Patent Publication Number: US-2019184319-A1

Title: Fluid processing device and processing liquid recovery method

Description:
TECHNICAL FIELD 
     The present invention relates to a fluid processing system including a super-critical fluid system that performs separation or extraction of a sample component by using a super-critical fluid, a flow synthesis system that performs flow synthesis, which is synthesis of a predetermined compound, by flowing a liquid including a raw material through at least one column to thereby cause a reaction, and relates to a processed liquid collecting method for collecting the liquid having gone through the process in the fluid processing system as a processed liquid. 
     BACKGROUND ART 
     In a super-critical fluid chromatograph (SFC) or a super-critical fluid extraction (SFE) system, for example, a mixed fluid of carbon dioxide and modifier is delivered as a mobile phase through an analytical channel. A back pressure valve for regulating a pressure in the analytical channel is provided to the analytical channel and regulates the pressure in the analytical channel so that the pressure becomes higher than or equal to 10 MPa (megapascals). In the analytical channel, carbon dioxide in the mobile phase flows in a super-critical fluid state or a liquid state. On a downstream of the back pressure valve, the pressure in the channel is normally at an atmospheric pressure. Therefore, a pressure of carbon dioxide after passing through the back pressure valve is reduced to the atmospheric pressure and carbon dioxide is vaporized. 
     In the SFC or the SFE system with a preparative function, a sample dissolved in the mixed fluid of carbon dioxide and the modifier is collected after passage through the back pressure valve. Because carbon dioxide increases 400-fold in volume when vaporized, the modifier is aerosolized in carbon dioxide, which is at a high linear velocity, and ejected from a pipe outlet with vaporized carbon dioxide. As a result, the modifier including the sample component is scattered and part of the sample component is lost. 
     To solve the problem, in general, a gas-liquid separator for separating fluid after passing through a back pressure valve into a gas phase (carbon dioxide) and a liquid phase (modifier which is mainly methanol) by spirally flowing the fluid along an edge of a container is provided (see Patent Documents 1, 2). The liquid phase separated from the gas phase by the gas-liquid separator is collected into a predetermined container. 
     PRIOR ART DOCUMENTS 
     Patent Documents 
     Patent Document 1: Japanese Patent Application Laid-open National Publication No. 2009-544042 
     Patent Document 2: Japanese Patent Application Laid-open Publication No. 2010-78532 
     Patent Document 3: Japanese Patent Application Laid-open Publication No. 2015-172025 
     SUMMARY OF THE INVENTION 
     Problems to be Solved by the Invention 
     Even if the above-described gas-liquid separator is provided, the liquid phase is ejected from the pipe outlet with vaporized carbon dioxide. Therefore, the liquid phase is scattered by carbon dioxide to thereby cause reduction in collection rate and contamination of multiple analysis components. Moreover, if the gas-liquid separator is provided on an upstream of a collecting container, the liquid phase ejected from the pipe outlet is likely to remain in the gas-liquid separator and the remaining liquid phase can cause the contamination and, as a result, it is necessary to clean the gas-liquid separator for each analysis. Therefore, a structure for easily performing the gas-liquid separation without ejecting the fluid is desired. 
     In a field of flow synthesis for forming useful molecules such as a pharmaceutical drug by flowing row material into a column in stages while causing a reaction, a process for removing a gas phase, included in liquid including a product, and collecting only a liquid phase may be performed in some cases (see Patent Document 3). In this case, a structure with which the gas phase can be easily removed from fluid in a flow of process for the flow synthesis is preferable. 
     Therefore, it is an object of the present invention to easily collect a liquid phase while removing a gas phase from fluid including the gas phase and the liquid phase after going through a predetermined process in fields of analysis and extraction by use of super-critical fluid, flow synthesis, and the like. 
     Solutions to the Problems 
     According to an aspect of the present invention, a fluid processing system is provided including: 
     a fluid processing section that performs a process for analysis or extraction of a component or synthesis while flowing fluid through a channel, the fluid which flows out from the fluid processing section includes a gas phase and a liquid phase; 
     a gas-liquid separation section connected to a downstream of the fluid processing section, the gas-liquid separation section comprises a gas-liquid separation pipe formed by material which allows gas through and does not allow liquid through, and the liquid phase from the gas phase is separated by discharging the gas phase in the fluid flowing through the gas-liquid separation pipe to an outside of the gas-liquid separation pipe through a wall face of the gas-liquid separation pipe; and 
     a liquid phase collecting section provided on a downstream of the gas-liquid separation section and collects the liquid phase separated from the gas phase in the gas-liquid separation section. 
     The fluid processing system according to the aspect of the invention may be a super-critical fluid system that performs separation or extraction of a sample component by using super-critical fluid. In this case, the fluid processing section includes a mobile phase delivery channel through which mixed fluid of carbon dioxide and modifier is delivered as a mobile phase and a back pressure valve that regulates a pressure in the mobile phase delivery channel so as to keep the mobile phase in a super-critical state in the mobile phase delivery channel. 
     The fluid processing system according to the aspect of the invention may be a flow synthesis system for performing flow synthesis which is synthesis of a predetermined compound by flowing liquid including a raw material through at least one column to thereby cause a reaction. 
     The gas-liquid separation section may include a pressurization section that maintains an inside of the gas-liquid separation pipe at a pressure higher than an atmospheric pressure. In this way, it is possible to more efficiently discharge the gas phase in the fluid flowing through the gas-liquid separation pipe to the outside of the gas-liquid separation pipe. 
     As a structure embodying the pressurization section, a channel segment having a smaller inside diameter than the gas-liquid separation pipe may be provided to a downstream end downstream end of the gas-liquid separation pipe or on a downstream of the downstream end of the gas-liquid separation pipe. This structure simplifies a structure of the gas-liquid separation section and reduces cost. 
     As another structure embodying the pressurization section, a pressure regulating valve, that regulates a pressure in the gas-liquid separation pipe so that the pressure becomes a predetermined pressure higher than the atmospheric pressure, may be provided on a downstream of the gas-liquid separation pipe. With the pressure regulating valve, it is possible to reliably obtain the pressure necessary for discharging the gas phase in the fluid flowing through the gas-liquid separation pipe from the gas-liquid separation pipe to thereby more reliably realize the gas-liquid separation in the gas-liquid separation section. 
     The gas-liquid separation section may include a pressure reducing mechanism that reduces a pressure around the gas-liquid separation pipe to a pressure lower than a pressure in the gas-liquid separation pipe. The pressure reducing mechanism may be provided instead of or in addition to the pressurization section. It is possible to facilitate the discharge of the gas phase in the fluid flowing through the gas-liquid separation pipe from the gas-liquid separation pipe not only by increasing the pressure in the gas-liquid separation pipe but also by reducing the pressure around the gas-liquid separation pipe. 
     An example of the material of the gas-liquid separation pipe is polytetrafluoroethylene. 
     According to another an aspect of the invention, a processed liquid collecting method is provided including the steps of: introducing fluid, including a gas phase and a liquid phase and after passage through a fluid processing section, into a gas-liquid separation pipe made of material which allows gas through and does not allow liquid through, the fluid processing section performing a treatment of a sample while flowing the fluid through a channel; separating the liquid phase from the gas phase by discharging the gas phase included in the fluid flowing through the gas-liquid separation pipe to an outside of the gas-liquid separation pipe through a wall face of the gas-liquid separation pipe; and recovering the liquid phase separated from the gas phase through the gas-liquid separation pipe as processed liquid. 
     Effects of the Invention 
     The fluid processing system according to the aspect of the invention is provided, on the downstream of the fluid processing section that performs the treatment of the sample while flowing the fluid through the channel, with the gas-liquid separation section that includes the gas-liquid separation pipe made of the material letting the gas through and not letting the liquid through, and that separates the gas phase in the fluid flowing through the gas-liquid separation pipe from the liquid phase by discharging the gas phase to the outside of the gas-liquid separation pipe through the wall face of the gas-liquid separation pipe. Therefore, it is possible to easily remove the gas phase from the fluid after passage through the fluid processing section. In this way, it is possible to easily and highly efficiently recover the liquid phase in the fluid after the passage through the fluid processing section. Moreover, a gas-liquid separator used in the prior art is unnecessary, which simplifies the structure and avoids scattering of the liquid phase from the pipe outlet. Therefore, the scattered liquid does not remain in the gas-liquid separator, and the gas-liquid separator does not need cleaning for every analysis unlike in the case of the prior-art gas-liquid separator. 
     The processed liquid collecting method according to the aspect of the invention removes the gas phase while flowing the fluid after passage through the fluid processing section through the channel and recovers the liquid phase separated from the gas phase as the processed liquid. Therefore, it is possible to easily and highly efficiently recover the liquid phase in the fluid after the passage through the fluid processing section. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a channel structure diagram schematically showing an embodiment of a super-critical fluid chromatograph. 
         FIG. 2  is a structure diagram schematically showing an example of a structure of a gas-liquid separator. 
         FIG. 3  is a structure diagram schematically showing another example of the structure of the gas-liquid separator. 
         FIG. 4  is a structure diagram schematically showing yet another example of the structure of the gas-liquid separator. 
     
    
    
     EMBODIMENT OF THE INVENTION 
     An embodiment of a fluid processing system according to the present invention will be described below by using the drawings. 
     An embodiment of a super-critical fluid system which is one of the fluid processing systems is shown in  FIG. 1 . 
     The super-critical fluid system according to the embodiment includes a fluid processing section  1  for performing an analytical process of components while flowing fluid through a channel, a gas-liquid separation section  24 , and a liquid phase collecting section  27 . The fluid processing section  1  includes a mobile phase delivery channel  2 , a sample injection section  14 , an analytical column  16 , a detector  20 , and a back pressure valve  22 . The sample injection section  14 , the analytical column  16 , and the detector  20  are provided on the mobile phase delivery channel  2  in this order from an upstream. The back pressure valve  22  is connected to a downstream end of the mobile phase delivery channel  2 . 
     The gas-liquid separation section  24  is provided on a downstream of the back pressure valve  22  and the liquid phase collecting section  27  is provided on a downstream of the gas-liquid separation section  24 . The liquid phase collecting section  27  includes a channel switching valve  28  connected to the downstream of the gas-liquid separation section  24  and a plurality of collecting containers  30   a  to  30   d  connected to respective ports of the channel switching valve  28 . Although the four collecting containers  30   a  to  30   d  are shown in the embodiment, any number of collecting containers may be provided. 
     On an upstream of the mobile phase delivery channel  2 , delivery pumps  8 ,  10  for respectively delivering carbon dioxide and modifier in liquid states and a mixer  12  for mixing the carbon dioxide and the modifier are provided. Carbon dioxide delivered from a carbon dioxide cylinder  4  by the delivery pump  8  and the modifier delivered from a modifier container  6  by the delivery pump  10  are mixed by the mixer  12  to become mixed fluid and flows through the mobile phase delivery channel  2  as a mobile phase. 
     The back pressure valve  22  is controlled so that a pressure in the mobile phase delivery channel  2  becomes a predetermined pressure (e.g., 10 MPa). In this way, carbon dioxide in the mobile phase flows in a super-critical state through the mobile phase delivery channel  2 . 
     A sample to be analyzed is introduced into the mobile phase delivery channel  2  by the sample injection section  14 . The analytical column  16  is connected to a downstream of the sample injection section  14  and the sample introduced into the mobile phase delivery channel  2  via the sample injection section  14  is separated into the components in the analytical column  16 . The analytical column  16  is housed in a column oven  18  and a temperature of the analytical column  16  is kept constant. The detector  20  is connected to a downstream of the analytical column  16  and the sample components eluted from the analytical column  16  are consecutively introduced into the detector  20 . 
     The back pressure valve  22  is connected to a downstream of the detector  20  and the gas-liquid separation section  24  is provided on an outlet side of the back pressure valve  22 . The gas-liquid separation section  24  includes a gas-liquid separation pipe  26 . The gas-liquid separation pipe  26  is a pipe formed by material which allows gas through and does not allow liquid through. An example of the material of the gas-liquid separation pipe is PTFE (polytetrafluoroethylene). The gas-liquid separation section  24  separates the fluid flowing out of the outlet of the back pressure valve  22  into the gas phase and the liquid phase by utilizing the gas-liquid separation pipe  26 . 
     Carbon dioxide in the fluid flowing out of the outlet of the back pressure valve  22  is vaporized to be the gas phase due to rapid reduction in pressure. On the other hand, the modifier is in the liquid state before and after the back pressure valve  22 . Almost entire quantities of the sample components eluted from the analytical column  16  are dissolved in the modifier which is the liquid phase. The gas-liquid separation section  24  is formed to discharge carbon dioxide, which is the gas phase in the fluid flowing through the gas-liquid separation pipe  26 , to an outside of the gas-liquid separation pipe  26  and to lead only the liquid phase to the channel switching valve  28  provided on the downstream. 
     The channel switching valve  28  of the liquid phase collecting section  27  is a rotary switching valve, for example, and connects a channel from the gas-liquid separation section  24  to one of the collecting containers  30   a  to  30   d . The channel switching valve  28  switches the channel in synchronization with a detection signal from the detector  20 . and the liquid phases including the respective sample components separated in the analytical column  16  are collected in the separate collecting containers  30   a  to  30   d.    
     In the super-critical fluid system according to the embodiment, the gas phase is discharged to the outside of the channel in the gas-liquid separation section  24 , and therefore, only the liquid phases are dropped into the respective collecting containers  30   a  to  30   d . Thus, vaporized carbon dioxide is not ejected from an outlet of the pipe communicating with the collecting containers  30   a  to  30   d  and the liquid phases are not scattered. 
     It is possible to enhance efficiency of the gas-liquid separation section  24  in separating the fluid into the gas and the liquid by providing a pressurization section for increasing a pressure in the gas-liquid separation pipe  26 . 
     An example of the gas-liquid separation section  24  provided with the pressurization section is shown in  FIG. 2 . 
     In a structure in  FIG. 2 , a tubing  34  as the pressurization section is connected by a joint  32  to a downstream of the gas-liquid separation pipe  26 . The tubing  34  has a smaller inside diameter than the gas-liquid separation pipe  26  and maintains an inside of the gas-liquid separation pipe  26  at a pressure (e.g., 3 MPa) higher than an atmospheric pressure. Because the pressure in the gas-liquid separation pipe  26  is maintained at the pressure higher than the atmospheric pressure, discharge of the gas phase in the fluid flowing through the gas-liquid separation pipe  26  to the outside of the gas-liquid separation pipe  26  is facilitated and the efficiency in separating the fluid flowing out of the outlet of the back pressure valve  22  into the gas and the liquid is enhanced. 
     Another example of the structure of the gas-liquid separation section  24  provided with the pressurization section is shown in  FIG. 3 . 
     In a structure in  FIG. 3 , a pressure sensor  36  is provided on a downstream of a gas-liquid separation pipe  26  and a pressure control valve  38  as the pressurization section is provided on a downstream of the pressure sensor  36 . The pressure control valve  38  has a similar structure to the back pressure valve  22 , for example. Operation of the pressure control valve  38  is controlled by a control section  40 . The control section  40  controls the operation of the pressure control valve  38  based on a detection signal from the pressure sensor  36  so that a pressure in the gas-liquid separation pipe  26  becomes a pressure (e.g., 3 MPa) higher than an atmospheric pressure. The control section  40  may be used also as a control section for controlling operation of the back pressure valve  22 , for example, as shown in  FIG. 3 . 
     With the structure in  FIG. 3 , as with the structure in  FIG. 2 , discharge of a gas phase in fluid flowing through the gas-liquid separation pipe  26  to an outside of the gas-liquid separation pipe  26  is facilitated, and efficiency in separating the fluid flowing out of an outlet of the back pressure valve  22  into gas and liquid is enhanced. 
     The pressurization section is not limited to those shown in  FIGS. 2 and 3 . For example, the pressure section may be any structure such as a structure including an orifice section having a smaller inside diameter than the gas-liquid separation pipe  26  and provided to a downstream end of the gas-liquid separation pipe  26  or on a downstream of the downstream end of the gas-liquid separation pipe  26 , if the structure can maintain an inside of the gas-liquid separation pipe  26  at a pressure higher than an atmospheric pressure. 
     The efficiency of the gas-liquid separation section  24  in separating the fluid into the gas and the liquid is enhanced also by providing a pressure reducing section for reducing a pressure outside the gas-liquid separation pipe  26  instead of or in addition to the pressurization section. 
     An example of a structure of the gas-liquid separation section  24  provided with the pressure reducing section is shown in  FIG. 4 . 
     In a gas-liquid separation section  24  in this example, a gas-liquid separation pipe  26  is housed in a closed space  42 . An inside of the closed space  42  is reduced in pressure to a pressure lower than an atmospheric pressure by a vacuum pump. Because the pressure in the gas-liquid separation pipe  26  is the atmospheric pressure or a pressure close to the atmospheric pressure, a pressure in the gas-liquid separation pipe  26  becomes relatively higher than the pressure around the gas-liquid separation pipe  26  when the pressure in the closed space  42  is reduced to the pressure lower than the atmospheric pressure. As a result, discharge of a gas phase in fluid flowing through the gas-liquid separation pipe  26  to an outside of the gas-liquid separation pipe  26  is facilitated, and efficiency in separating the fluid flowing out of an outlet of a back pressure valve  22  into gas and liquid is enhanced. 
     Although the pressure in the gas-liquid separation pipe  26  is the atmospheric pressure or the pressure close to the atmospheric pressure in the example in  FIG. 4 , the pressurization section shown in  FIG. 2 or 3  may be used to increase the pressure in the gas-liquid separation pipe  26  to a pressure higher than the atmospheric pressure and the pressure reducing section shown in  FIG. 4  may be also used to reduce the pressure outside the gas-liquid separation pipe  26  to a pressure lower than the atmospheric pressure. In this way, the discharge of the gas phase in the fluid flowing through the gas-liquid separation pipe  26  to the outside of the gas-liquid separation pipe  26  is further facilitated, and the efficiency in separating the fluid flowing out of the outlet of the back pressure valve  22  into the gas and the liquid is further enhanced. 
     Although the fluid flowing out of the outlet of the back pressure valve  22  is separated into the gas and the liquid by the gas-liquid separation section  24  and then only the liquid phases are introduced into the respective collecting containers  30   a  to  30   d  via the channel switching valve  28  in the super-critical fluid system described by using  FIG. 1 , the invention is not limited to this structure. Similar effects to those of the above-described embodiment can be obtained also by connecting a channel switching valve  28  to the downstream of the back pressure valve  22  without interposing the gas-liquid separation section  24  therebetween and providing the gas-liquid separation sections  24  between the channel switching valve  28  and the respective collecting containers  30   a  to  30   d.    
     Although the super-critical fluid system described in the above embodiment is the super-critical fluid chromatograph for performing separation and analysis of the sample by using the super-critical fluid, the super-critical fluid system included in the embodiment is not limited to it. The system can be similarly applied to super-critical fluid extraction which is extraction of components included in a sample by use of super-critical fluid. 
     In addition to the above-described field of super-critical fluid, the invention can be similarly applied to the field of flow synthesis disclosed in Patent Document 3. In this case, as shown in  FIG. 5 , the above-described gas-liquid separation section  24  employing the gas-liquid separation pipe  26  can be used to remove a gas component (a gas phase) included in product liquid obtained in a final step of the flow synthesis section  46  (a fluid processing section) disclosed in Patent Document 3. A structure of the gas-liquid separation section  24  may be similar to those shown in  FIGS. 2 to 4 . 
     Although it is not shown in the figures, at least one column is provided on a channel through which liquid including raw material substances for synthesis flows in the flow synthesis section  46 . A solid phase such as a catalyst which reacts with the row material substances is retained in the column. By passing the liquid including the raw material substances through the column, a reaction necessary for the synthesis occurs during the passage of the liquid. The liquid including a substance produced in the flow synthesis section  46  is introduced into the gas-liquid separation section  24  and an unnecessary gas component is removed in the gas-liquid separation section  24 . The liquid phase after the removal of the unnecessary gas component in the gas-liquid separation section  24  is collected as processed liquid into a collecting container  48 . 
     DESCRIPTION OF REFERENCE SIGNS 
     
         
         
           
               1 ,  46 : Fluid processing section 
               2 : Mobile phase delivery channel 
               4 : Carbon dioxide cylinder 
               6 : Modifier container 
               8 ,  10 : Delivery pump 
               12 : Mixer 
               14 : Sample injection section 
               16 : Analytical column 
               18 : Column oven 
               20 : Detector 
               22 : Back pressure valve 
               24 : Gas-liquid separation section 
               26 : Gas-liquid separation pipe 
               27 : Liquid phase collecting section 
               28 : Channel switching valve 
               30   a  to  30   d ,  48 : Collecting container 
               32 : Joint 
               34 : Tubing 
               36 : Pressure sensor 
               38 : Pressure control valve 
               40 : Control section 
               42 : Closed space 
               44 : Vacuum pump