CA1043147A - Method and device for distribution and mixing-in of gas and/or liquid in pulp suspensions of high concentration - Google Patents
Method and device for distribution and mixing-in of gas and/or liquid in pulp suspensions of high concentrationInfo
- Publication number
- CA1043147A CA1043147A CA247,730A CA247730A CA1043147A CA 1043147 A CA1043147 A CA 1043147A CA 247730 A CA247730 A CA 247730A CA 1043147 A CA1043147 A CA 1043147A
- Authority
- CA
- Canada
- Prior art keywords
- pulp
- inlet
- treatment
- chlorine
- 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.)
- Expired
Links
Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
- D21C9/10—Bleaching ; Apparatus therefor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
- B01F23/40—Mixing liquids with liquids; Emulsifying
- B01F23/45—Mixing liquids with liquids; Emulsifying using flow mixing
- B01F23/454—Mixing liquids with liquids; Emulsifying using flow mixing by injecting a mixture of liquid and gas
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
- B01F23/20—Mixing gases with liquids
- B01F23/23—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids
- B01F23/237—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids characterised by the physical or chemical properties of gases or vapours introduced in the liquid media
- B01F23/2376—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids characterised by the physical or chemical properties of gases or vapours introduced in the liquid media characterised by the gas being introduced
- B01F23/23763—Chlorine or chlorine containing gases
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
- B01F23/40—Mixing liquids with liquids; Emulsifying
- B01F23/43—Mixing liquids with liquids; Emulsifying using driven stirrers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
- B01F23/50—Mixing liquids with solids
- B01F23/53—Mixing liquids with solids using driven stirrers
-
- 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
- B01F25/10—Mixing by creating a vortex flow, e.g. by tangential introduction of flow components
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
- B01F23/50—Mixing liquids with solids
- B01F23/56—Mixing liquids with solids by introducing solids in liquids, e.g. dispersing or dissolving
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F27/00—Mixers with rotary stirring devices in fixed receptacles; Kneaders
- B01F27/05—Stirrers
- B01F27/11—Stirrers characterised by the configuration of the stirrers
- B01F27/112—Stirrers characterised by the configuration of the stirrers with arms, paddles, vanes or blades
- B01F27/1125—Stirrers characterised by the configuration of the stirrers with arms, paddles, vanes or blades with vanes or blades extending parallel or oblique to the stirrer axis
Abstract
ABSTRACT OF THE DISCLOSURE
A method and device are provided for mixing and distributing pulp of relatively high concentration with one or more treatment media.
The device includes a housing formed with adjacent cylindrical and conical portions. Diposed in the cylindrical portion is a series of rotatable blades and the periphery of the cylindrical portion is provided with a pulp inlet and at least one treatment medium inlet. Pulp and treatment medium are supplied continuously and rotate and mix in the cylindrical portion before being pushed through the conical portion and out of a central outlet therein. More efficient and even mixing is obtained even at relatively high pulp concentrations, leading to operational economis.
A method and device are provided for mixing and distributing pulp of relatively high concentration with one or more treatment media.
The device includes a housing formed with adjacent cylindrical and conical portions. Diposed in the cylindrical portion is a series of rotatable blades and the periphery of the cylindrical portion is provided with a pulp inlet and at least one treatment medium inlet. Pulp and treatment medium are supplied continuously and rotate and mix in the cylindrical portion before being pushed through the conical portion and out of a central outlet therein. More efficient and even mixing is obtained even at relatively high pulp concentrations, leading to operational economis.
Description
1~143~47 The invention relates to a method and a device for distributingand mixing pulp, particularly in the treatment of cellulose pulp, in which pulp of relatively high concentration, preferably above 5%, during its processing must be supplied with and mixed with one or more media necessary for treatment of the pulp.
It is desirable that such distribution and mixing-in should be as effective as possible, i.e. that the medium or media in the first case are distributed as evenly as possible in the pulp suspension and in the second case the evenness is secured through a mixing of the pulp suspension so that even a relatively small quantity of treatment medium is distributed evenly in and around each individual particle or fiber of the pulp suspension.
The effectiveness of such distribution and mixing is dependent on many factors, such as e.g. the pulp concentration in relation to the quantity of liquid or gas which is to be added, the solubility of the added liquid or gas in the suspension liquid and the reaction speed of the added media with the particles of the pulp suspension. Generally it can be said that the higher the concentration of solids or fibers in the pulp suspension, in other words the less liquid present in the suspension, the more difficult it is to mix-in treatment media so that they are evenly distributed in the suspension. Generally it can also be said that the faster the added media react with the pulp, the more important it is that the media are distributed and mixed-in as quickly and as evenly as possible. such a case occurs e.g.
during treatment of pulp with chlorine in connection with bleaching of the pulp. Chlorine undergoes a specially quick initial reaction with pulp and in order not to dilute the pulp with an unwanted quantity of liquid, chlorine is most often added as gas dispersed in a relatively small quantity of liquid which, however, in turn means that problems can easily arise as to distribution and mixing-in of this relatively small quantity. An object with the invention is therefore to attempt to solve this problem and also the problems which arise when the pulp suspension has a relatively high concentration of fibers, .~
~043~47 preferably above 5%, e.g. from about 8 to 12% or about 10%.
In the pulp industry, the bleaching of pulp with chlorine has hitherto preferably been carried out at 3-4% pulp solids concentration mainly due to mechanical difficulties with mixing-in and distribution, apa~t from gas phase-chlorination in which case the concentration can be in the range 20-50%. Since in other treatment stages of industrial bleach plants, the - pulp concentration is normally kept around 10%, it is desirable also to be able to carry out the chlorine treatment at this same concentration so that one can use uniform equipment in the bleach plant. This has special import-ance for the washing apparatus which is used between the treatment stagesO
Since the treatment with chlorine most often takes place in the beginning of the bleach plant and the pulp therefore must be thickened to about 10%
concentration before the pulp goes on to the next treatment stage, savings and simplifications can be obtained if this first chlorine treatment also can take place at about the same high concentration.
. . .
One aspect of the present invention provides a method for continuously distributing and mixing pulp of relatively high concentration with a treatment liquid or treatment gas, wherein the pulp is continuously led into a device in which the pulp is given a fast circular movement inside a concentric limited surface through which the treatment medium is peripherally and continuously added to contact the pulp in a predominantly even layer distributed over outer moving pulp layer, and thereafter effecting mixing the contact pulp with the distributed medium by changing the circular move-ment of the pulp to a helical movement of decreasing diameter towards an outlet from which the treated pulp is continuously removedO
Another aspect of the invention provides a device for continuous distribution and mixing of pulp of relatively high concentration with at least one treatment liquid or treatment gas, which comprises a closed housing provided with an inlet and outlet for pulp and an inlet for treatment media, and a rotor with blades or wings 1043~7 fastened to one set of arms extending from a rotatably driven shaft, the housing having a cylindrical part inside which the blades are concentrically located close to the cylindrical part, which cylindrical part abuts on one side with a conical part which reduces in diameter to a concentric pulp outlet and on the other side abuts a wall through the centre of which the rotor shaft passes, both the pulp inlet and the treatment media inlet being arranged on the cylindrical part of the housing.
Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings in which:
Figure 1 is a side sectional view of a mixing device;
Figure 2 is a cross-section taken along line A-A of Figure l; and Figure 3 shows a side elevation of two devices coupled together.
The device of Figure 1 consists of a concentric housing 1, in which a rotor 2 can rotate by means of a motor (not shown). The housing 1 includes a cylindrical part 3, a conical front part 4, and a conical back part 5. The rotor 2 has a hub 6, which is fastened to a shaft 7. Transport blades or wings 9 are fastened to the hub by means of a number of arms 8.
The shaft is supported in a bearing housing 10 and sealed against the outside by means of a suitable mechanical sealing or packing box 11. The bearing housing 10 is fastened to the housing 1 by means of supporting bars 12.
With reference to Figure 2 a connection piece 20 is shown through which pulp flows into the device and a connection piece 21 is provided for addition of chemicals. Both connection pieces 20 and 21 are arranged in the cylindrical part 3 of the housing and can be disposed tangentially such as shown for the connection 20. Relative to the direction of the connection 20 the rotor has a rotation direction as shown by arrow 22. After treatment in the device the pulp flows out through opening 13 in the conical front part 4.
The device according to Figures 1 and 2 operates in the following manner. Pulp of a certain concentration, e.g. 10-12%, is added to the device in a continuous flow through the connection 20. The rotor which is rotating with a definite, suitable speed of revolution, causes the incoming pulp to 1~)43~47 rotate intensively. The housing 1 is at all times filled with pulp which later leaves the device through the outlet 13. The rotor wings 9 are made so that the incoming pulp already at the entrance into the inner part of the device is caused to rotate inside the cylindrical part 3 against which the incoming pulp will be thrown due to centrifugal force. A liquid treatment medium or e.g. chlorine gas dispersed in a relatively small quantity of liquid is added through the connection 21. This added liquid quantity which is added peripherally in the cylindrical part 3 will be distributed as a layer ; on top of the pulp fed in just previously and which is rotating as a layer against the cylindrical surface. When the pulp layer with the added chemical layer has rotated around the inner part of the housing and returned back to the inlet 20, a new layer of pulp will add on outside the first one and a new layer of chemicals will add on outside the last mentioned pulp layer. In that way repeated layers will be built up which are forced to move inwardly and outwardly towards the outlet 13 due to the double conical shape of the housing. If it is desired to distribute the chemicals or to add more chemicals, more connections 21 can be arranged successively on the cylindrical part 3.
In practical trials it has been shown that the pulp during movement inside the housing from the cylindrical part 3 out through the conical part 4 towards the outlet 13 undergoes intensive mixing which mainly can be credited the contraction which is taking place in the conical converging zone at the same time as the friction against the housing inner walls slows down the speed of rotation, while the rotation in the central parts of the housing continues since here is being built up an intensive whirling current with inwardly increasing speed of revolution. ~ue to such conditions dis-placements between the pulp layers will take place and the intended mixing - is achieved.
In Figure 3 two, in principle, identical devices are coupled together in a special manner which has proved to be very advantageous during practical trials. The devices have been coupled together with inlet against ~1_ 1~43~47 inlet, which in other words means that inlet 32 and outlet 33 of the first device 30 have opposite functions since the pulp is added to the conical part of the device and leaves this through a tangential outlet which is coupled together with the normal tangential inlet of the other device. It is obvious-ly also possible to couple the devices in series in a more conventional manner in that the pulp is pumped into the tangential inlet of the first de-vice and leaves this one through its conical part which then is coupled to the tangential inlet of the next device in which the pulp leaves through the conical outlet. Depending upon the number of chemical treatments wanted, obviously more devices can be coupled together in the first or last mentioned manner. A treatment which has recently become very common is sequence-chlorination by which is meant that a chlorine-containing medium, e.g.
chlorine dioxide, of certain quantity is added to the pulp before the actual chlorination. Such a procedure can be used in a very effective manner if two devices are coupled together as shown in Figure 3. Then e.g. chlorine dioxide solution can be pumped into the inlet 31 on the cylindrical part of the first device 30. The solution can even be added earlier in the pulp stream, e.g. in the conical part after the inlet. The chlorine solution, or chlorine gas dispersed in liquid is added to the second device through connection 34.
Devices according to the invention have proved to be very effect-ive, which is surprising considering the relatively small volume. It is like-ly that the surprisingly good distribution and mixing results depend to a great extent upon the pulp suspension being given a relatively strong rotation with a linear peripheral velocity which is at, or close to, the velocity at which the pulp suspension is fluidized and thereby is leaving the viscoelastic state. This velocity varics with the type of pulp, suspension liquid, and most likely also with the content of gas bubbles in the pulp.
One application of the invention which is very practical is use in connection with oxygen delignification of pulp, whereby one or more devices according to the invention can be used for mixing-in the necessary quantity 16)43147 of oxygen into the pulp. Since, however, oxygen has a very slow solubility in water, the pulp suspension can most suitably be added to a retention tower, reactor, after the distribution and mixing into the pulp. The invention can also be used at superatmospheric pressures such as may be the case in connect-ion with 02-delignification.
Another application of the invention is in connection with the addition of chemical solutions to pulp, when the chemicals are dissolved in great quantities of liquid due to low solubility and added to pulp of high concentration, e.g. 40%, and afterwards distribute and mix during simultaneous dilution of the pulp to e.g. about 10%. Since such high concentration pulp normally is not capable of being transported by pumping, it is possible to provide the device with a vertical inlet through which the pulp, so to speak, can fall. Otherwise the device is independent of a horizontal or vertical shaft.
The invention is furthermore illustrated by the following practical example, in which two devices were coupled together such as shown in Figure 3.
During the trials the pulp was made up of normal birch sulphate pulp and the pulp quantity which was added to the devices was between 50 and 80 tons/24 hours. During the trials chlorine dioxide solution was added to the first device and dispersed chlorine gas in the other device corresponding to a total chlorine consumption of 3.6 weight percent, based on the pulp. The con-centration of the pulp was between 8 and 12% when it arrived from digesting and washing stages. The pulp was pumped to the devices by means of a high density pump and after chlorine treatment the pulp continued to the bottom of a 10 meter high bleach tower with built-in continuous wash devices of the diffuser type. The rotors of the devices were run at about 250 rpm which with the actual apparatus size, with inside largest diameter of 800 mm, correspond-ed to a peripheral velocity of about 10 m/sec in the cylindrical part. The power consumption was 8 KWH per ton of pulp. The temperature of the pulp during the trials was between 40 and 60 C, which is unusually high for 1~43147 chlorination since it normally takes place at room temperature. The higher temperature is, however, a result of the system being closed, and is of course an influence on the reaction speed of the chemicals with the pulp.
This was confirmed through test pieces which showed that approximately all chlorine was consumed during the passage through the devices with a Kappa-number decrease from 18 to 4. Test pieces have shown that the pulp strength characteristics are extremely good and that the viscosity decrease lies within normal values.
It is desirable that such distribution and mixing-in should be as effective as possible, i.e. that the medium or media in the first case are distributed as evenly as possible in the pulp suspension and in the second case the evenness is secured through a mixing of the pulp suspension so that even a relatively small quantity of treatment medium is distributed evenly in and around each individual particle or fiber of the pulp suspension.
The effectiveness of such distribution and mixing is dependent on many factors, such as e.g. the pulp concentration in relation to the quantity of liquid or gas which is to be added, the solubility of the added liquid or gas in the suspension liquid and the reaction speed of the added media with the particles of the pulp suspension. Generally it can be said that the higher the concentration of solids or fibers in the pulp suspension, in other words the less liquid present in the suspension, the more difficult it is to mix-in treatment media so that they are evenly distributed in the suspension. Generally it can also be said that the faster the added media react with the pulp, the more important it is that the media are distributed and mixed-in as quickly and as evenly as possible. such a case occurs e.g.
during treatment of pulp with chlorine in connection with bleaching of the pulp. Chlorine undergoes a specially quick initial reaction with pulp and in order not to dilute the pulp with an unwanted quantity of liquid, chlorine is most often added as gas dispersed in a relatively small quantity of liquid which, however, in turn means that problems can easily arise as to distribution and mixing-in of this relatively small quantity. An object with the invention is therefore to attempt to solve this problem and also the problems which arise when the pulp suspension has a relatively high concentration of fibers, .~
~043~47 preferably above 5%, e.g. from about 8 to 12% or about 10%.
In the pulp industry, the bleaching of pulp with chlorine has hitherto preferably been carried out at 3-4% pulp solids concentration mainly due to mechanical difficulties with mixing-in and distribution, apa~t from gas phase-chlorination in which case the concentration can be in the range 20-50%. Since in other treatment stages of industrial bleach plants, the - pulp concentration is normally kept around 10%, it is desirable also to be able to carry out the chlorine treatment at this same concentration so that one can use uniform equipment in the bleach plant. This has special import-ance for the washing apparatus which is used between the treatment stagesO
Since the treatment with chlorine most often takes place in the beginning of the bleach plant and the pulp therefore must be thickened to about 10%
concentration before the pulp goes on to the next treatment stage, savings and simplifications can be obtained if this first chlorine treatment also can take place at about the same high concentration.
. . .
One aspect of the present invention provides a method for continuously distributing and mixing pulp of relatively high concentration with a treatment liquid or treatment gas, wherein the pulp is continuously led into a device in which the pulp is given a fast circular movement inside a concentric limited surface through which the treatment medium is peripherally and continuously added to contact the pulp in a predominantly even layer distributed over outer moving pulp layer, and thereafter effecting mixing the contact pulp with the distributed medium by changing the circular move-ment of the pulp to a helical movement of decreasing diameter towards an outlet from which the treated pulp is continuously removedO
Another aspect of the invention provides a device for continuous distribution and mixing of pulp of relatively high concentration with at least one treatment liquid or treatment gas, which comprises a closed housing provided with an inlet and outlet for pulp and an inlet for treatment media, and a rotor with blades or wings 1043~7 fastened to one set of arms extending from a rotatably driven shaft, the housing having a cylindrical part inside which the blades are concentrically located close to the cylindrical part, which cylindrical part abuts on one side with a conical part which reduces in diameter to a concentric pulp outlet and on the other side abuts a wall through the centre of which the rotor shaft passes, both the pulp inlet and the treatment media inlet being arranged on the cylindrical part of the housing.
Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings in which:
Figure 1 is a side sectional view of a mixing device;
Figure 2 is a cross-section taken along line A-A of Figure l; and Figure 3 shows a side elevation of two devices coupled together.
The device of Figure 1 consists of a concentric housing 1, in which a rotor 2 can rotate by means of a motor (not shown). The housing 1 includes a cylindrical part 3, a conical front part 4, and a conical back part 5. The rotor 2 has a hub 6, which is fastened to a shaft 7. Transport blades or wings 9 are fastened to the hub by means of a number of arms 8.
The shaft is supported in a bearing housing 10 and sealed against the outside by means of a suitable mechanical sealing or packing box 11. The bearing housing 10 is fastened to the housing 1 by means of supporting bars 12.
With reference to Figure 2 a connection piece 20 is shown through which pulp flows into the device and a connection piece 21 is provided for addition of chemicals. Both connection pieces 20 and 21 are arranged in the cylindrical part 3 of the housing and can be disposed tangentially such as shown for the connection 20. Relative to the direction of the connection 20 the rotor has a rotation direction as shown by arrow 22. After treatment in the device the pulp flows out through opening 13 in the conical front part 4.
The device according to Figures 1 and 2 operates in the following manner. Pulp of a certain concentration, e.g. 10-12%, is added to the device in a continuous flow through the connection 20. The rotor which is rotating with a definite, suitable speed of revolution, causes the incoming pulp to 1~)43~47 rotate intensively. The housing 1 is at all times filled with pulp which later leaves the device through the outlet 13. The rotor wings 9 are made so that the incoming pulp already at the entrance into the inner part of the device is caused to rotate inside the cylindrical part 3 against which the incoming pulp will be thrown due to centrifugal force. A liquid treatment medium or e.g. chlorine gas dispersed in a relatively small quantity of liquid is added through the connection 21. This added liquid quantity which is added peripherally in the cylindrical part 3 will be distributed as a layer ; on top of the pulp fed in just previously and which is rotating as a layer against the cylindrical surface. When the pulp layer with the added chemical layer has rotated around the inner part of the housing and returned back to the inlet 20, a new layer of pulp will add on outside the first one and a new layer of chemicals will add on outside the last mentioned pulp layer. In that way repeated layers will be built up which are forced to move inwardly and outwardly towards the outlet 13 due to the double conical shape of the housing. If it is desired to distribute the chemicals or to add more chemicals, more connections 21 can be arranged successively on the cylindrical part 3.
In practical trials it has been shown that the pulp during movement inside the housing from the cylindrical part 3 out through the conical part 4 towards the outlet 13 undergoes intensive mixing which mainly can be credited the contraction which is taking place in the conical converging zone at the same time as the friction against the housing inner walls slows down the speed of rotation, while the rotation in the central parts of the housing continues since here is being built up an intensive whirling current with inwardly increasing speed of revolution. ~ue to such conditions dis-placements between the pulp layers will take place and the intended mixing - is achieved.
In Figure 3 two, in principle, identical devices are coupled together in a special manner which has proved to be very advantageous during practical trials. The devices have been coupled together with inlet against ~1_ 1~43~47 inlet, which in other words means that inlet 32 and outlet 33 of the first device 30 have opposite functions since the pulp is added to the conical part of the device and leaves this through a tangential outlet which is coupled together with the normal tangential inlet of the other device. It is obvious-ly also possible to couple the devices in series in a more conventional manner in that the pulp is pumped into the tangential inlet of the first de-vice and leaves this one through its conical part which then is coupled to the tangential inlet of the next device in which the pulp leaves through the conical outlet. Depending upon the number of chemical treatments wanted, obviously more devices can be coupled together in the first or last mentioned manner. A treatment which has recently become very common is sequence-chlorination by which is meant that a chlorine-containing medium, e.g.
chlorine dioxide, of certain quantity is added to the pulp before the actual chlorination. Such a procedure can be used in a very effective manner if two devices are coupled together as shown in Figure 3. Then e.g. chlorine dioxide solution can be pumped into the inlet 31 on the cylindrical part of the first device 30. The solution can even be added earlier in the pulp stream, e.g. in the conical part after the inlet. The chlorine solution, or chlorine gas dispersed in liquid is added to the second device through connection 34.
Devices according to the invention have proved to be very effect-ive, which is surprising considering the relatively small volume. It is like-ly that the surprisingly good distribution and mixing results depend to a great extent upon the pulp suspension being given a relatively strong rotation with a linear peripheral velocity which is at, or close to, the velocity at which the pulp suspension is fluidized and thereby is leaving the viscoelastic state. This velocity varics with the type of pulp, suspension liquid, and most likely also with the content of gas bubbles in the pulp.
One application of the invention which is very practical is use in connection with oxygen delignification of pulp, whereby one or more devices according to the invention can be used for mixing-in the necessary quantity 16)43147 of oxygen into the pulp. Since, however, oxygen has a very slow solubility in water, the pulp suspension can most suitably be added to a retention tower, reactor, after the distribution and mixing into the pulp. The invention can also be used at superatmospheric pressures such as may be the case in connect-ion with 02-delignification.
Another application of the invention is in connection with the addition of chemical solutions to pulp, when the chemicals are dissolved in great quantities of liquid due to low solubility and added to pulp of high concentration, e.g. 40%, and afterwards distribute and mix during simultaneous dilution of the pulp to e.g. about 10%. Since such high concentration pulp normally is not capable of being transported by pumping, it is possible to provide the device with a vertical inlet through which the pulp, so to speak, can fall. Otherwise the device is independent of a horizontal or vertical shaft.
The invention is furthermore illustrated by the following practical example, in which two devices were coupled together such as shown in Figure 3.
During the trials the pulp was made up of normal birch sulphate pulp and the pulp quantity which was added to the devices was between 50 and 80 tons/24 hours. During the trials chlorine dioxide solution was added to the first device and dispersed chlorine gas in the other device corresponding to a total chlorine consumption of 3.6 weight percent, based on the pulp. The con-centration of the pulp was between 8 and 12% when it arrived from digesting and washing stages. The pulp was pumped to the devices by means of a high density pump and after chlorine treatment the pulp continued to the bottom of a 10 meter high bleach tower with built-in continuous wash devices of the diffuser type. The rotors of the devices were run at about 250 rpm which with the actual apparatus size, with inside largest diameter of 800 mm, correspond-ed to a peripheral velocity of about 10 m/sec in the cylindrical part. The power consumption was 8 KWH per ton of pulp. The temperature of the pulp during the trials was between 40 and 60 C, which is unusually high for 1~43147 chlorination since it normally takes place at room temperature. The higher temperature is, however, a result of the system being closed, and is of course an influence on the reaction speed of the chemicals with the pulp.
This was confirmed through test pieces which showed that approximately all chlorine was consumed during the passage through the devices with a Kappa-number decrease from 18 to 4. Test pieces have shown that the pulp strength characteristics are extremely good and that the viscosity decrease lies within normal values.
Claims (10)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. Method for continuously distributing and mixing pulp of relatively high concentration with a treatment liquid or treatment gas, wherein the pulp is continuously led into a device in which the pulp is given a fast circular movement inside a concentric limited surface through which the treatment medium is peripherally and continuously added to contact the pulp in a predominantly even layer distributed over outer moving pulp layer, and thereafter effecting mixing the contacted pulp with the distributed medium by changing the circular movement of the pulp to a helical movement of decreasing diameter towards an outlet from which the treated pulp is con-tinuously removed.
2. Method according to claim 1, in which the pulp concentration is above 5%.
3. Method according to claim 1, in which the pulp concentration is from about 8 to 12%.
4. Method according to claim 1, 2 or 3, wherein the treatment medium contains chlorine.
5. Method according to claim 1, wherein the pulp is treated with treatment media comprising chlorine dioxide and chlorine.
6. Method according to claim 5, wherein the chlorine dioxide and chlorine are added to the pulp separately.
7. Device for continuous distribution and mixing of pulp of relative-ly high concentration with at least one treatment liquid or treatment gas, which comprises a closed housing provided with an inlet and outlet for pulp and an inlet for treatment media, and a rotor with blades or wings fastened to one set of arms extending from a rotatably driven shaft, the housing having a cylindrical part inside which the blades are concentrically located close to the cylindrical part, which cylindrical part abuts on one side with a conical part which reduces in diameter to a concentric pulp outlet and on the other side abuts a wall through the centre of which the rotor shaft passes, both the pulp inlet and the treatment media inlet being arranged on the cylindrical part of the housing.
8. Device according to claim 7, wherein the pulp inlet is arranged tangentially on the cylindrical part of the housing and that, seen in the direction of rotation of the blades, at least one treatment medium inlet is arranged closely after the pulp inlet.
9. Device according to claim 7, wherein the pulp inlet of the device is directly, or by means of a short connection piece, connected to the pulp inlet of a substantially identical second device, the normal pulp inlet and outlet of the second device having opposite functions.
10. Device according to claim 9, wherein the coupled devices each have separate treatment media inlets, and wherein the first inlet, as seen in the direction of pulp flow, is intended for chlorine dioxide solution and the second inlet for chlorine solution, chlorine gas or dispersed chlorine gas.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE7502870A SE389351B (en) | 1975-03-14 | 1975-03-14 | METHOD AND DEVICE FOR DISTRIBUTION AND MIXTURE OF GAS AND / OR LIQUID IN MASS CONCENTRATIONS OF HIGH CONCENTRATION. |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1043147A true CA1043147A (en) | 1978-11-28 |
Family
ID=20323961
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA247,730A Expired CA1043147A (en) | 1975-03-14 | 1976-03-11 | Method and device for distribution and mixing-in of gas and/or liquid in pulp suspensions of high concentration |
Country Status (9)
| Country | Link |
|---|---|
| US (1) | US4093506A (en) |
| JP (1) | JPS51114769A (en) |
| BR (1) | BR7601502A (en) |
| CA (1) | CA1043147A (en) |
| DE (1) | DE2608425C3 (en) |
| FI (1) | FI62868C (en) |
| FR (1) | FR2333083A1 (en) |
| NO (1) | NO146334C (en) |
| SE (1) | SE389351B (en) |
Families Citing this family (50)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FI55878C (en) * | 1976-04-28 | 1979-10-10 | Ahlstroem Oy | FOERFARANDE FOER BEHANDLING AV LIGNOCELLULOSAMATERIAL MED KLOR |
| FI62872C (en) * | 1978-06-06 | 1983-03-10 | Ahlstroem Oy | ANORDNING FOER SILNING AV FIBERSUSPENSIONER |
| FR2432574A1 (en) * | 1978-08-01 | 1980-02-29 | Europeen Cellulose | PROCESS FOR BLEACHING PAPER PULP |
| US4298426A (en) * | 1979-06-15 | 1981-11-03 | Weyerhaeuser Company | Method and apparatus for treating pulp with oxygen in a multi-stage bleaching sequence |
| US4288288A (en) * | 1979-06-15 | 1981-09-08 | Weyerhaeuser Company | Apparatus for mixing chemicals into pulp at a refiner inlet |
| US4303470A (en) * | 1979-06-15 | 1981-12-01 | Weyerhaeuser Company | Method and apparatus for mixing gases with a wood pulp slurry |
| US4295926A (en) * | 1979-06-15 | 1981-10-20 | Weyerhaeuser Company | Method and apparatus for treating pulp with oxygen |
| US4295925A (en) * | 1979-06-15 | 1981-10-20 | Weyerhaeuser Company | Treating pulp with oxygen |
| US4295927A (en) * | 1979-06-15 | 1981-10-20 | Weyerhaeuser Company | Method and apparatus for treating pulp with oxygen and storing the treated pulp |
| SE445052C (en) * | 1980-03-13 | 1987-10-29 | Sunds Defibrator | SET AND DEVICE FOR CONTINUOUS MIXING OF GAS AND / OR LIQUID TREATMENTS IN A MASSAGE SUSPENSION |
| US4362536A (en) * | 1981-06-08 | 1982-12-07 | Kamyr, Inc. | Pulp degassing |
| WO1983000816A1 (en) * | 1981-09-04 | 1983-03-17 | Weyerhaeuser Co | Method and apparatus for mixing pulp with oxygen |
| US4515655A (en) * | 1983-08-15 | 1985-05-07 | Westvaco Corporation | Method of bleaching paper pulp by blending chlorine with a flow volume of paper pulp slurry |
| US4662993A (en) * | 1983-08-15 | 1987-05-05 | Westvaco Corporation | Bleach system for dissolving chlorine gas into a bleach filtrate |
| NO164310C (en) * | 1984-03-05 | 1990-09-19 | Kamyr Inc | PROCEDURE FOR THE TREATMENT OF A MECHANICAL MASS WITH HYDROSULPHITE-BLEACH CHEMICALS. |
| FI75882C (en) * | 1985-07-18 | 1988-08-08 | Kamyr Ab | Device for mixing chemicals in fiber suspensions |
| US4842690A (en) * | 1986-05-27 | 1989-06-27 | Kamyr, Inc. | Mixing chlorine gas into paper pulp slurries |
| FI79361B (en) * | 1988-01-05 | 1989-08-31 | Ahlstroem Oy | FOERFARANDE OCH APPARATUR FOER UNDERLAETTANDE AV UTTOEMNING AV FALLROER ELLER LIKNANDE OCH BEHANDLING AV MASSA I SAGDA UTRYMME. |
| US4902381A (en) * | 1988-12-09 | 1990-02-20 | Kamyr, Inc. | Method of bleaching pulp with ozone-chlorine mixtures |
| US5181989A (en) * | 1990-10-26 | 1993-01-26 | Union Camp Patent Holdings, Inc. | Reactor for bleaching high consistency pulp with ozone |
| US5211811A (en) * | 1989-02-15 | 1993-05-18 | Union Camp Patent Holding, Inc. | Process for high consistency oxygen delignification of alkaline treated pulp followed by ozone delignification |
| US5409570A (en) * | 1989-02-15 | 1995-04-25 | Union Camp Patent Holding, Inc. | Process for ozone bleaching of oxygen delignified pulp while conveying the pulp through a reaction zone |
| US5188708A (en) * | 1989-02-15 | 1993-02-23 | Union Camp Patent Holding, Inc. | Process for high consistency oxygen delignification followed by ozone relignification |
| US4976586A (en) * | 1989-07-18 | 1990-12-11 | Kamyr Ab | Pump with separate fluidizing vaned shaft adjacent impeller |
| US5164043A (en) * | 1990-05-17 | 1992-11-17 | Union Camp Patent Holding, Inc. | Environmentally improved process for bleaching lignocellulosic materials with ozone |
| US5164044A (en) * | 1990-05-17 | 1992-11-17 | Union Camp Patent Holding, Inc. | Environmentally improved process for bleaching lignocellulosic materials with ozone |
| US5405497A (en) * | 1990-08-28 | 1995-04-11 | Kamyr, Inc. | Method of chemically reacting a liquid with a gas in a vortex |
| AT394738B (en) * | 1990-09-03 | 1992-06-10 | Andritz Ag Maschf | METHOD AND DEVICE FOR DISCHARGING A MEDIUM FROM A CONTAINER |
| DE69221385T2 (en) * | 1991-05-24 | 1997-12-11 | Union Camp Patent Holding | Two-stage pulp bleaching reactor and method for bleaching with ozone |
| US5258100A (en) * | 1992-02-28 | 1993-11-02 | Kamyr, Inc. | Minimizing gas separation in a mixer outlet |
| US5792316A (en) * | 1992-02-28 | 1998-08-11 | International Paper Company | Bleaching process for kraft pulp employing high consistency chlorinated pulp treated with gaseous chlorine and ozone |
| FI925558A (en) * | 1992-04-22 | 1993-10-23 | Ahlstroem Oy | FOERFARANDE OCH ANORDNING FOER BLEKNING AV MASSA |
| WO1994015017A1 (en) * | 1992-12-18 | 1994-07-07 | Ingersoll-Rand Company | Pulp and bleaching reagent mixer and method |
| US5554259A (en) * | 1993-10-01 | 1996-09-10 | Union Camp Patent Holdings, Inc. | Reduction of salt scale precipitation by control of process stream Ph and salt concentration |
| CA2158522C (en) * | 1994-09-19 | 2001-04-10 | Daniel R. Roll | Mixer for mixing multi-phase fluids |
| EP0865531B1 (en) * | 1995-12-07 | 2002-03-06 | Beloit Technologies, Inc. | Oxygen delignification of medium consistency pulp slurry |
| AT403588B (en) * | 1996-06-26 | 1998-03-25 | Andritz Patentverwaltung | DEVICE FOR DISTRIBUTING SUSPENSIONS, PARTICULARLY CELLULAR SUSPENSIONS, IN A CONTAINER |
| US6193406B1 (en) * | 1996-12-20 | 2001-02-27 | Andritz-Ahlstrom Oy | Method and apparatus for mixing pulp a suspension with a fluid medium with a freely rotatable mixing rotor |
| EP1151788A1 (en) * | 2000-05-05 | 2001-11-07 | Carpos S.A. | Kneading machine with metering device |
| IT1296382B1 (en) | 1997-08-19 | 1999-06-25 | Waltzing Limited Liability Com | PROCESS AND EQUIPMENT FOR THE PRODUCTION OF PIZZAS. |
| US6915734B2 (en) * | 1997-08-19 | 2005-07-12 | Arios, S.A. | Pizza making method and system |
| US6423183B1 (en) | 1997-12-24 | 2002-07-23 | Kimberly-Clark Worldwide, Inc. | Paper products and a method for applying a dye to cellulosic fibers |
| US6379498B1 (en) * | 2000-02-28 | 2002-04-30 | Kimberly-Clark Worldwide, Inc. | Method for adding an adsorbable chemical additive to pulp during the pulp processing and products made by said method |
| US6749721B2 (en) | 2000-12-22 | 2004-06-15 | Kimberly-Clark Worldwide, Inc. | Process for incorporating poorly substantive paper modifying agents into a paper sheet via wet end addition |
| US7749356B2 (en) | 2001-03-07 | 2010-07-06 | Kimberly-Clark Worldwide, Inc. | Method for using water insoluble chemical additives with pulp and products made by said method |
| US6582560B2 (en) | 2001-03-07 | 2003-06-24 | Kimberly-Clark Worldwide, Inc. | Method for using water insoluble chemical additives with pulp and products made by said method |
| US6863429B2 (en) * | 2002-01-07 | 2005-03-08 | Artos, S.A. | Dough mixer with metering device |
| US6916402B2 (en) | 2002-12-23 | 2005-07-12 | Kimberly-Clark Worldwide, Inc. | Process for bonding chemical additives on to substrates containing cellulosic materials and products thereof |
| US7670459B2 (en) * | 2004-12-29 | 2010-03-02 | Kimberly-Clark Worldwide, Inc. | Soft and durable tissue products containing a softening agent |
| WO2009087193A1 (en) * | 2008-01-11 | 2009-07-16 | Sulzer Pumpen Ag | Method and apparatus for mixing of fluids |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB764425A (en) * | 1954-07-19 | 1956-12-28 | Giulio Consiglio | Process of and apparatus for continuously chlorinating semi-chemical cellulose |
| US3074786A (en) * | 1959-12-17 | 1963-01-22 | Shell Oil Co | Fluid mixer with rotating baffles and method of operating same |
| US3293117A (en) * | 1963-03-27 | 1966-12-20 | Improved Machinery Inc | High density pulp mixing |
| US3301027A (en) * | 1965-05-10 | 1967-01-31 | Improved Machinery Inc | Pulp treatment apparatus |
| SE311109B (en) * | 1967-11-30 | 1969-05-27 | Billeruds Ab | |
| US3630828A (en) * | 1968-05-13 | 1971-12-28 | Pulp Paper Res Inst | Bleaching of a low-density, substantially uncompacted, porous fluffed cellulosic pulp |
| CA902859A (en) * | 1969-11-26 | 1972-06-20 | Pulp And Paper Research Institute Of Canada | Chemical reaction between a solid and a gas |
| US3833461A (en) * | 1971-05-17 | 1974-09-03 | Bauer Bros Co | Cyclonic digester system and process |
| US3966542A (en) * | 1974-09-20 | 1976-06-29 | General Signal Corporation | Multi-stage bleaching of pulp using successively lower power levels |
-
1975
- 1975-03-14 SE SE7502870A patent/SE389351B/en not_active IP Right Cessation
-
1976
- 1976-02-23 FI FI760444A patent/FI62868C/en not_active IP Right Cessation
- 1976-03-01 DE DE2608425A patent/DE2608425C3/en not_active Expired
- 1976-03-05 NO NO760772A patent/NO146334C/en unknown
- 1976-03-10 US US05/665,576 patent/US4093506A/en not_active Expired - Lifetime
- 1976-03-10 JP JP51025196A patent/JPS51114769A/en active Granted
- 1976-03-11 CA CA247,730A patent/CA1043147A/en not_active Expired
- 1976-03-11 FR FR7607012A patent/FR2333083A1/en active Granted
- 1976-03-12 BR BR7601502A patent/BR7601502A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| DE2608425C3 (en) | 1978-09-14 |
| BR7601502A (en) | 1976-09-14 |
| NO146334B (en) | 1982-06-01 |
| JPS51114769A (en) | 1976-10-08 |
| DE2608425B2 (en) | 1978-01-05 |
| FR2333083A1 (en) | 1977-06-24 |
| DE2608425A1 (en) | 1976-09-16 |
| FI62868B (en) | 1982-11-30 |
| NO146334C (en) | 1982-09-08 |
| JPS565875B2 (en) | 1981-02-07 |
| FR2333083B1 (en) | 1979-04-06 |
| US4093506A (en) | 1978-06-06 |
| FI62868C (en) | 1983-03-10 |
| FI760444A (en) | 1976-09-15 |
| NO760772L (en) | 1976-09-15 |
| SE7502870L (en) | 1976-09-15 |
| SE389351B (en) | 1976-11-01 |
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