JP2009061422A - Manufacturing method of gas component and condensable component, and manufacturing apparatus thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a gas component and a condensable component which assures a desired product gas with a predetermined purity and a high recovering rate and capable of avoiding liquefaction of the condensable component in a primary side gas of a gas separation membrane with an universal and inexpensive method even at a high recovering rate, and to provide a manufacturing apparatus thereof. <P>SOLUTION: The manufacturing apparatus includes the gas separation membrane S having the selective permeability to the raw material gas containing a plurality of components and a first and a second gas-liquid separation part D1, D2 based on the difference in condensability of the components, and produces a permeation gas rich in the permeable and non-condensable component obtained from the gas separation membrane S, and the by-product gas reduced in the impermeable and condensable component and obtained from the first and second gas-liquid separation part. The apparatus is characterized by including a constituting element such as a circulation gas passage Fa for circulating part of at least the second by-product gas, a raw material gas passage Uo and the like. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method and apparatus for producing a gas component and a condensable component, and specifically uses a separation function of a gas separation membrane having selective permeability and a gas-liquid separation function based on a difference in condensation temperature of each component. The present invention relates to a gas component and a condensable component manufacturing method and a manufacturing apparatus for separating and recovering a specific component from a raw material gas including a plurality of components.

Conventionally, semiconductor manufacturing factories or various chemical process factories have required a predetermined amount of high-purity gas as a raw material gas or a processing gas in each process, and these gases are separated from readily available low-cost raw materials. Often used continuously. Specifically, for example, when obtaining either or both of enriched oxygen gas and enriched nitrogen gas from the air, when separating and concentrating hydrogen (H ₂ ) from the naphtha cracked gas, the organic substance from the gas mixture containing organic vapor For example, when vapor is separated and recovered, H ₂ is separated from water gas. In such a process, since the apparatus is small and simple, a gas mixture having different permeability is supplied as a raw material gas to a gas separation membrane having selective permeability, and separated into a permeated gas and a residual gas. In many cases, gas permeated gas is taken out as a product.

  In such a gas production method using a gas separation membrane, as shown in FIG. 9, a compressor 102, a dryer 108, a heater 109, a gas separation unit 103 provided with a gas separation membrane 101, a residual pressure regulating valve. 110, cooler 113 Based on a system including a permeate pressure regulating valve 111, various configurations according to a desired application and specifications have been used (for example, see Patent Document 1).

  For example, when a relatively high pressure hydrogen gas product and a relatively low pressure hydrogen gas product are required, it is well known that a cascade cycle as shown in FIG. 10 is effective. In this example, two sets of gas separation membranes 201 (first gas separation membrane 201a and second gas separation membrane 201b) are used in combination. In this structure, the source gas g1 merges with the permeable gas g2aa of the second gas separation membrane 201b, and is supplied to the first gas separation membrane 201a after being compressed. In this state, a permeable gas g2a is produced by the first gas separation membrane 201a, and the residual gas g2b is supplied as a source gas for the second gas separation membrane 201b. In the second gas separation membrane 201b, residual gas is produced. Then, the permeable gas g2aa is reused by merging with the original source gas (see, for example, Patent Document 1). Here, in FIG. 10, the permeable gas g2aa from the second gas separation membrane 201b is illustrated as being reused. However, the permeable gas g2a is taken out as a high-pressure product gas, and the permeable gas g2aa is reduced to a low pressure. It can be taken out as product gas.

  Moreover, as a parallel cycle, the system which isolate | separates and collects enriched nitrogen gas from the air which is illustrated in FIG. 11 can be mentioned. In FIG. 11, two hollow fiber separation membrane modules 312 and 313 are used in parallel, and the supply gas branches after the pretreatment and is supplied to each of the modules 312 and 313. The enriched nitrogen gas obtained in the membrane modules 312, 313 merges and is led to the product gas outlet 324. Air collected from the air intake port 301 is supplied with air to the compressor 303 after removing suspended particles in the air by the dust filter 302. The pressurized air flows from the gas supply ports of the hollow fiber gas separation membrane modules 312, 313 to the membrane supply side. The permeated gas that has permeated flows through the permeate side of the membrane and becomes a permeated gas exhaust flow through the permeate gas discharge port of the module. (See, for example, Patent Document 2). Here, in the system of FIG. 11, the case where the enriched nitrogen gas is recovered as the product gas is shown, but the permeate gas discharge flow is the enriched oxygen gas, and this can also be recovered as the product gas. is there. At this time, by independently adjusting the pressure and flow rate of the air supplied to the parallel hollow fiber separation membrane modules 312, 313, one permeable gas is taken out as a high pressure product gas, and the other permeable gas is taken as a low pressure. It can be taken out as product gas.

JP 2000-33222 A JP 2002-35530 A

When gas is produced using a gas separation membrane, product purity and recovery are the main characteristics. In general, the required purity is determined according to the application of the product gas, and the control method including the process and weight reduction operation is determined by examining the policy of ensuring the recovery rate as much as possible within that range. However, some problems may occur with a raw material gas containing a plurality of components including a hardly permeable and condensable component depending on the system or method.
(I) Since alteration of the membrane itself may occur, it is necessary to avoid generation of mist in the gas on the primary side of the membrane. More specifically, when a condensable component is contained in the raw material gas, liquefaction may occur at room temperature. When this condensable component is a hardly permeable gas, gas separation proceeds according to the progress of gas separation. Since the condensable components may concentrate and liquefy in the gas on the primary side (non-permeate side) of the membrane, for example, the raw material gas is cooled to about 40 ° C (summer outdoor air conditions) to separate the condensed liquefied components. Thereafter, it was necessary to avoid the risk of generating liquid mist on the gas separation membrane by heating with a heating means.
(Ii) However, since there is a limit to the heating temperature due to the separation characteristics of the gas separation membrane and the high-temperature resistance, when attempting to increase the recovery rate of the desired component of the permeate gas (hereinafter referred to as “recovery rate”) Since there is a possibility that the condensable component is liquefied in the gas on the primary side of the membrane, measures have been taken to limit the recovery rate or reduce the primary pressure of the gas separation membrane to avoid liquefaction.
In the present invention, attention is paid to avoiding liquefaction associated with concentration of condensable components in the gas on the primary side of the gas separation membrane. As the permeation progresses, the condensation of the condensable component proceeds, so that the gas at the residual gas outlet (nearest) is most easily liquefied. Therefore, the dew point under the pressure of the gas at the residual gas outlet is important, and if the dew point is lower than the gas temperature at the gas separation membrane, liquefaction will not occur in the gas on the primary side of the gas separation membrane. Become. In practice, it is desirable to operate by setting a reference value for the dew point slightly lower (for example, 10 ° C.) than the gas temperature of the gas separation membrane in consideration of fluctuations in the raw material gas composition and operating conditions. Hereinafter, the pressure immediately after the residual gas outlet of the gas separation membrane is referred to as “residual gas pressure”, the dew point under the residual gas pressure immediately after the residual gas flow path outlet of the gas separation membrane is “residual gas dew point”, and the residual gas separation membrane The gas flow rate is referred to as “residual gas flow rate”, and the permeate gas pressure and flow rate are referred to as “permeate gas pressure” and “permeate gas flow rate”.

  An object of the present invention is to ensure a desired product gas and a condensable component having a desired purity and recovery rate when recovering a gas component and a condensable component from a raw material gas containing a plurality of components, and efficiently and Gas component and condensable component manufacturing method and apparatus capable of avoiding liquefaction of condensable component in gas on the primary side of the gas separation membrane with a general technique, even for a high recovery rate Is to provide. In particular, it is intended to obtain a further recovery rate during the weight reduction operation. In the present application, when simply referred to as “recovery rate”, it means the ratio of the total flow rate of the desired component (easy-permeable gas) in the product gas to the flow rate of the desired component in the raw material gas. Needless to say, the final residual gas may be used as a by-product.

  In order to solve the above-mentioned problems, the present inventors have conducted intensive research and found that the above-described object can be achieved by the following gas component and condensable component manufacturing method and manufacturing apparatus, thereby completing the present invention. It reached. For elements having the same function, the upstream side is referred to as first or primary, and the downstream side is referred to as second or secondary.

The present invention uses a gas separation liquid function based on a separation function of a gas separation membrane having selective permeability and a gas-liquid separation function based on a difference in condensability of each component for a raw material gas containing a plurality of components, Easily permeable and non-condensable component A-rich permeate gas obtained by the separation function, and at least two gas-liquid separation functions located upstream and downstream of the gas separation membrane. A by-product liquid rich in the component B and a by-product gas in which the component B is reduced, wherein at least the second step obtained by the gas-liquid separation function on the downstream side of the following step (1) Step of branching part of raw gas as circulating gas (2) Step of adjusting flow rate and increasing pressure of circulating gas (3) Primary cooling processing and primary gas-liquid separation processing of the circulating gas, or primary air Only liquid separation processing Step (4) Step of extracting the first by-product gas in which the component B obtained by the primary gas-liquid separation process is reduced (5) Mainly comprising the component B obtained by the primary gas-liquid separation process A step of extracting the first byproduct liquid (6) A step of heating the first byproduct gas and then supplying it to the gas separation membrane (7) A step of supplying the raw material gas before the pressurizing process and before the primary cooling process Step of mixing with the circulating gas either before the primary gas-liquid separation treatment, after the primary gas-liquid separation treatment or after the heat treatment (8) The primary pressure of the gas separation membrane or a process value linked thereto (9) A step of separating any of permeated gas and residual gas in the gas separation membrane (10) A step of extracting the permeated gas rich in component A as a product from the gas separation membrane (11) For the gas separation membrane Step (12) of extracting residual gas rich in component B (12) Step of performing secondary cooling treatment and secondary gas-liquid separation treatment of the residual gas (13) Component B obtained by the secondary gas-liquid separation treatment A step of extracting the reduced second byproduct gas (14), characterized in that it comprises a step of extracting a second byproduct liquid mainly composed of the component B obtained by the secondary gas-liquid separation process.

The present invention also includes a gas separation membrane having selective permeability for a source gas containing a plurality of components and at least two gas-liquid separation units based on the difference in condensability of each component, A permeate gas rich in easily permeable and non-condensable component A obtained from the separation membrane, a by-product liquid rich in hardly permeable and condensable component B obtained from the gas-liquid separator, and the component B An apparatus for generating a reduced by-product gas, at least the following component (a) a circulating gas flow path (b) formed by branching a by-product gas flow path from the downstream gas-liquid separation section A flow rate adjusting unit and a pressure increasing unit provided in the circulating gas channel; (c) a first supply gas channel connected to the circulating gas channel; and (d) a first cooling unit provided in the first supply gas channel. And a first gas-liquid separation part (e) by-product gas from the gas phase part of the first gas-liquid separation part A first by-product gas channel to be discharged (f) a first by-product liquid channel from which a by-product liquid is taken out from the liquid phase part of the first gas-liquid separation unit; and (g) the first by-product gas channel. The provided heating unit (h) the circulating gas flow path or the upstream of the boosting unit, the first cooling unit upstream, the first gas-liquid separation unit upstream, the first gas-liquid separation unit downstream, or the heating unit downstream A source gas channel that is joined to the first supply gas channel and is supplied with a source gas containing a plurality of components (j) A gas that is connected to the first by-product gas channel and separates into a permeate gas and a residual gas Separation membrane (k) Permeate gas channel from which permeated gas permeated from the gas separation membrane is taken out (m) Residual gas channel from which residual gas from the gas separation membrane is supplied (n) In the residual gas channel A second cooling section and a second gas-liquid separation section (p) arranged from the gas phase section of the second gas-liquid separation section; A second by-product gas flow path (q) through which gas is supplied (q) a second by-product liquid flow path from which a by-product liquid is taken out from the liquid phase part of the second gas-liquid separation part (r) It has the 2nd pressure adjustment part arrange | positioned by the byproduct gas flow path.

  An easily permeable and non-condensable component (referred to as “component A” in the present invention) and a hardly permeable and condensable component (referred to as “component B” in the present invention) from a source gas containing a plurality of components. As a method of ensuring the desired product gas and condensable components with the desired purity and recovery rate, a method using a separation function by a gas separation membrane having selective permeability and the condensability of each component There is a method using a gas-liquid separation function based on the difference, and it has been often used separately. Also, when combining these, after using the latter as a pretreatment, a method of treating the treated gas with the former, or vice versa, may be used. And the other was the auxiliary. The present invention utilizes the fact that component B is concentrated in the residual gas of the gas separation membrane when the component gas is contained in the source gas, and a combination of a cooling unit and a gas-liquid separation unit is disposed before and after the gas separation membrane. In addition to preventing condensation of the components in the gas on the primary side of the gas separation membrane, the recovery rate of the permeated gas and the condensable component is improved.

  That is, by collecting component B at the first stage, the amount of component B moving to the residual gas is reduced to prevent condensation in the gas on the primary side of the gas separation membrane, and the efficiency of the permeated gas in the gas separation membrane Can be raised. In addition, by collecting the concentrated component B in the residual gas by the subsequent cooling unit and the gas-liquid separation unit, it is possible to ensure an unprecedented high recovery rate for the component B together with the recovery at the first stage. It becomes possible. In addition, when the temperature of source gas is comparatively low, it is possible to introduce directly into a gas-liquid separation part, without requiring the first stage cooling part.

  At this time, when the component gas is contained in the source gas, the component B is concentrated in the gas on the primary side of the gas separation membrane. Therefore, in order to prevent the generation of mist, the component A that should be originally extracted as the permeated gas is selected. It is necessary to leave a certain level in the residual gas and extract it as a residual gas with a lowered dew point. Therefore, in the actual operation, the component A is extracted as a result of being contained in the byproduct gas. Therefore, when this part is branched and mixed with the raw material gas as a circulating gas, the component A can be recovered and reused according to the flow rate. In particular, when the raw material gas contains a hardly permeable and non-condensable component, the concentration of the component in the residual gas increases due to the formation of the circulation system, so that the level of the component A can be lowered. The effect of. Therefore, while ensuring the desired product gas and condensable components with the desired purity, it is condensed in the gas on the primary side of the gas separation membrane, even for high recovery rates, using an efficient and versatile technique. It becomes possible to provide a manufacturing method and a manufacturing apparatus of a gas component and a condensable component that can avoid the liquefaction of the sexual component.

  Here, the “gas separation membrane” is not only a case where a single membrane module is used and each inflow / outflow passage for the supply gas, permeate gas and residual gas is provided, but a plurality of membrane modules are arranged in parallel. In addition, the case where the supply gas, the permeation gas, and the residual gas are integrated for each inflow / outflow path is included. The “condensable component” refers to a component having condensability with respect to the condensation treatment, and is not limited to difficulty in permeability to the gas separation membrane. “Easily permeable and non-condensable component” means a component that is easily permeable to the gas separation membrane and non-condensable to the condensation treatment. In the examples, for example, hydrogen in a case where hydrogen, methane, butane, and pentane are mixed in the raw material gas. “Non-condensable and non-condensable component” refers to a component that is hardly permeable to the gas separation membrane and non-condensable to the condensation treatment, and refers to methane in the above example. The term “refractory and condensable component” refers to a component that is hardly permeable to the gas separation membrane and condensable to the condensation treatment, and refers to butane and pentane in the above example. In addition, the present invention has essentially the same effect even when a small amount of a permeable and condensable component (for example, moisture in the raw material gas in Examples described later) is contained in the raw material gas. Therefore, it should be noted that the present invention includes such a case. In addition, the “process value linked with pressure” here refers to a process value that changes with a change in pressure, and includes a residual gas flow rate with respect to the primary pressure and a permeate gas flow rate with respect to the secondary pressure. The same applies hereinafter.

  The present invention is a method for producing the gas component and the condensable component, wherein the flow rate of the circulating gas is adjusted according to the degree of weight reduction during the weight reduction operation.

  When the raw material gas contains a hardly permeable and condensable component, in order to prevent liquefaction of the condensable component in the gas on the primary side of the gas separation membrane, the state where the dew point of the residual gas is kept low may be maintained. As described above, by forming a circulation system in which a part of the by-product gas is branched and mixed with the source gas as a circulation gas, the condensable component is liquefied in the gas on the primary side of the gas separation membrane. It can be avoided. However, when the raw material gas is reduced, if the primary pressure of the gas separation membrane is kept constant, the concentration of the permeable gas at the outlet of the residual gas is lowered, and the condensable component is easily liquefied. . At this time, if the flow rate of the circulating gas is increased, the concentration of the non-condensable component in the residual gas increases, so that the condensable component can be prevented from being liquefied. In this way, by adjusting the flow rate of the circulating gas according to the degree of weight loss, the desired product gas and condensable components having the desired purity and recovery rate can be secured, and the gas can also be used for a high recovery rate. It is possible to avoid liquefaction of the condensable component in the gas on the primary side of the separation membrane. In particular, when a booster is required for the raw material gas, it can also be used as a booster for circulating gas, and it is possible to utilize the surplus capacity of the booster in the reduction operation.

  The present invention provides a method for producing the gas component and the condensable component, wherein the primary pressure, the secondary pressure, or a process value associated therewith in the first gas separation membrane is reduced to a reduction degree during the reduction operation. It adjusts according to it, It is characterized by the above-mentioned.

  When the operation of reducing the source gas occurs, in addition to the effect of circulating a part of the second by-product gas, if the primary pressure P1 is reduced in accordance with the decrease in the flow rate of the source gas, the partial pressure of the condensable gas is lowered. Therefore, liquefaction of the condensable component in the gas on the primary side of the first gas separation membrane can be prevented. The same effect can be obtained by adjusting the residual gas flow rate in place of the primary pressure P1. Furthermore, by adjusting the secondary pressure P2 or adjusting the amount of permeate gas to reduce the increase in the permeate gas recovery rate, condensation in the gas on the primary side of the first gas separation membrane can also be achieved. The liquefaction of the sex component can be prevented.

The present invention is a method for producing the gas component and the condensable component, wherein the flow rate ratio between the flow rate of the circulating gas and the flow rate of the raw material gas is set as r,
Based on the raw material gas composition and the characteristics of the gas separation membrane, a reference value Za for the dew point Z under pressure immediately after the residual gas flow path outlet of the gas separation membrane is set, and the pressure and residual pressure of the residual gas in the gas separation membrane are set. The correlation function between the concentrations of the component A in the gas is analyzed in advance in a form including the flow rate ratio r as a parameter,
In operation, the correlation function is used to monitor the dew point Z from the measured value of the flow rate ratio r and the concentration of the component A in the residual gas so that the dew point Z is not more than the reference value Za. If the value Za is exceeded, the flow rate of the circulating gas, the pressure of the residual gas of the gas separation membrane, the pressure of the permeating gas or the process value linked to these are adjusted, and kept below the reference value Za, Liquefaction in the gas on the primary side of the gas separation membrane is prevented.

  When the raw material gas composition supplied to the gas separation membrane and the residual gas dew point are fixed, 1 / Pr and X are linear between the residual gas pressure Pr and the concentration X of the component A in the residual gas. The correlation function can be expanded to include various parameters, and can be used to avoid liquefaction of condensable components on the primary side of the gas separation membrane in specific cases (special features). Application 2007-232918). The present invention is based on the dew point under pressure immediately after the outlet of the residual gas passage, and is expanded to include a flow rate ratio r between the circulating gas flow rate and the raw material gas flow rate, and also by numerical value analysis in the examples described later. The effectiveness was confirmed. This correlation function is used to determine whether to prevent liquefaction on the primary side of the gas separation membrane. If necessary, either the circulating gas flow rate, the residual gas pressure of the gas separation membrane, the permeate gas pressure, or a process value linked to these can be selected. Adjustments can be made. Hereinafter, the dew point under pressure immediately after the outlet of the residual gas flow path is referred to as “residual gas dew point Z”, and the reference values thereof are Za and Zb. Provided is a gas component and a method for producing a condensable component that can avoid the liquefaction of the condensable component in the gas on the primary side and obtain the highest possible recovery rate while ensuring the desired purity. It becomes possible.

  The present invention is a method for producing the above gas component and condensable component, which uses a plurality of stages of the gas separation membrane, and supplies the residual gas of the gas separation membrane of the preceding stage to the gas separation membrane of the subsequent stage to form a cascade connection It is characterized by doing.

  Further, the present invention provides the above-described apparatus for producing a gas component and a condensable component, wherein the gas separation membrane is used in a plurality of stages, and the residual gas flow path of the preceding gas separation membrane is used as the supply gas flow of the latter gas separation membrane. It is characterized by connecting to the road and forming a cascade connection.

  Usually, the cascade cycle uses a plurality of stages of gas separation membranes when producing a plurality of product gases having different purities, and each permeate gas is a product gas. Product purity and recovery rate can be ensured. In addition to the general advantage of this cascade cycle, according to the present invention that circulates a part of the second by-product gas, while avoiding liquefaction of condensable components in the gas on the primary side of the gas separation membrane, A higher recovery rate is secured. In addition, since the residual gas from the gas separation membrane in the previous stage contains a relatively large amount of permeated gas, the residual gas dew point is relatively low and the possibility that the condensable component is liquefied is low. By successively controlling the primary pressure of the membrane, it is possible to avoid liquefaction even if the condensable component is concentrated as it is sequentially supplied to the subsequent gas separation membrane. The recovery rate can be increased. Therefore, while ensuring the desired product gas and condensable components with the desired purity and recovery rate, the gas on the primary side of the gas separation membrane can also be used for high recovery rates with an efficient and versatile technique. It is possible to provide a method for producing a gas component and a condensable component and a production apparatus that can avoid liquefaction of the condensable component therein.

  As described above, by applying the method and apparatus for producing a gas component and a condensable component according to the present invention, the desired product gas and the condensable component having a desired purity and recovery rate are ensured and efficiency is improved. Gas component capable of avoiding liquefaction of condensable components in the gas on the primary side of the gas separation membrane and a method for producing the condensable components, and a high recovery rate by a general and general technique, and A manufacturing apparatus can be provided. In particular, a higher recovery rate can be obtained during the weight reduction operation.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Here, for a source gas containing a plurality of components, a separation function using a gas separation membrane having selective permeability and a gas-liquid separation function based on the difference in condensability of each component are used to obtain the separation gas. A permeation gas rich in easily permeable and non-condensable component A and a low-permeability and condensable component B-rich side gas obtained by at least two gas-liquid separation functions located upstream and downstream of the gas separation membrane. In the process of generating a by-product gas in which the raw liquid and component B are reduced, the raw material gas is subjected to primary cooling treatment and primary gas-liquid separation treatment and residual gas secondary treatment before and after the selective separation treatment by the gas separation membrane. A cooling process and a secondary gas-liquid separation process are performed, and a part of the second by-product gas is branched and circulated to join the raw material gas, so that a permeated gas having a desired purity is produced and a condensable component is also desired. Times It is the basic to ensure the rate. The conditions required for this process vary depending on the upstream and downstream process configurations and product gas applications, and the operating conditions and control method are selected accordingly. Mentioned. The present invention is not limited to the configuration examples described below, and many variations and expansions are possible by combining the above characteristics in general with gas separation membrane processes.

<Example of basic configuration of gas component and condensable component manufacturing apparatus according to the present invention>
FIG. 1 shows a configuration example (first configuration example, the present apparatus 1) of a gas component and condensable component production apparatus (hereinafter referred to as “the present apparatus”) according to the present invention. Specifically, the raw material gas flow path Uo, the first supply gas flow path U1, the first by-product gas flow path G1, the first by-product liquid flow path L1, the gas separation membrane S, the permeate gas flow path T1, the residual gas. The first cooling section C1 and the first gas-liquid separation provided in the flow path R1, the second by-product gas flow path G2, the second by-product liquid flow path L2, the circulation gas flow path Fa, the first supply gas flow path U1. Part D1, heating unit H provided in the first by-product gas flow path G1, first liquid level detection unit LC1 and first control valve LCV1 provided in the first by-product liquid flow path L1, residual gas flow path R1 Pressure adjusting means PCr1 (pressure control valve PCV1 and pressure regulator PC1) provided in the second cooling part C2 and the second gas-liquid separation part D2 provided in the second by-product gas flow path G2, and the second by-product. The second liquid level detector LC2 and the second control valve LCV2 provided in the liquid flow path L2, and the flow provided in the circulation gas flow path Fa It consists adjusting means FCR1 (flow control valve FCV1 and flow adjusting meter FC1) and the step-up unit E, and a control unit (not shown). Here, the circulation gas flow channel Fa starts from a branch point provided in the second by-product gas flow channel G2, and flows through the first supply gas flow channel U1 (raw material gas flow through the flow rate adjusting means FCr1 and the booster E. Connected to the path Uo). Also, a raw material gas analysis port APo and a permeate gas analysis port AP1 (used for batch analysis by a gas chromatograph, etc.) are provided for performance confirmation of the gas production process. It should be noted that a concentration measuring means can be provided instead of the analysis port. Details will be described later.

  In the present apparatus 1, when the source gas contains a relatively large amount of component B, the source gas is subjected to primary cooling processing and primary gas-liquid separation processing, and selective separation processing using a gas separation membrane, which is performed to prevent mist generation. In order to reduce the load of the secondary gas cooling process and the secondary gas-liquid separation process of the residual gas, a part of the second by-product gas with less condensable components after the secondary gas-liquid separation process is branched and circulated. When mixed with the source gas as a gas, the component A (for example, hydrogen) can be recovered and reused according to the flow rate. In other words, the formation of such a circulation system increases the hydrogen concentration in the first supply gas, so there is no need to artificially increase the hydrogen concentration remaining in the residual gas, and the conditions set according to the characteristics of the gas separation membrane S can be set. The effect of being able to do is also added.

  At this time, the mixing point of the source gas and the circulating gas is not limited to the point immediately before the pressurizing unit E as shown in FIG. 1, but as indicated by broken lines a to d depending on the pressure, temperature, or dew point of the source gas. A: intermediate between the booster E and the first cooling part C1, b: intermediate between the first cooling part C1 and the first gas-liquid separation part D1, c: between the first gas-liquid separation part D1 and the heating part H or d : It can be provided between the heating part H and the gas separation membrane S. Such a configuration can be similarly applied to the following configuration examples. In the case of a, when the booster E is used only for boosting the circulating gas, it is only necessary to compensate for the pressure loss of the circulating loop, and the ejector is used to suck the circulating gas by the flow of the source gas. Then, it is possible to use this method.

  In the present apparatus 1, the configuration in which the primary pressure P1 for supplying the raw material gas is controlled by the pressure adjusting means PCr1 provided in the second by-product gas flow path G2, but the pressure adjusting means PCr1 is controlled. The material gas flow path Uo, the supply gas flow path U1, the first by-product gas flow path G1, the first residual gas flow path R1, or a configuration in which a separate bypass flow path is additionally provided, and the like are limited thereto. It goes without saying that it is not a thing. In addition, since the condensation in the second gas-liquid separation part D2 is generally more effective in a high pressure state, the pressure control valve PCV1 may be placed after the circulation gas branch point of the second by-product gas flow path G2. desirable. Further, instead of controlling the primary pressure P1, it is also possible to control the residual gas flow rate as a process value that changes as the primary pressure changes. The same applies hereinafter.

The raw material gas is preferably a refined gas or a refined gas supplied from a refined gas, specifically, purified air, purified naphtha cracked gas, purified reformed gas, purified water gas, purified natural gas, etc. To do. The supply conditions of the source gas are usually the ambient temperature, and the various gases described above having a flow rate of about 1,000 to 100,000 [Nm ³ / h] are used. In addition, the pressure condition varies depending on the use of the permeating gas, but is pressurized to about 1 to 50 [bar (abs)].

  For the gas separation membrane S, an optimum material, capacity (surface area), shape, or the like is selected depending on the type of the source gas or the permeated gas. Examples of the material of the gas separation membrane S include separation membranes such as polyethylene (PE), polypropylene (PP), silicone rubber, polysulfone, cellulose acetate, polyaramid (PA), and polyimide (PI). The apparatus 1 is not limited to these.

  Here, it is preferable to provide a heating means (heating unit H) in the first by-product gas flow path G1 for supplying the source gas to the gas separation membrane S. The gas separation membrane S desirably performs gas separation at an appropriate temperature according to its characteristics and application, and it is necessary to heat the source gas to an appropriate temperature. Further, when liquid mist is contained in the raw material gas, depending on the material of the gas separation membrane S, the alteration may occur. More specifically, when a high-boiling component is contained in the raw material gas, liquefaction may occur at room temperature. When this high-boiling component is a hardly permeable gas, the primary side of the gas separation membrane S is used. There is a risk that high-boiling components concentrate in the gas and liquefy. Therefore, after the source gas is cooled to, for example, about 40 ° C. (summer conditions) by the first cooling part C1 provided in the first supply gas flow path U1, and the condensed liquefied component is separated by the first gas-liquid separation part D1, By heating in the heating part H, the possibility of generating liquid mist in the gas separation membrane S can be avoided. However, when the high-boiling component contained in the raw material gas is small, it is possible to pass through the first cooling section C1 (that is, supply of the raw material gas to the first supply gas flow path U1), and further Can pass through the first gas-liquid separation part D1 (that is, supply of the raw material gas to the first by-product gas flow path G1).

  The gas collected from the analysis ports APo and AP1 can be batch-analyzed using gas chromatography or the like, and a method of correcting the coefficient of the arithmetic expression from the periodic analysis results can be adopted. Alternatively, the density measuring means can be used for control as will be described later. The concentration measuring means is preferably an analyzer having high selectivity with respect to a desired component, that is, a product gas component, and preferably a device that can be trusted by continuous analysis. An analyzer that does not cause a chemical change in the product gas is preferable. For example, when the component is hydrogen, a thermal conductivity analyzer can be used, and when the component is methane, an infrared absorption analyzer can be used. In addition, a method using both batch analysis and continuous analysis is also possible. While checking the error of the continuous analyzer from the result of more reliable batch analysis, it can be used for judgment of fine adjustment.

[Example of control method using the apparatus 1]
In the process from the raw material gas supplied to the gas separation membrane S of the present apparatus 1 to the production of the final product gas and the condensable component, when the permeate gas of the gas separation membrane S is the product gas, the process gas is constituted by at least the following steps. Is done.
(1) A step of branching a part of the second by-product gas as a circulating gas (2) A step of adjusting the flow rate and increasing the pressure of the circulating gas: The flow rate at this time is a control target.
(3) A step of performing only the primary cooling process and the primary gas-liquid separation process of the circulating gas, or the primary gas-liquid separation process (4) the step of extracting the first byproduct gas (5) the step of extracting the first byproduct liquid Step (6) Step of supplying the gas separation membrane S after heat treatment of the first by-product gas (7) Step of supplying the raw material gas and mixing it with the circulating gas before the pressure increasing treatment: The point of mixing is the raw material gas Depending on the nature, it can be performed before the primary cooling process, before the primary gas-liquid separation process, after the primary gas-liquid separation process, or after the heat treatment.
(8) Step of adjusting either the primary pressure of the gas separation membrane S or the process value linked with this: The pressure at this time becomes the control target.
(9) Step of separating permeate gas and residual gas in gas separation membrane S (10) Step of extracting permeate gas as product (11) Step of extracting residual gas (12) Secondary cooling treatment and secondary air of residual gas Step of performing liquid separation process (13) Step of extracting second by-product gas (14) Step of extracting second by-product liquid

  Here, in order to adjust the product gas concentration and the recovery rate to desired ranges, it is preferable to control the primary pressure P1 and simultaneously control the flow rate F1 of the circulating gas. Specifically, based on the concentration of the desired component collected from the analysis ports APo and AP1, pressure adjusting means PCr1 (pressure control valve PCV1 and pressure regulator PC1) provided in the second by-product gas flow path G2, The flow rate is controlled by flow rate adjusting means FCr1 (flow rate control valve FCV1 and flow rate controller FC1) provided in the circulation gas flow path Fa.

  In the reduction operation, (i) a method of adjusting the primary pressure P1 or the secondary pressure P2 of the gas separation membrane S according to the amount of reduction, and (ii) the circulation gas flow rate F1 according to the amount of reduction. It is possible to use a method of adjusting, and (iii) a method of adjusting by combining (i) and (ii) according to the degree of weight loss.

(I) Method for adjusting the primary pressure P1 or the secondary pressure P2 of the gas separation membrane S according to the degree of weight reduction When the raw material gas contains a hardly permeable and condensable component, If the primary pressure P1 of the separation membrane S is kept constant, the condensable component may be liquefied in the gas on the primary side of the gas separation membrane S as described above. In addition to the effect of circulating a part of the second by-product gas, when the primary pressure P1 is lowered in accordance with the decrease in the flow rate of the raw material gas, the partial pressure of the condensable gas is lowered. Liquefaction of the condensable component in the primary gas can be prevented. At this time, since the flow rates of the permeate gas and the residual gas also change according to the flow rate of the raw material gas, a stable recovery rate in the weight reduction operation can be ensured.

  However, depending on the required specifications for the product, there may be no problem in reducing the concentration of the permeable gas or causing the liquefaction of the condensable component in the gas on the primary side of the gas separation membrane S when reducing the amount. It may be preferable to keep the value constant. Further, depending on the required specifications for the product, a method of calculating the set value by a function (for example, a linear expression) of the flow rate of the raw material gas to the gas separation membrane S or the flow rate of the permeate gas may be preferable. Further, the calculation is performed by the line-segment function of the weight loss rate. For example, the primary pressure P1 is decreased according to the weight loss rate in the subsequent weight loss rate without decreasing the primary pressure P1 until the predetermined weight loss rate. May be preferred. In other words, by applying the configuration or method as described above, the purity of the desired product gas and the stability of the recovery rate can be ensured with a simple method without changing the number of modules even when the flow rate of the raw material gas decreases. It became possible to do. Note that the recovery rate increases when the primary pressure P1 and the secondary pressure P2 are kept constant during the reduction, but a method of increasing the secondary pressure P2 to suppress the increase in the recovery rate and preventing liquefaction is also possible. . Alternatively, when the secondary pressure P2 can be lowered, a method of simultaneously reducing the primary pressure P1 and the secondary pressure P2 is also possible.

(Ii) Method of adjusting the flow rate F1 of the circulating gas according to the degree of reduction The circulating gas is composed of a gas in which the component B is reduced because a part of the second by-product gas is branched. Therefore, by controlling the flow rate of the circulation gas corresponding to the reduction amount to be additionally mixed with the raw material gas without reducing the primary pressure P1, the influence of the reduction operation is reduced, and the gas separation membrane The risk of liquefaction of the condensable component in the primary gas can be reduced, and the product gas and the condensable component can be produced while ensuring stable product purity and recovery.

(Iii) Method of adjusting by combining (i) and (ii) according to the degree of weight loss In the weight reduction operation, an operation aimed at maintaining the product gas flow rate or an operation aimed at maintaining the recovery rate of a desired component While the operation contents differ depending on the required specifications, the characteristics and the risk of condensation change depending on the weight loss rate. Therefore, as described above, in the method (i) and the method (ii), it is possible to reduce the influence of the weight loss operation by using the different technical effects and adjusting them in combination. Product gas and condensable components can be produced while ensuring stable product purity and recovery. Specifically, until the predetermined reduction rate, the primary pressure P1 is not reduced, and the flow rate F1 of the circulation gas corresponding to the reduction is controlled to be additionally mixed with the raw material gas, and the reduction rate beyond that is controlled. In this case, by reducing the primary pressure P1 in accordance with the weight loss rate, it is possible to avoid the risk of condensation while ensuring stable product purity and recovery rate.

  Further, as described above, the flow rate ratio between the circulating gas flow rate and the raw material gas flow rate is set to r, and the reference value Za of the residual gas dew point Z is set based on the raw material gas composition and the characteristics of the gas separation membrane, and the gas separation membrane. The correlation function between the residual gas pressure and the concentration of the component A in the residual gas is analyzed in advance in a form including the flow rate ratio r as a parameter. It is also effective to perform the above controls (i) and (ii) so that the residual gas dew point Z is not more than the reference value Za from the measured value of the concentration of the component A in the residual gas. The same applies to other configuration examples thereafter.

[Variation 1 of the apparatus 1]
Modification 1 of the device 1 is shown in FIG. Although the basic configuration is the same as that of the first configuration example, an apparatus is further provided in which pressure adjusting means PCro (pressure control valve PCVo and pressure regulator PCo) is provided in the first by-product gas flow path G1. In the operation of reducing the source gas, the primary pressure Po of the first gas-liquid separation part D1 can be independently controlled with respect to the primary pressure P1 of the gas separation membrane S, and the pressure is controlled to be higher. It becomes possible to do. Note that the mixing point of the source gas and the circulating gas is as follows: a: intermediate between the pressure increasing unit E and the first cooling unit C1, b: the first cooling unit C1 and the first gas-liquid separation unit In the middle of D1, c: can be provided in the middle of the first gas-liquid separator D1 and the pressure adjusting means PCro.

[Modification 2 of the apparatus 1]
A modification 2 of the apparatus 1 is shown in FIG. The basic configuration is the same as in the first configuration example, but a branch point is provided in the second by-product gas flow path G2, and the permeate gas flow through the flow rate adjusting means FCr3 (the flow rate control valve FCV3 and the flow rate controller FC3). An apparatus in which the additive gas flow path Fc connected to the path T1 is formed is configured. An analysis port AP3 for performance confirmation is provided in the product gas flow path A1 from which the product gas obtained by mixing the permeated gas and the additive gas is taken out. By adding the easily permeable and non-condensable components concentrated in the second by-product gas by gas-liquid separation of the residual gas to the permeated gas, the recovery rate of the permeated gas and the condensable component is improved. It is. In addition, by limiting the dew point of the residual gas, liquefaction on the primary side of the gas separation membrane S is avoided, and the by-product gas by-produced in the second gas-liquid separation unit D2 is effectively used as the additional gas. By using it, it becomes possible to ensure a high recovery rate.

  Specifically, the primary pressure P1 is controlled by the pressure adjusting means PCr1 provided in the by-product gas flow path G2 of the gas separation membrane S based on the concentration of the desired component collected from the analysis ports APo and AP1. The flow rate F1 of the circulating gas is controlled by the flow rate adjusting means FCb1. Next, the flow rate F3 of the additive gas is controlled by the flow rate adjusting means FCb3. At this time, it is also possible to control the flow rate F3 of the additive gas based on the concentration of the desired component collected from the analysis port AP3. Further, in the weight reduction operation, the primary pressure P1 and the circulation gas flow rate F1 are controlled to be additionally mixed with the raw material gas in accordance with the degree of weight reduction, and then the additive gas flow rate F3 is controlled. The product gas and the condensable component can be produced while ensuring the stable product purity and recovery rate. In this configuration example, a part of the by-product gas obtained in the gas-liquid separation process is added to the secondary flow path of the gas separation membrane to increase the permeate recovery rate of the gas separation membrane (Japanese Patent Application No. 2007-233029), but the combination with other configuration examples of the above patent is also effective.

<The 2nd structural example of the manufacturing apparatus of the gas component which concerns on this invention, and a condensable component>
The 2nd structural example of the manufacturing apparatus of the gas component which concerns on this invention, and a condensable component is shown in FIG. The basic configuration is the same as in the first configuration example, but using a plurality of gas separation membranes, connecting the residual gas flow path of the preceding gas separation membrane to the supply gas flow path of the subsequent gas separation membrane, A device forming a cascade connection (hereinafter referred to as “the present device 2”) is configured. That is, by connecting the first residual gas passage R1 of the first gas separation membrane S1 to the supply gas passage of the second gas separation membrane S2, the first permeation gas is taken out from the first permeation gas passage T1, It becomes possible to take out the second permeable gas from the second permeable gas flow path T2.

  The cascade cycle is often used from the advantage that the recovery rate can be increased when the permeate gas having a plurality of purity conditions is obtained by changing the permeate gas pressure of each stage, the material of the gas separation membrane, and the like. Here, since the residual gas from the gas separation membrane in the previous stage contains a relatively large amount of non-condensable gas, the dew point of the residual gas is relatively low, and the possibility that the condensable component is liquefied is low. The condensable components are concentrated and can be efficiently recovered as they are sequentially supplied to the subsequent gas separation membrane. At this time, by selecting the membrane areas of the first gas separation membrane S1 and the second gas separation membrane S2, the concentration of the condensable component in the second residual gas can be adjusted to efficiently prevent liquefaction. Is possible.

  By having a circulation system in addition to the function based on the cascade cycle, the concentration of the non-condensable component in the first supply gas is increased, and the condensability in the gas on the primary side of the first and second gas separation membranes is increased. It is possible to prevent liquefaction of components and flexibly cope with changes in processing conditions during the weight reduction operation.

[Modification of the device 2]
A modification of the apparatus 2 is shown in FIGS. That is, the basic configuration is the same as that of the second configuration example, but in FIG. 5, an apparatus in which the pressure adjusting means PCr2 (pressure control valve PCV2 and pressure regulator PC2) is provided in the first residual gas flow path R1. Is configured. Also in reduction operation of the feed gas, it is possible to control the primary pressure P1 ₁ pressure and the first gas separation membrane S1 of the first gas-liquid separator D1 in the primary pressure P1 ₂ independent of the second gas separation membrane S2 It becomes possible. In FIG. 6, pressure adjusting means PCr2 (pressure control valve PCV2 and pressure regulator PC2) is provided in the first residual gas flow path R1, and pressure adjusting means PCro (in addition to the first by-product gas flow path G1). A device provided with a pressure control valve PCVo and a pressure regulator PCo) is constructed. Even in the operation of reducing the source gas, the pressure of the first gas-liquid separation part D1 can be controlled independently of the primary pressure of the first and second gas separation membranes S1 and S2, and the pressure is controlled to be higher. This makes it possible to perform highly versatile control. In addition, as shown by broken lines a to c, the mixing point of the source gas and the circulating gas in FIG. 6 is a: intermediate between the pressure-increasing part E and the first cooling part C1, and b: the first cooling part C1 and the first air. It can be provided in the middle of the liquid separation part D1, c: in the middle of the first gas-liquid separation part D1 and the pressure adjusting means PCro.

[Another configuration example of the apparatus 2]
In the present apparatus 2, the case where two stages of gas separation membranes are provided and connected to the cascade has been described. However, by using a larger number of gas separation membranes, a highly versatile gas production apparatus that takes advantage of its function is used. Is also possible. For example, a part of the gas is divided into a plurality of groups connected in parallel as a first gas separation membrane so as to obtain product gas of different conditions, and the residual gases of each group are collected to form a second gas separation membrane. It is also possible to change to supply.

  Further, it is possible to apply a configuration or function as in the present invention by providing a third gas separation membrane in the second residual gas flow path R2 of the second gas separation membrane S2 at the subsequent stage. Furthermore, by sequentially arranging a plurality of such gas separation membranes in order of 4th and 5th, the purity of each product gas based on individual specifications and a high recovery rate as a whole according to the present invention are ensured. Is possible. In addition, it is possible to further increase the recovery rate of the permeable gas by sequentially controlling the primary pressure of the gas separation membrane in each stage.

  Furthermore, when two gas separation membranes S1 and S2 are provided, the product gas 1 from one first gas separation membrane S1 and the product gas 2 from the other second gas separation membrane S2 can be obtained separately. However, it is also possible to mix at least a part of these to produce one product gas, and further, by arranging a plurality of gas separation membranes continuously, each product based on various specifications It is possible to ensure the purity of the gas and ensure a high recovery rate as the entire apparatus 2.

<The 3rd example of composition of the manufacture device of the gas ingredient and the condensable ingredient concerning the present invention>
FIG. 7 shows a third configuration example (hereinafter referred to as “the present apparatus 3”) of the gas component and condensable component production apparatus according to the present invention. The basic configuration is the same as that of the first configuration example shown in FIG. 1, but the circulation gas flow path Fb and the flow rate adjusting means FCr2 (flow rate control valve FCV2 and flow rate controller FC2) provided in the circulation gas flow path Fb. ) Is added. Here, the circulation gas flow path Fb is connected to the circulation gas flow path Fa on the downstream side of the flow rate adjusting means FCr1 via the flow rate adjusting means FCr2 starting from the branch point provided in the first permeate gas flow path T1. The

  By having the circulating gas consisting of the first permeated gas in addition to the circulating gas consisting of a part of the second by-product gas, the concentration of the non-condensable component in the first supply gas containing the easily permeable component is increased, It is possible to easily prevent liquefaction of the condensable component in the gas on the primary side of the gas separation membrane and to prevent a decrease in the purity of the permeated gas during the weight reduction operation.

  Next, regarding the above configuration example, the results of setting the hydrogen gas production process and performing the numerical analysis of the purity and recovery rate of the permeated gas are shown below.

（１−２）解析に用いたガス分離膜は、第１および第２ガス分離膜ともに、素材をポリアラミド系膜とした。
（１−３）原料ガスのガス分離膜入口温度は、９０℃とした。
（１−４）残留ガス露点Ｚは８０℃以下を基準とする。
（１−５）第１，第２冷却部として水冷却方式を用い、４０℃まで冷却する。
（１−６）原料ガスの流量の最大値は、１０，０００Ｎｍ^３／ｈとし、以下「流量」は、この最大値に対する割合（％）によって表示した。
（１−７）透過ガスの圧力は、ガス分離膜出口において１５ｂａｒ（ａｂｓ）とした。
（１−８）本装置の圧力損失
（ｉ）原料ガスの流量が最大（１００％）のとき：第２冷却器、第２気液分離部の圧力損失は０．２ｂａｒと仮定した。
（ii）減量時の圧力損失：本装置の圧力損失は、上記１００％の場合を基準として、ρＶ^２に比例して変化するものと仮定して評価した。但し、ここにρ（ｋｇ／ｍ^３）はガスの密度、Ｖ（ｍ^３／ｈ）は体積流量を表す。
（１−９）本装置の圧力基準点
（ｉ）原料ガスの流量が最大のとき：第１気液分離部における第１副生ガスの圧力は、３８ｂａｒ（ａｂｓ）を基準とした。
（ii）減量操作時：制御方法に依存する。ここでは、ガス分離膜が１段のときは、残留ガス流路の圧力（第２気液分離部からの第２副生ガスの圧力で代表した）を基準とし、ガス分離膜を２段用いたカスケードサイクルの場合は、第１残留ガス流路の圧力（第１残留ガス流路の第１ガス分離膜直近の圧力で代表した）、または第２残留ガス流路の圧力（第２気液分離部からの第２副生ガスの圧力で代表した）を基準とした。但し、表５、表６においてＰｒと記したものおよび表７の括弧内は、第１残留ガス流路の第１ガス分離膜直近の圧力を示す。 (1) Analysis conditions (1-1) Table 1 shows the composition of the source gas.

(1-2) The gas separation membrane used for the analysis was a polyaramid membrane for both the first and second gas separation membranes.
(1-3) The gas separation membrane inlet temperature of the raw material gas was 90 ° C.
(1-4) Residual gas dew point Z is based on 80 ° C. or less.
(1-5) A water cooling system is used as the first and second cooling sections, and cooling is performed to 40 ° C.
(1-6) The maximum value of the flow rate of the raw material gas was set to 10,000 Nm ³ / h, and the “flow rate” was expressed as a ratio (%) to the maximum value.
(1-7) The pressure of the permeating gas was 15 bar (abs) at the gas separation membrane outlet.
(1-8) Pressure loss of this apparatus (i) When the flow rate of the raw material gas is maximum (100%): The pressure loss of the second cooler and the second gas-liquid separation unit was assumed to be 0.2 bar.
(Ii) Pressure loss at the time of weight reduction: The pressure loss of this apparatus was evaluated on the assumption that it changes in proportion to ρV ² on the basis of the case of 100%. Here, ρ (kg / m ³ ) represents the gas density, and V (m ³ / h) represents the volume flow rate.
(1-9) Pressure reference point of this apparatus (i) When the flow rate of the raw material gas is maximum: The pressure of the first by-product gas in the first gas-liquid separation unit is based on 38 bar (abs).
(Ii) During weight reduction operation: Depends on the control method. Here, when the gas separation membrane has one stage, the pressure of the residual gas flow path (represented by the pressure of the second by-product gas from the second gas-liquid separation unit) is used as a reference, and the gas separation membrane is used for two stages. In the case of the cascade cycle, the pressure of the first residual gas flow path (represented by the pressure immediately adjacent to the first gas separation membrane of the first residual gas flow path) or the pressure of the second residual gas flow path (second gas-liquid) (Represented by the pressure of the second by-product gas from the separation section). However, what is indicated as Pr in Tables 5 and 6 and the parentheses in Table 7 indicate pressures in the vicinity of the first gas separation membrane in the first residual gas flow path.

(2) Preliminary analysis (2-1) Study 1
With the apparatus of FIG. 1 (first configuration example), a certain membrane area was set, the raw material gas having the composition of Case 1 was flowed at the maximum flow rate, and the circulation gas flow rate was analyzed as zero. The recovery rate was 85.84%, and the hydrogen purity in the permeated gas was 99.7%. However, the residual gas dew point Z was about 91.3 ° C., which was a result of not satisfying the standard value of the dew point.

(2-2) Study 2
When increasing the flow rate of the circulating gas from the state of Study 1 above,
(I) The residual gas dew point Z decreases monotonously.
(Ii) The hydrogen purity of the permeate gas gradually falls.
(Iii) The recovery rate gradually increases after taking a maximum value of about 86.7% where it gradually increases.
(Iv) The permeate gas flow rate was changed in conjunction with the change in the recovery rate.

(2-3) Study 3
It was found that the residual gas dew point Z was 80 ° C. when the circulating gas flow rate was adjusted from the state of Study 2 above and the circulating gas flow rate was about 11.8%. The recovery rate at this time was 86.61%, and the hydrogen purity was 99.69%.
For comparison, the circulation gas flow rate is set to zero.
(I) When the primary pressure of the gas separation membrane was lowered with the same membrane area, the residual gas dew point Z reached 80 ° C. when the pressure of the first gas-liquid separator was about 34.8 bar (abs). . The recovery rate at this time decreased to 77.87%. The hydrogen purity was 99.73%.
(Ii) Further, when the film area was reduced (about 79% of the original area), the residual gas dew point Z was 80 ° C. The recovery rate at this time decreased to 77.45%. The hydrogen purity was 99.78%. From the above, the effectiveness of adjusting the residual gas dew point Z using circulating gas was proved.

(3) Analysis results (3-1) Example 1
With the apparatus of FIG. 1, the same membrane area as that in the preliminary analysis was set, and for the source gas having the composition of Case 1, the primary pressure of the gas separation membrane was kept constant, and the weight loss characteristics were examined. The circulating gas flow rate was adjusted so that the residual gas dew point Z was about 80 ° C.
The examination results are shown in Table 2.
It was found that the recovery rate increased markedly as the weight decreased. It can be seen that this approach can be used for applications where the hydrogen purity levels in Table 2 are acceptable.

(3-2) Example 2
In the modification of Example 1, the same membrane area as in the preliminary analysis and Example 1 is set, the hydrogen purity is 99.0% or more, and the residual gas pressure of the gas separation membrane is changed by a linear expression of the reduction degree. The case where weight reduction operation was performed was analyzed. The circulating gas flow rate was constant during the reduction operation.
The examination results are shown in Table 3.
It was found that even when this operation was performed, the recovery rate increased markedly as the weight decreased.

(3-3) Example 3
As a modification of the second embodiment, the same membrane area as that of the preliminary analysis and the first and second embodiments is set. As shown in FIG. 2 (corresponding to a modification of the first configuration example), the pressure of the first gas-liquid separation unit is changed. The amount reduction operation when the residual gas pressure of the gas separation membrane S was changed by the linear expression of the degree of reduction was kept constant. At the maximum flow rate, the differential pressure of the pressure holding valve (PCVo) of the first gas-liquid separation unit was assumed to be 0.2 bar. The circulating gas flow rate was constant during the reduction operation.
The examination results are shown in Table 4.
At the maximum rating, the recovery rate was slightly lower due to the pressure difference of the pressure retaining valve (PCVo), but it was found that the recovery rate increased compared to Example 2 when the amount was reduced.

(3-4) Example 4
As in the third embodiment, as shown in FIG. 2, the case where the pressure of the first gas-liquid separation unit is kept constant will be considered. However, the correlation function between the residual gas pressure and the concentration of hydrogen (component A) in the residual gas was analyzed in advance in a form including the flow rate ratio r as a parameter, and the case where it was used for the weight reduction operation was analyzed. Therefore, the correlation function was obtained as follows.

(I) When the flow rate ratio r = 0.11 and the degree of weight loss was 100%, 70%, and 40%, the residual gas pressure was adjusted and the conditions under which the residual gas dew point Z was 80 ° C. were determined. The results are shown in Table 5. In addition, the value of the residual gas pressure Pr in Table 5 and the subsequent Table 6 indicates the pressure value in the immediate vicinity of the residual gas flow path of the gas separation membrane.

(Ii) Similarly, for the cases where the flow rate ratio r = 0.18 and the degree of weight loss is 80%, 60%, and 40%, the residual gas pressure was adjusted to obtain the conditions for the residual gas dew point Z to be 80 ° C. The results are shown in Table 6.

(Iii) When the reciprocal 1 / Pr of the residual gas pressure and the hydrogen concentration X in the residual gas are plotted, as shown in FIG. 8, for each of r = 0.11 and r = 0.18, it is almost linear. Correlation was confirmed. As correlation functions at this time, the following equations 1 and 2 were obtained.
_{X = a r -b r / Pe} ··· ( Equation 1)
_{Pe = b r / (a r} -X) ··· ( Equation 2)
Here, Pe means the residual gas pressure corresponding to the concentration X of the component A expected from the correlation function. Moreover, a _r = [(0.18−r) * a ₁ + (r−0.11) * a ₂ ] /0.07
b _r = [(0.18−r) * b ₁ + (r−0.11) * b ₂ ] /0.07
a ₁ and b ₁ are coefficients when r = 0.11.
a ₂ and b ₂ mean coefficients when r = 0.18.

Based on the above preparation, the circulating gas flow rate is changed by the linear expression of the degree of reduction, and the residual gas pressure of the gas separation membrane is lowered according to the degree of reduction according to the correlation function shown in the above formulas 1 and 2. The weight loss operation was analyzed. The analysis results are shown in Table 7. The residual gas pressure indicated both the pressure of the second gas-liquid separation part and the pressure Pr immediately adjacent to the residual gas flow path (the latter is shown in parentheses). When the degree of weight loss was 100% and 40%, the flow rate ratio r was 0.11 and 0.18, respectively, so the residual gas dew point Z was 80 ° C. When the degree of weight loss was 70%, there was a slight error, but it was confirmed that the above correlation equation had sufficient accuracy for practical use. Further, the hydrogen concentration in the permeate gas was able to secure a high recovery rate while maintaining the condition of 99 mol%.

(3-5) Example 5
A similar study was performed on the raw material having the composition of Case2. Similar effects were obtained with circulating gas. However, in the method of keeping the primary pressure of the gas separation membrane constant, if the reduction operation is performed, the second by-product gas flow rate becomes the limit even if the circulation gas flow rate is increased, and the residual gas dew point Z is not limited even if the entire amount is circulated. Was found to be 80 ° C. or higher. Further, when the primary pressure of the gas separation membrane was lowered, the second by-product gas flow rate was increased, and the residual gas dew point Z could be adjusted.
Accordingly, as in the third embodiment, as shown in FIG. 2, the pressure reduction operation is performed when the pressure of the first gas-liquid separation unit is kept constant and the residual gas pressure of the gas separation membrane is changed by the primary expression of the weight reduction degree. Was analyzed. The flow rate of the circulating gas was also changed by the primary expression for the degree of weight loss. At the maximum flow rate, the differential pressure of the pressure holding valve (PCVo) of the first gas-liquid separation unit was assumed to be 0.2 bar.
The examination results are shown in Table 8.
It was found that the recovery rate increased markedly as the weight decreased.

(3-6) Example 6
The same analysis was performed for the cascade cycle (FIG. 5, corresponding to a modification of the apparatus 2). The membrane areas of the first gas separation membrane and the second gas separation membrane were set to 100% and 50%, respectively, of the membrane areas of the gas separation membrane used in the preliminary study and Examples 1 to 3. The permeated gas pressures of the first gas separation membrane and the second gas separation membrane were the same, and they were merged into a product gas. The pressure of the first gas-liquid separation unit is kept constant, the residual gas pressure of the first gas separation membrane and the second gas separation membrane is changed by the primary expression of the reduction degree, and the circulation gas flow rate is proportional to the reduction degree did. The residual gas dew point Z of the first gas separation membrane and the second gas separation membrane was both limited to 80 ° C. or less, and the hydrogen purity of the permeated gas was 99 mol% or more. At the maximum flow rate, the differential pressure of the pressure holding valve (PCVo) of the first gas-liquid separation unit was assumed to be 0.2 bar.
The examination results are shown in Table 9.
The recovery rate could be over 90% in all cases.

(3-7) Example 7
As in the apparatus shown in FIG. 7 (corresponding to the third configuration example), a case where a part of the permeated gas is supplied to the circulating gas in addition to a part of the second by-product gas was examined. For the source gas having the composition of Case 1, the area of the membrane is changed according to the cases of the examinations 1 to 3, and the set value of the circulating gas flow rate from the permeate gas is changed by the primary expression of the raw material gas flow rate. The circulating gas flow rate and residual gas pressure were constant. In a wide weight loss range of 100% to 40%, a residual gas dew point Z of 80 ° C. or less was secured, and a high recovery rate was obtained with a hydrogen purity of 99 mol% or more.
The examination results are shown in Table 10.
It has been found that by adding at least a part of the permeate gas to the circulating gas, the purity of the permeate gas can be increased in the weight reduction operation, and a higher recovery rate can be obtained compared to Examples 2 and 3.

(4) Summary As shown in the above results, in all of Examples 1 to 7, it was possible to stably maintain high stability and high recovery rate with respect to the purity of the permeated gas.

Explanatory drawing which shows the basic structural example (1st structural example) of the manufacturing apparatus which concerns on this invention Explanatory drawing which shows the modification 1 of the 1st structural example of the manufacturing apparatus which concerns on this invention. Explanatory drawing which shows the modification 2 of the 1st structural example of the manufacturing apparatus which concerns on this invention. Explanatory drawing which shows the 2nd structural example of the manufacturing apparatus which concerns on this invention. Explanatory drawing which shows the modification of the 2nd structural example of the manufacturing apparatus which concerns on this invention. Explanatory drawing which shows the modification of the 2nd structural example of the manufacturing apparatus which concerns on this invention. Explanatory drawing which shows the 3rd structural example of the manufacturing apparatus which concerns on this invention. Explanatory drawing which shows the analysis result in the manufacturing apparatus which concerns on this invention Explanatory drawing illustrating the basic configuration of a manufacturing apparatus according to the prior art Explanatory drawing which illustrates another 1 structure of the manufacturing apparatus which concerns on a prior art Explanatory drawing illustrating the other two configurations of the manufacturing apparatus according to the prior art

Explanation of symbols

APo, AP1, AP2, AP3 Analysis ports C1, C2 (First and second) Cooling parts D1, D2 (First, second) Gas-liquid separation part E Boosting part Fa, Fb Circulating gas flow paths FC1, FC2 Flow rate adjustment Total FCr1, FCr2 Flow rate adjusting means FCV1, FCV2 Flow control valves G1, G2 (first and second) by-product gas flow path H heating parts L1, L2 (first and second) by-product liquid flow paths LC1, LC2 ( (First and second) liquid level detectors LCV1 and LCV2 (first and second) control valve Pr Residual gas pressure PCo, PC1, PC2 Pressure regulator PCro, PCr1, PCr2 Pressure adjusting means PCVo, PCV1, PCV2 Pressure control valve R1, R2 (first, second) residual gas flow paths S, S1, S2 (first, second) gas separation membranes T1, T2 (first, second) permeate gas flow paths Uo raw material gas flow paths U1, U2 (first and second) supply gas S channel X Hydrogen concentration

Claims (7)

For the raw material gas containing a plurality of components, the separation function of the gas separation membrane having selective permeability and the gas-liquid separation function based on the difference in condensability of each component are utilized. Permeable gas rich in easily permeable and non-condensable component A obtained, and at least two gas-liquid separating functions located upstream and downstream of the gas separation membrane, hardly permeable and condensable component B A by-product liquid rich in component B and a by-product gas reduced in component B, wherein at least one of the second by-product gas obtained by the gas-liquid separation function on the downstream side of the following step (1) (2) Step of adjusting the flow rate and increasing the pressure of the circulating gas (3) Primary cooling processing and primary gas-liquid separation processing of the circulating gas, or only primary gas-liquid separation processing Process ( ) A step of extracting the first by-product gas in which the component B is reduced obtained by the primary gas-liquid separation process. (5) A first by-product mainly composed of the component B obtained by the primary gas-liquid separation process. (6) Step of supplying the gas to the gas separation membrane after heat-treating the first by-product gas (6) Supplying the raw material gas before the pressurizing process and before the primary cooling process Step (8) of mixing with the circulating gas either before the liquid separation treatment, after the primary gas-liquid separation treatment or after the heat treatment (8) Either the primary pressure of the gas separation membrane or a process value linked thereto (9) Step of adjusting (9) Step of separating permeated gas and residual gas in the gas separation membrane (10) Step of extracting permeated gas rich in component A from the gas separation membrane as a product (11) Gas separation membrane Component B A step of extracting a rich residual gas (12) A step of performing a secondary cooling process and a secondary gas-liquid separation process of the residual gas (13) A second reduced amount of the component B obtained by the secondary gas-liquid separation process Extracting by-product gas (14) A method for producing a gas component and a condensable component, comprising a step of extracting a second by-product liquid mainly composed of component B obtained by the secondary gas-liquid separation process. .   2. The method for producing a gas component and a condensable component according to claim 1, wherein the flow rate of the circulating gas is adjusted in accordance with the degree of weight reduction during the weight reduction operation.   3. The gas component and condensation according to claim 1 or 2, wherein, during the weight reduction operation, either the primary pressure or the secondary pressure of the gas separation membrane or a process value linked with these is adjusted according to the degree of weight reduction. The manufacturing method of a sex component. Let r be the flow rate ratio between the flow rate of the circulating gas and the flow rate of the source gas,
Based on the raw material gas composition and the characteristics of the gas separation membrane, a reference value Za for the dew point Z under pressure immediately after the residual gas flow path outlet of the gas separation membrane is set, and the pressure and residual pressure of the residual gas in the gas separation membrane are set. The correlation function between the concentrations of the component A in the gas is analyzed in advance in a form including the flow rate ratio r as a parameter,
In operation, the correlation function is used to monitor the dew point Z from the measured value of the flow rate ratio r and the concentration of the component A in the residual gas so that the dew point Z is not more than the reference value Za. If the value Za is exceeded, the flow rate of the circulating gas, the pressure of the residual gas of the gas separation membrane, the pressure of the permeating gas or the process value linked to these are adjusted, and kept below the reference value Za, The method for producing a gas component and a condensable component according to any one of claims 1 to 3, wherein liquefaction in the gas on the primary side of the gas separation membrane is prevented.   5. The gas according to claim 1, wherein the gas separation membrane is used in a plurality of stages, and residual gas in the preceding gas separation membrane is supplied to the subsequent gas separation membrane to form a cascade connection. Component and condensable component production method. For a source gas containing a plurality of components, the gas separation membrane having selective permeability and at least two gas-liquid separation sections based on the difference in condensability of each component are easily obtained from the gas separation membrane. Permeated gas rich in permeable and non-condensable component A, by-product liquid rich in hardly permeable and condensable component B obtained from the gas-liquid separator, and by-product gas reduced in component B An apparatus for generating a circulating gas flow path formed by branching at least the following component (a) by-product gas flow path from the downstream gas-liquid separation section; and (b) the circulating gas flow path A flow rate adjusting unit and a pressure increasing unit provided; (c) a first supply gas channel connected to the circulating gas channel; and (d) a first cooling unit and a first gas-liquid separation provided in the first supply gas channel. Part (e) A first by-product gas is taken out from the gas phase part of the first gas-liquid separation part. A raw gas flow path (f) a first by-product liquid flow path (g) from which a by-product liquid is taken out from a liquid phase part of the first gas-liquid separation part (g) a heating unit ( h) The circulating gas flow path or the first supply gas flow path in any one of the upstream of the boosting unit, the first cooling unit, the first gas-liquid separation unit, the first gas-liquid separation unit, or the heating unit. A gas separation membrane (k) connected to the first by-product gas flow path and separated into a permeate gas and a residual gas. A permeate gas channel from which a permeate gas permeated from the gas separation membrane is taken out (m) a residual gas channel from which the residual gas from the gas separation membrane is delivered (n) a second gas channel disposed in the residual gas channel Cooling section and second gas-liquid separation section (p) By-product gas from the gas phase section of the second gas-liquid separation section is delivered Second by-product gas channel (q) Second by-product liquid channel from which by-product liquid is taken out from the liquid phase part of the second gas-liquid separation unit (r) The second by-product gas channel after the branch A device for producing a gas component and a condensable component, comprising: a second pressure adjusting unit disposed in   7. The gas separation membrane is provided in a plurality of stages, and the residual gas flow path of the preceding gas separation membrane is connected to the supply gas flow path of the subsequent gas separation membrane to form a cascade connection. Equipment for producing gas components and condensable components.

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