JPH11314010A - Method and apparatus for liquid-liquid separation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automate separation of a mixed solution of various non-phase soluble liquids by a method wherein the mixed solution capable of being separated into at least two layers is separated by standing still, and a branch passage is changed by variation of a mass flow rate by making the solution flow out successively from a lower layer side solution. SOLUTION: In the case where, for example, two liquids are separated, a container 11 containing a mixed solution of two liquids as an object to be separated is allowed to stand still after stirring to be separated into two liquids, and a controller 4 keeps a specific pressure in the container 11 during separation treatment by a pressure regulator 3 to keep a primary side pressure of a mass flowmeter 12 also at the same pressure. The controller 4 opens automatic valves 15, 17 at a bottom of the container, closes an automatic valve 18, and allows a liquid on a lower layer side in the container 11 to flow to a storing container 13. When the lower layer side liquid in the container 11 is gone, the upper side liquid starts to flow out, the controller 4 judges passage through the flowmeter 12 on a liquid border between an lower layer side and an upper layer side by a variation of a signal based on the mass flow rate of the liquid of the mass flowmeter 12, closes the automatic valve 17, opens the automatic valve 18, and allows the upper layer side liquid to flow to the storing container 14. Thereby, even liquids having near densities can be automated to be separated from each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid-liquid separation method and a liquid-liquid separation apparatus for separating at least two incompatible liquids and separately recovering the separated liquids.

[0002]

2. Description of the Related Art In an organic synthesis plant of a drug substance factory or a chemical factory, a liquid-liquid separation operation is performed to separate a by-product generated by an organic chemical reaction from a main product. In this liquid-liquid separation operation, first, a solvent that does not dissolve in each other is stirred and mixed in a container, and then the mixture is allowed to stand to be separated into two layers of liquid. At this time, the main product and the by-product exist in different layers of the separated liquid layer. The liquid in the lower layer and the liquid in the upper layer are allowed to flow out of the container in this order, and the liquid in the lower layer and the liquid in the upper layer are flown into separate flow paths by switching a valve provided in the flow path to be separated. . that time,
Conventionally, an operator looks into a monitoring window provided in the middle of the flow path,
The color tone of the liquid passing through the monitoring window is visually observed to determine the interface between the upper and lower liquids, and the manual valve is switched.

However, the colors of the separated liquids are often not distinctly different, and the colors of the respective liquids are very slightly different. Therefore, skill is required to determine the interface, and the reproducibility is reliable. It is difficult to perform liquid separation, that is, switch valves. Furthermore, during the operation of liquid-liquid separation, the operator has to wait for a long time near the monitoring window only to monitor the monitoring window and switch the valve, resulting in an increase in labor costs.

[0004] Then, by automatically detecting the interface of the separated liquid by a sensor and controlling the valve for switching the flow path automatically, the liquid-liquid separation operation is automated, and the switching error of the valve is prevented. This makes it possible to reliably perform liquid separation with good reproducibility, and to reduce costs by reducing labor.

[0005] In order to achieve such an object, it has been proposed to perform liquid-liquid separation using, for example, a density detector as a sensor for detecting an interface (Japanese Patent Publication No. Hei 7-14441).
issue). In this proposal, a liquid separated into two or more layers is passed through a density detector, and based on a change in the density of the liquid when passing through it, an interface between different liquids is recognized by an arithmetic mechanism,
The valve for switching the flow path is automatically switched.

There have also been proposals for liquid-liquid separation using a moisture meter based on microwaves as a sensor for detecting an interface, and for liquid-liquid separation using an ultrasonic sensor.

[0007]

However, in the proposal using a density detector, the interface between different types of liquids is recognized based on the density difference of the liquids passing through the density detector. However, it is very difficult to recognize the interface between liquids having similar densities.

In the proposal using a moisture meter based on microwaves, the interface between different types of liquids is recognized based on the difference in the absorptivity of microwaves absorbed by moisture in the liquid. It is not possible to recognize the interface between liquids that do not contain moisture, ie, do not absorb microwaves, like liquids. Therefore, liquids containing no water cannot be separated.

Further, in the proposal using an ultrasonic sensor, the interface between liquids of different types is recognized based on the difference in characteristics with respect to ultrasonic waves, and therefore the interface between liquids with similar characteristics to ultrasonic waves cannot be recognized. . That is, it is not possible to separate such combinations of liquids.

The present invention has been made under such circumstances, and an object of the present invention is to provide a liquid / liquid mixture capable of reliably and automatically performing separation of a mixture of various incompatible liquids with good reproducibility. An object of the present invention is to provide a separation method and a liquid-liquid separation device for performing the method.

[0011]

In order to achieve the above object, the present invention comprises a step of allowing a mixed solution containing at least two kinds of liquids to be separated into at least two layers by allowing the mixture to stand, Measuring the mass flow rate of the two liquids while sequentially flowing them out of the lower liquid; and providing at least two flow paths for the liquids based on a change in the measured mass flow rates.
Switching to one of the two branched paths.

Further, in order to carry out the above method, the present invention provides:
A container that contains a liquid mixture containing at least two liquids and that can be separated into at least two layers, and a container that separates the liquid mixture by allowing the liquid mixture to stand still; A flow path for flowing out of the liquid, a mass flow meter provided in the middle of the flow path, for measuring a mass flow rate of the liquid flowing through the flow path, and a flow path provided in the middle of the flow path to adjust the opening degree of the flow path Adjusting means, a branch path branched into at least two flow paths downstream of the adjusting means and the mass flow meter,
Switching means for switching a liquid flow path to one of the branch paths, wherein the switching means is controlled to switch based on a change in the mass flow rate of the liquid measured by the mass flow meter. A liquid separation device is provided.

[0013]

FIG. 1 is a schematic diagram showing an example of a liquid-liquid separation device used for carrying out a liquid-liquid separation method according to the present invention. Although not particularly limited, in this example, a case where two types of liquids are separated will be described to simplify the description.

This separation device separates the liquid into two layers in a container 11 and sequentially passes each liquid flowing out of the container 11 through a mass flow meter 12, based on a difference in the mass flow rate of the liquid when passing therethrough. Are separately flowed into two storage containers 13 and 14 provided on the downstream side. That is, different types of liquids are separated and stored in the storage containers 13 and 14.

The lower end of the container 11 is connected to a flow path 21 for allowing the liquid in the container 11 to flow out. The flow path 21 is connected to the primary side of the automatic valve 15, and the secondary side of the automatic valve 15 is connected to the inlet side of the mass flow meter 12 via the flow path 22.

The outlet side of the mass flow meter 12 is connected through a flow path 23 to the primary side of the control valve 16. Control valve 1
6 is connected to the two branches 2
5 and 26, and are connected to the primary sides of the automatic valves 17 and 18, respectively. The secondary sides of the automatic valves 17 and 18 are connected to the storage containers 13 and 1 via flow paths 27 and 28, respectively.
4 is connected.

The container 11 is adjusted by the pressure regulator 3 so that the pressure in the container becomes constant during the separating operation.
The pressure regulator 3 is driven and controlled by a control device 4 such as a computer. Further, a stirring device including a rotating stirring blade (not shown) is provided in the container 11 so that the mixed liquid in the container 11 can be stirred. When the stirring blade is left standing still, the liquid in the container 11 separates into, for example, two layers.

The mass flow meter 12 includes, for example, two flow tubes, and when these flow tubes are vibrated, when the liquid flows through the flow tubes, the two flow tubes have opposite inlets and outlets. The flow tube vibrates with slight distortion due to the Coriolis force of
A phase difference of vibration appears at two points, an inlet and an outlet, and the fact that this phase difference is proportional to the mass flow rate is used, and the phase difference is detected. In the mass flowmeter having such a configuration, when the liquid is not flowing in the flow tube, the flow tube repeats symmetrical vibration, and therefore, there is no phase difference of the vibration between the inlet and the outlet. The mass flow meter 12 is not limited to the one that detects the phase difference of the vibration of the flow tube, and may have any configuration as long as the mass flow rate of the passing liquid can be continuously and automatically measured. .

The automatic valve 15 is controlled to be opened and closed by the control device 4 and controls the outflow and the stop of the liquid from the container 11.

The control valve 16 is controlled by the control device 4 to have a predetermined opening degree.
Adjust the flow rate of the liquid flowing through. Therefore, the control valve 16 has a function as a control means.

The control valve 16 is useful for detecting an interface between two liquids to be separated when there is a difference in viscosity between the two liquids even if there is not much difference in density between the two liquids. That is, in the case of liquid-liquid separation, it is necessary to flow the liquid so as not to disturb the interface, and the flow is laminar. In the laminar flow region, since the flow depends on the interaction between the pipe wall surface and the liquid, the volumetric flow rate V (the flow velocity of the liquid) greatly differs depending on the viscosity of the liquid. In this case, the relational expression between the volume flow rate V and the viscosity μ is expressed by the following equation (1).

V = Ns (Fs Cv) 3/2 (P2−P1) / μ (1) where Ns is a constant for correcting the unit in the equation. Fs is a flow constant in the case of a laminar flow, and is an amount that depends on the type of the control valve 16 and is a value around 1.0 (an amount that becomes constant once the control valve 16 is determined). Cv is a flow coefficient of the control valve 16, and is an amount that becomes constant if the pressure before and after the control valve 16 is determined. P1 and P2 are the pressures on the primary and secondary sides of the control valve 16, respectively. As can be seen from the equation (1), the volume flow rate V and the viscosity μ are inversely proportional. The volume flow rate V decreases as the viscosity μ increases, and the volume flow rate V increases as the viscosity μ decreases. Since the relationship between the mass flow rate M and the volumetric flow rate V is expressed by equation (2), the mass flow rate difference ΔM between the two liquids (the density and volumetric flow rates of one liquid are ρ1 and V1 and the other is ρ2 and V2) is (3) Therefore, even if there is not much difference between the densities ρ1 and ρ2, if there is a difference in the viscosity μ, there is a difference in the volume flow rates V1 and V2, and from the equation (3) a mass flow rate difference ΔM is generated. Become.

M = ρV (2) ΔM = (ρ2V2−ρ1V1) (3) Both the automatic valves 17 and 18 are controlled to open and close by the control device 4, and both of them are controlled. Close or open exclusively.
When one automatic valve 17 is opened and the other automatic valve 18 is closed, the liquid flowing out of the container 11 flows through a series of flow passages from the flow passage 21 to the branch passage 25, passes through the automatic valve 17 and passes through one storage container. It flows into 13. On the other hand, one automatic valve 17
Is closed and the other automatic valve 18 is opened, the liquid flowing through a series of flow paths from the container 11 to the branch passage 26 flows through the automatic valve 18 into the other storage container 14. Therefore, these automatic valves 17 and 18 have a function as switching means for switching the liquid flow path.

The control device 4 controls the opening and closing of the automatic valves 15, 17, 18 and the opening of the control valve 16. This control device 4
, A detection signal based on the mass flow rate of the liquid passing therethrough is input from the mass flow meter 12. The control device 4 determines a change state of the input signal and automatically generates a control signal for switching the opening and closing of the valve so that only one of the automatic valves 17 and 18 in front of the storage containers 13 and 14 is opened. Valve 1
7 and 18.

Next, a procedure for separating two liquids, for example, using the above-described liquid-liquid separation device will be described. First, after stirring the inside of the container 11 containing the mixed liquid of the two liquids to be separated, the liquid is allowed to stand and separated into two liquids. Then, the control device 4 outputs a control signal for adjusting the pressure in the container to the pressure regulator 3. Thereby, the pressure in the container 11 becomes a predetermined pressure, for example, 150 kPa.
-It is controlled to be kept at G. The pressure in the container is
It is controlled constant during the liquid separation process. That is, the mass flow meter 12
During the liquid separation process, the pressure on the primary side is always 150 kPa, for example.
・ It is kept at G.

The control device 4 outputs control signals for opening and closing to the automatic valve 15 at the bottom of the container and the automatic valves 17 and 18 of the branch passages 25 and 26 to open the automatic valves 15 and 17 respectively. Close 18. As a result, the liquid starts to flow out from the bottom of the container 11, and the lower liquid in the container 11 that flows first flows into the storage container 13 on the automatic valve 17 side and is stored.

The control device 4 also controls the automatic valves 15, 1
Along with controlling the opening and closing of the switches 7 and 18, a control signal for adjusting the opening is output to the control valve 16. Thereby, the opening degree of the control valve 16 is controlled so as to be always constant during the liquid separation process.

While the lower liquid in the container 11 flows out and passes through the mass flow meter 12, the mass flow meter 12 continuously outputs a signal based on the mass flow rate of the lower liquid to the controller 4. I do.

When the liquid on the lower layer side in the container 11 runs out,
The upper liquid starts to flow out. When the liquid on the upper layer side starts passing through the mass flow meter 12, the mass flow meter 12 continuously outputs a signal based on the mass flow rate of the liquid on the upper layer side to the control device 4.

The controller 4 detects a change in the signal sent from the mass flow meter 12 and determines that the interface between the lower liquid and the upper liquid has passed through the mass flow meter 12. Then, control signals for opening and closing are output to the automatic valves 17 and 18 of the branch passages 25 and 26, respectively, to close the automatic valve 17, and
The automatic valve 18 is opened. Thereby, the liquid on the upper layer side flows into the storage container 14 on the automatic valve 18 side and is stored.

In the case where the change in the mass flow rate when the liquid passing through the mass flow meter 12 changes from the lower layer liquid to the upper layer liquid is small and the control device 4 cannot detect the passage through the interface. As described above, when the liquid on the upper layer reaches the control valve 16, a change in the mass flow rate occurs due to the difference in viscosity between the liquid on the lower layer and the liquid on the upper layer. The control device 4 changes the signal based on this change to the automatic valves 17 and 18.
Is opened and closed, and the upper liquid is stored in the storage container 14.
Flow to

According to the above embodiment, the mass flow meter 12
To continuously measure the mass flow rate of the liquid passing therethrough, and automatically switch the flow paths of the storage containers 13 and 14 by the control device 4 based on the change in the mass flow rate.
The liquid on the upper layer side and the liquid on the lower layer side separated in 1 can be automatically and reliably reproducibly separated. Therefore, an operator for visually checking the interface between the liquid on the upper layer side and the liquid on the lower layer side and manually switching valves and the like is not required, thereby saving labor and reducing costs due to human rights costs. At the same time, it is possible to prevent artificial liquid-liquid separation errors.

Further, according to the above-described embodiment, the liquid in the upper layer and the liquid in the lower layer are separated based on the change in the mass flow rate. Even close liquids can be reliably and automatically separated with good reproducibility.

In the above, the present invention is not limited to the separation of two liquids, and may separate three or more liquids. In this case, a switching means is provided which branches the flow path 24 downstream of the control valve 16 into a number of flow paths corresponding to the type of liquid to be separated, and each branch path is opened and closed by the control device 4. What is necessary is just to connect and connect a storage container via an automatic valve.

[0035]

EXAMPLES Specific examples are shown below to further clarify the features of the present invention.

Example 1 Using the liquid-liquid separator shown in FIG. 1, water (density: 1000 kg / m 3, viscosity: 1.0 × 1)
0-3 Pa · s) and N-heptane (density: 680 kg / m)
3. Separation of the two liquids from a mixture of the two liquids having a viscosity of 0.41 × 10 −3 Pa · s). First, a mixed solution of water and N-heptane was put in the container 11, and left standing after stirring. The liquid in the container 11 was separated into two layers. The rate of change of the density between water and N-heptane was 32.0%.

Thereafter, the pressure in the container 11 is adjusted by the pressure regulator 3
To 150 kPa · G, and the pressure in the container was maintained during the liquid separation treatment. The pressure on the storage containers 13 and 14 side was normal pressure. The automatic valves 15 and 17 were opened, the automatic valve 18 was closed, and the control valve 16 was adjusted so that the opening was constant. The liquid (water) on the lower layer side becomes laminar flow and the automatic valve 15,
It flowed to the storage container 13 through the mass flow meter 12, the control valve 16 and the automatic valve 17. The mass flow rate at that time is 8.25 × 1
It was 0-2 kg / s.

When the water in the container 11 disappears, N-heptane starts flowing out, and when the interface passes through the mass flow meter 12, the mass flow rate changes to 5.61 × 10−2 kg / s, and the rate of change is changed. 32.0% (see FIG. 2). The controller 4 detected this change and opened the automatic valve 18 at the same time as closing the automatic valve 17, whereby the N-heptane could flow to the storage container 14 and be separated from the water. The Reynolds numbers of water and N-heptane were 2100 and 3 respectively.
490.

Example 2 Dichloroethane (density: 1280 kg / m 3, viscosity: 0.5 cP) and glycerin (density: 1260 kg /
Separation of the two liquids was performed from a mixture of the two liquids (m3, viscosity: about 300 cP). First, a mixed solution of dichloroethane and glycerin was put into the container 11, and the mixture was stirred and allowed to stand. The liquid in the container 11 was separated into two layers. The rate of change of the density between dichloroethane and glycerin was 1.56%.

Thereafter, the pressure in the container 11 is adjusted by the pressure regulator 3
To 150 kPa · G, and the pressure in the container was maintained during the liquid separation treatment. The pressure on the storage containers 13 and 14 side was normal pressure. The automatic valves 15 and 17 were opened, the automatic valve 18 was closed, and the control valve 16 was adjusted so that the opening was constant. The liquid (dichloroethane) on the lower layer side becomes turbulent and becomes an automatic valve 15, a mass flow meter 12, a control valve 16, and an automatic valve 1.
7 and flowed to the storage container 13. The mass flow rate at that time was 4.17 × 10 −3 kg / s.

Dichloroethane disappears in the container 11,
When glycerin began to flow out and its interface passed the mass flow meter 12, the controller 4 could not detect a change in mass flow. Then, when glycerin passed through the control valve 16, the mass flow rate was 1.67 × 10 −3 kg / s, and a change in the mass flow rate of 60% occurred (see FIG. 2). The controller 4 detected this change and opened the automatic valve 18 at the same time as closing the automatic valve 17, whereby the glycerin flowed to the storage container 14 and could be separated from dichloroethane.

The Reynolds number of dichloroethane is 5000
, Which is a value far exceeding the turbulence region. Thus, a change in viscosity does not affect the flow rate. However, the Reynolds number of glycerin is about 60, and the flow is laminar.
Therefore, the flow velocity has viscosity dependency, and the flow velocity is greatly reduced.

As can be seen from the above examples, according to the present invention, two liquids can be separated even if there is almost no difference in density.
It turns out that it is more effective than using a density detector.

[0044]

As described above, according to the present invention, even if a mixture of various incompatible liquids, particularly liquids having close densities, organic liquids, or liquids having similar characteristics to ultrasonic waves, The separation can be reliably automated with good reproducibility.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an example of a liquid-liquid separation device according to the present invention.

FIG. 2 is a table showing the results of Examples.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Container 12 Mass flow meter 13,14 Storage container 15 Automatic valve 16 Control valve (adjustment means) 17,18 Automatic valve (switching means) 21,22,23,24,27,28 Channel 25,26 Branch path 3 Pressure Regulator 4 Controller

Claims (2)

[Claims] 1. A step of allowing a mixture containing at least two kinds of liquids and being separable into at least two layers to stand still, and separating the at least two kinds of liquids sequentially from the lower liquid, Measuring the mass flow rate, and switching the liquid flow path to one of at least two branch paths based on a change in the measured mass flow rate. Liquid separation method. 2. A container for storing a liquid mixture containing at least two liquids and capable of being separated into at least two layers, and allowing the liquid mixture to stand and separate, and at least two liquids separated in the container. And a mass flow meter that is provided in the middle of the flow path and measures the mass flow rate of the liquid flowing through the flow path, and is provided in the middle of the flow path, Adjusting means for adjusting the opening degree; a branch path branched into at least two flow paths downstream of the adjusting means and the mass flow meter; and a liquid flow path is switched to one of the branch paths. A liquid-liquid separation device, comprising: switching means, wherein the switching means is controlled to be switched based on a change in the mass flow rate of the liquid measured by the mass flow meter.