JP2002177701A - Batch packed distillation method and batch packed distillation equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a batch packed distillation method which is capable of making best possible use of the performance of batch packed distillation equipment by changing a reflux ratio so as to maintain the instantaneous minimum theoretical steps always constant from the beginning to the end of batch packed distillation and is capable of improving a recovery rate by efficiently effecting the batch packed distillation of a distillation stock solution under conditions under which separation performance is optimized without requiring enormous repetitive calculations and the batch packed distillation equipment for the same. SOLUTION: The batch packed distillation method of separating the distillation stock solution containing a light key component of a low boiling point and a heavy key component of a high boiling point to a distillate and a residue respectively at prescribed recovering rates while performing a reflux operation by using a batch packed distillation column comprises using the batch packed distillation column having theoretical steps N greater than the minimum theoretical steps Sm-1 defined by (mathematical expression 1) and performing the distillation by regulating the reflux ratio in the reflux operation to make the instantaneous minimum theoretical steps SM defined by (mathematical expression 2) coincident with the minimum theoretical steps Sm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a batch packing distillation method and a batch packing distillation apparatus having excellent separation efficiency.

[0002]

2. Description of the Related Art In recent years, batch filling distillation has been widely used in the field of fine specialty chemicals, and fine specialty chemicals are required to recover expensive and highly pure substances in high yields. However, the batch filling distillation operation is performed based on past experience, and a considerable amount of expensive products may be lost without being collected. Have been. Conventionally, in a distillation operation using a batch packed distillation column, the reflux ratio between the reflux liquid refluxed to the batch packed distillation column and the distillate removed from the batch packed distillation column is preset by an empirical method such as trial and error. However, a constant reflux ratio operation method for maintaining the reflux ratio constant is employed. In batch-packing distillation based on such a constant reflux ratio operation method, the economical optimal conditions may be far from economically optimal conditions because the vapor component greatly changes between the initial stage and the latter stage of the distillation. 1 (Sundara
m. S, and Evans. L. B ,: Ind.
Eng. Chem. Res. 32, p511 (1
There is a need for a systematic methodology for the design and operation of batch packed distillation as shown in 993)).

[0003] That is, the method of operating at a constant reflux ratio has advantages such as easy operation and stable operation. However, in the batch filling distillation operation, as the low boiling point component decreases as the distillation proceeds, this separation is difficult. The required reflux ratio increases. Therefore, in the constant reflux ratio operation, the reflux ratio is initially operated more than necessary, but as the end point of the distillation is approached, the concentration of the low-boiling component in the bottom liquid decreases, and the reflux ratio becomes less than the minimum reflux ratio. The state becomes a point, and it becomes difficult to effectively perform the separating operation. In addition, if an attempt is made to increase the recovery rate of the required components by a constant reflux ratio operation method, the reflux ratio required to obtain the same with a predetermined purity increases, the amount of steam required for heating increases, and the production capacity increases. It drops sharply. Therefore, it is often not possible to obtain a large recovery rate per batch from an economic viewpoint. If the reflux ratio is not appropriately set, the recovery rate of the active ingredient is reduced. Therefore, in order to operate efficiently, the reflux ratio is appropriately increased according to the decrease in the low boiling components in the bottom composition. It is necessary.

On the other hand, as a method for obtaining an optimum reflux ratio in batch packed distillation, Pontryagin (Pontryagin) is used.
Optimal Flux Policy (Optimal Flux Poli) using an optimization method of Agin
cy) is described in Reference 2 (Sandaram. Sa).
nd Evans. L. B: Ind. Eng. )
And Reference 3 (Morimoto, Suzuki: Chemical Engineering Transactions 25, No3,
p411 (1999)).

Regarding the control of the reflux ratio in a batch packed distillation column, for example, Japanese Patent Publication No. 4-51201 (hereinafter referred to as "A") discloses a detecting means for detecting the temperature and pressure of steam at the bottom and inside of the column. And a composition calculating means for calculating the vapor composition in the bottom and in the column based on the detected temperature and pressure, and calculating a reflux ratio which is a set theoretical plate number based on the calculation result and the set top vapor composition. Reflux ratio calculating means, a flow control valve for controlling the amount of reflux in accordance therewith, second detecting means for detecting the temperature and pressure of the steam at the top, and overhead steam calculated based on the detected value A control device for batch distillation comprising a correction means for resetting the number of theoretical plates according to the difference between the composition and the set composition is described.

[0006]

However, the conventional batch-packing distillation method and apparatus for changing the reflux ratio have the following problems. (A) In the generally employed operation method with a constant reflux ratio, there is a problem that it is difficult to effectively utilize the separation performance of the distillation column for several high theoretical stages because of the presence of a pinch point. (B) In the case of operating at a low reflux ratio, even if a distillation column having a high theoretical number of plates is used, it becomes a pinch point, and the separation performance is not exhibited because the number of stages of the distillation column does not work effectively. Also, if a distillation column with a high reflux ratio and a high number of theoretical plates is used from the beginning, a large amount of distillation time is required, and energy saving is lacking.
There was a problem that the cost would be high. (C) The method of mathematically obtaining the reflux ratio shown in the above-mentioned Documents 2 and 3 based on an optimization method requires inputting a large number of set condition values in advance, and furthermore, complicated calculations are repeated. A general computer consumes a lot of time to find the conditions, and if the calculation speed is increased, a large computer is required, and it is difficult to apply the method to an actual distillation operation. (D) The reflux ratio control device disclosed in the publication No. A detects the temperature and pressure at the top of the column and resets the theoretical plate number in accordance with the detected values to change the reflux ratio. Fluctuates, and it is difficult to efficiently perform batch packed distillation of the distillation stock under appropriate conditions where the number of theoretical plates is constant.
For this reason, there has been a problem that the distillation time required to obtain a predetermined amount of distillate is long, and the productivity is inferior and the production cost is high, and the economic efficiency is reduced. (E) Further, according to the publication No. A, the vapor composition is calculated by detecting the temperature and pressure of the vapor in each part of the distillation column, and the amounts of the distillate and the reflux liquid are indirectly calculated based on the vapor composition value. As a result, measurement time lags and errors occur, and the yield of light key components tends to decrease accordingly.Also, the absolute amount of distillate or reflux liquid is reliably grasped every time to control batch filling distillation. However, there is a problem that the operability of batch filling distillation is poor.

The present invention has been made to solve the above-mentioned conventional problems, and as a result of intensive studies, it has been found that the relative volatility is small.
Using a batch packed distillation column with a high number of theoretical plates from a distillation stock solution that is difficult to separate, effectively utilizing the separation performance of the distillation column, and efficiently collecting high-purity products in high yield. It was found and completed. The present invention changes the reflux ratio so that the instantaneous minimum theoretical number of steps is always kept constant from the start to the end of batch-packing distillation, thereby making the most of the performance of the batch-packing distillation apparatus, and performing enormous repetitive calculations. The present invention provides a batch-packing distillation method capable of performing batch-packing distillation efficiently and economically without the need for a batch-packing distillation, and performs a batch-packing distillation of a distillation stock solution under conditions where the separation performance is optimized extremely efficiently. A batch-packing distillation apparatus capable of accurately grasping the absolute amounts of distillate and reflux liquid necessary for controlling the batch-packing distillation column and appropriately controlling the batch-packing distillation to improve the recovery rate. The purpose is to provide.

[0008]

In order to achieve the above object, the present invention has the following arrangement. Claim 1 of the present invention
The batch filling distillation method described in the above, a distillation stock solution containing a low boiling point light key component and a high boiling point heavy key component is subjected to a reflux operation using a batch packed distillation column, while distillate and kettle at a predetermined recovery rate respectively A batch packed distillation method for separating into a residual liquid, wherein the minimum number of theoretical steps S defined by (Equation 1)
_While using a batch packed distillation column having a theoretical plate number N greater than _m- 1, and adjusting the reflux ratio in the reflux operation,
Distillation is performed so that the instantaneous minimum theoretical step number S _M defined by (Equation 2) matches the minimum theoretical step number S _m . _{S m = ln (ln (1} -η1) / ln (1-η2)) / lnα ---- ( Equation 1) (wherein, .eta.1 the recovery of the distillate right key components, .eta.2
Represents the recovery rate of the heavy key component in the distillate, and α represents the relative volatility of the light key component to the heavy key component. ) S _M = ln ((xD1 / xD2) / (xB1 / xB2)) / lnα (Formula 2) where xD1 is the instantaneous distilling composition of the light key component, xD2
Represents the instantaneous distillation composition of the heavy key component, xB1 represents the instantaneous residue composition of the light key component, and xB2 represents the instantaneous residue composition of the heavy key component. With this configuration, the following operation is obtained. (A) From a distillation stock solution having a small specific volatility and difficult to separate,
Using a batch packed distillation column with a high number of theoretical plates, making effective use of the separation performance of the distillation column, efficiently recovering high-purity products in high yields and obtaining products at low cost Can be. (B) The mechanism of the operation is clear, and the composition change during the distillation can be sequentially grasped by calculation. Therefore, it is possible to appropriately cope with the fluctuation during the operation only by adjusting the reflux ratio. (C) by adjusting the reflux ratio (Equation 2) is the instantaneous constantly minimum theoretical number of steps S _M as defined in (Equation 1)
In to match the minimum theoretical number of steps S _m which is defined, i.e., since in order to maintain the state of the batch packed distillation corresponding to the number of theoretical plates constant total reflux distillation, the equilibrium relationship between the components in each theoretical plate Is properly maintained, and the batch filling distillation of the distillation stock solution can be efficiently performed. (D) The operation pattern of the reflux ratio from the start to the end of batch-packing distillation is defined as the instantaneous minimum theoretical step number S during this period.
_Batch filling distillation operation can be performed according to this pattern in advance so that _M becomes a predetermined value, so that batch filling distillation operation can be performed appropriately and reliably without directly measuring the temperature, pressure, etc. of the distillation stock solution. To obtain a distillate having a predetermined recovery rate and a predetermined purity or a bottom liquid. (E) The reflux ratio can be set corresponding to the instantaneous minimum theoretical step number S _M simply by determining the minimum theoretical step number S _m that is the target value. , And batch batch distillation of the distillation stock solution can be performed efficiently and economically under conditions where the separation conditions are optimized. (F) the minimum theoretical number of steps S _m is, .eta.1, .eta.2, because it is set only 3 variables alpha, the set easily target value without requiring complicated iterative calculations, adjusted reflux ratio accordingly It can be done efficiently. (G) The batch packed distillation column is increased from the minimum theoretical step number _Sm to 1
The subtracted value, i.e., because it has a large number of theoretical plates N than the minimum number of theoretical plates N _m, times with a margin operations reflux ratio control in packed distillation column, and reliably can be performed, the batch packed distillation productivity Can be increased. (H) Since a batch packed distillation column having a theoretical plate number N larger than the minimum theoretical step number S _m -1 is used, stable operating conditions can be easily secured, and the operation can be performed under a condition having a sufficient space. Separation can be performed efficiently. (I) Number of theoretical plates N = 50, charge composition xF = 0.5, specific volatility α = 1.273, average distillate composition xDav = 0.99
5. When the recovery η = 0.90, the newly developed batch distillation method is about 1 /
A distillation time of 2 is sufficient, and productivity can be significantly increased.

Here, the theoretical number N of batch packed distillation columns is as follows:
HETP (filling per theoretical plate)
Height) and the filling height. Necessary for separation
The number of theoretical steps (= the number of theoretical stages N + 1) is
Number S _m1.3 to 2.7 times the economically appropriate range
It is desirable to select. Here, the light key component and
The beak component is calculated by the formula (1) in the aforementioned reference 1 (p. 512).
Means the components for separation purposes as defined in Many
In the case of component systems, low
A component with a boiling point and a component with a higher boiling point
Corresponds to low-boiling components and high-boiling components, respectively.
are doing. The reflux ratio is provided at the top of the batch packed distillation column.
Packed distillation column with condensate from the condenser
Reflux and reflux distillation from batch packed distillation tower
By operating the reflux mechanism that distributes liquid and
Can be set to the value of

[0010] (Equation 2) is expressed by Fenske
e) is a relational equation known as the equation of (e), which defines the relationship between the instantaneous bottom composition and the instantaneous distillate composition during the distillation, whereby the distillation at each time point from the start to the end of the batch filling distillation operation is defined. The separation performance of the stock solution can be evaluated. (Equation 1) is calculated by integrating the minimum theoretical step number S _m obtained by integrating the recovery rate from the start of distillation to the end point of distillation when the instantaneous minimum theoretical step number S _M obtained by (Equation 2) is operated. This is a prescribed expression.
That is, it can be obtained by integrating from the Fenske equation using the Rayleigh equation which is a calculation equation for batch filling distillation. This (Formula 1) is described in the literature (Kojima, Aoyama: Chemical Engineering, 23, No. 6, p21 (19)
59)) is derived as a formula for calculating the minimum theoretical plate number.
Minimum theoretical number of steps S _m which is defined by (Equation 1), the constants as a target value of the instantaneous minimum theoretical number of steps S _M, refluxed for minimum theoretical number of steps S _M instantaneously to meet the target value By controlling the ratio, the distillation stock solution having a component that can be regarded as being substantially constant with a specific volatility and having a predetermined component composition, and a distillate having a predetermined recovery rate and purity at the end point of the batch filling distillation, respectively. It can be most economically and efficiently separated from the bottom liquid.

[0011] In the batch packed distillation method according to the present invention, the distillation stock solution containing a low boiling point light key component and a high boiling point heavy key component is subjected to a reflux operation using a batch packed distillation column at a predetermined recovery rate. A batch packed distillation method for separating into a distillate and a bottom residue in the batch packed distillation method having a theoretical plate number N larger than the minimum theoretical step number S _m -1 in the batch packed distillation method according to claim 1. A column is used, and the reflux ratio in the reflux operation is not less than the reflux ratio necessary to maintain the instantaneous minimum theoretical step number S _M in the batch packed distillation method according to claim 1 at the minimum theoretical step number S _m . It is configured to distill at a set value. This configuration has the following operation. (A) The instantaneous minimum theoretical step number S for representing the distillation state
Together defined by the _M (Equation 2), that the target minimum theoretical number of steps value to become S _m, a distillation stock solution having a predetermined component configuration, having a respective predetermined recovery and purity at the end of the batch packed distillation Since the distillate and the bottom liquid can be most efficiently separated (formula 1), the reflux ratio can be adjusted to a predetermined range by using this to optimize the separation performance. The batch filling distillation operation can be appropriately and efficiently performed under the conditions. (B) Since the actual reflux ratio is set within a range not less than the reflux ratio required to maintain the instantaneous minimum theoretical step number S _M at the minimum theoretical step number S _m , the reflux ratio is controlled with a sufficient margin. can do. (C) Since a necessary change pattern of the appropriate reflux ratio can be determined in advance and the reflux ratio can be changed stepwise within a range not less than the appropriate reflux ratio, the occurrence of a pinch point can be avoided and the reflux ratio can be reduced. The operation can be easily performed. (D) By incorporating the constant reflux ratio operation, the distillation time is slightly longer than in the case where the reflux ratio is continuously changed, but the operation is easy and stable operation is possible.

According to a third aspect of the present invention, there is provided the batch packed distillation method according to the first or second aspect, wherein the number S of theoretical steps of the batch packed distillation column is 1.3 S _m ≦ S ≦ 2.7 S _m . It is configured to be controlled so as to satisfy the conditions. With this configuration, the following operation can be obtained in addition to the operation obtained in claim 1 or 2. Since the theoretical number of steps S plus number 1 of the distillation kettle theoretical plate number N of (a) batch packed distillation column is limited to a specific range for the minimum theoretical step number S _m, more efficiently batch packed distillation operation And the recovery rate can be improved. (B) Since S / S _m is selected in an appropriate range, an economical batch-packing distillation operation with a good recovery rate can be performed. (C) Since S / S _m is selected in an appropriate range, an economically appropriate batch packed distillation column can be designed. Here, the theoretical number of steps S is less than the 1.3 times the minimum theoretical step number S _m, is less margin necessary to control the instantaneous minimum theoretical number of steps S _M by varying the reflux ratio This is not preferable because the control operation of the batch packed distillation column tends to be difficult. Conversely, when the theoretical number of steps S exceeds the 2.7 times the minimum theoretical step number S _m,
It is not preferable because the equipment cost required to increase the number N of theoretical plates increases, and the separation performance of the distillation stock solution cannot be improved so much.

[0013] The batch-packed distillation apparatus according to claim 4 comprises:
(A) a distillation still into which a stock solution containing a low-boiling light key component and a high-boiling heavy key component is charged; (b) a reboiler for circulating and heating the distillation stock in the still;
A batch packed distillation column in which the steam generated by heating by the reboiler is passed and a packing is disposed, (d) a condenser for condensing a fraction distilled from the top of the batch packed distillation column, and (e) the condenser A reflux mechanism having a control valve for distributing the distillate condensed in the distillate discharged to the distillate receiver and the reflux liquid returned to the batch packed distillation column at a predetermined reflux ratio; A liquid level meter provided in the distillate receiver for detecting the liquid level and / or a weight meter for detecting the weight thereof; and (g) the magnitude of the separation performance during batch packed distillation by operating the reflux mechanism. And the reflux ratio is adjusted so that the instantaneous minimum theoretical step number S _M becomes a predetermined target value, and data obtained by the liquid level meter or the weighing scale is compared with target data set in advance to perform batch measurement. Monitoring of packed distillation and said It is constituted by a control unit for controlling the flow mechanism. With this configuration, the following operation is obtained. (A) Using a batch packed distillation column with a high number of theoretical plates from a distillation stock solution having a small specific volatility and difficult to separate, effectively utilizing the separation performance of the distillation column to efficiently produce high-purity products. It can be recovered in a yield, and is excellent in energy saving and productivity. (B) Since there is provided a control unit for adjusting the reflux ratio during batch packed distillation so that the instantaneous minimum theoretical step number becomes a predetermined target value, the state of batch packed distillation corresponding to total reflux distillation with a fixed number of theoretical stages , And the batch filling distillation of the distillation stock solution can be efficiently performed. (C) Since the control unit for monitoring the batch filling distillation operation by comparing the data acquired by the liquid level meter or the weighing scale with the preset target data is provided, the temperature and pressure of the undistilled solution are directly measured. It is possible to monitor the operation of batch-packing distillation appropriately and reliably without obtaining a distillate or a bottom residue having a predetermined recovery rate and a predetermined purity. (D) The reflux ratio can be set corresponding to the target value (minimum theoretical step number S _m ) of the instantaneous minimum theoretical step number S _M by simply determining the target value. It is possible to efficiently and economically perform batch-packed distillation of the distillation stock under the appropriate conditions under which the number of theoretical plates is constant. (E) In the case where the batch packing distillation column is filled with the regular packing, each of the voids formed by the regular packings is stably and uniformly secured as a flow path for the vapor and the reflux liquid by each of them. The amount of liquid (hold-up) staying in the stage can be reduced to maintain the gas-liquid equilibrium relationship properly, and the result can be applied assuming that there is no hold-up, and the calculation can be simplified. .

Here, a knock-back type capacitor or the like can be used as the capacitor. When a normal condenser installed outside the distillation column is used, the packed column cannot be operated efficiently because the condensate is supercooled below the boiling point. In this case, by providing a preheater in the reflux line and heating it to near the boiling point, an effect equivalent to a knockback type installed at the top of the distillation column can be obtained.
The reboiler is of the type normally used, except for performing vacuum distillation in which the rise in boiling point is a problem, a liquid-filled external circulation type, a jacket type, a thermosiphon reboiler,
A kettle-type reboiler or the like can be used. In the case of a jacket type reboiler, if the liquid level decreases, the heat transfer area becomes insufficient and the evaporation rate decreases.However, in a distillation method that operates with a constant evaporation amount, an external circulation type reboiler is effective. It is. Batch distillation often requires a vacuum distillation operation, and a liquid film falling reboiler can be applied to such a vacuum distillation. The reflux mechanism distributes the condensed liquid discharged from the condenser and the like to the reflux liquid and the distillate at a predetermined reflux ratio, and is composed of a piping system having a plurality of control valves for the flow rate. Are controlled via the control unit.

The liquid level gauges provided on the distillate receiver and the distillation still are provided for accurately grasping the liquid level (liquid amount), and detect the position of the float floating on the liquid surface. A float type, a method of detecting the liquid level with a U-shaped tube installed on the outer side surface, or a sound wave type of detecting the distance to the liquid surface by sound waves reflected from the liquid surface can be used. As a weighing device provided in the distillate receiver and the distillation still, one using a load cell or the like can be applied. It is effective to install a liquid level gauge or a weighing scale in order to grasp the amount of liquid in the still and the distillate receiver. The control unit is
A device for operating the recirculation system comprising a computer and a sequencer or the like, batch filling minimum theoretical number of steps S _M moment in the distillation of the by such a reflux ratio maintained at a predetermined target value (minimum theoretical number of steps S _m) A change pattern can be obtained in advance, and the reflux ratio can be controlled according to the change pattern. The program is programmed to compare the data acquired by the liquid level meter or the weighing scale with preset target data of the liquid level change and the weight change to monitor the batch filling distillation operation.

In the batch packed distillation apparatus according to a fifth aspect, in the batch packed distillation apparatus according to the fourth aspect, the number of theoretical steps S obtained by adding 1 to the number of theoretical plates in the batch packed distillation column and 1 to the number of distillation tanks is obtained. , when the minimum theoretical number of steps in has been batch packed distillation method according to claim 1 and a S _m, the number of steps S is controlled to satisfy the condition of 1.3S _m ≦ S ≦ 2.7S _m control Unit. With this configuration, the following operation is obtained in addition to the operation described in claim 4. Since the theoretical number of steps S plus number 1 of the distillation kettle theoretical plate number N of (a) batch packed distillation column is limited to a specific range for the minimum theoretical step number S _m, more efficiently batch packed distillation operation And the recovery rate can be improved. (B) Since S / _Sm is selected in an appropriate range, an economical batch-packing distillation operation with good recovery can be performed. (C) Since S / S _m is selected in an appropriate range, an economically appropriate batch packed distillation column can be designed. Here, the theoretical number of steps S is less than the 1.3 times the minimum theoretical step number S _m, afford less batch filling required to control the operation of the change is allowed by batch packed distillation reflux ratio distilling It is not preferable because the control operation of the tower tends to be difficult. Improve the contrary the theory step number S is greater than the 2.7 times the minimum theoretical step number S _m, on equipment cost required to increase the number of theoretical plates N increases, the separation performance of less distillation stock solution It is not preferable because it cannot be performed.

According to a sixth aspect of the present invention, there is provided the batch packed distillation apparatus according to the fourth or fifth aspect, wherein the batch packed distillation column comprises at least one of a metal plate, a wire mesh type, and a grid type. Is provided in the tower. This configuration has the following effect in addition to the effect of the sixth aspect. (A) Since the batch packing distillation column is filled with the structured packing, a flow path for vapor or reflux liquid is formed between the structured packings or in pores or depressions formed in the structured packing, Stable and uniform mass transfer can be ensured in the batch packed distillation column. (B) The amount of liquid accumulated and retained in each stage of the batch packed distillation column (hold-up) can be reduced, and the gas-liquid equilibrium relationship can be effectively maintained. (C) The result assuming that there is no hold-up can be applied, and the calculation can be performed easily. (D) Since the gas-liquid contacting efficiency is better than the case where the random packing is used, the effective height of the batch packed distillation column can be reduced, and a batch packed distillation column with high efficiency and low cost can be designed. (E) Since the reflux liquid is less likely to accumulate between the structured packing and the structured packing, the residence time of the reflux liquid in the column can be shortened. Here, the ordered packing is made of a metal such as stainless steel, titanium, zirconium, nickel, or an alloy thereof, or a sheet-type metal plate type having a large number of pores, or a thin metal wire. A mesh type metal plate type or a grid type formed by knitting in a net shape. These structured packings are used in a state of being stacked in a batch packed distillation column.

According to a seventh aspect of the present invention, there is provided a batch-packing distillation apparatus according to any one of the fourth to sixth aspects, wherein the condenser is a knock-back type condenser. With this configuration, the following operation is obtained in addition to the effect of any one of the fourth to sixth aspects. (A) Since a low-temperature condensate is directly heat-exchanged with inlet steam because of having a knock-back type condenser, heat transfer efficiency is good and a reflux temperature close to the boiling point can be secured. (B) Since the knockback type condenser is installed at the top of the distillation column, the reflux operation can be performed by using gravity without using a reflux pump.

The batch filling distillation apparatus according to claim 8 is the invention according to any one of claims 4 to 7, wherein the reboiler is formed by an external circulation liquid film flow-down system. With this configuration, the following operation is obtained in addition to the effect of any one of the fourth to seventh aspects. (A) It is most suitable for distillation in which the operation is performed while keeping the vapor amount constant, and is particularly suitable for batch packed distillation in which vacuum distillation is often required.

[0020]

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings. The batch-packing distillation method and the batch-packing distillation apparatus of the first embodiment are based on the idea of the reflux policy of performing the reflux operation while maximizing the performance of the distillation column. The optimization method shown is different in the applied theoretical formula, device form, implementation conditions, and the like. That is,
The batch packed distillation method according to the first embodiment seeks a method for always maintaining the efficiency of the batch packed distillation column efficiently in the batch packed distillation operation, and defines the minimum theoretical number of steps.
Separation performance in distillation (xD1 / xD2) / (xB1 / x
B2) The instantaneous minimum theoretical step number S _M (S
_M = ln ((xD1 / xD2) / (xB1 / xB2)) / l
nα, where xD1 represents the instantaneous distillation composition of the light key component, xD2 represents the instantaneous distillation composition of the heavy key component, xB1 represents the instantaneous residue composition of the light key component, and xB2 represents the instantaneous residue composition of the heavy key component. ), And those obtained by changing the reflux ratio R to match the minimum theoretical number of steps S _m. Note that the minimum theoretical stage number N _m is given by N _m = S _m −1.

Conventionally, reference 4 (Robinson, C .;
S. and Gilliland, E .; R. : "Ele
Ments of Fractional Disti
lation ", p376 (1950)) and Reference 5
(Mitsuho Hirata, Masahiro Yorimi: "Distillation Engineering Handbook" p
214, Asakura Shoten (1966)), it has been considered impossible to realize an ideal state in total reflux distillation with a fixed number of theoretical plates by batch packed distillation. The method of the first embodiment is a batch-packing distillation method in which the reflux ratio is changed so as to always maintain an ideal state corresponding to the total reflux distillation at a constant theoretical plate number.

FIG. 1 is a block diagram of a batch packed distillation apparatus to which the batch packed distillation method of the first embodiment is applied. In FIG. 1, reference numeral 10 denotes a batch-packing distillation apparatus to which the batch-packing distillation method of the first embodiment is applied, 11 denotes a distillation still into which a distilling solution containing a low-boiling light key component and a high-boiling heavy key component is put, and 12 denotes a distillation. A batch packed distillation column, which is disposed at the top of the kettle and is supplied with vapor from the distillation pot 11 from the bottom and which is condensed by regular packing and the like held inside, is returned to the distillation pot 11. Is a knock-back type condenser disposed at the upper part of the batch distillation distillation column 1 for distributing the condensate cooled by the knock-back type condenser 13.
A control valve for a reflux liquid provided on a pipe for refluxing to 2, a control valve for a distillate provided on a pipe for removing a part of the condensate of the condenser 13 as a distillate;
16 is a distillate receiver to which distillate is supplied via a distillate control valve 15; 17 is a liquid film falling reboiler for heating the distillation stock solution in the distillation still 11 using heated steam; Reference numeral 18 denotes a circulation pump for circulating the undistilled solution between the liquid film falling reboiler 17 and the evaporator 11, 19 a vent condenser for cooling excess gas from the knockback condenser 13 and discharging the gas to the outside, and 20 a condenser. A liquid level meter for detecting the liquid level in the evaporator 11 and the distillate receiver 16;
Reference numeral 1 denotes a weighing scale for detecting the weight of the evaporator 11 and the distillate receiver 16, and reference numeral 22 denotes a packed bed of sheet-type regular packing.

The batch filling distillation apparatus 10 according to the first embodiment
The main constituents are: 1) a batch packed distillation column 12 filled with an ordered packing and having a predetermined number of theoretical plates, 2) a knockback condenser 13, 3) a liquid film falling reboiler 17, and 4) distillation. It has a liquid level meter 20 or a weighing scale 21 for detecting the liquid volume of the kettle 11 and the distillate receiver 16, and 5) a control unit. have.

1) Batch packed distillation column Batch packed distillation column 12 has a theoretical plate number of packed column height H
And HETP (filling height per theoretical plate) indicating the performance of the packing. The batch packed distillation column 12 is provided with a mesh-type regular packing having a large number of pores formed therein and an irregular packing having a ring shape or a cylindrical shape. Through the holes, the steam and reflux liquid in the still are transferred by heat or mass.
In the case of performing batch filling distillation operation, if there is an influence of hold-up, the behavior of batch filling distillation becomes complicated, and it is necessary to grasp the behavior using a complicated calculation method. When the hold-up is small, the result calculated on the assumption that there is no hold-up and the exact solution almost agree with each other in Reference 6 (supervised by Kunio Nagahama: High Purification Technology System "Vol.2 Separation Technology" p194, Fuji Techno System (1997)). By using a batch packed distillation column packed with a high-performance structured packing that reduces the hold-up, as a result of intensive studies, the hold-up was ignored,
It has been found that the basic conditions can be easily calculated on the assumption that the relative volatility is constant and the rising steam flow rate is constant. In addition, in the case of using the structured packing, the gas-liquid contact efficiency can be improved as compared with the case of using the random packing. It has been found that a batch packed distillation column can be designed, the apparatus can be made compact, and heat energy can be saved. Furthermore, even under the condition where a high number of stages is required, the packing height of the batch packed distillation column can be set low by adopting a high-performance packing, so that the implementation becomes possible. The theoretical plate number N of the batch packed distillation column 12 is a unique value determined from the equipment specifications and the like, and is a number of plates sufficiently larger than the minimum theoretical step number S _m -1 determined by the distillation stock solution and the target recovery rate. Is used. As a result, the operation of controlling the reflux ratio in the batch packed distillation column 12 can be performed with sufficient margin and reliably.

2) Knockback type condenser The knockback type condenser 13 is a batch packed distillation column 12.
Is a condenser that condenses the vapor of the undistilled liquid discharged from the top of the column on the surface of the heat transfer tube, and brings the condensate into AC contact with the inlet vapor. This allows the supercooled condensate to undergo heat transfer and heat exchange with the high-temperature inlet vapor, thereby maintaining the temperature of the condensate near the boiling point. Further, by using the batch packed distillation column 12 filled with the ordered packing with little hold-up and the knock-back type condenser 13 at a temperature close to the boiling point while suppressing a decrease in separation performance due to uneven diffusion flow rate. To perform a reflux operation.
In the case of a batch packed column using ordered packing with little hold-up, if the temperature of the reflux liquid is lower than the boiling point, sufficient residence time until boiling can not be obtained, so the diffusion flow rate in the column becomes uneven and separation occurs. Performance decreases. However, if a knock-back type condenser in which the liquid condensed on the surface of the heat transfer tube falls directly in contact with the rising inlet steam and falls, the reflux operation can be performed at a temperature close to the boiling point.

3) Liquid film falling type reboiler The liquid film falling type reboiler 17 is a multi-tube heat exchanger having a number of vertical heat transfer tubes built in the upper part of the still and a multi-tube heat exchanger. A circulating pump for supplying to the upper part of the heat exchanger;
A steam pipe for supplying steam to the heat transfer tube for evaporating the circulating liquid flowing down in the form of a liquid film by gravity on the surface of the heat transfer tube is provided. The jacket type reboiler has the disadvantage that the heat transfer area becomes insufficient and the evaporation rate decreases as the liquid level decreases.However, during distillation in which the evaporation amount is kept constant, the external circulation type liquid is used. The membrane falling reboiler 17 is effective because it does not have such disadvantages. In addition, a batch distillation often requires a vacuum distillation operation, and a liquid film falling reboiler has a wide evaporation surface even in the case of vacuum distillation, which is advantageous.

4) Level gauge or weighing gauge Level gauge 20 provided in the evaporator 11 and the distillate receiver 16
Alternatively, the weighing scale 21 is a device capable of acquiring the liquid volume of the distillation still 11 and the distillate receiver 16 in real time, and the data of the liquid volume is obtained together with the heat, pressure, temperature, flow rate, etc. of other parts. Input to the control unit.

5) Control Unit The opening of each of the reflux liquid control valve 14 and the distillate control valve 15 is controlled via a control unit (not shown), whereby the reflux ratio R is set to a predetermined value. be able to. In order to obtain a distillate of the target concentration at a predetermined recovery rate, after performing a total reflux operation in advance to make the rising evaporation flow rate constant, calculate the distillate amount theoretically required with respect to the distillation time. do it,
It is necessary to control the change in the reflux ratio during the distillation so as to maintain the liquid amount in the distillate receiver 16 at or below the theoretical value. At this time, by using the liquid level meter 20 and the weighing scale 21, each liquid amount in the batch filling distillation process can be directly grasped, and this management and control can be performed accurately. The control unit can monitor the batch filling distillation operation by comparing these values with target data calculated in advance, and is set in advance so that a distillate having a predetermined recovery rate can be efficiently obtained. According to the change pattern of the reflux ratio, the reflux mechanism including the reflux control valve 14 and the distillate control valve 15 is controlled.

Next, a method of setting the reflux ratio in the batch filling distillation method according to the first embodiment will be described. In order to calculate the reflux ratio for keeping the instantaneous minimum theoretical step number S _M in the batch packed distillation at a predetermined value, 1) a sequential stage calculation method,
2) A new logical expression was created using the shortcut method, and the optimum reflux ratio was easily obtained. Hereinafter, these methods will be described.

1) Sequential-stage calculation method In the sequential-stage calculation method, the number of theoretical steps S and the minimum number of theoretical steps S are calculated for each residue composition from the start of distillation to the end point of distillation.
_This is a method for obtaining a reflux ratio R that satisfies _m simultaneously. Here, a McCabe-Thie (McCabe-Thie) in which the enthalpy and latent heat of vaporization of the liquid are constant regardless of the components.
le) An operation line is determined based on the assumption of the method, and the number of theoretical steps is obtained by sequentially calculating the operation line in a stepwise manner. The sequential stage calculation method is a calculation method in which a sequential calculation is performed using an equation of an operation line derived from a material balance and an equation of an equilibrium relationship, and has a feature that a gas-liquid composition of each stage can be accurately obtained. That is, the reflux ratio that makes the instantaneous minimum theoretical step number S _M equal to the minimum theoretical step number S _m is obtained by the following procedures (1) to (4). First, the recovery ratios η1 and η2 of the light key component and the heavy key component in the distillate and the value of the relative volatility α of the light key component with respect to the heavy key component are substituted into (Equation 1) to obtain the minimum theoretical step number S _m. Ask for. The number N of theoretical plates of the distillation column used for actual separation is selected. The theoretical plate number N sets a theoretical plate number N larger than S _m −1. Number of theoretical plates N already used for separation (N> S _m -1)
Is determined, the theoretical step number S is determined as S = N + 1. There are many times packed distillation column to the factory, when choosing a suitable distillation column, the ratio between the theoretical number of steps S and minimum theoretical number of steps S _m (S / S _m) is 1.3 ≦ S / S _m Select a distillation column in the range of ≦ 2.7.
When designing a new suitable distillation column, the following FIG.
As described in 3, the optimal number of theoretical steps S is S / S _m =
2 and when there is no restriction on the installation conditions, S /
It is recommended to design with S _m = 2. Here, for the sake of explanation, the number of theoretical steps S (= N + 1) is a value of S _m × 2. The number N of theoretical stages is a value (S-1) obtained by subtracting 1 from the number S of theoretical steps. For the instantaneous pot remaining composition xB, the instantaneous minimum theoretical step number S _M of (Equation 2) is replaced by the minimum theoretical step number S _m of (Equation 1).
By substituting the values, alpha, xB, instantaneous distillate composition xD from S _m
Ask for. From the calculated distillate composition xD to the remaining tank composition xB
The recirculation ratio is changed to calculate successive stages, and a recirculation ratio is calculated such that the number of theoretical steps S obtained by adding 1 to the number N of theoretical stages set in the step is equal to S _m × 2. This reflux ratio is the reflux ratio with respect to the instant kettle composition xB.

2) Shortcut method The shortcut method is a method of Fenske.
Equation, Gillian's correlation equation, Anne
Using the three equations of the Underwood equation
This is a calculation method for obtaining the reflux ratio. Here, we'll start the distillation
Number of theoretical steps for each pot residue composition up to the end of distillation
S and minimum number of theoretical steps S_mSatisfy the three equations at the same time
Such a reflux ratio can be short-circuited without performing successive-stage calculations.
Statistically more than in many cases
It is obtained by using the obtained Gililand correlation equation. Concrete
In general, the reflux ratio that meets the conditions is determined by the following procedure
Can be That is, in this shortcut method,
Number of small theoretical steps S_mIs calculated. Next, S_mMore than -1
The number of theoretical steps N (= N
+1) is calculated. Next, the minimum reflux ratio R_m, Minimum number of theoretical steps S_mAnd the real
Used in a batch packed distillation column
Using the Gililand's correlation formula that holds between the flow ratio R,
That is, (R−R) obtained statistically_m) / (R + 1)
(SS_m) / (S + 1), the expression (S−
S_m) / (S + 1)_m) / (R + 1)
Find the value of Here, without performing the sequential calculation,
Number of theoretical steps S, minimum number of theoretical steps S_m, Reflux ratio
R, minimum reflux ratio R_mGililand correlation that defines the relationship
The formula is applied. The reflux ratio R is calculated by the minimum reflux ratio R according to the underwood equation.
_mIs determined. Minimum reflux ratio R_mIs under
In the Wood's equation, the instantaneous distillate composition xD and instantaneous pot remaining composition xB
By substituting the value, the minimum reflux ratio R_mIs required. Where
The formula of Underwood is constant component volatility,
Of the composition distribution in the column derived under the assumption of equimolar liquid flow
From the analysis expression, specify the minimum specification for separation specifications and infinite number of stages.
This is a formula for calculating a reflux ratio in a reflux state, and specifically,
Is R _m+ 1 = Σαi · xDi / (αi-λk)
Notation. Where the symbol Σ represents the sum over i = 1 to k
Where α is the relative volatility for any reference component and λk is the
Equation relating to the number z (Σ (αi · zi / (αi−λ))
= 1-q, where Σ is the sum over i = 1 to the total number of components, q
Represents a constant determined by the thermal conditions of the raw material. Α in the root of
h (high boiling point component) <λk <αl (low boiling point component)
I am satisfied. Where R is the reflux ratio, R_mIs the smallest
Reflux ratio, S is the number of steps, S_mIs the minimum number of steps
You.

Reference 7 (Logsdon, J.S., Diw
ekar, U.S.A. M and Biegler, L .; T:
Trans IChemE, 68, p434 (199
The method of obtaining the reflux ratio shown in 0))) is a calculation method of an optimization method using a shortcut, but unlike this embodiment, it requires a large number of conditions such as cost data to be set, and the profit function An enormous amount of calculation is required to maximize the (objective function). On the other hand, in the present embodiment, the method is based on a clear reflux policy of keeping the minimum number of theoretical steps S _m obtained from the separation condition constant, and the calculation procedure can be simplified, and the calculation can be performed quickly and accurately. It can be performed. The optimal distillation time (optimal distillation time expressed by the actual consumption time) shown in Reference 7 of the optimization using the shortcut method and the distillation time obtained by the shortcut method of the present embodiment are in good agreement. I have. Note that the shortcut method can be used even when the distillation stock solution has multiple components. That is, the present invention can be applied to a case where a light key component in a multicomponent distillation stock solution is separated as a main fraction,
The reflux ratio can be determined from the Gililand correlation and the Underwood equation.

3) Comparison of the results by the sequential calculation method and the shortcut method Reference 8 (Kerkhof, LHJ and Vis)
sers, H .; J. M: ChemEng. Sci, 3
3, p961 (1978)), while the distillation time in the example using the sequential calculation method is 3.35 Hr, whereas the distillation time in Reference 7 using the shortcut method is 3.63 Hr.
r. The value obtained by the shortcut method in the present embodiment is 3.61Hr. Thus, the short-cut method has a slightly higher reflux ratio and a longer distillation time than the sequential-stage calculation method. Therefore, it is desirable to selectively use the shortcut method and the sequential calculation method according to the purpose of pursuing the shortest distillation time or considering a distillation operation with a margin.

Hereinafter, a batch filling distillation method of the present embodiment applied to the batch filling distillation apparatus 10 will be described.
First, a distillation stock solution containing predetermined amounts of a light key component and a heavy key component is charged into a still 11, and the liquid film falling reboiler 1 is charged.
7 and the circulation pump 18 are operated to heat the distillation stock solution for a predetermined period of time, to make it steady, to set an appropriate rising steam flow rate for the column diameter of the batch packed distillation column 12, and to set a steady state in which the rising steam flow rate becomes constant. Let it be maintained. Next, the distillate containing the light key component as a main component is distilled from the knock-back type condenser 13 by changing the reflux ratio R in a predetermined pattern using the control unit in accordance with the distillation time and the distillation rate. Liquid receiver 16
Next, a batch filling distillation operation of recovering the bottom liquid containing a heavy key component as a main component in the evaporating tank 11 is performed.

In evaluating the results of the batch-packing distillation method, reference was made to the aforementioned reference 8 which describes a method for optimizing batch-packing distillation. Here, Table 1 shows Reference 8.
Are data showing examples of separation conditions in Cases 1 to 24 and the embodiment. Table 2 shows Tinτ0 (optimum distillation time T (unit: Hr)
And τ0 (unit: Hr) and data of S _m and S / S _m . The optimum distillation time T is a time value (unit: Hr) defined as T = total vapor amount / rising vapor flow rate, and τ0 is the amount of the undistilled stock solution put into the distillation still ascending in the batch packed distillation column. It is a time value (unit: Hr) divided by the rising steam flow rate of steam. Based on the separation conditions in Case 24 of Document 8 to which the sequential calculation method shown in Tables 1 and 2 was applied, the required steam amount (from the distillation start point to the distillation end point) in the batch packed distillation method of the present embodiment. The ratio (A / B) of the total vapor amount A to the charged amount B of the undistilled solution in the evaporator was determined. Then, the required steam amount, that is, T of the literature value 8 optimized by using Tinτ0 and Pontryagin's maximum principle
inτ0. In addition, results of studies on other cases 1 to 23 of Table 1 having different separation conditions will be described.

[0036]

[Table 1]

[0037]

[Table 2]

The separation conditions for batch packed distillation in Case 24 in Tables 1 and 2 are as follows: number of theoretical steps S = 21, specific evaporation degree α = 1.3, charge composition xF = 0.5, average distillate composition xDav = 0.98, light key component recovery rate η1 =
0.7281, charge amount 100 kmol, rising steam flow rate 1
20 kmol / Hr, recovery rate of heavy key component η2 = η
1 × (xF / (1-xF)) × ((1-xDav) / x
Dav) = 0.01486, minimum number of theoretical steps S _m =
ln (ln (1-0.7281) / ln (1-0.01
486)) / ln1.3 = 17.01.

In the first embodiment, the same separation conditions as those in Reference 8 are set, and the time from the start to the end of batch-packing distillation after reaching the steady state by performing the total reflux operation is divided into 10 sections. I went. Then, set by applying Equation 1, right key component and Hebiki component respectively recovery η1 mutual relative volatility is alpha, the minimum theoretical step number S _m to obtain at η2 to 17.01 . next,
Instantaneous minimum theoretical step number S defined by (Equation 2)
_M is the minimum theoretical step number S _m ((1
7.01), the reflux ratio and the instantaneous distillate composition were determined from the instant kettle composition xB of the light key component and the heavy key component in each section by using the successive calculation method of McCabe Seal. Based on this value, numerical integration of each section was performed, and the distillation rate, the required steam amount, and the distillation time were determined. The results are shown in Table 3. Table 3 shows the bottom composition (unit: dimensionless), reflux ratio (unit: dimensionless), distillation rate (unit: dimensionless), required steam amount (unit: dimensionless), and distillation time (unit). :
Hr), xD (unit: dimensionless), S _M (unit: dimensionless)
Are listed. FIG. 2 shows a comparison between the change in the reflux ratio (solid line) obtained by the batch filling distillation method of the present embodiment and the change in the reflux ratio (broken line) shown in Reference 8.

[0040]

[Table 3]

The method of batch packed distillation first embodiment, the constant number of theoretical plates, such as are described in the literature 8 and the conventional method that substantially changes, the optimum value the minimum theoretical number of steps S _M moment They differ in that they are retained. In the present embodiment, since the operation with good separation efficiency is performed so that the minimum number of theoretical steps _Sm is constant even in the initial stage of distillation in which the concentration of the light key component in the bottom composition is high, the reflux ratio is large and the average for the purpose of separation is large. A much higher concentration of distillate composition is obtained than the distillate composition. Therefore, since a high concentration of distillate is accumulated in the distillate receiver, it is possible to cope with slight fluctuations during the distillation. In addition, since the operation is performed so that the minimum theoretical number of steps _Sm is constant, there is an advantage that the change in operating conditions is small, the change in the reflux ratio is small compared to the optimization method, and the operation of the batch packed distillation column becomes easy. are doing. On the other hand, in the optimization method, the optimum value is aimed at even at the beginning of distillation, so that the reflux ratio is small and the conditions as close as possible to the average distillate composition are aimed.
Therefore, the operation tends to be weak against the fluctuation. That is, the reflux ratio in Reference 8 is an optimal value mathematically obtained so as to maximize the evaluation function, and the reflux ratio in the first embodiment holds the instantaneous minimum theoretical step number _SM in a predetermined pattern. It was asked to do so. As can be seen from the relationship between the reflux ratio and the distillation time shown in FIG. 2, the rate of change (gradient) of the reflux ratio with respect to the change of the distillation time in the case of this example (solid line) is greater than that in the case of Reference 8 (dashed line). ) And stable operation can be obtained.

The optimum distillation time T in the batch packed distillation method of the first embodiment is 8.60 Hr, which is very close to the optimum distillation time: 8.52 Hr represented by Tinτ0 in Reference 8. . Here, τ0 is a time value (unit: H) obtained by dividing the charged amount of the undiluted distillation solution into the distillation still by the rising steam flow rate of the steam rising in the batch packed distillation column.
r), and the optimum distillation time T is a time value (unit: Hr) defined as T = total steam amount / rising steam flow rate. The ascending steam flow rate is the flow rate (unit: mol / Hr) of steam supplied from the evaporator to the batch packed distillation column per unit time, and the total steam amount is the total evaporation amount from the start of distillation to the end point of distillation excluding the operation before and after the distillation. (Unit: mol). The required amount of steam expressed as a ratio between the total amount of steam and the charged amount is a dimensionless value equal to the ratio of the optimum distillation time T to τ0 (T / τ0). Tinτ0 (= T / τ) which is the ratio of the optimal distillation time T to τ0 in Cases 1 to 23 of Table 1 in Reference 8.
In the case of 0), almost the same value is obtained. FIG. 3 shows the optimum distillation time obtained in Embodiment 1 and the reference 8 for Cases 1 to 24 shown in Tables 1 and 2 under the same separation conditions.
And the optimum distillation time (value obtained by dividing the actually consumed optimum time by τ0). In the following description, the optimum distillation time is used as including any meaning of the optimum time actually consumed as needed or the ratio of the actually consumed optimum time to τ0 (optimum batch time). I have. As described above, the optimal distillation time of Reference 8 and the instantaneous minimum theoretical number of steps S _M obtained by performing many complicated trial calculations by making use of esoteric mathematics using cost data.
The minimum theoretical number of steps S optimum distillation time of the present embodiment to be easily determined by distinct reflux policy of performing batch packed distillation made to match the _m and it is seen that shows a very good match. In the present embodiment, after performing the total reflux operation of the distillation stock solution and maintaining the batch packed distillation column 12 in a steady state, the batch packed distillation apparatus 10 in the batch packed distillation apparatus 10 is based on the change pattern of the reflux ratio determined as described above. By controlling the reflux ratio, the instantaneous minimum theoretical step number S representing the magnitude of the separation performance between the light key component and the heavy key component
The _M, are to perform the distillation to match the minimum theoretical number of steps S _m of a predetermined recovery rate is obtained.

[0043]

EXAMPLES Examples 1 to 5 which are more specific will be described below. (Example 1) In Example 1, the reflux ratio in each distillation stage was determined by applying the sequential calculation method. Here, 100 kmol of a 50% mixed solution of transdecalin (trans Decalin) of a light key component and cis decalin (cis decalin) of a heavy key component, which are in an isomer relationship, is placed in a batch packed distillation column having 50 theoretical plates N. A case in which transdecalin having an average distilling composition of 99.5% was recovered at a recovery rate of 90% will be described. Here, operating pressures 1.
33 × 10 ⁴ Pa (100 torr), rising steam flow rate 5
0 kmol / Hr, specific volatility α = 1.273,
Appropriate change patterns of the reflux ratio corresponding to these conditions were obtained by applying a sequential calculation method. Charged composition xF = 0.
5. Average distillate composition xDav = 0.995, recovery η1 =
From 0.90, η2 = η1 × (xF / (1-xF)) ×
((1-xDav) / xDav ) = a 0.0045, minimum theoretical number of steps S _m = ln (ln (1-0.9
0) / ln (1-0.0045)) / ln1.273 =
25.83, Still pot composition at end of distillation xE = (1−η1) ×
xF / (1−η1 × xF / xD) = 0.0913, the charged composition xF = 0.5 and the target attained composition xE = 0.
The area between 0913 and 913 was divided into 10 in consideration of the complexity of the calculation procedure. The number of divisions can be appropriately set to an appropriate value according to the required degree of calculation accuracy and calculation speed. Reflux in each distillation stage divided into a predetermined number of divisions, here 10 in consideration of the required calculation accuracy, using the McCabe-Seal sequential calculation method so that the minimum theoretical step number S _m is 25.83. The ratio and the instantaneous distillate composition were determined. Based on this value, numerical integration of each section was performed, and the distillation rate, required steam amount, and distillation time were obtained. The instantaneous minimum theoretical step number S _M (= ln ((xD
/ XB) / ((1-xD) / (1-xB))) / ln
The value of alpha) engineered to match the minimum theoretical number of steps S _m. Table 4 shows the results. The final required steam volume was 6.69 as shown in Table 4.

[0044]

[Table 4]

FIG. 4 is a graph showing the relationship between the distillation time and the reflux ratio obtained as described above, and FIG. 5 is a graph showing the relationship between the distillation time and the instantaneous distillate composition xD and the instantaneous residue composition xB. is there. As shown in FIG. 4, the reflux ratio increases as the distillation time elapses. It can be seen that the reflux ratio was about 8 at the beginning of distillation, but increased to about 20 to 40 after 10 to 13 hours at the end of distillation. On the other hand, as shown in FIG. 5, during this distillation period, the instantaneous distillate composition xD slightly decreases in the range of 1 to 0.98, but the instant kettle residual composition xB was initially 0.5. It can be seen that the value of the sample greatly decreased to 0.1 or less after about 13 hours.

Example 2 In Example 2, an appropriate change in the reflux ratio was determined by applying the shortcut method to the data under the same separation conditions as in Example 1. The results are shown in Table 4. In the second embodiment, the required steam amount is 7.53, which is the same as in the first embodiment.
This is a value greater than 69. Table 5 shows the data obtained here (pot composition, reflux ratio, distillation rate, required steam amount, distillation time,
xD, S _M ). FIG. 6 is a graph showing the relationship between the distillation time and the reflux ratio, and FIG. 7 shows the relationship between the distillation time and the instantaneous distillate composition xD and the instant kettle residual composition xB, which were created based on the data in Table 5. Things. 6 and 7, the tendency of the reflux ratio to increase as the distillation time elapses and the tendency to decrease the instantaneous distillate composition xD and the instantaneous vessel residual composition xB with the elapse of the distillation time can be seen from FIGS. 6 and 7. Here, the final required steam amount was 7.53 as shown in Table 5.

[0047]

[Table 5]

(Example 3) FIG. 8 is a graph showing the relationship between the bottom composition xB and the reflux ratio R, and FIG. 9 is a graph showing the relationship between the distillation time and the reflux ratio. In the third embodiment, under the same separation conditions as in the first embodiment, the change pattern of the appropriate reflux ratio is set as shown by a dotted line in FIG. As shown in FIG. Table 6 shows these detailed data. That is, here, based on the change in the reflux ratio (appropriate reflux ratio) obtained in the first embodiment, a piecewise operation in which the constant reflux ratio operation is stepwise changed within the range of the appropriate reflux ratio or more. Constant flux policy (Piecewise Constant)
(Reflux Policy). By changing the reflux ratio stepwise within a range that is equal to or more than the appropriate reflux ratio indicated by the dotted line in FIG. 8, the reflux ratio can be easily operated. FIG. 9 shows the data corresponding to FIG. 8 in the relationship between the distillation time and the reflux ratio.
The reflux ratio was changed stepwise from the start of distillation,
After 4 hours, the reflux ratio is set to about 40. The final required steam amount in Example 3 was 7.1.
5, which was not much different from 6.69 in Example 1.

[0049]

[Table 6]

Example 4 In Example 4, the composition of the distillation stock solution contained a third low boiling component in addition to a light key component (first low boiling component) and a heavy key component (second low boiling component). This is an example in which a change pattern of the reflux ratio is calculated by a shortcut method in the case of a component system. Here, the conditions in an ideal multi-component system with no waste liquid are set by using the concept of the optimal design and the optimal operation method that minimizes the production cost of batch-packing distillation under predetermined constraints. FIG.
FIG. 2 is a flow chart showing a batch filling distillation process. Here, as shown in the flow chart of FIG. 10, a distillation operation was performed in which the distillation stock solution was separated into a first fraction and a second fraction and taken out in two stages. This will be described below with reference to FIG. The charged molar compositions of the light key component a, the heavy key component b, and the third component c were Xa = 0.45, Xb = 0.35, X
When c = 0.20, each specific volatility is αac = 2.0, αbc =
The calculation was performed by setting 1.4 and αca = 1.0. The specifications of the purity of the products a to c corresponding to the components ac to be batch-distilled are 0.9 or more for the product a having a selling price of 2.5 値 / kmol and the selling price of 4.5 ＄ / kmol. Is 0.85 or more for the product b, and 0.95 or more for the product c whose selling price is 6.5 $ / kmol. Further, the rising steam flow rate in the distillation is 10 kmol / Hr, and the energy cost is 1
{/ Hr, raw material cost is zero, waste liquid cost is -0.1}
/ Hr was set for each condition.

By applying the shortcut method based on these data and calculating the recovery of the light key component a in the first fraction as η1 = 0.924 and the recovery in the heavy key component b as η2 = 0.1247, The minimum number of theoretical steps for minimizing the objective function for evaluating economic conditions is S _m = 8.3. Further, the recovery rates of the second fraction were η2 = 0.972 and η3 = 0.0878, respectively.
Then, the minimum theoretical step number is S _m = 10.87. Therefore, it is possible to maintain more way the minimum theoretical number of steps S _m moments at each distillation time by changing the reflux ratio as a target value of the minimum theoretical number of steps S _M obtained.

The value of the objective function φ for evaluating the above economic conditions can be calculated according to the description in Reference 2. For example, when the objective function φ is calculated with reference to the values and the like in the flowchart of FIG. 10, φ = 0.461 (distillation rate of the first fraction) ×
2.5 (sales price of product a) + 0.3494 (distillation rate of second fraction) x 4.5 (sale price of product b) + 0.1896 (remaining pot) x 6.5 (sale price of product c) −0.39 (energy cost of the first fraction) −0.33 (energy cost of the second fraction), and φ is 3.237 ° / kmol.
On the other hand, in the calculation example in Literature 2, the value of the objective function φ is φ = 0.7491４９ / k with the number N of theoretical stages being eight.
mol. From the above, it can be seen that the value of the objective function φ in the fourth embodiment is higher than that of the reference 2 and the economy is excellent.

The theoretical number of steps S of the batch packed distillation column used for the separation is set at about S / S _m = 2 and S = 22.
And The relationship between the reflux ratio and the distillation rate at this time is shown in FIG.
FIG. 12 shows the relationship between the instantaneous distillation composition xD and the distillation rate. As is clear from FIGS. 11 and 12, the reflux ratio and the instantaneous composition xD fluctuate greatly when the distilling rate is in the range of 0.4 to 0.5, and near the distillation end point of the first fraction xD (1). It can be seen that the change and the change near the start of distillation of the second fraction xD (2) can be explained.

Example 5 As Example 5, a search was made for the conditions for setting the number N of theoretical plates of a batch packed distillation column necessary for performing a more economical separation operation. In order to select a batch packed distillation column having the optimum number N of theoretical plates, the number N of theoretical plates was changed with respect to the separation conditions of Example 1 to obtain the number S of theoretical steps.
And the obtained relation minimum theoretical ratio S / S _m and Shoyo vapor of step number S _m. FIG. 13 shows the result. In general, as the number N of theoretical stages of the batch packed distillation column increases, the equipment cost increases, and as the number decreases, the variable cost increases. Using these relationships,
Economic data on distillation conditions (equipment costs, labor costs, utility costs, product costs, raw material costs, etc.)
Based on this, it is possible to appropriately design the distillation column in consideration of economic efficiency. As a result of various studies based on the data in FIG. 13 and the like, the appropriate value range of S / S _m is 1.3 centered on 2.0.
Could be considered to be in the ~ 2.7 range. On the other hand, in case 24 of Table 1, the minimum theoretical step number S _m =
17.01, the theoretical step number S = 21, and the S / S _m was 1.23. This value was within the appropriate range (1.3
~ 2.7), it is considered that an economically appropriate number of theoretical plates has not been selected.

(Comparative Example) As a comparative example, the operation was carried out at a constant reflux ratio during batch packed distillation. Here, 100 kmol of a 50% mixed solution of transdecalin and cisdecalin
Was charged into an evaporator of a batch packed distillation column having 50 theoretical plates, and 9 parts of transdecalin having an average distillate composition of 99.5% was added.
A distillation operation was performed to recover 0%. In this batch packed distillation, when a reflux ratio required for separation under operating conditions under which the reflux ratio was constant was determined, the reflux ratio was 31.0 as shown below. However, operating pressure 1.33x
10 ⁴ Pa, rising steam amount 50 kmol / hr, specific volatility of light key component to heavy key component is α = 1.2
73. Charge composition xF = 0.5, average distillate composition x
From Dav = 0.995 and the recovery η1 = 0.90, the composition xE in the bottom of the distillation at the end point of distillation is xE = (1-η1) x xF /
(1−η1 × xF / xD) = 0.0913. Next, the range of xF = 0.5 and xE = 0.0913 was divided into 10 as shown in Table 7.

[0056]

[Table 7]

Thus, the distillation rate, distillation time, instantaneous distillate composition xD, average distillate composition xDav, instantaneous minimum theoretical step number S _M (= ln ((xD / xB) /
Using the data of ((1-xD) / (1-xB))) / lnα), the reflux ratio R was determined as shown in Table 7. As can be seen from Table 7, the instantaneous minimum theoretical step number S _M is a large value at first, but sharply drops near the distillation end point. FIG. 14 shows the relationship between the distillation time and xD and xB obtained based on the data in Table 6. As shown in FIG. 14, while xB gradually decreases with the elapse of the distillation time, xB
It can be seen that D remains almost constant until about 25 hours later and sharply decreases after 25 hours. The required steam amount was calculated from the value of the distillation ratio and the reflux ratio using the relationship of required steam amount = distillation ratio × (reflux ratio + 1), and the calculated value was 14.48. As described above, the required steam amount (14.48) in the constant reflux ratio operation of the comparative example was the same as in Example 1.
14.48 / compared to the required steam volume (6.69) in the case of
6.69 = 2.16 times the amount is required. In comparison, the distillation time was 13.39 hours in the case of Example 1, whereas the comparative example was 29.23, which was nearly twice as large as that of Example 1.
It takes time.

The batch-packing distillation method applied to the batch-packing distillation apparatus 10 of the first embodiment has the following operation since it is configured as described above. (1) Since the instantaneous minimum theoretical step number S _M during batch-packing distillation is kept constant, it is easy to obtain almost the same result as the method using the optimum value that optimizes the evaluation function using Pontryagin's maximum principle. Can be. (2) As described in the shortcut method of the fourth embodiment,
If the light key component is to be separated as the main fraction,
This method can be applied to the case where the charged composition is multi-component. (3) Since distillation is performed by matching the instantaneous minimum theoretical step number S _M representing the separation performance during distillation with the minimum theoretical step number S _m at which a predetermined recovery rate can be obtained, a high recovery rate and efficient batch filling. Distillation separation becomes possible. (4) There is no occurrence of a pinch point at which the reflux ratio becomes lower than the minimum reflux ratio, so that the recovery rate per batch can be increased, and the required steam amount increases and the production rate increases rapidly. Is not reduced. (5) Energy loss can be suppressed, and personnel and equipment costs can be reduced. (6) In the case of fine chemicals for distilling expensive raw materials, it is required to obtain a large recovery rate. Therefore, the batch filling distillation method of the present embodiment is more effective. (7) By adopting the batch packed distillation method in which the instantaneous minimum theoretical step number S _M is kept constant, the reflux ratio is appropriately changed so as not to generate a pinch point, and the capacity of a high number of batch packed distillation columns is maximized. By drawing to the limit, a more efficient distillation operation becomes possible. (8) It is possible to appropriately cope with the separation of isomers or the like which have a small specific volatility and require a high number of theoretical plates and are difficult to separate. (9) It is possible to design a batch packed distillation column that satisfies the optimum conditions by using the relationship between the required steam amount and S / S _m . (10) Considering that the batch filling distillation method according to the present embodiment is an optimum reflux operation method and considering that this reflux ratio operation is performed, as shown in FIG. 13, the relationship between the required steam amount and the S / S _m as shown in FIG. Can be calculated. Thus, the theoretical plate number N corresponding to the optimum condition can be obtained based on the economic data.

[0059]

According to the batch filling distillation method of the present invention, the following effects can be obtained. (A) From a distillation stock solution having a small specific volatility and difficult to separate,
Using a batch packed distillation column with a high number of theoretical plates, making effective use of the separation performance of the distillation column, efficiently recovering high-purity products in high yields and obtaining products at low cost Can be. (B) The mechanism of the operation is clear, and the composition change during the distillation can be sequentially grasped by calculation. Therefore, it is possible to appropriately cope with the fluctuation during the operation only by adjusting the reflux ratio. (C) by adjusting the reflux ratio (Equation 2) is the instantaneous constantly minimum theoretical number of steps S _M as defined in (Equation 1)
In to match the minimum theoretical number of steps S _m which is defined, i.e., since in order to maintain the state of the batch packed distillation corresponding to the number of theoretical plates constant total reflux distillation, the equilibrium relationship between the components in each theoretical plate Is properly maintained, and the batch filling distillation of the distillation stock solution can be efficiently performed. (D) The operation pattern of the reflux ratio from the start to the end of batch-packing distillation is defined as the instantaneous minimum theoretical step number S during this period.
_Batch filling distillation operation can be performed according to this pattern in advance so that _M becomes a predetermined value, so that batch filling distillation operation can be performed appropriately and reliably without directly measuring the temperature, pressure, etc. of the distillation stock solution. To obtain a distillate having a predetermined recovery rate and a predetermined purity or a bottom liquid. (E) The reflux ratio can be set corresponding to the instantaneous minimum theoretical step number S _M simply by determining the minimum theoretical step number S _m that is the target value. , And batch batch distillation of the distillation stock solution can be performed efficiently and economically under conditions where the separation conditions are optimized. (F) the minimum theoretical number of steps S _m is, .eta.1, .eta.2, because it is set only 3 variables alpha, the set easily target value without requiring complicated iterative calculations, adjusted reflux ratio accordingly It can be done efficiently. (G) The batch packed distillation column is increased from the minimum theoretical step number _Sm to 1
Has a greater number of theoretical stages N than the value obtained by subtracting
In addition, it can be performed reliably, and the productivity of batch packed distillation can be increased. (H) Since a batch packed distillation column having a theoretical plate number N larger than the minimum theoretical step number S _m -1 is used, stable operating conditions can be easily ensured, and the operation can be performed under a condition having a sufficient space. Can be efficiently separated. (I) Number of theoretical plates N = 50, charge composition xF = 0.5, specific volatility α = 1.273, average distillate composition xDav = 0.99
5. When the recovery η = 0.90, the newly developed batch distillation method is about 1 /
A distillation time of 2 is sufficient, and productivity can be significantly increased.

According to the batch filling distillation method of the second aspect, the following effects are obtained. (A) The instantaneous minimum theoretical step number S _M is defined by (Equation 2), and the minimum theoretical step number S _m to be the target value is determined at the end point of the batch filling distillation by using the distillation stock solution having a predetermined component composition. Since the distillate having a predetermined recovery rate and purity and the bottom liquid can be separated most efficiently (formula 1), the reflux ratio is adjusted to a predetermined range using this. As a result, the batch-packing distillation operation can be appropriately and efficiently performed under conditions that can optimize the separation performance. (B) Since the actual reflux ratio is set within a range not less than the reflux ratio required to maintain the instantaneous minimum theoretical step number S _M at the minimum theoretical step number S _m , the reflux ratio is controlled with a sufficient margin. can do. (C) Since a necessary change pattern of the appropriate reflux ratio can be determined in advance and the reflux ratio can be changed stepwise within a range not less than the appropriate reflux ratio, the occurrence of a pinch point can be avoided and the reflux ratio can be reduced. The operation can be easily performed. (D) By incorporating the constant reflux ratio operation, the distillation time is slightly longer than in the case where the reflux ratio is continuously changed, but the operation is easy and stable operation is possible.

According to the batch filling distillation method of the third aspect, the following effects can be obtained by this configuration in addition to the effects obtained by the first or second aspect. (A) Since the number of theoretical steps S of the batch packed distillation column is limited to a specific range larger than the minimum number of theoretical steps S _m −1,
Furthermore, the batch filling distillation operation can be performed more efficiently, and the recovery rate can be improved. (B) Since S / _Sm is selected in an appropriate range, an economical batch-packing distillation operation with good recovery can be performed. (C) Since S / S _m is selected in an appropriate range, an economically appropriate batch packed distillation column can be designed.

According to the batch filling distillation apparatus of the fourth aspect, the following effects can be obtained. (A) Using a batch packed distillation column with a high number of theoretical plates from a distillation stock solution having a small specific volatility and difficult to separate, effectively utilizing the separation performance of the distillation column to efficiently produce high-purity products. It can be recovered in a yield, and is excellent in energy saving and productivity. (B) Since there is provided a control unit for adjusting the reflux ratio during batch packed distillation so that the instantaneous minimum theoretical step number becomes a predetermined target value, the state of batch packed distillation corresponding to total reflux distillation with a fixed number of theoretical stages , And the batch filling distillation of the distillation stock solution can be efficiently performed. (C) Since the control unit for monitoring the batch filling distillation operation by comparing the data acquired by the liquid level meter or the weighing scale with the preset target data is provided, the temperature and pressure of the undistilled solution are directly measured. It is possible to monitor the operation of batch-packing distillation appropriately and reliably without obtaining a distillate or a bottom residue having a predetermined recovery rate and a predetermined purity. (D) The reflux ratio can be set corresponding to the target value (minimum theoretical step number S _m ) of the instantaneous minimum theoretical step number S _M by simply determining the target value. It is possible to efficiently and economically perform batch-packed distillation of the distillation stock under the appropriate conditions under which the number of theoretical plates is constant. (E) In the case where the batch packing distillation column is filled with the regular packing, each of the voids formed by the regular packings is stably and uniformly secured as a flow path for the vapor and the reflux liquid by each of them. The amount of liquid (hold-up) staying in the stage can be reduced to maintain the gas-liquid equilibrium relationship properly, and the result can be applied assuming that there is no hold-up, and the calculation can be simplified. .

According to the batch packed distillation apparatus of the fifth aspect, the following effect is obtained in addition to the effect of the fourth aspect. Since the theoretical number of steps S of (a) batch packed distillation column is limited to a specific range for the minimum theoretical step number S _m, the further it is possible to efficiently perform batch packed distillation operations, enhance the recovery rate Can be. (B) Since S / _Sm is selected in an appropriate range, an economical batch-packing distillation operation with good recovery can be performed. (C) Since S / S _m is selected in an appropriate range, an economically appropriate batch packed distillation column can be designed.

According to the batch filling distillation apparatus of the sixth aspect, the following effect is obtained in addition to the effect of the sixth aspect. (A) Since the batch packing distillation column is filled with the structured packing, a flow path for vapor or reflux liquid is formed between the structured packings or in pores or depressions formed in the structured packing, Stable and uniform mass transfer can be ensured in the batch packed distillation column. (B) The amount of liquid accumulated and retained in each stage of the batch packed distillation column (hold-up) can be reduced, and the gas-liquid equilibrium relationship can be effectively maintained. (C) The result assuming that there is no hold-up can be applied, and the calculation can be performed easily. (D) Since the gas-liquid contacting efficiency is better than the case where the random packing is used, the effective height of the batch packed distillation column can be reduced, and a batch packed distillation column with high efficiency and low cost can be designed. (E) Since the reflux liquid is less likely to accumulate between the structured packing and the structured packing, the residence time of the reflux liquid in the column can be shortened.

According to the batch filling distillation apparatus of the seventh aspect, the following effect is obtained in addition to the effect of any one of the fourth to sixth aspects. (A) Since a low-temperature condensate is directly heat-exchanged with inlet steam because of having a knock-back type condenser, heat transfer efficiency is good and a reflux temperature close to the boiling point can be secured. (B) Since the knockback type condenser is installed at the top of the distillation column, the reflux operation can be performed by using gravity without using a reflux pump.

According to the batch filling distillation apparatus of the eighth aspect, the following effect is obtained in addition to the effect of any one of the fourth to seventh aspects. (A) It is most suitable for distillation in which the operation is performed while keeping the vapor amount constant, and is particularly suitable for batch packed distillation in which vacuum distillation is often required.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a batch packed distillation apparatus to which a batch packed distillation method according to a first embodiment is applied.

FIG. 2 is a graph showing the correlation between the optimum distillation time and the optimum distillation time in Reference 8.

FIG. 3 is a graph showing the correlation between the optimal distillation time in Embodiment 1 and the literature.

FIG. 4 is a graph showing the relationship between distillation time and reflux ratio.

FIG. 5: Distillation time, instantaneous distillate composition xD, instantaneous pot remaining composition x
Graph showing the relationship with B

FIG. 6 is a graph showing the relationship between distillation time and reflux ratio.

FIG. 7: Distillation time, instantaneous distillate composition xD, instantaneous pot remaining composition x
Graph showing the relationship with B

FIG. 8 is a graph showing the relationship between the bottom composition and the reflux ratio.

FIG. 9 is a graph showing the relationship between distillation time and reflux ratio.

FIG. 10 is a flow diagram illustrating the process of batch packed distillation in a multi-component system.

FIG. 11 is a graph showing a relationship between a reflux ratio and a distillation rate.

FIG. 12 is a graph showing the relationship between the instantaneous distillation composition xD and the distillation rate.

FIG. 13 is a graph showing a relationship between S / S _m and a required steam amount.

FIG. 14 is a graph showing the relationship between distillation time and xD and xB.

[Explanation of symbols]

 10 Batch filling distillation apparatus 11 Distillation tank 12 Batch filling distillation column 13 Knockback type condenser 14 Reflux control valve 15 Distillate control valve 16 Distillate receiver 17 Liquid film falling reboiler 18 Circulation pump 19 Vent condenser 20 Level gauge 21 Weight scale 22 Packed bed

[Procedure amendment]

[Submission date] March 29, 2001 (2001.3.2)
9)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Fig. 1

[Correction method] Change

[Correction contents]

FIG.

Claims (8)

[Claims] 1. A distillation stock solution containing a low-boiling light key component and a high-boiling heavy key component is subjected to a reflux operation using a batch packed distillation column to form a distillate and a bottom residue at a predetermined recovery rate, respectively. A batch packed distillation method for separating, comprising using a batch packed distillation column having a theoretical plate number N larger than the minimum theoretical step number S _m -1 defined by (Equation 1), and adjusting a reflux ratio in the reflux operation. Wherein the instantaneous minimum theoretical step number S _M defined by (Equation 2) is matched with the minimum theoretical step number S _m for distillation. _{S m = ln (ln (1} -η1) / ln (1-η2)) / lnα ---- ( Equation 1) (wherein, .eta.1 the recovery of the distillate right key components, .eta.2
Represents the recovery rate of the heavy key component in the distillate, and α represents the relative volatility of the light key component to the heavy key component. ) S _M = ln ((xD1 / xD2) / (xB1 / xB2)) / lnα (2) where xD1 is the instantaneous distilling composition of the light key component, xD2
Represents the instantaneous distillation composition of the heavy key component, xB1 represents the instantaneous residue composition of the light key component, and xB2 represents the instantaneous residue composition of the heavy key component. ) 2. A distillation stock solution containing a low-boiling light key component and a high-boiling heavy key component is subjected to a reflux operation using a batch packed distillation column to form a distillate and a bottom residue at a predetermined recovery rate, respectively. A batch packed distillation method for separating, comprising using a batch packed distillation column having a theoretical plate number N larger than the minimum theoretical step number S _m -1 in the batch packed distillation method according to claim 1, and refluxing in the reflux operation. Distilling by setting the ratio in a range of a reflux ratio or more necessary to maintain the instantaneous minimum theoretical step number S _M in the batch packed distillation method according to claim 1 at the minimum theoretical step number S _m. A batch filling distillation method, characterized in that: 3. The theoretical number of steps S of said batch packed distillation column
But, 1.3S _m ≦ S ≦ 2.7S _m batch packed distillation method according to claim 1 or 2, characterized in that it is controlled so as to satisfy the conditions. 4. A distillation pot in which a stock solution containing a low-boiling light key component and a high-boiling heavy key component is charged; (b) a reboiler for circulating and heating the distillation stock solution in the distillation pot; A) a batch packed distillation column having a theoretical plate number N in which the steam generated by heating in the reboiler is passed and the packing is arranged; and (d) a condenser for condensing the fraction distilled from the top of the batch packed distillation column. (E) a reflux mechanism having a control valve for distributing the distillate condensed in the condenser and taken out to the distillate receiver and the reflux liquid returned to the batch packed distillation column at a predetermined reflux ratio; A) a level gauge for detecting a liquid level and / or a weight scale for detecting the weight of the liquid level provided in the distillation still and the distillate receiver; and (g) operating the reflux mechanism. In the batch filling distillation method described Between minimum theoretical number of steps S _M with adjusting the reflux ratio to match the minimum theoretical number of steps S _m, as compared with the target data set with the data acquired in advance by the liquid level meter or the weighing scale A batch packed distillation apparatus, comprising: a control unit that monitors batch packed distillation and controls the reflux mechanism. 5. The theoretical number of steps S plus the number of stages 1 theoretical plates N in the distillation still of the batch packed distillation column, a minimum theoretical number steps in has been batch packed distillation method according to claim 1 and a S _m In this case, the number of steps S is 1.3S _m ≦ S ≦
Batch packed distillation apparatus according to claim 4, characterized in that it comprises a control unit for controlling so as to satisfy the condition of 2.7 s _m. 6. The batch according to claim 4, wherein the batch packed distillation column is provided with an ordered packing composed of at least one of a metal plate, a wire mesh type and a grid type in the column. Packing distillation equipment. 7. The capacitor according to claim 4, wherein said capacitor is a knock-back type capacitor.
Batch distillation apparatus according to Item. 8. The batch packed distillation apparatus according to claim 4, wherein the reboiler is formed by a liquid film falling type of an external circulation.