KR102308392B1 - Distillation apparatus including distillation column - Google Patents

Abstract

[Problem] Distillation apparatus provided with a distillation column in which the increase in power consumption of the compression apparatus is prevented even when the concentration of solvent rises to achieve energy saving, and the size of the evaporator is suppressed by compactness of the heat transfer area of the evaporator provides
[Means] The distillation apparatus 1 compresses and heats steam supplied from the distillation column (shelf column or packed column) 2, the reboiler 3, and the top of the distillation column 2 to the reboiler 3 ) and a vapor compressor (4) serving as a heating source. It is comprised so that the steam supplied to the reboiler 3 may heat-exchange and the produced|generated condensed water may return to the tower top of the distillation column 2 as reflux water. The reboiler 3 includes a first evaporative boiler 10A for evaporating and concentrating the supplied storage liquid, and a second evaporating boiler 10B for further evaporating and concentrating the stored liquid concentrated in the first evaporative boiler 10A. are doing

Description

Distillation apparatus including distillation column

The present invention relates to a distillation apparatus having a distillation column, and more particularly, to a distillation column and a reboiler for heating a retentate stored at the bottom of the distillation column, and a distillation column supplied from the top of the column It is related with the energy-saving distillation apparatus provided with the compression apparatus which compresses and heats up vapor|steam and uses it as a heating source of a reboiler.

In a distillation apparatus equipped with a distillation column, in order to achieve energy saving, a vapor compression apparatus functioning as a heat pump is provided, and the vapor from the distillation column is compressed and heated to serve as a heating source for the reboiler. of a distillation apparatus is known (see Patent Document 1 below).

Patent Document 1: Japanese Patent Laid-Open No. 5-237302

In the distillation apparatus like the said prior art example, there is one evaporator used as a reboiler, and when a solvent concentration rises, a boiling point will rise. Therefore, in order to efficiently perform distillation, it is necessary to increase the heat transfer area of the evaporator. If the heat transfer area of the evaporator is enlarged, the size of the evaporator is increased.

Then, even if the solvent concentration rises, the distillation apparatus which suppressed enlargement of an evaporator was desired.

The present invention was conceived in view of the above problems, and its object is to provide a distillation apparatus capable of suppressing enlargement of an evaporator even if the solvent concentration rises.

In order to achieve the above object, the invention according to claim 1 provides a distillation column, a reboiler for heating and evaporating a retentate stored at the bottom of the distillation column, and compressing the vapor supplied from the top of the distillation column. A distillation apparatus comprising: a compression device for heating the reboiler as a heating source; The reboiler is characterized in that it is provided with at least a primary concentrating unit for evaporating and concentrating the supplied reservoir, and a secondary concentrating unit for further evaporating and concentrating the retentate concentrated in the primary concentrating unit.

According to the above configuration, the retentate concentrated in one reboiler (the configuration in which the reboiler is not divided) as in the conventional example becomes high concentration (high boiling point), but in the present invention, the concentrated liquid in the primary concentration section The retentate has a low concentration (low boiling point), and the retentate concentrated in the secondary concentration section has a high concentration (high boiling point). Therefore, in the present invention, compared with the prior art, the primary concentration section can process at a low concentration, and since the boiling point of the liquid to be treated is lowered, the effective heat transfer temperature difference of the reboiler is large, and the heat transfer Since a coefficient also becomes good, enlargement of the heat transfer area of a reboiler can be suppressed.

In addition, since the low-concentration evaporative vapor is supplied to the distillation column, the solvent concentration in the vapor to the distillation column becomes small, and the reflux ratio can be reduced. Moreover, it becomes possible to review the distillation column size small. Moreover, since refluxed water evaporates again in a distillation apparatus, it becomes an evaporation load. Therefore, compared with the prior art, in the present invention, the evaporation load can be reduced and the power consumption can be reduced.

The invention according to claim 2 is a distillation apparatus equipped with the distillation column according to claim 1, wherein the compression apparatus is composed of one compressor, and the vapor compressed by the compressor is applied to the primary and secondary thickening units, respectively. It is characterized in that it is configured to introduce.

The invention according to claim 3 is a distillation apparatus comprising the distillation column according to claim 2, wherein the reboiler is a single horizontal tube type evaporative boiler, the horizontal tube type evaporative boiler is divided into two by a partition, and the two divided evaporative boilers Each divided part of is constituted as the primary and secondary thickening units, and the primary and secondary thickening units include a group of heat transfer tubes through which the vapor compressed in the compressor passes and and a diffuser for dispersing the storage liquid toward the outer surface of the heat transfer tube group, and at one side of the primary and secondary thickening units, an inlet through which steam compressed by the compressor is introduced. A common header on the side is provided to surround one end of each group of heat transfer tubes from the outside, and steam introduced from the common header on the inlet side is provided on the other side surfaces of the primary and secondary thickening units. A common header on the outlet side, in which the condensate generated by heat exchange with the storage liquid dispersed on the outer surface of the heat transfer tube group when passing through the group is stored, surrounding the other end of each heat transfer tube group from the outside, characterized in that .

According to the said structure, the structure which divides one evaporative boiler into two can be used, and compared with Embodiment 1 which uses two evaporative boilers, size reduction of an apparatus and reduction of cost can be aimed at.

The invention according to claim 4 is a distillation apparatus comprising the distillation column according to claim 1, wherein the compression apparatus comprises at least a primary compressor for compressing vapor supplied from the top of the tower of the distillation column; and a secondary compressor for further compressing the vapor, wherein the vapor compressed by the secondary compressor is introduced into the secondary condensing unit, and the vapor compressed in the primary compressor is branched to the primary condensing unit It is characterized in that it is configured to introduce.

According to the above configuration, the retentate heated and evaporated in the secondary condensing unit has a higher concentration than the retentate heated and evaporated in the primary condensing unit. Rather, it is necessary to increase the temperature of the steam supplied to the secondary thickening unit. Therefore, by further compressing and raising the temperature of only the vapor supplied to the secondary condensing unit by the secondary compressor, each of the reservoirs is evaporated with the minimum energy required according to the respective concentrations of the reservoirs in the primary and secondary concentrators. Since it is possible to concentrate, energy saving can be aimed at.

For example, when W1 is the amount of steam required in the primary thickening section and W2 is the amount of steam required in the secondary thickening section, one reboiler (configuration in which the reboiler is not divided) as in the conventional example is used. In the structure to be used, it is necessary to compress the vapor whole quantity (W1+W2) in two stages. On the other hand, in the present invention, only W2 is sufficient for the amount of steam to be compressed in two stages. Therefore, the present invention can achieve energy saving compared to the prior art.

The invention according to claim 5 includes an evaporation step of heating and evaporating a storage liquid stored at the bottom of the distillation column by a reboiler, and compressing the vapor supplied from the top of the distillation column by a compression device, and heating the reboiler A distillation method comprising: a compression step of supplying as a source; It is characterized by comprising a primary concentration step of evaporating and concentrating the supplied retentate, and a secondary concentration step of further evaporating and concentrating the retentate concentrated in the first concentration step.

According to the said structure, the heat transfer area of a reboiler can be made small, and a reflux ratio can be made small. In addition, it becomes possible to review the distillation column size small.

ADVANTAGE OF THE INVENTION According to this invention, even if a solvent concentration rises, enlargement of an evaporator can be suppressed by compaction of the heat transfer area of an evaporator.

1 is an overall configuration diagram of a distillation apparatus according to a first embodiment.
Fig. 2 is an overall configuration diagram of a distillation apparatus according to a second embodiment.
3 is an overall configuration diagram of a distillation apparatus according to a third embodiment.
4 is an overall configuration diagram of a distillation apparatus according to a fourth embodiment.
Fig. 5 is a schematic diagram showing a gas-liquid contact state between a high-concentration generated steam and a low-concentration circulating liquid performed in the first evaporative boiler 10A of the distillation apparatus according to the fourth embodiment;
6 is an overall configuration diagram of a distillation apparatus using an evaporator with a common header.
7 is a perspective view of an evaporator with a common header;
8 is a front view of an evaporator with a common header;
Fig. 9 is an overall configuration diagram of a distillation apparatus according to another modification.
Fig. 10 is an overall configuration diagram of a distillation apparatus according to a conventional example;

EMBODIMENT OF THE INVENTION Hereinafter, this invention is described in detail based on embodiment. In addition, this invention is not limited to the following embodiment.

(Embodiment 1)

BRIEF DESCRIPTION OF THE DRAWINGS It is the overall block diagram of the distillation apparatus which concerns on Embodiment 1. FIG. In the first embodiment, as a distillation apparatus, a distillation apparatus used for the purpose of distilling wastewater containing a high boiling point organic solvent having a higher boiling point than water, and separating the recovered liquid and treated water, Explain. Examples of the high boiling point organic solvent having a higher boiling point than water include NMP (N-methyl-2-pyrrolidone), DMSO (dimethyl sulfoxide), ethylene glycol or diethylene glycol, high boiling point organic solvent. A point alcohol type detergent (surfactant is included) etc. are mentioned.

The distillation apparatus 1 includes a distillation column 2 , a reboiler 3 that heats a retentate stored at the bottom of the distillation column 2 , and steam supplied from the top of the distillation column 2 . A compression device R as a heat pump used as a heat source for the reboiler 3 by compressing and raising the temperature is provided. In the first embodiment, the compression device R is constituted by one vapor compressor 4 . For the distillation column 2, a multi-stage thing may be used, and it is not limited to this, You may use the thing which is not a multi-stage thing. That is, for the distillation column 2, a lathe column or a packed column can be used.

Here, when an outline of the characteristics of the distillation apparatus 1 according to the first embodiment will be described, the reboiler 3 is divided into two, the first evaporative boiler (corresponding to the primary concentrator) 10A and the second While the evaporative boiler (corresponding to the secondary condensing unit) 10B is provided, the concentration of the storage liquid to be evaporated and concentrated in the second evaporative boiler 10B is higher than the concentration of the storage liquid to be evaporated and concentrated in the first evaporative boiler 10A. It is designed to be high. That is, the share of the evaporative concentration unit is divided according to the difference in concentration of the storage liquid subjected to evaporative concentration treatment, and in the case of a low concentration, the first evaporative boiler 10A processes it, and in the case of a high concentration, the second evaporative boiler 10B processes it. has been Specifically, the stock solution is fed into the first evaporative boiler (corresponding to the primary concentrating unit) 10A. On the other hand, the liquid concentrated by the 1st evaporative boiler 10A is injected|thrown-in to the 2nd evaporative boiler (corresponding to the secondary concentrating part) 10B.

By the configuration in which the reboiler 3 is divided in this way, compared to a single case (corresponding to the conventional example without division), the effective heat transfer temperature difference can be large by the minute the boiling point falls. Also, since the heat transfer efficiency is improved, the heat transfer area of the reboiler (evaporator) can be reduced, and the heat transfer area can be made compact.

Hereinafter, the specific structure of the distillation apparatus 1 is demonstrated including the said characteristic structure.

The first evaporative boiler 10A and the second evaporative boiler 10B are both horizontal tube type evaporative boilers and have the same configuration, and the diffusers 11A and 11B, and the indirect heaters 12A and 12B ) is provided. In addition, the 1st evaporative boiler 10A and the 2nd evaporative boiler 10B are not limited to a horizontal tube type, For example, you may use evaporative boilers, such as a thin film flow-down (vertical tube) type.

The indirect heaters 12A and 12B include a heat transfer tube group 13A, 13B composed of one or more horizontal heat transfer tubes, and a pair of left and right headers 14A, 15A; 14B, 15B, have. In addition, the bottom of the evaporative boilers 10A and 10B is a storage part in which the processing liquid is stored. Further, the undiluted solution is supplied to the bottom of the first evaporative boiler 10A through the undiluted solution supply pipe 22 .

The 1st evaporative boiler 10A has the circulation flow path h1 (composed of the pipe|tube 70 and the pipe|tube 71) of the undiluted|stock solution or a concentrate. In the circulation flow path h1, the circulation pump P1 and the diffuser 11A are arrange|positioned. The circulation pump P1 is connected to the bottom of the distillation column 2 . The circulation pump P1 is configured to transfer the stock solution (including the concentrated solution in which the stock solution is concentrated) stored at the bottom of the distillation column 2 to the spreader 11A through the pipe 70 . The diffuser 11A is formed so as to spread the stock solution (including the concentrated solution in which the stock solution is concentrated) from the upper portion of the heat transfer tube group 13A toward the heat transfer tube group 13A. Further, the bottom of the first evaporative boiler 10A is connected to the bottom of the distillation column 2 through a tube 71, and the stored liquid is transferred to the distillation column 2 via the bottom of the first evaporative boiler 10A. is returned to the bottom of the tower, and is stored in the storage chamber (44). Further, the upper part of the first evaporative boiler 10A is connected to the bottom of the distillation column 2 via a tube 72 , and the vapor evaporated as a thin film from the outside of the heat transfer tube group 13A is removed from the distillation column 2 . It is intended to be supplied at the bottom of the tower. In addition, the tube 70 has a branch pipe 73 branched on the way, and the concentrated liquid in which the raw liquid is concentrated from the bottom of the distillation column 2 is transferred through the branch pipe 73 to a second evaporative boiler ( It is designed to be supplied to the bottom of 10B).

In addition, the bottom of the header 14A in the heater 12A is connected to a diffuser 20 provided at the top of the distillation column 2 via a tube 74 . A pump P2 is disposed in the pipe 74, and the condensed water stored in the header 14A by driving the pump P2 is dispersed from the diffuser 20 as reflux water. The pipe 74 has a branch pipe 75 branched on the way, and a part of the condensed water stored in the header 14A is discharged to the outside via the branch pipe 75 .

Moreover, the 2nd evaporative boiler 10B has the circulation flow path h2 of the undiluted|stock solution or a concentrated liquid. In the circulation flow path h2, the circulation pump P3 and the diffuser 11B are arrange|positioned. The circulation pump P3 is connected to the bottom of the second evaporative boiler 10B. The circulation pump P3 is formed so as to be able to transfer the storage liquid (concentrated liquid in which the raw liquid is concentrated) stored in the bottom of the second evaporative boiler 10B to the spreader 11B through the circulation passage h2. . The diffuser 11B is formed so as to spread the storage liquid (the concentrated liquid in which the undiluted solution is concentrated) from the upper part of the heat transfer tube group 13B toward the heat transfer tube group 13B. Further, the upper part of the second evaporative boiler 10B is connected to the bottom of the distillation column 2 via a tube 76 , and the vapor evaporated as a thin film from the outside of the heat transfer tube group 13B is removed from the distillation column 2 . It is intended to be supplied at the bottom of the tower.

Further, the bottom of the header 14B is connected to the bottom of the header 15A via a tube 77, and the condensed water stored in the header 14B is transferred to the header 15A and the heat transfer tube group 13A. Through this, it is supplied to the header 14A and stored therein. In addition, the circulation flow path h2 has a branch pipe 78 branched on the way, and the circulation pump P3 recovers a part of the concentrated solution in which the stock solution is concentrated, and passes through the branch pipe 78 as a recovery solution. (系) It is designed to be discharged outside.

The tower top of the distillation column 2 is connected to the inlet side of the vapor compressor 4 through a tube 79, and the outlet side of the vapor compressor 4 is a header of the heater 12A through a tube 80. (15A) is connected. The pipe 80 is provided with a branch pipe 81 branched on the way, and the outlet side of the steam compressor 4 is also connected to the header 15B of the heater 12B by the branch pipe 31 . Here, the vapor compressor 4 may be any one of a turbo-type vapor compressor, a root-type vapor compressor, or other vapor compressors.

Next, the processing operation of the distillation apparatus 1 of the said structure is demonstrated. By driving the circulation pump P1, the circulating liquid (including the stock solution and the concentrated water) stored in the storage chamber 44 at the bottom of the tower is supplied to the diffuser 11A through the pipe 70, and the diffuser It spreads toward the heat transfer tube group 13A from 11A. The circulating fluid dispersed in the diffuser 11A evaporates as a thin film on the surface of the heat transfer tube group 13A, and steam is generated. This vapor is supplied to the bottom of the distillation column 2 to raise the inside of the distillation column 2 .

On the other hand, the condensed water stored in the header 14A is dispersed from the diffuser 20 as reflux water by driving the pump P2 and flows down the distillation column 2 . Then, at each stage inside the distillation column 2, the vapor rising in the distillation column 2 and the treated water (condensate) flowing down the distillation column 2 are in gas-liquid contact, so that the boiling point These other components are separated, and a liquid with a high boiling point component is concentrated at the bottom of the tower and is stored in the drip storage chamber 44, and vapor mostly composed of low boiling point components is taken out from the top of the tower.

The steam withdrawn from the top of the tower is guided to a steam compressor (4). In the vapor compressor (4), the supplied vapor is compressed and heated, and it is set as the heat source of the reboiler (3). That is, the vapor guided to the vapor compressor 4 is adiabatically compressed in the vapor compressor 4, and after the temperature and pressure rise, it is sent to the headers 15A and 15B.

The vapor entering the header 15A is guided to the inside of the heat transfer tube group 13A, and the circulating fluid dispersed outside the heat transfer tube group 13A is evaporated into a thin film. The vapor generated by thin film evaporation is again supplied to the bottom of the distillation column 2, rises in the distillation column 2, and is in gas-liquid contact with treated water (condensate water) descending from the top of the column into the distillation column 2, , As a result, the high boiling point component concentration in the falling liquid increases, and the high boiling point component concentration in the rising steam decreases. On the other hand, the residual circulating liquid that has not evaporated in the thin film is supplied from the bottom of the first evaporative boiler 10A to the bottom of the distillation column 2 through the tube 71 and is supplied to the storage chamber 44 at the bottom of the column. is held And, by repeatedly performing this series of processes, the circulating liquid is concentrated, and the concentrated liquid is supplied to the bottom of the second evaporative boiler 10B through the branch pipe 73 .

In the second evaporative boiler 10B, by driving the circulation pump P3, the circulating liquid (concentrated liquid in which the raw liquid is concentrated) stored in the bottom of the second evaporating boiler 10B is acidified through the circulation passage h2. It is supplied to the air bag 11B, and is spread|dispersed toward the heat transfer tube group 13B from the air diffuser 11B. On the other hand, the vapor compressed by the vapor compressor 4 enters the header 15B and is guided to the inside of the heat transfer tube group 13B. Thereby, the circulating liquid dispersed by the diffuser 11B evaporates as a thin film on the surface of the heat transfer tube group 13B, and steam is generated. This vapor is supplied to the bottom of the distillation column 2 to raise the inside of the distillation column 2 . On the other hand, the residual circulating liquid that has not evaporated from the thin film is again scattered from the diffuser 11B through the circulation passage h2 to generate steam by evaporation of the thin film. By repeatedly performing this series of processes, the circulating fluid is concentrated and discharged from the pipe 78 as a recovery fluid (concentrate) to the outside of the system.

On the other hand, the condensed water stored in the header 14B is guided to the header 14A through the pipe 77 and the header 15A, and the pump P2 is driven as reflux water to the diffuser 20. It is dispersed from and flows down in the distillation column (2).

In this way, in the present embodiment, the reservoir liquid concentrated in the first evaporative boiler 10A has a low concentration (low boiling point), and the reservoir liquid concentrated in the second evaporative boiler 10B has a high concentration (high boiling point). do. Therefore, in the present embodiment, compared with the conventional example, the first evaporative boiler (corresponding to the primary thickening unit) 10A can process at a low concentration, and the boiling point of the liquid to be treated decreases, so that the reboiler is effective. Since the heat transfer temperature difference can be taken large and a heat transfer coefficient is also improved, enlargement of the heat transfer area of a reboiler can be suppressed.

In addition, since the low-concentration evaporation vapor is supplied to the distillation column 2, the reflux ratio can be reduced. Moreover, since refluxed water evaporates again in a distillation apparatus, it becomes an evaporation load. Therefore, the evaporation load can be made small, and power consumption can be made small.

(Embodiment 2)

2 is an overall configuration diagram of a distillation apparatus according to the second embodiment. In the first embodiment, the compression device is composed of one compressor (4), and the steam compressed by the compressor (4) is introduced into the first evaporative boiler 10A and the second evaporative boiler 10B, respectively. However, in this embodiment, a primary compressor (4A) for compressing the vapor supplied from the top of the column of the distillation column, and a secondary compressor (4B) for further compressing the vapor compressed in the primary compressor (4A), , branching the steam compressed in the secondary compressor 4B and introducing it to the second evaporative boiler 10B via the pipe 40B, and branching the steam compressed in the primary compressor 4A to the pipe ( 40A) is configured to be introduced into the first evaporative boiler 10A.

The operation of the distillation apparatus according to the second embodiment includes further compressing the vapor compressed by the primary compressor 4A in the secondary compressor 4B, and introducing the compressed vapor into the second evaporative boiler 10B. Except for this, the operation of the distillation apparatus according to the first embodiment is the same.

As described above, by further compressing only the steam supplied to the second evaporative boiler 10B by the secondary compressor 4B and raising the temperature, each storage of the first evaporative boiler 10A and the second evaporative boiler 10B Since the storage liquid can each be evaporated and concentrated with the minimum amount of heat required according to the liquid concentration, the power consumption can be reduced and energy saving can be achieved.

For example, when W1 is the amount of steam required by the first evaporative boiler 10A, and W2 is the amount of steam required by the second evaporative boiler 10B, one reboiler (reboiler is divided into a conventional example) In the configuration using the configuration not used), it is necessary to compress the entire amount of steam (W1+W2) in two stages. On the other hand, in the embodiment, the amount of steam to be compressed in two stages is sufficient only with W2. Therefore, the present invention can achieve energy saving compared to the prior art.

(Embodiment 3)

3 is an overall configuration diagram of the distillation apparatus according to the third embodiment. In this Embodiment 3, a reboiler is divided into three, and is provided with the 1st evaporative boiler 10A, the 2nd evaporative boiler 10B, and the 3rd evaporative boiler 10C. In addition, a primary compressor 4A for compressing the vapor supplied from the tower top of the distillation column 2, a secondary compressor 4B for further compressing the vapor compressed in the primary compressor 4A, and a secondary compressor A tertiary compressor (4C) for further compressing the vapor compressed in (4B) is provided, and the vapor compressed in the tertiary compressor (4C) is introduced into the third evaporative boiler (10C) via the tube (40C) In addition, the steam compressed in the secondary compressor 4B is branched and introduced into the second evaporative boiler 10B via the pipe 40B, and the steam compressed in the primary compressor 4A is branched off the pipe ( 40A) is configured to be introduced into the first evaporative boiler 10A. Moreover, the piping state of the periphery of the 2nd evaporative boiler 10B is basically the same as the piping state of the periphery of the 2nd evaporative boiler 10B in Embodiment 1. FIG.

When the boiling point of the storage liquid in the case of the structure which divides a reboiler into two further rises, energy saving is achieved by setting it as the structure which divide|segments a reboiler into three divisions or more like this embodiment.

(Embodiment 4)

4 is an overall configuration diagram of a distillation apparatus according to the fourth embodiment. In the first and second embodiments, the vapor evaporated thinly from the outside of the heat transfer tube group 13B in the second evaporative boiler 10B is supplied to the bottom of the distillation column 2, but in the fourth embodiment, the tube ( 82) is configured to be supplied to the bottom of the first evaporative boiler 10A. With this configuration, in the first evaporative boiler 10A, as shown in FIG. 5 , the high-concentration generated steam E supplied to the bottom and the low-concentration circulating fluid F dispersed from the diffuser 11A are in gas-liquid contact. Thus, the low-concentration circulating liquid F is evaporated to generate low-concentration generated vapor, and evaporation is performed. From the tube 72 , the low-concentration generated steam and the high-concentration generated steam after gas-liquid contact flow out and are supplied to the bottom of the distillation column 2 . As described above, in the fourth embodiment, the high concentration generated steam generated in the second evaporative boiler 10B is brought into gas-liquid contact with the low-concentration circulating fluid F in the first evaporative boiler 10A, whereby the solvent concentration in the high-concentration generated steam is By lowering the solvent concentration in the vapor to the distillation column can be lowered.

Moreover, such a structure is applicable also to the distillation apparatus provided with 3 or more evaporation boilers which divided|segmented the reboiler into 3 or more.

(Other matters)

(1) In the first embodiment, two evaporative boilers were provided, but three or more evaporative boilers according to the second and third embodiments may be used.

(2) In the first embodiment, the evaporative boilers 10A and 10B were provided with a pair of left and right headers 14A, 15A; 14B, 15B, but as shown in Figs. 6 to 8, the common headers 14, 15) may be provided. Here, FIG. 6 is an overall configuration diagram of a distillation apparatus using an evaporator with a common header, FIG. 7 is a perspective view of the evaporator with a common header, and FIG. 8 is a front view of the evaporator with a common header. Moreover, FIG. 6 schematically shows the evaporator seen from the direction of arrow A of FIG. In addition, FIG. 1 schematically shows the evaporator seen from the direction of the arrow B of FIG. That is, although the evaporator (evaporation boiler) is schematically shown in both FIG. 6 and FIG. 1, in order to aim at simplification of illustration, in each figure, the viewing direction of the evaporator is changed and shown. In addition, in FIG. 8, piping regarding an evaporator is abbreviate|omitted and shown. Hereinafter, an outline is described with reference to FIGS. 6-8. The evaporator (evaporation boiler) 100 includes a low-concentration evaporator 102A (primary concentrating unit, equivalent to the first evaporating boiler 10A) and a high-concentration evaporating unit 102B (second concentrating unit) by a partition 101. It is divided into two by the 2nd evaporative boiler 10B). A common header 14 is provided on one side of the low concentration evaporator 102A and the high concentration evaporator 102B, and a common header 15 is provided on the other side of the low concentration evaporator 102A and the high concentration evaporator 102B. is provided. The common header 14 is a common header on the inlet side to which the heating steam is supplied, and the common header 15 is a condensate generated by exchanging heat with the circulating liquid distributed outside the group of heat transfer tubes when the heating steam passes through the group of heat transfer tubes. This is a common header on the outlet side where it is stored. In addition, in FIGS. 6 and 7, 80A is a pipe which guides the heated steam from the compressor 4 to the common header 14, and is used instead of the pipes 80 and 81 of FIG.

Thus, in the distillation apparatus shown in FIGS. 6-8, the structure which divides one evaporator into two can be used, and compared with Embodiment 1 which uses two evaporators, size reduction of an apparatus and reduction of cost can be aimed at.

In addition, if one evaporator is divided into two and the header is also divided into two, the primary compressor 4A and the secondary compressor 4B as in the second embodiment are used, and the evaporative boiler 10A is a primary A distillation apparatus configured to supply compressed steam from the compressor 4A and the compressed steam from the secondary compressor 4B (steam obtained by further compressing the compressed steam from the primary compressor 4A) to the evaporative boiler 10B. It is also possible to apply

(3) In the second embodiment, the compression device is constituted of two compressors 4A and 4B and the two compressors 4A and 4B are connected in series. You may comprise so that the compressors 4D and 4E may be connected in parallel. Referring schematically to FIG. 9 , the tower top of the distillation column 2 is connected to the first evaporative boiler 10A via a compressor 4D, and the tower top of the distillation column 2 is a compressor 4E. It is connected to the 2nd evaporative boiler 10B via the. With this configuration, the vapor taken out from the top of the distillation column 2 is individually supplied to the compressors 4D and 4E, respectively, and the temperature is increased by compression in the compressors 4D and 4E. Then, the heated steam from the compressor 4D is supplied to the first evaporative boiler 10A, and the heated steam from the compressor 4E is supplied to the second evaporative boiler 10B. As described above, in the case of serial connection, two-stage compression is performed, but in the case of parallel connection, since only one-stage compression is used, there is a drawback that power consumption is larger in the case of parallel connection than in the case of serial connection. However, even in the case of parallel connection, since the reboiler is divided at least, it has the advantage that energy saving can be achieved compared with the conventional example in which a reboiler is not divided|segmented.

(4) In the above embodiment 1-4, the stock solution was put into the low-concentration reboiler, but the present invention is not limited to this. It is okay to supply it to any one of the departments.

[Example]

Hereinafter, the present invention will be described in more detail by way of Examples. The present invention is not limited in any way by the following examples.

The inventor of the present application has a normal distillation apparatus in which the reboiler shown in Fig. 10 is not divided (hereinafter referred to as "conventional distillation apparatus Y"), and a distillation apparatus according to Embodiment 2 in which the reboiler is divided into two (hereinafter referred to as "conventional distillation apparatus Y"). , referred to as 'the present invention distillation apparatus (X)'), the reflux ratio, heat transfer area of the evaporative boiler, and power consumption of the compressor were calculated under the following conditions, and the results are shown in Table 1.

In addition, the outline|summary of the distillation apparatus Y of the prior art example is demonstrated with reference to FIG. The conventional distillation apparatus Y includes a multi-stage distillation column 2 , a reboiler 3 , and a compression apparatus R as a heat pump. The reboiler 3 is composed of one evaporative boiler 10 . The compression device R consists of two compressors 4 . In other configurations, parts corresponding to the distillation apparatus of Embodiment 2 are denoted by the same reference numerals.

[condition]

Concentration of the storage liquid evaporated by heating in the evaporation boiler 10: 60wt%

Concentration of the storage liquid evaporated by heating in the evaporation boiler (10A): 30wt%

Concentration of the stored liquid evaporated by heating in the evaporating boiler (10B): 60wt%

Amount of stock solution containing MNP: 8500 kg/hr

MNP concentration of stock solution: 16wt%

Concentrate: 2267 kg/hr

MNP concentration of the concentrate: 60wt%

Condensed water: 6233 kg/hr

MNP concentration of condensate: 100ppm or less

In Table 1, the reflux ratio of the conventional distillation apparatus (Y) is A1, the heat transfer area of the conventional example distillation apparatus (Y) is A2 (m ² ), and the power consumption of the compressor of the conventional example distillation apparatus (Y) is A3 (kW) ), the reflux ratio of the distillation apparatus X of the present invention, total) and the power consumption of the compressor of the distillation apparatus X of the present invention (specifically, the sum of the power consumption of the compressor 4A and the power consumption of the compressor 4B) of the present invention.

(Examination of calculation results)

From Table 1, the reflux ratio of the distillation apparatus (X) of the present invention to the reflux ratio of the distillation apparatus (Y) of the conventional example is 0.703, and the heat transfer of the distillation apparatus (X) of the present invention to the heat transfer area of the distillation apparatus (Y) of the prior art example The area is 0.628, and the power consumption of the distillation apparatus X of the present invention relative to the power consumption of the distillation apparatus Y of the conventional example is 0.713. From this, it is recognized that the reflux ratio, the heat transfer area of the evaporative boiler, and the power consumption of the compressor are all smaller in the distillation apparatus X of the present invention than in the distillation apparatus Y in the prior art.

[Industrial Applicability]

INDUSTRIAL APPLICABILITY The present invention can be applied to an energy-saving distillation apparatus in which vapor from the top of a distillation column is reused as a heating source of a reboiler using a vapor compressor.

1: Distillation apparatus 2: Distillation tower
3: Reboiler (horizontal tube heat exchanger) 4: Compressor
4A: Primary compressor 4B: Secondary compressor
10A: 1st evaporative boiler 10B: 2nd evaporative boiler

Claims (7)

A distillation column, a reboiler for heating and evaporating the stored liquid stored at the bottom of the distillation column, and a compression device for compressing and raising the temperature of the vapor supplied from the top of the distillation column to serve as a heating source for the reboiler and a distillation apparatus configured to return the condensed water generated by heat exchange of the steam supplied to the reboiler to the top of the distillation column as reflux water,
The reboiler includes at least a primary concentrating unit for evaporating and concentrating the supplied retentate, and a secondary concentrating unit for further evaporating and concentrating the retentate concentrated in the primary concentrating unit,
Between the distillation column and the reboiler, a distillation column, characterized in that it has a pipe for supplying the retentate stored at the bottom of the distillation column to the primary and secondary enrichment units of the reboiler, respectively. distillation apparatus. The method according to claim 1,
A distillation apparatus having a distillation column in which the retentate stored at the bottom of the distillation column is supplied to the primary and secondary concentrating units of the reboiler in a liquid state. 3. The method according to claim 2,
A distillation apparatus having a distillation column having a tube for returning the retentate supplied to the primary condensing unit of the reboiler to the bottom of the distillation column. 4. The method according to any one of claims 1 to 3,
The compression device includes a single compressor, and a distillation column having a distillation column configured to introduce vapor compressed by the compressor into the first and second concentration sections, respectively. A distillation column, a reboiler for heating and evaporating the retentate stored at the bottom of the distillation column, and a compression device for compressing and increasing the temperature of vapor supplied from the top of the column of the distillation column as a heating source for the reboiler, A distillation apparatus configured to return condensed water produced by heat exchange of supplied steam to the top of the distillation column as reflux water,
The reboiler includes at least a primary concentrating unit for evaporating and concentrating the supplied reservoir, and a secondary concentrating unit for further evaporating and concentrating the retentate concentrated in the primary concentrating unit,
The compression device is composed of one compressor, and is configured to introduce the vapor compressed in the compressor into the first and second concentrators, respectively,
The reboiler is one horizontal tube type evaporative boiler, and the horizontal tube type evaporative boiler is divided into two by a partition, and each divided part of the two divided evaporative boiler is configured as the first concentrating part and the second concentrating part, ,
The primary and secondary thickening units include a group of heat transfer tubes through which the vapor compressed by the compressor passes, and a diffuser for dispersing the storage liquid toward the outer surface of the group of heat transfer tubes, ,
A common header on an inlet side into which steam compressed by the compressor is introduced is provided on one side of the primary condensing unit and the secondary concentrating unit to surround one end of each heat transfer tube group from the outside, and the primary On the other side of the concentrating unit and the secondary concentrating unit, the condensate generated by heat exchange with the storage liquid dispersed on the outer surface of the heat transfer tube group when the steam introduced from the common header on the inlet side passes through the heat transfer tube group is stored. A distillation apparatus with a distillation column, wherein a common header on the outlet side is provided to surround the other end of each heat transfer tube group from the outside. 4. The method according to any one of claims 1 to 3,
The compression device includes at least a primary compressor for compressing the vapor supplied from the top of the tower of the distillation column, and a secondary compressor for further compressing the vapor compressed in the primary compressor,
Distillation having a distillation column configured to introduce the vapor compressed by the secondary compressor into the secondary thickening unit, and branch the vapor compressed by the primary compressor and introduce it into the primary enrichment unit Device. An evaporation step of heating and evaporating the stored liquid stored at the bottom of the column of the distillation column by means of a reboiler; , A distillation method comprising a reflux water supply step of returning the condensed water generated by heat exchange of the steam supplied to the reboiler to the top of the distillation column as reflux water,
The evaporation step comprises at least a first concentration step of evaporating and concentrating the supplied retentate and a second concentration step of further evaporating and concentrating the retentate concentrated in the first concentration step. .

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