JP2001079302A - Distillation device and distillation method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To concentrate side-cut liquid to enhance the purity of bottom product liquid and a recovery yield of distillate by discharging the distillate, the side-cut liquid and the bottom product liquid by respective discharging means after supplying a raw material liquid to a distillation part from a feeding nozzle and at the same time changing the discharging position of the side-cut liquid. SOLUTION: A bonded type distillation column 10 is constituted of many sections 11-19. A column main body has each section 14-16 combination which is divided into plural chambers 14A-16A, 14B-16B by inner partition walls 22 of the section 14-16 combination and has also each section 11-13 and 17-19 combinations to form many distillation parts 25-I7. A feeding nozzle 41 is disposed at a chamber 15a in the section 15 of a central part and many side-cut nozzles 53-55 are disposed in a recovery part AR4 consisting of a chamber 14B in a multistage shape. A steam outlet 43 and a reflux inlet 44 are disposed in the section 11 disposed at the top part of the column main body. Further, a bottom product liquid outlet 45 and a steam inlet 46 are disposed in the section 19 disposed in the bottom part of the column main body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a distillation apparatus and a distillation method thereof.

[0002]

2. Description of the Related Art Conventionally, when separating each component from a stock solution containing a plurality of components by distillation, a plurality of distillation columns are combined.

FIG. 2 is a conceptual diagram of a conventional distillation apparatus having two distillation columns.

In the figure, reference numeral 111 denotes a first distillation column, 11
2 is a second distillation column, 201 and 203 are evaporators, 202,
204 is a condenser. For example, if it is desired to distill a stock solution M containing three components A to C,
Assuming that the boiling point of the component B is lower than that of the component C,
Is separated from the component A and the components B and C in the distillation column 111, and the component B and the component C are separated in the second distillation column 112.

[0005] However, in the above-mentioned distillation apparatus, it is necessary to repeat heating and cooling in the first and second distillation columns 111 and 112.
The condensers 202 and 204, pumps, instrumentation, and the like (not shown) are required, so that the occupied area increases, and the amount of use of the utility and energy consumption increase. Therefore, the cost of the distillation apparatus increases.

[0006] Therefore, using a single distillation column, each component A
There is provided a distillation apparatus adapted to separate .about.C.

FIG. 3 is a conceptual diagram of a conventional distillation apparatus having one distillation column.

In the figure, 113 is a distillation column, 205 is an evaporator, and 206 is a condenser. For example, three components A to
When the stock solution M containing C is supplied to the distillation column 113, the component A is taken out as a distillate from the top of the column, the component C is taken out as a bottom product from the bottom, and the component B is taken as a side cut solution from the side of the column.

In this case, each of the components A
To C can be separated, so that only one evaporator 205, one condenser 206, one pump, one instrument, and the like are required. Therefore, the occupied area can be reduced, and the usage amount and energy consumption of the utility can be reduced. As a result, the cost of the distillation apparatus can be reduced.

[0010]

However, in the above-mentioned conventional distillation apparatus, since three components A to C are taken out from one distillation column 113, for example, it is attempted to take out component B as a product. At this time, unnecessary components A (low-boiling substances) and component C (high-boiling substances) flowing through the distillation column 113 are mixed into the product. When the distillation apparatus is operated with priority given to the purity of the product, the recovery rate of the product is reduced. When the distillation apparatus is operated with priority given to the recovery rate of the product, the purity of the product is reduced.

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 increasing the purity and recovery of a product.

[0012]

For this purpose, in the distillation apparatus of the present invention, there is provided a column main body, and a partition which divides the inside of the column main body and forms a first chamber and a second chamber adjacent to each other,
A first distillation section having an enrichment section at the top and a recovery section at the bottom, and at least a portion disposed adjacent to the top of the column body, an enrichment section at the top, and a recovery section at the bottom A second distillation section, a third distillation section at least partially disposed adjacent to the bottom of the column main body, having a concentrating section above, and a collecting section below, A feed nozzle for supplying the undiluted solution to the distillation section, a first discharge means disposed at the top of the column for discharging a distillate, and a second discharge means disposed on the side of the tower and discharging the side cut liquid And a third discharging means disposed at the bottom of the tower and discharging the bottoms.

[0013] The second discharge means includes a plurality of side cut nozzles arranged at different positions.

In another distillation apparatus of the present invention, a valve that can be opened and closed is connected to each of the side cut nozzles, and the valve is opened and closed according to the operating conditions.

[0015] In still another distillation apparatus of the present invention, the valve is opened and closed in accordance with the temperature inside the column body.

[0016] In still another distillation apparatus of the present invention, the partition may be disposed at the center in the main body of the column.
The cross-sectional area of the chamber is made equal to the cross-sectional area of the second chamber.

In still another distillation apparatus of the present invention, the partition is eccentric, and the sectional area of the first chamber is different from the sectional area of the second chamber.

In the distillation method of the distillation apparatus according to the present invention,
A column body divided by a middle partition and formed with a first chamber and a second chamber adjacent to each other, a concentrating section above, a first distillation section having a collecting section below, and at least a part of the column body. A second distillation section provided with an enrichment section above, a recovery section below, and at least a portion disposed adjacent to the bottom of the column body, The enrichment section is applied to a distillation apparatus having a third distillation section provided with a recovery section below.

Then, a stock solution is supplied to the first distillation section, a distillate is discharged at the top of the column, and at least one of a plurality of side cut nozzles arranged on the side of the column is selected. The side cut liquid is discharged from the selected side cut nozzle, and the bottom liquid is discharged at the bottom of the column.

[0020]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a conceptual diagram of a combined distillation column according to a first embodiment of the present invention, FIG. 4 is a sectional view of a main part of the combined distillation column according to the first embodiment of the present invention, and FIG. It is the schematic of the 2nd chamber of the 4th section in a 1st embodiment of the present invention.

In the figure, 10 is 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 1
4, a fifth section 15, a sixth section 16, a seventh section 17, an eighth section 18, and a ninth section 19.

The column body of the combined distillation column 10 has first chambers 14A to 16A formed by a flat partition 22 extending over the upper halves of the fourth section 14, the fifth section 15 and the sixth section 16. And the second room 1
4B to 16B, and the first chambers 14A to 16A and the second chambers 14B to 16B are adjacent to each other. Also,
The first distillation section 25 is provided by the first chambers 14A to 16A.
However, the second distillation section 26 is formed by the first section 11, the second section 12, the third section 13, and the second chamber 14B, and the second chamber 15B, 16B, the seventh section 17, the eighth section 18, and Third sections 27 are respectively formed by the nine sections 19.

The partition 22 may be formed of a heat insulating material, or the inside of the partition 22 may be evacuated.
The middle partition 22 can also have a heat insulating structure. In this case, between the first chamber 14A and the second chamber 14B, the first chamber 15A
Between the first chamber 16B and the first chamber 16A and the second chamber 16B.
Since the heat transfer to B can be reduced, the efficiency of distillation can be increased.

The fifth section 15 is disposed substantially at the center of the combined distillation column 10 in the height direction, and the feed nozzle 41 is disposed in the first chamber 15A. Also,
The first section 11 is provided at the top of the combined distillation column 10, and the first section 11 is provided with a vapor outlet 43 and a reflux liquid inlet 44 which are connected to a condenser (not shown). Further, the ninth column is attached to the bottom of the combined distillation column 10.
A section 19 is provided, and a bottoms outlet 45 and a steam inlet 46 are provided in the ninth section 19, respectively.
In addition, a distillation apparatus is configured by the combined distillation column 10, the condenser, and the like. The steam outlet 43 and the condenser constitute a first discharging means.

In the combined distillation column 10 having the above structure, a mixture containing the components A, B1, B2 and C is supplied to the feed nozzle 41 as a stock solution M, and the component A is taken out as a purified product. In this case, component A has a lower boiling point than component B1, component B1 (medium boiling component) has a lower boiling point than component B2 (high boiling component), and component B2 has a lower boiling point than component C.
Each of the components B1 and B2 is composed of multiple components containing a plurality of components.

In the first distillation section 25, the enrichment section AR1 is recovered by the first chamber 14A disposed above the feed nozzle 41, and recovered by the first chamber 16A disposed below the feed nozzle 41. The portions AR2 are respectively formed. Then, in the second distillation section 26, the enrichment section AR3 is formed by the second section 12 disposed above the upper end of the first distillation section 25 by the first section.
Below the upper end of the distillation section 25, the enrichment section AR
The collection sections AR4 are formed by the second chambers 14B disposed adjacent to the first chambers 1 and 2, respectively. Further, in the third distillation section 27, the enrichment section is connected to the lower end of the first distillation section 25, and the enrichment section is provided above the lower end by a second chamber 16B disposed adjacent to the recovery section AR2. AR5
However, the recovery sections AR6 are respectively formed by the eighth sections 18 disposed below the lower end of the first distillation section 25.

As described above, the upper end of the first distillation section 25 is located in the middle of the second distillation section 26 in the height direction, and the lower end of the first distillation section 25 is located in the height direction of the third distillation section 27. Are connected in the middle.

In the recovery section AR2, the stock solution M supplied from the feed nozzle 41 moves downward, and the vapors rich in the components A and B1 move upward, and the vapors rich in the components B2 and C move downward. A liquid is generated, and a liquid rich in components B2 and C is supplied to the third distillation section 27 from the lower end of the first distillation section 25.

Next, the liquid rich in the components B2 and C is heated in the third distillation section 27 to become a vapor rich in the components B2 and C. The vapor rich in the components B2 and C is While being moved upward in the recovery part AR2, the raw material M comes into contact with the stock solution M, and generates a vapor rich in the components A and B1 from the stock solution M.

Subsequently, the vapor rich in the components A and B1 is
The first distillation section 25 moves upward in the concentration section AR1.
Is supplied to the second distillation section 26 from the upper end of the second distillation section 26. Further, the vapor enriched in the components A and B1 is cooled and condensed in the second distillation section 26 to become a liquid enriched in the components A and B1. Then, a part of the liquid rich in the components A and B1 is returned to the concentrating unit AR1, and is brought into contact with the vapor rich in the components A and B1 that can be moved upward in the concentrating unit AR1. In this way, vapor rich in components A and B1 is supplied from the upper end of the first distillation section 25 to the second distillation section 26.

In the second distillation section 26, the vapor enriched in the component A in the upper part is changed to the component A in the lower part.
A liquid rich in B1 is generated. Then, the vapor rich in the component A moves upward in the concentrating section AR3, is discharged from the vapor outlet 43, is sent to the condenser, and is condensed by the condenser, and is condensed by the liquid rich in the component A. And discharged as a distillate. Further, the liquid rich in components A and B1 moves downward in the recovery section AR4.

In order to improve the efficiency of the purification of the component A, a part of the liquid rich in the component A is supplied to the reflux liquid inlet 4
4 is returned to the enrichment section AR3 and is brought into contact with vapors rich in the components A and B1 which can be moved upward in the enrichment section AR3.

On the other hand, in the third distillation section 27, the component B
Some of the vapors rich in 1, B2, and C move upward in the enrichment section AR5 and the recovery section AR4, and come into contact with the liquids rich in the components A and B1 from the enrichment section AR3 in the recovery section AR4. , Resulting in a liquid rich in components A and B1. In this way, the liquids rich in the components A and B1 obtained in the collecting part AR4 are provided in the collecting part AR4 in a plurality, in the present embodiment, three side cut nozzles 53 to
One of the liquids 55 is discharged as a first side cut liquid.

Further, the vapor rich in the components B2 and C is supplied to the component B from the second distillation section 26 at the upper end of the recovery section AR6.
2. Contact with a liquid rich in C to become a liquid rich in components B2 and C. Thus, the enrichment section AR5 and the recovery section AR
6 and the liquid rich in components B2 and C obtained between the side cut nozzle 5 and the side cut nozzle 5
Exhausted from 6.

Further, in the recovery section AR6, the liquid rich in the components B2 and C moves downward, and the vapor rich in the components B2 and C moves upward, and the vapor of the component C decreases as it goes downward.
Respectively to generate liquids rich in water. Therefore, the liquid rich in the component C is discharged from the bottom outlet 45 as bottoms. The third outlet means is constituted by the bottom outlet 45.

When the component C is water (H ₂ O), the liquid rich in the component C discharged from the bottom outlet 45 is sent to a wastewater treatment device (not shown) to be subjected to wastewater treatment. You. In this case, the component B in the third distillation section 27
2. In heating a liquid rich in C, components B2 and C
When the liquid rich in water is brought into direct contact with high-temperature steam (H ₂ O), the thermal efficiency can be increased. Therefore, a steam injection nozzle 51 is provided near the lower end in the ninth section 19, and steam is supplied from a steam supply source (not shown) to the steam injection nozzle 51 via the steam inlet 46. Therefore, the steam injection nozzle 51
The water vapor discharged from is heated and condensed while heating the liquid rich in the components B2 and C, and is discharged from the bottom outlet 45 together with the component C.

When the component C is not water, the steam injection nozzle 51 is not provided in the ninth section 19.
In this case, a part of the component C-rich liquid discharged from the bottom outlet 45 is sent to an evaporator (not shown), and is heated by the evaporator to be a component C-rich vapor. The vapor rich in the component C is supplied to the ninth section 19, and comes into contact with the liquid rich in the components B2 and C while being moved upward in the ninth section 19 and the recovery part AR6,
A vapor rich in components B2 and C is generated from the liquid rich in components B2 and C. The evaporator forms a steam supply source.

As described above, the vapor rich in the component A is discharged from the vapor outlet 43 and condensed into a distillate,
The liquid rich in components A and B1 is supplied to the side cut nozzle 53
To 55, a liquid rich in components B2 and C is discharged as a second sidecut liquid from the sidecut nozzle 56, and a liquid rich in component C is discharged from the sidecut nozzle 56. Is discharged from the bottom outlet 45 as bottoms. Then, the distillate becomes a product, the first side cut liquid is sent to a not-shown recovery device, and the component A contained in the first side cut liquid in the next step
Is collected. In addition, the second side cut liquid contains the component C
Is contained as a main component, but because it contains components B1 and B2, it is sent to an incinerator (not shown) as waste liquid and incinerated. When the component C is water, the bottom liquid is sent to the wastewater treatment device, where the wastewater treatment is performed.

In the present embodiment, the enrichment section AR3
A regular packing consisting of one node is used as the packing to be filled in the packing section, and a number of sleeve-like packings are used as the packing to be filled in the enrichment sections AR1, AR5 and the recovery sections AR2, AR4, AR6. An irregular packing formed by randomly packing pole rings, Raschig rings, etc., is used. Random packings can be easily replaced if they are degraded by corrosive liquids or vapors. It should be noted that an irregular packing can be used instead of the ordered packing, or an ordered packing can be used instead of the irregular packing. It is also possible to use a filling consisting of a plurality of nodes.

As described above, since the stock solution M can be separated into the components A, B1, B2, and C without using a plurality of distillation columns, a condenser, an evaporator, a pump, an instrument, and the like can be used. There is no need to arrange a large number. Therefore, not only the occupied area can be reduced, but also the usage amount and energy consumption of the utility can be reduced, so that the cost of the distillation apparatus can be reduced.

A riser tray 65 is provided in the third section 13, and a riser tray 66 is provided below the feed nozzle 41 in the first chamber 15 A of the fifth section 15.
Riser tray 6 in second chamber 15B of fifth section 15
7, a riser tray 68 is provided in the seventh section 17. Each of the riser trays 65 to 68 constitutes a chimney hat type collector, which collects liquid and allows vapor to pass therethrough.

The liquid collected by the riser tray 65 is distributed to the first chamber 14A and the second chamber 14B of the fourth section 14, and the first side cut liquid is supplied to the side cut nozzles 53-55. From one of them,
Since the second side cut liquid is discharged from the side cut nozzle 56, the amount of the liquid distributed to the first chamber 14A needs to be larger than the amount of the liquid distributed to the second chamber 14B.

Therefore, the middle partition 22 is eccentric to the side where the feed nozzle 41 is not provided, that is, to the second chambers 14B to 16B. And the first chambers 14A-1
6A and S2 of the second chambers 14B to 16B.
Γ1 γ1 = S1 / S2 is set to a smaller value as the component composition of the components B1 and B2 in the stock solution M is larger, and is set to a larger value as the component composition of the components B1 and B2 is smaller.

As described above, by making the sectional areas S1 and S2 different, the amounts of steam and liquid flowing in the first chambers 14A to 16A and the amounts of steam and liquid flowing in the second chambers 14B to 16B are reduced. Even if different, the first chambers 14A to 16A and the second chambers 14B to 16B can be used effectively. Therefore, the heat load applied to the steam supply source can be reduced, so that the energy consumption for distillation can be reduced. The first chambers 14A to 16A
A, the amount of the vapor and the liquid flowing in the inside A, and the second chamber 14B-
Depending on the amounts of the vapor and the liquid flowing through the inside of the tower 16B, the partition 22 is disposed in the center of the tower main body so that the cross-sectional areas S1 and S2 are equal, or the cross-sectional area S1 is eccentric to the first chambers 14A to 16A. Can be made smaller than the cross-sectional area S2.

Next, the second chamber 14B of the fourth section 14
Will be described.

In FIG. 5, reference numeral 60 denotes the fourth section 14.
The grid 61 disposed at the lower end of the second chamber 14B is a grid that is disposed at three places in the second chamber 14B and divides the interior of the second chamber 14B into four regions. Is supported. Reference numeral 62 denotes a riser tray disposed immediately below each grid 61. The riser tray 62 receives the liquid moving downward in the second chamber 14B and distributes the liquid to the lower packing 63, 2nd room 1
Pass the vapor moving upward in 4B. Therefore, each riser tray 62 constitutes a chimney hat type collector.

In the riser tray 62, the front ends of the side cut nozzles 53 to 55 are opened. The tips of the side cut nozzles 53 to 55 are disposed so as to slightly protrude from the bottom surface of each riser tray 62, and the liquids rich in the components A and B1 that have fallen on the riser tray 62 are:
The liquid accumulates on the riser tray 62 and is discharged from the side cut nozzles 53 to 55.

In the combined distillation column 10 having the above-mentioned structure, since the component B1 is a multi-component, the concentration stage of the component B1, that is, the optimal position for taking out the first side cut liquid is determined by the combined distillation column. It depends on the 10 operating conditions, for example, the component composition of each component contained in component B1. Therefore, one of the side cut nozzles 53 to 55 is selected according to the component composition of the component B1, and the first side cut liquid is discharged from the selected side cut nozzle.

For this purpose, the side cut nozzle 53
Each of the valves 55 to 55 is provided with a valve (not shown) so that each valve can be opened and closed manually or automatically by a signal from a control device (not shown). Then, a temperature sensor (not shown) as operating condition detecting means is disposed near the feed nozzle 41 in the tower main body, and the temperature inside the tower main body is detected by the temperature sensor. Since the temperature inside the tower body changes according to the component composition of the component B1, the component composition of the component B1 can be detected by detecting the temperature inside the tower body.
When a storage tank (not shown) for storing the stock solution M supplied to the feed nozzle 41 is provided, the component composition of the stock solution M in the storage tank is detected by an analyzer (not shown) as operating condition detection means, The valve can be opened and closed based on the detection result. The second discharge means is constituted by the side cut nozzles 53 to 55, a valve and the like.

As described above, the side cut nozzles 53 to 5
5 is selected and the position for discharging the first sidecut liquid is optimized, so that the first sidecut liquid is concentrated and the amount discharged is reduced. Therefore, not only can the purity of the distillate be increased, but also the amount of the distillate, that is, the fraction can be increased, and the recovery rate of the distillate can be increased.

The first side cut solution contains the component B1
Since the component A is contained in addition to the above, the component A is recovered from the first side cut liquid in the recovery device, but the recovered amount of the component A is reduced by the small amount of the first side cut liquid. Can be reduced. Therefore,
Since the energy required for recovering component A in the recovery device can be reduced, the cost of component A can be reduced.

In this embodiment, the side cut nozzles 53 to 55 are arranged in the collecting section AR4. However, the side cut nozzles 53 to 55 are arranged in the collecting section AR4 and the enriching section AR5. It can also be arranged in. Further, in the present embodiment, one of the side cut nozzles 53 to 55 is selected, but two or more side cut nozzles can be selected.

Next, a second embodiment of the present invention will be described. In addition, about what has the same structure as 1st Embodiment, the description is abbreviate | omitted by attaching the same code | symbol.

FIG. 6 is a schematic view of a main part of a combined distillation column according to a second embodiment of the present invention.

In the drawing, reference numeral 71 denotes a grid provided at the lower end of the fourth section 14, and 72 denotes a grid in the second chamber 14B.
This is a grid that is disposed at a location and divides the inside of the second chamber 14 </ b> B into two regions, and the filling 63 is supported by the grids 71 and 72. Immediately below the grid 71, riser trays 76 and 77 are provided.
6 receives the undiluted solution M supplied to the feed nozzle 41 and distributes the concentrate to the filling 63 in the first chamber 16A of the sixth section 16 and the first chamber 15A of the fifth section 15.
Passes steam moving upward through the inside of the riser tray 7
7 receives the liquid moving downward in the second chamber 15B, distributes the liquid to the upper packing 63 in the second chamber 16B, and passes the vapor moving upward in the second chamber 16B. Immediately below the grid 72, a riser tray 78 is provided.
4B, receives the liquid moving downward and distributes the liquid to the lower packing 63 in the second chamber 14B.
Pass the vapor moving upward in 4B.

Reference numeral 73 denotes a grid provided at the lower end of the sixth section 16, and 74 denotes a grid provided at one location in the second chamber 16B to divide the inside of the second chamber 16B into two regions. And the filling 63 by each grid 73,74
Is supported. Immediately below the grid 73, a riser tray 68 is provided. The riser tray 68 receives the liquid moving downward in the seventh section 17, distributes the liquid to the filler 63 in the eighth section 18, and Seventh
The steam moving upward in the section 17 is passed.
Immediately below the grid 74, a riser tray 82 is provided, and the riser tray 82 is disposed in the second chamber 16B.
Receiving the liquid moving downward in the inside and distributing it to the lower packing 63 in the second chamber 16B,
Pass the steam moving upwards in the interior.

The riser trays 77, 78, 8
2, the front ends of the side cut nozzles 53 to 55 are opened. The liquids rich in the components A and B1 that have fallen into the riser trays 77, 78 and 82
8 and 82 and are discharged from the side cut nozzles 53 to 55. Each of the packings 63 is made of an irregular packing.

Then, one of the side cut nozzles 53 to 55 is selected according to the component composition of the component B1, and
In order to discharge the first side cut liquid from the selected side cut nozzle, the side cut nozzles 53 to 5 are used.
5 are provided with valves V1 to V3.
To V3 can be opened and closed manually or automatically by a signal from a control device (not shown).

As described above, the side cut nozzle 53 is placed in the second chamber 14B and the side cut nozzle 54 is placed in the second chamber 15B.
In addition, the side cut nozzle 55 can be disposed in the second chamber 16B.

Next, a third embodiment of the present invention will be described. In addition, about what has the same structure as 1st Embodiment, the description is abbreviate | omitted by attaching the same code | symbol.

FIG. 7 is a schematic view of a main part of a combined distillation column according to a third embodiment of the present invention.

In the drawing, reference numeral 71 denotes a grid provided at the lower end of the fourth section 14, and 72 denotes a grid in the second chamber 14B.
This is a grid that is disposed at a location and divides the inside of the second chamber 14 </ b> B into two regions, and the filling 63 is supported by the grids 71 and 72. Grid 7 in the first room 15A
1, a collector lamina 176, a collector box 351, and a distributor 352 are provided. The collector lamina 176 receives the liquid from the first chamber 14 </ b> A and collects the collected liquid in the collector box 351. Receiving the collected liquid and the undiluted liquid M supplied to the feed nozzle 41, the liquid is distributed to the packing 63 in the first chamber 16A, and the first chamber 1
The vapor moving upward in 5A is passed. Also, the second
Immediately below the grid 71 in the chamber 15B, a collector lamina 177 is provided.
The liquid moving downward in the chamber 15B is received and collected in the collector box 353, and the distributor 354 receives the liquid collected in the collector box 353 and distributes the liquid to the upper packing 63 in the second chamber 16B.
The vapor moving upward in the second chamber 15B is passed.

A collector lamina 178 is provided directly below the grid 72, and the collector lamina 178 is provided.
Receives the liquid moving downward in the second chamber 14B and collects the collected liquid in the collector box 355.
Receives the liquid collected in the collector box 355, distributes the liquid to the lower packing 63 in the second chamber 14B, and passes vapor moving upward in the second chamber 14B.

Reference numeral 73 denotes a grid provided at the lower end of the sixth section 16, and 74 denotes a grid provided at one location in the second chamber 16B to divide the inside of the second chamber 16B into two regions. And the filling 63 by each grid 73,74
Is supported. Immediately below the grid 73, a collector lamina 168 is disposed. The collector lamina 168 receives the liquid moving downward in the seventh section 17 and collects the collected liquid in a collector box 357.
Receives the liquid collected in the collector box 357, distributes the liquid to the packing 63 in the eighth section 18, and allows the vapor moving upward in the seventh section 17 to pass therethrough. A collector lamina 182 is provided directly below the grid 74.
Receives the liquid moving downward in the second chamber 16B and collects the collected liquid in the collector box 359.
Receives the liquid collected in the collector box 359 and distributes the liquid to the packing 63 immediately below, and the second chamber 16
The vapor moving upward in B is passed.

The collector boxes 353, 35
The ends of side cut nozzles 53 to 55 are opened at 5, 359. Collector box 353, 355, 3
The liquid rich in components A and B1 collected in 59 is discharged from the side cut nozzles 53 to 55. Each of the packings 63 is composed of a regular packing.

Then, one of the side cut nozzles 53 to 55 is selected according to the component composition of the component B1, and
In order to discharge the first side cut liquid from the selected side cut nozzle, the side cut nozzles 53 to 5 are used.
5 are provided with valves V1 to V3.
To V3 can be opened and closed manually or automatically by a signal from a control device (not shown).

As described above, the side cut nozzle 53 is placed in the second chamber 14B and the side cut nozzle 54 is placed in the second chamber 15B.
In addition, the side cut nozzle 55 can be disposed in the second chamber 16B.

Next, a fourth embodiment of the present invention will be described. In addition, about what has the same structure as 1st Embodiment, the description is abbreviate | omitted by attaching the same code | symbol.

FIG. 8 is a schematic view of a combined distillation column according to a fourth embodiment of the present invention, FIG. 9 is a plan view of a side cut nozzle according to the fourth embodiment of the present invention, and FIG. It is sectional drawing of the side cut nozzle in 4th Embodiment. 9 and 10, since the side cut nozzles 53 to 55 have the same structure, only the side cut nozzle 53 will be described.

In this case, the recovery section AR of the second distillation section 26
4 and the enrichment section AR5 of the third distillation section 27 are integrated,
An irregular packing is used as the packing to be filled in the recovery section AR4 and the concentration section AR5.

The recovery section AR4 and the concentration section AR
The plate-shaped side cut nozzles 53 to 55 are disposed inclining in 5, and the liquids rich in the components A and B1 dropped onto the side cut nozzles 53 to 55 are discharged as the first side cut liquid. The side cut nozzle 53 ~
55 includes a plate portion 94 having a semicircular groove 90 extending in the axial direction at the center, a flange portion 91 formed on both edges of the plate portion 94, and a net 93 covering the groove 90. It is inclined so that it becomes higher as it is closer to the center of the tower body.

Therefore, when the liquids rich in the components A and B1 drop onto the side cut nozzles 53 to 55,
It is collected by the plate portion 94 and flows along the groove 90. In addition, 81 is a condenser.

[0074]

EXAMPLE 1 FIG. 11 is a conceptual diagram of a distillation apparatus of a reference example having one distillation column having no partition, and FIG.
FIG. 4 is a view showing a distillation result by a distillation apparatus of a reference example.

In the drawing, reference numeral 313 denotes a distillation column, 306 denotes a condenser, and 351 denotes a steam injection nozzle. Steam is supplied to the steam injection nozzle 351 from a steam supply source (not shown).

Stock solution M containing components A, B1, B2 and C
Is supplied to the distillation column 313, a liquid rich in the component A from the top of the column as a distillate, and a liquid rich in the components A and B1, and a liquid rich in the components B2 and C from the side of the column, 2
, A liquid rich in component C is taken out from the bottom of the column as a bottom product.

The distillation conditions in the distillation column 313 were set as follows.

Component A: Acetaldehyde Component B1: Medium boiling point component (dichloromethane, chloroform, chloroacetaldehyde, etc.) Component B2: High boiling point component (dichloroacetaldehyde, acetic acid, etc.) Component C: Water Component composition of stock solution M: Component A: 77 0.000 [wt%] Component B1: 0.59 [wt%] Component B2: 1.62 [wt%] Component C: 20.79 [wt%] Theoretical plate number: 30 plates Stock solution supply amount: 10400 [kg / h] Reflux ratio: 1.4 Head pressure: 1.20 [kg / cm ² G] (219 [kP
aA]) Top temperature: 43 [° C.] Heating source: A method in which steam is directly blown into the bottom of the tower Column diameter Concentrating unit: ID 1800 (shelf-stage method: perforated tower) Recovery unit: ID 1550 (irregular packing: pole) Ring) As a result, as shown in FIG.
[Wt%] could be purified. Example 1 FIG. 13 is a view showing the result of distillation by a distillation apparatus according to the first embodiment of the present invention.

The distillation conditions in the combined distillation column 10 (FIG. 1) were set as follows.

Component A: Acetaldehyde Component B1: Medium boiling point component (dichloromethane, chloroform, chloroacetaldehyde, etc.) Component B2: High boiling point component (dichloroacetaldehyde, acetic acid, etc.) Component C: Water Component composition of stock solution M: Component A: 77 0.000 [wt%] Component B1: 0.59 [wt%] Component B2: 1.62 [wt%] Component C: 20.79 [wt%] Theoretical plate number: 30 plates Stock solution supply amount: 10400 [kg / h] Reflux ratio: 1.4 Head pressure: 1.20 [kg / cm ² G] (219 [kP
aA]) Top temperature: 43 [° C.] Heating source: A method in which steam is directly blown into the bottom of the tower Column diameter Concentrator AR3: ID 1650 (regular packing):
Merapak 250Y (manufactured by Sumitomo Heavy Industries, Ltd.) Concentration units AR1, AR5, collection units AR2, AR4: ID
1650 (irregular packing): pole ring Recovery unit AR6: ID 1550 (irregular packing: pole ring) Cross-sectional area ratio γ1: 70/30 Liquid distribution ratio γ2: feed side / side cut side = 62/3
8 ≒ 1.63158 As a result, as shown in FIG.
[Wt%] could be purified.

Since the discharge amount of the first and second side cut liquids is small, the position where the partition 22 is disposed is eccentric from the center of the tower main body, and the first chambers 14A to 16A and the second chamber 14
By making the amounts of the vapor and the liquid flowing through B to 16B different, the column specifications of the combined distillation column 10 can be made equal to those of the conventional type.

In this case, the component composition of the component A in the stock solution M is pA [wt%], and the component composition of the component B1 is pB1
[Wt%], and the component composition of component B2 is pB2 [wt
%] And the component composition of the component C is pC [wt%], the component compositions pA, pB1, pB2, and pC are pA>pC> pB1, pB2. ~ 1
An eccentric combined distillation column 10 eccentric to the 6B side is used.

Note that the component compositions pA, pB1, pB2, p
When C is pB1, pB2> pA, pC, the middle partition 22 is disposed at the center.

A comparison between the distillation apparatus of Example 1 and the distillation apparatus of Reference Example 1 shows that the mass flow rate of steam was 2200
[Kg / h] and equalizing the heating energy,
The mass flow rate of the distillate was 78 in the case of the distillation apparatus of Reference Example 1.
60 kg / h, whereas in the case of the distillation apparatus of Example 1, it is 7895 kg / h, and 35 kg / h.
h) It is possible to increase production.

Therefore, it is possible to obtain about 35 [kg / h] × 8000 [h] = 280 [t / y] more of the component A annually.

Further, the amount of water vapor was reduced, and
[Kg / h] The amount of water vapor required for increasing the production, that is, the product basic unit can be reduced. Since the product basic unit can be represented by [amount of steam] × [increase in the amount of component A] / [amount of component A in the distillation apparatus of Reference Example 1], 2200 [kg / h] × 35 [kg] / H] / 7860
[Kg / h] ≒ 9.8 [kg / h].

The mass flow rate of the first side cut liquid was 200 [kg / h] in the case of the distillation apparatus of Reference Example 1, whereas it was 165 in the case of the distillation apparatus of Example 1.
[Kg / h], which can be reduced by 35 [kg / h].

Accordingly, the amount of the first side cut liquid can be reduced by 35 [kg / h] × 8000 [h] = 280 [t / y] annually, and the component A in the next step can be reduced.
Can be reduced. As a result, the amount of steam for heating used in the next step in the recovery device can be reduced, and the unit consumption of the product can be reduced. The product basic unit is (amount of steam for heating) ×
160 [kg / h] × 35 [kg / h] /, since it can be expressed by [the amount of the first side cut liquid reduced] / [the amount of the first side cut liquid in the distillation apparatus of Reference Example 1]. 200 kg
/ H] = 28 [kg / h].

In this case, the combined distillation column 10 is used to purify acetaldehyde by distillation. Acetaldehyde is provided at the top of the column, and dichloromethane, chloroform, chloroacetaldehyde, etc., and dichloroacetaldehyde, acetic acid, etc. are provided at the top of the column. Water can be obtained at the bottom, respectively, but other substances can be purified or condensed by distillation.

Then, when purifying high-grade benzene,
Inert gas as an exhaust gas at the top of the tower, benzene (product) as a first sidecut liquid on the side of the tower near the top, and toluene as a second sidecut liquid on the side of the tower near the bottom of the tower However, a small amount of heavy oil is respectively obtained at the bottom of the column.

When purifying vinyl acetate, a light fraction and vinyl acetate are obtained at the top of the column, purified vinyl acetate (product) as a side cut liquid is obtained at the side of the column, and a residue is obtained at the bottom of the column. In the next step, purified vinyl acetate is obtained from the light components and vinyl acetate by distillation.

When β-methylnaphthalene is concentrated, 95% of naphthalene (product)
However, the oil content as a side cut liquid on the tower side,
At the bottom of the column, methylnaphthalene residual oil is obtained. The oil is formed by concentrating β-methylnaphthalene, and in the next step, purified β-methylnaphthalene is purified from the oil.

Further, in the case of refining tall oil, first distilling tall oil (light fatty acid head) is provided at the top of the tower, and purified fatty acids (fatty acids having a low rosin content and extremely high purity) as side cut liquids are provided on the tower side. In the bottom of the column, purified distilled tall oil is obtained. [Reference Example 2] As shown in FIG. 2, the distillation conditions in a conventional distillation apparatus having two first and second distillation columns 111 and 112 are as follows.
That is, the composition of the component B was varied and set as follows.

Component A: cyclohexane 84.85 [wt%] (case 1) 84.85 [wt%] (case 2) Component B: 2-hexanone 0.10 [wt%] (case 1) 0.05 [ wt%] (Case 2) 2-hexanol 0.05 [wt%] (Case 1) 0.10 [wt%] (Case 2) Component C1: cyclohexanone 12.00 [wt%] (Case 1) 12.00 [Wt%] (case 2) Component C2: cyclohexanol 3.00 [wt%] (case 1) 3.00 [wt%] (case 2) In addition, 1-hexanone, 3-hexanone, 1-
Hexanol and 3-hexanol may be present, but only 2-hexanone and 2-hexanol.

First column (first distillation column 111) Number of theoretical plates Concentration unit: 10 stages Recovery unit: 15 stages Raw material supply: 2000 [kg / h] Distillate: 1697.2 [kg / h] Reflux ratio : 1.0 overhead pressure: normal pressure overhead temperature: 80.8 [° C] second column (second distillation column 112) number of theoretical plates enrichment unit: 10 recovery unit: 15 stages undiluted solution supply amount: 302.8 [Kg / h] Distillate: 5.0 [kg / h] Reflux ratio: 500 overhead pressure: normal pressure overhead temperature: 116 [° C] (case 1) 118 [° C] (case 2) Heat energy : First column 300,000 [kcal / h] Second column 260000-268000 [kcal / h] Total 560000-568000 [kcal / h] As a result, component A could be purified at 99.99 [wt%]. .

In this case, the component A purified in the cyclohexane recovery step of this step is returned to the previous oxidation reaction step, and is reused as a raw material.

The component C1, which is a high-boiling component, is obtained by separating and purifying the component C2 in the next step to obtain a high-purity component C1.
1 is obtained as a product. At this time, it is important to concentrate and remove the component B which is an intermediate boiling component (impurity) in the cyclohexane recovery step. [Reference Example 3] FIG. 14 is a view showing the distillation result of Case 1 by the distillation apparatus of another reference example, and FIG. 15 is a view showing the distillation result of Case 2 by the distillation apparatus of another reference example.

The distillation conditions in a conventional distillation apparatus having one distillation column 113 as shown in FIG. 3 were changed by changing the component composition of stock solution M, that is, the composition of component B in cases 1 and 2. The settings were as follows.

Component A: cyclohexane 84.85 [wt%] (case 1) 84.85 [wt%] (case 2) Component B: 2-hexanone 0.10 [wt%] (case 1) 0.05 [ wt%] (Case 2) 2-hexanol 0.05 [wt%] (Case 1) 0.10 [wt%] (Case 2) Component C1: cyclohexanone 12.00 [wt%] (Case 1) 12.00 [Wt%] (case 2) Component C2: cyclohexanol 3.00 [wt%] (case 1) 3.00 [wt%] (case 2) In addition, 1-hexanone, 3-hexanone, 1-
Hexanol and 3-hexanol may be present, but only 2-hexanone and 2-hexanol.

Number of theoretical plates: 35 plates Reflux ratio: 2.0 Top pressure: normal pressure Top temperature: 80.7 ° C. Tower bottom temperature: 155.1 ° C. Heating energy amount: 444000 kcal / h Cross-sectional area ratio γ1: 100 / 73.6 Liquid distribution ratio γ2: feed side / side cut side = 55/100 = 0.55 As a result, as shown in FIGS. 14 and 15, 99.99 wt. %]. [Example 2] Fig. 16 is a view showing a result of distillation of case 1 by another distillation apparatus according to the first embodiment of the present invention, and Fig. 17 is a view showing another distillation apparatus according to the first embodiment of the present invention. FIG. 14 is a diagram showing a distillation result of Case 2.

The distillation conditions in the combined distillation column 10 (FIG. 1) were determined in cases 1 and 2 as follows:
The composition of Component B was varied and set as follows.

Component A: cyclohexane 84.85 [wt%] (case 1) 84.85 [wt%] (case 2) Component B: 2-hexanone 0.10 [wt%] (case 1) 0.05 [ wt%] (Case 2) 2-hexanol 0.05 [wt%] (Case 1) 0.10 [wt%] (Case 2) Component C1: cyclohexanone 12.00 [wt%] (Case 1) 12.00 [Wt%] (case 2) Component C2: cyclohexanol 3.00 [wt%] (case 1) 3.00 [wt%] (case 2) In addition, 1-hexanone, 3-hexanone, 1-
Hexanol and 3-hexanol may be present, but only 2-hexanone and 2-hexanol.

Number of theoretical plates: 35 plates Reflux ratio: 2.0 Top pressure: normal pressure Top temperature: 80.7 ° C. Tower temperature: 155.1 ° C. Heating energy: 444000 kcal / h Cross-sectional area ratio γ1: 100 / 73.6 Liquid distribution ratio γ2: feed side / side cut side = 55/100 = 0.55 As a result, as shown in FIGS. 16 and 17, 99.99 wt. %].

In this case, compared to the distillation apparatus of Reference Example 2,
The required amount of heating energy can be reduced. That is, 444000 / 560000-568000 = 79-7
8%, the heating energy is about 20%
6000 to 124000 [kcal / h]).

Further, as compared with the distillation apparatus of Reference Example 3, although the required amount of heating energy is the same, the concentration of the component B which is an intermediate boiling point component (impurity) can be increased. That is, in Reference Example 3, the concentration of the component B was 51.5 to 5
In contrast to 4.2 [wt%], in Example 2, the concentration of the component B is 57.7 to 58.8 [wt%]. Accordingly, the amount of the component B is reduced accordingly, and the component C2 can be sufficiently separated and purified in the next step. As a result, the purity of the component C1 can be increased. In addition, since there are few intermediate boiling components (impurities), separation of cyclohexanone and cyclohexanol is facilitated.

When the composition of the component B is changed from case 1 to case 2, the stage for extracting the side cut liquid, that is, the side cut stage (the recovery section AR4 and the concentration section AR5)
) Is switched. In this case, the side cut stage is switched down by one stage.

When component B is contained in component A discharged from the top of the column, component B is returned to the previous oxidation reaction step together with component A, and is reused as a raw material. As a result, the component B accumulates in the circulation system and deteriorates the oxidation reaction.

However, as shown in FIGS. 14 and 15, in the distillation apparatus of Reference Example 3, the concentration of the component B in the distillate was 100 to 104 [ppm]. As shown, in the distillation apparatus of Example 2, the concentration of the component B was 587 [ppb] to 1
[Ppm], which can be extremely low.

In the distillation apparatuses of Reference Example 3 and Example 2, when the component B was discharged from the bottom of the column, the component B was mixed into the component C1 in the next step, and the production of adipic acid was performed in the subsequent step. In the distillation apparatus of Reference Example 3, the concentration of the component B in the bottoms was 363 to 8
In contrast, the concentration of the component B in the distillation apparatus of Example 2 is 185 to 393 [ppm], which is 64 [ppm].

The present invention is not limited to the above embodiments, but can be variously modified based on the gist of the present invention, and they are not excluded from the scope of the present invention.

[0111]

As described above in detail, according to the present invention, in the distillation apparatus, the column main body and the first chamber and the second chamber adjacent to each other are formed by dividing the inside of the column main body. A partition, a first enrichment section having an enrichment section above and a recovery section below, at least a portion of which is disposed adjacent to the top of the column main body, and an enrichment section is recovered upward and a lower section is recovered A second distillation unit having at least a portion disposed adjacent to the bottom of the column body, a concentration unit at the top, and a third distillation unit at the bottom with a recovery unit; A feed nozzle for supplying the undiluted solution to the first distillation section, a first discharge means disposed at the top of the column for discharging the distillate, and a second discharge means disposed on the side of the column for discharging the side cut liquid And a third discharging means disposed at the bottom of the tower and discharging bottom liquid.

The second discharging means has a plurality of side cut nozzles arranged at different positions.

In this case, the undiluted solution is supplied from the feed nozzle to the first
, A distillate is discharged by the first discharging means, a side cut liquid is discharged by the second discharging means, and a bottom liquid is discharged by the third discharging means.

Since the second discharge means includes a plurality of side cut nozzles arranged at different positions, the side cut liquid is discharged by selecting one of the side cut nozzles. Position can be optimized.

Therefore, the side cut solution is concentrated,
Moreover, since the amount discharged is reduced, not only the purity of the bottom liquid can be increased, but also the fraction discharged by the first discharging means can be increased, and the recovery rate of the distillate can be reduced. Can be higher.

Further, when recovering a predetermined component contained in the side cut solution, the amount of the component to be recovered can be reduced by the smaller amount of the side cut solution. Therefore, the energy required to recover the components can be reduced, and the cost of the components can be reduced.

In another distillation apparatus of the present invention, a valve that can be opened and closed is connected to each of the side cut nozzles, and the valve is opened and closed according to the operating conditions.

In this case, one of the side cut nozzles can be selected according to the operating conditions.
The position for discharging the side cut liquid can be optimized.

In still another distillation apparatus of the present invention, the partition is eccentric, and the sectional area of the first chamber is different from the sectional area of the second chamber.

In this case, even if the amounts of the vapor and the liquid flowing in the first chamber are different from the amounts of the vapor and the liquid flowing in the second chamber, the first and second chambers can be effectively used. Therefore, the heat load applied to the steam supply source can be reduced, and the energy consumption for distillation can be reduced.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a combined distillation column according to a first embodiment of the present invention.

FIG. 2 is a conceptual diagram of a conventional distillation apparatus having two distillation columns.

FIG. 3 is a conceptual diagram of a conventional distillation apparatus having one distillation column.

FIG. 4 is a sectional view of a main part of the combined distillation column according to the first embodiment of the present invention.

FIG. 5 is a schematic view of a second chamber of a fourth section according to the first embodiment of the present invention.

FIG. 6 is a schematic diagram of a main part of a combined distillation column according to a second embodiment of the present invention.

FIG. 7 is a schematic diagram of a main part of a combined distillation column according to a third embodiment of the present invention.

FIG. 8 is a schematic diagram of a combined distillation column according to a fourth embodiment of the present invention.

FIG. 9 is a plan view of a side cut nozzle according to a fourth embodiment of the present invention.

FIG. 10 is a sectional view of a side cut nozzle according to a fourth embodiment of the present invention.

FIG. 11 is a conceptual diagram of a distillation apparatus of a reference example including one distillation column having no partition.

FIG. 12 is a diagram showing a distillation result by a distillation apparatus of a reference example.

FIG. 13 is a diagram showing a distillation result by the distillation apparatus according to the first embodiment of the present invention.

FIG. 14 is a view showing a distillation result of Case 1 by a distillation apparatus of another reference example.

FIG. 15 is a diagram showing a distillation result of Case 2 by a distillation apparatus of another reference example.

FIG. 16 is a diagram showing a result of distillation of case 1 by another distillation apparatus according to the first embodiment of the present invention.

FIG. 17 is a diagram showing a result of distillation of case 2 by another distillation apparatus according to the first embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Combined distillation tower 14A-16A 1st chamber 14B-16B 2nd chamber 22 Partition 25-27 1st-3rd distillation part 41 Feed nozzle 43 Steam outlet 45 Can discharge outlet 53-55 Side cut nozzle 81 Condensation Vessel AR1, AR3, AR5 Concentration unit AR2, AR4, AR6 Collection unit V1-V3 Valve

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Katsunori Tamura 2-1-1 Tanidocho, Tanashi-shi, Tokyo Sumitomo Heavy Industries, Ltd. Inside Tanashi Factory (72) Inventor Yoichi Harada 2-1-1 Tanitocho, Tanashi-shi, Tokyo No. 1 Sumitomo Heavy Industries, Ltd. Tanashi Factory F-term (reference) 4D076 AA12 AA13 AA16 AA22 AA23 AA24 BB04 BB05 BB27 CA11 CA12 CB12 CC12 CC24 DA14 DA25 EA03X EA03Z EA04X EA04Z EA12Z EA17 EA16 EA16 EA16 EA16 EA16 EA16

Claims (6)

[Claims] 1. A (a) tower main body, (b) a partition that divides the inside of the tower main body and forms a first chamber and a second chamber adjacent to each other, (c) an enrichment section above, A first distillation section having a recovery section, and (d) a second distillation section having at least a part thereof disposed adjacent to the top of the column main body, having an enrichment section above and a recovery section below. A distillation section, (e) a third distillation section, at least a portion of which is disposed adjacent to the bottom of the column main body, an enrichment section above and a recovery section below, and (f) the third distillation section. A feed nozzle for supplying an undiluted solution to one distillation section;
(G) a first discharge means disposed at the top of the tower to discharge a distillate; (h) a second discharge means disposed at the side of the tower to discharge a side cut liquid; A third discharge means disposed at the bottom of the tower and discharging bottom liquid; and (j) the second discharge means comprises a plurality of side cut nozzles disposed at different positions. A distillation apparatus, comprising: 2. The distillation apparatus according to claim 1, wherein (a) a valve that can be opened and closed is connected to each of the side cut nozzles, and (b) the valve is opened and closed according to operating conditions. 3. The distillation apparatus according to claim 2, wherein the valve is opened and closed according to the temperature inside the tower body. 4. The distillation apparatus according to claim 1, wherein the partition is disposed in the center of the tower main body, and a sectional area of the first chamber is equal to a sectional area of the second chamber. 5. The distillation apparatus according to claim 1, wherein the partition is eccentric, and a sectional area of the first chamber is different from a sectional area of the second chamber. 6. A column body divided by a middle partition and formed with a first chamber and a second chamber adjacent to each other, a first distillation section provided with an enrichment section above and a recovery section below, at least a part of the first distillation section. Is disposed adjacent to the top of the column main body, a concentrating section is provided above, a second distillation section provided with a collecting section below, and at least a portion is disposed adjacent to the column bottom of the column main body. A distillation apparatus having a third distillation section provided with an enrichment section above and a recovery section below, wherein (a) a stock solution is supplied to the first distillation section; Discharging the distillate at the top, (c) selecting at least one of the plurality of side cut nozzles disposed on the tower side, discharging the side cut liquid from the selected side cut nozzle, (d) E) discharging the bottoms at the bottom of the column; How to stay.