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WO2014068185A1 - Procédé permettant d'empêcher le dépôt de tartre sur les surfaces d'un appareil de mélange à injection et appareil de mélange à injection - Google Patents

Procédé permettant d'empêcher le dépôt de tartre sur les surfaces d'un appareil de mélange à injection et appareil de mélange à injection Download PDF

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Publication number
WO2014068185A1
WO2014068185A1 PCT/FI2013/051022 FI2013051022W WO2014068185A1 WO 2014068185 A1 WO2014068185 A1 WO 2014068185A1 FI 2013051022 W FI2013051022 W FI 2013051022W WO 2014068185 A1 WO2014068185 A1 WO 2014068185A1
Authority
WO
WIPO (PCT)
Prior art keywords
casing
fluid
mixing apparatus
conduit
injection mixing
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.)
Ceased
Application number
PCT/FI2013/051022
Other languages
English (en)
Inventor
Jouni Matula
Jussi MATULA
Jari RÄSÄNEN
Karri TAHKOLA
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.)
Wetend Technologies Oy
Original Assignee
Wetend Technologies Oy
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 Wetend Technologies Oy filed Critical Wetend Technologies Oy
Publication of WO2014068185A1 publication Critical patent/WO2014068185A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
    • B05B7/00—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas
    • B05B7/02—Spray pistols; Apparatus for discharge
    • B05B7/04—Spray pistols; Apparatus for discharge with arrangements for mixing liquids or other fluent materials before discharge
    • B05B7/0408—Spray pistols; Apparatus for discharge with arrangements for mixing liquids or other fluent materials before discharge with arrangements for mixing two or more liquids
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/4602—Treatment of water, waste water, or sewage by electrochemical methods for prevention or elimination of deposits
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F25/30—Injector mixers
    • B01F25/31—Injector mixers in conduits or tubes through which the main component flows
    • B01F25/314—Injector mixers in conduits or tubes through which the main component flows wherein additional components are introduced at the circumference of the conduit
    • B01F25/3143—Injector mixers in conduits or tubes through which the main component flows wherein additional components are introduced at the circumference of the conduit characterised by the specific design of the injector
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J4/00—Feed or outlet devices; Feed or outlet control devices
    • B01J4/001—Feed or outlet devices as such, e.g. feeding tubes
    • B01J4/002—Nozzle-type elements
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B08—CLEANING
    • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
    • B08B17/00—Methods preventing fouling
    • B08B17/02—Preventing deposition of fouling or of dust
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F15/00—Other methods of preventing corrosion or incrustation
    • C23F15/005—Inhibiting incrustation
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H23/00—Processes or apparatus for adding material to the pulp or to the paper
    • D21H23/02—Processes or apparatus for adding material to the pulp or to the paper characterised by the manner in which substances are added
    • D21H23/04—Addition to the pulp; After-treatment of added substances in the pulp
    • D21H23/20—Apparatus therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J2219/00049—Controlling or regulating processes
    • B01J2219/00245—Avoiding undesirable reactions or side-effects
    • B01J2219/00247—Fouling of the reactor or the process equipment

Definitions

  • the present invention relates to a method of preventing scaling on surfaces of an injection mixing apparatus and an injection mixing apparatus.
  • the injection mixing apparatus of the present invention may be applied in any industry where there is a risk of formation of scaling on the surfaces of the injection mixing apparatus.
  • the injection mixing apparatus of the invention is especially applicable in pulp and paper industry, i.e. in wood processing industry.
  • Injection mixing apparatuses are used in various applications in different industries.
  • a part of the applications is, in a way, simple as the liquid or gas to be injected neither itself nor with any other liquid or gas it gets into contact with is able to form any chemical compounds or other particles that would tend to adhere to the surfaces of the mixing apparatus.
  • Another part of the applications is such that the gas or liquid to be injected forms scaling or other particles either alone or together with another injected gas, liquid or injection or mixing liquid, the scaling or particles adhering to the surfaces of the mixing apparatus and cause different kinds of problems.
  • the scaling may be formed the following manners are briefly discussed.
  • polymers when reacting rapidly with the anionic trash (pitch, for example) of the injection flow may form scaling that sticks to the surfaces of the nozzle part of the injection mixer.
  • a thin bio- or bacterial material film may be grown on the surfaces of the injection mixing apparatus.
  • lignin dissolved from the wood as well as some chemicals may also adhere to the surfaces of the injection mixer or any other surface/s nearby.
  • a hard shelllike calcium carbonate precipitation is formed on the surfaces of in-line PCC production devices.
  • resin has a strong tendency of forming scaling, especially in case of temperature changes.
  • the scaling has a number of negative effects on the mixing, i.e. effects relating to the runnability of the process, increased disruptions in the process and quality of the end product.
  • the scaling may have an influence on the flow characteristics of the mixing apparatus, i.e. the scaling may reduce the cross sectional flow area of the injection mixing apparatus, which may lead to reduction in the amount of chemical injected by the mixing apparatus, and result in changes in the properties of the end product.
  • Such reduction in the flow area may also have other effects on the mixing, i.e. making the mixing unequal, uneven or inhomogeneous
  • the scaling may block the injection flow entirely, or at least one or more injection openings at the nozzle part of the injection mixer.
  • the reduction in the cross sectional flow area results in higher pressure difference, which means increased energy required for pumping the desired injection flow.
  • the scaling may reduce the cross sectional flow area of the actual process pipe resulting in the reduction of volume flow in the process pipe, or causing at least possibly negative changes in the flow characteristics, i.e. turbulence, fluctuation etc. or increasing the energy needed for pumping the process liquid.
  • Such changes in the flow area may also have an effect on the mixing, i.e. making the mixing unequal, uneven or inhomogeneous.
  • the scaling that has formed on the surfaces of the injection mixing apparatus may from time to time loosen as substantially large particles from the surfaces, and proceed along with the flow up to the end product breaking the end product, reducing the quality of the end product, or at least increasing the reject material of the process if the particles are captured by the possible screens arranged in the process piping.
  • the injection mixing apparatus discussed in CA 2541528 may be used as an example of injection mixing apparatus the present invention is concerned about.
  • the above discussed injection mixing apparatus is composed of a feed conduit for a chemical, a first casing at least partially surrounding the chemical feed conduit, and a second casing at least partially surrounding the first casing and by means of which the injection mixing apparatus is attached to the wall of the process liquid flow pipe or to any wall of a chamber or cavity inside which the process liquid is contained.
  • the first casing is used for receiving mixing liquid and the second casing for receiving the feed/injection liquid.
  • the first casing comprises an outside wall, an open interior, and an inlet opening in communication with a first inlet duct for a so called mixing liquid, an opening via which the chemical feed conduit extends into the first casing, and one or more openings at an end opposite the opening for the chemical feed conduit.
  • the second casing comprises an outside wall, an open interior and three openings through the outside wall, i.e. an outlet opening that is, when the mixing apparatus is attached to the wall of the process liquid flow pipe, in flow communication with an opening in the wall of the process liquid flow pipe, an inlet opening in communication with a second inlet duct used normally for introducing so called injection or feed liquid into the mixing apparatus, and an opening, opposite to the outlet opening, via which the first casing extends into the second casing.
  • a prior art injection mixing apparatus has one opening at an end of the first casing for allowing the chemical feed conduit to pass the opening and extend outside the first casing for feeding a chemical into the process liquid chamber, cavity or flow pipe.
  • the injection mixing apparatus is, when in operation, attached to a wall of a chamber, a cavity or a flow pipe containing process liquid by means of a sleeve, the first end of which conforms to the outer surface of the process liquid chamber, cavity or flow pipe, and the second end having a flange or other communicating means communicating with a flange or other communicating means at an end of the second casing.
  • the injection mixing apparatus directly from its second casing to the wall of the process liquid chamber, cavity or flow duct, but such is considered a less attractive option.
  • injection mixing apparatus functions well as long as any combination of the injection liquid, mixing liquid, the chemical and the process liquid are not able to form any solid compounds that are prone to attach on the surfaces of the process equipment including the injection mixing apparatus.
  • the injection liquid, mixing liquid, and/or the process liquid sometimes the process liquid is used as the injection liquid and/or the mixing liquid
  • the process liquid very often contain solids or such chemicals that either together or together with the chemical/s to be injected into the process liquid are able to form scaling, there is a great risk that the scaling adheres to the injection mixing apparatus resulting in the problems discussed already above.
  • WO-A2-201 1 1 10745 discusses a method and a reactor for mixing one or more chemicals into a process liquid flow. Since the one or more chemicals are often such that tend to form precipitations or scaling on the surface of the reactor or flow pipe in which the process liquid flows, the reactor is provided with electrical means for keeping the surface of the reactor and possibly the structures therein clean.
  • the means is a first electrode arranged centrally in the flow pipe, a second electrode arranged in connection with the surface of the flow pipe, or the surface of the flow pipe itself acting as the second electrode, and an electrical circuit with a voltage source and a control unit arranged between and in connection with the electrodes.
  • the control unit is programmed to switch the polarity of the electrodes from time to time whereby both the direction of the movement of the ions and the pH at the surface of the electrodes changes resulting in dissolving of the possibly created scaling on the surface of an electrode.
  • an object of the present invention is to develop a method of preventing scaling on surfaces of an injection mixing apparatus that overcome at least some of the above discussed problems.
  • Another object of the present invention is to develop an electrical arrangement for preventing scaling in connection with an injection mixing apparatus such that no such additional means in the mixing apparatus is needed that could influence on the flow of the fluids in the mixing apparatus.
  • a further object of the invention is to utilize existing components of the injection mixing apparatus as the electrodes of an electric circuit so that the injection mixing apparatus needs to be provided with only the necessary electrical insulations and connections to a voltage source, i.e. components outside of the actual flow channels within the injection mixing apparatus.
  • At least one object of the present invention is fulfilled by a method of preventing scaling on surfaces of an injection mixing apparatus, the injection mixing apparatus comprising a conduit for a first fluid and at least one casing, the conduit for the first fluid being positioned centrally within the at least one casing and having a first end extending outside the at least one casing and the conduit for the first fluid being connected to a fluid source, the injection mixing apparatus, when in use, being attached to a wall of a process liquid flow pipe, the method comprising providing the injection mixing apparatus with means for preventing scaling on surfaces of the injection mixing apparatus.
  • a further feature of the present invention is the steps of electrically insulating the conduit for the first fluid from the at least one casing and the source of the first fluid, electrically insulating at least the at least one casing from the fluid source and the process liquid flow pipe, coupling the conduit for the first fluid to a terminal of an electrical circuit, coupling the at least one casing to another terminal of an electrical circuit, and changing the polarity of the electrical circuit from time to time for changing the pH at surfaces of the conduit for a first fluid and the at least one casing.
  • an injection mixing apparatus comprising a conduit for a first fluid and at least one casing, the conduit for the first fluid being positioned centrally within the at least one casing and having a first end extending through the at least one casing and the conduit for the first fluid being connected to a fluid source, the injection mixing apparatus, when in use, being attached to a wall of a process liquid flow pipe, wherein the injection mixing apparatus is provided with means for preventing scaling on surfaces of the injection mixing apparatus.
  • a further feature of the present invention is an electrical circuit coupled in electrical communication with such surfaces of the injection mixing apparatus that tend to collect scaling, wherein such surfaces are electrically insulated from one another.
  • Figure 1 illustrates a prior art injection mixing apparatus
  • Figure 2 illustrates an injection mixing apparatus in accordance with a first preferred embodiment of the present invention
  • Figure 3 illustrates an injection mixing apparatus in accordance with a second preferred embodiment of the present invention
  • Figure 4 illustrates an injection mixing apparatus in accordance with a third preferred embodiment of the present invention
  • Figure 5 illustrates an injection mixing apparatus in accordance with a fourth preferred embodiment of the present invention.
  • Figure 6 illustrates the injection mixing apparatus of Figure 3 coupled to an electrical circuit for maintaining the surfaces of the injection mixing apparatus clean.
  • FIG. 1 illustrates a prior art injection mixing apparatus 10.
  • the injection mixing apparatus 10 comprises a conduit 6 for feeding a chemical into the injection mixing apparatus 10, a first casing 2, and a second casing 4.
  • the first and the second casings are fastened to each other by means of, for instance, bolts 8.
  • the injection mixing apparatus 10 is fastened to the wall 12 of the process liquid flow pipe 14 by its first casing 2, for instance, by means of an intermediate sleeve 16.
  • the first casing 2 has an inlet duct 18 for a second fluid, i.e.
  • an injection or feeding liquid which may be either clean water or almost any non-clean liquid, or the process liquid itself that may be introduced into the process liquid, and at its first end 20 an outlet 22 via which the injection liquid is introduced (first into the sleeve 16, and then) into the process liquid flow pipe 14.
  • the opposite end, i.e. the second end 24 of the first casing 2 is provided with a preferably round opening 26 through which the second casing 4 extends into the first casing 2.
  • the first or inner end 28 of the second casing 4 extends out of the first end 20 of the first casing 2 inside the sleeve 16 such that the flow path (functions as an extension of the outlet 22) of the second fluid or the injection liquid between the sleeve 16 and the first end 28 of the second casing 4 is preferably annular.
  • the second or outer end 30 of the second casing 4 is provided with an inlet 32 for a so called third fluid, so called mixing liquid, and a preferably axial opening 34 for the conduit 6 for a first fluid, most often a chemical.
  • the chemical conduit 6 extends preferably axially though the second casing 4 leaving an annular flow passage between the conduit 6 and the second casing 4 for the second fluid, i.e. the mixing liquid.
  • the first end 36 of the chemical conduit 6 is located within the first end 28 of the second casing 4.
  • the chemical conduit 6 is connected at its second end 38 farther away from the process liquid flow pipe 14 to a source of the chemical.
  • the first or inner end 28 of the second casing 4 is located at about the level of the wall 12 of the process liquid flow pipe 14. However, the position of the second casing 4 may be adjusted by means of its fastening bolts 8 in its longitudinal direction so that the first or inner end 28 thereof may be left within the first casing 2, within the sleeve 16 or extend inside the process liquid flow pipe 14.
  • a coating of a certain material may also be used to prevent the scaling.
  • the coating material is selected such that the substances or chemicals forming the scaling are not able to adhere to the coating.
  • the coating may be, for instance, rubber, Teflon or a nano surface coating.
  • Figure 2 illustrates a novel injection mixing apparatus 40, which differs from the prior art injection mixing apparatus at the tip part or the first end 44 of the second casing 42.
  • the parts of the injection mixing apparatus that are the same as in the prior art mixing apparatus of Fig. 1 have maintained the same reference numerals, whereas the parts that have changed have been renumbered.
  • the second casing 42 of the injection mixing apparatus 40 has a first or inner end 44 provided with a cap 46 having a central opening 48 for a conduit 50 for the first fluid, for instance the first chemical.
  • the first end 52 of the conduit 50 for the first fluid extends through the cap 46 into the process liquid flow pipe 14.
  • the first end 52 may just extend through the cap 46, i.e. open immediately to the level of the cap, or the first end may extend deeper in the process liquid flow pipe, as shown in Figures 3 and 4.
  • the cap 46 is provided with holes 54 for injecting third fluid, for instance a mixing liquid and/or a second chemical or their mixture in more or less radial direction (in view of the second casing 42) into the annular flow path between the sleeve 16 and the second casing 42, in other words into an annular or fan-shaped jet of second fluid, i.e. injection liquid entering the flow pipe 14 from the annular flow path between the second casing 42 and the sleeve 16.
  • the concentration of at least one chemical at the tip area of the injection mixer is high, the chemical environment changes significantly such that the speed of formation of the calcium carbonate is high. And as the calcium carbonate has a tendency of adhering to all kinds of solids, including solid surfaces, there is a high risk that the injection holes 54 at the cap and corresponding hole/s at the first end 52 of the conduit 50 are gradually clogged or at least throttled by the scaling. Such would result in the reduction of the added chemical and the reduction in the quality of the end product.
  • the injection mixing apparatus 40 is provided with means (discussed in more detail in connection with Figure 6) changing the polarity of an electrical circuit between the second casing 42 and the conduit 50 for the first fluid.
  • the central opening 48 in the cap is provided with an electrical insulation 56.
  • the opening 34 at the opposite or second end 30 of the second casing 42 is provided with an electrical insulation 58, so that the conduit 50 for the first fluid and the second casing 42 may be connected to opposite (plus and minus) terminals of an electrical cleaning system.
  • the opening 26 at the second end 24 of the first casing 2 is provided with an electrical insulation 60 so that the first casing 2, the sleeve 16 and the process liquid flow pipe remain non-electrical components of the system.
  • all the fluid connections of the electrical components (here the second casing and the conduit for the first fluid) of the mixing apparatus have to be insulated from their respective fluid sources.
  • the conduit 50 for the first fluid has to be insulated from the source of the first fluid and the conduit 32 for the third fluid from the source of third fluid.
  • the attachment connecting the first casing 2 with the second casing 42 has to be electrically insulated or made of non-conducting materials.
  • the bolts 8 may be manufactured of non-conductive material.
  • the conduit 50 for the first fluid and the second casing 42 may be connected to opposite (plus and minus) terminals of an electrical cleaning system, which prevents the chemicals or the reaction products from adhering on the surfaces of the injection mixing apparatus electrochemically.
  • the conduit 50 for the first fluid functions as one electrode and the second casing 42 as another electrode.
  • one electrode forms a cathode and the other anode.
  • the existence of electric current changes the pH in the liquid (water) layer on the electrode surfaces such that the pH at the anode is lowered and, correspondingly, the pH at the cathode is increased.
  • the pH in the liquid layer close to the surface of the conduit 50 for the first fluid gets lower, whereby the calcium carbonate dissolves from the electrode surface to the liquid phase, and the electrode surface gets clean.
  • the anode i.e. the cap surface collects the calcium carbonate crystals.
  • the polarity of the electrical circuit may again be changed.
  • Figure 3 illustrates a second preferred embodiment of the present invention.
  • an injection mixing apparatus similar to that discussed in Figure 2 is used as the starting point. Therefore, the same reference numerals are used for the parts or components having the same structure and function. Also the types of fluid introduced into the mixing apparatus are the same.
  • the main difference between the embodiments of Figures 2 and 3 can be seen in the way the electrical insulations have been arranged. The main difference is that in the embodiment of Figure 2 the first casing 2 was electrically insulated from the second casing 42, whereas in the embodiment of Figure 3 both the first casing 2 and the second casing 42 form one electrode and the conduit 50 for the first fluid another electrode.
  • the conduit 50 for the first fluid is insulated from the second casing 42 by means of electrical insulators 56 and 58, just like Figure 2 teaches. But since the first and the second casings are not insulated from one another, the first casing 2 has to be electrically insulated from the wall 12 of the process liquid flow pipe 14. Such has, for instance, been performed by manufacturing the sleeve 62 used for connecting the injection mixing apparatus 40 to the wall 12 of the process liquid flow pipe 14 of an electrically non-conductive material. Naturally, fluid sources, i.e. the sources of the chemical/s, the mixing liquid and the feed or injection liquid are electrically insulated from the injection mixing apparatus 40. As yet another difference, which was already discussed in connection with Figure 2, is the length of the conduit 50 for the first chemical. Now here the first end 52' of the conduit extends deeper in the process liquid flow pipe 14.
  • FIG. 4 illustrates an injection mixing apparatus in accordance with a third preferred embodiment of the present invention.
  • the injection mixing apparatus 70 of Figure 4 comprises a conduit 50 for a first fluid, for instance a first chemical, a third casing 72 with an inlet 74 for a fourth fluid, for instance a third chemical or a mixing liquid or their mixture, a second casing 76 with an inlet 78 for a third fluid, for instance a mixing liquid or a second chemical or their mixture, and a first casing 80 with an inlet 82 for a second fluid, for instance a feed or injection liquid.
  • the first, second and third casings are fastened to each other by means of, for instance, bolts 85.
  • the injection mixing apparatus 70 is fastened to the wall 12 of the process liquid flow pipe 14 by its first casing 80, for instance, by means of an intermediate sleeve 16.
  • the first casing 80 has, in addition to the inlet 82 for the second fluid, which may be either clean water or almost any non-clean liquid that may be introduced into the process liquid, including the process liquid itself, an outlet 84 via which the second fluid is introduced into the sleeve 16 and further to the process liquid flow pipe 14.
  • the opposite end, i.e. the second end 86 of the first casing 80 is provided with a preferably round opening 88 via which the second casing 76 extends into the first casing 80.
  • the first or inner end 90 of the second casing 76 extends through the first casing 80 down to the sleeve 16 such that the outlet 84 and the flow path of the second fluid between the sleeve 16 and the first end 90 of the second casing 76 is preferably annular.
  • the inner or first end 90 of the second casing 76 terminates preferably within the sleeve 16 though it may extend up to the level wall 12 of the flow pipe 14 or sometimes even further.
  • the longitudinal position of the second casing 42 was, optionally, adjustable within the first casing 2. The same applies here, too.
  • the position of the first end 90 of the second casing 76 may be longitudinally adjusted, if desired, between the conical part or the first end 92 of the first casing 80 and the inside of the process liquid flow pipe 14.
  • the longitudinal, i.e. axial position of the third casing 72 is, preferably but not necessarily, adjustable, too. It means that, for instance, the position of the third casing 72 within the second casing 76 may be adjusted.
  • the second or outer end 94 of the second casing 76 is provided with an inlet 78 for the second fluid (the mixing liquid or the second chemical or their mixture), and a preferably axial opening 96 for the third casing 72.
  • the third casing 72 comprises a casing body 98 and a conduit 100 for the fourth fluid (the third chemical or the mixing liquid or their mixture).
  • the casing body 98 has an inlet 74 for the fourth fluid (the third chemical or the mixing liquid or their mixture), an outlet opening 102 communicating with the conduit 100 for the fourth fluid, and an opening 104 for a conduit 50 for the first fluid, for instance the first chemical.
  • the conduit 100 for the fourth fluid extends preferably axially though the second casing 76 leaving an annular flow passage for the third fluid between the conduit 100 for the fourth fluid and the second casing 76.
  • the first or inner end 90 of the second casing 76 and the conduit 100 for the fourth fluid leave an annular outlet opening 106 via which the third fluid is introduced into the flow of the second fluid.
  • the conduit 100 for the fourth fluid terminates to a cap 108, which is provided with a central opening 1 10 via which the conduit 50 for the first fluid passes into the flow pipe 14.
  • the cap 108 is provided with holes 1 12 for injecting the fourth fluid into the annular or fan-shaped jet of the third fluid and the second fluid entering the flow pipe 14 along the annular passage between the conduit 100 for the fourth fluid and the sleeve 16.
  • This kind of an injection mixing apparatus may also be provided with electrical insulations to facilitate the cleaning of the surfaces of the cap 108 and the first end 1 14 of the conduit 50 for the first fluid.
  • an insulation 1 16 is arranged in the opening 1 10 between the conduit 50 and the cap 108 at the first end 1 18 of the conduit 100 for the fourth fluid, an insulation 120 in the opening 96 between the conduit 100 for the fourth fluid and the second casing 76, and an insulation 122 in the opening 104 between the third casing 72 and the conduit 50 for the first fluid.
  • the various fluid conduits have to be insulated from their fluid sources, i.e.
  • the conduit 50 for the first fluid has to be insulated from its source, for instance from the chemical source, and the conduit 74 for the fourth fluid from its source.
  • the attachment connecting the third casing 72 with the second casing 76 has to be electrically insulated or made of non-conducting materials.
  • the bolts 85 may be manufactured of non-conductive material.
  • the above disclosed injection mixing apparatus for two (or more) chemicals may, as an alternative to the one shown in Figure 4, be provided with a similar electrical insulation as discussed in connection with Figure 3.
  • the insulation 120 between the second casing 76 and the conduit 100 for the fourth fluid may be, in a way, transferred to the sleeve 16, i.e. the sleeve may be manufactured of a non-conductive material.
  • the main parts in view of cleaning the mixing apparatus i.e. the conduit 50 for the first fluid and the conduit 100 for the fourth fluid may still be coupled to opposite (plus and minus) terminals of the electrical circuit, and the parts kept clean.
  • This kind of an insulation naturally precludes that all fluid conduits or ducts introducing a chemical, a mixing liquid and a feeding/injection liquid into the injection mixing apparatus have to be also electrically insulated from their sources.
  • Figure 5 illustrates a fourth preferred embodiment of the present invention.
  • the injection mixing apparatus 140 is of somewhat simpler construction than those of the earlier embodiments, i.e. the injection mixing apparatus 140 of Figure 5 has a conduit 142 for the first fluid and a (first) casing 144 for the second fluid, whereby the second casing utilized in the earlier embodiments is missing.
  • the injection mixing apparatus 140 is fastened from its first casing 144 to the wall 12 of the process liquid flow pipe.
  • the conduit 142 for the first fluid forms one electrode and the first casing 144 for the second fluid another electrode.
  • conduit 142 for the first fluid is insulated from the casing 144 by means of electrical insulator 146.
  • the casing 144 has been insulated from the wall 12 of the process liquid flow pipe by means of an insulator sleeve 148, manufactured of an electrically non-conductive material and by means of which the mixing apparatus 140 is actually fastened to the wall 12 of the process liquid flow pipe.
  • fluid sources i.e. the sources of the chemical/s, and the feed or injection liquid (conduit 142 introducing the feed/injection liquid into the casing 144) are electrically insulated from the injection mixing apparatus 140.
  • Figure 6 discusses in more detail the electrical circuit and the operation of the system discussed in connection with the earlier Figures 2 - 5.
  • the electrical means for preventing scaling on the surfaces of an injection mixing apparatus shown, as an example of the four earlier discussed embodiments, in Figure 3 comprise a control unit (CU), which is coupled by means of its plus and minus terminals to the conduit 50 for the first fluid, normally for the chemical, and, in this case, to the second casing 42, though also the first casing 2 is an option since the first and second casings are not insulated from one another in this particular embodiment.
  • CU control unit
  • a certain pH (acidic or alkaline) is formed in the nearhood of the surface of the conduit 50 for the first fluid and a corresponding opposite pH (alkaline or acidic) in the nearhood of the surface of the second casing 42.
  • the pH value attracts some substances to precipitate on the surface of the first end 52 of the conduit 50 for the first fluid and some other substances on the surface of the first end 44 of the second casing 42, and simultaneously the pH is able to make some other substances dissolve and thus loosen from those surfaces.
  • the simplest control method is to program the control unit to change the polarity of the electrical circuit by means of a timer at certain intervals (from fractions of a second to seconds, minutes or hours) for keeping both electrodes clean.
  • Another way to control the polarity changes is to use a control impulse from the process. It is, for example, possible to monitor the voltage difference between the cathode and the anode (illustrated by means of a voltage meter V), whereby a certain increase in the voltage in practice means a precipitation layer of a certain thickness (the layer acting as isolation).
  • the control unit may be calibrated to change the polarity of the electrical circuit at a certain potential difference.
  • the control system switches the polarity back to the original state.
  • the injection mixing apparatus since the scaling-related problem is limited to such surfaces of the injection mixing apparatus that are in communication with at least one of the chemicals injected by the mixing apparatus and either one of the fluids being injected or the process liquid or both, the surfaces are at a close proximity of the process liquid flow duct, possibly within the process liquid flow duct. Also, it has to be understood that the injection mixing apparatus itself should have those two different surfaces on which the scaling may precipitate. As long as such is the case the insulation of the two different surfaces is quite simple, as shown by the above examples. If the other surface, on which the scaling tends to collect, were the wall of the process liquid flow duct, the wall should form one electrode of the electrical circuit. Since such is not desired, unless a certain length of the process liquid flow duct were to be insulated electrically from the rest of the flow duct, the two different surfaces should be found from the injection mixing apparatus.
  • Figures 2 - 5 illustrate a few exemplary embodiments of the structures of the applicable injection mixing apparatus.
  • the basic principle of the present invention is that the two elements of the injection mixing apparatus extending closest to the process liquid flow pipe should be electrically insulated from one another, and also from the fluid sources including sources for the injection liquid and the mixing liquid (if used), and possibly one or more chemical sources, and from the process liquid flow pipe.
  • the radially outer element is directly or indirectly insulated.
  • Figure 2 teaches a direct insulation 60 of the second casing 42 from the first casing 2 surrounding it and Figure 3 an indirect insulation 62 of the second casing 42 from the process liquid flow pipe 14.
  • terminals would be coupled to the chemical conduit 50 and to the first casing 42. Likewise in the embodiment of Figure 5, the terminals would be coupled to the conduit 142 and the (first) casing 144.
  • Figure 6 illustrates as a preferred feature of the present invention a reference electrode 134, which is arranged in a close proximity of the injection mixer 40.
  • the reference electrode may be attached to the injection mixer itself, preferably to such a part that is located within the reactor or flow pipe, or to a wall of the flow pipe or reactor in the nearhood of the injection mixer.
  • the purpose of the reference electrode 134 is to sense the surface charge at its position, i.e. the polarity of its surface, or, in other words, the chemical environment at the tip area of the injection mixer.
  • the information it gives may be used either manually when adjusting the operating parameters (for instance, the voltage and the cycle time) of the control unit and the circuit it is connected to or automatically for giving instructions to the control unit to change its operating parameters if the chemical environment at the tip area of the injection mixer appears to be changing.
  • the reference electrode 134 may be used in connection with any one of the embodiments discussed above as well as all the variations of the present invention covered by the appended claims.
  • the invention may be applied anywhere chemicals need to be fed and mixed into a process medium flow evenly and in precise amounts.
  • the field of application and the scope of protection of the invention are defined by the appended patent claims, only.
  • the word "chemical” is understood in a broad sense, i.e. it covers each and every additive, treatment agent, filler, pigment etc. being introduced in the process liquid for treating the process liquid or for changing its properties or the properties of an intermediate or end product.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Environmental & Geological Engineering (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Water Supply & Treatment (AREA)
  • Metallurgy (AREA)
  • Mechanical Engineering (AREA)
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  • Paper (AREA)
  • Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)

Abstract

La présente invention concerne un procédé permettant d'empêcher le dépôt de tartre sur les surfaces d'un appareil de mélange à injection et un appareil de mélange à injection (40, 70, 140). L'appareil de mélange à injection selon l'invention peut notamment être appliqué à l'industrie de la pâte à papier et du papier, c'est-à-dire à l'industrie de la transformation du bois. L'appareil de mélange à injection (40, 70, 140) selon la présente invention comprend un moyen électrique (30) permettant d'empêcher le dépôt de tartre sur ses surfaces.
PCT/FI2013/051022 2012-10-30 2013-10-29 Procédé permettant d'empêcher le dépôt de tartre sur les surfaces d'un appareil de mélange à injection et appareil de mélange à injection Ceased WO2014068185A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI20126128 2012-10-30
FI20126128A FI20126128A7 (fi) 2012-10-30 2012-10-30 Menetelmä saostumisen estämiseksi injektiosekoitinlaitteen pinnoille ja injektiosekoitinlaite

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WO2014068185A1 true WO2014068185A1 (fr) 2014-05-08

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20150049575A1 (en) * 2012-03-26 2015-02-19 Wetend Technolgies Oy Method and an apparatus for mixing chemicals having opposite electric charges into a process liquid flow
WO2017098083A1 (fr) 2015-12-09 2017-06-15 Outotec (Finland) Oy Appareil de mélange et agencement pour l'introduction d'un premier liquide, d'un deuxième liquide et d'un troisième liquide dans un écoulement de liquide de traitement qui s'écoule dans une section de canalisation à écoulement linéaire

Families Citing this family (1)

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Publication number Priority date Publication date Assignee Title
CN106698604B (zh) * 2017-01-17 2020-07-24 成都理工大学 一种可拆卸便携式快速处理低浓度氨氮污水的方法

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Publication number Priority date Publication date Assignee Title
US20010050881A1 (en) * 1999-09-20 2001-12-13 Depaoli David W. Continuous flow, electrohydrodynamic micromixing apparatus and methods
CA2541528A1 (fr) 2003-10-08 2005-04-14 Wetend Technologies Oy Procede et appareil permettant d'alimenter un agent chimique dans un ecoulement de liquide
WO2011110745A2 (fr) 2010-03-10 2011-09-15 Wetend Technologies Oy Procédé et réacteur pour le mélange d'un ou plusieurs produits chimiques dans un écoulement de liquide de traitement
WO2012047108A1 (fr) * 2010-10-07 2012-04-12 Stichting Wetsus Centre Of Excellence For Sustainable Water Technology Procédé et dispositif permettant de lutter contre la salissure biologique

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20010050881A1 (en) * 1999-09-20 2001-12-13 Depaoli David W. Continuous flow, electrohydrodynamic micromixing apparatus and methods
CA2541528A1 (fr) 2003-10-08 2005-04-14 Wetend Technologies Oy Procede et appareil permettant d'alimenter un agent chimique dans un ecoulement de liquide
WO2011110745A2 (fr) 2010-03-10 2011-09-15 Wetend Technologies Oy Procédé et réacteur pour le mélange d'un ou plusieurs produits chimiques dans un écoulement de liquide de traitement
WO2012047108A1 (fr) * 2010-10-07 2012-04-12 Stichting Wetsus Centre Of Excellence For Sustainable Water Technology Procédé et dispositif permettant de lutter contre la salissure biologique

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20150049575A1 (en) * 2012-03-26 2015-02-19 Wetend Technolgies Oy Method and an apparatus for mixing chemicals having opposite electric charges into a process liquid flow
WO2017098083A1 (fr) 2015-12-09 2017-06-15 Outotec (Finland) Oy Appareil de mélange et agencement pour l'introduction d'un premier liquide, d'un deuxième liquide et d'un troisième liquide dans un écoulement de liquide de traitement qui s'écoule dans une section de canalisation à écoulement linéaire
US10155206B1 (en) 2015-12-09 2018-12-18 Outotec (Finland) Oy Mixing apparatus and arrangement for introducing a first liquid, a second liquid, and a third liquid into a process liquid flow which is flowing in a linear flow duct section

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FI20126128A7 (fi) 2014-05-01

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