JPH06148156A - Monitoring device - Google Patents

Abstract

PURPOSE:To detect a component extracted and separated in supercritical state by reducing the pressure of a supercritical fluid in which the component in a product is dissolved, and monitoring the fluid as a gas-liquid two phase fluid. CONSTITUTION:In a supercritical chromatograph, liquid carbon dioxide supplied from a bomb 57 is formed into a supercritical fluid by regulating its temperature and pressure by a tank body 52 in a thermostatic tank 51 and pressure regulating valves 84, 86, respectively. This supercritical fluid extracts and dissolves a component contained by a product from a vessel 59, and is then supplied to a separation column 54. In this case, to regularly monitor which component is dissolved in the supercritical fluid eluted from the output of the column 54, a pressure regulating valve 21 is provided. Thus, the supercritical fluid is reduced in pressure, and formed into a gas-fluid two phase fluid, which is then supplied to a monitor part 20. On the other hand, a three-way valve 83 is switched on the basis of the monitoring result in the monitor part 20, the gas-liquid two phase fluid is branched and recovered in recovering vessels 85, 87 through the pressure regulating valves 84, 86.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a monitoring device.

[0002]

2. Description of the Related Art Conventionally, a supercritical fluid is in a state of exceeding a critical temperature and a critical pressure peculiar to the substance, has a property intermediate between a gas and a liquid, and dissolves the substance like a liquid. It acts as a solvent. Since the dissolving power can be easily changed by changing the operating conditions such as the temperature and pressure of the supercritical fluid, it is possible to selectively extract a specific component according to the operating conditions such as temperature and pressure. It can be used in a supercritical chromatograph or a supercritical extraction tank.

Supercritical fluids include ethane, propane,
Although ethylene or the like can be used, carbon dioxide is used in the fields of foods, fragrances, chemicals and the like. The carbon dioxide has a critical temperature of 304.1 [° K] and a critical pressure of 7.3 [MPa], not only has a critical point at a position where it is relatively easy to handle, but is also nontoxic and inert. At the same time, it has unique transport properties in the supercritical state and is inexpensive.

When pressurized at around room temperature, the carbon dioxide becomes supercritical and can be used as a non-toxic extraction solvent in this state. Also, when it is returned to normal pressure, it gasifies and does not remain in the product. FIG. 2 is a schematic diagram of a conventional monitoring device in a supercritical chromatograph.

In the figure, reference numeral 51 is a thermostatic bath, and a bath main body 52, a residual heat coil 53 connected to the bath main body 52, a separation column 54 and a sample loop 55 are arranged in the thermostatic bath 51. A supercritical state due to carbon dioxide is formed in the tank body 52. Carbon dioxide in a supercritical state (hereinafter referred to as "supercritical fluid") extracts a specific component from a product.

Reference numeral 57 denotes a cylinder containing liquid carbon dioxide,
59 is a product container for containing a product containing various components, 6
1 is a residual heat coil 5 for the liquid carbon dioxide in the cylinder 57.
3 is a pump for supplying to. The pump 61 is cooled by a cooling medium from a cooler (not shown). Also, 6
3 is a pump for supplying the product in the product container 59 to the tank main body 52.

A pressure gauge 64 is provided in a line for supplying liquid carbon dioxide to the residual heat coil 53 by the pump 61, and a safety valve (not shown) is connected to the pressure gauge 64. Also, 81 is UV used for online monitoring
A detector (ultraviolet absorptiometer), 82 is a monitor, 83 is a three-way valve, 84 and 86 are pressure regulating valves for adjusting the pressure to a set value, 85 and 87 are recovery containers, and 89 is a gas meter.
The carbon dioxide gasified in the recovery containers 85 and 87 is exhausted from the gas meter 89.

In the supercritical chromatograph having the above-mentioned structure, the temperature of the liquid carbon dioxide supplied from the cylinder 57 is controlled by the tank body 52 in the constant temperature layer 51, and the pressure regulating valves 84 and 8 are used.
The pressure is adjusted by 6 to become a supercritical fluid, which is mixed with the product supplied from the product container 59. The supercritical fluid extracts and dissolves the components in the product in the tank body 52. The supercritical fluid in which the extracted components are dissolved is supplied to the separation column 54 when it exits the tank body 52.

The separation column 54 has an adsorbent such as silica gel as a fixed bed and the supercritical fluid as a moving bed. Then, the supercritical fluid supplied to the inlet is separated into each dissolved component while passing through the separation column 54, and is eluted from the outlet. That is, each component dissolved in the supercritical fluid reaches the outlet of the separation column 54 at different times because the adsorption power for the adsorbent and the dissolution power for the supercritical fluid are different from each other. Therefore, by collecting the supercritical fluid in time with the elution of the supercritical fluid in which each component is dissolved,
Specific ingredients within the product can be sorted.

In this case, it is necessary to constantly monitor which component is dissolved in the supercritical fluid eluted from the outlet of the separation column 54, and therefore a monitoring device is provided. Therefore, a UV detector 81 is connected to the outlet side of the separation column 54, and the component dissolved in the supercritical fluid eluted from the outlet is detected by the UV detector 81 and can be monitored by the monitor 82. .
The supercritical fluid discharged from the UV detector 81 is the three-way valve 8
3 and is decompressed by the pressure regulating valves 84 and 86 to become normal pressure, and becomes a gas-liquid two-phase fluid, and the recovery container 8
Recovered at 5,87. At this time, the components dissolved in the gas-liquid two-phase fluid are deposited and collected in the collection containers 85 and 87.

[0011]

However, in the conventional monitoring device, the UV detector 81 continuously detects the component dissolved in the eluted supercritical fluid, and the monitor 82 monitors the component online. However, since the supercritical chromatograph is performed under high pressure, it is necessary to increase the pressure resistance of the UV detector 81.

Although it is possible to manufacture a cell having a high pressure resistance in the UV detector 81, a solvent having a high UV absorptivity such as acetone is used for separating the supercritical fluid for each component in the supercritical chromatograph. When is used as a modifier, the background of the detection signal of the UV detector 81 becomes large and the measurement becomes difficult. Therefore, it is conceivable that after decompressing the supercritical fluid taken out from the separation column 54, an RI detector (differential refractometer) or a fluorescence detector is used to detect the components dissolved in the supercritical fluid. Gases such as carbon dioxide dissolved in the modifier become bubbles during depressurization, which makes measurement difficult. In such a case, the decompressed supercritical fluid is analyzed off-line by a gas chromatograph or the like.

However, in the off-line analysis, it takes time until the analysis result is obtained after sampling the supercritical fluid, and especially in the supercritical chromatograph, the preparative timing may be lost. It is an object of the present invention to provide a monitoring device that solves the problems of the conventional monitoring device described above and that is capable of detecting the components extracted and separated in a supercritical state online.

[0014]

Therefore, in the monitoring device of the present invention, a supercritical fluid is brought into contact with the contained product to dissolve the components in the product into the supercritical fluid, and the container is taken out from the bath. It also has a pressure control valve for reducing the pressure of the supercritical fluid to a gas-liquid two-phase fluid, and a pretreatment tank for accommodating the gas-liquid two-phase fluid in a substantially atmospheric pressure state.

The pretreatment tank has a degassing means for degassing the sample liquid and a means for keeping the level of the sample liquid constant. A detector is connected to the pretreatment tank, receives the sample liquid from the pretreatment tank, and detects the components in the sample liquid.
A circulation means is provided for returning the sample liquid of the detector to the pretreatment tank.

Further, a solvent for dissolving the components precipitated during depressurization may be supplied to the pretreatment tank.

[0017]

According to the present invention, as described above, the monitoring device is provided with a tank for bringing the contained product into contact with the supercritical fluid to dissolve the components in the product into the supercritical fluid, and the container is taken out from the tank. The supercritical fluid is decompressed by the pressure control valve to become a gas-liquid two-phase fluid. The gas-liquid two-phase fluid is supplied to the pretreatment tank and is housed at a substantially atmospheric pressure.

In the pretreatment tank, the sample liquid is degassed by the degassing means and the supersaturated gas is purged.
Further, the level of the sample liquid is kept constant, the supplied gas-liquid two-phase fluid is prevented from directly contacting the sample liquid, and bubbles are prevented from being generated in the sample liquid. A detector is connected to the pretreatment tank, receives the sample liquid from the pretreatment tank, and detects the components in the sample liquid. Then, the sample liquid after the detection is returned to the pretreatment tank.

Further, a solvent for dissolving the components precipitated during depressurization may be supplied to the pretreatment tank.

[0020]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a schematic diagram of a supercritical chromatograph to which a monitoring device according to an embodiment of the present invention is applied. In the figure, reference numeral 51 is a thermostatic bath, and a bath main body 52, a residual heat coil 53 connected to the bath main body 52, a separation column 54, and a sample loop 55 are arranged in the thermostatic bath 51. A supercritical state due to carbon dioxide is formed in the tank body 52.

57 is a cylinder containing liquid carbon dioxide,
Reference numeral 58 is a modifier container for containing a modifier such as acetone, 59 is a product container for containing a product containing a predetermined component, and 61 is a pump for supplying the liquid carbon dioxide in the cylinder 57 to the residual heat coil 53. The pump 6
1 is cooled by a cooling medium from a cooler (not shown). Further, 62 is a pump for supplying the modifier in the modifier container 58 to the tank main body 52, 63
Is a pump for supplying the product in the product container 59 to the tank main body 52.

A line for supplying liquid carbon dioxide to the residual heat coil 53 by the pump 61, and the pump 62.
The pressure gauges 64 and 65 are arranged in the line for supplying the modifier to the residual heat coil 53, and a safety valve (not shown) is connected to the line. Further, 66 is a preheating coil 5 for selectively selecting the liquid carbon dioxide and the modifier.
It is a three-way valve for supplying to No. 3.

Further, 21 is a pressure regulating valve for regulating the pressure of the supercritical fluid eluted from the outlet of the separation column 54 to reduce the pressure to a gas-liquid two-phase fluid, and 20 is an outlet of the separation column 54. A monitor unit used to monitor the eluted supercritical fluid online, 83 is a three-way valve for branching and supplying the gas-liquid two-phase fluid from the pressure regulating valve 21 for each dissolved component, 84, 86 is a pressure regulating valve for adjusting the pressure to a set value, 85 is a recovery container for precipitating the first component from the gas-liquid two-phase fluid, and 87 is a second container from the gas-liquid two-phase fluid.
The numeral 89 is a gas meter for collecting the components of the above. The carbon dioxide gas separated in the recovery containers 85 and 87 is exhausted from the gas meter 89.

In the supercritical chromatograph having the above structure, the liquid carbon dioxide supplied from the cylinder 57 has a temperature controlled by the tank body 52 in the thermostatic layer 51, and the pressure regulating valves 84, 8 are used.
6, the pressure is adjusted to a supercritical fluid, and the product and modifier container 58 supplied from the product container 59
It is mixed with the modifier supplied by. The supercritical fluid extracts components contained in the product in the tank body 52 and dissolves them in the supercritical fluid. The supercritical fluid in which the extracted components and the modifier are dissolved is supplied to the separation column 54 when exiting from the tank main body 52.

The separation column 54 has an adsorbent such as silica gel as a fixed bed and the supercritical fluid as a moving bed. Then, the supercritical fluid supplied to the inlet is separated into each dissolved component while passing through the separation column 54, and is eluted from the outlet. That is, each component dissolved in the supercritical fluid reaches the outlet of the separation column 54 at different times because the adsorption power for the adsorbent and the dissolution power for the supercritical fluid are different from each other. Therefore, by collecting the supercritical fluid at the timing of elution of the supercritical fluid in which each component and the modifier are dissolved, the specific component in the product can be separated.

In this case, it is necessary to constantly monitor which component is dissolved in the supercritical fluid eluted from the outlet of the separation column 54. Therefore, the pressure adjusting valve 21 is provided to reduce the pressure of the supercritical fluid. To form a gas-liquid two-phase fluid, and the gas-liquid two-phase fluid is supplied to the monitor unit 20. On the other hand, the three-way valve 83 is switched based on the monitoring result of the monitor unit 20, the gas-liquid two-phase fluid is branched, and is recovered in the recovery containers 85 and 87 via the pressure regulating valves 84 and 86. The components dissolved in the gas-liquid two-phase fluid in the recovery containers 85 and 87 are precipitated and collected in the recovery containers 85 and 87.

Next, the monitor section 20 will be described. FIG. 3 is a configuration diagram of a monitor unit in the monitoring device showing the embodiment of the present invention. In the figure, 21 is a pressure regulating valve for regulating the pressure of the supercritical fluid eluted from the separation column 54 (FIG. 1) and reducing it to a gas-liquid two-phase fluid,
Reference numeral 25 is a line for supplying the gas-liquid two-phase fluid to a separation unit (not shown). The extracted component and modifier are dissolved in the gas-liquid two-phase fluid.

The pressure regulating valve 2 in the line 25
A branch pipe 26 is connected between 1 and the sorting section. The branch pipe 26
Has a sample flow rate control valve 33 and is inserted into the pretreatment bath 34. Therefore, the flow rate of the gas-liquid two-phase fluid in which the components extracted from the branch pipe 26 and the modifier and the modifier are dissolved is adjusted by the sample flow rate control valve 33 and supplied to the pretreatment tank 34.

The pretreatment tank 34 is connected to a helium gas supply source, and the helium gas is supplied through a helium gas flow rate control valve 35, and the pretreatment tank 3 is supplied from an air diffuser 36.
4 is injected. An exhaust pipe 37 is provided in the pretreatment tank 34.
Is attached, the carbon dioxide and the helium gas which have been gasified are released from the pretreatment tank 34 to the atmosphere, and the pressure in the pretreatment tank 34 becomes almost atmospheric pressure. At this time, the sample liquid in which the extracted components and the modifier are dissolved remains in the pretreatment tank 34. Further, an overflow pipe 38 is attached to the pretreatment bath 34, and
The level of the sample liquid in 4 is kept constant. Then, the overflowed sample liquid is stored in the overflow storage tank 40.

On the other hand, the sample liquid in the pretreatment tank 34 is extracted from the pretreatment tank 34 by the sample withdrawing pump 41 and sent to the detector 43 via the degasser 42. In the detector 43, the sample liquid is analyzed,
The component dissolved in the sample liquid can be detected.
When the detection is completed by the detector 43, the sample liquid is returned to the pretreatment tank 34 through the recycle pipe 44.

A solvent tank 45 may be provided if necessary, and the solvent 46 in the solvent tank 45 may be supplied to the pretreatment tank 34 by a solvent pump 47. Next, the operation of the monitoring device having the above configuration will be described. The supercritical fluid in which the extracted components and the modifier are dissolved is decompressed by the pressure control valve 21, and changes from the one-phase state of the supercritical state to the gas-liquid two-phase fluid.

A part of the gas-liquid two-phase fluid is sampled by the branch pipe 26, and the sampling amount is adjusted by the sample flow rate control valve 33 to the minimum amount required for monitoring. Then, the gas-liquid two-phase fluid is introduced into the pretreatment tank 34, becomes a state of substantially atmospheric pressure, and is completely separated into a gas phase and a liquid phase, and the liquid phase portion becomes a sample liquid. By the way, in addition to the above components and modifiers, carbon dioxide used as a supercritical fluid is dissolved in the sample liquid in a supersaturated state. If the sample liquid is supplied to the detector 43 as it is, bubbles of carbon dioxide are generated in the detector 43, which makes it difficult to detect the components.

Therefore, helium gas is supplied to the sample liquid via the helium gas flow rate control valve 35 and the diffuser pipe 36 to purge supersaturated carbon dioxide and stir the sample liquid. The gasified carbon dioxide and helium gas are released to the outside through the exhaust pipe 37. The sample liquid from which supersaturated carbon dioxide has been purged is sent to the detector 43 by the sample withdrawing pump 41, and the components are analyzed. At this time, if further degassing is required, a degasser 42 is arranged between the sample withdrawing pump 41 and the detector 43 to degas the sample liquid.

The sample liquid discharged from the detector 43 is returned to the pretreatment tank 34 via the recycle pipe 44. As a result, the sample liquid in the pretreatment tank 34 is stirred, and the liquid level in the pretreatment tank 34 is changed by the unbalance between the flow rate of the supercritical fluid sampled through the branch pipe 26 and the flow rate of the sample extraction pump 41. It prevents the gas from lowering or gas from flowing into the sample extraction pump 41.

Further, since the overflow pipe 38 is attached to the pretreatment tank 34, the level of the sample liquid does not become higher than the position of the overflow pipe 38, and the gas-liquid two sampled by the branch pipe 26 is used. It prevents the phase fluid from coming into direct contact with the sample liquid and generating bubbles in the sample liquid. Although the overflowed sample liquid is normally stored in the overflow storage tank 40, it can be obtained as an extraction component or a preparative component.

Further, when the components extracted by the pressure reduction in the pressure control valve 21 are precipitated and become solid, the solvent 46 is used to remove the solvent 46 by the pretreatment tank 3
4 is supplied in an appropriate amount to dissolve the above components. In this way, the detection by the detector 43 becomes possible. The monitoring device configured as described above can also detect the components extracted by the supercritical extraction device.

For example, when a solvent such as acetone, methanol, or ethanol used in the manufacturing process of pharmaceuticals remains in the product, the solvent is extracted to a low level without impairing the quality of the product to improve the quality of the product. There is a need. When this is extracted by a vacuum heating method, when a product having high heat sensitivity is processed, the quality of the product deteriorates with heating. Moreover, extraction by a humidification desolvation method not only requires drying the product after humidification, but is not suitable for treating a product that is unstable to moisture.

Therefore, a supercritical extraction apparatus for extracting a solvent at low temperature without using water will be described. FIG. 4 is a schematic diagram of a supercritical fluid extraction device to which a monitoring device according to an embodiment of the present invention is applied. In the figure, 11 is an extraction tank, and 11a is an extraction tank main body. The capacity of the extraction tank main body 11a is 1200 [L], and the product is stored therein. The product is a fine powder having a particle size of about 10 [μ], and the amount of acetone used in the manufacturing process is 2 to 5
〔%〕contains. Reference numeral 12 is a stirring member arranged in the extraction tank main body 11a, which is rotated by a motor 13 to stir the product.

15 is a storage tank for storing liquid carbon dioxide, 1
6 is a high-pressure pump and 17 is a heater. The liquid carbon dioxide in the storage tank 15 is pressurized to a predetermined pressure by the high-pressure pump 16, heated to a predetermined temperature in the heater 17, and then sent to the extraction tank 11 as an extraction solvent. Also,
The modifier is supplied to the extraction tank 11 from a modifier container (not shown).

In the extraction tank 11, the product, modifier and extraction solvent are placed in a supercritical state where the critical pressure is 9.8 [MPa] or more and the critical temperature is 313 [° K],
Be stirred. As a result, the acetone in the product is extracted by the supercritical fluid, and the remaining acetone is 500 [PP
M] or less. After that, the pressure of the supercritical fluid after the solvent is extracted is adjusted by the pressure adjusting valve 21, heated by the heater 22, and then flows out of the system.

In addition to liquid carbon dioxide, nitrogen gas is supplied to the extraction tank 11. The nitrogen gas is heated by the heater 24 and then supplied to the extraction tank 11. The line between the pressure regulating valve 21 and the heater 22 is branched to connect the monitor unit 20. Also in this case, the components extracted from the product can be monitored online in the monitor unit 20.

The present invention is not limited to the above-mentioned embodiments, but various modifications can be made based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

[0043]

As described in detail above, according to the present invention, the monitoring device is provided with the tank for bringing the contained product into contact with the supercritical fluid to dissolve the components in the product into the supercritical fluid. The supercritical fluid taken out from the tank is decompressed by the pressure control valve to become a gas-liquid two-phase fluid. The gas-liquid two-phase fluid is supplied to the pretreatment tank and is housed at a substantially atmospheric pressure.

In the pretreatment tank, the sample liquid is degassed by the degassing means to make the level constant. Therefore, it is possible to prevent the gas-liquid two-phase fluid supplied to the pretreatment tank from coming into direct contact with the sample liquid, and prevent bubbles from being generated in the sample liquid. A detector is connected to the pretreatment tank, receives the sample liquid from the pretreatment tank, and detects the components in the sample liquid. Then, the sample liquid after the detection is returned to the pretreatment tank.

Therefore, it is possible to stir the sample liquid in the pretreatment tank and prevent the liquid level in the pretreatment tank from being lowered, and to prevent the gas from being supplied to the detector together with the sample liquid. Further, since the sample liquid in the detector is sufficiently degassed, it becomes possible to detect the components separated from the product online.

[Brief description of drawings]

FIG. 1 is a schematic view of a supercritical chromatograph to which a monitoring device according to an embodiment of the present invention is applied.

FIG. 2 is a schematic view of a monitoring device in a conventional supercritical chromatograph.

FIG. 3 is a configuration diagram of a monitor unit in the monitoring device according to the embodiment of the present invention.

FIG. 4 is a schematic diagram of a supercritical fluid extraction device to which a monitoring device according to an embodiment of the present invention is applied.

[Explanation of symbols] 11 extraction tank 21 pressure control valve 34 pretreatment tank 38 overflow pipe 43 detector 44 recycling pipe 46 solvent 47 solvent pump 51 room temperature tank

Claims (2)

[Claims] 1. A tank for (a) bringing a supercritical fluid into contact with a contained product to dissolve the components in the product into the supercritical fluid; and (b) depressurizing the supercritical fluid taken out from the tank to vaporize the product. A pressure control valve for a liquid two-phase fluid; (c) a pretreatment tank for accommodating the gas-liquid two-phase fluid at substantially atmospheric pressure; and (d) a degassing for degassing the sample liquid in the pretreatment tank. Means, (e) means for making the level of the sample liquid in the pretreatment tank constant, (f) a detector for receiving the sample liquid from the pretreatment tank and detecting a component in the sample liquid, g) A monitoring device having a circulation means for returning the sample liquid of the detector to the pretreatment tank. 2. The monitoring device according to claim 1, further comprising a means for supplying a solvent for dissolving the components precipitated during depressurization to the pretreatment tank.