Patent Description:
In the related art, a degasification unit that degasifies a liquid using hollow fiber membranes is known. Further, a degasification system in which a plurality of degasification units are housed in a housing to cope with an increase in size or flow rate is also known (see Patent Literature <NUM>, for example).

[Patent Literature <NUM>] <CIT>. Other degasification systems are disclosed in <CIT> and J<CIT>.

Incidentally, in a case in which a plurality of degasification units are housed in parallel in a housing, it was thought that a liquid flows through all the degasification units with the same flow rate. However, as a result of research by the present inventors, it has been found that a liquid may not always flow through all the degasification units with the same flow rate. That is, it has been found that the flow rates of the liquid flowing through the degasification units differ depending on the distance from the central axis of the housing. Since the degasification performance of a degasification unit changes depending on the flow rate of the liquid flowing through the degasification unit, it is assumed that the degasification performance of the entire degasification system deteriorates when the flow rates of the liquid flowing through each of the degasification units differ.

Therefore, an object of the aspect of the present invention is to provide a degasification system capable of reducing deviation in the flow rate of a liquid flowing through a plurality of degasification units, a liquid degasification method using the degasification system, and a method for manufacturing the degasification system.

A degasification system according to an aspect of the present invention includes a plurality of degasification units configured as defined in claim <NUM>.

In the degasification system, the plurality of degasification units are housed in parallel in the cylindrical housing. Here, in a case in which the pressure losses of the liquid flowing through the plurality of degasification units are the same, the flow rates of the liquid flowing through the degasification units differ depending on the distance from the central axis of the housing. However, in this degasification system, the plurality of degasification units are configured such that the pressure losses of the liquid differ depending on the distance from the central axis of the housing. This difference in the pressure loss acts to offset the above difference in the flow rate. As a result, it is possible to reduce the deviation in the flow rate of the liquid flowing through the plurality of degasification units. As a result, for example, the degasification performance of the degasification system in its entirety can be improved.

The degasification system includes a suction pipe communicating with an inside of the hollow fiber membranes and penetrating the housing to suction the inside of the hollow fiber membranes. In the degasification system, by providing the suction pipe, it is possible to appropriately degasify the liquid in the degasification unit, and it is possible to appropriately discharge the degasification gas to the outside of the housing.

Among the plurality of degasification units, the degasification unit that overlaps the inlet when seen in a direction along the central axis may be configured such that the pressure loss of the liquid therein is larger than that in the degasification unit that does not overlap the inlet when seen in a direction along the central axis. Since the degasification unit that overlaps the inlet when seen in a direction along the central axis receives a stronger supply pressure of the liquid from the inlet than that in the degasification unit that does not overlap the inlet when seen in a direction along the central axis, the liquid easily flows in the degasification unit that overlaps the inlet when seen in a direction along the central axis. In the degasification system, since the degasification unit that overlaps the inlet when seen in a direction along the central axis is configured such that the pressure loss of the liquid therein is larger than that in the degasification unit that does not overlap the inlet when seen in a direction along the central axis, this difference in the pressure loss acts to offset the difference in the supply pressure of the liquid. As a result, it is possible to reduce the deviation in the flow rate of the liquid flowing through these degasification units.

Incidentally, as described above, in a case in which the pressure losses of the liquid flowing through the plurality of degasification units are the same, the flow rate of the liquid flowing through the degasification unit tends to decrease as the degasification unit becomes further away from the central axis of the housing. However, as a result of research by the present inventors, it was found that the above tendency is reversed in an outer region from the inner peripheral surface of the housing to a position corresponding to <NUM> times the outer diameter of the degasification unit toward the central axis side. That is, it was found that in the outer region, the flow rate of the liquid flowing through the degasification unit tends to increase as the degasification unit becomes further away from the central axis of the housing. It is assumed that this is because, in the outer region, the liquid flowing in the housing is pushed back against the inner peripheral surface of the housing, and thus the flow rate of the liquid flowing through the degasification unit increases.

Based on this findings, in a case in which a region from an inner peripheral surface of the housing to a position corresponding to <NUM> times an outer diameter of the degasification unit toward the central axis side is defined as an outer region and a region inside the outer region is defined as an inner region, in the inner region, the plurality of degasification units may have an inner degasification unit and an outer degasification unit which is farther from the central axis than the inner degasification unit, and the inner degasification unit may be configured such that the pressure loss of the liquid therein is larger than that in the outer degasification unit. In a case in which the pressure losses of the liquid flowing through the plurality of degasification units are the same, in the inner region, the flow rate of the liquid flowing through the degasification unit tends to decrease as the degasification unit becomes further away from the central axis of the housing. In the degasification system, since the inner degasification unit is configured such that the pressure loss of the liquid therein is larger than that in the outer degasification unit, this difference in the pressure loss acts to offset the above difference in the flow rate. As a result, it is possible to reduce the deviation in the flow rate of the liquid flowing through the inner degasification unit and the outer degasification unit.

Further, in a case in which a region from an inner peripheral surface of the housing to a position corresponding to <NUM> times an outer diameter of the degasification unit toward the central axis side is defined as an outer region, a region inside the outer region is defined as an inner region, and all the degasification units are disposed in the inner region, the plurality of degasification units may be configured such that the pressure loss of the liquid increases as the degasification unit becomes closer to the central axis. In the degasification system, in a case in which all the degasification units are disposed in the inner region, the plurality of degasification units are configured such that the pressure loss of the liquid increases as the degasification unit becomes closer to the central axis, and thus it is possible to appropriately reduce the deviation in the flow rate of the liquid flowing through the plurality of degasification units.

On the other hand, in a case in which a region from an inner peripheral surface of the housing to a position corresponding to <NUM> times an outer diameter of the degasification unit toward the central axis side is defined as an outer region, a region inside the outer region is defined as an inner region, at least one degasification unit is disposed in the outer region, and remaining degasification units are disposed in the inner region, the degasification units disposed in the inner region may be configured such that the pressure loss of the liquid increases as the degasification unit becomes closer to the central axis. In the degasification system, in a case in which at least one degasification unit is disposed in the outer region and the remaining degasification units are disposed in the inner region, the degasification units disposed in the inner region are configured such that the pressure loss of the liquid increases as the degasification unit becomes closer to the central axis, and thus it is possible to appropriately reduce the deviation in the flow rate of the liquid flowing through the degasification units in the inner region.

In this case, the degasification unit disposed in the outer region may be configured such that the pressure loss of the liquid therein is larger than that in the degasification unit closest to the outer region among the degasification units disposed in the inner region. In the degasification system, since the degasification unit disposed in the outer region is configured such that the pressure loss of the liquid therein is larger than that in the degasification unit closest to the outer region among the degasification units disposed in the inner region, it is possible to appropriately reduce the deviation in the flow rate of the liquid even between this degasification unit disposed in the inner region and the degasification unit disposed in the outer region.

In the degasification unit, a plurality of degasification modules may be connected, each of the plurality of the degasification modules may include a hollow fiber membrane bundle having a plurality of hollow fiber membranes arranged around a liquid supply path through which a liquid is supplied and a cylinder which houses the hollow fiber membrane bundle and in which discharge ports for discharging the liquid are formed, and the degasification unit may have a connection supply pipe which connects the liquid supply paths of the plurality of degasification modules in series and in which openings through which the liquid passes are formed at positions corresponding to the plurality of degasification modules such that the liquid is supplied to the hollow fiber membrane bundles of the plurality of degasification modules in parallel.

A liquid degasification method according to an aspect of the present invention in any one of the above degasification systems includes degasifying a liquid by supplying the liquid from the inlet to the plurality of degasification units and depressurizing an inside of the plurality of hollow fiber membranes of each of the plurality of degasification units.

A degasification unit according to an aspect of the present invention used in any one of the above degasification systems includes a hollow fiber membrane bundle in which a plurality of hollow fiber membranes are bundled in a cylindrical shape; and a cylinder in which the hollow fiber membrane bundle is housed.

A degasification module according to an aspect of the present invention used in the above degasification system includes a hollow fiber membrane bundle having a plurality of hollow fiber membranes arranged around a liquid supply path through which a liquid is supplied; and a cylinder which houses the hollow fiber membrane bundle and in which discharge ports for discharging the liquid are formed.

A method for manufacturing a degasification system according to an aspect of the present invention is defined in claim <NUM>.

In this case, the method for manufacturing a degasification system may further include preparing a plurality of degasification modules each having a hollow fiber membrane bundle having a plurality of hollow fiber membranes arranged around a liquid supply path through which a liquid is supplied and a cylinder which houses the hollow fiber membrane bundle and in which discharge ports for discharging the liquid are formed, and a connection supply pipe in which a plurality of openings through which the liquid passes are formed; and inserting the connection supply pipe into the liquid supply paths of the plurality of degasification modules to connect the liquid supply paths of the plurality of degasification modules in series by the connection supply pipe and disposing the plurality of openings at positions corresponding to the plurality of degasification modules such that the liquid is supplied to the hollow fiber membrane bundles of the plurality of degasification modules in parallel, to manufacture the degasification unit.

A method for producing natural resources according to an aspect not of the present invention in any one of the degasification systems includes a degasification step of degasifying a liquid by supplying the liquid from the inlet to the plurality of degasification units and depressurizing an inside of the plurality of hollow fiber membranes of each of the plurality of degasification units; and a press-in step of pressing-in the liquid degasified in the degasification step into a natural resource mining site.

According to the aspect of the present invention, a degasification system capable of reducing deviation in the flow rate of a liquid flowing through a plurality of degasification units is provided.

Hereinafter, in the description based on the drawings, the same elements or similar elements having the same functions are designated by the same reference signs, and duplicate descriptions will be omitted.

The degasification system of the present embodiment is a system for degasifying a liquid. As the liquid to be degasified by the degasification system, water is exemplified. As shown in <FIG> and <FIG>, the degasification system <NUM> of the present embodiment includes a plurality of degasification units <NUM>, a housing <NUM> which houses the degasification unit <NUM>, and a suction pipe <NUM> (see <FIG>).

For example, the degasification unit <NUM> may be constituted by a plurality of degasification modules <NUM> being connected to each other as in a degasification unit 2A shown in <FIG> and may be constituted by one degasification module <NUM> as in a degasification unit 2B shown in <FIG>. The degasification unit 2A shown in <FIG> and the degasification unit 2B shown in <FIG> each show an example of the degasification unit <NUM>. Further, in <FIG> and <FIG>, to make the drawings easier to see, only one of the plurality of degasification units <NUM> is illustrated, and the remaining degasification units <NUM> are omitted.

As shown in <FIG> and <FIG>, the degasification module <NUM> includes, for example, a module inner pipe <NUM>, a hollow fiber membrane bundle <NUM>, and a module container (a cylinder) <NUM>.

The module inner pipe <NUM> is a pipe on an inner peripheral side of which a liquid supply path <NUM> to which a liquid such as water is supplied is formed. The module inner pipe <NUM> is formed, for example, in a circular pipe shape extending linearly. A plurality of inner pipe openings 11a are formed in the module inner pipe <NUM>. The inner pipe openings 11a are for passing the liquid supplied to the liquid supply path <NUM> of the module inner pipe <NUM>. The number, the positions, the sizes, and the like of the inner pipe openings 11a are not particularly limited.

The hollow fiber membrane bundle <NUM> has a plurality of hollow fiber membranes <NUM> arranged around the module inner pipe <NUM>. Therefore, the liquid supply path <NUM> is disposed on the inner peripheral side of the hollow fiber membrane bundle <NUM>. The hollow fiber membrane bundle <NUM> is configured by, for example, the plurality of hollow fiber membranes <NUM> being bundled in a cylindrical shape such as a circular cylindrical shape. The hollow fiber membrane <NUM> is a hollow fiber-like membrane that allows a gas to permeate but does not allow a liquid to permeate. Then, in the hollow fiber membrane bundle <NUM>, the inside of the hollow fiber membrane <NUM> is depressurized, and thus the liquid flowing out from the inner pipe openings 11a of the module inner pipe <NUM> is degasified.

A material, a membrane shape, a membrane form, and the like of the hollow fiber membrane <NUM> are not particularly limited. Examples of the material of the hollow fiber membrane <NUM> include polyolefin-based resins such as polypropylene and poly(<NUM>-methylpentene-<NUM>), silicone-based resins such as polydimethylsiloxane and copolymers thereof, and fluorine-based resins such as PTFE and vinylidene fluoride. Examples of the membrane shape (a side wall shape) of the hollow fiber membrane <NUM> include a porous membrane, a microporous membrane, and a homogeneous membrane having no porous material (a non-porous membrane). Examples of the membrane form of the hollow fiber membrane <NUM> include a symmetric membrane (a homogeneous membrane) in which a chemical or physical structure of the entire membrane is homogeneous and an asymmetric membrane (an inhomogeneous membrane) in which chemical or physical structures of the membrane differ depending on a portion of the membrane. The asymmetric membrane (the inhomogeneous membrane) is a membrane having a non-porous dense layer and the porous material. In this case, the dense layer may be formed in any portion of the membrane such as a surface layer portion of the membrane or the inside of the porous membrane. The inhomogeneous membrane also includes a composite film having different chemical structures and a multilayer structure film such as a three-layer structure.

The hollow fiber membrane bundle <NUM> can be formed, for example, by a woven fabric (not shown) in which the plurality of hollow fiber membranes <NUM> which are weft threads are woven with warp threads. This woven fabric is also called a hollow fiber membrane sheet, and the plurality of hollow fiber membranes <NUM> are woven in a bamboo blind shape. This woven fabric is constituted by, for example, <NUM> to <NUM> hollow fiber membranes <NUM> per inch. Then, it is possible to configure the hollow fiber membrane bundle <NUM> in a circular cylindrical shape by winding the woven fabric around the module inner pipe <NUM> (the periphery of the liquid supply path) such that the plurality of hollow fiber membranes <NUM> extend in an axial direction of the module inner pipe <NUM> (the liquid supply path <NUM>).

The module container <NUM> is a container that houses the hollow fiber membrane bundle <NUM>. A region between the module inner pipe <NUM> and the module container <NUM> is a degasification region A in which the liquid is degasified by the hollow fiber membrane bundle <NUM>. The module container <NUM> is formed, for example, in a circular cylindrical shape extending in the axial direction of the module inner pipe <NUM> (the liquid supply path <NUM>), and both ends thereof are open. A plurality of discharge ports 13a are formed in the module container <NUM>. The discharge ports 13a are for discharging the liquid that has passed through the hollow fiber membrane bundle <NUM> in the degasification region A from the module container <NUM> (the degasification module <NUM>). The number, the positions, the sizes, and the like of the discharge ports 13a are not particularly limited.

As shown in <FIG>, end portions 12a on both sides of the hollow fiber membrane bundle <NUM> are fixed to the module inner pipe <NUM> and the module container <NUM> by a sealing portion <NUM>.

The sealing portion <NUM> is formed of, for example, a resin. Examples of the resin used for the sealing portion <NUM> include an epoxy resin, a urethane resin, an ultraviolet curable resin, and a polyolefin resin such as polyethylene and polypropylene. The sealing portion <NUM> fills the entire region between the module inner pipe <NUM> and the module container <NUM> except for the inside of the hollow fiber membrane <NUM>. That is, the sealing portion <NUM> fills a portion between the hollow fiber membranes <NUM>, a portion between the hollow fiber membrane bundle <NUM> and the module inner pipe <NUM>, and a portion between the hollow fiber membranes <NUM> and the module container <NUM>, but does not fill the inside of the hollow fiber membrane <NUM>. Therefore, the inside of the hollow fiber membrane <NUM> is open from the sealing portion <NUM> to both end sides of the degasification module <NUM>, and it is possible to suction the inside of the hollow fiber membrane <NUM> from both end sides of the degasification module <NUM>. That is, openings at both ends of the module container <NUM> are suction openings that open or expose the inside of the hollow fiber membrane <NUM> to allow suctioning and depressurizing of the inside of the hollow fiber membrane <NUM>.

As shown in <FIG> and <FIG>, the degasification unit 2A constituted by the plurality of degasification modules <NUM> being connected to each other has, for example, a connection supply pipe 6A that connects the liquid supply paths <NUM> of the plurality of degasification modules <NUM> in series. The connection supply pipe 6A is one long pipe connected to the plurality of degasification modules <NUM>, and the liquid supply paths <NUM> of the plurality of degasification modules <NUM> are formed on an inner peripheral side thereof. Therefore, the plurality of degasification modules <NUM> are connected in series by the connection supply pipe 6A in appearance. The number of degasification modules <NUM> constituting the degasification unit 2A is not particularly limited, but will be described below as an example in which four degasification modules <NUM> are connected. The four degasification modules <NUM> are referred to as a degasification module 5A, a degasification module 5B, a degasification module 5C, and a degasification module 5D in the order of a flow direction of the liquid in the connection supply pipe 6A. The degasification module 5A is a degasification module <NUM> which is disposed on the furthest upstream side, and the degasification module 5D is a degasification module <NUM> which is disposed on the furthest downstream side. The degasification unit 2A is erected in the vertical direction, for example, such that the liquid flows from the bottom to the top in the connection supply pipe 6A. In this case, the degasification module 5A which is disposed on the furthest upstream side is disposed on the lowermost side, and the degasification module 5D which is disposed on the furthest downstream side is disposed on the uppermost side.

A supply port 6a through which the liquid is supplied to the connection supply pipe 6A is formed at an upstream end of the connection supply pipe 6A. A downstream end of the connection supply pipe 6A is sealed. The inner peripheral side of the connection supply pipe 6A forming the liquid supply paths <NUM> of the plurality of degasification modules <NUM> is penetrated from an upstream side to a downstream side. Therefore, on the inner peripheral side of the connection supply pipe 6A (the module inner pipe <NUM> of each degasification module <NUM>), a member that becomes a resistance to the flow of the liquid may be disposed, but a member that seals the connection supply pipe 6A to block the flow of the liquid is not disposed. Then, the liquid supplied from the supply port 6a is supplied to the liquid supply paths <NUM> of the plurality of degasification modules <NUM> in series by the connection supply pipe 6A.

In the connection supply pipe 6A, openings 6b through which the liquid passes are formed at positions corresponding to the plurality of degasification modules <NUM> such that the liquid is supplied to the hollow fiber membrane bundles <NUM> of the plurality of degasification modules <NUM> in parallel. Therefore, the liquid supplied to the supply port 6a of the connection supply pipe 6A is supplied (flows out) to the degasification region A of each degasification module <NUM> from the openings 6b formed at a position corresponding to each degasification module <NUM>. Accordingly, the liquid is supplied to the hollow fiber membrane bundles <NUM> of the plurality of degasification modules <NUM> in parallel.

Each degasification module <NUM> and the connection supply pipe 6A may be in close contact with each other or may be separated from each other. In a case in which each degasification module <NUM> and the connection supply pipe 6A are in close contact with each other, the inner pipe openings 11a of each degasification module <NUM> and the openings 6b of the connection supply pipe 6A are formed at positions where they overlap at least in part, and thus it is possible to supply the liquid from the connection supply pipe 6A to the degasification region A of each degasification module <NUM>. On the other hand, in a case in which each degasification module <NUM> and the connection supply pipe 6A are separated from each other, a flow path through which the liquid flows is formed in a space therebetween, and thus it is possible to supply the liquid from the connection supply pipe 6A to the degasification region A of each degasification module <NUM> regardless of a positional relationship between the inner pipe openings 11a of each degasification module <NUM> and the openings 6b of the connection supply pipe 6A.

As shown in <FIG> and <FIG>, the degasification unit 2B constituted by one degasification module <NUM> has, for example, a connection supply pipe 6B that is inserted into the module inner pipe <NUM> of the degasification module <NUM> to form the liquid supply path <NUM> of the degasification module <NUM> on the inner peripheral side thereof.

A supply port 6a through which the liquid is supplied to the connection supply pipe 6B is formed at an upstream end of the connection supply pipe 6B. A downstream end of the connection supply pipe 6B is sealed. The inner peripheral side of the connection supply pipe 6B forming the liquid supply path <NUM> of the degasification module <NUM> is penetrated from an upstream side to a downstream side. Therefore, on the inner peripheral side of the connection supply pipe 6B (the module inner pipe <NUM> of the degasification module <NUM>), a member that becomes a resistance to the flow of the liquid may be disposed, but a member that seals the connection supply pipe 6B to block the flow of the liquid is not disposed. Then, the liquid supplied from the supply port 6a is supplied to the liquid supply path <NUM> of the degasification module <NUM> by the connection supply pipe 6B.

In the connection supply pipe 6B, openings 6b through which the liquid passes are formed such that the liquid is supplied to the hollow fiber membrane bundle <NUM> of the degasification module <NUM>. Therefore, the liquid supplied to the supply port 6a of the connection supply pipe 6B is supplied (flows out) to the degasification region A of the degasification module <NUM> from the openings 6b. Accordingly, the liquid is supplied to the hollow fiber membrane bundle <NUM> of the degasification module <NUM>.

The degasification module <NUM> and the connection supply pipe 6B may be in close contact with each other or may be separated from each other. In a case in which the degasification module <NUM> and the connection supply pipe 6B are in close contact with each other, the inner pipe openings 11a of the degasification module <NUM> and the openings 6b of the connection supply pipe 6B are formed at positions where they overlap at least in part, and thus it is possible to supply the liquid from the connection supply pipe 6B to the degasification region A of the degasification module <NUM>. On the other hand, in a case in which the degasification module <NUM> and the connection supply pipe 6B are separated from each other, a flow path through which the liquid flows is formed in a space therebetween, and thus it is possible to supply the liquid from the connection supply pipe 6B to the degasification region A of the degasification module <NUM> regardless of a positional relationship between the inner pipe openings 11a of the degasification module <NUM> and the openings 6b of the connection supply pipe 6B.

Unless otherwise specified, the connection supply pipe 6A and the connection supply pipe 6B are collectively referred to as a connection supply pipe <NUM>. Further, the degasification unit 2B may not be provided with the connection supply pipe 6B, and the module inner pipe <NUM> may also serve as the connection supply pipe 6B. In this case, for example, a supply port through the liquid is supplied to the module inner pipe <NUM> is formed at the upstream end of the module inner pipe <NUM>, and the downstream end of the module inner pipe <NUM> is sealed.

As shown in <FIG>, the housing <NUM> is formed in a cylindrical shape. The housing <NUM> houses a plurality of degasification units <NUM> in parallel such that the plurality of degasification units <NUM> are disposed in parallel with a central axis L of the housing <NUM>.

An inlet 3a is formed, for example, at a lower end portion of the housing <NUM>. The inlet 3a communicates with the supply port 6a of each degasification unit <NUM>. Therefore, the liquid supplied from the inlet 3a is supplied to the liquid supply path <NUM> of each degasification unit <NUM> from the supply port 6a of each degasification unit <NUM>.

An outlet 3b is formed, for example, at an upper end portion of the housing <NUM>. The outlet 3b communicates with the discharge ports 13a of each degasification unit <NUM>. Therefore, the liquid discharged from the discharge ports 13a of each degasification unit <NUM> is discharged from the outlet 3b of the housing <NUM>.

The housing <NUM> is provided with a housing sealing portion (a sealing portion) <NUM> and a degasification unit supporting portion <NUM>.

The housing sealing portion <NUM> fixes an upstream end portion (a lower end portion) of the connection supply pipe <NUM> (the connection supply pipe 6A or the connection supply pipe 6B) to an inner peripheral surface of the housing <NUM>. Further, the housing sealing portion <NUM> partitions an internal space of the housing <NUM> into an upstream side region B on the inlet 3a side and a downstream side region C on the outlet 3b side via the plurality of degasification units <NUM>. As the housing sealing portion <NUM>, for example, a resin lined with a metal such as stainless steel, a fiber reinforced plastic (FRP), or a metal such as iron is used.

The housing sealing portion <NUM> fills the entire region between the connection supply pipe <NUM> and the housing <NUM> except for the inside of the connection supply pipe <NUM>. That is, the housing sealing portion <NUM> fills a portion between the connection supply pipe <NUM> and the housing <NUM>, but does not fill the inside of the connection supply pipe <NUM>. Therefore, the inside of the connection supply pipe <NUM> is opened from the supply port 6a to the upstream side region B. The liquid supplied from the inlet 3a to the upstream side region B is supplied to the inside of the connection supply pipe <NUM> from only the supply port 6a and is further supplied to the degasification region A of the degasification module <NUM> from the openings 6b and the inner pipe openings 11a.

Further, the housing sealing portion <NUM> is disposed on the upstream side of all the discharge ports 13a in the flow direction of the liquid flowing through the connection supply pipe <NUM>. Therefore, the inside of the module container <NUM> is opened from the discharge ports 13a to the downstream side region C. The liquid supplied from the openings 6b and the inner pipe openings 11a to the degasification region A is discharged to the downstream side region C from only the discharge ports 13a and is further discharged to the outside of the housing <NUM> from the outlet 3b.

The degasification unit supporting portion <NUM> is fixed to a downstream end portion (an upper end portion) of the degasification unit <NUM> and the housing <NUM> and supports the downstream end portion of the degasification unit <NUM>. The degasification unit supporting portion <NUM> is formed, for example, in a rod shape extending from the degasification unit <NUM> to the housing <NUM> and does not seal a portion between the degasification unit <NUM> and the housing <NUM>. Therefore, the liquid discharged from the discharge ports 13a to the downstream side region C is discharged from the outlet 3b to the outside of the housing <NUM> without being blocked by the degasification unit supporting portion <NUM>.

The inner diameter of the housing <NUM> is not particularly limited, but is preferably <NUM> or more and <NUM> or less, more preferably <NUM> or more and <NUM> or less, and further preferably <NUM> or more and <NUM> or less, for example.

The diameter of the degasification unit <NUM> is not particularly limited, but is preferably <NUM> or more and <NUM> or less, more preferably <NUM> or more and <NUM> or less, and further preferably <NUM> or more and <NUM> or less, for example. The diameter of the degasification unit <NUM> refers to the diameter of the module container <NUM>.

The number of degasification units <NUM> housed in the housing <NUM> is not particularly limited, but from the viewpoint of being able to ensure an installability of the degasification system <NUM> and to increase the flow rate, is preferably <NUM> or more and <NUM> or less, more preferably <NUM> or more and <NUM> or less, and further preferably <NUM> or more and <NUM> or less, for example.

The flow rate of the liquid which is supplied to the housing <NUM> is not particularly limited, but from the viewpoint of being able to improve degasification efficiency of the degasification unit <NUM>, is preferably <NUM><NUM>/h or more and <NUM><NUM>/h or less, more preferably <NUM><NUM>/h or more and <NUM><NUM>/h or more, and further preferably <NUM><NUM>/h or more and <NUM><NUM>/h or less, for example.

The ideal retention time of the liquid in the housing <NUM> is not particularly limited, but from the viewpoint of being able to increase the flow rate while preventing the housing <NUM> from becoming too large, is preferably <NUM> seconds or more and <NUM> seconds or less, more preferably <NUM> seconds or more and <NUM> seconds or less, and further preferably <NUM> seconds or more and <NUM> seconds or less, for example. The ideal retention time of the liquid in the housing <NUM> refers to a value (V/Q) obtained by dividing the volume Vm<NUM> of the housing <NUM> by the flow rate Qm<NUM>/h of the liquid.

The ideal retention time of the liquid in the upstream side region B is not particularly limited, but from the viewpoint of appropriately supplying the liquid to each degasification unit <NUM> while preventing the degasification system <NUM> from becoming too large, is preferably <NUM> seconds or more and <NUM> seconds or less, more preferably <NUM> seconds or more and <NUM> seconds or less, and further preferably <NUM> seconds or more and <NUM> seconds or less, for example. The ideal retention time of the liquid in the upstream side region B refers to a value (V/Q) obtained by dividing the volume Vm<NUM> of the upstream side region B by the flow rate Qm<NUM>/h of the liquid.

The suction pipe <NUM> communicates with the inside of the hollow fiber membrane <NUM> to suction (to vacuum-evacuate) the inside of the hollow fiber membrane <NUM>. Further, the suction pipe <NUM> penetrates the housing <NUM> and extends to the outside of the housing <NUM> for the suction by a suction pump such as a vacuum pump provided outside the housing <NUM>. As described above, the inside of the hollow fiber membrane <NUM> is opened from the sealing portion <NUM> to both end sides of the degasification module <NUM>. Therefore, the suction pipe <NUM> is connected to both ends of the degasification module <NUM> to which the inside of the hollow fiber membrane <NUM> is opened. Accordingly, it is possible to suction the inside of the hollow fiber membrane <NUM> from both end sides of the degasification module <NUM> by suctioning the suction pipe <NUM>.

Further, in the degasification unit 2A shown in <FIG>, since the plurality of degasification modules <NUM> are connected in series by the connection supply pipe <NUM> in appearance, end faces of the degasification modules on opposite sides are disposed to face each other between the degasification modules <NUM> adjacent to each other along the connection supply pipe <NUM>. Therefore, one suction pipe <NUM> may be connected to the facing end faces.

The suction pipe <NUM> may be provided for each of the plurality of degasification units <NUM>, or may be provided in one for the plurality of degasification units <NUM>. Further, in a case in which one degasification unit <NUM> is constituted by the plurality of degasification modules <NUM> as in the degasification unit 2A shown in <FIG>, the suction pipe <NUM> may be connected to each of the plurality of degasification modules <NUM>, or one suction pipe <NUM> may be connected to the plurality of degasification modules <NUM>. Further, in the degasification unit 2A shown in <FIG>, since the plurality of degasification modules <NUM> are connected in series by the connection supply pipe <NUM> in appearance, end faces of the degasification modules on opposite sides are disposed to face each other between the degasification modules <NUM> adjacent to each other along the connection supply pipe <NUM>. Therefore, one suction pipe <NUM> may be connected to the facing end faces.

Next, a liquid degasification method by the degasification system <NUM> will be described.

First, a liquid such as water is supplied from the inlet 3a of the housing <NUM> to the upstream side region B of the housing <NUM>. Then, the liquid supplied to the upstream side region B is supplied to the connection supply pipe <NUM> from the supply port 6a and is supplied to the degasification region A of the degasification module <NUM> through the openings 6b of the connection supply pipe <NUM> and the inner pipe openings 11a of the degasification module <NUM>. Accordingly, the liquid is supplied to the hollow fiber membrane bundle <NUM> of the degasification module <NUM>. In the degasification region A, the liquid supplied from the inner pipe openings 11a passes between the plurality of hollow fiber membranes <NUM> in the hollow fiber membrane bundle <NUM> and then is discharged from the discharge ports 13a. At this time, the suction pipe <NUM> is suctioned, and the inside of the plurality of hollow fiber membranes <NUM> is depressurized, and thus a dissolved gas, bubbles, and the like of the liquid passing between the plurality of hollow fiber membranes <NUM> are removed. Then, the degasified liquid is discharged from the discharge ports 13a to the downstream side region C and further discharged from the outlet 3b to the outside of the housing <NUM>.

Here, the present inventors analyzed a flow rate of the liquid flowing through each degasification unit <NUM> for degasification systems <NUM> of Reference Examples <NUM> to <NUM> in which <NUM> degasification units <NUM> are housed in parallel in a housing <NUM> as shown in <FIG> shows only half of the degasification unit <NUM>. Each degasification unit <NUM> was set to be constituted by four degasification modules connected to each other as in the degasification unit 2A shown in <FIG>, and all the degasification units <NUM> were set to be the same.

In the degasification system <NUM>, the plurality of degasification units <NUM> were disposed in four rows from the central axis of the housing <NUM> toward the inner peripheral surface side of the housing <NUM>. Specifically, the degasification unit <NUM> which is disposed on the most central side was designated as a degasification unit 22A in a first row. The degasification unit <NUM> disposed on the outer peripheral side of the degasification unit 22A in the first row was designated as a degasification unit 22B in a second row. The degasification unit <NUM> which is disposed on the outer peripheral side of the degasification unit 22B in the second row was designated as a degasification unit 22C in a third row. The degasification unit <NUM> which is disposed on the outer peripheral side of the degasification unit 22C in the third row and is disposed on the outermost peripheral side was designated as a degasification unit 22D in a fourth row. The degasification unit 22A in the first row is constituted by one degasification unit <NUM> disposed on the central axis of the housing <NUM>. The degasification unit 22B in the second row is constituted by six degasification units <NUM> to surround the degasification unit 22A in the first row. The degasification unit 22C in the third row is constituted by <NUM> degasification units <NUM> to surround the degasification unit 22B in the second row. The degasification unit 22D in the fourth row is constituted by <NUM> degasification units <NUM> to surround the degasification unit 22C in the third row.

As analysis software, ANSYS Fluent Ver. <NUM> was used. For the liquid, seawater was used as a model, and a density thereof was set to <NUM>/m<NUM> and a viscosity thereof was set to <NUM> Pa·s. For the hollow fiber membrane bundle, a porous material (a flow path having a pressure resistance) was used as a model, and a pressure coefficient thereof was set to <NUM> × <NUM><NUM> from an analysis value of one degasification module. In the analysis for obtaining the pressure coefficient, EF-040P manufactured by DIC Corporation was used.

As shown in <FIG> and <FIG>, in the degasification system <NUM> of Reference Example <NUM>, the inner diameter of the housing <NUM> was set to <NUM>, the outer diameter D1 of the degasification unit <NUM> was set to <NUM>, and the distance D2 from the plurality of degasification units <NUM> to the inner peripheral surface of the housing <NUM> was set to <NUM>. The distance D2 from the plurality of degasification units <NUM> to the inner peripheral surface of the housing <NUM> refers to the shortest distance from the circumscribed circle of the plurality of degasification units <NUM> to the inner peripheral surface of the housing <NUM>. The distance D2 is about <NUM> times the outer diameter D1 of the degasification unit <NUM>. In other words, the ratio (D2/D1) of the distance D2 to the outer diameter D1 of the degasification unit <NUM> is about <NUM>. Further, the diameter of the inlet 3a of the housing <NUM> was set to <NUM>, and it was set such that all of the degasification unit 22A in the first row overlaps the inlet 3a, a part of the degasification unit 22B in the second row overlaps the inlet 3a, and the degasification unit 22C in the third row and the degasification unit 22D in the fourth row do not overlap the inlet 3a at all, when seen in a direction along the central axis of the housing <NUM>. Further, the total flow rate of the liquid which is supplied to the degasification system <NUM> was set to <NUM><NUM>/h, and the ideal retention time of the liquid in the upstream side region B (see <FIG>) of the housing <NUM> was set to <NUM> seconds.

As shown in <FIG> and <FIG>, in the degasification system <NUM> of Reference Example <NUM>, the inner diameter of the housing <NUM> was set to <NUM>, the outer diameter D1 of the degasification unit <NUM> was set to <NUM>, and the distance D2 from the plurality of degasification units <NUM> to the inner peripheral surface of the housing <NUM> was set to <NUM>. The distance D2 is about <NUM> times the outer diameter D1 of the degasification unit <NUM>. In other words, the ratio (D2/D1) of the distance D2 to the outer diameter D1 of the degasification unit <NUM> is about <NUM>. Further, the diameter of the inlet 3a of the housing <NUM> was set to <NUM>, and it was set such that all of the degasification unit 22A in the first row overlaps the inlet 3a, a part of the degasification unit 22B in the second row overlaps the inlet 3a, and the degasification unit 22C in the third row and the degasification unit 22D in the fourth row do not overlap the inlet 3a at all, when seen in a direction along the central axis of the housing <NUM>. Further, the total flow rate of the liquid which is supplied to the degasification system <NUM> was set to <NUM><NUM>/h, and the ideal retention time of the liquid in the upstream side region B of the housing <NUM> was set to <NUM> seconds.

As shown in <FIG> and <FIG>, in the degasification system <NUM> of Reference Example <NUM>, the inner diameter of the housing <NUM> was set to <NUM>, the outer diameter D1 of the degasification unit <NUM> was set to <NUM>, and the distance D2 from the plurality of degasification units <NUM> to the inner peripheral surface of the housing <NUM> was set to <NUM>. The distance D2 is about <NUM> times the outer diameter D1 of the degasification unit <NUM>. In other words, the ratio (D2/D1) of the distance D2 to the outer diameter D1 of the degasification unit <NUM> is about <NUM>. Further, the diameter of the inlet 3a of the housing <NUM> was set to <NUM>, and it was set such that all of the degasification unit 22A in the first row and all of the degasification unit 22B in the second row overlap the inlet 3a, and the degasification unit 22C in the third row and the degasification unit 22D in the fourth row do not overlap the inlet 3a at all, when seen in a direction along the central axis of the housing <NUM>. Further, the total flow rate of the liquid which is supplied to the degasification system <NUM> was set to <NUM><NUM>/h, and the ideal retention time of the liquid in the upstream side region B of the housing <NUM> was set to <NUM> seconds.

As shown in <FIG> and <FIG>, in the degasification system <NUM> of Reference Example <NUM>, the inner diameter of the housing <NUM> was set to <NUM>, the outer diameter D1 of the degasification unit <NUM> was set to <NUM>, and the distance D2 from the plurality of degasification units <NUM> to the inner peripheral surface of the housing <NUM> was set to <NUM>. The distance D2 is about <NUM> times the outer diameter D1 of the degasification unit <NUM>. In other words, the ratio (D2/D1) of the distance D2 to the outer diameter D1 of the degasification unit <NUM> is about <NUM>. Further, the diameter of the inlet 3a of the housing <NUM> was set to <NUM>, and it was set such that all of the degasification unit 22A in the first row overlaps the inlet 3a, a part of the degasification unit 22B in the second row overlaps the inlet 3a, and the degasification unit 22C in the third row and the degasification unit 22D in the fourth row do not overlap the inlet 3a at all, when seen in a direction along the central axis of the housing <NUM>. Further, the total flow rate of the liquid which is supplied to the degasification system <NUM> was set to <NUM><NUM>/h, and the ideal retention time of the liquid in the upstream side region B of the housing <NUM> was set to <NUM> seconds. The ideal retention time of the upstream side region B of Reference Example <NUM> is <NUM> times the ideal retention time of the upstream side region B of Reference Example <NUM>. In other words, the ratio (T6/T2) of the ideal retention time T6 of the upstream side region B of Reference Example <NUM> to the ideal retention time T2 of the upstream side region B of Reference Example <NUM> is <NUM>.

As shown in <FIG> and <FIG>, in the degasification system <NUM> of Reference Example <NUM>, the inner diameter of the housing <NUM> was set to <NUM>, the outer diameter D1 of the degasification unit <NUM> was set to <NUM>, and the distance D2 from the plurality of degasification units <NUM> to the inner peripheral surface of the housing <NUM> was set to <NUM>. The distance D2 is about <NUM> times the outer diameter D1 of the degasification unit <NUM>. In other words, the ratio (D2/D1) of the distance D2 to the outer diameter D1 of the degasification unit <NUM> is about <NUM>. Further, the diameter of the inlet 3a of the housing <NUM> was set to <NUM>, and it was set such that all of the degasification unit 22A in the first row overlaps the inlet 3a, a part of the degasification unit 22B in the second row overlaps the inlet 3a, and the degasification unit 22C in the third row and the degasification unit 22D in the fourth row do not overlap the inlet 3a at all, when seen in a direction along the central axis of the housing <NUM>. Further, the total flow rate of the liquid which is supplied to the degasification system <NUM> was set to <NUM><NUM>/h, and the ideal retention time of the liquid in the upstream side region B of the housing <NUM> was set to <NUM> seconds. The ideal retention time of the upstream side region B of Reference Example <NUM> is <NUM> times the ideal retention time of the upstream side region B of Reference Example <NUM>. In other words, the ratio (T7/T2) of the ideal retention time T7 of the upstream side region B of Reference Example <NUM> to the ideal retention time T2 of the upstream side region B of Reference Example <NUM> is <NUM>.

As shown in <FIG> and <FIG>, in the degasification system <NUM> of Reference Example <NUM>, the inner diameter of the housing <NUM> was set to <NUM>, the outer diameter D1 of the degasification unit <NUM> was set to <NUM>, and the distance D2 from the plurality of degasification units <NUM> to the inner peripheral surface of the housing <NUM> was set to <NUM>. The distance D2 is about <NUM> times the outer diameter D1 of the degasification unit <NUM>. In other words, the ratio (D2/D1) of the distance D2 to the outer diameter D1 of the degasification unit <NUM> is about <NUM>. Further, the diameter of the inlet 3a of the housing <NUM> was set to <NUM>, and it was set such that all of the degasification unit 22A in the first row overlaps the inlet 3a, a part of the degasification unit 22B in the second row overlaps the inlet 3a, and the degasification unit 22C in the third row and the degasification unit 22D in the fourth row do not overlap the inlet 3a at all, when seen in a direction along the central axis of the housing <NUM>. Further, the total flow rate of the liquid which is supplied to the degasification system <NUM> was set to <NUM><NUM>/h, and the ideal retention time of the liquid in the upstream side region B of the housing <NUM> was set to <NUM> seconds. The ideal retention time of the upstream side region B of Reference Example <NUM> is <NUM> times the ideal retention time of the upstream side region B of Reference Example <NUM>. In other words, the ratio (T8/T2) of the ideal retention time T8 of the upstream side region B of Reference Example <NUM> to the ideal retention time T2 of the upstream side region B of Reference Example <NUM> is <NUM>.

The flow rates of the degasification units <NUM> in each row in Reference Examples <NUM> to <NUM> are shown in <FIG>. As the flow rate of the degasification unit 22B in the second row, the flow rate of the degasification unit 22C in the third row, and the flow rate of the degasification unit 22D in the fourth row, an average value of the flow rates of all the degasification units <NUM> disposed in each row was used.

<FIG> is a graph showing the relationship between the flow rates of the degasification units <NUM> in each row and the ratio (D2/D1) of the distance D2 to the outer diameter D1 of the degasification unit <NUM> in Reference Examples <NUM> to <NUM>. As shown in <FIG>, as a whole, the flow rate of the degasification unit <NUM> tends to increase as the degasification unit <NUM> is close to the central axis of the housing <NUM>, and the flow rate of the degasification unit <NUM> tends to decrease as the degasification unit <NUM> becomes further away from the central axis of the housing <NUM>.

Therefore, it is assumed that by increasing a pressure loss of the liquid flowing through the degasification unit <NUM> as the degasification unit <NUM> is close to the central axis of the housing <NUM>, it is possible to reduce deviation in the flow rate of the liquid flowing through each degasification unit <NUM>.

On the other hand, in Reference Examples <NUM> and <NUM>, the magnitude relationship between the flow rate of the degasification unit 22C in the third row and the flow rate of the degasification unit 22D in the fourth row is reversed. That is, in Reference Examples <NUM> and <NUM>, the flow rate of the degasification unit 22D in the fourth row is larger than the flow rate of the degasification unit 22C in the third row. From a line connecting the flow rates of the degasification units <NUM> in each row in Reference Examples <NUM> to <NUM>, it can be seen that the magnitude relationship between the flow rate of the degasification unit 22C in the third row and the flow rate of the degasification unit 22D in the fourth row is reversed at a point where the ratio (D2/D1) of the distance D2 to the outer diameter D1 of the degasification unit <NUM> is <NUM>.

From this result, it was found that the flow rate of the liquid flowing through the degasification unit <NUM> tends to decrease as the degasification unit <NUM> becomes further away from the central axis of the housing <NUM>, but the above tendency is reversed in an outer region from the inner peripheral surface of the housing <NUM> to a position corresponding to <NUM> times or <NUM> times the outer diameter D1 of the degasification unit <NUM> toward the central axis side. That is, it was found that the flow rate of the liquid flowing through the degasification unit <NUM> tends to be higher in the outer region than in an inner region. Further, it was found that in the outer region, the flow rate of the liquid flowing through the degasification unit <NUM> tends to increase as the degasification unit <NUM> becomes further away from the central axis of the housing <NUM> (as the degasification unit <NUM> is close to the inner peripheral surface of the housing <NUM>). It is assumed that this is because, in the outer region, the liquid flowing in the housing <NUM> is pushed back against the inner peripheral surface of the housing <NUM>, and thus the flow rate of the liquid flowing through the degasification unit <NUM> increases.

Therefore, it is assumed that by making the pressure loss of the liquid in the degasification unit <NUM> disposed in the outer region <NUM> larger than that in the degasification unit <NUM> closest to the outer region <NUM> among the degasification units <NUM> disposed in the inner region <NUM>, it is possible to reduce deviation in the flow rate of the liquid flowing through each degasification unit <NUM>. Further, it is assumed that in the outer region, by increasing the pressure loss of the liquid flowing through the degasification unit <NUM> as the degasification unit <NUM> becomes further away from the central axis of the housing <NUM>, it is possible to reduce deviation in the flow rate of the liquid flowing through each degasification unit <NUM>.

<FIG> is a graph showing the relationship between each row and the flow rates of degasification units <NUM> in Reference Examples <NUM> and <NUM>. As shown in <FIG>, in Reference Example <NUM> and Reference Example <NUM>, the degree of overlap between the degasification unit <NUM> and the inlet 3a when seen in a direction along the central axis of the housing <NUM> is different. However, as shown in <FIG>, in both Reference Example <NUM> and Reference Example <NUM>, the tendency that the flow rate of the degasification unit <NUM> that overlaps the inlet 3a when seen in a direction along the central axis of the housing <NUM> is larger than that of the degasification unit <NUM> that does not overlap the inlet 3a when seen in a direction along the central axis of the housing <NUM> does not change.

From this result, it was found that the flow rate of the degasification unit <NUM> that overlaps the inlet 3a when seen in a direction along the central axis of the housing <NUM> is larger than that of the degasification unit <NUM> that does not overlap the inlet 3a when seen in a direction along the central axis of the housing <NUM> regardless of the difference in the degree of overlap between the degasification unit <NUM> and the inlet 3a when seen in a direction along the central axis of the housing <NUM>.

Therefore, it is assumed that by making the pressure loss of the liquid in the degasification unit <NUM> that overlaps the inlet 3a when seen in a direction along the central axis of the housing <NUM> larger than that in the degasification unit <NUM> that does not overlap the inlet 3a when seen in a direction along the central axis of the housing <NUM> regardless of the difference in the degree of overlap between the degasification unit <NUM> and the inlet 3a when seen in a direction along the central axis of the housing <NUM>, it is possible to reduce deviation in the flow rate of the liquid flowing through each degasification unit <NUM>.

<FIG> is a graph showing the relationship between the flow rates of degasification units <NUM> in each row and the ideal retention time of the upstream side region B of the housing <NUM> in Reference Examples <NUM> to <NUM>. As shown in <FIG>, in Reference Examples <NUM> to <NUM>, the ideal retention time of the upstream side region B of the housing <NUM> is different. However, in all of Reference Examples <NUM> to <NUM>, the tendency that the flow rate of the liquid flowing through the degasification unit <NUM> increases as the degasification unit <NUM> is close to the central axis of the housing <NUM> does not change.

From this result, it was found that the flow rate of the liquid flowing through the degasification unit <NUM> increases as the degasification unit <NUM> is close to the central axis of the housing <NUM> regardless of the difference in the ideal retention time of the upstream side region B of the housing <NUM>.

Therefore, it is assumed that by increasing the pressure loss of the liquid flowing through the degasification unit <NUM> as the degasification unit <NUM> is close to the central axis of the housing <NUM> regardless of the difference in the ideal retention time of the upstream side region B, it is possible to reduce deviation in the flow rate of the liquid flowing through each degasification unit <NUM>.

In view of the analysis results and examinations of the above reference example, in the present embodiment, the plurality of degasification units <NUM> are configured such that the pressure losses of the liquid differ depending on the distance from the central axis L of the housing <NUM>, and thus the deviation in the flow rate of the liquid flowing through each degasification unit <NUM> is reduced, and the degasification performance of the degasification system <NUM> in its entirety is improved.

Specifically, among the plurality of degasification units <NUM>, the degasification unit <NUM> that overlaps the inlet 3a when seen in a direction along the central axis L may be configured such that the pressure loss of the liquid therein is larger than that in the degasification unit <NUM> that does not overlap the inlet 3a when seen in a direction along the central axis L of the housing <NUM> (see Reference Examples <NUM> and <NUM> and <FIG>). In the present specification, the pressure loss refers to a pressure loss of the liquid flowing through the degasification unit <NUM>.

Here, as shown in <FIG>, a region from the inner peripheral surface 3c of the housing <NUM> to a position of a predetermined distance D toward the central axis L side is defined as the outer region <NUM>, and a region inside the outer region <NUM> is defined as the inner region <NUM>. This predetermined distance D is a distance at which the magnitude relationship of the flow rates of the degasification units <NUM> is reversed in a case in which the pressure losses of the plurality of degasification units <NUM> are the same. From the above Examination <NUM>, the predetermined distance may be <NUM> times the outer diameter D1 of the degasification unit <NUM> or <NUM> times the outer diameter D1 of the degasification unit <NUM>.

In this case, in the inner region <NUM>, the plurality of degasification units <NUM> have an inner degasification unit which is an arbitrary one degasification unit <NUM> and an outer degasification unit which is a degasification unit <NUM> farther from the central axis L than the inner degasification unit and the inner degasification unit may be configured such that the pressure loss of the liquid therein is larger than that in the outer degasification unit (see Reference Examples <NUM> to <NUM> and <FIG>). For example, in a case in which all the degasification modules are disposed in the inner region <NUM> and the degasification unit 2A in the first row is set as an inner degasification module, any of the degasification unit 2B in the second row, the degasification unit 2C in the third row, and the degasification unit 2D in the fourth row serves as the outer degasification module. In the inner region <NUM>, it is sufficient that the pressure losses of any two degasification units <NUM> among the plurality of degasification units <NUM> satisfy the above relationship. For example, the pressure losses of the degasification units <NUM> adjacent to each other in a radial direction of the housing <NUM> may be the same (substantially the same). The fact that the pressure losses are the same means that it also includes a case in which the pressure losses differ by, for example, about <NUM>% due to a manufacturing error or the like.

Further, in a case in which all the degasification units <NUM> are disposed in the inner region <NUM>, the plurality of degasification units <NUM> may be configured such that the pressure loss of the liquid increases as the degasification unit <NUM> becomes closer to the central axis L.

On the other hand, in a case in which at least one degasification unit <NUM> is disposed in the outer region <NUM> and the remaining degasification units <NUM> are disposed in the inner region <NUM>, the degasification units <NUM> disposed in the inner region <NUM> may be configured such that the pressure loss of the liquid increases as the degasification unit <NUM> becomes closer to the central axis L. In this case, the degasification unit <NUM> disposed in the outer region <NUM> may be configured such that the pressure loss of the liquid therein is larger than that in the degasification unit <NUM> closest to the outer region <NUM> among the degasification units <NUM> disposed in the inner region <NUM>. Further, the degasification units <NUM> disposed in the outer region <NUM> may be configured such that the pressure loss of the liquid increases as the degasification unit <NUM> becomes further away from the central axis L of the housing <NUM>.

It is possible to obtain the pressure loss of the liquid flowing through the degasification unit <NUM>, for example, by measuring the pressure of the liquid in the supply port 6a (see <FIG> and <FIG>) and the pressure of the liquid in each of the discharge ports 13a (see <FIG> and <FIG>) of the degasification unit <NUM> with a pressure gauge or the like and calculating the difference therebetween.

Here, the pressure loss of the liquid in each degasification unit <NUM> is the sum of, for example, [<NUM>] a pressure loss of the liquid in the liquid supply path <NUM> (the connection supply pipe <NUM>), [<NUM>] a pressure loss of the liquid in the openings 6b of the connection supply pipe <NUM>, [<NUM>] a pressure loss of the liquid in the inner pipe openings 11a of the module inner pipe <NUM>, [<NUM>] a pressure loss of the liquid in the hollow fiber membrane bundle <NUM>, and [<NUM>] a pressure loss of the liquid in the discharge ports 13a of the module container <NUM>. Therefore, for example, by adjusting a part or all of them, that is, by adjusting at least one of them, it is possible to adjust the pressure loss of the liquid in each degasification unit <NUM>.

Further, for example, by increasing the thickness of the hollow fiber membrane bundle <NUM> in the degasification module <NUM>, it is possible to increase the pressure loss of the liquid in the hollow fiber membrane bundle <NUM>. Specifically, when the thickness of the hollow fiber membrane bundle <NUM> is made thick, the passage resistance of the liquid to the hollow fiber membrane bundle <NUM> is increased. As a result, the pressure loss of the liquid in the hollow fiber membrane bundle <NUM> becomes large.

Further, in a case in which the hollow fiber membrane bundle <NUM> is formed by a woven fabric obtained by weaving the plurality of hollow fiber membranes <NUM>, which are weft threads, with warp threads being wound around the module inner pipe <NUM> (the periphery of the liquid supply path <NUM>), for example, by making the winding pressure of the woven fabric in the degasification module <NUM> high, it is possible to increase the pressure loss of the liquid in the hollow fiber membrane bundle <NUM>. Specifically, when the winding pressure of the wound woven fabric is made high, a gap between the plurality of hollow fiber membranes <NUM> is narrowed, and the passage resistance of the liquid to the hollow fiber membrane bundle <NUM> is increased. As a result, the pressure loss of the liquid in the hollow fiber membrane bundle <NUM> becomes large. In this case, the woven fabric may be wound around the module inner pipe <NUM> (the periphery of the liquid supply path <NUM>) such that the plurality of hollow fiber membranes <NUM> extend in the axial direction of the module inner pipe <NUM> (the liquid supply path <NUM>).

Similarly, in a case in which the hollow fiber membrane bundle <NUM> is formed by a woven fabric obtained by weaving the plurality of hollow fiber membranes <NUM>, which are weft threads, with warp threads being wound around the module inner pipe <NUM> (the periphery of the liquid supply path <NUM>) such that the plurality of hollow fiber membranes <NUM> extend in the axial direction of the module inner pipe <NUM> (the liquid supply path <NUM>), for example, by making a pitch between the warp threads in the degasification module <NUM> long, it is possible to increase the pressure loss of the liquid in the hollow fiber membrane bundle <NUM>. Specifically, when the woven fabric is wound around the module inner pipe <NUM>, the hollow fiber membrane <NUM> on the outer peripheral side tends to enter between the adjacent hollow fiber membranes <NUM> on the inner peripheral side. In this case, if the pitch between the warp threads in the degasification module <NUM> is short, a gap between the hollow fiber membranes on the inner peripheral side which are supported by the warp threads is narrowed, and thus the hollow fiber membrane <NUM> on the outer peripheral side is difficult to enter between the adjacent hollow fiber membranes <NUM> on the inner peripheral side. As a result, the density of the hollow fiber membranes <NUM> becomes low. As a result, the pressure loss of the liquid in the hollow fiber membrane bundle <NUM> becomes small. On the other hand, if the pitch between the warp threads in the degasification module <NUM> is long, a gap between the hollow fiber membranes on the inner peripheral side which are supported by the warp threads is lengthened, and thus the hollow fiber membrane <NUM> on the outer peripheral side easily enters between the adjacent hollow fiber membranes <NUM> on the inner peripheral side. As a result, the density of the hollow fiber membranes <NUM> becomes high. As a result, the pressure loss of the liquid in the hollow fiber membrane bundle <NUM> becomes large.

Further, for example, by increasing the outer diameter of the hollow fiber membrane <NUM> in the degasification module <NUM>, it is possible to increase the pressure loss of the liquid in the hollow fiber membrane bundle <NUM>. Specifically, for example, in a case in which the number of the hollow fiber membranes <NUM> is the same, when the outer diameter of the hollow fiber membrane <NUM> is made large, a gap between the hollow fiber membranes <NUM> is narrowed, and the passage resistance of the liquid to the hollow fiber membrane bundle <NUM> is increased. As a result, the pressure loss of the liquid in the hollow fiber membrane bundle <NUM> becomes large.

Further, for example, by making the hydrophilicity of the hollow fiber membrane <NUM> in the degasification module <NUM> high, it is possible to increase the pressure loss of the liquid in the hollow fiber membrane bundle <NUM>. Specifically, when the hydrophilicity of the hollow fiber membrane <NUM> is made high, the contact resistance of the liquid to the hollow fiber membrane <NUM> is increased. As a result, the pressure loss of the liquid in the hollow fiber membrane bundle <NUM> becomes large.

[<NUM>] For example, by reducing the total area of the discharge ports 13a of the degasification module <NUM>, reducing the number of the discharge ports 13a of the degasification module <NUM>, or reducing the size of each of the discharge ports 13a of the degasification module <NUM>, it is possible to increase the pressure loss of the liquid at the discharge ports 13a of the module container <NUM>.

As described above, in the degasification system <NUM> according to the present embodiment, the plurality of degasification units <NUM> are housed in parallel in the cylindrical housing <NUM>. Here, in a case in which the pressure losses of the liquid flowing through the plurality of degasification units <NUM> are the same, the flow rates of the liquid flowing through the degasification units <NUM> differ depending on the distance from the central axis L of the housing <NUM>. However, in this degasification system <NUM>, the plurality of degasification units <NUM> are configured such that the pressure losses of the liquid differ depending on the distance from the central axis L of the housing <NUM>. This difference in the pressure loss acts to offset the above difference in the flow rate. As a result, it is possible to reduce the deviation in the flow rate of the liquid flowing through the plurality of degasification units <NUM>. As a result, for example, the degasification performance of the degasification system <NUM> in its entirety can be improved.

Further, by providing the suction pipe <NUM>, it is possible to appropriately degasify the liquid in the degasification unit <NUM>, and it is possible to appropriately discharge the degasification gas to the outside of the housing <NUM>.

Since the degasification unit <NUM> that overlaps the inlet 3a when seen in a direction along the central axis L receives a stronger supply pressure of the liquid from the inlet 3a than that in the degasification unit <NUM> that does not overlap the inlet 3a when seen in a direction along the central axis L, the liquid easily flows in the degasification unit <NUM> that overlaps the inlet 3a when seen in a direction along the central axis L. Here, since the degasification unit <NUM> that overlaps the inlet 3a when seen in a direction along the central axis L is configured such that the pressure loss of the liquid therein is larger than that in the degasification unit <NUM> that does not overlap the inlet 3a when seen in a direction along the central axis L, this difference in the pressure loss acts to offset the difference in the supply pressure of the liquid. As a result, it is possible to reduce the deviation in the flow rate of the liquid flowing through these degasification units <NUM>.

Incidentally, as described above, in a case in which the pressure losses of the liquid flowing through the plurality of degasification units <NUM> are the same, the flow rate of the liquid flowing through the degasification unit <NUM> tends to decrease as the degasification unit <NUM> becomes further away from the central axis L of the housing <NUM>. However, the above tendency is reversed in the outer region from the inner peripheral surface of the housing <NUM> to the position of the predetermined distance D toward the central axis side.

Therefore, since the inner degasification unit is configured such that the pressure loss of the liquid therein is larger than that in the outer degasification unit, this difference in the pressure loss acts to offset the above difference in the flow rate. As a result, it is possible to reduce the deviation in the flow rate of the liquid flowing through the inner degasification unit and the outer degasification unit.

Further, in a case in which all the degasification units <NUM> are disposed in the inner region <NUM>, the plurality of degasification units <NUM> are configured such that the pressure loss of the liquid increases as the degasification unit <NUM> becomes closer to the central axis L, and thus it is possible to appropriately reduce the deviation in the flow rate of the liquid flowing through the plurality of degasification units <NUM>.

On the other hand, in a case in which at least one degasification unit <NUM> is disposed in the outer region <NUM> and the remaining degasification units <NUM> are disposed in the inner region <NUM>, the degasification units <NUM> disposed in the inner region <NUM> are configured such that the pressure loss of the liquid increases as the degasification unit <NUM> becomes closer to the central axis L, and thus it is possible to appropriately reduce the deviation in the flow rate of the liquid flowing through the degasification units <NUM> in the inner region <NUM>.

In this case, since the degasification unit <NUM> disposed in the outer region <NUM> is configured such that the pressure loss of the liquid therein is larger than that in the degasification unit <NUM> closest to the outer region <NUM> among the degasification units <NUM> disposed in the inner region <NUM>, it is possible to appropriately reduce the deviation in the flow rate of the liquid even between the degasification unit <NUM> disposed in the inner region <NUM> and the degasification unit <NUM> disposed in the outer region <NUM>.

Next, a method for manufacturing the degasification system <NUM> will be described.

In a case in which one degasification unit <NUM> is constituted by a plurality of degasification modules <NUM> as in the degasification unit 2A shown in <FIG>, first, a plurality of degasification modules <NUM> and a connection supply pipe <NUM> are prepared. Next, the connection supply pipe <NUM> is inserted into the liquid supply paths <NUM> of the plurality of degasification modules <NUM>. Then, the liquid supply paths <NUM> of the plurality of degasification modules <NUM> are connected in series by the connection supply pipe <NUM>. Further, the plurality of openings 6b of the connection supply pipe <NUM> are disposed at positions corresponding to the plurality of degasification modules <NUM> such that the liquid is supplied to the hollow fiber membrane bundles <NUM> of the plurality of degasification modules <NUM> in parallel. As a result, one degasification unit <NUM> is formed. In a case in which one degasification unit <NUM> is constituted by one degasification module <NUM> as in the degasification unit 2B shown in <FIG>, such a procedure is not necessary.

A plurality of degasification units <NUM>, a housing <NUM> which houses the plurality of degasification units <NUM> and has an inlet 3a through which the liquid is supplied from outside and an outlet 3b through which the liquid is discharged to the outside, and a suction pipe <NUM> are prepared. Next, with the housing sealing portion <NUM> which partitions the internal space of the housing <NUM> into the upstream side region B on the inlet 3a side and the downstream side region C on the outlet 3b side via the plurality of degasification units <NUM>, the plurality of the degasification units <NUM> are fixed to the housing <NUM>. Further, the suction pipe <NUM> is installed such that the suction pipe <NUM> penetrates the housing <NUM> and is connected to both ends of the degasification module <NUM> to which the inside of the hollow fiber membrane <NUM> is opened. Then, the pressure losses of the liquid of the plurality of degasification units <NUM> are made different depending on the distance from the central axis L of the housing <NUM>. Such setting of the pressure loss of the liquid can be performed by the various methods described above.

In the above, the embodiment of the present invention has been described, but the present invention is not limited to the above embodiments. For example, in the above embodiment, the configuration of the degasification unit has been specifically described, but as the degasification unit, degasification units in various configurations can be used. Further, in the above embodiment, it has been described that each degasification module includes a module inner pipe, but each degasification module may not include such a module inner pipe. In this case, for example, the hollow fiber membrane bundle (the woven fabric) of each degasification module is wound around the connection supply pipe directly.

Claim 1:
A degasification system (<NUM>) comprising:
a plurality of degasification units (<NUM>, 2A, 2B, 2C, 2D, <NUM>, 22A, 22B, 22C, 22D) configured to degasify a liquid;
a cylindrical housing (<NUM>) configured to house the plurality of degasification units (<NUM>, 2A, 2B, 2C, 2D, <NUM>, 22A, 22B, 22C, 22D) in parallel: and
a suction pipe (<NUM>) communicating with an inside of hollow fiber membranes (<NUM>) and penetrating the housing (<NUM>) to suction the inside of the hollow fiber membranes (<NUM>),
wherein each of the plurality of degasification units (<NUM>, 2A, 2B, 2C, 2D, <NUM>, 22A, 22B, 22C, 22D) includes a hollow fiber membrane bundle (<NUM>) in which the plurality of hollow fiber membranes (<NUM>) are bundled in a cylindrical shape and a cylinder (<NUM>) in which the hollow fiber membrane bundle (<NUM>) is housed,
wherein the housing (<NUM>) has an inlet (3a) through which the liquid is supplied from outside, an outlet (3b) through which the liquid is discharged to the outside, and a sealing portion (<NUM>) which partitions an internal space of the housing (<NUM>) into an upstream side region (B) on the inlet (3a) side and a downstream side region (C) on the outlet (3b) side via the plurality of degasification units (<NUM>, 2A, 2B, 2C, 2D, <NUM>, 22A, 22B, 22C, 22D),
wherein the plurality of degasification units (<NUM>, 2A, 2B, 2C, 2D, <NUM>, 22A, 22B, 22C, 22D) are arranged in parallel so that the liquid is supplied in parallel from the inlet (3a),
wherein the plurality of degasification units (<NUM>, 2A, 2B, 2C, 2D, <NUM>, 22A, 22B, 22C, 22D) are configured such that pressure losses of the liquid differ depending on a distance from a central axis (L) of the housing (<NUM>), so that a deviation of a flow rate of a liquid flowing through the plurality of degasification units (<NUM>, 2A, 2B, 2C, 2D, <NUM>, 22A, 22B, 22C, 22D) is reduced, and
wherein the pressure loss of the liquid flowing through the degasification units (<NUM>, 2A, 2B, 2C, 2D, <NUM>, 22A, 22B, 22C, 22D) increases the closer the degasification units (<NUM>, 2A, 2B, 2C, 2D, <NUM>, 22A, 22B, 22C, 22D) are to the central axis of the housing (<NUM>).