WO2015033455A1

WO2015033455A1 - Adsorbent-regenerating device

Info

Publication number: WO2015033455A1
Application number: PCT/JP2013/074177
Authority: WO
Inventors: 佐野　理志; 禎夫関谷
Original assignee: 株式会社日立製作所
Priority date: 2013-09-09
Filing date: 2013-09-09
Publication date: 2015-03-12
Also published as: JP6232435B2; JPWO2015033455A1

Abstract

The present invention addresses the problem of providing a device for regenerating adsorbent in which organic substances have been used, the device being capable of reducing the input energy for regenerating the adsorbent and also capable of reducing the amount of organic solvent used for cleaning that remains in the adsorbent when regenerated. To solve said problem, the present invention is characterized in that: the device for regenerating used adsorbents, which have been used for water treatment, by removing adsorbates therefrom uses a liquefied substance (A), which is in a liquid state as a result of maintaining the gaseous substance (A) at a saturated vapor pressure at normal temperature and normal pressure; the adsorbate is desorbed and eluted in the liquefied substance (A) by bringing the adsorbent and the liquefied substance (A) into contact in a treatment tank; the liquefied substance (A), which has been in contact with the adsorbent, is gasified in a vaporizer to separate the adsorbate; the gasified substance (A) is compressed in a compressor; and the compressed substance (A) is liquefied in a condenser.

Description

Adsorbent regenerator

The present invention relates to an apparatus for desorbing adsorbate from a used adsorbent and regenerating the adsorbent.

[Patent Document 1] and [Patent Document 2] exist as background arts in this technical field.

[Patent Document 1] discloses an apparatus for washing activated carbon used for water treatment with an organic solvent, and then desorbing the organic solvent and moisture from the activated carbon by heating steam.

[Patent Document 2] describes a device that regenerates a used adsorbent using a liquid organic solvent at room temperature and normal pressure, and increases the purity of the organic solvent used for washing by distillation and reuses it again. It is disclosed.

JP 07-313874 A JP-A 63-077751

As a method of regenerating used adsorbent such as activated carbon used for water treatment, there is a method of desorbing adsorbate from the adsorbent by washing using a liquid organic solvent.

In [Patent Document 1], in order to remove a large amount of organic solvent adhering during the regeneration of the adsorbent from the adsorbent, the adsorbent is separated by vaporizing water or the organic solvent using superheated steam. Therefore, enormous energy for producing superheated steam is indispensable, which increases the cost of adsorbent regeneration.

In [Patent Document 2], the organic solvent used during regeneration of the adsorbent remains attached to the adsorbent, and when the regenerated adsorbent is used for water treatment, the organic solvent may be mixed with the treated water. In addition, the organic solvent used for regeneration is separated from the adsorbate by distillation to increase its purity. However, in order to vaporize the organic solvent, it is necessary to input sensible heat and latent heat energy. In addition, since energy is consumed for heating and vaporizing moisture, a huge amount of energy is indispensable. In this case, part of the heating energy of the organic solvent can be covered by the heat of condensation of the organic solvent by heat exchange, but a large heat exchanger is required because of the enormous amount of energy transferred.

Therefore, the present invention provides an adsorbent regenerator that is as small as possible, can reduce the energy input during regeneration of the adsorbent, and can further reduce the amount of cleaning organic solvent remaining in the adsorbent during regeneration.

In order to achieve the above-mentioned problems, the present invention provides an adsorbent regenerator that removes adsorbate from a used adsorbent used in water treatment and regenerates it.
By using the liquefied substance A in a liquid state by holding the gaseous substance A at normal temperature and normal pressure under saturated vapor pressure, the adsorbate is desorbed by bringing the adsorbent and the liquefied substance A into contact with each other to form the liquefied substance A. A treatment tank for elution, an evaporator for separating the adsorbate by vaporizing the liquefied substance A in contact with the adsorbent, a condenser for liquefying the vaporized substance A, and sending the liquefied substance A And a pump.

In order to achieve the above-mentioned problem, the present invention provides an adsorbent regenerator that removes adsorbate from a used adsorbent used in water treatment and regenerates it.
By using the liquefied substance A in a liquid state by holding the gaseous substance A at normal temperature and normal pressure under saturated vapor pressure, the adsorbate is desorbed by bringing the adsorbent and the liquefied substance A into contact with each other to form the liquefied substance A. A treatment tank for elution, an evaporator for separating the adsorbate by vaporizing the liquefied substance A in contact with the adsorbent, a compressor for compressing the vaporized substance A, and the compressed substance A is liquefied. And a condenser.

Furthermore, the present invention provides an adsorbent regeneration apparatus,
In order to transfer heat between the material A on the upstream side and the material A on the downstream side of the compressor, a heat exchanger is installed.

Furthermore, the present invention provides an adsorbent regeneration apparatus,
The high temperature side of the evaporator and the low temperature side of the condenser are connected by a refrigeration cycle using a refrigerant.

Furthermore, the present invention provides an adsorbent regeneration apparatus,
Compressed air is injected from the lower part inside the treatment tank.

Furthermore, the present invention provides an adsorbent regeneration apparatus,
The adsorbent is controlled to float and become a fluidized bed by the flow of the substance A in the treatment tank.

Furthermore, the present invention provides an adsorbent regeneration apparatus,
A heater is installed in the lower part of the treatment tank, and the substance A under saturated vapor pressure is boiled.

Furthermore, the present invention provides an adsorbent regeneration apparatus,
The heater is installed such that a vertical sectional area is larger than a horizontal sectional area.

Furthermore, the present invention provides an adsorbent regeneration apparatus,
The adsorbent is put in a net-like container or bag so that the position of the adsorbent particles is not moved by the fluid force of the substance A.

Furthermore, the present invention provides an adsorbent regeneration apparatus,
The substance A is dimethyl ether.

Furthermore, the present invention provides an adsorbent regeneration apparatus,
The adsorbent is activated carbon or a derivative thereof.

According to the present invention, in the apparatus for regenerating the adsorbent, the gaseous organic substance is used at room temperature and normal pressure under the saturated vapor pressure, so that the adsorbent can be regenerated with a small input energy. Since it can be easily removed by vaporization under reduced pressure, it is possible to reduce the outflow of cleaning liquid to the treated water when using a regenerated adsorbent.

It is an example of the block diagram of the adsorbent reproduction | regeneration apparatus of this invention. It is another example of the block diagram of the adsorbent reproduction | regeneration apparatus of this invention. It is another example of the block diagram of the adsorbent reproduction | regeneration apparatus of this invention. It is an example of the internal structure of the processing tank which comprises the adsorbent reproduction | regeneration apparatus of this invention. It is another example of the internal structure of the processing tank which comprises the adsorbent reproduction | regeneration apparatus of this invention. It is further another example of the internal structure of the processing tank which comprises the adsorbent reproduction | regeneration apparatus of this invention. It is the reproduction | regeneration data of activated carbon using the adsorption agent reproduction | regeneration apparatus of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of the device of the present invention.
First, in the normal sewage treatment mode, the

valves

11, 12, and 15 are closed, and the

valves

13 and 14 are opened. By bringing the sewage into contact with the adsorbent filled in the treatment tank 2, impurities are adsorbed by the adsorbent, and purified water containing no impurities is obtained from the outlet of the treatment tank. If operation is continued in this state, adsorption saturation is reached and impurities leak out. Therefore, operation is temporarily stopped before the impurities leak and the adsorbent regeneration mode is entered. Water is removed from the treatment tank during the transition, but water and impurities remain attached to the adsorbent.

In the adsorbent regeneration mode, the

valves

11 and 12 are opened and the

valves

13 and 14 are closed. For regeneration of the adsorbent, substance A, which is a gas at normal temperature and pressure, is used. The substance A is held at a saturated vapor pressure in the circulation path of the regeneration mode, and a part thereof exists in a liquefied state. The figure also shows changes in temperature and pressure. Although this shows a different value depending on the substance A used, it is an example described for explaining the flow of energy.

First, the liquefied substance A is extracted from the lower part of the condenser 9 and sent to the treatment tank 2 through the valve 11 by the pump 1. In the treatment tank 2, the adsorbent is immersed in the liquefied substance A that has been fed. At this time, the impurities adsorbed on the adsorbent are desorbed due to their high affinity with the liquefied substance A, and are dissolved in the liquefied substance A together with water. Next, the liquefied substance A in which water and impurities are dissolved is sent to the evaporator 8 through the valve 12. In the evaporator 8, the energy of the latent heat for vaporizing the liquefied substance A is supplied, and only the liquefied substance A having the lowest boiling point is vaporized, and impurities and water remain. The vaporized substance A is sent to the condenser 9, and the substance A is liquefied by being cooled. The liquefied substance A obtained here is sent again to the treatment tank 2 and used again for desorption of impurities from the adsorbent.

大半 By repeating the cycle of state change of substance A multiple times as necessary, most of the impurities attached to the adsorbent are desorbed. When the desorption is completed, the valve 12 is closed and the liquefied substance A is drawn out from the processing tank 2 by reverse rotation of the pump 1 or a separately prepared drawing pump, and then the valve 15 is opened to reduce the pressure in the processing tank 2 or open it to the atmosphere. Thus, since the liquefied substance A adhering to the adsorbent is vaporized, a regenerated adsorbent close to a new article whose adsorption capacity has been recovered can be obtained.

In this embodiment, the pump 1 is used to circulate the substance A, but the function can be replaced by a compressor. However, since the compressor circulates gas, when used in the present embodiment, it may be installed downstream of the evaporator 8 and upstream of the condenser 9.

FIG. 2 shows another embodiment of the present invention, in which the energy efficiency of the embodiment of FIG. 1 is further enhanced. The operation in the normal sewage treatment mode is the same as that of the embodiment of FIG. 1, and the circulation method of the substance A in the adsorbent regeneration mode is different, except as specifically mentioned.

In the adsorbent regeneration mode, the liquefied substance A discharged from the treatment tank 2 is decompressed by the expansion valve 6, and the pressure and temperature are reduced. Thereafter, the liquefied substance A is vaporized by being guided to the low temperature side of the heat exchanger D7 and exchanged with the high temperature and high pressure substance A flowing on the high temperature side, so that impurities and water are separated. Next, the vaporized substance A is compressed by the compressor 5 to a high temperature and high pressure, led to the high temperature side of the heat exchanger D7, and liquefied by being cooled. The liquefied substance A is cooled by outside air or cooling water in the heat exchanger C34 and sent to the treatment tank 2. The heat exchanger C34 is installed for cooling because the heat generated by the operation of the compressor 5 enters the circulation cycle of the substance A and causes the temperature of the entire circulation system to rise.

As described above, in the present embodiment, since almost the same substance exchanges latent heat of vaporization and latent heat of condensation in the heat exchanger D7 at almost the same flow rate, the energy required for circulation occupies most of the heat and is supplied from the outside. Since the energy to be used is very small, the adsorbent can be regenerated very efficiently.

FIG. 3 shows another embodiment of the present invention, in which the energy efficiency of the embodiment of FIG. 1 is further enhanced. The operation in the normal sewage treatment mode is the same as that of the embodiment of FIG. 1, and the circulation method of the substance A in the adsorbent regeneration mode is different, except as specifically mentioned.

The liquefied substance A discharged from the treatment tank 2 is guided to the low temperature side of the heat exchanger A3, and given the energy of latent heat, the liquefied substance A is vaporized and impurities and water are separated. Next, the vaporized substance A is liquefied by being led to the high temperature side of the heat exchanger B4 and cooled. The liquefied substance A is sent to the treatment tank 2 by the pump 1. On the other hand, the substance B flowing on the high temperature side of the heat exchanger A3 and the low temperature side of the heat exchanger B4 forms a refrigeration cycle. The substance B, which has been compressed by the compressor 5 and becomes high temperature and high pressure, is led to the high temperature side of the heat exchanger A3 and cooled to be liquefied. The liquefied substance A is cooled by the heat exchanger 34 installed in order to prevent the temperature of the circulation system of the refrigeration cycle from being increased, and the pressure is reduced by the expansion valve 6 to become a low temperature and a low pressure. Subsequently, when it is led to the low temperature side of the heat exchanger B4 and heated, it is vaporized and led to the compressor 5.

As described above, in this embodiment, by using the refrigeration cycle of the substance B, only the latent heat of vaporization of the substance A is transferred as the latent heat of condensation of the substance A. Only the power and the power of the compressor 5 are used. Since the temperature difference required for the state change of the substance B may be small, the power of the compressor 5 is very small. Further, the power of the pump 1 is very small because it is only the friction loss of the circulation system. Therefore, the overall energy consumption of the device is the majority of the energy required for circulation, and only a small amount of energy is supplied from the outside, so that the adsorbent can be regenerated very efficiently.

In addition, since substance B only needs to form a refrigeration cycle in a completely closed system, an efficient refrigerant such as chlorofluorocarbon may be used. On the other hand, in the circulation system of the substance A, various impurities dissolve in the substance A. However, if a pump is used for circulation, the performance of the pump is almost unaffected by dissolved impurities, so that the application range can be expanded compared with circulation by a compressor.

FIG. 4 is an embodiment showing the internal structure of the treatment tank 2 in the regeneration mode among the embodiments shown in FIGS. 1 to 3.

The inside of the treatment tank 2 is filled with an adsorbent and a liquefied substance A. However, since the desorption speed of impurities from the adsorbent 50 is slow, the circulation flow rate including vaporization and liquefaction is reduced to reduce the regeneration cost. There is a need. In this case, the substance A passes through the gap between the filled adsorbents 50 and flows out while desorbing impurities, but the path through which the substance A flows through the gap between the adsorbents 50 is biased, and the portion where the desorption speed is low May occur. Therefore, the flow rate in the processing tank 2 is increased by circulating locally through the pump 21, a uniform flow is supplied through the mesh plate 45, and the adsorbent 50 is used as a fluidized bed, thereby improving the contact efficiency with the substance A. As a result, it is possible to improve the playback speed.

FIG. 5 is an embodiment showing the internal structure of the treatment tank 2 in the regeneration mode among the embodiments shown in FIGS. 1 to 3. The adsorbent 50 is filled in the mesh container 40 so that it cannot move inside. In this state, the processing tank 2 is filled with the liquefied substance A, and compressed air is supplied from the lower part of the processing tank 2 through the pipe 41. Since the supplied compressed air becomes bubbles 51 and randomly flows through the gaps of the adsorbent 50, the fresh liquefied substance A is easily supplied, and the regeneration speed can be improved. Moreover, since the position of the adsorbent 50 is fixed by the mesh container 40, it is possible to prevent wear due to movement of the adsorbents 50.

FIG. 6 is an embodiment showing the internal structure of the treatment tank 2 in the regeneration mode among the embodiments shown in FIGS. 1 to 3. The adsorbent 50 is filled in the mesh container 40 so that it cannot move inside, and the treatment tank 2 is filled with the liquefied substance A. A heater 42 is installed in the lower part inside the processing tank 2 so that the substance A can be heated. Since the substance A is maintained at the saturated vapor pressure, all the energy given by the heater 42 is used as latent heat of vaporization. As soon as the substance A is heated by the heater 42, the substance A is vaporized and bubbles 52 of the substance A are generated. Since the bubbles 52 randomly flow through the gaps of the adsorbent 50, the fresh liquefied substance A is easily supplied, and the regeneration speed can be improved. Moreover, since the position of the adsorbent 50 is fixed by the mesh container 40, it is possible to prevent wear due to movement of the adsorbents 50.

Further, if the heater 42 is installed so that the vertical cross-sectional area is larger than the vertical cross-sectional area of the heater 42, the vaporized substance A can be further heated, and the generated bubbles disappear. Can be delayed.

When the impurity of sewage targeted by the present invention is dissolved organic matter, the adsorbent is preferably activated carbon or a derivative thereof. Since activated carbon is hydrophobic, it can efficiently adsorb organic substances in water. In this case, the substance A is preferably dimethyl ether (DME) or a mixture thereof. Since DME has a boiling point of about −24 ° C. and a saturated vapor pressure at 24 ° C. of about 0.58 MPa, it takes a gaseous state at room temperature and normal pressure. Gaseous DME liquefies when cooled or pressurized, but liquefied DME has the property of dissolving water in addition to oil. Therefore, when liquefied DME is used for cleaning activated carbon, it is possible to desorb the impurities after the liquefied DME dissolves water, even if there are impurities covered with moisture on the activated carbon surface, thereby increasing the regeneration efficiency of activated carbon. Can be realized.

FIG. 7 shows an example in which sewage containing dissolved organic matter was purified with activated carbon, and the sewage was treated again with used activated carbon regenerated with DME. In this example, simulated sewage was prepared using an acetic acid aqueous solution having a dissolved organic substance as acetic acid and a concentration of 0.99% as a stock solution. When the stock solution was purified with new activated carbon, the removal rate was 79%. On the other hand, when the used activated carbon was regenerated with DME and used again for purification of the stock solution, the removal rate with regenerated activated carbon was 63%, and the regeneration efficiency in this example was about 80%, and the activated carbon was regenerated with high efficiency. I confirmed that I can do it.

1 Pump 2 Treatment tank 3 Heat exchanger A
4 Heat exchanger B
5 Compressor 6 Expansion valve 7 Heat exchanger D
8 Evaporator 9 Condenser 34 Heat Exchanger C
40 Net-like container 42 Heater 45 Mesh plate 50 Adsorbent 51 Bubble 52 Substance A bubble

Claims

In an adsorbent regenerator that removes adsorbate from a used adsorbent used in water treatment and regenerates it,
Using liquefied substance A that became liquid by holding gaseous substance A at normal temperature and pressure under saturated vapor pressure,
A treatment tank for desorbing adsorbate by bringing the adsorbent into contact with the liquefied substance A and eluting the liquefied substance A;
An evaporator that separates the adsorbate by vaporizing the liquefied substance A in contact with the adsorbent;
A condenser for liquefying the vaporized substance A;
A pump for feeding the liquefied substance A;
An adsorbent regeneration apparatus comprising:
In an adsorbent regenerator that removes adsorbate from a used adsorbent used in water treatment and regenerates it,
Using liquefied substance A that became liquid by holding gaseous substance A at normal temperature and pressure under saturated vapor pressure,
A treatment tank for desorbing adsorbate by bringing the adsorbent into contact with the liquefied substance A and eluting the liquefied substance A;
An evaporator that separates the adsorbate by vaporizing the liquefied substance A in contact with the adsorbent;
A compressor for compressing the vaporized substance A;
A condenser for liquefying the compressed substance A;
An adsorbent regeneration apparatus comprising:
The adsorbent regeneration apparatus according to claim 2,
An adsorbent regenerator comprising a heat exchanger for transferring heat between the substance A on the upstream side and the substance A on the downstream side of the compressor.
In the adsorbent regeneration apparatus according to claim 1 or 2,
An adsorbent regenerator, wherein a high temperature side of the evaporator and a low temperature side of the condenser are connected by a refrigeration cycle using a refrigerant.
The adsorbent regeneration apparatus according to claim 1 or 2, wherein compressed air is injected from a lower part inside the processing tank.
In the adsorbent regeneration apparatus according to claim 1 or 2,
The adsorbent regenerator is controlled so that the adsorbent floats and becomes a fluidized bed by the flow of the substance A in the treatment tank.
In the adsorbent regeneration apparatus according to claim 1 or 2,
An adsorbent regenerator, wherein a heater is installed in the lower part of the treatment tank to boil the substance A under saturated vapor pressure.
The adsorbent regeneration apparatus according to claim 7, wherein
An adsorbent regeneration apparatus, wherein the heater is installed such that a vertical sectional area is larger than a horizontal sectional area.
In the adsorbent regeneration device according to claim 5 or 7,
An adsorbent recycling apparatus, wherein the adsorbent is placed in a net-like container or bag so that the position of the adsorbent particles is not moved by the fluid force of the substance A.
In the adsorbent regeneration apparatus according to claim 1 or 2,
The adsorbent regeneration apparatus, wherein the substance A is dimethyl ether.
In the adsorbent regeneration apparatus according to claim 1 or 2,
An adsorbent regeneration apparatus, wherein the adsorbent is activated carbon or a derivative thereof.