JP2003220301A - Distillation purifying method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a cost and to obtain a component B of high purity in a distillation purifying method wherein raw material containing four components A, B, C, D whose boiling point goes higher in alphabetical order, while the components A, C being less than B, D, is distilled to four cuts, whose middle cut is rich in the component B. <P>SOLUTION: The raw material is supplied to a first compartment of a common distillation tower, the inside of which is divided with a vertical partition wall, and a light cut containing the concentrated component A is distilled out. Then in the intermediate room, vapor being rich in the components B, C, and liquid being rich in the component D is separated and supplied respectively to a third, second, and fourth compartment. A middle cut containing the concentrated component B in the third compartment and a heavy cut containing the concentrated component D in the second compartment are each distilled out, while a semi-heavy cut containing the concentrated component C is distilled out of the fourth compartment. Thus each component is distilled out to obtain the component B of high purity. And in this case, the heat consumption in the distillation can be reduced because reflux capacity can be reduced. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a distillation purification method for separating a raw material containing at least four components into four fractions having a lower boiling point in the order of a light fraction, an intermediate fraction, a semi-heavy fraction and a heavy fraction. .

[0002]

2. Description of the Related Art When a plurality of components are separated into each component by distillation, for example, the boiling points are component A, component B, component C,
A raw material containing at least four components A, B, C, and D, which are lower in the order of the component D and in which the components A and C are smaller than the components B and D, have a boiling point of a light fraction, an intermediate fraction, and a semi-heavy fraction. , The heavy fraction may be separated into four fractions which become lower. Specifically, the case of purifying crude methanol can be mentioned. That is, for example, by distilling crude methanol containing carbon dioxide, methane, methanol, ethanol and water,
It is separated into carbon dioxide and methane as a light fraction, methanol as an intermediate fraction, a mixture containing ethanol and methanol and water (fusel oil) as a semi-heavy fraction, and water as a heavy fraction, and recovered.

As a conventional method for performing such purification, for example, as shown in FIG. 7A, for example, a first distillation column 12a having a condenser 10a and a reboiler 11a, and a condenser 10 are provided.
There is used a distillation apparatus having a two-column system in which b and a reboiler 11b are connected and a second distillation column 12b provided with a side cut in the middle stage is connected. According to this distillation apparatus, first, the raw material supplied to the middle part of the first distillation column 12a is distilled in the first distillation column 12a to produce the first distillation column 12a.
From the upper part of the distillation column 12a of
Fluids rich in component B, component C, and component D are discharged from the lower side, respectively. Then, the fluid enriched in the components B, C and D is supplied to the middle stage of the second distillation column 12b and distilled, and the fluid enriched in the component B is supplied from the upper side of the second distillation column 12b. The fluid rich in component C is discharged from the side cuts in the middle part, and the fluid rich in component D is discharged from the lower side. In this way, the raw materials are the components A, B,
Separated into C and D.

Another method is a three-column system in which a side cut is not provided in the second distillation column 12b of FIG. 7 (a), and a third distillation column is provided in the subsequent stage of the second distillation column 12b. Distillation equipment is also used.

Furthermore, application of the apparatus shown in FIG. 7 (b) for separating a ternary raw material into three fractions has also been studied. In this device, a vertical partition plate 14 is provided inside a distillation column 13, and a first division chamber 15 is in communication with each other.
The second division chamber 16 and the third division chamber 17 are formed in the distillation column, and a brief description will be given of the case where the second division chamber 16 and the third division chamber 17 are applied to a three-component system raw material. A raw material containing components A, B, and C is supplied to the middle section 42 of the first division chamber 15 and distilled to obtain a fluid rich in components A and B from the upper portion of the first division chamber 15 and from the lower portion. The fluids rich in component C are discharged respectively. The fluid rich in the components A and B is distilled in the second division chamber 16 to separate the component B, and the fluid rich in the component A is discharged from the top of the distillation column 13. On the other hand, the separated fluid rich in component B is discharged from the middle stage of the column. Further, the fluid rich in the component C separated in the first dividing chamber 15 exits from the first dividing chamber 15 and is discharged into the third dividing chamber 15.
Of the component B remaining therein is separated into a fluid rich in component C and discharged from the bottom of the distillation column 13.

[0006]

However, as shown in FIG.
In the two-column type distillation apparatus shown in (a), a plurality of distillation columns are required, and more piping and instrumentation equipment are required, resulting in higher facility costs, and also because a large amount of heat is required, operating costs are also higher. Get higher

The vertical separation type distillation column 13 shown in FIG. 7 (b) is suitable for separating a raw material into a light fraction, an intermediate fraction, and a heavy fraction. In the case where it is necessary to remove a trace component of quality to an extremely low concentration, the characteristics are not sufficiently exhibited. That is, four components A, B,
When the raw material containing C and D is separated into four fractions, a side cut nozzle is newly provided on the side wall of the distillation column 13 to separate into the four fractions as shown in FIG. Compared with the case of separating into three fractions, the take-out positions of the respective fractions provided in the distillation column 13 become closer, and, for example, the concentration of the component A or the component C in the target component B becomes high. I have a concern. As one of the solution methods in that case, in order to increase the purity of the component B, it is conceivable to increase the reflux ratio or increase the theoretical plate number of the distillation column 13 to improve the separation efficiency. In the former case, In the latter case, the cooling heat amount of the condenser and the heating heat amount of the reboiler at the time of distillation increase, and the manufacturing cost increases. In the latter case, the distillation column 13 may increase in size and the equipment cost may increase.

The present invention has been made under these circumstances, and its purpose is to have a lower boiling point in the order of component A, component B, component C, and component D, and components A and C are lower than components B and D. A raw material containing a small amount of at least four components A, B, C, D is separated into four fractions having a lower boiling point in the order of a light fraction, an intermediate fraction, a semi-heavy fraction, and a heavy fraction, It is an object of the present invention to provide a technique capable of obtaining a highly pure component B in a distillation purification method in which the middle distillate is rich in component B, and at the same time reducing the cost of distillation.

[0009]

In the distillation purification method of the present invention, the boiling points are lower in the order of component A, component B, component C, component D, and the amount of components A and C is smaller than that of components B and D. A raw material containing components A, B, C, and D has a lower boiling point in the order of light fraction, middle fraction, semi-heavy fraction, and heavy fraction. 4
In the distillation purification method in which one fraction is separated into two fractions, and the middle fraction is rich in component B, the upper part of the column body is divided into a first division chamber and a third division chamber by a vertical upper partition wall and The lower part of the tower body is divided into two parts by the vertical lower partition wall.
Divided into a fourth divided chamber and a divided chamber divided by an upper partition wall and a divided chamber divided by a lower partition wall are communicated with each other by an intermediate chamber between the upper partition wall and the lower partition wall. A step of supplying the raw material to the first division chamber by using a distillation column, and taking out the light fraction from the upper portion of the first division chamber, and at the
In the step of supplying the second divided chamber from the divided chamber to the second divided chamber, and in the intermediate chamber and the second divided chamber, the vapor rich in components B and C is obtained from the liquid, and the third chamber is obtained. Of the heavy fraction from the lower portion of the second division chamber while supplying the intermediate fraction from the steam in the third division chamber. Of the liquid from which the middle distillate has been separated and is supplied to the fourth division chamber from the third division chamber through the middle chamber,
A step of obtaining the vapor of the semi-heavy fraction and the liquid of the heavy fraction from the liquid in which the middle distillate has been separated in the fourth division chamber, and taking out the vapor from the upper part and the lower part of the fourth division chamber, respectively. It is characterized by including.

Incidentally, "the boiling points are Component A, Component B, Component C,
"Lower in order of component D" means that A has a lower boiling point than B, B has a lower boiling point than C, and C has a lower boiling point than D. , In order of the heavy fraction, the lighter fraction has a lower boiling point than the middle fraction, the middle fraction has a lower semi-heavy fraction, and the semi-heavy fraction has a lower boiling point than the heavy fraction. Is the meaning. Further, the "distillate" means each fluid obtained when the mixed fluid containing a plurality of components is fractionally distilled in several temperature sections. Further, "to divide into a first division chamber and a third division chamber on the left and right" does not mean that the first division chamber is located on the left and the third division chamber is located on the right, but is divided horizontally. Is. The same applies to “divided into the second divided chamber and the fourth divided chamber on the left and right”.

The heavy fraction may be enriched with component D, for example. Component B, Component C and Component D
May be, for example, methanol, ethanol and water, for example acetone, isopropanol and water and mesityl oxide. Further, in the upper part of the intermediate chamber, for example, a steam distributor that distributes more steam from the intermediate chamber to the third divided chamber than to the first divided chamber may be provided. At the bottom of
For example, a liquid distributor that distributes the liquid from the intermediate chamber to the second divided chamber more than the fourth divided chamber may be provided. Furthermore, the uppermost part of the distillation column may be divided by the upper partition wall, and the lowermost part of the distillation column may be divided by the lower partition wall.

According to the distillation purification method of the present invention, the boiling points are lower in the order of Component A, Component B, Component C, and Component D, and Component A,
At least 4 components A, where C is less than components B, D,
When a raw material containing B, C and D is distilled, each of the components A, B, C and D is stored in the first, second, third and fourth division chambers provided inside the common distillation column 20. The components can each be concentrated. That is, by concentrating the component B in the second division chamber, the purity of the component B is increased and it can be obtained as an intermediate fraction. Further, by concentrating each component in each division chamber, the component B can be made to have a predetermined purity even if the gas-liquid contact amount in the distillation column, for example, the reflux amount is reduced. Therefore, the amount of heat used during distillation is suppressed, and the operating cost can be reduced.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION First, an example of a distillation apparatus used in the method of the present invention will be described with reference to the conceptual diagram shown in FIG. The distillation apparatus 2 is provided with a distillation column 20 which is, for example, a cylindrical vertical distiller, and inside the distillation column 20, there are a plurality of trays, for example trays, for performing gas-liquid contact as described later. There are 50 steps. When a tray is provided, the number of theoretical trays in the theoretical tray is counted downward from the uppermost tray. On the upper side of the distillation column 20, an upper partition wall 21 which is a first partition member is provided vertically in the vertical direction, for example, from the uppermost part of the distillation column 20 to the 25th stage, and the upper partition wall 21 allows the It is divided into a first division chamber 22 and a third division chamber 23. Similarly, on the lower side of the distillation column 20, a lower partition wall 24 which is a second partition member is also provided vertically in the vertical direction from the 41st stage to the lowermost part of the distillation column 20. Is divided into a second divided chamber 25 and a fourth divided chamber 26 on the left and right. Further, an intermediate chamber 27 is formed between the upper partition wall 21 and the lower partition wall 24, and the first division chamber 22 and the third division chamber 23 are communicated with the intermediate chamber 27 via the vapor distributor 28. In addition, the second division chamber 24 and the fourth division chamber 25 are connected to the liquid distributor 2
It communicates with the intermediate chamber 27 via 9.

Next, an example of the tray will be described with reference to FIGS. 2 shows an example of trays provided in the second division chamber 25 and the fourth division chamber 26, and FIG. 3 shows trays provided in the first division chamber 22 and the third division chamber 23. An example is shown. First, as shown in FIG. 2, the first trays 30 and the second trays 31 are alternately provided in the vertical direction at the same intervals by the theoretical number of stages. The first tray 30 is provided with a liquid support plate 32 for supporting a liquid flowing down from the upper side of the distillation column 20, with its peripheral edge and the inner wall of the distillation column 20 sealed with, for example, a gasket. The lower partition wall 24 is provided on the center line of the liquid support plate 32 so as to intersect the surface. Further, in the liquid support plate 32, for example, a half-elliptical flow hole 33 (33) is provided on the left and right sides via the lower partition wall 24.
a, 33b) are formed, and the edge of each hole is erected upward to form a dam portion 34 (34a, 34b) for supporting a predetermined amount of liquid on the liquid support plate 32, and A downcomer unit 3 for raising the edge of the hole also in the downward direction and supplying the liquid to the tray on the next stage through the flow hole 33.
5 (35a, 35b) are formed.

Further, the liquid support plate 32 is provided with a plurality of, for example, circular through holes 36 for allowing the vapor to pass upward from below, and the vapor passing through the through holes 36 during distillation is provided. And the liquid supported by the liquid support plate 32 come into gas-liquid contact with each other to form a gas-liquid equilibrium state. That is, when the vapor containing a plurality of components and the liquid are brought into gas-liquid contact with each other, the component having a low boiling point is mainly vaporized, and the component having a high boiling point is liquefied to separate each component. The liquid support plate 32
To prevent the liquid above from flowing down from the flow holes 36,
That is, it is preferable to set the steam flow rate so that weeping does not occur. Furthermore, the tip of the downcomer section 35 is immersed in the liquid on the tray at the next stage so that the steam does not pass through the downcomer section 35 and flow upward without contacting the gas and liquid (short path). It is set at a height position where it is water-sealed.

Like the first tray 30, the second tray 31 is provided with a liquid support plate 32 and a flow hole 35, and the liquid flows laterally on the liquid support plate 32 to some extent. For example, a rectangular flow hole 33 (33c, 33d) is formed in a place different from the first tray 30 so as to be retained, and the edge of the hole is erected upward and downward so that the weir portion 34 ( 34c, 34d) and the downcomer portion 35 (3
5c, 35d) are formed.

Here, the liquid distributor 29 is, for example, the first
A tray having the same structure as the tray 30 (the tray described in the uppermost stage in the drawing) is used, but the trays are made to flow down from the passage holes 33a by changing the sizes of the passage holes 33a and 33b. It has a distribution function of adjusting the amount of liquid and the amount of liquid flowing down from the flow hole 33b. In this example, the flow passage hole 33a provided on the second division chamber 25 side is larger so that the liquid from the intermediate chamber 27 is supplied to the second division chamber 25 more than the fourth division chamber 26. It is set.

Next, an example of trays provided in the first division chamber 22 and the third division chamber 23 will be described with reference to FIG.
Also in the first division chamber 22 and the third division chamber 23, the above-mentioned first tray 30 and second tray 31 are divided into left and right by the upper partition wall 21 and are alternately provided at predetermined intervals. Further, on the lower side of the tray provided at the lowest stage of the first division chamber 22 and the third division chamber 23,
The vapor distributor 28 is provided so that the downcomer portion 35 of the lowermost tray penetrates. This vapor distributor 28 is divided into left and right by the upper partition wall 21 like the tray on the upper stage side, and the number or size is further divided into the first division chamber 22 side and the third division chamber 23 side. Different flow holes 37a and 37b are provided respectively, and have a distribution function of adjusting the flow rate of steam passing through the steam distribution unit 28 by changing the opening area ratio. That is, the opening area on the third division chamber 23 side is set to be larger so that the vapor from the intermediate chamber 27 is supplied to the third division chamber 23 more than the first division chamber 25. The tray shown at the lower back in the figure is the tray corresponding to the uppermost stage of the intermediate chamber 27.
Also in the above, the first tray 30 and the second tray 31 are alternately provided.

Returning to FIG. 1, above the distillation column 20, the first vapor for liquefying the vapor discharged from the upper end of the first division chamber 22 to be a reflux liquid and a bottom liquid is obtained. The condenser 40 is connected via a flow path such as a pipe, and the third
Liquefy the vapor discharged from the upper end of the division chamber 23 of
A second condenser 41 for making the reflux liquid is connected via a flow path, for example, a pipe.

Further below the distillation column 20, there is a first for vaporizing the liquid discharged from the lower end of the second division chamber 25.
Of the second reboiler 42 for vaporizing the vapor discharged from the lower end of the fourth division chamber 26 is connected through a flow path such as a pipe. Connected. For the first condenser 40 and the second condenser 41, for example, a multi-tube heat exchanger capable of exchanging heat with cold water is used, and the first reboiler 42 and the second reboiler 43. For example, a multi-tube heat exchanger capable of exchanging heat with steam is used.

Further, a raw material supply port 50 for supplying a raw material is provided in the middle stage portion of the first division chamber 22, for example, the tenth stage. A first side-cut nozzle 51 for discharging the middle distillate is provided on the upper side of the third division chamber 23, for example, on the second stage, and the first side cut nozzle 51 for discharging the middle distillate is provided on the upper side, for example, the 46th stage of the fourth division chamber 26. A second side cut nozzle 52 is provided for discharging the heavy fraction. The raw material supply port 5
0, the first side-cut nozzle 51 and the second side-cut nozzle 52 are connected to channels, for example, pipes.

Next, the step of distilling the raw material using the above-mentioned distillation apparatus 2 will be described. In this embodiment, a raw material containing at least four components A, B, C, and D whose boiling points are lower in the order of component A, component B, component C, and component D, and component A, C is smaller than components B, D. For example, a fluid containing carbon dioxide, methanol, ethanol and water is distilled and separated into four fractions of a light fraction, an intermediate fraction, a semi-heavy fraction and a heavy fraction, and the component B is used as a target product. A method of obtaining the data will be described. First, the raw material is supplied to the middle part of the first division chamber 22 through the raw material supply port 50. Here, the raw material is distilled, and a vapor in which the component A, which is a light fraction having a low boiling point, is concentrated is obtained from the upper portion of the first division chamber 22. This light fraction is liquefied in the first condenser 40 and a part of it is discharged as a bottom liquid to the outside of the apparatus, while the rest is returned to the first division chamber 22 as a reflux liquid. On the other hand, the light fraction is separated, and the liquid containing the components B, C, and D flows down to the tray of the next stage through the downcomer section 35, exits the lower portion of the first division chamber 22 and is supplied to the intermediate chamber 27. To be done.

The components B, C, supplied to the intermediate chamber 27
The liquid containing D is distilled in the intermediate chamber 27 and the components B and C having a low boiling point are mainly vaporized, and the vapor rich in the components B and C goes out from the upper portion of the intermediate chamber 27. In this case, since the purpose is to obtain the component B having a high purity as the middle distillate, the first side cut nozzle 51 for discharging the middle distillate by the distribution function of the vapor distributor 28 described above.
Is mainly supplied to the side of the third division chamber 26 in which is provided. The vapor rich in the components B and C supplied to the third division chamber 23 is separated by liquefying the component C by distillation in the third division chamber 23, and the component C is separated from the upper portion of the third division chamber 26. The steam enriched with B is discharged. Thereafter, the vapor is liquefied in the second condenser 41 and returned to the third division chamber 23 as a reflux liquid by total reflux, and the liquid rich in the component B is discharged from the first side-cut nozzle 51 into an intermediate distillate fraction. Is discharged as. Note that a small amount of purging may be performed instead of total reflux. On the other hand, the liquefied liquid rich in the component C is discharged from the lower part of the third division chamber 23 and returned to the intermediate chamber 27.

On the other hand, in the liquid containing the components B, C and D supplied from the first division chamber 22 to the intermediate chamber 27, the component D having a high boiling point is mainly liquefied in the intermediate chamber 27, and the third component
Also in the liquid rich in the component C returned from the division chamber 23, the component D therein is mainly liquefied. This component D
The rich liquid is discharged from the lower part of the intermediate chamber 27, but in order to concentrate the component C to the fourth division chamber 26 side, part of it is divided into the fourth division by the distribution function of the liquid distribution unit 29 described above. Chamber 26
Supplied to the side. The remaining liquid is supplied to the second division chamber 25, the remaining component C is vaporized and separated by distillation, and the separated component C exits from the upper portion of the second division chamber 25 and is returned to the intermediate chamber 27. . On the other hand, the liquid in which the component C is separated and the purity of the component D is increased is discharged from the lower part of the second division chamber 25 and the bottom part of the distillation column 20, but a part of the liquid is discharged from the first recycle chamber. It is vaporized by the heater 42 and returned to the second division chamber 25, and the rest is discharged as a heavy component to the outside of the apparatus through a pipe.

Furthermore, the liquid supplied to the fourth division chamber 26 is separated from the component C by liquefying the component D by distillation in the fourth division chamber 26. The separated liquid rich in component D is discharged from the lower part of the fourth division chamber 26 and discharged from the bottom part of the distillation column 20, but a part thereof is vaporized in the fourth reboiler 43. It is returned to the fourth division chamber 26, and the rest is discharged to the outside of the device through the pipe. On the other hand, the component C vaporized and separated by distillation in the fourth division chamber 26 is converted into a semi-heavy fraction from the second side cut nozzle 52 provided on the upper side of the fourth division chamber 26. Is discharged.

In such an embodiment, the boiling points are lower in the order of Component A, Component B, Component C and Component D, and the amount of Components A and C is smaller than that of Components B and D. When the raw materials containing C and D are distilled, the first dividing chamber 22 provided inside the common distillation column 20 has the component A, the third dividing chamber 23 has the component B, and the second dividing chamber 25. Can be separated so that the component D can be concentrated in the fourth division chamber 26 and the component C can be concentrated in the fourth division chamber 26. That is, the above raw materials are distilled in a common distillation column 20 to obtain a light fraction, an intermediate fraction, a semi-heavy fraction,
The heavy fraction can be separated into four fractions, at which time the highly pure component B (target product) can be obtained as an intermediate fraction.
Therefore, for example, when crude methanol is used as a raw material, carbon dioxide or methane as a light fraction by distillation, methanol as an intermediate fraction, ethanol as a semi-heavy fraction, a mixture of methanol and water (fusel oil) ,
It can be separated into water as a heavy fraction, and methanol having a high purity can be obtained as the middle distillate. Further, since the distillation column 20 is a single column type, the facility cost can be suppressed, and the amount of heat consumed during the distillation can be small, so that the operation cost can be suppressed. That is, the cost of distillation can be reduced.

Further, in the present invention, as will be apparent from the examples described later, the amount of heat consumed during distillation in the condenser and reboiler can be suppressed. That is, for example, the distillation column of FIG. 7 (b), which is suitable for separating into three fractions (hereinafter referred to as a conventional type), is used to separate into four fractions, as described above, and the purity of the target product. Will decrease. Therefore, in order to obtain the target substance having the same purity as the target substance obtained by the method of the present invention, the separation efficiency must be better than that in the case of the 3 fractions. The means for improving this separation efficiency is to increase the reflux ratio and increase the flow rate of the vapor / liquid flowing vertically in the column to increase the ratio of gas-liquid contact. The load on the condenser must be increased, and the amount of heat consumed is large. In other words, in the case of separating the above-mentioned raw material into four fractions,
Compared with the conventional method, the method of the present invention can obtain the target substance with high purity even if the load on the reboiler and the condenser is reduced, so that the amount of heat consumed can be suppressed.

Since the concentration of the component A in the raw material is very small, the reflux liquid becomes a liquid rich in the component B having the second lowest boiling point in both the conventional method and the method of the present invention. Considering the condenser here, the vapor discharged from the top of the conventional distillation column contains the component A concentrated by distillation. On the other hand, in the distillation purification method of the present invention, since the A component has already been separated from the reflux liquid in the third division chamber 23 and the A component is not contained in the B component, the reflux amount is small. Therefore, the amount of cooling heat can be suppressed.

In order to further raise the purity of the component D, considering the reboiler, in order to raise the purity of the liquid rich in the component D discharged from the bottom of the distillation column 20, the component C should be as much as possible. It needs to be vaporized. In the conventional method, the liquid containing the C component and rich in the D component is vaporized, but in the method of the present invention, the C component is concentrated in the fourth division chamber 26 so that it is discharged from the second division chamber 25 side. The liquid containing almost no component C. Therefore, the first reboiler 4
2 can suppress the amount of heating heat.

The method of the present invention is not limited to the case where only the component B is the target product, and the component D may be the target product, or the component B and the component D may be the target product. Even in this case, the same effect as the above case can be obtained. Further, the distillation column 20 used in the method of the present invention is not limited to the above-mentioned configuration in which the tray is provided, and may be a configuration in which a packing, for example, a pole ring is packed, or a tray or a packing is provided in each divided chamber. You may do it.
Further, the flow hole 36 provided in the above tray may be constituted by a valve cap. Even in such a configuration, gas-liquid contact can be made and separated into each fraction,
The same effect as the above case can be obtained.

Furthermore, the upper partition wall 21 and the lower partition wall 24 are not limited to the structure provided on the center line of the distillation column 20, and may be eccentrically provided, and the uppermost part or the lowermost part of the distillation column 20 is completely provided. The upper partition wall 21 and the lower partition wall 24 may be provided so as not to be divided into two parts, but it is preferable to determine how to provide them by performing a simulation or a test in advance depending on the components of the supplied raw materials. . Even in such a case, the same effect as the above case can be obtained.

[0032]

EXAMPLES Next, examples carried out to confirm the effects of the present invention will be described. (Example 1) In this example, 0.51% by weight of a light component such as methane (component A), 78.34% by weight of methanol (component B), 0.15% by weight of ethanol (component C), water ( It is Example 1 in which a raw material containing 21% by weight of component D) was distilled. As shown in FIG. 4, the upper partition wall 21 is provided from the uppermost part of the distillation column 20 to the 30th theoretical plate, and the lower partition wall 24 is provided from the 41st theoretical plate to the distillation column 2.
Using a distillation column provided over the lowest part of 0 and divided into first, second, third and fourth division chambers, a flow rate of 1350 kg / h is provided in the middle part of the first division chamber 22. The raw material of 54 degreeC was supplied. At this time, the middle distillate was discharged at 1019 kg / h from the second theoretical plate, and the semi-heavy fraction was discharged at 21 kg / h from the 45th plate. Further, a light component was discharged from the top of the distillation column 20 at 32 kg / h, and 277 kg / h (= 100 kg / h + 177 kg /) from the bottom of the distillation column 20.
The heavy fraction was discharged in h). The composition of the components discharged from each part is also shown in FIG.

(Comparative Example 1) This example is Comparative Example 1 in which the raw material having the same composition as in Example 1 was distilled using a two-column distillation apparatus.
As shown in FIG. 5, the distillation apparatus includes a first distillation column 12a having 30 theoretical plates and a second distillation column 12b having 50 theoretical plates.
Was used to supply the raw material at 54 ° C. to the middle part of the first distillation column 12a at a flow rate of 1350 kg / h as in Example 1.
At this time, the light fraction is discharged from the top of the first distillation column 12a at 30 kg / h, and in the second distillation column 12b, the middle fraction is discharged at the theoretical plate number from the second stage to 1020 kg / h.
The semi-heavy fraction was discharged from the 42nd stage at 21 kg / h, and the heavy component was discharged from the bottom 12b of the second distillation column at 277 kg / h. The composition of the components discharged from each part is also shown in FIG.

(Example 2) This example is Example 2 in which raw materials having different components were distilled using the same distillation column 20 as in Example 2. As a raw material, a light component such as propylene (component A) is 0.
1% by weight, the target product of acetone (component B) is 58.8.
A fluid containing 2% by weight, 6.18% by weight of isopropanol (component C), 32.52% by weight of water (component D) and 2.38% by weight of mesityl oxide (component D) was used. At this time, the number of theoretical plates is 2 with respect to the mass flow rate of the raw material.
The middle distillate was discharged at a flow rate of 58.6% from the stage, and the semi-heavy fraction was discharged at a flow rate of 7% from the 45th stage. Further, the light component is discharged from the upper part at a flow rate of 0.03%, and the
It was discharged at a flow rate of%. The composition of the components discharged from each part is shown in FIG.

(Consideration of Example 1 and Comparative Example 1) As is clear from the results of Example 1 shown in FIG. 4, the methanol contained in the middle distillate has a purity extremely close to 100% by weight, and Moisture contained in heavy fraction is 99.71% by weight
The purity is higher than the above. Since the purity is slightly different from the result of Comparative Example 1 shown in FIG. 5, the raw material containing at least four or more components was subjected to the common distillation column in the light fraction, the middle fraction, and the semi-weight fraction. It was confirmed that it was possible to separate into 4 fractions of the quality component and the heavy component, and to obtain the target product, which was highly pure methanol, as an intermediate fraction. In Example 1, the first reboiler 42 has 513 kW, the second reboiler 43 has 679 kW, and the first condenser 40 has 16
In the second condenser 41, a heat amount of 1138 kW is used, and a total heat amount of 2346 kW is consumed, whereas in Comparative Example 1, a heat amount of 2707 kW is consumed. From this, it is clear that the method of the present invention can reduce the amount of heat by 15%. Here, when the inventor uses the distillation column of FIG.
It has been confirmed by simulation that the heat amount of 7 kW is consumed. That is, the method of the present invention can reduce the amount of heat as in the case described above.

(Consideration of Example 2) As is clear from the results shown in FIG. 6, light components such as propylene, acetone,
Even when a raw material containing isopropanol, water and mestyl oxide was distilled, the middle fraction acetone had a purity of 99.98% by weight, and the heavy fraction water and mesityl oxide had a purity of 99.98%. It has a purity of 59% by weight. That is, even if the components (substances) contained in the raw materials are different, the acetone of high purity can be separated into four fractions of a light fraction, an intermediate fraction, a semi-heavy component and a heavy component by the method of the present invention. It was confirmed that can be obtained as a middle distillate.

As described above, according to the present invention, the boiling points are lower in the order of Component A, Component B, Component C and Component D, and Component A,
At least 4 components A, where C is less than components B, D,
A raw material containing B, C, and D is distilled to obtain four fractions having a lower boiling point in the order of light fraction, middle fraction, semi-heavy fraction, and heavy fraction, and the middle fraction is component B. In the distillation purification method in which the separation is enriched, the component B having high purity can be obtained and the cost of distillation can be reduced.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an example of distillation equipment equipped with a distillation purification method of the present invention.

FIG. 2 is a perspective view showing an internal configuration of a distillation column of the distillation facility.

FIG. 3 is a perspective view showing an internal configuration of a distillation column of the distillation facility.

FIG. 4 is a characteristic diagram showing an example performed to confirm the effect of the present invention.

FIG. 5 is a characteristic diagram showing an example performed to confirm the effect of the present invention.

FIG. 6 is a characteristic diagram showing an example performed to confirm the effect of the present invention.

FIG. 7 is an explanatory diagram showing a conventional distillation facility.

FIG. 8 is an explanatory view showing a conventional distillation facility.

[Explanation of symbols]

2 distillation equipment 20 distillation tower 21 Upper partition wall 22 First division room 23 Third division room 24 Lower partition wall 25 Second division room 26 Fourth division room 27 Intermediate room 30 First tray 31 Second tray 40 First condenser 41 Second condenser 42 First Reboiler 43 Second reboiler

─────────────────────────────────────────────────── ─── Continued Front Page (51) Int.Cl. ⁷ Identification Code FI Theme Coat (Reference) C07C 31/10 C07C 31/10 45/82 45/82 49/08 49/08 J 49/203 49/203 JF term (reference) 4D076 AA16 AA22 AA23 AA24 BA35 BB05 CA12 CA14 4H006 AA02 AD11 BD82 BD84 FE11

Claims (8)

[Claims] 1. A boiling point of component A, component B, component C, component D
In the order of, and the components A and C are smaller in amount than the components B and D, and at least four components A, B, C and D are used as raw materials, and the boiling points are light fraction, middle fraction, semi-heavy fraction and heavy fraction. In the distillation purification method in which the fraction is separated into four lower fractions in order, and the middle fraction is rich in component B, the upper part of the column main body is divided into the first dividing chamber and the first dividing chamber by the vertical upper partition wall. It is divided into three division chambers, and the lower part of the tower main body is divided into a second division chamber and a fourth division chamber by the vertical lower partition wall.
Using a distillation column, which is divided into two division chambers, the division chamber divided by the upper partition wall and the division chamber divided by the lower partition wall communicate with each other by the intermediate chamber between the upper partition wall and the lower partition wall. A step of supplying a raw material to the first division chamber, a light fraction is taken out from an upper portion of the first division chamber, and a liquid from which the light fraction is separated is passed from the first division chamber to the intermediate chamber. Through the step of supplying to the second divided chamber via the intermediate chamber and the second divided chamber, while obtaining vapors rich in components B and C from the liquid and supplying the vapor to the third divided chamber, A step of taking out the heavy fraction from the lower part of the second division chamber, and obtaining an intermediate fraction from the steam in the third division chamber and taking it out from the upper part of the third division chamber, The separated liquid from the third division chamber through the intermediate chamber to the fourth division chamber And a step of supplying the semi-heavy fraction vapor and the heavy fraction liquid from the liquid from which the middle distillate has been separated in the fourth division chamber, and the upper and lower portions of the fourth division chamber, respectively. And a step of removing from the distillation purification method. 2. The distillation purification method according to claim 1, wherein the heavy fraction is rich in component D. 3. The distillation purification method according to claim 1, wherein the components B, C and D are methanol, ethanol and water. 4. The distillation purification method according to claim 1, wherein the components B, C and D are acetone, isopropanol, water and mesityl oxide. 5. A vapor distributor for distributing vapor from the intermediate chamber so as to supply more vapor to the third divided chamber than to the first divided chamber, at the upper part of the intermediate chamber. The distillation purification method according to any one of claims 1 to 4. 6. A liquid distributor for distributing the liquid from the intermediate chamber to the second divided chamber more than the fourth divided chamber is provided in the lower portion of the intermediate chamber. The distillation purification method according to any one of claims 1 to 5. 7. The distillation purification method according to claim 1, wherein the uppermost part of the distillation column is divided by the upper partition wall. 8. The distillation purification method according to claim 1, wherein the lowermost part of the distillation column is divided by the lower partition wall.