GB2604591A - Membrane contactor assembly for degassing a liquid - Google Patents

Membrane contactor assembly for degassing a liquid Download PDF

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Publication number
GB2604591A
GB2604591A GB2102947.5A GB202102947A GB2604591A GB 2604591 A GB2604591 A GB 2604591A GB 202102947 A GB202102947 A GB 202102947A GB 2604591 A GB2604591 A GB 2604591A
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GB
United Kingdom
Prior art keywords
liquid
assembly
gas
housing
vacuum
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
GB2102947.5A
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GB202102947D0 (en
Inventor
Lange Neville
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Veolia Water Solutions and Technologies Support SAS
Original Assignee
Veolia Water Solutions and Technologies Support SAS
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Veolia Water Solutions and Technologies Support SAS filed Critical Veolia Water Solutions and Technologies Support SAS
Priority to GB2102947.5A priority Critical patent/GB2604591A/en
Publication of GB202102947D0 publication Critical patent/GB202102947D0/en
Publication of GB2604591A publication Critical patent/GB2604591A/en
Pending legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D19/00—Degasification of liquids
    • B01D19/0031—Degasification of liquids by filtration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D63/00—Apparatus in general for separation processes using semi-permeable membranes
    • B01D63/02—Hollow fibre modules
    • B01D63/04—Hollow fibre modules comprising multiple hollow fibre assemblies
    • B01D63/043—Hollow fibre modules comprising multiple hollow fibre assemblies with separate tube sheets
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D63/00—Apparatus in general for separation processes using semi-permeable membranes
    • B01D63/02—Hollow fibre modules
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2313/00—Details relating to membrane modules or apparatus
    • B01D2313/10—Specific supply elements
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2313/00—Details relating to membrane modules or apparatus
    • B01D2313/13—Specific connectors
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2315/00—Details relating to the membrane module operation
    • B01D2315/22—Membrane contactor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2319/00—Membrane assemblies within one housing
    • B01D2319/04—Elements in parallel

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Degasification And Air Bubble Elimination (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)

Abstract

A membrane contactor assembly 20 is provided for degassing a liquid, such as water. The assembly 20 comprises a housing having open top and bottom ends, and a hollow fibre structure 4 disposed within the housing. The top end of the housing is adapted to receive gas or vacuum for degassing a liquid. The bottom end of the housing is adapted to receive gas or vacuum for degassing a liquid. At least one intermediate opening in the housing is intermediate the top and bottom ends and adapted to communicate gas or vacuum for degassing a liquid to the hollow fibre structure 4. Also disclosed is a further invention directed to a membrane contactor assembly for degassing a liquid, characterised by a liquid transfer pipe for supplying liquid to the assembly, the liquid transfer pipe sealed to the housing such that gas or vacuum communicated to the housing is prevented from entering the liquid transfer pipe. The membrane assembly may remove a gas, such as oxygen from the liquid.

Description

Membrane Contactor Assembly for Degassing a Liquid
Technical Field
The subject disclosure relates generally to membrane contactors or modules for degassing a liquid such as deaeration of water, and in particular to a membrane contactor or module assembly for degassing a liquid.
Background
In the oil and gas industry, water may be used for injection into a subterranean reservoir for increasing or enhancing recovery of oil and gas from the reservoir. It is often preferable to remove oxygen from the water as oxygen in the water may detrimentally enhance the corrosiveness of water.
Deaeration or degassing of water or other fluids may be achieved through a number of systems including a deaeration tower, which uses vacuum deaeration. The deaeration tower is filed with mass transfer packing and water is distributed over the surface of the packing. The pressure within the vapour space of the tower is reduced to near the vapour pressure of the water as the water trickles down through the packing, which causes gases dissolved in the water to evolve from the water. The concentration of the gas in the water approaches equilibrium with the partial pressure of the gas in the vapour space of the tower according to Henry's Law. This form of vacuum deaeration will remove all gases from the water including, for example, Nitrogen, in addition to oxygen.
The vacuum in a vapour space of the deaeration tower may be replaced with a gas, which contains little or no oxygen to reduce the partial pressure of oxygen to remove only the oxygen from the water. This process is generally referred to as gas stripping.
For example there is the "Minox" process which uses Nitrogen as the stripping gas.
Alternatively, the stripping gas may be the gas produced from an oil reservoir, which naturally contains no oxygen.
Membrane contactors or modules may be used to effect water deaeration, degassing or deoxygenafion. A membrane contactor or module typically includes a bundle of microporous hollow fibres and a housing within which the fibres are located. The housing is provided with four (4) fluid ports, an inlet for water to be treated, an outlet for treated water, an inlet for a vacuum or gas, and an outlet for the extracted vacuum or gas. The hollow fibres are arranged end to end in the housing and potted on opposite ends of the housing with the fibre bores opening out into each of the end faces of the housing. End caps may be secured at either end of the housing for securing the membrane contactor or modules to other elements.
In general water to be treated passes over one side (the outside) of the fibres, while a vacuum or gas which contains no or very little oxygen passes over the other side (the inside or "lumen") of the fibres. The gas or vacuum for deaeration may be designated the "Iumen-side" fluid because it is the fluid which passes through the internal lumens of the hollow fibres. Water enters and exists the housing through the inlet and outlet. The water is designated the "shell-side" fluid as it contacts the external surfaces of the hollow fibres. The shell-side fluid, i.e. water, flows through the interstices between fibres of the bundle, and may be directed to flow parallel or perpendicular to the fibre length.
While membrane contractors are suitable for deaeration the flow rate through these contactors may be lower than those required for many industrial applications. For example, the approximate maximum flow rate of the 3MTm Liquid-CeITM EXF-8x80 series membrane contactor is 28.4 m3/hour and the maximum flow rate of the DuPont' LigasepTM Model LDM-120-HS/LS membrane module is 50 ms/hour. Flow rates in industrial applications, such as the oil and gas industry may be required to be greater than 1600 m3/h. To reach this required flow rate many membrane contactors or modules would need to be connected together in parallel. However, this arrangement would have many joints, which may leak. Further, such an arrangement would occupy a large area and the interconnection piping to supply/extract fluids from the membrane contactors or modules, and the contactors or modules themselves would require significant supporting structure.
This background serves only to set a scene to allow a person skilled in the art to better appreciate the following description. Therefore, none of the above discussion should necessarily be taken as an acknowledgement that that discussion is part of the state of the art or is common general knowledge. One or more aspects/embodiments of the disclosure may or may not address one or more of the background issues.
Summary
Accordingly, in an aspect there is provided a membrane contactor or module assembly for degassing a liquid.
The membrane contactor or module assembly may provide for higher flow rates than are possible with conventional membrane contactors. Accordingly, the membrane contactors may provide a degassing system which may be used across a broader range of applications.
The assembly may comprise a housing having open top and bottom ends, and a hollow fibre structure disposed within the housing, the top end of the housing adapted to receive gas or vacuum for degassing a liquid, the bottom end of the housing adapted to receive gas or vacuum for degassing a liquid, and at least one intermediate opening in the housing intermediate the top and bottom ends adapted to communicate gas or vacuum for degassing a liquid to the hollow fibre structure.
The provision of gas or vacuum at the top and bottom ends of the assembly provides gas or vacuum to draw gas such as oxygen, from a liquid to be degassed. The additional intermediate opening in the housing intermediate the ends ensures that the pressure of the gas or vacuum provided is uniform across the assembly.
An assembly which lacks such an intermediate opening would experience pressure drop of evolved gasses flowing along bores of fibres within the hollow fibre structure.
This would result in significantly uneven pressure along the length of the hollow fibre structure, i.e. lower pressure adjacent the ends and highest pressure at a midpoint of the hollow fibre structure. This would result in poor gas, e.g. oxygen, removal.
Accordingly, the provision of an intermediate opening improves gas removal from the liquid over conventional membrane contactors while providing higher flowrates than those available membrane contactors.
The intermediate opening provides an access point through which gas or vacuum may be provided to the hollow membrane structure.
The intermediate opening may be located between two hollow fibre structures within the housing such that gas or vacuum for degassing a liquid is communicable to one or more of the two hollow fibre structures.
The intermediate opening may provide gas or vacuum communication to an uppermost hollow fibre structure. The gas or vacuum may additionally draw out liquid which has leaked into the bores of fibres of the hollow fibre structure. This may ensure gas withdrawal from a liquid is not detrimentally affected by liquid within the bores of the hollow fibre structure.
The intermediate opening may form a chamber within the housing. The chamber may be an annular chamber. The chamber may provide for communication of gas or vacuum to bores of fibres of the hollow fibre structure for degassing a liquid.
The chamber may be defined between hollow fibre structures disposed within the housing.
The hollow fibre structure may comprise hollow fibres. The hollow fibres may be arranged in one or more bundles. The hollow fibres may be arranged end to end within the housing. The hollow fibres may be potted on opposite ends of the housing. The potting may be resin. Bores of the fibres may open out into each of the end faces of the housing.
Liquid to be treated may pass over one side (the outside) of the fibres, while a vacuum or gas which contains no or very little oxygen may pass over the other side (the inside or "lumen") of the fibres. The gas or vacuum for deaerafion or degassing may be designated the "lumen-side" fluid because it is the fluid which passes through the internal lumens of the hollow fibres. The liquid may be designated the "shell-side" fluid as it contacts the external surfaces of the hollow fibres. The shell-side liquid, e.g. water, may flow through interstices between hollow fibres, and may be directed to flow parallel or perpendicular to the fibre length.
In some applications the liquid may flow through the lumens and the gas may be on the outside of the fibre and in other applications both the lumen side fluid and shell side fluid may be liquid or they may be gaseous.
The liquid may be degassed within the housing such that liquid to be degassed enters the housing, is degassed within the housing and then degassed liquid exits the housing.
The assembly may further comprise a liquid runoff assembly or liquid diverter within the chamber for preventing liquid from one hollow fibre structure from entering another hollow fibre structure.
Liquid flowing from the bore, i.e. the lumen side, of one hollow fibre structure to another hollow fibre structure may negatively impact or influence degassing of a liquid. Liquid may flow through hollow fibres of the hollow fibre structure and then flow to another hollow fibre structure. Liquid from one hollow fibre structure may flow into bores of another hollow fibre structure, in particular a lower hollow fibre structure. Liquid within the bores of hollow fibre structure, i.e. within the bores of the hollow fibres of the hollow fibre structure, may impair the collection of gas, e.g. oxygen, to or from the bores of the fibres. This may negatively affect performance of the assembly.
The liquid runoff assembly may prevent liquid from passing from one hollow fibre structure to another structure, e.g. a lower hollow fibre structure. The liquid may be prevented from collecting on the top of a hollow fibre structure, in particular on top of potting into which fibre of the hollow fibre structure is potted. This ensures liquid does not impair collection of gas to or from the bores of fibres within the hollow fibre structure.
The liquid runoff assembly may comprise a structure adapted to direct fluid from a hollow fibre structure to a gas or vacuum source.
The liquid runoff assembly may comprise a runoff membrane adapted to restrict flow of liquid while allowing flow of gas. The runoff membrane may be adapted to ensure gas or vacuum pressure is not negatively affected.
The liquid runoff assembly may comprise a labyrinth structure. The labyrinth structure may define a series of regular or irregular liquid flow paths within the chamber.
The liquid runoff assembly may direct liquid from a hollow fibre structure to a gas or vacuum source, or gas transfer tubing such that liquid does not flow to another hollow fibre structure.
The structure may form a declined surface relative to a flow path of liquid from a hollow fibre structure of the assembly to direct liquid to a gas or vacuum source. The declined surface may be adapted to direct liquid to a gas or vacuum source, or gas transfer tubing via gravity.
The structure may form two surfaces which overlap relative to the flow path. The overlapping surface may define a serpentine flow path.
The overlapping surfaces may be formed by opposing lips projecting from sidewalls of the chamber. The sidewalls may be lateral sidewalls of the chamber.
The opposing lips may project at supplementary angles. The angles are defined relative to a common direction, e.g. the longitudinal axis of the membrane contactor assembly. Supplementary angles are defined herein to mean angles which when added together sum to 180 degrees.
The opposing lips may define a serpentine flow path.
One of the lips may project downwardly relative to the lateral axis of the assembly and another of the lips may project upwardly relative to the lateral axis of the assembly. A lateral axis of the assembly may be defined as being perpendicular to the longitudinal axis of the assembly which runs between the top and bottom ends.
The chamber may be connectable to gas transfer tubing to supply a gas or vacuum. The gas transfer tubing may run parallel to the assembly.
The hollow fibre structure may comprise a bundle of hollow fibres.
The hollow fibres may be hydrophilic.
The assembly may comprise end caps affixed to each open end of the housing. The end caps may be cylindrical.
The hollow fibre structure may be integrally potted in the housing.
The housing may be cylindrical.
The housing may be formed from an inner and outer tube forming an annulus therebetween The hollow fibre structure may be disposed within the annulus formed between the inner and outer tubes.
The inner and outer tubes may be perforated. Liquid to be degassed may flow from a central bore defined by the inner tube through perforations in the inner tube, into the annulus defined between the inner and outer tubes, and then out of perforations in the outer tube into a volume surrounding the outer tube.
The liquid may be degassed such that liquid which flows out of perforations in the outer tube is degassed, e.g. has oxygen removed or substantially removed therefrom, and may be used in industrial applications, such as in oil and gas discovery, production, completion, etc. Liquid may be degassed within the housing. Vacuum or gas may be supplied or extracted via the top end, bottom end, and/or intermediate opening while liquid is in the housing. The vacuum or gas may reduce the partial pressure of the gases within the bore of the fibres so that they can extract gases from the liquid. The close contact of the liquid with the gas or vacuum through the wall of the hollow fibres allows the gases dissolved in the liquid to approach equilibrium with the partial pressure of the gas in the bore of the fibre in accordance with Henry's law. If a gas within the bore of the fibres is at a partial pressure higher than the equilibrium partial pressure of that same gas dissolved in the fluid, then the gas in the bore of the fibre will pass through the fibre and dissolve into the liquid. The liquid may be a combination of liquid and gas.
The perforations in the inner and outer tubes may be used to control distribution of liquid. The sizes and shapes of the perforations may be varied such that they are nonuniform, or they may be uniform.
The assembly may further comprise a perforated central tube positioned within the central bore defined by the inner tube, liquid to be degassed entering the annulus via the central tube The perforations in the central may be used to control the distribution of liquid to the contactors in the assembly. The sizes and shapes of the perforations may be varied such that they are non-uniform, or they may be uniform.
The assembly may be formed by a single membrane contactor or module for degassing a liquid. The membrane contactor may comprise a housing having open ends and a hollow fibre structure disposed within the housing. The housing of the assembly may be defined by the housing of the membrane contactor. The intermediate opening is located intermediate the open ends of the housing of the membrane contactor.
The assembly may comprise at least two stacked membrane contactors or modules for degassing a liquid. Each membrane contactor or module may comprise a housing having open ends and a hollow fibre structure disposed within the housing. The housing of the assembly is defined by the housings of the membrane contactors. The intermediate opening is located between adjacent stacked membrane contactors.
The housing of each membrane contactor or module may be formed by two hollow tubes, an inner tube and an outer tube. The inner tube may be placed within the outer tube such that an annulus is formed therebetween. The inner tube may be perforated to allow liquid to be degassed to enter the annulus. The outer tube may be perforated to allow liquid which has been degassed to exit the annulus. The hollow fibre structure may be positioned within the annulus between the tubes. The hollow fibre structure may positioned end to end within the annulus. The hollow fibre structure may be potted at the ends of the fibres. The hollow fibre structure may comprise hollow fibres. The hollow fibres may run parallel to the length of the tubes, i.e. longitudinally. The bores of the hollow fibres may be exposed at the ends of the housing.
Each membrane contactor may comprise end caps affixed to each open end of the housing of the membrane contactor.
The hollow fibre structure may be integrally potted in the housing.
The assembly may further comprise a lowermost connector adapted to form a socket for connection to a liquid transfer pipe for supplying liquid to be degassed. The socket may be for connection to a gas plenum for supplying vacuum or gas to the assembly.
The assembly may further comprise a liquid transfer pipe fluidly connected to the socket. The liquid transfer pipe may supply liquid to be degassed.
The assembly may further comprise a plug connectable to an uppermost connector of the assembly. The plug may provide a sealing function.
The top end of the housing may be connectable to gas transfer tubing to supply a gas or vacuum The bottom end of the housing may be connectable to gas transfer tubing to supply a gas or vacuum.
A liquid to be degassed may be water.
A gas to be removed from the liquid may be oxygen.
The assembly may comprise three intermediate openings. The number of intermediate openings may be varied to achieve a desire flow rate of the membrane contactor assembly.
The intermediate opening may be provided within a connector for fluidly connecting membrane contactors.
In another aspect there is provided a connector for fluid connection to at least one membrane contactor for degassing a liquid, the membrane contactor comprising a housing having open ends, and at least one hollow fibre disposed in the housing, the connector connectable to a membrane contactor The connector may comprise or define: a structure defining a chamber for communicating gas or vacuum with an interior space of a hollow fibre of a membrane contactor via a passage in the structure, the passage connectable to a gas or vacuum source.
The hollow fibre may be integrally potted within the housing.
The connector may be adapted for fluidly connecting two membrane contactors.
The chamber may be adapted for communicating gas or vacuum with interior space of hollow fibres of the two membrane contactors.
The structure may be adapted to direct liquid from a hollow fibre of a membrane contractor to the passage.
The structure may form a declined surface relative to a flow path of liquid from a hollow fibre of a membrane contractor to direct liquid to the passage.
The structure may form two surfaces which overlap relative to the flow path of liquid.
The overlapping surfaces may be formed by opposing lips projecting from sidewalls of the connector.
The opposing lips may project at supplementary angles.
The opposing lips may define a serpentine flow path.
One of the lips may project downwardly relative to the lateral axis of the connector and another of the lips may project upwardly relative to the lateral axis of the connector.
The passage may be connectable to gas transfer tubing.
The connector may comprise the described liquid runoff assembly or liquid diverter.
In another aspect there is provided a column of membrane contactors for degassing liquid.
The column may comprise: at least two membrane contactors, each membrane contactor comprising a housing having open ends and an hollow fibre disposed in the housing; and a connector for fluidly connecting two membrane contactors or modules, the connector connectable to end faces of two membrane contactors, the connector comprising a structure defining a chamber for communicating gas or vacuum with an interior space of hollow fibres of the two membrane contactors via a passage in the structure, the passage connectable to a gas or vacuum source.
The connector may form an intermediate connector.
The membrane contactors may be stacked vertically end to end or may be arranged horizontally. The membrane contactors may be arranged with end faces of adjacent contactors facing each other.
The column may comprise the described liquid runoff assembly or liquid diverter. The liquid runoff assembly may be positioned between the membrane contactors. The liquid runoff assembly may form part of the connector.
The hollow fibre may be potted within the housing of membrane contactor.
The passage may be connectable to gas transfer tubing.
The column may further comprise: an upper connector for fluid connection to one of the two membrane contactors, the upper connector connectable to the membrane contactor. The membrane contactor may be an upper or top membrane contactor. The upper connector may be connectable to an end face of the membrane contactor not connected to the connector.
The upper connector may comprise: a structure defining a chamber for communicating gas or vacuum with an interior space of a hollow fibre of a membrane contactor via a passage in the structure, the passage connectable to a gas or vacuum source.
The passage of the upper connector may be connectable to gas transfer tubing.
The column may further comprise: a lower connector for fluid connection to the other of the two membrane contactors, the lower connector connectable to the other membrane contactor. The membrane contactor may be an lower or bottom membrane contactor. The lower connector may be connectable to an end face of the membrane contactor not connected to the connector.
The lower connector may comprise: a structure defining a chamber for communicating gas or vacuum with an interior space of a hollow fibre of a membrane contactor via a passage in the structure, the passage connectable to a gas or vacuum source.
The passage of the lower connector may be connectable to gas transfer tubing.
Multiple passages may be present in the lower connector. Particular passages may be connectable to gas transfer tubing. Certain passages may be connectable to a gas or vacuum inlet.
The lower connector may be fluidly connectable to a liquid transfer pipe for supplying liquid to be degassed.
The housing of each membrane contactor may be formed from an inner and outer tube forming an annulus therebetween.
The hollow fibre may be disposed within the annulus formed between the inner and outer tubes.
The tubes may be perforated such that liquid to be degassed flows within a central bore defined by the inner tube, through perforations in the inner tube, into the annulus formed between the tubes, through perforations in the outer tube and into a volume surrounding the outer tube. The liquid may be degassed in the annulus such that liquid which exits the outer tube into the volume may be degassed liquid.
The column may further comprise: a perforated central tube positioned within the central bore defined by the inner tube, liquid to be degassed entering the column via the central tube.
The perforations in the tube may be used to control the distribution of liquid to the contactors within the column. The sizes and shapes of the perforations may be varied such that they are non-uniform, or they may be uniform.
The described plug may plug the central tube A lowermost connector of the column may form a connection member for connection to a liquid transfer pipe for supplying liquid to be degassed. The connection member may comprise a socket.
The column may further comprise: the liquid transfer pipe fluidly connected to the spigot, the liquid transfer pipe for supplying liquid to be degassed.
The column may further comprise: a plug connectable to an uppermost connector of the column.
In another aspect there is provided an apparatus for degassing a liquid. The apparatus may allow for multiple assemblies or columns to be located within the apparatus which may increase possible flow rates of degassed fluids which may be provided. The increased flow rates available from the apparatus may allow for a wide range of applications, including applications within the oil and gas industry.
The assemblies may be located vertically within the vessel or horizontally within the vessel, or some combination of both.
The apparatus may comprise: a vessel; a partition plate dividing the vessel into first and second chambers; and at least one of the described assembly or column located within the second chamber.
The apparatus may comprise a single or multiple assemblies.
The assembly or column located within the second chamber may have no intermediate opening. As such, the assembly may comprise a housing having open and bottom ends, and a hollow fibre structure disposed within the housing. Both of the ends may be adapted to receive gas or vacuum for degassing a liquid. Furthermore, the apparatus may comprise a combination of both types of assemblies, namely one or more assemblies with one or more intermediate openings and one or more assemblies without any intermediate openings.
The apparatus may facilitate liquid runoff from within the bores of the hollow fibre structure in the assembly, or within individual membrane contactor or modules. Such an apparatus may ensure degassing is not negatively impacted by liquid within the bores.
The apparatus may further comprise: a gas transfer plate located within the first chamber, the gas transfer plate and the partition plate defining a gas plenum therebetween for supplying vacuum or gas to the assembly or column for degassing a liquid.
Liquid runoff from within the bores may be collect via gas transfer tubing fluidly connected to the assembly or column. The liquid may collect in the gas plenum. Vacuum or gas supplied via the gas plenum may be supplied by a gas transfer tubing fluidly connected to the gas plenum. The gas transfer tubing may also provide a flow path for liquid runoff. Alternatively or additionally a separate liquid runoff port tube or pipe fluidly communicating to the gas plenum may be provided.
The vessel may be oriented such that liquid runoff from within the bore runs through the gas transfer tubing fluidly connected to the assembly and into the gas plenum through the force of gravity. Additionally the gas transfer tubing connected to the gas plenum may draw liquid from the gas plenum through the force of gravity.
The apparatus may further comprise: at least one liquid transfer pipe for supplying liquid to be degassed to the vessel.
The liquid transfer pipe may provide a flow path for liquid from the first chamber into the assembly within the second chamber. As will be appreciated a liquid transfer pipe may be present for each assembly within the second chamber of the apparatus. Multiple assemblies may be present within the second chamber.
The liquid transfer pipe may be adapted to sealingly engage a central bore of the assembly. A seal between the liquid transfer pipe and the central bore of the assembly may ensure that liquid entering the assembly does not enter the gas transfer tubing and affect degassing of the liquid.
The liquid transfer pipe may be positioned within an aperture in the partition plate. The liquid transfer pipe may be positioned within an aperture in the partition plate such that a clearance is present between the sidewalls of the aperture formed in the partition plate and the liquid transfer pipe. Multiple apertures may be present in the partition plate to accommodate multiple liquid transfer tubes.
The liquid transfer pipe may be positioned within an aperture in the gas transfer plate.
Multiple apertures may be present in the gas transfer plate to accommodate multiple liquid transfer tubes.
The aperture in the gas transfer plate may define a smaller width than the aperture in the partition plate. Clearance between the partition plate and the liquid transfer pipe may allow for angulafion of the liquid transfer pipe. The liquid transfer pipe opening in the gas transfer plate may be non-concentric with the opening formed at the central bore of the assembly proximate the liquid transfer pipe.
The liquid transfer pipe may be sealed relative to sidewalls of the aperture in the gas transfer plate.
The liquid transfer pipe may be sealed relative to sidewalls of the aperture in the gas transfer plate such that angulation of the liquid transfer pipe relative the assembly is permitted.
The liquid transfer pipe may be sealed with an 0-ring. One of skill in the art will appreciate that other sealing means may be used.
The 0-ring may be positioned in a ring groove in the liquid transfer pipe.
The 0-ring lands parallel the 0-ring groove in the liquid transfer pipe may partially form a spherical surface. In other words the 0-ring lands may be angled relative to the ring groove to form curved surfaces relative to the sidewalls of the aperture in the gas transfer plate. The ring lands may have conical surfaces.
The described gas transfer plate may allow for angulation of the gas transfer tubing within the aperture in the gas transfer plate without jamming of the gas transfer tubing within the aperture.
Allowing for angulation of the liquid transfer pipe may accommodate manufacturing tolerances, e.g. lateral offset of the liquid transfer pipe and the central bore of the assembly. This may reduce manufacturing costs and manufacturing time.
In another aspect there is provided a method of degassing a liquid. The method may provide higher flow rate of degassed liquid than previously-known degassing methods.
Such a method may have a broader range of applications than known degassing methods.
The method may comprise: drawing a liquid to be degassing through into a central bore of a housing of a membrane contactor assembly, the housing having open top and bottom ends, the membrane contactor assembly further comprising a hollow fibre structure disposed within the housing; the top end of the housing adapted to receive gas or vacuum for degassing a liquid; the bottom end of the housing adapted to receive gas or vacuum for degassing a liquid; and at least one intermediate opening in the housing intermediate the top and bottom ends adapted to communicate gas or vacuum for degassing a liquid to the hollow fibre structure; drawing a liquid to be degassed through perforations in the housing such that liquid passes over the hollow fibre structure; and passing a gas or vacuum through an interior space of the hollow fibre structure via the top end, bottom and intermediate opening to degas a liquid.
In another aspect there is provided a method of manufacturing an apparatus for degassing a liquid.
The method may comprise: assembling a gas transfer plate and a partition plate to define a gas plenum; and positioning the membrane contactor assembly on the partition plate.
Assembling the gas transfer plate and the partition plate may comprise providing one or more spacers between the plates to define the gas plenum.
The method may further comprise: locating the assembly within an opening or aperture of the partition plate.
The method may further comprise: fitting a guide plate to an upper end of the assembly opposite the partition plate.
In another aspect there is provided a membrane contactor assembly for degassing a liquid.
The assembly may allow for connection to a liquid source to supply liquid to be degassed, and to vacuum or gas for degassing. The assembly may provide for connections was reduce manufacturing time and costs. The assembly may allow for the provision of multiple assemblies in a single vessel thereby providing increasing flow rates of degassed liquid.
The assembly may comprise a housing having open top and bottom ends, and a hollow fibre structure disposed within the housing, the top end of the housing adapted to receive gas or vacuum for degassing a liquid, and the bottom end of the housing adapted to receive gas or vacuum for degassing a liquid.
The assembly may further comprise: a liquid transfer pipe for supplying liquid to the assembly. The liquid transfer pipe may be sealed to the housing such that gas or vacuum communicated to the housing is prevented from entering the liquid transfer pipe.
Gas or vacuum supplied to the housing may be suppling from a gas plenum.
The gas plenum may surround the liquid transfer pipe.
The assembly may comprise one or more of the features described in respect of a previously-described assembly or column.
In another aspect an apparatus for degassing a liquid is provided. The apparatus may allow for multiple assemblies or columns to be located within the apparatus which may increase possible flow rates of degassed fluids which may be provided. The increased flow rates available from the apparatus may allow for a wide range of applications, including applications within the oil and gas industry.
The apparatus may comprise: a vessel, a partition plate dividing the vessel into first and second chambers; and at least one of the described assemblies located within the second chamber.
The apparatus may further comprise: a gas transfer plate located within the first chamber, the gas transfer plate and the partition plate defining a gas plenum therebetween for supplying vacuum or gas to the assembly for degassing a liquid.
The liquid transfer pipe may be positioned within an aperture in the partition plate.
The gas plenum may surround the liquid transfer pipe.
The apparatus may comprise one or more of the features described in respect of a previously-described apparatus.
While the term liquid has been used to refer to the liquid to be degassed, or liquid so degassed, one of skill in the art will appreciate that gas may be present in the liquid. However, the degassing process may remove at least a portion of the gas within the liquid leaving a greater percentage of liquid and/or a lower percentage of gas.
While particular features and elements have been described in relation to the assembly, apparatus, connector, column or methods, one of skill in the art will appreciate that such features or elements may be applied to any of the other assembly, apparatus, connector, column or methods.
The described assembly, apparatus, connector, column and methods may provide one or more of the benefits described in respect of the assembly, apparatus, connector and methods, and vice versa.
Brief Description of the Drawings
A description is now given, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is an elevation view of a membrane contactor; Figure 2 is a plan view of the membrane contactor of Figure 1; Figure 3 is a cross sectional elevation view of the membrane contactor of Figure 1; Figure 4 is an elevation view of a membrane contactor assembly; Figure 5 is a plan view of the membrane contactor assembly of Figure 1; Figure 6 is an enlarged cross sectional elevation view of an upper end of the membrane contactor assembly of Figure 4; Figure 7 is an enlarged cross sectional elevation view of an intermediate portion of the membrane contactor assembly of Figure 4; Figure 8 is an enlarged cross sectional elevation view of a lower end of the membrane contactor assembly of Figure 4; Figure 9 is an enlarged cross sectional elevation view of a lower end of the membrane contactor assembly with non-concentric apertures of Figure 4; Figure 10 is an enlarged cross sectional elevation view of a lowermost portion of a liquid transfer pipe of the membrane contactor assembly of Figure 4; Figure 11 is a cross sectional elevation view of an apparatus for degassing a liquid; and Figure 12 is a cross sectional plan view the apparatus of Figure 11.
Detailed description
A membrane contactor or module generally identified by reference numeral 1 is shown in Figures 1 to 3. The membrane contactor or module 1 is for use in degassing a liquid. The membrane contactor 1 comprises an inner tube 3 and an outer tube 2 surrounding the inner tube 3. The inner and outer tubes 3, 2 define an annulus therebetween. The tubes 2, 3 are generally cylindrical.
Each of the tubes 2, 3 are perforated. In particular, the inner tube 3 has holes 9 and the outer tube 2 has holes 8. Liquid may flow from within the central bore defined by the inner tube 3 through holes 9 in the inner tube 3 and into the annulus between the tubes 2, 3, and out of holes in the holes 8 in the outer tube 2 into a volume surrounding the outer tube 2.
As depicted in Figure 3, a hollow fibre structure 4 is contained or positioned within the annulus formed between the tubes 2, 3. The hollow fibre structure 4 comprises hollow fibres running parallel to the longitudinal axis of the tubes 2, 3. In this example, the hollow fibres are hydrophilic although this may not be the case. The hollow fibres are potted in resin in potting 5 within the annulus defined by the tubes 2,3 of the membrane contactor 1. The potting 5 may be resin. The potting 5 commences at line 7 indicated in Figure 3. The hollow fibres pass through the potting 5 to external end faces 6 of the membrane contactor 1 such that bores of the hollow fibres are accessible to gas or vacuum communicated at the end faces 6. The potting 5 is adapted to not block or restrict access to the bore of the hollow fibres.
While not shown in Figures 1-3 end caps may be secured to the end faces 6 of the membrane contactor or module 1. The ends caps may be used to secure the contactor or module 1 to other elements. The end caps may take the form of connectors as will be described.
The outer tube 2 further comprises sealing members at either longitudinal end of the outer tube 2 for sealing the outer tube 2 to a gas or vacuum supply such that gas or vacuum may be supplied to the hollow interior of the fibres of the structure 4. In this example, the sealing members are 0-ring adapted to fit in 0-ring groves 11 on either end of the outer tube 2. Additional sealing members may be used to seal surface 10 as will be described.
In use, liquid to be degassed enters or is driven into the central bore of the inner tube 3 and passes through holes 9 into the annulus between tubes 2, 3. Liquid may be driven through central tubing or piping or directly into the central bore. The liquid is degassed while passing over the fibres of the structure 4 within the annulus. The liquid then flows over the exterior surfaces of the hollow fibres of the fibre structure 4, and then out through holes 8 of the outer tube 2 to a space exterior the outer tube 2. While liquid is flowing in this manner, vacuum or gas is supplied or extracted at the end faces 6 of the membrane contactor 1 to or from the bores of the hollow fibres to reduce the partial pressure of the gases within the bore of the fibres so that they can extract gases from the liquid. The close contact of the fluid with the gas or vacuum through the wall of the hollow fibres allows the gases dissolved in the fluid to approach equilibrium with the partial pressure of the gas in the bore of the fibre in accordance with Henry's law. If a gas within the bore of the fibres is at a partial pressure higher than the equilibrium partial pressure of that same gas dissolved in the fluid, then the gas in the bore of the fibre will pass through the fibre and dissolve into the water which could occur when using gas stripping rather than vacuum. The sizes and patterns of the holes 8, 9 in the tubes 2, 3 may be varied to change the distribution of fluid along the length of the fibres within the annulus. For example, the holes sizes and patterns may be varied to achieve a uniform flow velocity of the fluid passing over the fibres at all positions along the length of the fibres.
The liquid being degassed may be water. The gas being removed from the liquid may be oxygen A number of membrane contactors or modules 1 may be assembled into a column or assembly. A membrane contactor assembly generally identified by reference numeral 20 is shown in Figures 3 and 4. The assembly 20 is generally cylindrical and comprises multiple membrane contactors 1. The membrane contactors 1 are stacked and interconnected to increase the flow rate of the assembly 20 over that of an individual membrane contactor 1 as will be described. In this example, four membrane contactors 1 are present, but one of skill in the art will appreciate that more or fewer membrane contactors may be present. Furthermore, the assembly 20 may comprise a single membrane contactor or module 1 with multiple access points or intermediate openings within the contactor 1 to allow for the provision of gas or vacuum and liquid runoff or diversion.
The membrane contactors 1 are connected to gas or vacuum by gas transfer tubing 27 which spans the length of the stack of membrane contactors 1 and runs parallel to the stack. The gas transfer tubing 27 is generally cylindrical. The gas transfer tubing 27 is connected to a top end of the assembly 20 by a top connector 23. The gas transfer tubing 27 is connected to a bottom end of the assembly by a bottom connector 21. In this manner gas or vacuum is provided to the stack of membrane contactors 1. The gas transfer tubing 27 is additionally connected at points intermediate the top and bottom ends. In particular, the gas transfer tubing 27 is connected between adjacent stacked membrane contactors.
The additional intermediate connections in the assembly 20 intermediate the ends ensures that the pressure of the gas or vacuum provided is uniform across the assembly 20. The improved distribution of gas or vacuum ensures flow rates can be increased without a drop off in degassing performance.
The assembly 20 further comprises a upper coupling 35 to fluidly connect the gas transfer tubing 27 to a top connector 23 connected to the top or upper most membrane contactor 1. The top coupling 35 and top connector 23 provide vacuum or gas to the top end of the assembly 20 as will be described with reference to Figure 5.
The assembly 20 further comprises a lower coupling 64 to fluidly connect the gas transfer tubing 27 to a lower connector 21 connected to the lower or bottom most membrane contactor 1. The lower coupling 64 and lower connector 21 provide vacuum or gas to the assembly 20 as will be described with reference to Figure 7. Specifically the lower connector 21 is supplied with vacuum or gas which is provided to the lower most contactor 1 of the assembly 20, and the lower coupling is provided with vacuum or gas which is provided to other contactors 1 in the assembly 20.
The assembly 20 further comprises an intermediate coupling 40 to fluidly connect the gas transfer tubing 27 to an intermediate connector 22 connected to an intermediate point of the assembly 20, in particular the junction between adjacent membrane contactors 1. The intermediate coupling 40 and intermediate connector 22 provide vacuum or gas to an intermediate point of the assembly 20 as will be described with reference to Figure 6. As shown in Figure 4, multiple intermediate couplings 40 and connectors 22 are present. In the described example, three intermediate coupling 40 and connectors 22 are present, but one of skill in the art will appreciate more or fewer may be present.
The top connector 23 forms a top or upper end cap of the assembly 20 and the bottom connector 21 forms a bottom or lower end cap of the assembly 20.
The assembly 20 additionally comprises a nut 24 secured to a thread 25 of a plug 26.
The nut 24 is tightened to the thread 25 to secure the membrane contactors 1 of the assembly 20. The thread 25 is formed on an outer surface of the plug 26. The plug 26 is generally cylindrical and prevents fluid from a central bore of the assembly 20 from existing the assembly via the top most portion of the assembly 20. The plug 26 is collinear with the membrane contactors 1 of the assembly 20.
The assembly 20 further comprises a spigot 28 projecting from the bottom connector 21 of the assembly 20. The spigot 28 may be integral with the bottom connector 21. The spigot 28 provides fluid communication for vacuum or gas for degassing a liquid as will be described. The spigot 28 is generally cylindrical. A sealing member which in this example is an 0-ring 29 is secured within a ring groove of the spigot 28 to sealingly secure the spigot 28 as will be described. The assembly further comprises a liquid transfer pipe 50 projecting from the bottom connector 21. The liquid transfer pipe 50 is generally cylindrical. The liquid transfer pipe 50 is for communicating liquid to be degassed to the membrane contactors 1 of the assembly 20. The liquid transfer pipe is generally co-linear with the spigot 28. The liquid transfer pipe 50 has a smaller diameter than the spigot 28 and projects from the spigot 28. A sealing member which in this example is an 0-ring 51 is secured within a ring groove of the liquid transfer pipe 50 to sealingly secure the pipe 50 as will be described.
An upper end or top end of the assembly 20 is shown in Figure 6. A central transfer tube 90 is located within the central bore of the inner tube 3 of the top most membrane contactor 1. The central transfer tube 90 may be perforated such that liquid to be degassed passes through holes 92 in the central transfer tube 90 into holes 9 in the inner tube 3 to be degassed as previously described. The top connector 23 fluidly connects the end face 6 of the membrane contactor 1 to the top coupling 35 which is connected to gas transfer tubing 27. The top connector 23 is fluidly connected to the end face 6 via sealing members which in this example are 0-rings 31 and 32. The central transfer tube 90 may be formed from PVC (polyvinyl chloride). While a central transfer tube 90 is described one of skill in the art will appreciate that the central transfer tube 90 need not be present. In another example the central transfer tube 90 takes the form of a solid rod. The solid rod may provide tension to hold the assembly 20 together.
The top connector 23 is generally disc shaped and matches the general shape and configuration of the membrane contactors 1. A chamber 33 is formed within the top connector 23 proximate the end faces 6. In this example, the chamber 33 is machined into the top connector 23. The chamber 33 is annular. The chamber 33 communicates with the bores of the hollow fibres of the hollow fibre structure 4 within the membrane contactor 1. A passage 34 is formed within the top connector 23. The passage 34 in the top connector 23 provides a fluid connection from the bores of the hollow fibres to the top coupling 35 via the chamber 33. The top coupling 35 is connected to gas transfer tubing 27 and the top connector 23. A passage 36 is formed within the top coupling 35 to provide a fluid communication path for vacuum or gas supplied via the gas transfer tubing 27. Thus, vacuum or gas provided via the gas transfer tubing 27 may extract or draw gas from the liquid which flows from the central transfer tube 90 into the membrane contactor 1.
The gas transfer tubing 27 is received within a socket 98a of the top coupling 35. The top coupling 35 is sealed to the tubing 27 via a sealing member which in this embodiment is an 0-ring 37.
In this example the top connector 23 and top coupling 35 are shown as two parts that are joined, but they may be integrally formed.
A central bore 94 is formed in the top connector 23. The central bore 94 is sized to receive the plug 26. The nut 24 secured the plug 26 to the top connector 23 to prevent fluid from passing through the central bore 94.
An intermediate portion of the assembly 20 is shown in Figure 7. The portion shown corresponds to a junction between stacked membrane contactors 1 which form a part of the membrane contactor assembly 20. The intermediate connector 22 fluidly connects end faces 6 of two membrane contactors 1 to the intermediate coupling 40 which is connected to gas transfer tubing 27. This connection allows for vacuum or gas to be supplied or drawn to or from both of the two membrane contactors 1, specifically to the hollow bores of the fibres in the hollow fibre structure 4 within the contactors 1. This ensures that gas or vacuum pressure may be evenly distributed through the assembly 20. Even distribution of gas or vacuum pressure ensures degassing occurs evenly through the assembly which allows for an increase in flow rates beyond conventional flow rates of membrane contactors 1.
The intermediate connector 22 is generally disc shaped and matches the general shape and configuration of the membrane contactors 1. A chamber 44 is formed within the intermediate connector 22 proximate the end faces 6 of both membrane contactors 1. In this example the chamber 44 is formed by a labyrinth structure. The labyrinth structure comprises a downward facing lip 42 projecting from a portion 41 of the intermediate connector 22, and an upward facing lip 43 projecting from an opposite sidewall of the intermediate connector 22. The chamber 44 provides for fluid communication of gas or vacuum to the bores of the hollow fibres in the hollow fibre structures 4 of the membrane contactors 1.
The intermediate connector 22 and portion 41 are depicted as a single element, but may be formed as two separate parts.
The labyrinth structure may direct any liquids which may pass through the walls of the hollow fibres or the potting 5 into the gas transfer tubes 27 so that the liquids do not collect on top of the end face 6 of the potting 5 of lower membrane contactor 1 where liquid may impair the collection or delivery of gasses to or from the bores of the hollow fibres.
The labyrinth structure is arranged to not negatively affect vacuum or gas pressure which may reduce degassing efficiency of the assembly 20.
While a particular configuration has been illustrated and described one of skill in the art will appreciate that other configurations within the chamber 44 are possible. For example a membrane may be positioned within the chamber through which liquid cannot pass, but vacuum and gas can. Special care would need to be paid to ensure the membrane does not impair the gas or vacuum pressure which may reduce degassing efficiency of the assembly 20.
The intermediate connector 22 is sealed to the outer tube 2 and inner tube 3 of the membrane contactors 1 by sealing members. In example, the sealing members are 0-rings 31 and 32.
The chamber 44 is fluidly connected to the intermediate coupling 40 via passages 45, 46. The intermediate coupling 40 is connected to gas transfer tubing 27 which is received in an upper socket 96 and a lower socket 98. Gas transfer tubing 27 is secured within the upper socket 96 via a sealing member which in this example comprises an 0-ring 37, and gas transfer tubing 27 is secured within the lower socket 98 via a sealing member which in this example comprises an 0-ring 37.
Vacuum or gas is communicating from or to the gas transfer tubing 27 via the passages 45, 46 in the intermediate coupling 40 and to the bores of the hollow fibres in the membrane contactors 1 via the chamber 44.
In this example the intermediate connector 22 and intermediate coupling 40 are depicted as two parts that are joined, but they may be integrally formed.
A lower or bottom end of the assembly 20 is shown in Figure 8. This end of the assembly 20 is adapted to receive vacuum or gas for degassing a liquid. This end is also adapted to receive liquid to be degassed. While not shown in Figure 8, the assembly 20 may located within a vessel as will be described. The lower or bottom end of the assembly 20 depicts the bottom or lower end of one of the membrane contactors 1. The bottom connector 21 fluidly connects the lower end of the lower or bottom most membrane contactor 1 to a gas plenum 72. Vacuum or gas is communicated to a chamber 65 in the bottom connector 21 which is fluidly connected to the passages 61, 62, 63 as described below. Gas transfer tubing 27 communicates gas or vacuum to the upper end of the contactor 1 which is not shown in Figure 8. The lower end of the contactor 1 communicates with the gas plenum via chamber 60, passages 61 and chamber 65.
The bottom connector 21 is generally disc shaped and matches the general shape and configuration of the membrane contactors 1. A chamber 60 is formed within the bottom connector 21. The chamber 60 allows for vacuum or gas to fluidly communicate with the hollow fibres. A passage 61 in the bottom connector 21 fluidly connects the chamber 60 to chamber 65. The passages 62, 63 fluidly connect chamber 65 to the bottom coupling 64. Gas transfer tubing 27 is secured to the bottom coupling 64 via a socket 96a. The gas transfer tubing 27 is sealed to the bottom coupling 64 via a sealing member which in this example comprises an 0-ring 37. Passages 61 and 63 are in fluid communication with a gas plenum 72 via chamber 65.
Vacuum or gas is communicated from or to the gas plenum 72 through chamber 65 and passages 62, 63 to or from the gas transfer tubing 27 for degassing a liquid. Vacuum or gas is communicated to or from the gas plenum 72 through chamber 65 and passages 61 to the chamber 60 and to bores of hollow fibres for degassing a liquid.
The assembly 20 further comprises the liquid transfer pipe 50 which supplies liquid to be degassed to the central transfer tube 90 of the assembly 20. The liquid transfer pipe 50 is sealed to a socket 54 via a sealing member which in this example is an 0-ring 52.
The outer surface 55 of the socket 54 may contact the bottom connector 53. The socket 54 is sealed to the inner tube 3 of the lower most membrane contactor 1 via a sealing member which in this embodiment is an 0-ring 32. In this manner liquid flowing through the liquid transfer pipe 50 is prevented from entering the chamber 60 and interfering or negatively affecting degassing.
The liquid transfer pipe 50 is further sealed to a gas transfer plate 71 via a sealing member which in this example is an 0-ring 51.
The bottom connector 21 and/or spigot 28 is sealed to a partition plate 70 via a sealing member which in this example is an 0-ring 29.
The partition plate 70 and gas transfer plate 71 define the gas plenum 72 therebetween.
As shown in Figure 8 the bottom connector 23 may be integrated with the spigot 28. In another example, the elements are separate components.
In this example the bottom connector 21 and bottom coupling 64 are depicted as two parts that are joined, but they may be integrally formed.
As shown in Figures 9 and 10, the bore of the spigot 28 is greater or larger than the outer diameter of the liquid transfer pipe 50. This allows for angulation of the liquid transfer pipe 50 relative to the central transfer tube 90.
As shown in Figure 9, the hole 58 in the gas transfer plate 71 is not concentric with the hole 57 in partition plate 70 and the liquid transfer pipe 50 has angulated to accommodate this eccentricity. The eccentricity may occur because of positional tolerances relating to the machining of the holes 57, 58 in the plates 70, 71, because of errors in assembly, or because the plates 70, 71 are made from materials with different coefficients of thermal expansion.
As shown in Figure 10, the 0-ring lands 86 either side of the 0-ring 51 are formed as a spherical surface 87 centred in the plane in which the mid width of the 0-ring groove 59 lies so that they can angulate without jamming in the hole 58. Alternatively the lands 86 may be approximated by one or more conical surfaces to simplify manufacture.
Angulation of a few degrees causes only a small increase of the distance between the base of the 0-ring groove 59 and the bore of the hole 58 so that by choice of a suitably sized 0-ring 51 that maintains sufficient compression when angulated the sealing between chambers 73 and 72 can be maintained. This arrangement may also be used with 0-ring 52 at the upper end of the liquid transfer pipe 50 so that it can angulate within sealing surface 56 without jamming and maintain the necessary sealing to prevent liquid entering into the gas plenum 72.
At the upper end of the liquid transfer pipe 50 another 0-ring 53 is used to retain the liquid transfer pipe 50 in the bottom connector 21 so that it does not fall out during insertion or removal of the assembly 20 into a vessel as will be described.
In use, liquid to be degassed is fed from a feed chamber 73 up the liquid transfer pipe 50. The liquid is prevented from entering the chamber 60, passages 61, 62, 63 or gas plenum 72 by the various sealing members and socket 54 as described. The liquid is fed into the central transfer tube 90 of the assembly 20 and through holes 92 in the tube 90. The liquid then passes through the holes 9 in the inner tube 3 and into the annulus between the tubes 2, 3. The liquid is drawn through the hollow fibre structure 4 then passes through the holes 8 in the outer tube 2 of the membrane contactors 1 of the assembly 20.
Gas or vacuum is passes via the gas plenum 72 through the chamber 65 and passages 61 into the chamber 60 and through the bores of the hollow fibres of the hollow fibre structure 4 of the lower most membrane contactor 1. Gas or vacuum also passes via the gas plenum 72 through the chamber 65 and the passages 62, 63 into gas transfer tubing 27. Gas or vacuum communicated via gas transfer tubing 27 passes through passages 45, 46 into chamber 44 to flow through the hollow fibres of the hollow fibre structure 4 of one or more intermediate membrane contactors 1. Gas or vacuum communicated via gas transfer tubing 27 also passes through passages 36 and 34 into chamber 33 to flow through the hollow fibres of the hollow fibre structure 4 of the upper most membrane contactor 1. The gas or vacuum flowing through the various bores of the hollow fibres degasses the liquid in the manner previously described.
The degassed liquid passes from the annulus defined by the tubes 2, 3 through holes 8 into an outlet chamber 74 where it may be used in various applications.
Generally the liquid to be degassed is fed up through the assembly 20 while gas or vacuum flows in the opposite direction. The liquid flows through a central portion of the assembly 20 then radially thru the membrane structures 4 of the contactors 1 in the assembly 20. The gas may flow upwards in the upper half of the assembly before flowing downwards in the gas transfer tubing 27.
The described assembly 20 may be used in an apparatus for degassing a liquid. Such an apparatus is depicted in Figures 11 and 12. The apparatus comprises a pressure vessel 83. The vessel 83 is formed by a central cylindrical section 76 and upper and lower domed cap sections 77 and 75, respectively, mounted to opposing ends of the central section 76 via respective flange joints. Guide plate 81 and partition plate 70 are mounted within the vessel 83 to define an upper chamber 100, a lower or feed chamber 73 and an outlet chamber 74. The periphery of the guide or upper partition plate 81 is clamped and sealed between the central and upper cap sections 76 and 77 of the vessel 83 at the region of a flange joint. Similarly, the periphery of the lower or simply partition plate 70 is clamped and sealed between the central and lower cap sections 76 and 75 of the vessel 83 at the region of flange joint. Additionally the gas transfer plate 71 is clamped between central and lower cap sections 76 and 75. Spacer 84 separates the partition plate 70 and gas transfer plate 71 to define the gas plenum 72. Additional spacers 84 may be present through the gas plenum 72 to ensure even spacing between the plates 70, 71. The gas plenum 72 is within the lower chamber 73, but it not fluidly accessible via the lower chamber 73.
The upper, lower and outlet chambers 100, 73 and 74, respectively, may also be referred to as the first, third and second chambers, respectively.
The apparatus further comprises a plurality of membrane contactor assemblies 20 within the outlet chamber 74. The assemblies 20 are mounted to the plates 81, 70 and 71. The upper ends of the assemblies 20 are located within the vessel 83 by the guide plate 81 and the lower ends sit on the partition plate 70. The spigot 28 on the lower end of each assembly 20 is inserted and sealed in holes 57 in the partition plate 70 with the liquid transfer pipe 50 projecting from the spigot 28 into holes 58 in the gas transfer plate 71.
The vessel 83 includes a number of ports to facilitate fluid communication to and/or from the vessel 83 as will be described.
A feed or lower chamber 73 is formed in the lower domed cap section 75 of the vessel 83. The feed chamber 73 contains liquid to be degassed which is fed from an inlet nozzle 78. An outlet chamber 74 is formed within the central section 76 of the vessel 83. The outlet chamber 74 receives degassed liquid from the assemblies 20 within the central section 76. An upper chamber 100 is defined within the upper section 77 of the vessel 83. Degassed liquid passes through holes 82 in the guide plate 82 from the outlet chamber 74 into the upper chamber 100 and through an outlet nozzle 79. A gas nozzle 80 is in fluid communication with the gas plenum 72.
The vessel 83 accordingly defines four separate chambers, the upper chamber 100 within the upper section 77, the outlet chamber 74, the gas plenum 72 in the lower section 75 and the feed chamber 73 in the lower section 75. The upper chamber 100 and the outlet chamber 74 are in fluid communication via the holes 82 in the guide plate 81. The gas plenum 82 and feed chamber 73 are sealed relative to each other such that liquid from the feed chamber 73 cannot enter the gas plenum 72 or gas nozzle 80, and vacuum or gas in the gas nozzle or gas plenum 72 cannot enter the feed chamber 73 or inlet nozzle 78. The outlet chamber 74 is sealed from the gas plenum 72. Liquid in the outlet chamber 74 is prevented from flowing through the openings in the partition plate 70 in which the assemblies 20 are located. The 0-ring 29 provides a sealed connection in the partition plate 70 such that liquid from the outlet chamber 74 does not flow into the gas plenum 72.
As shown in Figure 12 thirty-eight (38) assemblies 20 are located within the vessel 83. As one of skill in the art will appreciate more or fewer assemblies 20 may be located within the vessel 83. The vessel 83 may be larger or smaller to accommodate any number of assemblies 20.
As described membrane contactors 1 may have flow rates of 28.4 or 50 m3/hour. Using four membrane contactors 1 in the described assembly 20 may allow for this flow rate to be multiplied by a factor of four, i.e. up to 200 m3/hour. Including thirty-eight assemblies 20 in a single vessel 83 may further multiply the flow rate to reach or a required flow rate required of particular applications, e.g. 1600 m3/hour, such as the provision of degassed, deaerated or deoxygenated water in oil and gas applications.
The described gas plenum 72 ensures vacuum or gas and liquid do not mix reducing the efficiency of the degassing process.
In use, liquid is fed through the inlet nozzle 78 into the feed chamber 73. The liquid enters the liquid transfer pipe 50 of each assembly 20. The liquid transfer pipe 50 is sealed at the gas transfer plate 71 to ensure liquid does not pass into the gas plenum 72. Additionally the liquid transfer pipe 50 is sealed to the inner tube 3 of the lowermost membrane contactor 1 to ensure liquid does not pass into bores of hollow fibres in the hollow fibre structure 4 in the membrane contactor 20. The liquid flows through the central transfer tube 90 of the respective membrane contactor 20 and through holes 92 in the tube 90. The liquid then passes through holes 9 in the inner tube 3 and enters the annulus between the tubes 2, 3. The liquid is then degassed by vacuum or gas flowing through the bores of the hollow fibres in the hollow fibre structure 4 of the membrane contactor 1. The degassed liquid passes through holes 8 in the outer tube 2 and into the outlet chamber 74. The degassed liquid then flows through holes 82 in the guide plate 81 and into the upper chamber 100. The degassed liquid then flows out through the outlet nozzle 79 ready for use.
Vacuum or gas is provided from a vacuum or gas source via the gas nozzle 80 which is fluidly connected to the gas plenum 72. The vacuum or gas enters the gas plenum 72 and flows through the chamber 65 and passages 62, 63 into gas transfer tubing 27. This vacuum or gas is communicated to intermediate membrane contactors 1 which are stacked on top of the lower most membrane contactor 1. This vacuum or gas enters or is extracted from passages 45, 46 and chamber 44; and passages 34, 36 and chamber 33. The vacuum or gas also flows through the passages 61 through chamber 60 into the bores of the hollow fibres of the hollow fibre structure 4 of the lower most membrane contactor 1 of the assembly 20. Both of the flows degas liquid within the annulus of the tubes 2, 3 of the respective membrane contactors 1. Accordingly, the vacuum or gas is evenly distributed to the membrane contactors 1 of the assembly 20 to ensure efficient degassing of the liquid.
The apparatus for degassing a liquid may be assembled or manufactured by first assembling the gas transfer plate 71, the spacer 84 and the partition plate 70 between the lower cap section 75 and the central section 76 of the vessel, then inserting membrane contactor assemblies 20 into the central section 76 of the vessel so that they sit on the partition plate 70 with their spigots 28 located and sealed to the holes 57 in partition plate 70 and their liquid transfer pipes located and sealed in the holes 58 in the gas transfer plate 71 then fitting guide plate 81 onto the upper end of the central section 76 of the vessel so that the plugs 26 of the membrane contactor assemblies project through the holes in the guide plate to restrain lateral movement of the upper end of the assemblies then refitting the upper cap section 77 to the central section 76 of the vessel.
While sealing members have been described in examples as 0-ring, one of skill in the art will appreciate that other sealing members may be used.
While particular numbers of membrane contactors and intermediate connections have been described, one of skill in the art will appreciate that more or fewer may be present.
While the assembly and vessel have been described with reference to top, bottom, up and/or down one of skill in the art will appreciate these spatial relationships have been presented as exemplary only and the subject disclosure is not limited to the described orientations.
Although embodiments have been described above with reference to the figures, one of skill in the art will appreciate that variations and modifications may be made without departing from the scope thereof as defined by the appended claims.

Claims (48)

  1. CLAIMS: 1. A membrane contactor assembly for degassing a liquid, the assembly comprising a housing having open top and bottom ends, and a hollow fibre structure disposed within the housing, the top end of the housing adapted to receive gas or vacuum for degassing a liquid, the bottom end of the housing adapted to receive gas or vacuum for degassing a liquid, and at least one intermediate opening in the housing intermediate the top and bottom ends adapted to communicate gas or vacuum for degassing a liquid to the hollow fibre structure.
  2. 2. The assembly of claim 1, wherein the intermediate opening is located between two hollow fibre structures within the housing such that gas or vacuum for degassing a liquid is communicable to one or more of the two hollow fibre structures.
  3. 3. The assembly of any preceding claim, wherein the intermediate opening defines a chamber within the housing.
  4. 4. The assembly of claim 3, wherein the chamber is defined between hollow fibre structure disposed within the housing.
  5. 5. The assembly of claim 3 or 4, further comprising a liquid diverter within the chamber for preventing liquid from one hollow fibre structure from entering another hollow fibre structure.
  6. 6. The assembly of claim 5, wherein the liquid diverter comprises a structure adapted to direct fluid from a hollow fibre structure to a gas or vacuum source.
  7. 7. The assembly of claim 5 or 6, wherein the liquid diverter comprises a labyrinth structure.
  8. 8. The assembly of claim 6 or 7, wherein the structure forms an declined surface relative to a flow path of liquid from a hollow fibre structure of the assembly to direct liquid to a gas or vacuum source.
  9. 9. The assembly of claim 8, wherein the structure forms two surfaces which overlap relative to the flow path.
  10. 10. The assembly of claim 9, wherein the overlapping surfaces are formed by opposing lips projecting from sidewalls of the chamber.
  11. 11. The assembly of claim 10, wherein the opposing lips project at supplementary angles
  12. 12. The assembly of claim 10 or 11, wherein the opposing lips define a serpentine flow path.
  13. 13. The assembly of any one of claims 10 to 12, wherein one of the lips projects downwardly relative to the lateral axis of the assembly and another of the lips projects upwardly relative to the lateral axis of the assembly.
  14. 14. The assembly of any one of claims 3 to 13, wherein the chamber is connectable to gas transfer tubing to supply a gas or vacuum.
  15. 15. The assembly of any preceding claim, wherein the hollow fibre structure comprises a bundle of hollow fibres.
  16. 16. The assembly of any preceding claim, further comprising end caps affixed to each open end of the housing.
  17. 17. The assembly of any preceding claim, wherein the assembly comprises at least two stacked membrane contactors for degassing a liquid, each membrane contactor comprising a housing having open ends and a hollow fibre structure disposed within the housing, wherein the housing of the assembly is defined by the housings of the membrane contactors, and wherein the intermediate opening is located between adjacent stacked membrane contactors.
  18. 18. The assembly of claim 17, further comprising end caps affixed to each open end of the housing of the membrane contactor.
  19. 19. The assembly of claim 17 or 18, further comprising a lowermost connector adapted to form a socket for connection to a liquid transfer pipe for supplying liquid to be degassed.
  20. 20. The assembly of claim 19, further comprising: a liquid transfer pipe fluidly connected to the spigot, the liquid transfer pipe for supplying liquid to be degassed.
  21. 21. The assembly of any one of claims 17 to 19, further comprising: a plug connectable to an uppermost connector of the assembly.
  22. 22. The assembly of any preceding claim, wherein the top end of the housing is connectable to gas transfer tubing to supply a gas or vacuum.
  23. 23. The assembly of any preceding claim, wherein the bottom end of the housing is connectable to gas transfer tubing to supply a gas or vacuum.
  24. 24. The assembly of any preceding claim, wherein a liquid to be degassed is water.
  25. 25. An apparatus for degassing a liquid, the apparatus comprising: a vessel; a partition plate dividing the vessel into first and second chambers; at least one of the assembly of any preceding claim located within the second chamber.
  26. 26. The apparatus of claim 25, further comprising: a gas transfer plate located within the first chamber, the gas transfer plate and the partition plate defining a gas plenum therebetween for supplying vacuum or gas to the assembly for degassing a liquid.
  27. 27. The apparatus of claim 26, further comprising at least one liquid transfer pipe for supplying liquid to be degassed to the assembly.
  28. 28. The apparatus of claim 27, wherein the liquid transfer pipe is adapted to sealingly engage a central bore of the assembly.
  29. 29. The apparatus of claim 27 or 28, wherein the liquid transfer pipe is positioned within an aperture in the partition plate.
  30. 30. The apparatus of claim 29, wherein the liquid transfer pipe is positioned within an aperture in the gas transfer plate.
  31. 31. The apparatus of claim 30, wherein the aperture in the gas transfer plate defines a smaller width than the aperture in the partition plate.
  32. 32. The apparatus of claim 30 or 31, wherein the liquid transfer pipe is sealed relative to sidewalls of the aperture in the gas transfer plate.
  33. 33. The apparatus of claim 32, wherein the liquid transfer pipe is sealed relative to sidewalls of the aperture in the gas transfer plate such that angulation of the liquid transfer pipe relative the assembly is permitted.
  34. 34. The apparatus of claim 32 or 33, wherein the liquid transfer pipe is sealed with an 0-ring
  35. 35. The apparatus of claim 34, wherein the 0-ring is positioned in a ring groove in the liquid transfer pipe.
  36. 36. The apparatus of claim 35, wherein 0-ring lands adjacent the ring groove in the liquid transfer pipe partially form a spherical surface.
  37. 37. A method of degassing a liquid, the method comprising: drawing a liquid to be degassing through into a central bore of a housing of a membrane contactor assembly, the housing having open top and bottom ends, the membrane contactor assembly further comprising a hollow fibre structure disposed within the housing; the top end of the housing adapted to receive gas or vacuum for degassing a liquid; the bottom end of the housing adapted to receive gas or vacuum for degassing a liquid; and at least one intermediate opening in the housing intermediate the top and bottom ends adapted to communicate gas or vacuum for degassing a liquid to the hollow fibre structure; drawing a liquid to be degassed through perforations in the housing such that liquid passes over the hollow fibre structure; and passing a gas or vacuum through an interior space of the hollow fibre structure via the top end, bottom and intermediate opening to degas a liquid.
  38. 38. A method of manufacturing an apparatus for degassing a liquid, the method comprising: assembling a gas transfer plate and a partition plate to define a gas plenum; and positioning the membrane contactor assembly of any one of claims 1 to 24 on the partition plate.
  39. 39. The method of claim 38, wherein assembling the gas transfer plate and the partition plate comprises providing one or more spacers between the plates to define the gas plenum.
  40. 40. The method of claim 38 or 39, further comprising: locating the assembly within an aperture of the partition plate.
  41. 41. The method of any one of claims 38 to 40, further comprising: fitting a guide plate to an upper end of the assembly opposite the partition plate.
  42. 42. A membrane contactor assembly for degassing a liquid, the assembly comprising a housing having open top and bottom ends, and a hollow fibre structure disposed within the housing, the top end of the housing adapted to receive gas or vacuum for degassing a liquid, and the bottom end of the housing adapted to receive gas or vacuum for degassing a liquid, the assembly further comprising: a liquid transfer pipe for supplying liquid to the assembly, the liquid transfer pipe sealed to the housing such that gas or vacuum communicated to the housing is prevented from entering the liquid transfer pipe.
  43. 43. The assembly of claim 42, wherein gas or vacuum supplied to the housing is suppling from a gas plenum.
  44. 44. The assembly of claim 43, wherein the gas plenum surrounds the liquid transfer Pipe.
  45. 45. An apparatus for degassing a liquid, the apparatus comprising: a vessel; a partition plate dividing the vessel into first and second chambers; and at least one assembly of claim 42 to 44 located within the second chamber.
  46. 46. The apparatus of claim 45, further comprising: a gas transfer plate located within the first chamber, the gas transfer plate and the partition plate defining a gas plenum therebetween for supplying vacuum or gas to the assembly for degassing a liquid.
  47. 47. The apparatus of claim 46, wherein the liquid transfer pipe is positioned within an aperture in the partition plate.
  48. 48. The apparatus of claim 46 or 47, wherein the gas plenum surrounds the liquid transfer pipe.
GB2102947.5A 2021-03-02 2021-03-02 Membrane contactor assembly for degassing a liquid Pending GB2604591A (en)

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Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020138096A1 (en) * 2018-12-28 2020-07-02 Dic株式会社 Degassing system, method for degassing liquids, degassing unit, degassing module, and degassing-system manufacturing method and method of production from natural resources

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020138096A1 (en) * 2018-12-28 2020-07-02 Dic株式会社 Degassing system, method for degassing liquids, degassing unit, degassing module, and degassing-system manufacturing method and method of production from natural resources

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