JP2005000860A - Distillation plant and distillation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make reducable the cost of a distillation plant when a component forming an azeotropic mixture is purified and separated. <P>SOLUTION: The distillation plant has a column main body, a first condenser which is connected with the column main body and condenses at least a part of a vapor discharged from the column main body to return it as a first reflux to the column main body, a second condenser which condenses at least a part of the vapor discharged from the column main body into distillate, and a separator which layer-separates the distillate and returns a liquid constituting one layer as a second reflux to the column main body. The amount of the second reflux can be reduced by a portion of the first reflux returned to the column main body. Since the distillate supplied to the separator is reduced, the amounts of cooling water, chilling water, etc., necessary for supercooling the distillate can be reduced. The temperature and flow rate of the cooling water, the chilling water, etc., and the temperature of the distillate can be controlled easily. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a distillation apparatus and a distillation method.
[0002]
[Prior art]
Conventionally, various distillation apparatuses are provided for distilling a stock solution containing a plurality of components to separate each component and recovering a predetermined component as a product.
[0003]
For example, in a stock solution containing three components A to C, the boiling point of component A is lower than the boiling point of component B, the boiling point of component B is lower than the boiling point of component C, When the high-boiling component is constituted by the component C as the boiling component, a two-column distillation column equipped with first and second distillation columns is used. In the first distillation column, component A and components B and C are used. And the mixture is sent to the second distillation column, and component B and component C are separated in the second distillation column.
[0004]
However, when an azeotropic mixture is formed with two of a plurality of components, for example, water and aniline, an azeotropic point is usually formed around 95 [mol%]. In this case, aniline cannot be purified and separated as a pure component.
[0005]
Also, when the volatility values of two components of a plurality of components are close and the relative volatility representing the ratio of each volatility is close to 1, an attempt is made to purify and separate a predetermined component as a pure component Then, since the reflux ratio must be very large, not only the amount of heat to be added to the distillation apparatus becomes extremely large, but also the column diameter and the number of theoretical plates are remarkably increased, resulting in an increase in the cost of the distillation apparatus.
[0006]
Therefore, the azeotrope is distilled off at the top of the first distillation column, the azeotrope is condensed by a condenser, and then sent to a decanter where an upper layer composed of a light liquid and a lower layer composed of a heavy liquid. These are separated into two layers, and one of a light liquid and a heavy liquid is refluxed as a reflux liquid to the first distillation column, and a predetermined component is purified and separated (see, for example, Patent Document 1). .
[0007]
FIG. 2 is a conceptual diagram of a conventional distillation apparatus.
[0008]
In the figure, 201 is a first distillation column, 202 is a second distillation column, 203 and 205 are evaporators, and 204 and 206 are condensers. The first distillation column 201 is composed of a first section 211 to a fifth section 215 formed in order from the top to the bottom of the column, and the second section 212 and the fourth section 214 of which are not shown in the figure. (Ten) material elements are arranged, and a concentration part and a recovery part are formed respectively. The second distillation column 202 includes a first section 216 to a fifth section 220 formed in order from the top to the bottom of the column, and the second section 217 and the fourth section 219 include the first section 216 and the fourth section 219. Filling elements are arranged to form a concentrating part and a collecting part, respectively.
[0009]
The stock solution M is, for example, water as component A, amine as a low-boiling component as component B, aniline as a medium-boiling component as component C, and impurities as a high-boiling component (predetermined components are altered) Formed component) as component D, component A acts as an azeotropic agent, and components A and C form a new azeotrope with a low boiling point. When supplied to the third section 213, the azeotrope and component C have different boiling points and can be separated. In this case, since component A is water and component B is an amine, components A and B are dissolved.
[0010]
The vapor rich in the azeotrope and component B is discharged at the top of the first distillation column 201 and sent to the condenser 204, where it is condensed and converted into liquid and component B of the azeotrope. It becomes a rich liquid mixture, which is discharged from the condenser 204 as distillate and sent to the decanter 222.
[0011]
The decanter 222 separates the distillate into two layers: a lower layer composed of a heavy liquid in which a small amount of components A and B are mixed in component C, and an upper layer composed of a light liquid composed of components A and B. Let Then, almost all of the heavy liquid is refluxed as the reflux liquid to the first distillation column 201, and a part of the heavy liquid is extracted out of the system along the material balance in the distillation apparatus. Further, the light liquid is extracted out of the system along the material balance by the amount mixed in the stock solution M.
[0012]
On the other hand, the liquid rich in components C and D is discharged as bottoms at the bottom of the first distillation column 201, and a part of the bottoms is sent to the evaporator 203 where it is heated. As a result, the vapor rich in components C and D is obtained. The vapor rich in components C and D is circulated to the first distillation column 201, and the remainder of the bottoms is sent to the second distillation column 202.
[0013]
When the bottoms are supplied to the third section 218 in the second distillation column 202, the vapor rich in component C is discharged at the top of the second distillation column 202 and sent to the condenser 206. Then, the liquid is condensed in the condenser 206 to become a liquid rich in component C, and the liquid rich in component C is discharged from the condenser 206 as a distillate. A part of the distillate is refluxed as a reflux liquid into the second distillation column 202, and the remainder of the distillate is extracted out of the system as a product.
[0014]
On the other hand, the liquid rich in component D is discharged as a bottoms at the bottom of the second distillation column 202. A part of the bottoms is sent to the evaporator 205 and heated in the evaporator 205 to become a vapor rich in component D. The vapor rich in component D is sent to the second distillation column 202. It is made to circulate and the remainder of the bottoms is extracted out of the system.
[0015]
[Patent Document 1]
JP-A-9-117602
[0016]
[Problems to be solved by the invention]
However, in the conventional distillation apparatus, when the distillate is sufficiently separated into the upper and lower layers by the decanter 222, the solubility of the heavy liquid in the light liquid or the solubility of the light liquid in the heavy liquid is increased. Since it is necessary to make it low, not only full condensation is performed in the condenser 204, but also the distillate must be supercooled (subcooled) to make the temperature sufficiently low.
[0017]
However, if the temperature is not accurately controlled when the distillate is supercooled, the distillate cannot be sufficiently separated into layers, and components A and B are mixed into component C in the separated heavy liquid. The amount will change. As a result, the composition distribution in the concentrating part of the first distillation column 201 is not normal, and the azeotropic mixture and the component B as the tower top components are mixed into the recovery part, and the distillation apparatus can be operated stably. It becomes impossible.
[0018]
Therefore, it is necessary to control the temperature with high precision. For this reason, it is necessary to control the temperature of the distillate with high precision, which increases the cost of the distillation apparatus.
[0019]
An object of the present invention is to solve the problems of the conventional distillation apparatus and to provide a distillation apparatus and a distillation method capable of reducing the cost when purifying and separating the components forming the azeotrope. To do.
[0020]
[Means for Solving the Problems]
Therefore, in the distillation apparatus of the present invention, a column main body and a first column connected to the column main body and condensed at least a part of the vapor discharged from the column main body are refluxed to the column main body as a first reflux liquid. 1 condenser, a second condenser that condenses at least a part of the vapor discharged from the tower body to form a distillate, and a liquid that forms a layer by separating the distillate into layers. As a second reflux liquid to the tower body.
[0021]
In another distillation apparatus of the present invention, a column main body, a partition partitioning the column main body and forming a first chamber and a second chamber adjacent to each other, and a stock solution are supplied via a feed nozzle, A concentration section formed above the feed nozzle and a distillation section having a recovery section formed below the feed nozzle, a concentration section connected to the distillation section and formed above, and formed below A first distillation unit that is connected to the column main body, condenses at least a part of the vapor discharged from the column main body, and returns to the column main body as a first reflux liquid. A second condenser for condensing at least a part of the vapor discharged from the tower main body to form a distillate, and separating the distillate into layers and separating the liquid constituting one layer into the second And a separator for refluxing the column body as a reflux liquid
[0022]
In still another distillation apparatus of the present invention, a column main body, a partition that divides the column main body and forms a first chamber and a second chamber adjacent to each other, and a stock solution are supplied via a feed nozzle. A first distillation part having a first concentration part formed above the feed nozzle and a first recovery part formed below the feed nozzle; and an upper end of the first distillation part. A second concentrating part connected and formed above the upper end; and a second collecting part formed below the upper end and adjacent to the first concentrating part via a partition. A second concentration section, a third concentration section connected to the lower end of the first distillation section, formed above the lower end, and adjacent to the first recovery section via a partition; and A third distillation section having a third recovery section formed below the lower end; A first condenser connected to the tower main body for condensing at least a part of the vapor discharged from the tower main body and returning to the tower main body as a first reflux liquid; and at least one of the steam discharged from the tower main body. A second condenser for condensing the liquid to form a distillate, a separator for separating the distillate into layers and refluxing the liquid constituting one layer to the tower body as a second reflux liquid, A side cut nozzle that is disposed on the side and discharges the liquid discharged on the tower side as a side cut liquid.
[0023]
In still another distillation apparatus of the present invention, the first condenser further performs cooling with a first cooling medium. Then, in the second condenser, cooling with a second cooling medium having a temperature lower than that of the first cooling medium is performed.
[0024]
In still another distillation apparatus of the present invention, an azeotropic agent is further added. In the separator, the azeotropic agent constitutes the one layer and is recycled.
[0025]
In still another distillation apparatus of the present invention, the distillate is formed by condensing the remaining vapor discharged from the first condenser.
[0026]
In the distillation method of the present invention, at least a part of the vapor discharged from the tower main body is condensed and refluxed to the tower main body as a first reflux liquid, and the vapor discharged from the tower main body A second refluxing step of condensing at least a part into a distillate, separating the distillate into layers, and refluxing the liquid constituting one layer to the tower body as a second reflux liquid.
[0027]
In another distillation method of the present invention, at least a part of the vapor discharged from the column main body is condensed and returned to the column main body as a first reflux liquid, and in the first reflux step, A second refluxing step of condensing the vapor that has not been condensed into a distillate, separating the distillate into layers, and refluxing the liquid constituting one layer to the tower body as a second reflux liquid .
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0029]
FIG. 1 is a conceptual diagram of a distillation apparatus according to the first embodiment of the present invention, and FIG. 3 is a conceptual diagram of a combined distillation column according to the first embodiment of the present invention.
[0030]
In the figure, reference numeral 10 denotes a combined distillation column. The combined distillation column 10 includes a first section 11, a second section 12, a third section 13, a fourth section 14, a fifth section 15, a sixth section 16, It consists of the seventh section 17, the eighth section 18, and the ninth section 19.
[0031]
The column main body of the combined distillation column 10 includes the first chambers 14A to 16A and the second chambers 14B to 16B by the flat partition 22 in the fourth section 14, the fifth section 15 and the sixth section 16. The first chambers 14A to 16A and the second chambers 14B to 16B are adjacent to each other. Further, the first distillation section 25 is formed by the first chambers 14A to 16A, and the second distillation section 26 as another distillation section is formed by the first section 11 to the third section 13 and the second chamber 14B. A third distillation section 27 as another distillation section is formed by the two chambers 15B and 16B and the seventh section 17 to the ninth section 19, respectively.
[0032]
In addition, the said partition 22 can be formed with a heat insulating material, or the inside of the partition 22 can be evacuated, and the partition 22 can also be made into a heat insulation structure. In this case, heat transfer between the first chamber 14A and the second chamber 14B, between the first chamber 15A and the second chamber 15B, and between the first chamber 16A and the second chamber 16B is reduced. Therefore, the efficiency of distillation can be increased.
[0033]
Then, the fifth section 15 is disposed substantially at the center in the height direction of the combined distillation column 10, and the feed nozzle 41 is connected to the first chamber 15A on the side of the column connected to a raw solution supply source (not shown) in the same manner. Side cut nozzles 42 are respectively disposed in the second chamber 15B on the side so as to be connected to a product storage portion (not shown). In the present embodiment, the feed nozzle 41 and the side cut nozzle 42 are disposed at the same height, but may be disposed at different heights.
[0034]
In addition, the first section 11 is disposed at the top of the combined distillation column 10, and the first section 11 is connected to a partial condenser 81 serving as a first condenser so that the steam outlet 43 and the first section 11 are connected. The reflux liquid inlet 44 is connected to a decanter 84 as a separator to form second reflux liquid inlets 48 respectively. The divider 81 and the decanter 84 are connected through a full condenser 83 as a second condenser. In this case, the condenser 81 receives at least an azeotrope-rich vapor and forms at least an azeotrope-rich liquid.
[0035]
Further, a ninth section 19 is disposed at the bottom of the combined distillation column 10, and the ninth section 19 is connected to an evaporator 82 as a heating device and a bottom liquid storage unit (not shown) to be a bottom discharge outlet. 45 and a steam inlet 46 are respectively formed.
[0036]
In operating the distillation apparatus, it is preferable to reduce the combined distillation column 10 under reduced pressure in view of the operation temperature. For this purpose, a vacuum generator (not shown) is connected to the top of the combined distillation column 10. The combined distillation column 10, the partial condenser 81, the evaporator 82, the full condenser 83, the decanter 84, the vacuum generator, and the like constitute a distillation apparatus.
[0037]
In this case, the stock solution M has, for example, water as component A, amine as a low boiling component as component B, aniline as a medium boiling component having a higher boiling point than component B as component C, and boiling point as compared with component C. When an impurity consisting of a high-boiling component is contained as component D, component A acts as an azeotropic agent, and components A and C form a new azeotrope with a low boiling point, the stock solution M passes through line L51. The component C is supplied to the feed nozzle 41, purified and separated as a pure component from the stock solution M in the distillation apparatus, and discharged from the side cut nozzle 42 to the line L56.
[0038]
In the first distillation section 25, the first concentrating section AR1 is formed by the first chamber 14A disposed above the feed nozzle 41 and the first chamber 16A disposed below the feed nozzle 41 is first. Recovery portions AR2 are respectively formed. The second distillation unit 26 is connected to the upper end of the first distillation unit 25, and the second concentration unit AR3 is connected to the first distillation unit by the second section 12 disposed above the upper end. Below the upper end of the part 25, the second recovery part AR4 is formed by the second chamber 14B disposed adjacent to the first concentrating part AR1 via the partition 22 respectively. Further, the third distillation unit 27 is connected to the lower end of the first distillation unit 25, and is disposed adjacent to the first recovery unit AR2 via the partition 22 above the lower end. A third concentrating portion AR5 is formed by the second chamber 16B, and a third recovery portion AR6 is formed by the eighth section 18 disposed below the lower end of the first distillation portion 25.
[0039]
As described above, the upper end of the first distillation unit 25 is substantially at the center in the height direction of the second distillation unit 26, and the lower end of the first distillation unit 25 is substantially at the center in the height direction of the third distillation unit 27. Connected to each.
[0040]
Each of the first to third concentrating parts AR1, AR3, AR5 and each of the first to third collecting parts AR2, AR4, AR6 is formed of a packing element that is composed of one node and filled with a regular packing. However, depending on the relative volatility between the components to be distilled, to ensure the number of theoretical plates required for the distillation, a packing element consisting of several sections corresponding to the characteristics of the packing used is used. It can also be formed. Further, each stage of the combined distillation column 10 can be formed by a bubble bell type tray or the like. A distributor can be disposed between the nodes. The combined distillation column 10 preferably has about 30 to 100 theoretical plates as a whole, and the fourth section 14 and the sixth section 16 are preferably applied with about 5 to 30 stages, respectively.
[0041]
By the way, a laminar collector 54 and a channel distributor 61 are disposed in the third section 13, and the liquid collected by the collector 54 is supplied to the first chamber of the fourth section 14 at a predetermined distribution ratio by the distributor 61. Different amounts are distributed to 14A and the second chamber 14B.
[0042]
Further, a laminar collector 62 is disposed immediately above the feed nozzle 41 in the first chamber 15A of the fifth section 15 and a tubular distributor 63 is disposed immediately below. The liquid collected by the collector 62 is collected by the feed nozzle. Together with the stock solution M supplied via 41, the distributor 63 supplies the first chamber 16 </ b> A of the sixth section 16.
[0043]
On the other hand, a chimney hat type collector 65 is disposed immediately above the side cut nozzle 42 in the second chamber 15B of the fifth section 15 and a tubular type distributor 66 is disposed immediately below. The liquid collected by the collector 65 The cut liquid is discharged from the side cut nozzle 42 and supplied to the second chamber 16 </ b> B of the sixth section 16 by the distributor 66.
[0044]
Further, a laminar collector 67 and a tubular distributor 68 are disposed in the seventh section 17, and the liquid that has moved downward from the sixth section 16 is collected by the collector 67 and then collected by the distributor 68. 8 section 18 is supplied.
[0045]
Next, the operation of the distillation apparatus having the above configuration will be described.
[0046]
First, the stock solution M is supplied from the feed nozzle 41. In this case, as described above, in the stock solution M, the components A and C constitute an azeotropic mixture, and the components A and B are dissolved. The azeotrope has a low boiling point, and the azeotrope and component C have different boiling points and can be separated from each other. Therefore, the stock solution M is gas-liquid separated in the first recovery part AR2, and generates vapor rich in the azeotropic mixture and component B in the upper part and liquid rich in components C and D in the lower part, A liquid rich in components C and D is supplied from the lower end of the first distillation section 25 to the third distillation section 27.
[0047]
The liquid rich in components C and D is heated in the third distillation section 27 to become vapor rich in components C and D, and the vapor rich in components C and D is the first recovery. While being moved upward in the part AR2, it is in contact with the stock solution M and prevents the azeotrope of the stock solution M and the vapor rich in the component B from moving downward.
[0048]
On the other hand, the vapor rich in the azeotropic mixture and the component B moves upward in the first concentrating part AR <b> 1 and is supplied to the second distillation part 26 from the upper end of the first distillation part 25. Further, the vapor rich in the azeotrope and component B is cooled and purified in the second distillation section 26 and condensed to become a liquid rich in the azeotrope, components B and C. A part of the liquid rich in the azeotrope and components B and C is refluxed to the first concentration unit AR1, and the azeotrope and component B that is moved upward in the first concentration unit AR1. Contacted with rich steam.
[0049]
In this way, the vapor rich in the azeotrope and component B is supplied from the upper end of the first distillation section 25 to the second distillation section 26.
[0050]
In the third recovery part AR6, the liquid rich in the components C and D moves downward, and the vapor rich in the component C is generated in the upper part, and the liquid rich in the component D is generated in the lower part. Therefore, the liquid rich in component D is discharged from the bottom liquid outlet 45 to the line L52 as bottom liquid.
[0051]
A part of the bottoms is sent to the evaporator 82 via the line L53, and is heated by the evaporator 82 to become a vapor rich in component D. The steam rich in the component D is sent to the steam inlet 46 through the line L54, and is supplied from the steam inlet 46 to the ninth section 19, and in the ninth section 19 and the third recovery part AR6. While being moved upward, it is in contact with the liquid rich in components C and D and generates a vapor rich in component C from the liquid rich in components C and D. Further, the remainder of the bottoms is supplied to the bottoms storage unit via a line L55.
[0052]
Subsequently, a part of the vapor rich in the component C moves upward in the third concentration unit AR5, and is rich in the component C from the second distillation unit 26 at the upper end of the third distillation unit 27. It comes into contact with a liquid and becomes a liquid rich in component C. In this way, the liquid rich in component C obtained at the upper end of the third distillation section 27 is discharged from the side cut nozzle 42 to the line L56 as a side cut liquid and supplied to the product storage section. .
[0053]
On the other hand, in the second recovery unit AR4 of the second distillation unit 26, the liquid rich in the azeotrope and component B moves downward, and the vapor rich in the azeotrope and component B in the upper direction is moved downward. As a result, liquids rich in component C are generated. In this way, the liquid rich in component C obtained at the lower end of the second distillation section 26 is similarly discharged from the side cut nozzle 42 to the line L56 as a side cut liquid.
[0054]
The vapor rich in the azeotropic mixture and component B moves upward in the second concentrating part AR3, is distilled at the vapor outlet 43, is discharged to a line L57, and is sent to the partial condenser 81. Then, in the first refluxing step, at least a part of the steam is condensed by the first cooling medium, for example, cooling water, by the partial condenser 81, and partial condensation is performed. The azeotrope and component B rich liquid is discharged to line L58 and then sent to the first reflux inlet 44 as the first reflux to increase the efficiency of distillation, the first reflux The mixture is refluxed from the reflux liquid inlet 44 to the second concentrating part AR3 and brought into contact with the azeotrope that is moved upward in the second concentrating part AR3 and the vapor rich in component B.
[0055]
In the second refluxing step, the remaining azeotropic mixture subjected to partial condensation and the vapor rich in component B are discharged from the partial condenser 81 to the line L60, sent to the full condenser 83, All of the steam is condensed by a second cooling medium having a temperature lower than that of the first cooling medium, for example, chiller water, by the contractor 83, and the total shrinkage is performed. The azeotrope formed along with the total shrinkage and the liquid rich in component B are discharged to the line L61 as a distillate and then sent to the decanter 84.
[0056]
The decanter 84 divides the distillate into a single layer consisting of a heavy liquid in which a small amount of components A and B are mixed in the component C, that is, a lower layer and a light liquid consisting of components A and B. The layers are separated into two layers, ie, the upper two layers. In this case, if the decanter 84 is used to sufficiently separate the distillate into two layers, the upper layer and the lower layer, it is necessary to lower the solubility of the heavy liquid in the light liquid or the solubility of the light liquid in the heavy liquid. In the total condenser 83, the distillate is supercooled and the temperature is sufficiently lowered.
[0057]
Then, almost all of the heavy liquid is discharged to the line L62, sent to the second reflux liquid inlet 48 as the second reflux liquid, and refluxed from the second reflux liquid inlet 48 to the second concentration unit AR3. Similar to the first reflux liquid, it is brought into contact with the azeotrope that is moved upward in the second concentration part AR3 and the vapor rich in component B.
[0058]
A part of the heavy liquid is discharged to the line L64 along the material balance in the distillation apparatus, and extracted out of the system. Further, the light liquid is discharged to the line L63 along the material balance by the amount mixed in the stock solution M, and is extracted out of the system.
[0059]
In this case, since the component C is purified and separated from the stock solution M without using a plurality of distillation columns, there is no need to repeat heating and cooling in each of the plurality of distillation columns, and a condenser, an evaporator, There is no need to provide a lot of instrumentation such as pumps. Moreover, not only can the area occupied by the distillation apparatus be reduced, but also the utility usage and energy consumption can be reduced, and the cost of the distillation apparatus can be reduced.
[0060]
For example, when the flow rate of the stock solution M is 1000 kg / h, the stock solution M contains about 95 wt% aniline, about 3 wt% water, and 2 wt% high boilers. When the aniline is purified and separated at 99.9 [% by weight], in the conventional two-column distillation apparatus, the amount of heat of 300,000 [kcal / h] must be added to the distillation apparatus. In this embodiment, it is only necessary to add a heat quantity of 240,000 [kcal / h] to the distillation apparatus, and energy consumption can be reduced by about 20 [%].
[0061]
By the way, in the combined distillation column 10 having the above-described configuration, the amount of the reflux liquid refluxed to the top of the column, that is, the second concentrating part AR3 (hereinafter referred to as “refluxing amount”) is To concentrate the azeotropic mixture and the reflux amount necessary for concentrating the component B, to the reflux amount necessary to discharge the component C as a side cut liquid, and to concentrate the component C in the third concentration unit AR5. It becomes a value obtained by adding the required reflux amount.
[0062]
Accordingly, an excessive amount of the reflux liquid is refluxed in the second concentration part AR3, but the component A in the reflux liquid is recovered in the second recovery part AR4 and thus mixed in the side cut liquid. There is nothing.
[0063]
As described above, in the combined distillation column 10, it is necessary to increase the reflux amount as compared with the two-column distillation column, but the first reflux liquid is refluxed from the partial condenser 81 to the second concentration unit AR 3. Accordingly, the amount of the second reflux liquid refluxed from the decanter 84 to the second concentration unit AR3 can be reduced.
[0064]
By the way, if the distillate is sufficiently separated into the heavy liquid and the light liquid in the decanter 84, it is necessary to reduce the solubility of the heavy liquid in the light liquid or the solubility of the light liquid in the heavy liquid. The effluent must be supercooled to reduce the temperature sufficiently. In addition, it is necessary to accurately control the temperature and flow rate of cooling water, chiller water, and the like, and the temperature of the distillate.
[0065]
However, as described above, the amount of the distillate supplied to the decanter 84 is reduced by the amount that the first reflux solution is refluxed to the second concentration unit AR3. The amount of necessary cooling water, chiller water, etc. can be reduced. Therefore, the cost of the distillation apparatus can be reduced. In addition, since the temperature and flow rate of cooling water, chiller water, etc., and the temperature of the distillate can be easily controlled, the degree of freedom in the design and operation of the distillation apparatus can be increased.
[0066]
The azeotropic mixture and the liquid rich in component B formed along with the partial contraction are refluxed from the first reflux liquid inlet 44 to the second concentration unit AR3 without separating the layers. The composition distribution of the concentrated part AR3 can be maintained normally. Therefore, a sufficient amount of reflux liquid can be secured.
[0067]
By the way, in this embodiment, water is contained as an azeotropic agent in the stock solution M, but a second embodiment in which a predetermined azeotropic agent is added to the stock solution M will be described.
[0068]
FIG. 4 is a conceptual diagram of a distillation apparatus in the second embodiment of the present invention.
[0069]
In this case, the stock solution M contains water as component A, acetic acid composed of medium boiling components as component C, and impurities composed of high boiling components as component D. By the way, since the normal boiling points of water and acetic acid are 100 [° C.] and 118.1 [° C.], respectively, components A and C can be separated by an ordinary distillation method. Since the relative volatility of is close to 1, when the component C is purified and separated as a pure component, the reflux ratio must be very large. Therefore, not only the amount of heat to be added to the distillation apparatus is extremely increased, but also the column diameter and the number of theoretical plates are remarkably increased, and the cost of the distillation apparatus is increased.
[0070]
Therefore, when butyl acetate, which is a low-boiling component, is added as component B, component B acts as an azeotropic agent, and a new azeotropic mixture having a low boiling point is formed by components A and B. In this case, when the stock solution M is supplied to the feed nozzle 41, the component C is purified and separated from the stock solution M as a pure component in the distillation apparatus. The stock solution M often contains a small amount of low-boiling components.
[0071]
Then, the first section 11 (FIG. 3) is connected to a partial condenser 81 as a first condenser and connected to a vapor outlet 43 and a first reflux liquid inlet 44, and an azeotropic agent supply source (not shown). A second reflux liquid inlet 48 is formed by connecting to an azeotropic agent inlet 47 and a decanter 94 as a separator, and component B is supplied from the azeotropic agent supply source via line L66. It is supplied to the inlet 47 and added to the stock solution M in the combined distillation column 10. In the present embodiment, the azeotropic agent inlet 47 is formed at the top of the column, but can be formed at another predetermined location of the combined distillation column 10. It can also be added to the stock solution M in the line L51.
[0072]
Since water and butyl acetate hardly dissolve, the azeotrope is a multiphase azeotrope having a boiling point of 90.2 [° C.].
[0073]
Next, the operation of the distillation apparatus having the above configuration will be described.
[0074]
First, when the stock solution M is supplied from the feed nozzle 41 and the component B is supplied from the azeotropic agent inlet 47, the stock solution M and the component B are mixed, and an azeotrope is formed by the components A and B. . Then, gas-liquid separation is performed in the first recovery unit AR2, and vapor rich in the azeotrope and component C is generated in the upper portion, and liquid rich in components C and D is generated in the lower portion. A rich liquid is supplied to the third distillation unit 27 from the lower end of the first distillation unit 25.
[0075]
The liquid rich in components C and D is heated in the third distillation section 27 to become vapor rich in components C and D, and the vapor rich in components C and D is the first recovery. While being moved upward in the part AR2, it contacts the azeotrope and the liquid rich in component C and prevents the azeotrope and vapor rich in component C from moving downward.
[0076]
On the other hand, the vapor rich in the azeotrope and component C moves upward in the first concentrating part AR1, and is supplied to the second distilling part 26 from the upper end of the first distilling part 25. Further, the vapor rich in the azeotrope and component C is cooled and condensed in the second distillation section 26 to become a liquid rich in the azeotrope and component C. Then, a part of the liquid rich in the azeotrope and component C is refluxed to the first concentration unit AR1, and is rich in the azeotrope and component C that is moved upward in the first concentration unit AR1. Contacted with steam.
[0077]
In this way, the vapor rich in the azeotrope and component C is supplied from the upper end of the first distillation unit 25 to the second distillation unit 26.
[0078]
In the third recovery part AR6, the liquid rich in the components C and D moves downward, and the vapor rich in the component C is generated in the upper part, and the liquid rich in the component D is generated in the lower part. Therefore, the liquid rich in component D is discharged from the bottom liquid outlet 45 to the line L52 as bottom liquid.
[0079]
A part of the bottoms is sent to an evaporator 82 as a heating device via a line L53, and is heated by the evaporator 82 to become a vapor rich in component D. The steam rich in the component D is sent to the steam inlet 46 through the line L54, and is supplied from the steam inlet 46 to the ninth section 19, and in the ninth section 19 and the third recovery part AR6. While being moved upward, it is in contact with the liquid rich in components C and D and generates a vapor rich in component C from the liquid rich in components C and D. Further, the remainder of the bottoms is supplied to the bottoms storage unit via a line L55.
[0080]
Subsequently, a part of the vapor rich in the component C moves upward in the third concentration unit AR5, and is rich in the component C from the second distillation unit 26 at the upper end of the third distillation unit 27. It comes into contact with a liquid and becomes a liquid rich in component C. In this way, the liquid rich in component C obtained at the upper end of the third distillation section 27 is discharged from the side cut nozzle 42 to the line L56 as a side cut liquid and supplied to the product storage section. .
[0081]
On the other hand, in the second recovery unit AR4 of the second distillation unit 26, the liquid rich in the azeotrope and the component C moves downward, and the vapor rich in the azeotrope moves upward as it goes downward. A liquid rich in component C is generated. In this way, the liquid rich in component C obtained at the lower end of the second distillation section 26 is similarly discharged from the side cut nozzle 42 to the line L56 as a side cut liquid.
[0082]
The vapor rich in the azeotropic mixture moves upward in the second concentrating part AR3, is distilled at the vapor outlet 43, is discharged to the line L57, and is sent to the partial condenser 81. In the first refluxing step, the partial condenser 81 condenses a part of the steam with a first cooling medium, for example, cooling water. Next, after the liquid rich in the azeotrope formed along with the partial condensation is discharged to the line L58, the first reflux liquid is introduced into the first reflux liquid inlet 44 in order to increase the efficiency of distillation. And is refluxed from the first reflux liquid inlet 44 to the second concentrating part AR3 and brought into contact with the vapor rich in the azeotrope that is moved upward in the second concentrating part AR3.
[0083]
Further, the remaining vapor rich in the azeotrope that has not been condensed is discharged from the partial condenser 81 to the line L60 and sent to the full condenser 83 as the second condenser. Is condensed by a second cooling medium having a temperature lower than that of the first cooling medium, for example, chiller water, and the total shrinkage is performed. The liquid rich in the azeotropic mixture formed along with the total shrinkage is discharged to the line L61 as a distillate, and then sent to a decanter 94 as a separator.
[0084]
In the second refluxing step, the decanter 94 is mixed with the distillate as an upper layer composed of a light liquid in which a small amount of the component A is mixed in the component B, and a small amount of the component B in the component A. The layers are separated into two lower layers composed of heavy liquid. In this case, if the decanter 94 is used to sufficiently separate the distillate into two layers, the upper layer and the lower layer, it is necessary to reduce the solubility of the heavy liquid in the light liquid or the solubility of the light liquid in the heavy liquid. In the total condenser 83, the distillate is supercooled and the temperature is sufficiently lowered.
[0085]
Then, all of the light liquid is discharged to the line L62, sent to the second reflux liquid inlet 48 as the second reflux liquid, and refluxed from the second reflux liquid inlet 48 to the second concentrating part AR3. Similar to the reflux liquid of No. 1, it is brought into contact with the vapor rich in the azeotrope that is moved upward in the second concentration part AR3. Along with this, the azeotropic agent is recycled. In this embodiment, the azeotropic agent is supplied as a second reflux liquid into the tower body and circulated, but the azeotropic agent is added to the stock solution M to be supplied into the tower body. And can be circulated.
[0086]
The heavy liquid is discharged to the line L63 along the material balance by the amount mixed in the stock solution M, and is extracted out of the system.
[0087]
In this case, since the component C is purified and separated from the stock solution M without using a plurality of distillation columns, there is no need to repeat heating and cooling in each of the plurality of distillation columns, and a condenser, an evaporator, There is no need to provide a lot of instrumentation such as pumps. Moreover, not only can the area occupied by the distillation apparatus be reduced, but also the utility usage and energy consumption can be reduced, and the cost of the distillation apparatus can be reduced.
[0088]
By the way, in the combined distillation column 10 having the above-described configuration, the reflux amount in the second concentration unit AR3 is set as the side cut liquid to the reflux amount necessary for concentrating the azeotropic mixture in the second concentration unit AR3. This is a value obtained by adding the amount of reflux necessary for discharging the component C and the amount of reflux necessary for concentrating the component C in the third concentration unit AR5.
[0089]
Accordingly, an excessive amount of the reflux liquid is refluxed in the second concentration part AR3, but the component B in the reflux liquid is recovered in the second recovery part AR4, and therefore mixed in the side cut liquid. There is nothing.
[0090]
As described above, in the combined distillation column 10, it is necessary to increase the reflux amount as compared with the two-column distillation column, but the first reflux liquid is refluxed from the partial condenser 81 to the second concentration unit AR 3. Accordingly, the amount of the second reflux liquid refluxed from the decanter 94 to the second concentration unit AR3 can be reduced.
[0091]
By the way, if the distillate is sufficiently separated into the heavy liquid and the light liquid in the decanter 94, it is necessary to reduce the solubility of the heavy liquid in the light liquid or the solubility of the light liquid in the heavy liquid. The effluent must be supercooled to reduce the temperature sufficiently. In addition, it is necessary to accurately control the temperature and flow rate of cooling water, chiller water, and the like, and the temperature of the distillate.
[0092]
However, as described above, the amount of the distillate supplied to the decanter 94 is reduced by the amount that the first reflux solution is refluxed to the second concentration unit AR3. The amount of necessary cooling water, chiller water, etc. can be reduced. Therefore, the cost of the distillation apparatus can be reduced. In addition, since the temperature and flow rate of cooling water, chiller water, etc., and the temperature of the distillate can be easily controlled, the degree of freedom in the design and operation of the distillation apparatus can be increased.
[0093]
By the way, since acetic acid has a boiling point higher than that of water, it is usually necessary to extract component C as a product in a liquid state. In this embodiment, a liquid rich in component C is discharged as a side cut solution. ing. In the combined distillation column 10, since the component D is not concentrated together with the component C in the second recovery part AR4, it is possible to prevent the component D from being mixed into the side cut liquid. Purity can be increased.
[0094]
Therefore, the reflux ratio can be reduced correspondingly, and the amount of heat to be applied to the distillation apparatus can be reduced. Moreover, since the tower diameter and the number of theoretical plates can be reduced, the cost of the distillation apparatus can be reduced.
[0095]
In addition, since it is not necessary to extract steam rich in component C as side cut steam or evaporate the side cut liquid again, not only can the control be simplified, but also the structure of the distillation apparatus can be simplified. And the cost of the distillation apparatus can be reduced.
[0096]
In the present embodiment, a partition 22 is disposed in the center of the tower body, a second concentration unit AR3 is formed above the partition 22, and a third recovery unit AR6 is formed below the partition 22. The upper part of the partition is arranged at the top of the tower, or the lower part of the partition is arranged at the bottom of the tower. Two distillation sections can be formed. In that case, in two distillation parts, a concentration part or a collection | recovery part can also be shared.
[0097]
In this embodiment, a distillation apparatus in which a decanter is connected to a combined distillation column is described. However, the present invention can be a distillation apparatus in which a decanter is connected to a two-column distillation column.
[0098]
In addition, this invention is not limited to the said embodiment, It can change variously based on the meaning of this invention, and does not exclude them from the scope of the present invention.
[0099]
【The invention's effect】
As described above in detail, according to the present invention, in the distillation apparatus, the first reflux is obtained by condensing at least a part of the tower main body and the vapor connected to the tower main body and discharged from the tower main body. A first condenser that is refluxed to the tower body as a liquid; a second condenser that condenses at least part of the vapor discharged from the tower body to form a distillate; and a layer separation of the distillate. And a separator for refluxing the liquid constituting one layer to the column body as a second reflux liquid.
[0100]
In this case, the amount of reflux of the second reflux liquid can be reduced by the amount that the first reflux liquid is refluxed to the tower body.
[0101]
In addition, since the distillate supplied to the separator is reduced by the amount that the first reflux is refluxed to the tower body, the amount of cooling water, chiller water, etc. necessary for supercooling the distillate Can be reduced.
[0102]
As a result, the cost of the distillation apparatus can be reduced in purifying and separating the components forming the azeotrope.
[0103]
In addition, since the temperature and flow rate of cooling water, chiller water, etc., and the temperature of the distillate can be easily controlled, the degree of freedom in the design and operation of the distillation apparatus can be increased.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram of a distillation apparatus in a first embodiment of the present invention.
FIG. 2 is a conceptual diagram of a conventional distillation apparatus.
FIG. 3 is a conceptual diagram of a combined distillation column in the first embodiment of the present invention.
FIG. 4 is a conceptual diagram of a distillation apparatus in a second embodiment of the present invention.
[Explanation of symbols]
10 Combined distillation tower
14A-16A Room 1
14B-16B 2nd chamber
22 partition
25-27 1st-3rd distillation part
41 Feed nozzle
42 Side cut nozzle
81 reducer
82 Evaporator
83 Fully contractor
84, 94 Decanter
AR1, AR3, AR5 1st-3rd concentration part
AR2, AR4, AR6 1st to 3rd recovery unit

Claims (8)

(A) the tower body;
(B) a first condenser connected to the tower body and condensing at least a part of the vapor discharged from the tower body to be refluxed to the tower body as a first reflux liquid;
(C) a second condenser that condenses at least a part of the vapor discharged from the tower body to form a distillate;
(D) A distillation apparatus comprising: a separator for separating the distillate into layers, and refluxing the liquid constituting one layer to the tower body as a second reflux liquid. (A) the tower body;
(B) a partition that divides the tower body and forms a first chamber and a second chamber adjacent to each other;
(C) a stock solution is supplied via a feed nozzle, a distillation section having a concentration section formed above the feed nozzle, and a recovery section formed below the feed nozzle;
(D) another distillation unit that is connected to the distillation unit and includes a concentration unit formed above and a recovery unit formed below;
(E) a first condenser connected to the tower body and condensing at least a part of the vapor discharged from the tower body and refluxing the tower body as a first reflux liquid;
(F) a second condenser that condenses at least a part of the vapor discharged from the tower body into a distillate;
(G) A distillation apparatus comprising a separator for separating the distillate into layers and refluxing the liquid constituting one layer to the tower body as a second reflux liquid. (A) the tower body;
(B) a partition that divides the tower body and forms a first chamber and a second chamber adjacent to each other;
(C) A first distillation provided with a first concentrating part that is supplied with a stock solution via a feed nozzle and formed above the feed nozzle, and a first recovery part that is formed below the feed nozzle. And
(D) connected to the upper end of the first distillation unit, the second concentration unit formed above the upper end, and formed below the upper end, and the first concentration through a partition. A second distillation section comprising a second recovery section adjacent to the section;
(E) a third concentrating unit connected to the lower end of the first distillation unit, formed above the lower end and adjacent to the first recovery unit via a partition; and below the lower end A third distillation section provided with a third recovery section formed in
(F) a first condenser connected to the tower body, condensing at least a part of the vapor discharged from the tower body, and refluxing the tower body as a first reflux liquid;
(G) a second condenser that condenses at least a part of the steam discharged from the tower body to form a distillate;
(H) a separator for separating the distillate into layers and refluxing the liquid constituting one layer to the tower body as a second reflux liquid;
(I) A distillation apparatus having a side cut nozzle that is disposed on the tower side and discharges the liquid discharged on the tower side as a side cut liquid. (A) In the first condenser, cooling with a first cooling medium is performed;
(B) The distillation apparatus according to claim 1, wherein the second condenser is cooled by a second cooling medium having a temperature lower than that of the first cooling medium. (A) an azeotropic agent is added,
(B) The distillation apparatus according to claim 1, wherein in the separator, the azeotropic agent constitutes the one layer and is circulated. The distillation apparatus according to any one of claims 1 to 3, wherein the distillate is formed by condensing the remaining steam discharged from the first condenser. (A) a first refluxing step of condensing at least a part of the vapor discharged from the tower body and refluxing it to the tower body as a first reflux liquid;
(B) At least a part of the vapor discharged from the tower main body is condensed into a distillate, the distillate is separated into layers, and the liquid constituting one layer is used as a second reflux liquid in the tower main body. And a second refluxing step for refluxing. (A) a first refluxing step of condensing at least a part of the steam discharged from the tower body and refluxing it to the tower body as a first reflux liquid;
(B) condensing the vapor that was not condensed in the first refluxing step into a distillate,
(C) A distillation method characterized by comprising a second refluxing step of separating the distillate into layers and refluxing the liquid constituting one layer to the tower body as a second refluxing liquid.

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