MXPA98006694A - Contactor to degasify liqui - Google Patents

Abstract

A contactor for degassing liquids includes a perforated core, several hollowed-out microporous fibers and a shell, the fibers surround the core and have two ends, a tube sheet fixes the ends of the fibers, a screen is located between the tube sheets, the fibers hollowed out are closed in the screen, the shell encloses the fibers, the tube sheets and the screen, the system for degassing liquids includes a source of liquid containing a gas, a vacuum source and the contact

Description

í. CONTACTOR FOR DEGASING LIQUIDS FIELD OF THE INVENTION This invention is a contactor and a system for degassing liquids.

BACKGROUND OF THE INVENTION? IO Contactors capable of separating fluids are known f for example see the patents of E.U.A. 4 »220» 535 »5,264,171; and 5, 352 »3S1 > which are mentioned by way of reference. These contactors consist of a perforated central tube, several recessed fibers that surround the tube »sheets of pipe that fix the ends of the recessed fibers »a screen placed between the sheets of the tube and a shell that surrounds the tube» the fibers »the sheets of the tube and the screen. The fibers »however, are not closed in 1 a screen» but on the contrary they are open »for there to be a communication of the fluid through the opening of the hollow fiber from one tube sheet to the other. Contactors capable of separating fluids, for example »dissolved gas from water» have several industrial applications. These applications include: systems oxidation prevention for boilers or plant power turbines; oxidation prevention systems for water ^ drinking water, cooling water or hot water pipes; ultrapure water sources for the electrical industry (for example »semiconducting rinsing olbeas during manufacturing); ultrasonic cleaning procedures; 5 water sources for food processing; and similar. Two of the above applications are of particular interest. They are for the prevention of oxidation in water pipes and ultrapure water sources for the electronics industry.

Jv In each application, the extraction of oxygen dissolved in water ÍO is extremely important. In the prevention of oxidation of water pipes, oxygen reacts with dissolved iron or iron in the pipe to form oxidation that can be precipitated. In drinking water »the oxidation precipitate is not pleasant and causes stains; and in the pipes »can cause the occlusion of the pipe. In ultrapure water for ? electronic industry »water is used to rinse 4fl semiconducting olbeas during manufacturing Oxygen dissolved in the rinse water can corrode the surface of the olbea and destroy it, it can also coat the surface of the the olbea and prevent effective rinsing. Therefore, the extraction of dissolved gases from water is extremely important. Therefore »there is a need to develop new contactors and systems to degas liquids.

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This invention is a contactor and a system for degassing a liquid. 5 The contactor includes a perforated core »several hollowed microporous fibers and a shell. The fibers surround the nucleus and have two ends. A sheet of the tube fixes the ends of the fibers. A screen is located between the sheets of the tube, the hollow fibers are close to the IO screen. The shell encloses the fibers »the sheets of the tube and the screen. The system for degassing liquids includes a source of liquid containing a gas »a source of vacuum and contactor. The liquid source is in fluid communication with one end of the core. The vacuum source is in communication "Fluid with the openings of the fibers recessed through the sheets of the tube." The liquid passes the nucleus "through the fibers" around the screen, through the fibers and back into the nucleus. DRAWINGS For the purpose of illustrating the invention, a form which is currently preferred is shown in the drawings; without However, it should be understood that this invention is not limited to the precise arrangements and instrumentalities that are) show Figure 1 is a schematic illustration showing a system for degassing a liquid. Figure 2 is a sectional view of a first embodiment of the contactor of the invention. Figure 3 is a sectional view of a second embodiment of the contactor of the invention. Figure 4 is a sectional view of a third embodiment of the contactor of the invention. IO Figure 5 is a graphical comparison of the total mass transfer coefficient as a function of the flow velocity (liquid) of several contactors (of the invention and others).

DETAILED DESCRIPTION OF THE INVENTION k * 4jfl With reference to the drawings "where similar numbers indicate similar elements" a schematic illustration of system 10 is shown in figure 1. System 10 is for degassing liquids. The system 10 generally consists of a contactor 12 (which is described in more detail below) »a vacuum source 14, an inlet 16 for gas liquid»? An outlet IB for the degassed liquid. The vacuum source 14 is interconnected to contactor 12 by vacuum pipe 20. The vacuum is transported from both ends of contactor 12. ß- .- (The importance of this configuration will be described in more detail later). The liquid with gas is fed into the inlet 16 of the contactor 12. The degassed liquid is extracted from the outlet 18 of the contactor 12. (The operation of the contactor will be described in more detail later). More details about the operation of system 10, with respect to specific applications, will be discussed later. With reference to figures 2, 3 and 4 »the contactor IO 12 generally consists of a perforated core 24 »several recessed fibers 26 surrounding the core 24» sheets of tube 23 at the ends of the fibers 26 »a screen 30 between the sheets 2B and to hold the fibers 2S» and a shell 32 that surrounds the core »the fibers» the sheets and the screen. He contactor 12 is a mass transfer device in which the liquid containing dissolved gas is introduced via the inlet 16 and the core 24. The core 24 preferably includes a diverter 25. The diverter 25 is a block in the core 24 that prevents direct communication flow from the 1S input to the IB output. The liquid passes outside the core 24. The liquid flows through the fibers 26"around the screen 30" through the fibers 2S and back to the core 24 and exits through the outlet 18. The contactor 12 is in fluid communication with the source of vacuum 14 through the pipe 20. The pipe 20 is in communication with the vacuum head space 34. The space m. of head 34 and the opening of the recessed fiber 26 are in communication. In general, the contactor 12 is constructed as set forth in the U.S.A. Nos. 5 »264, 171 and 5,352,361, both are mentioned by way of reference. In the preferred embodiment, the core 24 is tubular and coaxial with the shell 32; the screen 30 is equidistant from the sheets of the tube 28 and is in contact with the core 24; the diverter 25 is coplanar j? with the screen 3 ?; and the recessed fibers 26 and the density of the recessed fibers 26 »on both sides of the screen 30 are identical. However, the invention is not limited to this. The difference between the contactors illustrated in Figures 2, 3 and 4 refers to the term 36 of the recessed fiber 26 which is preferred inside the bulkhead 30. By example »in Figure 2, the terms 36 of the f rows 26 are 3 united. The hollowed fibers are preferably pressed in * < j the fiber mat before being blown to the core 24, the terms 36 are formed by a welding device »for example» heat, ultrasonic »etc. In figure 3 »a modality alternating is illustrated. There, the terms 36r inside the screen 30 are physically cut and formed in block. In figure 4 »the terms 36 't are formed in the thin portions of the screen 30" and 30t In operation »the mass transference of the gas Dissolved from the liquid is improved by the designed contactor of the invention. As with all mass transfer devices, transportation is driven by the concentration gradient. In this invention, the concentration gradient is maximized in the concurrent and countercurrent flow by drawing the vacuum from the two ends of the tube sheets of the recessed fibers. This is illustrated below with reference to Fig. 5. In Fig. 5 »a comparison of total mass transfer coefficient» KOA (meter / hour, m / h >; »The y-axis» as a function of the liquid flow velocity (cubic meter / hour »m .. ,, / h), x-axis» is made up of several contactors. In each example »the contactor was opened at 25 ° C; 18 torr; and 8500 mg / m3 (ppb) of oxygen dissolved in water. Curve 1 is a contactor-made in accordance with this invention and has an outer recessed fiber surface area of 19.3 square meters (CELGARD hollow fiber "X-40" commercially available from Hoechst Celanese, Separation Products Group of Charlotte , North Carolina »USA, is used as the membrane.) Curve 2 is a contactor having an outer recessed fiber surface area of more than 30 square meters and is commercially available from Dianippon InK and Chemical, Inc. of Tokyo, Japan (the contactor is identified as SEPAREL "EFM-530 GM112). Curve 3 is a contactor having a recessed outer fiber surface area of 19.3 square meters and is made in accordance with US Patents. Nos. 5,264,171 and 5,352,361 and marketed under the trade name LIQUI-CELR contactors by the Hoechst Celanese company »Separation Products Group of Charlotte, North Carolina» E.U.A .; the recessed fiber membrane is the CELGARDR X-40 fiber mentioned above. Curve 4 is a contactor having an outer hollow fiber surface area of 19.3 square meters and is made in accordance with US Patents. Nos. 5,264,171 and 5,352,361, except that no bulkhead was used; the recessed fiber membrane is the CELGARDR X-0 fiber mentioned above. The curves of Figure 5 were generated in accordance with the following formula KOA A / Q = ln (Ci / Co) where: KOA is the total mass transfer coefficient (m / h) A = outer membrane surface area (m52) Q = fluid fluid velocity (m3 / h) C = concentration of dissolved gas »0 .. ,, = input, or = output In the application for the prevention of industrial water oxidation, industrial water typically it has an oxygen content greater than or about 9000 parts per billion (ppb). In most industrial applications, oxygen must be extracted to the content of less than 500 ppb.

Using the contactor of the invention, this can be achieved with a vacuum of less than 50 torr and a contactor having approximately IB square meters.

In general, the system can be used in any gas degassing process. Those other procedures include extracting oxygen from the kettle's water feeder to prevent corrosion, extracting carbon dioxide from the water to prolong the life of the disniza- tion resin between regeneration and those previously mentioned. . The vacuum source can vary from 125 torr to 18 torr. This invention may be included within a form in other specific forms without departing from the essential attributes thereof, and, therefore, reference should be made to the appended claims, rather than the above specification as they indicate the scope of the invention. the expiration.

Claims (9)

NOVELTY OF THE INVENTION CLAIMS

1. - A contactor consisting of: a perforated core; several hollowed microporous fibers surrounding said core »said fibers have two ends, a tube sheet that fixes said ends, a screen that is located between said tube sheets and said fibers are near said screen; and a shell that encloses said fibers, sheets of tube and screen.

2. The contactor according to claim 1, characterized in that said fibers are pressed closely. 3.- The contactor in accordance with the rei indication 1, characterized in that said fibers are closed by cutting and blocking. 4. The contactor according to the re indication 1, characterized in that said screen consists of two fine halves, said end fibers have a term in one of said halves. 5. A system for degassing liquids consisting of: a source of liquid containing a gas »a source of vacuum; and a contactor consisting of a perforated core, several recessed microporous fibers containing openings surrounding said core, said fibers having two ends, a sheet of tube that fixes said ends, a screen that is located between said sheet of tube, and said fibers are closed in said screen, and a shell enclosing said fibers »sheets of tube, and screen; characterized in that said liquid source is in fluid communication with one end of said core, said source of vacuum is in fluid communication with said openings through said tube sheets, said liquid surpasses said core, through said fibers, around said partition »through said fibers» and said nucleus passes back. 6. The system according to the indication 5 »characterized in that said liquid is water. 7. The system according to the rei indication 5, characterized in that said source of vacuum varies from 125 torr to 8 torr. 8. The system according to the re-indication 5 »characterized in that said system is used for the prevention of oxidation. 9. The system in accordance with the claim 5 »characterized in that said system is used as a source of ultrapure water.