25b, respectively.

Further, the pipes 28a and 28b join the pipe 28 and are connected to the separator 8 via the pipe 28. Further, the vacuum pump 6 and the cooler 7 are interposed in the pipe 28.
Air in the adsorption towers 1, 2 is sucked by the vacuum pump 6 via a, 28b, 28, and the sucked air is cooled by the cooler 7 and then fed to the separator 8. Chill cooling water is supplied to the cooler 7, and the solvent-containing air in the adsorption towers 1 and 2 sucked by the vacuum pump 6 is cooled by the chill cooling water to condense the solvent and water in the solvent-containing air. The condensed solvent liquid and water are supplied to the separator 8 together with the air containing the uncondensed solvent.

In the separator 8, the water and the solvent liquid are separated, and the solvent liquid is collected and collected in the tank 9. Water is discharged from the separator 8. On the other hand, the air containing the uncondensed solvent is
It is returned to the pipe 21 through the pipe 29 and is again subjected to the adsorption and desorption process together with the process air.

Next, the operation of the solvent recovery device configured as described above will be described.

First, the adsorbent housed in the first adsorption tower 1 is in a regenerated state and in an active state, and the adsorbent housed in the second adsorption tower 2 is in an adsorbed state, and the solvent is sufficiently adsorbed. Suppose that you are in a state of doing. Therefore, the first adsorption tower 1 carries out the adsorption step and the second adsorption tower 2 carries out the desorption step.
In this case, the open / close valves V ₁ and V ₂ are opened, and the open / close valves V ₅ , V ₆ and V ₉ are closed. The flow rate adjusting valves V ₁₀ and V ₁₂ are set so that a predetermined regeneration gas flows when the pressure inside the adsorption tower is reduced. Also, open / close valves V ₃ , V ₄ , V ₇ , V ₈ are closed, open / close valve V ₁₁ is opened, and flow rate adjustment valve V
₁₂ is set to a predetermined opening degree, and the regeneration gas having a predetermined flow rate is allowed to flow through the flow rate adjusting valve V ₁₂ . Further, the processing blower 3 is constantly driven, and the vacuum pump 6 and the cooling / cleaning blower 5 are selectively driven. At the beginning of this process, the vacuum pump 6 is in the operating state and the cooling and cleaning blower 5 is in the inactive state.

Then, the solvent-containing air is sucked by the blower 3 via the pipe 21, is supplied to the cooler 4 via the pipe 22, and is cooled. As a result, the solvent-containing air is cooled to a low temperature where the adsorption efficiency of the adsorbent is high, and then the pipe 2
It is sent to the first adsorption tower 1 through 3,23a. The adsorbent 40 is housed in the adsorption tower 1, and the solvent-containing air flows through the adsorbent 41 of the adsorbent 40, and the contained solvent is adsorbed by the adsorbent 41. The clean air from which the solvent has been removed and purified is discharged to the atmosphere via the pipes 24a and 24.

On the other hand, in the second adsorption tower 2, the inside of the adsorption tower 2 is sucked by the vacuum pump 6 through the pipes 28 and 28b, and the purified air flowing through the pipe 24 passes through the flow rate adjusting valve V ₁₂ to a predetermined level. Introduced at a flow rate. Then, in the adsorbent 40 in the adsorption tower 2, the seat heater 42 is energized to cause the seat heater 42 to generate resistance heat, and the adsorbent 41 in contact with the seat heater 42 is heated. As a result, the solvent adsorbed on the adsorbent 41 is desorbed, and the solvent desorbed from the adsorbent 41 is used as a carrier gas using the purified air introduced into the adsorption tower 2 via the flow rate adjusting valve V ₁₂ as a vacuum pump. It is sucked by 6 and supplied to the cooler 7. The exhaust air of the adsorption tower 2 in which the solvent is concentrated is cooled by chilled water in the cooler 7,
The solvent and water in the exhaust air are condensed to be solvent liquid and water, which are supplied to the separator 8. The air containing the uncondensed solvent is returned from the separator 8 to the pipe 21 via the pipe 29, and together with the solvent-containing air sent via the pipe 21, the adsorption step is performed by the treatment blower 3. It is introduced into the adsorption tower 1. Therefore, the air containing the uncondensed solvent after the solvent and the water are condensed from the solvent concentrated air in the cooler 8 is supplied to the first adsorption tower 1 to adsorb and remove the uncondensed solvent. In the separator 8, the solvent liquid and the water are separated by specific gravity, the water is discharged, and the solvent liquid is collected in the tank 9.

Then, after the solvent is sufficiently desorbed from the adsorbent in the second adsorption tower 2, the second adsorption tower 2 is cooled from the desorption step to the cooling step while the first adsorption tower 1 is still performing the adsorption step. Move to. In other words, the valve _{V 1, V 2, V 5} , V 6, V 9 and valve V _3, V ₄ is intact, the on-off valve V ₈ opens, the opening and closing valve V ₁₁ is closed. By doing so, in the adsorption tower 2 which has been depressurized until then,
Air is supplied through the pipe 26b and becomes normal pressure. Then, the opening and closing valve V ₈ opens another off valves as is, on-off valve V _4, V
₇ is closed. Also, the vacuum pump 6 stops its operation,
The cooling wash blower 5 starts operation. Then, in the second adsorption tower 2, the purified air flowing through the pipe 24 is sucked by the cooling / cleaning blower 5 and introduced through the pipe 24b. This purified air is used as a cooling gas in the second adsorption tower 2
After cooling the adsorbent therein, the adsorbent is returned to the pipe 22 through the pipes 25b and 25, and is supplied to the first adsorption tower 1 together with the solvent-containing air. As a result, the solvent mixed in the cooling gas when flowing through the second adsorption tower 2 is adsorbed by the adsorbent in the first adsorption tower 1 and removed.

After that, the first adsorption tower 1 is switched to the desorption step and the adsorption step of the second adsorption tower 2, and thereafter such an operation is alternately repeated to recover the solvent from the solvent-containing air.

In this way, the adsorbent can be regenerated with relatively high efficiency without using water vapor which may generate acid.

Thus, the adsorbent 40 using such a solvent recovery device
Is a honeycomb adsorbent 41 having an uneven surface and a sheet heater
In order to prevent the processing gas from passing through the space 42, the honeycomb adsorbent 41 and the sheet heater 42 are usually bonded and fixed by an adhesive. Further, since the seat heater 42 is processed inside the insulating flat plate, a metal thin plate may be further bonded to the surface thereof in order to enhance the heat dispersibility thereof.

[Problems to be Solved by the Invention] However, in the adsorbent used in the above-mentioned solvent recovery device, etc., in principle, the heating efficiency is improved as compared with that in which an electric heater is arranged around the adsorbent. Though
It cannot be said that a sufficiently high heating efficiency is obtained.

That is, the adsorbent 41 and the seat heater 42 are fixed with an adhesive in order to fill the gap between them, but the resin forming this adhesive has poor thermal conductivity. Therefore, the heat of the seat heater 42 is not quickly transferred to the adsorbent 41.

Further, since the honeycomb activated carbon is not easy to form as compared with metal, the forming accuracy of the adsorbent 41 is not sufficient, and therefore,
It is extremely difficult to dispose the sheet heater 42 between a large number of adsorbents 41 so that no gap is formed between the adsorbents 41. For this reason, a large amount of adhesive having poor thermal conductivity is used, and the number of man-hours for assembling the adsorbent increases.

Furthermore, since the housing 51 made of stainless steel is also heated by heating the adsorbent 41, energy loss is large and it takes time to raise the temperature of the adsorbent 41.

The present invention has been made in view of such problems,
It is possible to improve the thermal conductivity from the seat heater to the adsorbent, and to shield the process gas from flowing between the seat heater and the adsorbent, despite the dimensional tolerance of the honeycomb formed body. It is an object of the present invention to provide a component adsorbent in a gas, which has a higher heating efficiency than that of the conventional one, and is low in cost and highly practical.

[Means for Solving the Problems] A component adsorbent in gas according to the present invention includes a plurality of honeycomb adsorbents, a storage case made of Bakelite for storing the plurality of honeycomb adsorbents, and the honeycomb adsorbent. A sheet heater disposed between the sheet heater and the honeycomb adsorbent, and a heat transfer buffer having a higher thermal conductivity than the honeycomb adsorbent interposed between the sheet heater and the honeycomb adsorbent.

[Operation] In the present invention, a plurality of honeycomb adsorbents are arranged between the sheet heater and the honeycomb adsorbent with a buffer material having high thermal conductivity interposed. Since this cushioning material has higher thermal conductivity than the honeycomb adsorbent, heat generated from the seat heater is quickly transferred to the honeycomb adsorbent. That is, since the heat transfer in the buffer material is faster than that in the honeycomb adsorbent material, the heat generated in the sheet heater does not stay in the buffer material, and the heat transfer is rate-controlled inside the honeycomb adsorbent material. Therefore, it is possible to quickly raise the temperature of the adsorbent.

The adsorbent is stored in a Bakelite storage case. Therefore, due to the heat insulating effect of the bakelite, the heat generated from the seat heater is suppressed from being transmitted to the housing, and the temperature rising rate of the adsorbent is further improved.

Further, since this cushioning material has flexibility and is interposed between the seat heater and the adsorbent by being deformed in accordance with the shape of the gap between them, the cushioning material is interposed between the seat heater and the adsorbent. Has virtually no gap. Therefore, it is possible to prevent the processing gas from flowing through the inside of the adsorption tower without passing through the adsorbent. When a felt-like sheet made of carbon fiber is used as the cushioning material, the above-mentioned effect can be reliably obtained because the pressure loss when ventilating the inside of the felt-like sheet is high.

Furthermore, since this cushioning material is interposed, the dimensional tolerance that occurs when the honeycomb adsorbent is molded is absorbed by the deformation of the cushioning material. Therefore, the work of arranging the plurality of honeycomb adsorbents in the housing of the adsorption tower is facilitated, and the work man-hour and the processing cost can be reduced.

Next, the reasons for limiting the material of the storage case will be described.

In the present invention, it is necessary to press the honeycomb adsorbent with an appropriate pressure in order to improve the heat conduction efficiency by bringing the honeycomb adsorbent into close contact with the cushioning material. Therefore, it is necessary that the material of the storage case has such strength that it is not deformed by this appropriate pressure. Further, since the storage case is exposed to a solvent such as CFC and an acid such as hydrochloric acid or hydrofluoric acid generated by slightly decomposing these, the storage case has good solvent resistance and acid resistance. It is necessary. Further, since the adsorbent is exposed to a temperature of 150 ° C. or higher when it is regenerated, it is necessary to have heat resistance at a temperature that is equal to or higher than the temperature of this regeneration. Furthermore, since the storage case is required to have heat insulating properties, it is necessary that the material of the storage case has a large thermal resistance. Furthermore, the sheet heater is insulated, but since the felt-like sheet made of the honeycomb adsorbent and the carbon fiber is a conductor, there is a risk of electric leakage when the insulation of the heater is broken. Therefore, it is preferable that the material of the storage case has high electrical insulation.

By the way, general plastic materials have good strength, heat resistance, and electric insulation, but have insufficient solvent resistance and heat resistance. Further, a general rubber-based material has good heat resistance, heat resistance and electric insulation, but has a drawback that the strength, heat resistance and solvent resistance are not sufficient. Further, although Teflon satisfies these conditions, it has the drawback of high material cost. on the other hand,
Bakelite (phenolic resin) satisfies the above-mentioned conditions and has a low material cost. Therefore, the material of the storage case is bakelite.

[Embodiment] Next, an embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a plan view showing an adsorbent according to an embodiment of the present invention, and FIG. 2 is an enlarged perspective view showing a part thereof.

The adsorbent 30 includes a plurality of adsorbents 31, a storage case 35 that accommodates the adsorbents 31, and the like. Storage case 35
The inside is divided into three chambers by two partition plates, and a plurality of adsorbents 31 are arranged and loaded in each chamber. Also, this adsorbent 31 is a storage case.
Within 35, for example, three layers are vertically stacked.

The adsorbent 31 is mainly composed of activated carbon and is formed into a honeycomb shape. Then, in each row, the adsorbents that are adjacent
A laminated body of a seat heater 32 and a felt-like sheet 33 as a cushioning material is interposed between the 31. This laminated body has a structure in which the sheet heater 32 is sandwiched by a pair of felt-like sheets 38. Therefore, the felt-like sheet 33 is interposed between the seat heater 32 and the honeycomb adsorbent 31.

The seat heater 32 is formed, for example, by printing a resistor on an insulating substrate and coating the resistor with silicon rubber or the like to electrically insulate the resistor. A lead wire 34 for connecting to an appropriate power source is connected to the seat heater 32. On the other hand, the felt-like sheet 33 is made of a material having higher thermal conductivity than the sheet heater 32. As the felt-like sheet 33, there is a felt-like sheet of activated carbon fiber.

The storage case 35 is assembled by four side plates and two partition plates made of Bakelite. Then, the plurality of adsorbents 31 are sandwiched from both sides in the thickness direction and assembled by pressing with an appropriate pressure. As a result, the adsorbent 31 sheet heater 32 and felt-like sheet 33
Are in close contact with each other. The storage case 35 may be assembled by joining the side plate and the partition plate with, for example, an L-shaped metal fitting, or may be assembled by directly screwing the side plate and the partition plate together. Also, the inner surface of the housing and the storage case
Silicon caulking material is filled between 35 and
All the processing gas passes through the inside of the adsorbent 30.

In the adsorbent 30 configured as described above, the processing gas such as the solvent-containing air flows through the adsorbent 30 in the longitudinal direction thereof. As a result, the adsorbent 31 adsorbs a component such as CFC that should be removed from the treated air. On the other hand, by energizing the seat heater 32, the seat heater 32 generates resistance heat. When the adsorbent 31 is heated by the heat generated by the seat heater 32, the adsorbent 31 desorbs the solvent that has been adsorbed up to that point. In this case, since the felt-like sheet 33 is formed of a material having a higher thermal conductivity than the adsorbent 31, the heat from the seat heater 32 does not stay in the felt-like sheet 33 and is absorbed in the adsorbent 31. Promptly transmitted. Also, the adsorbent 31
Since the movement of the heat transferred to the storage case 35 is suppressed by the storage case 35, the heat is retained in the adsorbent 31 to raise the temperature of the adsorbent 31. Therefore, the adsorbent 31 heats up with an excellent rising property when the sheet heater 32 is energized. Further, since the felt-like sheet 33 made of activated carbon fiber has flexibility and is easily deformed, it is interposed between the adsorbent 31 and the seat heater 32 so as to be in close contact with both. Therefore, it is possible to avoid a situation in which the processing air does not pass through the adsorbent 31 and flows through the space between the adsorbent 31 and the seat heater 32. Furthermore, since the felt-like sheet 33 has flexibility as described above, even if the adsorbent 31 has a molding dimension tolerance, it is absorbed and the adsorbent 31 is easily sealed in the storage case 35. Can be placed at.

[Effects of the Invention] According to the present invention as described above, since a cushioning material having a high pressure loss such as a felt-like sheet is arranged between the seat heater and the adsorbent, the space between the seat heater and the adsorbent is increased. It is possible to prevent the processing gas from flowing through the gap, and it is possible to remove the removal components in the processing gas with extremely high efficiency. Also, since this buffer material has higher thermal conductivity than the adsorbent material, unlike the conventional case where the seat heater and the adsorbent material are bonded with an adhesive as in the past, the heat of the seat heater is quickly transferred to the adsorbent material. Therefore, the temperature of the adsorbent can be raised rapidly. Furthermore, since these adsorbents, seat heaters and cushioning materials are stored in a Bakelite storage case,
It is possible to prevent the heat from the heater from being absorbed by the housing of the adsorption tower. Therefore, the efficiency of the adsorption and desorption process in the solvent recovery device, the dehumidification device, or the like can be improved. Furthermore, since the dimensional tolerance of the adsorbent can be absorbed by the deformation of the cushioning material, the adsorbent can be easily assembled.

[Brief description of drawings]

FIG. 1 is a plan view showing an adsorbent according to an embodiment of the present invention, FIG. 2 is an enlarged perspective view of a part thereof, and FIG. 3 is a block diagram showing a solvent recovery device that does not use vapor for desorption. Fig. 4 is a longitudinal sectional view showing a conventional adsorption tower, Fig. 5 is a perspective view showing a conventional adsorbent housed in the adsorption tower, and Fig. 6 is a gas rectifier installed in the adsorption tower. It is a perspective view which shows a member. 1, 2; adsorption tower, 3; processing blower, 4, 7; cooler, 5; cooling blower, 6; vacuum pump, 8; separator, 9; tank, 21, 22, 23, 24,
25,28,29; Piping, 30,40; Adsorbent, 31,41; Adsorbent, 32,42;
Seat heater, 33,55; seat, 34; lead wire, 35; storage case, 51; housing, 52,53; lid, 54; punching plate

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location B01D 53/34 117 B

Claims (3)

[Claims] 1. A plurality of honeycomb adsorbents, a storage case made of bakelite for accommodating the plurality of honeycomb adsorbents, a seat heater arranged between the honeycomb adsorbents, the seat heater and the seat heater. A component adsorbent in a gas, comprising: a heat transfer buffer that is interposed between the honeycomb adsorbent and has a higher thermal conductivity than the honeycomb adsorbent. 2. The component adsorbent in a gas according to claim 1, wherein the heat transfer buffer is a felt-like sheet made of carbon fiber. 3. The adsorbent for a component in a gas according to claim 1, wherein the honeycomb adsorbent is made of activated carbon having a solvent adsorbing and desorbing action.