FI118632B - Method and apparatus for feeding media needed for microflotation into a process fluid - Google Patents

Description

1 118632

A method and apparatus for feeding media required for microflotation into a process fluid

The present invention relates to a method and apparatus for feeding media required for microflotation into a process fluid. Particularly preferably, the method and apparatus of the invention is used, for example, in the treatment of slurry, where necessary mixing said polymers with a process fluid to be purified, preferably among a process impure liquid, such as filtrate or crude process fluid.

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Micro-flotation, also known as DAF or "dissolved air flotation", is particularly known as a water purification method in which very small air bubbles less than 100 µm in diameter are directed to water to be purified, the mucus bubbles being produced from air-saturated recycled water. This 15 air saturated water is led to a flotation tank via pressure relief means. When the pressure of the water flow suddenly decreases, the air is released in the form of small bubbles, whereby the flocs and bubbles of the water to be treated adhere to one another and the combinations are raised in a controlled manner to the surface of the tank.

• »: ***. 20 The smaller the bubbles that can be produced, the greater the number of bubbles that can be ··· • released per volume of gas. This increases the possibility of targeting bubbles and flocs. In practice, the size of the bubbles varies from 10 to 120 µm and the mean value of V is between 40 and 70 µm. There are always macro bubbles in the air suspension that are larger than 150 µm in diameter. They can damage micro-bubble-flock combinations rising to the surface.

In known methods, water and compressed air are mixed in a pressurized reactor or dispersion water tank. If necessary, the water pressure is increased by a separate pressure boost pump. Depending on the application, the required pressure varies between ·: · 30 3 - 8 bar. The size of the bubbles depends on the pressure used, the dispersion water feed rate and the geometric design of the dispersion feeder. The higher the pressure, the smaller the bubbles are and the higher the amount of P4132; Mattila 2 118632 land is soluble in water. The air-water mixture is kept under pressure until the air is effectively dissolved in water. When the water is passed through the dispersion nozzles into the water to be treated, the pressure suddenly drops and a milky cloud of microscopically small air bubbles form in the water. These small bubbles bind to the solid of the water to be treated or, for example, to oil and grease. Unlike laser-clarifiers, impurities now carry lighter-than-water bubble structures to the surface of the flotator. The resulting surface sludge can be removed either by scraper or overflow by periodically raising the fluid surface of the flotator. Many different solutions have been used in the design of dispersion water nozzle devices to improve the efficiency of bubble formation, for example by directing the flow from the nozzle mouth at a right angle to the impact surface.

The water to be treated can be pre-treated with chemicals before flotation. The Koagu-15 is used to destabilize particles and colloidal charges to form microblocks. Rapid mixing of the coagulant (1-2 sec) reduces the negative charge on the surface of the particles and colloids and renders the hydrophilic particles and colloids more hydrophobic. As a result of surface charge destabilization, ·: ··· particles and colloids merge into microblocks.

:; 20 * ··: Coagulants are generally inorganic compounds such as aluminum and iron compounds or organic compounds such as cationic short chain polymers. Micro-: flocs are combined into larger flocs with flocculant, which is usually an organic polymer of large molecular size. Flocculants are long chain poly-polymers such as polyacrylamides. Polymers also add hydrophobic regions to the surface of the flocs, which allow air bubbles to adhere better to the flocs. For optimal flocculation, chemical mixing must be effective and: · · in the turbulent flow of the entire mass of water. Energy for mixing can be produced by vertical, horizontal and guiding partitions or mechanical mixers.

* ···· • · · · · · ··· P4132; Matula 3 118632

A prior art device for performing microflotation is disclosed e.g. U.S. Patent No. 5,382,358. The apparatus comprises a flotation tank and a mixing device. An untreated liquid is introduced axially into the mixing device at the bottom of the tank, and water saturated with air is introduced from one of the other horizontally into the mixing device. They are mixed in the mixing device and fed into the container through a special helical channel, resulting in microbubbles. Water saturated with air is provided by means of a pressure tank with a pump and a safety valve and a mixer. The supply of chemical in this sample container is proposed to be added afterwards if necessary. Afterwards, getting a Lito is a difficult and often expensive solution. In addition, separate partitions have to be used in this publication to ensure the desired mixing result. Another problem is the correct dosing of chemicals to achieve the desired reaction. This often results in ensuring that the correct reaction occurs and that chemicals are lost due to overdose.

WO Application Publication 96/25362 discloses a device for performing a microflotation process in which the dispersion water and the water to be treated are mixed together in a specific reaction zone. The water to be treated is fed into the unit axially in a separate * *. ···. For 20 ducts and per duct, horizontal inlet and nozzle guided ···:. dispersion water tank. The dispersion water and the water to be treated are mixed within the reaction zone, which can be regulated at a distance from the dispersion water inlet.

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Separate reaction areas reserved for mixing, separated by partitions and ducts, which ensure good mixing results are unnecessary and impractical if the feeder itself is designed to ensure good mixing results.

WO Application Publication 95/27557 discloses a device that forms gas bubbles * »··: ***: in a different fluid of the feeder / nozzle itself to the liquid to be treated. 30 dispersion. Liquid is introduced into the nozzle at the end of the nozzle "··" and the gas is supplied from the second inlet horizontally towards the nozzle. They mix in the dispersion area inside the nozzle, where the size of the bubble is also affected. microflotation processes often require polymers to enhance microflotation reactions, and the feeder of this publication cannot be used to simultaneously supply microbubbles and the necessary polymers to the process liquid.

The prior art solutions presented to produce a microflotation process are very complex and require various adjustment / driving solutions.

The use of separate reaction areas, partitions and other mixing devices is not necessary in the device of the invention. In the invention, mixing with process fluid is so rapid and uniform that no separate reaction areas and partitions are required since the dispersion fluid, such as water, and, if necessary, the polymers can be fed directly to the process fluid from the feeder by a mixing fluid. . According to a preferred embodiment of the invention, microflotation can be carried out without the need for fresh water at all in the process. The dispersion fluid produced in a manner known per se '···: that is, the liquid saturated with air acts as a feed fluid in the apparatus. The dispersion liquid may be: ***: 20 in addition to the pure, clean water brought from outside the process, preferably ···: either the process liquid to be treated, for example sludge, from a flow tube, or a filtrate of the process fluid, i.e., microflot cleansed.

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The mixing of microflotation polymers with process fluid is more efficient and overdose of the polymers can be avoided, since the fast feeding of the polymers with the mixing liquid and the dispersion liquid substantially simultaneously causes the microp in the immediate vicinity there are always polymer particles required for the microflotation process.

* 30 * · ** ·: ** ·: In order to achieve a uniform feed of polymers and dispersion liquid, one or more feeders of * »* or more are arranged at process fluid P4132; Matula 5 118632 is provided on the circumference of the flow pipe, or they can also be arranged such that the flow jets fed from the feeders through the inlet to the process fluid flow pipe cover the entire cross-sectional area of the flow pipe. The feeder or feeders may be located either as close as possible to the microflot pool to avoid, for example, bursting of microbubble and flock combinations in the flow tube due to turbulence, or, if required, the feeder may also be located further away from the microflot pool, for example. The adherence of the microbubbles and the flocs may take place in a flow tube and / or microflot pool.

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Thus, to provide a microflotation process, for example, to a liquid to be purified, a method and apparatus have been found in which the dispersion liquid and polymers required for the microflotation process are substantially more efficient and uniform, and the excessive use of any polymers required can be effectively reduced. The method and apparatus according to the invention, which are solved by e.g. In addition to the problems set forth above, the characteristic features are apparent from the appended claims.

The feeding device according to the invention can be used for the poly- · · · ··. 20 mers, to supply various known microfluorotation polymers to the process fluid. Of the processes, only the inexpensive examples are ··· *. ···. These include precipitation processes of various sludges, recycled fiber processes * · *. *. • Bleaching processes, and in general any process in the chemical, mechanical and • mechanical pulp industry where the supply of chemical to slurry, · · · · · · · · · · · · · · filtrate, culturous suspension or the like is relevant. A preferred process involves treating a slurry of a paper mill, which processes both the process slurry and the bio slurry, wherein the Flok copolymer is fed to the main slurry stream using the bio slurry as: * · *:.

In the following, the method and apparatus of the invention will be explained in more detail with reference to the accompanying drawings, of which P4132; Fig. 1 shows a polymer and dispersion water supply device according to a preferred embodiment of the invention, Fig. 2 shows a polymer and dispersion water supply device according to a preferred embodiment of the invention in an operating position, and Fig. 3 shows practical connections of the device according to the invention to said process.

Figure 1 illustrates a microflotation polymer feeder / mixer according to a preferred embodiment of the invention. Preferably, the feeding device 34 of Fig. 1 consists essentially of a conical body 50, flanges 52 and 54 disposed thereon, preferably, but not necessarily, at its opposite ends, and a joint 56 for the polymer. The feeder 34 is connected by a flange 52 to the dispersion fluid supply pipe 144 and a flange 54 to the process fluid flow pipe. In this embodiment, the dispersion liquid is supplied to the feeder 34 via valve 146 and pipe 144, which is preferably tangential. In the embodiment of the figure, the body 50 of the feeder 34 shrinks from the flange 52 toward the flange 54, the inside of which is the feeder port 58. The conical shape of the body 50 serves to accelerate the dispersion fluid flow in the feeder 34 so that in relation to. Such a ··· • speed difference ensures that the polymer jet and the microbubbles formed from the dispensing liquid at the mouth of the dispenser as a result of the pressure reduction penetrate quickly enough and deep enough to mix with the process fluid substantially more than in prior art applications. The polymer feed inlet 56 in the embodiment shown in the figure is preferably tangential to ensure that the polymer is uniformly distributed at least around the entire orifice 58 when discharged from the orifice 34 to the process fluid. Inside the feeder 34 is a central hollow body 60 inside which the polymer is led from the joint 56.

In other words, the assembly 56 pierces the conical wall 50 of the feeder 34 and the conductor ····; · *. through the annular space between the cone 50 and the piece 60, inside the piece 60 ·· *, preferably supporting the piece 60 in place. Here, P4132; In a matrix 118632 embodiment, the body 60 is axially pierced by a hole 62 for introducing a mixing fluid through valve 164 and pipe 162, which is thereby discharged from the inside of the polymer stream into the process fluid flow pipe. In this embodiment, the polymer flow 5 tangentially directed to the body 60 flows as a helical flow toward the feeder orifice 58, which at the lower end of the body 60 (as shown) has its own annular mouth 64, inside the mouth 64 with the mixing fluid discharged through the hole 62. As a further object, the article 60 still has to strangle the flow cross-section of the feeder to ensure a sufficiently large speed difference between the polymer flow and the process fluid. Another object of paragraph 60 is to allow the polymers to be mixed with the mixing fluid at substantially the same time as the polymers are fed to the process fluid and also to allow rapid pressure drop as close as possible to the dispersion water feed point to prevent the resulting bubbles from colliding. It is clear from the figure that the polymer is not in contact with the mixing fluid at all before it is discharged .. ": from the orifice 64 to the process fluid flow tube.

. * · *. Fig. 2 shows a microflotation process and a microflotation process; a more advanced version of the * * feeder for feeding thiopolymers to the process fluid. It can be used to clean the feeder nozzle if, for example, · the liquid used for mixing is impure and clogs the nozzle of the feeder 25. The feeder 34 in the figure consists of a bottom, i.e. a fluid flow tube jV 70, starting from a substantially cylindrical nozzle body 80 with a conical contraction 82 at the flow end of the conduit 82. The contraction 82 ··· ends in the central inlet 84 · Means 86 for securing the feeder 34 and its nozzle to the process fluid • · · 30 in the sidewall of the nozzle body 80, preferably its cylindrical barrel. on that portion, an opening 88 is provided which communicates with the feed fluid tube connection ♦ · · 144 for supplying the feed fluid to the feed device 34. Nozzle housing 80 P4132; Matula 8 118632 is provided with a circular central opening 90 and a pressurized fluid cylinder 92 extending from the nozzle body 80, the other end of which is formed by an end 94. The opposite end of the pressure medium cylinder 92 has an end-center plate 96, 98, as at the upper end of the nozzle body 80.

The nozzle body 80 extends from above from both openings 98 and 90 of both the ends 96 and 94 of both the polymer and the mixing fluid supply means. ίο These feeders include: a polymer feed pipe 102 in fluid communication with the polymer feed 56 and a mixing fluid feed pipe 104 in turn communicating with the mixing fluid feed pipe 162 which in this embodiment is centrally located within the polymer feed pipe 102 and which are connected to one another at its upper end. The polymer is feed tube 102 is preferably cylindrical for most of its length since in this embodiment it acts as a piston rod of a pressure medium cylinder 92. The actual piston is followed by a piston disk 106 sealed with respect to the pressure medium cylinder 92 and fixed to the outer surface of the polymer feed tube 102. Naturally, both of the pressure medium cylinder 92 • ·. ···. 20 ends 94 and 96 are provided with suitable seals to ensure cylinder operation *. tamiseksi.

The polymer feed tube 102 is provided at its lower end, i.e., the end of the process fluid flow tube 70, located inside the nozzle body 80, with a tapered contraction. 108 which is substantially located at cone 82 of nozzle body 80 and which has the same conicity as conical constriction 82 of nozzle body 80. Preferably, the mandrel 102 of the polymer feed tube 102. the tapered contraction 108 is slightly smaller than the taper angle 82, whereby the flow cross-sectional area between these portions decreases in the flow direction ··· ... 30 faster, resulting in a greater increase in feed rate.

The mixing fluid supply tube 104, in turn, passes centrally within the polymer supply tube 102 and extends somewhat along the P4132 of the polymer supply tube 102; Matula 9 118632 outside of conical constriction 108. The figure further illustrates how the polymer feed tube 102 still preferably, though not necessarily, extends as a cylindrical nozzle tube 110 after a conical shrinkage 108 so as to leave a narrow gap between the mixing fluid feed tube 104 and the wall of the nozzle tube 110 for feed.

In its normal state, the inlet nozzle is in the operating position of Figure 2, whereby both the nozzle tube 110 of the polymer inlet tube 102 and the inlet liquid 104 of the mixing liquid ίο are located substantially outside the nozzle body 80 on the wall of the process fluid. Both the polymer and the feed fluid are fed as a jet in the axial direction of the substantial nozzle body toward the process fluid flow line. Because the mixing fluid is supplied to the end of the feed tube 104 through substantially radially arranged nozzle openings 122, the mixing fluid is discharged in a nearly radial fan, effectively mixing with the bubbles formed from the polymer feed fluid, i.e. the dispersion fluid. By appropriately adjusting the feed pressures, the direction and penetration of the jet and the size of the microbubbles are desired.

• ·: ***. 20 If some solids are left between the conical portions 82 and 108 of the device 34, which cause some blockage, the result is a decrease in the amount of feed fluid, and consequently a decrease in the polymer and the resulting micro-: * · *: bubble mixing result. In this case, the pressure medium introduced from the aperture · .. * · '116 into the pressure medium cylinder 92 is to move the polymer and mixing fluid supply means 100 upwardly by the piston disc 106 so that the spacing between the cones 82 and 108 increases and the end of the mixing fluid supply high that · «· the feed fluid flow flushes any impurities or solids between the cones • ·: * through opening 84 into the process fluid flow pipe. Preferably, the rinsing time is about 1 to 6 seconds, after which 120 pressurized media is introduced from the opening 30 of the counter-30 end of the pressure medium cylinder 92 to the cylinder, whereby the piston disk 106 * ···: ** ·. push the feeders 100 back to the operating position.

** · P4132; Matula 10 1 1 8632

Figure 3 shows a preferred connection of the feed fluid 34 attached to the process fluid flow line 70 to the different pipelines. Polymer or polymer solution is fed to feeder 34 via pump 46, if necessary via a tube 48, which is prepared in a special container 44. The feeder 34 is further provided with a dispersion fluid for microflotation through one 144 and through tube 148, which also acts as feed fluid. The pressurized liquid or dispersion fluid obtained in a manner known per se is, for example, passed from a container 150 through a conduit 148 to a feeder 34, from where it is mixed and fed with the polymers to the process fluid flow tube 70. The dispersion fluid is preferably a process fluid, e.g. or clean water imported from outside the process.

To ensure mixing of the polymers and the dispersion liquid, the process liquid is fed via a feeder 34 together via 162 and a tube 166, together with the polymers and the dispersion liquid, a mixing liquid which may advantageously be and Untreated pro-> ai> can also be used as the mixing liquid. liquid or, if necessary, clean water. The process fluid flows, if necessary, by means of a pump 20 71 in a flow tube 70 to a microflotation or DAF basin 72. One or more feeders 34 attached to the process fluid flow tube 70 mix polymers and microbubbles formed from the dispersion liquid into the process fluid stream. These small microbubbles bind to the solid of the liquid to be treated, i.e. the process fluid, in the flow tube 70 or / and the microflot basin · 72. The impurities are transported to the surface of the microflot basin 72 by the lighter microbubble structures. The resulting surface slurry can be removed through pipe 76. The treated liquid flows out through conduit 74, whereupon, if necessary, a portion is pumped back to feeder 34 via pump 78 and conduit 166. ***. via tea 162 for use as a mixing fluid of the feeder 34.

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In addition to the arrangement of the flow tube 70 shown in Figure 3, in addition to the microflotation bath 72, the process fluid flow tube 70 may be located in the microflot P4132; The matrix 11 118632 also has a trough, for example, such that the end of the flow tube 70 is mounted at the bottom of the microflot pool 72 so that the process fluid flows downward perpendicular to the microflot pool 72. At least one feeder 34 is spaced or even that the flow jets fed from the feeder means 34 through the inlet opening to the process fluid flow tube 70 cover the entire cross-sectional area of the flow tube 70.

As can be seen from the foregoing, a novel and good mixing feeder has been developed for introducing the media required for microflotation into the process fluid. With reference to the foregoing, it should be noted that although some of the preferred uses of the feeder have been discussed above, it is possible to use it in other applications suitable for the feeder and thus the scope and scope of the invention are defined only by the appended claims.

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Claims (25)

A process for performing microflotation, in which process dispersion liquid and, if necessary, polymers are supplied with a process liquid, characterized in that said polymers are supplied with a high velocity process fluid flow substantially simultaneously with a feed liquid which enters the process liquid flow which dispenses liquid liquid. is formed in a manner known in the prior art, such that both the liquids are measured from their respective feed openings in a feed device to the said process fluid flow, and that the polymers are evenly distributed throughout the whole process liquid flow by means of a mixing liquid. Process according to claim 1, characterized in that said polymers and mixing liquid are supplied by at least two interconnected, ethereal flow paths to the process fluid flow. Process according to claim 1, characterized in that in addition to the polymer flow and the mixing liquid flow, a third flow consisting of dispersion liquid and which together with the polymer flow is mixed in the mixing liquid flow. 4. The method according to claim 1, characterized in that the process liquid • · · consists of some liquid to be purified by microflotation, whereby: ·: v. process liquid which is purified using • *! ··· is used as a mixing liquid. Microflotation, i.e. filtrate. • t «· · Process according to Claim 1, characterized in that the process liquid ·: ***: consists of some liquid which is to be purified by means of micro flotation, wherein · »* as mixed liquid is used as untreated process liquid. • · 30 • · *. Process according to claim 1, characterized in that the process liquid * ·. consists of some liquid to be purified by means of micro-flotation, whereby process fluid which is purified by micro-flotation is used as a dispersion liquid, ie. filtrate. Process according to Claim 1, characterized in that the process liquid 5 consists of some liquid to be purified by means of micro-flotation, whereby the dispersion liquid is used as untreated process liquid. Process according to Claim 1, characterized in that said process liquid is any liquid to be purified by means of micro flotation, and that the flow rate of the mixture of said polymers and liquids supplied to the liquid to be purified is at least five times that of the feed liquid compared to the process liquid. flow rate. Θ. Process according to Claim 1, characterized in that a feed device (34), in accelerating the flow rate of the feed liquid, is used in the addition of the dispersing liquid acting in said polymers and in supplying the mixture of said polymers and feed liquid. Process according to claim 1, characterized in that a feed device (34) which lowers the pressure of the feed liquid is used in the addition of the dispersion liquid acting as feed liquid in said polymers and in the application of the mixture of said polymers and «. * '* Feed liquid.: -V • · 11. A process according to claim 3, characterized in that said polymers and dispersion liquid are measured from the feed device (34) to said process liquid flow by means of the mixing liquid. * · «•« 12. Apparatus for supplying media needed for microflotation to a process fluid, which device comprises at least one feeding device arranged in conjunction with a process fluid flow channel, characterized in that: said feeding device (34) acts as a mixer having at least three inner feed openings (58,62,64,84,122) which open to the process fluid flow channel (70), of which said polymer is supplied to the first feed opening, the mixing liquid to the second the feed orifice and the dispersion liquid which also acts as a feed liquid to the third feed orifice. Device according to claim 12, characterized in that said feeding device (34) is provided with a tube (56) for said polymer. 10 Device according to claim 13, characterized in that said pipe (56) is tangential. Device according to claim 12, characterized in that said feeding device (34) is provided with a tube (144) for said feeding liquid, i. dispersion liquid. Device according to claim 15, characterized in that said pipe (144) is tangential. 20 Device according to Claim 12, characterized in that said feeding device (34) is provided with a pipe (162) for said [· · · · mixing liquid. Apparatus according to claim 12, characterized in that said feeding device (34) consists essentially of a hollow body (50, 80) provided with means (52, 54) for securing the tube ( 162) supplying ** · *: ***: mixing liquid and with feed openings (58, 62, 64, 84,122) for feeding ··· of said liquids into the process fluid flow. A * 30 • · • 19. Devices according to claim 18 , characterized in that a piece (60, 110) is arranged inside the body (50, 80) of the feeding device (34), with a section of the flow path through said body (50, 80) being reduced to increase the flow rate of the feeder (34). Device according to claims 13 and 19, characterized in that said tube 5 (56) opens into the piece (60,110). Apparatus according to claims 12 and 19, characterized in that the piece (60, 110) is provided with a feeder opening (62, 122) located within the feeder opening (64) for said mixing liquid. 10 Apparatus according to claim 18, characterized in that the piece (50, 80) is provided with a feed opening (64) for the polymer flow located inside the feeder opening (58, 84). Device according to claim 12, characterized in that the process liquid is any liquid to be purified by micro-flotation, wherein said feeding device (34) is attached to a conduit (70) leading to a micro-flotation funnel (72) so that said feeder opening ( 58, 84) opens into said conduit (70). Device according to claim 12, characterized in that the feeding devices (34) are arranged at regular intervals on the circumference of the conduit (70). • · ··· · * · • · · • ·! ·· *. 25. Device according to claim 12, characterized in that the liquid jets t · as measured from the feeding devices (34) via said feeder opening (58, 84) to the conduit (70) cover the total cross-section of the conduit (70). • •• I • · · • a «· * a a • · · • · a a a • a • a • · • + a • ·· • ·