JP2022128038A - Distillation device including distillation tower - Google Patents

Abstract

To provide a distillation device which prevents a reboiler from coming to be considered as a pressure container and prevents size increase of a distillation tower.SOLUTION: A distillation device 1 includes a distillation tower and comprises: a distillation tower 2; a reboiler 3 which heats and evaporates a storage liquid stored at a tower bottom part of the distillation tower 2; and a first steam compression device 4 which compresses steam generated by the reboiler 3 and sends the steam to the distillation tower 2. Preferably, the distillation device 1 includes a second steam compression device 42 which compresses and heats steam supplied from a tower top part of the distillation tower 2 to use the steam as a heating source of the reboiler 3.SELECTED DRAWING: Figure 1

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distillation apparatus provided with a distillation column, and more particularly to a distillation apparatus provided with a distillation column and a reboiler for heating a liquid stored at the bottom of the distillation column.

As a distillation apparatus equipped with a distillation column, there is generally a device in which the liquid stored at the bottom of the distillation column is taken out and most of it is evaporated in a reboiler to be fractionated vapor in the distillation column. known (see Patent Document 1 below).

JP 2017-192868 A

In a distillation apparatus such as the above conventional example, as the solvent concentration of the concentrated liquid is increased in the reboiler (or the evaporator used as the reboiler), the boiling point increases, and when it rises above a certain level, this reboiler corresponds to a pressure vessel. Then, legal inspection becomes necessary, or an approved factory is required to manufacture the pressure vessel. Therefore, it is conceivable to reduce the pressure in the system so that the reboiler does not correspond to the pressure vessel. However, according to such a method, the specific volume (m ³ /kg) of steam increases and the flow velocity of steam in the distillation column increases, so the diameter (barrel diameter) of the distillation column increases, and the initial cost increases accordingly. I had a problem with the increase.

The present invention has been devised in view of the above problems, and its object is to provide a distillation apparatus in which the reboiler does not correspond to the pressure vessel and the size of the distillation column does not increase. .

In order to achieve the above object, a distillation apparatus equipped with a distillation column according to the first aspect of the invention comprises a distillation column, a reboiler for heating and evaporating a liquid stored in the bottom of the distillation column, and the reboiler and a first vapor compression device for compressing the vapor generated in and sending it to the distillation column.

According to the above configuration, by compressing the steam generated in the reboiler with the first steam compression device, the pressure of the reboiler (and the temperature of the circulating fluid) can be lowered, so that the reboiler does not correspond to the pressure vessel. can be done. In addition, since the pressure of the reboiler can be lowered, the pressure resistance design conditions of the reboiler can be lowered (for example, the plate thickness of the reboiler can be reduced, etc.), so there is the advantage that the cost of the reboiler itself can be reduced. can get.
In addition, by compressing with the first vapor compression device, it is possible to suppress an increase in the specific volume of the vapor, so it is possible to suppress an increase in the flow velocity of the vapor in the distillation column. (Body diameter) does not increase, and therefore an increase in cost can be suppressed.

A distillation apparatus equipped with the distillation column according to the invention of claim 2 is a distillation apparatus equipped with the distillation column according to the invention of claim 1, wherein the stored liquid supply pipe supplies the stored liquid to the reboiler. It is characterized by having a path.

A distillation apparatus comprising the distillation column according to the invention of claim 3 is a distillation apparatus comprising the distillation column according to the invention of claim 1 or 2, wherein steam supplied from the top of the distillation column is provided with a second vapor compression device that compresses and heats up and uses as a heat source for the reboiler.

According to the above configuration, the vapor supplied from the top of the distillation column can be reused as a heating source for the reboiler, and the energy saving of the distillation apparatus can be achieved accordingly.

A distillation apparatus comprising a distillation column according to the invention of claim 4 is a distillation apparatus comprising the distillation column according to any one of claims 1 to 3, wherein the reboiler is It is characterized by comprising at least a primary concentration section for evaporatively concentrating the supplied reservoir liquid, and a secondary concentration section for further evaporatively concentrating the reservoir liquid concentrated by the primary concentration section.

In the above configuration, the reservoir liquid concentrated in the primary concentration section has a low concentration (low boiling point), and the reservoir liquid concentrated in the secondary concentration section has a high concentration (high boiling point). Therefore, compared to a configuration with only one reboiler (a configuration in which the reboiler is not divided), a lower concentration can be processed in the primary concentration section, and the boiling point of the liquid to be processed is lowered, so the effective heat transfer temperature of the reboiler is Since a large difference can be obtained and the heat transfer coefficient is improved, an increase in the heat transfer area of the reboiler can be suppressed. In addition, since low-concentration evaporated 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. Also, it becomes possible to reconsider the size of the distillation column to be smaller. In addition, since the reflux water is evaporated again in the distillation apparatus, it becomes an evaporation load. Therefore, compared with a configuration having only one reboiler, this configuration can reduce the evaporation load and power consumption. (See JP-A-2017-192868)

A distillation apparatus equipped with the distillation column according to the invention of claim 5 is a distillation apparatus equipped with the distillation column according to the invention of claim 4, wherein the first vapor compression device is a secondary steam of the reboiler. It is characterized in that the vapor generated in the enrichment section is compressed and sent to the distillation column.

In the case where the reboiler has a configuration in which the primary concentration section and the secondary concentration section are provided, the concentration of the retained liquid concentrated in the secondary concentration section is particularly high (high boiling point) as described above. By compressing the steam generated in the first steam compression device according to the present invention, the effect of the present invention can be exhibited even more than in the case of the configuration having only one reboiler.

A distillation apparatus equipped with the distillation column according to the invention of claim 6 is a distillation apparatus equipped with the distillation column according to the invention of claim 4 or 5, wherein the reboiler is one horizontal tube type evaporator. The horizontal tube type evaporator is divided into two parts by a partition plate, and the divided parts of the evaporator are configured as the primary enrichment part and the secondary enrichment part, and the primary enrichment part and the secondary enrichment part The secondary enrichment section includes a heat transfer tube group through which the steam supplied from the top of the distillation column passes, and a spreader that spreads the stored liquid toward the outer surface of the heat transfer tube group, and the primary enrichment section and on one side of the secondary enrichment section, a common header on the inlet side into which the steam supplied from the top of the distillation column is introduced surrounds one end of each of the heat transfer tube groups. On the other side of the primary enrichment section and the secondary enrichment section, the steam introduced from the common header on the inlet side is sprayed on the outer surface of the heat transfer tube group when passing through the heat transfer tube group. A common header on the outlet side, in which condensate generated by heat exchange with the stored liquid is stored, is provided so as to surround the other end of each of the heat transfer tube groups.

According to the above configuration, it is possible to use a configuration in which one evaporator is divided into two, and it is possible to reduce the size and cost of the device compared to a configuration using two evaporators.

A distillation apparatus comprising a distillation column according to the invention of claim 7 is a distillation apparatus comprising the distillation column according to any one of claims 1 to 6, wherein and condensed water generated by heat exchange of the steam thus generated is returned to the top of the distillation column as reflux water.

According to the present invention, the reboiler can be prevented from being a pressure vessel. In addition, the size of the distillation column does not increase, so an increase in cost can be suppressed.

1 is an overall configuration diagram of a distillation apparatus according to Embodiment 1. FIG. FIG. 2 is an overall configuration diagram of a distillation apparatus according to Embodiment 2; FIG. 2 is an overall configuration diagram of a distillation apparatus according to Embodiment 3; The perspective view of the distillation apparatus which concerns on Embodiment 3. FIG. The front view of the distillation apparatus based on Embodiment 3. FIG. The whole block diagram of the distillation apparatus which concerns on another example.

Hereinafter, the present invention will be described in detail based on embodiments. It should be noted that the present invention is not limited to the following embodiments.

(Embodiment 1)
FIG. 1 is an overall configuration diagram of a distillation apparatus 1 according to Embodiment 1. FIG. In the first embodiment, as the distillation apparatus 1, a distillation apparatus used for distilling waste water containing a high boiling point organic solvent having a boiling point higher than that of water and separating it into a recovered liquid and treated water will be described. Examples of high-boiling organic solvents having a boiling point higher than that of water include NMP (N-methyl-2-pyrrolidone), DMSO (dimethylsulfoxide), ethylene glycol or diethylene glycol, and high-boiling alcohol-based detergents (including surfactants). is mentioned.

The distillation apparatus 1 includes a distillation column 2, a reboiler 3 that heats and evaporates a liquid stored in the bottom of the distillation column 2, and a first vapor compressor that compresses the vapor generated in the reboiler 3 and sends it to the distillation column 2. 4. In Embodiment 1, the first vapor compression device 4 is composed of one vapor compressor. As the distillation column 2, a multi-stage one may be used, or a non-multi-stage one may be used without being limited to this. That is, the distillation column 2 can be a plate column or a packed column.

A reboiler (evaporator) 3 is composed of a horizontal tube type evaporator 10 , and is provided with a spreader 11 and an indirect heater 12 . Note that the evaporator 10 is not limited to the horizontal tube type, and for example, a thin-film flow down (vertical tube) type evaporator may be used.

The indirect heater 12 includes a heat transfer tube group 13 consisting of one or more horizontal heat transfer tubes, and a pair of left and right headers 14 and 15 . Also, the bottom of the evaporator 10 serves as a storage section in which the processing liquid is stored. The undiluted solution is supplied to the bottom of the evaporator 10 through the undiluted solution supply pipe 22 .

The evaporator 10 has a circulation flow path h1 (composed of pipes 70 and 71) for the undiluted solution or the concentrated solution. A circulation pump P1 and a sprayer 11 are arranged in the circulation flow path h1. A circulation pump P1 is connected to the bottom of the distillation column 2 . The circulating pump P1 is formed so as to be able to transfer the undiluted liquid (including the concentrated liquid obtained by concentrating the undiluted liquid) stored at the bottom of the distillation column 2 to the sprayer 11 through the pipe 70 . In other words, the pipe 70 serves as a reservoir liquid supply line that supplies the reservoir liquid stored in the bottom of the distillation column 2 to the reboiler 3 . In addition, the pipe 70 has a branch pipe 83 branched on the way, and a part of the concentrated liquid obtained by concentrating the stock solution is recovered, and can be discharged outside the system as a recovered liquid through the branch pipe 83. ing. The sprayer 11 is formed to spray the undiluted solution (including the concentrate obtained by concentrating the undiluted solution) from above the heat transfer tube group 13 toward the heat transfer tube group 13 . Further, the bottom of the evaporator 10 is connected to the bottom of the distillation column 2 through a pipe 71, and the stored liquid is returned to the bottom of the distillation column 2 through the bottom of the evaporator 10 and returned to the storage chamber 44. It is designed to be stored.

Also, the bottom of the header 14 in the heater 12 is connected through a pipe 74 to the diffuser 20 provided in the upper part of the distillation column 2 . A pump P2 is arranged in the pipe 74, and the condensed water stored in the header 14 is sprayed from the sprayer 20 as recirculated water by driving the pump P2. The pipe 74 has a branch pipe 75 branched on the way, and part of the condensed water stored in the header 14 is discharged to the outside through the branch pipe 75 .

The top of the distillation column 2 is connected to the header 15 of the heater 12 via a pipe 79 so that the vapor supplied from the top of the distillation column 2 is introduced into the header 15.

The upper portion (downstream side) of the evaporator 10 is connected to the inlet side of the first vapor compression device 4 via a pipe 72, and the outlet side of the first vapor compression device 4 is connected to the bottom of the distillation column 2 via a pipe 84. , and the vapor that is thin-film evaporated outside the heat transfer tube group 13 is compressed by the first vapor compressor 4 and supplied to the bottom of the distillation column 2 . Here, the first steam compressor 4 may be a turbo steam compressor, a Roots steam compressor, or any other steam compressor.

Next, the processing operation of the distillation apparatus 1 having the above configuration will be described. By driving the circulating pump P1, the circulating liquid (including the undiluted liquid and the concentrated water) stored in the storage chamber 44 at the bottom of the column is supplied to the spreader 11 through the pipe 70, and from the spreader 11 toward the heat transfer tube group 13. are dispersed. The circulating liquid sprayed by the sprayer 11 evaporates as a thin film on the surface of the heat transfer tube group 13 to generate steam. This vapor is compressed by the first vapor compression device 4 , supplied to the bottom of the distillation column 2 , and ascends inside the distillation column 2 .

On the other hand, the condensed water stored in the header 14 is sprayed from the sprayer 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 steam rising in the distillation column 2 and the treated water (condensed water) flowing down in the distillation column 2 come into gas-liquid contact, whereby components with different boiling points are separated. A concentrated liquid of high boiling point components flows down to the bottom of the column and is stored in the storage chamber 44, and vapor composed mostly of low boiling point components is taken out from the top of the column. Vapor removed from the top of the column is sent to header 15 .

The steam entering the header 15 is guided to the inside of the heat transfer tube group 13 and evaporates the circulating liquid sprayed outside the heat transfer tube group 13 into a thin film. The vapor generated by thin film evaporation is compressed by the first vapor compression device 4 and then supplied to the bottom of the distillation column 2 again to rise inside the distillation column 2, and the treated water (condensation water) and gas-liquid contact, resulting in an increase in the concentration of high boiling point components in the descending liquid and a decrease in the concentration of high boiling point components in the ascending vapor. On the other hand, the remaining circulating liquid that has not undergone thin film evaporation is supplied from the bottom of the evaporator 10 to the bottom of the distillation column 2 through the pipe 71 and stored in the storage chamber 44 at the bottom of the column. The circulating fluid is concentrated by repeating such a series of treatments.

According to Embodiment 1, since the steam generated in the reboiler 3 is compressed by the first steam compression device 4, the pressure in the reboiler 3 can be lowered. Therefore, the reboiler 3 is configured so as not to correspond to a pressure vessel. In addition, since the pressure of the reboiler 3 can be lowered, the pressure resistance design conditions of the reboiler 3 can be lowered (for example, the plate thickness of the reboiler 3 can be reduced, etc.), so the cost of the reboiler 3 itself can be reduced. It is a configuration that can also obtain the advantage of becoming.

In addition, since the specific volume of the vapor can be reduced by compressing it with the first vapor compression device 4, it is possible to suppress an increase in the flow velocity of the vapor in the distillation column 2, so the diameter (barrel diameter) of the distillation column 2 does not become large, and therefore an increase in cost is suppressed.

Specific configurations of other embodiments of the present invention will be described below. In the following description and drawings, the same reference numerals are given to the same parts or members as the parts or members described in the first embodiment, and the description thereof is basically omitted unless necessary. omitted.

(Embodiment 2)
FIG. 2 is an overall configuration diagram of a distillation apparatus 1L according to Embodiment 2. As shown in FIG. In the first embodiment, the reboiler 3 is composed of one evaporator 10, but in the second embodiment, the reboiler 3L is divided into two, the first evaporator (corresponding to the primary concentration section) 10A and the second evaporator. The second evaporator (corresponding to the secondary concentration section) 10B is provided, and the concentration of the stored liquid evaporated and concentrated in the second evaporator 10B is higher than the concentration of the stored liquid evaporated and concentrated in the first evaporator 10A. It is configured. That is, the evaporative concentration part is divided according to the concentration difference of the stored liquid to be evaporatively concentrated, and when the concentration is low, the first evaporator 10A processes it, and when the concentration is high, the second evaporator 10B processes it. is configured as Specifically, the stock solution is put into the first evaporator (corresponding to the primary concentration section) 10A. On the other hand, the liquid concentrated in the first evaporator 10A is put into the second evaporator (corresponding to the secondary concentration section) 10B.

By dividing the reboiler 3L in this way, the effective heat transfer temperature difference can be increased by the amount that the boiling point is lowered compared to the case of a single reboiler (not divided), and the heat transfer efficiency is improved, so the reboiler (evaporator) The heat transfer area can be reduced, and the heat transfer area can be made compact.

The first evaporator 10A and the second evaporator 10B are both horizontal tube type evaporators and have the same configuration, and the first evaporator 10A has the same configuration as the evaporator 10 according to the first embodiment. It has become. Therefore, in the following description, the second evaporator 10B will be basically described. Further, in the first evaporator 10A and the second evaporator 10B, corresponding parts or members are denoted by the same numerals with A and B added.

The first evaporator 10A and the second evaporator 10B are provided with spreaders 11A and 11B and indirect heaters 12A and 12B. The first evaporator 10A and the second evaporator 10B are not limited to horizontal tube type evaporators.

The indirect heaters 12A, 12B include heat transfer tube groups 13A, 13B each composed of one or more horizontal heat transfer tubes, and a pair of left and right headers 14A, 15A; 14B, 15B. Also, the bottoms of the evaporators 10A and 10B serve as reservoirs in which the processing liquid is reserved. The undiluted solution is supplied to the bottom of the first evaporator 10A through the undiluted solution supply pipe 22. As shown in FIG.

The second evaporator 10B has a circulation flow path h2 for the undiluted solution or concentrated solution. A circulation pump P3 and a sprinkler 11B are arranged in the circulation flow path h2. The circulation pump P3 is connected to the bottom of the second evaporator 10B. The circulation pump P3 is formed to transfer the stored liquid (concentrated liquid obtained by concentrating the undiluted liquid) stored in the bottom of the second evaporator 10B to the sprayer 11B through the circulation flow path h2. The sprayer 11B is formed to spray the stored liquid (concentrated liquid obtained by concentrating the stock solution) from above the heat transfer tube group 13B toward the heat transfer tube group 13B.

In addition, the pipe 70 in the circulation flow path h1 of the first evaporator 10A has a branch pipe 73 branched in the middle, and the concentrated liquid obtained by concentrating the raw liquid from the bottom part of the distillation column 2 is passed through the branch pipe 73 to the second 2 It can be supplied to the bottom of the evaporator 10B. In other words, the branch pipe 73, like the pipe 70, also serves as a stored liquid supply pipeline for supplying the stored liquid stored in the bottom of the distillation column 2 to the reboiler 3L.

The upper part of the second evaporator 10B is connected to the inlet side of the first vapor compression device 41 via a pipe 76, and the outlet side of the first vapor compression device 41 is connected to the bottom part of the distillation column 2 via a pipe 85. The vapor that has been thin-film evaporated outside the heat transfer tube group 13B is compressed by the first vapor compression device 41 and supplied to the bottom of the distillation column 2 . Here, the first steam compressor 41 may be a turbo steam compressor, a Roots steam compressor, or any other steam compressor.

The bottom of the header 14B is connected to the bottom of the header 15A through a pipe 77, and the condensed water stored in the header 14B passes through the header 15A and the heat transfer tube group 13A, is supplied to the header 14A, and is stored there. It is designed to be In addition, the circulation flow path h2 has a branch pipe 78 branched on the way. can be discharged to

The top of the distillation column 2 is connected through a pipe 79 to the inlet side of the second vapor compressor 42, and the outlet side of the second vapor compressor 42 is connected through a pipe 80 to the header 15A of the heater 12A. there is The pipe 80 has a branch pipe 81 branched in the middle, and the outlet side of the second vapor compressor 42 is also connected by the branch pipe 81 to the header 15B of the heater 12B. Here, the second vapor compression device 42 may be a turbo-type vapor compressor, a Roots-type vapor compressor, or any other type of vapor compressor.

Next, the processing operation of the distillation apparatus 1L according to Embodiment 2 will be described. The processing operation of the first evaporator 10A is the same as the processing operation of the evaporator 10 according to the first embodiment, and therefore the description is omitted.

Vapor extracted from the top of the distillation column 2 is led to the second vapor compression device 42 . The second vapor compression device 42 compresses and heats the supplied vapor, and uses it as a heat source for the reboiler 3L. That is, the steam led to the second steam compression device 42 is adiabatically compressed by the second steam compression device 42 and sent to the headers 15A, 15B after the temperature and pressure rise.

The steam entering the header 15A is guided to the inside of the heat transfer tube group 13A, and thin-film vaporizes the circulating liquid sprayed on the outside of the heat transfer tube group 13A. The vapor generated by thin-film evaporation is supplied again to the bottom of the distillation column 2, rises in the distillation column 2, and comes into gas-liquid contact with the treated water (condensed water) that descends in the distillation column 2 from the top of the column. As a result, the concentration of high boiling point components in the descending liquid increases and the concentration of high boiling point components in the ascending vapor decreases. On the other hand, the remaining circulating liquid that has not undergone thin-film evaporation is supplied from the bottom of the evaporator 10A to the bottom of the distillation column 2 through the pipe 71 and stored in the storage chamber 44 at the bottom of the column. By repeating such a series of processes, the circulating liquid is concentrated, and the concentrated liquid is supplied through the branch pipe 73 to the bottom of the second evaporator 10B.

In the second evaporator 10B, by driving the circulation pump P3, the circulating liquid (concentrated liquid obtained by concentrating the undiluted liquid) stored at the bottom of the second evaporator 10B is supplied to the sprayer 11B through the circulation flow path h2 and sprayed. It is sprayed from the vessel 11B toward the heat transfer tube group 13B. On the other hand, the steam compressed by the second steam compression device 42 enters the header 15B and is guided inside the heat transfer tube group 13B. As a result, the circulating fluid sprayed by the sprayer 11B evaporates into a thin film on the surface of the heat transfer tube group 13B, generating steam. This vapor is compressed by the first vapor compressor 41 , supplied to the bottom of the distillation column 2 , and ascends inside the distillation column 2 . On the other hand, the remaining circulating liquid that has not undergone thin film evaporation is sprayed again from the sprayer 11B through the circulation flow path h2 to generate steam through thin film evaporation. By repeating such a series of processes, the circulating liquid is concentrated and discharged from the pipe 78 as a recovered liquid (concentrated liquid) to the outside of the system.

On the other hand, the condensed water stored in the header 14B is led to the header 14A through the pipe 77 and the header 15A, and is sprayed from the sprayer 20 as reflux water by driving the pump P2. flow down

Thus, in the second embodiment, the concentration of the stored liquid concentrated in the first evaporator 10A is low (low boiling point), and the concentration of the stored liquid concentrated in the second evaporator 10B is high (boiling point is high). Therefore, in the second embodiment, the first evaporator (corresponding to the primary enrichment section) 10A can process at a lower concentration than in a configuration with only one reboiler (a configuration in which the reboiler is not divided). Since the boiling point of the liquid to be treated is lowered, the effective heat transfer temperature difference in the reboiler can be increased, and the heat transfer coefficient is improved, so the increase in the heat transfer area of the reboiler can be suppressed.

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

In addition, the distillation apparatus 1L according to Embodiment 2 includes the second vapor compression apparatus 42 that compresses and heats the vapor supplied from the top of the distillation column 2 and uses it as a heating source for the reboiler 3L. The steam can be reused as a heating source for the reboiler 3L, and the distillation apparatus 1L is energy-saving accordingly.

In particular, as described above, the stored liquid concentrated in the second evaporator 10B corresponding to the secondary concentration section becomes highly concentrated (high boiling point), and the first vapor compression device 41 is placed above the second evaporator 10B. is connected, the effect of the feature of the present invention, that the steam generated in the reboiler is compressed by the first steam compression device 41, is exhibited more effectively.

That is, in the configuration of the distillation apparatus 1L according to Embodiment 2, as an example (comparative example) for comparison, a configuration without the first vapor compression device 41 is provided, and as shown in FIG. V2 is the pressure (degree of vacuum) in the first evaporator 10A, V10A is the pressure in the first evaporator 10A, V10B is the pressure in the second evaporator 10B, T10A is the circulating liquid temperature in the first evaporator 10A, and T10A is the circulating liquid temperature in the second evaporator 10B. is assumed to be T10B, the following is assumed. When a series of processes are repeated in the distillation apparatus according to this comparative example to concentrate the circulating liquid (concentrated liquid) and increase the solvent concentration, the circulating liquid temperature in the first evaporator 10A is low (for example, T10A = 87.0 ° C.), on the other hand, in the second evaporator 10B, when the boiling point rises to a certain level (for example, T10B=100° C.), the second evaporator 10B corresponds to the pressure vessel. becomes. Therefore, a method of lowering the pressure (degree of vacuum) in the system so that the second evaporator 10B does not correspond to the pressure vessel is also conceivable. In the case of this comparative example, by lowering the pressure (degree of vacuum) in the system measured as V2, V10A, V10B, etc. from (V2=V10A=V10B=) 57.8 kPa to 47.4 kPa, the second 2 Evaporator 10B can be made not to correspond to a pressure vessel. However, such a method increases the specific volume of steam (m ³ /kg). In the case of this comparative example, if the amount of steam passing through the distillation column 2 is assumed to be 1 kg/h, the specific volume of 57.8 kPa is converted to 2.83 m ³ /kg, which does not correspond to the pressure vessel 47 When the pressure is lowered to 0.4 kPa, the specific volume increases from 2.83 m ³ /kg to 3.41 m ³ /kg. As a result, the flow velocity of steam in the distillation column 2 increases, so the diameter (barrel diameter) of the distillation column 2 increases, and the initial cost increases accordingly.

On the other hand, in the distillation apparatus 1L according to Embodiment 2, the first vapor compression device 41 is connected to the upper portion of the second evaporator 10B, and the vapor generated in the second evaporator 10B is compressed into the first vapor compression Since the device 41 is configured to compress, only the pressure V10B of the second evaporator 10B (and the circulating liquid temperature T10B) is lowered to, for example, 47.4 kPa (95.0° C.), thereby increasing the pressure of the second evaporator 10B. It is possible not to apply to the vessel, while the pressure V41 at the outlet side of the first vapor compressor 41 can also be increased, for example, to 57.8 kPa, which is equal to the pressure in the original system (V2=V10A=). Therefore, the specific volume of vapor is not increased, and the diameter (barrel diameter) of the distillation column 2 is not increased.

(Embodiment 3)
3 is an overall configuration diagram of a distillation apparatus 1M according to Embodiment 3, FIG. 4 is a perspective view of distillation apparatus 1M according to Embodiment 3, and FIG. 5 is a front view of distillation apparatus 1M according to Embodiment 3. . 3 schematically depicts the evaporator viewed from the direction of arrow A in FIG. On the other hand, FIG. 5 schematically depicts the evaporator viewed from the direction of arrow B in FIG. That is, both FIGS. 3 and 5 schematically depict the evaporator (evaporator). there is Also, in FIG. 5, the piping related to the evaporator is omitted. An outline will be described below with reference to FIGS. 3 to 5. FIG.

In the second embodiment, the evaporators 10A, 10B are provided with a pair of left and right headers 14A, 15A; 14B, 15B. configuration may be used. The evaporator (evaporator) 100 has a low-concentration evaporator 102A (primary evaporator, equivalent to the first evaporator 10A) and a high-concentration evaporator 102B (secondary evaporator, equivalent to the second evaporator 10B) separated by a partition plate 101. is divided into two. A common header 14C is provided on one side of the low-concentration evaporator 102A and the high-concentration evaporator 102B, and a common header 15C is provided on the other side of the low-concentration evaporator 102A and the high-concentration evaporator 102B. The common header 14C is a common header on the inlet side to which the heating steam is supplied, and the common header 15C exchanges heat with the circulating liquid sprayed outside the heat transfer tube group when the heating steam passes through the heat transfer tube group. It is a common header on the outlet side in which the condensate produced by the 3 and 4, 80A denotes a pipe that guides the heated steam from the second steam compressor 42 to the common header 14C, and is used in place of the pipes 80 and 81 in FIG.

In the distillation apparatus 1M according to Embodiment 3, as shown in FIG. 3, as in the case of the distillation apparatus 1L according to Embodiment 2, the upper part of the secondary enrichment section (high-concentration evaporation section 102B) is , is connected to the inlet side of the first vapor compression device 41 via a pipe 76, the outlet side of the first vapor compression device 41 is connected via a pipe 85 to the bottom of the distillation column 2, and the distillation column 2 is connected via pipe 79 to the inlet side of second vapor compressor 42, and the outlet side of second vapor compressor 42 is connected via pipe 80A to common header 14C.

In this way, in the distillation apparatus 1M shown in FIGS. 3 to 5, a configuration in which one evaporator is divided into two can be used, and compared to Embodiment 2 using two evaporators, the size and cost of the apparatus can be reduced. can be reduced.

If one evaporator is divided into two and the header is also divided into two, for example, as will be exemplified later, a primary compressor and a secondary compressor are used as the second vapor compression device, In a distillation apparatus configured to supply compressed vapor from the primary compressor to the evaporator 10A and compressed vapor from the secondary compressor (vapor obtained by further compressing the compressed vapor from the primary compressor) to the evaporator 10B. It is possible to apply

(Other Matters)
(1) In the second embodiment, the second vapor compression device 42 is composed of one compressor, and the vapor compressed by the second vapor compression device 42 is converted into the first evaporator 10A and the second evaporator 10B. For example, as mentioned in the third embodiment, the second vapor compression device is a primary compressor for compressing the vapor supplied from the top of the distillation column, and a primary A secondary compressor for further compressing the vapor compressed by the compressor, the vapor compressed by the secondary compressor is branched and introduced into the second evaporator 10B through a pipe, and the primary compressor The compressed steam may be branched and introduced into the first evaporator 10A via a pipe. In this configuration, the operation of the distillation apparatus is as follows, except that the vapor compressed by the primary compressor is further compressed by the secondary compressor and this compressed vapor is introduced into the second evaporator 10B. The operation is the same as that of the distillation apparatus 1L according to the second embodiment. In this way, by further compressing only the vapor supplied to the second evaporator 10B by the secondary compressor and raising the temperature, Since each of the stored liquids can be evaporatively concentrated with the minimum necessary amount of heat, power consumption can be reduced, and energy saving can be achieved.

(2) Although one evaporator is provided in the first embodiment and two evaporators are provided in the second embodiment, three or more evaporators may be provided.

Furthermore, for example, when the reboiler is divided into three and includes a first evaporator, a second evaporator, and a third evaporator, a primary compressor for compressing the vapor supplied from the top of the distillation column 2, and a primary Equipped with a secondary compressor that further compresses the vapor compressed by the compressor and a tertiary compressor that further compresses the vapor compressed by the secondary compressor, and the vapor compressed by the tertiary compressor is passed through a pipe. Along with introducing into the third evaporator, the steam compressed by the secondary compressor is branched and introduced into the second evaporator via a pipe, and the steam compressed by the primary compressor is branched and passed through the pipe. It may be configured to be introduced into the first evaporator.

In the case of the above configuration, the first vapor compression device may be provided in any one of the first, second and third evaporators, but is particularly preferably provided in the third evaporator.

(3) In Embodiments 1 to 3 above, the first vapor compression devices 4 and 41 are composed of one vapor compressor, but may be composed of two or more vapor compressors. In this case, the plurality of steam compressors may be connected in series or in parallel. Incidentally, such a configuration is the same as in the case of the second vapor compression device.

(4) In Embodiment 1, the first vapor compression device 4 is provided and the second vapor compression device is not provided, and in Embodiments 2 and 3, the first vapor compression device 41 and the second vapor compression device 42 However, for example, the second vapor compression device may be provided in the first embodiment.

(5) In Embodiments 2 and 3 above, the first vapor compression device 41 is provided above each of the second evaporator 10B and the high-concentration evaporator 102B corresponding to the secondary enrichment section. A first vapor compression device may be provided above the primary enrichment section.

(6) In the second embodiment, the steam that has been thin film evaporated outside the heat transfer tube group 13B in the second evaporator 10B is supplied to the bottom of the distillation column 2. For example, as shown in FIG. Like the distillation apparatus 1N, it may be configured to supply to the bottom of the first evaporator 10A. With such a configuration, in the first evaporator 10A, the high-concentration generated steam supplied to the bottom portion and the low-concentration circulating liquid sprayed from the sprayer 11A come into gas-liquid contact, and the low-concentration circulating liquid evaporates. Low-concentration generated steam is generated by evaporation and condensation is performed. From the pipe 72 , the low-concentration steam and the high-concentration steam after the gas-liquid contact flow out and are supplied to the bottom of the distillation column 2 . In this way, the high-concentration steam generated in the second evaporator 10B is brought into gas-liquid contact with the low-concentration circulating liquid in the first evaporator 10A, thereby reducing the solvent concentration in the high-concentration steam and reducing the distillation column. It is possible to reduce the solvent concentration in the vapor to the

In addition, in the distillation apparatus 1N according to this example, similarly to the distillation apparatus 1L according to the second embodiment, the top portion of the distillation column 2 is connected to the inlet side of the second vapor compression device 42 via the pipe 79. , the outlet side of the second vapor compressor 42 is connected via a tube 80 to the header 15A of the heater 12A, while the upper portion of the second evaporator 10B is connected via a tube 82 to the first vapor compressor. 401, and the outlet side of the first vapor compression device 401 is connected through a pipe 86 to the bottom of the first evaporator 10A. The high-concentration generated steam supplied to the bottom of the first evaporator 10A is supplied to the bottom of the distillation column 2 through the pipe 72 after coming into gas-liquid contact with the low-concentration circulating liquid as described above. That is, the vapor that has been thin film evaporated outside the heat transfer tube group 13B in the second evaporator 10B is compressed by the first vapor compression device 401, and is transmitted through the pipe 86, the first evaporator 10A and the pipe 72 to the distillation column 2. It is designed to be supplied to the bottom of the column.
Moreover, such a configuration can also be applied to a distillation apparatus having three or more evaporators obtained by dividing a reboiler into three or more.

(7) In the above Embodiment 1, the stock solution was put into the reboiler, and in the above Embodiment 2, the stock solution was put into the low-concentration reboiler. may be fed to either of the tops of the columns.

INDUSTRIAL APPLICABILITY The present invention can be applied to a distillation apparatus that includes a distillation column and a reboiler that heats a liquid stored in the bottom of the distillation column.

1: distillation apparatus 2: distillation column 3: reboiler (horizontal tube heat exchanger)
4, 41: First vapor compression device 42: Second vapor compression device

Claims (7)

a distillation column;
a reboiler for heating and evaporating a liquid stored in the bottom of the distillation column;
a first vapor compression device for compressing the vapor generated in the reboiler and sending it to the distillation column;
A distillation apparatus comprising a distillation column, comprising: 2. A distillation apparatus equipped with a distillation column according to claim 1, further comprising a reservoir liquid supply line for supplying said reservoir liquid to said reboiler. 3. A distillation apparatus equipped with a distillation column according to claim 1 or 2, further comprising a second vapor compression device for compressing and raising the temperature of the vapor supplied from the top of said distillation column and using it as a heating source for a reboiler. The reboiler comprises at least a primary concentration section for evaporatively concentrating the supplied reservoir liquid, and a secondary concentration section for further evaporatively concentrating the reservoir liquid concentrated in the primary concentration section. 4. A distillation apparatus comprising the distillation column according to any one of 3. 5. A distillation apparatus equipped with a distillation column according to claim 4, wherein said first vapor compression device is configured to compress the vapor generated in the secondary concentration section of said reboiler and send it to said distillation column. The reboiler is a single horizontal tube type evaporator, and the horizontal tube type evaporator is divided into two by a partition plate, and the two divided parts of the evaporator are divided into the primary concentration section and the secondary concentration section. configured as
The primary enrichment section and the secondary enrichment section include a group of heat transfer tubes through which steam supplied from the top of the distillation column passes, and a spreader that spreads the stored liquid toward the outer surface of the group of heat transfer tubes. with
On one side of the primary enrichment section and the secondary enrichment section, a common header on the inlet side into which steam supplied from the top of the distillation column is introduced extends one end of each of the heat transfer tube groups. On the other side of the primary enrichment section and the secondary enrichment section, the steam introduced from the common header on the inlet side passes through the heat transfer tube group. 3. An outlet-side common header for storing condensed liquid generated by exchanging heat with the stored liquid sprayed on the outer surface is provided so as to surround the other end of each of the heat transfer tube groups. A distillation apparatus comprising the distillation column according to 4 or 5. 7. The steam supplied to the reboiler according to any one of claims 1 to 6, wherein condensed water generated by heat exchange is returned to the top of the distillation column as reflux water. A distillation apparatus with a distillation column.

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