EP0167060A1 - A process for dispersing one fluid in another - Google Patents
A process for dispersing one fluid in another Download PDFInfo
- Publication number
- EP0167060A1 EP0167060A1 EP85107565A EP85107565A EP0167060A1 EP 0167060 A1 EP0167060 A1 EP 0167060A1 EP 85107565 A EP85107565 A EP 85107565A EP 85107565 A EP85107565 A EP 85107565A EP 0167060 A1 EP0167060 A1 EP 0167060A1
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- European Patent Office
- Prior art keywords
- fluid
- streams
- opening
- section
- pulp
- Prior art date
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Classifications
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- 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
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- 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
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- 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
- B01F25/313—Injector mixers in conduits or tubes through which the main component flows wherein additional components are introduced in the centre of the conduit
-
- 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
- B01F25/313—Injector mixers in conduits or tubes through which the main component flows wherein additional components are introduced in the centre of the conduit
- B01F25/3132—Injector mixers in conduits or tubes through which the main component flows wherein additional components are introduced in the centre of the conduit by using two or more injector devices
-
- 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
- B01F25/313—Injector mixers in conduits or tubes through which the main component flows wherein additional components are introduced in the centre of the conduit
- B01F25/3132—Injector mixers in conduits or tubes through which the main component flows wherein additional components are introduced in the centre of the conduit by using two or more injector devices
- B01F25/31323—Injector mixers in conduits or tubes through which the main component flows wherein additional components are introduced in the centre of the conduit by using two or more injector devices used successively
-
- 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
- B01F25/313—Injector mixers in conduits or tubes through which the main component flows wherein additional components are introduced in the centre of the conduit
- B01F25/3133—Injector mixers in conduits or tubes through which the main component flows wherein additional components are introduced in the centre of the conduit characterised by the specific design of the injector
- B01F25/31331—Perforated, multi-opening, with a plurality of holes
Definitions
- This invention relates to a process for dispersing a fluid, which may be a gas or liquid, into a high viscosity liquid.
- Such a system is the bleaching of medium consistency pulp with gaseous oxygen or with aqueous solutions of chlorine dioxide, hydrogen peroxide, or sodium hypochlorite.
- the bleaching is intended to whiten and brighten the pulp without damaging the strength characteristics of the paper to be made from the pulp.
- the main light absorbing substances in wood pulp are the lignin and resin components. Therefore, to make the pulp whiter, these substances must be removed.
- Oxidation, reduction, or hydrolysis make the lignin and resin components soluble so that they can be washed away by aqueous solutions.
- the initial solubilization of the bulk of the lignin is carried out with non-oxidizing substances such as alkalies, sulfides, or sulfites; however, continuation of the dissolution by this means is found to seriously degrade the carbohydrate fraction of the pulp, affecting both strength and yield. Since lignin is readily oxidized by many substances, the remainder, then, is removed by oxidation and dissolution of the oxidized products in water and aqueous alkali. Chlorine, chlorine dioxide, hypochlorite, hydrogen peroxide, ozone, and oxygen can be used separately or in various combinations as oxidizing agents.
- Pulp bleaching plants generally treat the pulp in a continuous flow mode with a series of oxidizing agents.
- An alkaline treatment step is often provided between some of the oxidizing treatment steps with a water wash after each step.
- a typical sequence would be to start with an aqueous chlorine treatment, then a water wash, an alkaline treatment, water wash, aqueous chlorine dioxide treatment, and a final water wash.
- the apparatus in which these steps are conventionally carried out are, in order of use, a chlorination tower, a water washer, a steam mixer, a thick stock pump, an upflow or downflow extraction tower, a water washer, a chlorine dioxide mixer, a chlorine dioxide tower, and a water washer.
- the pulp entering the alkaline extraction tower is of medium consistency, containing about ten to about fifteen percent by weight of dry pulp admixed with an alkaline aqueous solution. Its flow characteristics, or viscosity, are comparable to that of ground meat or damp papier-mache. If the oxygen gas is not well dispersed within the pulp mass, it will not be able to reach most of the pulp and the desired reaction will not be able to take place in the portion of the pulp mass unexposed to the oxygen.
- the first commercial plants using oxygen with medium consistency pulp achieved adequate dispersion of the oxygen gas in the pulp by employing dynamic mechanical mixers.
- Such mixers are complicated pieces of equipment with high capital, maintenance, and operational costs.
- An object of the invention is to provide a process which will disperse one fluid uniformly throughout another fluid where one of the fluids characteristically has a relatively high viscosity thus achieving an otherwise difficult to attain level of dispersion without mechanical mixing devices.
- While the invention will be described in terms of an important application, i.e., pulp bleaching, it has application in many other industrial processes such as dispersing dyes in high viscosity polymers; dispersing additives in high viscosity food materials; and blending epoxy components, and other processes where dispersion of one material in another is considered to be a critical factor.
- Liquid/liquid and gas/liquid mixtures are contemplated, the fluid having the relatively higher viscosity, of course, being a liquid or semi-liquid.
- the liquid to be dispersed can also have a relatively high viscosity provided that it is capable of being passed through the second confined zones and the ports.
- the process provides a series of steps whereby a plurality of small streams is introduced across the flow of a high viscosity fluid, the flow pattern being achieved with minimal pressure drop.
- the number of streams is in the range of about 25 streams per square foot of cross-section of the confined zone to about 1000 streams per square foot of the cross-section.
- the cross-section used here is a cross-section perpendicular to the hypothetical central axis referred to above.
- the cross-section is selected at any point in the confined zone at which all of the streams have been formed. This is usually between the midpoint of the axis and the downstream end of the zone, preferably closer to the midpoint.
- the preferred number of streams is in the range of about 50 to about 600 streams per square foot.
- the streams are about equidistant from one another, the distance between streams being about 0.375 to about 2.5 inches and preferably about 0.5 to about 1.7 inches.
- the direction of flow of these small streams of liquid or gas bubbles is defined by the flow of the relatively higher viscosity fluid.
- the dispersion can be enhanced with the use of a mixing device such as a static mixer located downstream of the apparatus used to carry out subject process.
- a typical static mixer has a multiplicity of baffles located in a pipe.
- the baffles sequentially subdivide and mix material flowing through the pipe.
- the utilization of subject process upstream of the static mixer permits a reduction in the number of baffles (or mixing elements) in the static mixer.
- the apparatus which can be used to carry out the process of this invention is low in capital cost, low in maintenance expense, and requires minimum modifications to existing plant equipment.
- the process itself is one in which medium consistency pulp can be profitably treated (i) with oxygen prior to the first alkaline bleach stage or (ii) with other bleach chemicals such as chlorine dioxide, hypochlorite, or hydrogen peroxide in aqueous solutions, both resulting in a reduction in the overall cost of bleach chemicals.
- a preferred apparatus utilizes a series of relatively small diameter perforated or porous pipes within a relatively larger diameter pipe.
- the larger diameter pipe is referred to as the confined zone.
- the pipes are made of conventional materials such as stainless steel.
- the large pipe is placed between the thick stock pump and the first alkaline extraction tower.
- the main stream of pulp or pulp mass flowing through the large pipe comprises a mixture of about 10 to about 15 parts by weight pulp solids with, the balance, a solution of water and alkali, usually dilute. This is considered a medium consistency pulp.
- a plurality of uniform continuous or discontinuous streams of oxygen flow in a downstream direction from the perforations or pores of the small diameter pipes.
- the flow rate of the pulp mass stream is about 150 to about 1000 metric tons of pulp solids per day.
- the flow rate of the oxygen is about 800 standard cubic feet per hour (scfh) to about 5500 scfh.
- the small pipes are considered to be arranged in sets and there are several of these sets in the large pipe. Spacing between the small pipes in a set and between the sets themselves is balanced so that bridging is avoided without sacrificing uniformity of dispersion.
- the diameter and placement of the small pipes are also a factor affecting bridging. Bridging is caused by, for example, the accumulation of a highly viscous fibrous material in the path of flow, eventually blocking it. It is of especial concern with medium consistency pulp because the pulp begins to lose water as the bridge forms causing the bridging pulp to become increasingly more rigid.
- the rate at which the bridge forms and the amount of bridge formation are a function of the nature of the fibrous mass such as fiber length, the kind of fiber, prior treatment of the fiber, and the lubricating properties of the first fluid.
- the small pipes in each set are about equally spaced from one another and about 1 to about 10 inches apart, preferably about 3 to about 5 inches apart.
- the sets of pipes are spaced apart from one another by about 1 to about 12 inches, preferably about 3 to about 6 inches. It is also preferred that the pipes in each set are in a staggered relationship to the pipes in the other sets. In this case, if one were to take an upstream/ downstream cross-section through one of the small pipes in a three set system, there would only be one pipe in the cross-section.
- pipe 21 encloses the confined zone. It is supported by flanges 22 and 23. Various braces and welds(not shown) also provide support for the structure.
- Annular chamber 24 is formed by ring 25 and closure rings 26. It has an inlet pipe 27 and an outlet valve 28. Small pipes 1, 4, 7. 10, 13, and 16 represent the first set of small pipes; small pipes 2, 5, 8, 11, and 14 represent the second set;and small pipes 3, 6, 9. 12, and 15, the third set.
- Hypothetical axis 29 of pipe 21 runs from the upstream end to the downstream end. Small pipes 1, 2, and 3 as well as the other small pipes are perpendicular to hypothetical axis 29.
- the small pipes may also be inclined insofar as hypothetical axis 29 is concerned, the angle of inclination lying in the range of about 20° to about 90°. It is preferred that the angle be the same for all small pipes.
- each set lies in its own plane and each plane bears a spaced relationship to each other plane. While a plane is ususally described as two dimensional, i.e., without height or depth, in this context it is considered to have a height or depth equal to the diameter of the zones or pipes of the set which lie in the plane.
- the plane bears the same angle of inclination as the pipes in the set, which lies in that plane.
- Both ends of each small pipe are open. These ends are referred to as inlet ports 30.
- Figure 3 is an enlargement of one of the small pipes 2 through 15 showing outlet ports 31 in a staggered array.
- the small pipe has a hypothetical axis 32 which, of course, would be perpendicular to hypothetical axis 29 if shown in Figure 2.
- Figure 4 is an enlargement of a section of the small pipe shown in Figure 3.
- Figure 5 is a cross-section of the small pipes shown in Figures 3 and 4.
- Axes 33 of outlet ports 31 are at a ninety degree angle to each other, and perpendicular to hypothetical axis 32.
- each outlet port is at an angle of about 0° to about 90°, and preferably about 45°, from a hypothetical line 34 running downstream from the point at which the central axis of the outlet port meets the central axis of the small pipe, said hypothetical line being perpendicular to the central axis of the small pipe, parallel to the central axis of the confined zone, and lying in the same plane as the central axis of the outlet port.
- the apparatus is located in a softwood, kraft pulp bleach plant using a conventional bleaching process.
- the normal flow rate through the apparatus is 350 metric tons per day of pulp solids (or pulp mass on an air dried basis).
- Pulp mass from the washer following the chlorine stage is made alkaline and is heated prior to being pumped into the bottom of a standard upflow alkaline extraction reaction tower.
- the initial pulp mass is a mixture of 11 percent pulp solids and 89 percent water.
- the apparatus is inserted into a 24 inch diameter pipe line, which carries the pulp mass into the bottom of the upflow tower.
- Pipe 21 is 23.25 inches in inner diameter and is 18 inches long. There are sixteen small pipes, placed as shown in the drawing, equidistant from adjacent pipes.
- the small pipes are 0.30 inch in inner diameter and 0.54 inch in outer diameter. They are Schedule 80 pipes made of AISI 304 stainless steel. Small pipes 1 and 16 have one row of outlet ports 31 and small pipes 2 through 15 have two rows of outlet ports 31. Each row of outlet ports 31 is centered on its small pipe, e.g. where the small pipe is 10.5 inches long, the row is only about 6.5 inches long and two inches at either end of the pipe have no outlet ports.
- the lengths of each, i.e., pipe and row are as follows: Outlet ports 31 have inner diameters of 0.025 inch and are three inches apart from adjacent outlet ports 31 in the same row.
- outlet ports 31 in each of small pipes 2 to 15 were in the same row, they would be 1.5 inches apart.
- the axes of outlet ports 31 are at the angles shown in Figure 5, the axes of outlet ports 31 in small pipes 1 and 16 being directed to the interior of pipe 21.
- the number of streams per square foot of cross-section is 64.
- Oxygen at a pressure of about 120 psig is introduced through inlet pipe 27 (one inch internal diameter, Schedule 40) into annular chamber 24. It then passes into the small pipes through inlet ports 30 and out through outlet ports 31 into pipe 21 (wall 0.375 inch thick). The amount of oxygen introduced is 4 kilograms per metric ton of pulp solids.
Abstract
- (a) providing a confined zone (21) having an opening at its upstream end, an opening at its downstream end, and a hypothetical central axis (29) running from its upstream end to its downstream end;
- (b) introducing the second fluid into the confined zone (21) at the opening in its upstream end in such a manner that the second fluid passes from the opening in the upstream end through the opening in the downstream end;
- (c) dividing the first fluid into a plurality of streams and introducing the streams into the second fluid co-currently therewith whereby:
- (i) the number of streams is in the range of about 25 streams per square foot of a cross-section of the confined zone to about 1000 streams per square foot of the cross-section;
- (ii) the cross-section is perpendicular to the axis (29); and
- (iii) the streams are about equidistant from one another, the distance between the streams being about 0.375 to about 2.5 inches.
Description
- This invention relates to a process for dispersing a fluid, which may be a gas or liquid, into a high viscosity liquid.
- In certain types of systems involving the reaction and/or blending of a material or fluid of relatively high viscosity with a second fluid, it is desirable to uniformly disperse the second fluid throughout the mass of high viscosity material. Such a system is the bleaching of medium consistency pulp with gaseous oxygen or with aqueous solutions of chlorine dioxide, hydrogen peroxide, or sodium hypochlorite. The bleaching is intended to whiten and brighten the pulp without damaging the strength characteristics of the paper to be made from the pulp. The main light absorbing substances in wood pulp are the lignin and resin components. Therefore, to make the pulp whiter, these substances must be removed. Oxidation, reduction, or hydrolysis make the lignin and resin components soluble so that they can be washed away by aqueous solutions. The initial solubilization of the bulk of the lignin is carried out with non-oxidizing substances such as alkalies, sulfides, or sulfites; however, continuation of the dissolution by this means is found to seriously degrade the carbohydrate fraction of the pulp, affecting both strength and yield. Since lignin is readily oxidized by many substances, the remainder, then, is removed by oxidation and dissolution of the oxidized products in water and aqueous alkali. Chlorine, chlorine dioxide, hypochlorite, hydrogen peroxide, ozone, and oxygen can be used separately or in various combinations as oxidizing agents.
- Pulp bleaching plants generally treat the pulp in a continuous flow mode with a series of oxidizing agents. An alkaline treatment step is often provided between some of the oxidizing treatment steps with a water wash after each step. A typical sequence would be to start with an aqueous chlorine treatment, then a water wash, an alkaline treatment, water wash, aqueous chlorine dioxide treatment, and a final water wash. The apparatus in which these steps are conventionally carried out are, in order of use, a chlorination tower, a water washer, a steam mixer, a thick stock pump, an upflow or downflow extraction tower, a water washer, a chlorine dioxide mixer, a chlorine dioxide tower, and a water washer.
- It has been known for some time that the addition of about five kilograms of oxygen gas per metric ton of dry pulp to the process between the aqueous chlorine treatment step and the alkaline treatment step permits equivalent levels of bleaching to be obtained at reduced chlorine dioxide(or other oxidant) requirements. The relatively high viscosity of the pulp makes it difficult to disperse the oxygen gas uniformly throughout the pulp. The reason for the difficulty lies in the fact that it is necessary to create turbulence in the viscous material in order to obtain a good dispersion, and early mixing techniques were just not up to this task.
- Typically, the pulp entering the alkaline extraction tower is of medium consistency, containing about ten to about fifteen percent by weight of dry pulp admixed with an alkaline aqueous solution. Its flow characteristics, or viscosity, are comparable to that of ground meat or damp papier-mache. If the oxygen gas is not well dispersed within the pulp mass, it will not be able to reach most of the pulp and the desired reaction will not be able to take place in the portion of the pulp mass unexposed to the oxygen.
- The first commercial plants using oxygen with medium consistency pulp achieved adequate dispersion of the oxygen gas in the pulp by employing dynamic mechanical mixers. Such mixers, however, are complicated pieces of equipment with high capital, maintenance, and operational costs.
- An object of the invention, therefore, is to provide a process which will disperse one fluid uniformly throughout another fluid where one of the fluids characteristically has a relatively high viscosity thus achieving an otherwise difficult to attain level of dispersion without mechanical mixing devices.
- Other objects and advantages will become apparent hereinafter.
- According to the present invention, an improvement has been discovered in a process for dispersing a first fluid in a second fluid having a relatively higher viscosity comprising the following steps:
- (a) providing a confined zone having an opening at its upstream end, an opening at its downstream end, and a hypothetical central axis running from its upstream end to its downstream end;
- (b) introducing the second fluid into the confined zone at the opening in its upstream end in such a manner that the second fluid passes from the opening in the upstream end through the opening in the downstream end:
- (c) dividing the first fluid into a plurality of streams and introducing the streams into the second fluid co-currently therewith whereby:
- (i) the number of streams is in the range of about 25 streams per square foot of a cross-section of the confined zone to about 1000 streams per square foot of the cross-section;
- (ii) the cross-section is perpendicular to the axis; and
- (iii) the streams are about equidistant from one another, the distance between the streams being about 0.375 to about 2.5 inches.
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- Figure 1 is a schematic diagram of a view of a cross-section taken from the upstream or downstream end of one embodiment of the invention.
- Figure 2 is a side view cross-section of the same embodiment seen in Figure 1.
- Figure 3 is a schematic diagram of one of the small pipes shown in Figure 1 taken from the downstream end and showing two rows of outlet ports. The small pipe has been enlarged over its counterpart in'Figure 1.
- Figure 4 is a schematic diagram of an enlarged section of Figure 3 showing some of the outlet ports.
- Figure 5 is a schematic diagram of a plan view cross-section of Figure 4 showing detail of the outlet ports.
- While the invention will be described in terms of an important application, i.e., pulp bleaching, it has application in many other industrial processes such as dispersing dyes in high viscosity polymers; dispersing additives in high viscosity food materials; and blending epoxy components, and other processes where dispersion of one material in another is considered to be a critical factor. Liquid/liquid and gas/liquid mixtures are contemplated, the fluid having the relatively higher viscosity, of course, being a liquid or semi-liquid. The liquid to be dispersed can also have a relatively high viscosity provided that it is capable of being passed through the second confined zones and the ports.
- The process provides a series of steps whereby a plurality of small streams is introduced across the flow of a high viscosity fluid, the flow pattern being achieved with minimal pressure drop. The number of streams is in the range of about 25 streams per square foot of cross-section of the confined zone to about 1000 streams per square foot of the cross-section. The cross-section used here is a cross-section perpendicular to the hypothetical central axis referred to above. The cross-section is selected at any point in the confined zone at which all of the streams have been formed. This is usually between the midpoint of the axis and the downstream end of the zone, preferably closer to the midpoint. The preferred number of streams is in the range of about 50 to about 600 streams per square foot. The streams are about equidistant from one another, the distance between streams being about 0.375 to about 2.5 inches and preferably about 0.5 to about 1.7 inches. The direction of flow of these small streams of liquid or gas bubbles is defined by the flow of the relatively higher viscosity fluid. The dispersion can be enhanced with the use of a mixing device such as a static mixer located downstream of the apparatus used to carry out subject process.
- A typical static mixer has a multiplicity of baffles located in a pipe. The baffles sequentially subdivide and mix material flowing through the pipe. The utilization of subject process upstream of the static mixer permits a reduction in the number of baffles (or mixing elements) in the static mixer.
- It is advantageous that the apparatus, which can be used to carry out the process of this invention is low in capital cost, low in maintenance expense, and requires minimum modifications to existing plant equipment. In addition to these advantages, the process itself is one in which medium consistency pulp can be profitably treated (i) with oxygen prior to the first alkaline bleach stage or (ii) with other bleach chemicals such as chlorine dioxide, hypochlorite, or hydrogen peroxide in aqueous solutions, both resulting in a reduction in the overall cost of bleach chemicals.
- A preferred apparatus utilizes a series of relatively small diameter perforated or porous pipes within a relatively larger diameter pipe. The larger diameter pipe is referred to as the confined zone. The pipes are made of conventional materials such as stainless steel. In a typical pulp bleaching system employing oxygen in an oxidative extraction, the large pipe is placed between the thick stock pump and the first alkaline extraction tower. The main stream of pulp or pulp mass flowing through the large pipe comprises a mixture of about 10 to about 15 parts by weight pulp solids with, the balance, a solution of water and alkali, usually dilute. This is considered a medium consistency pulp. A plurality of uniform continuous or discontinuous streams of oxygen flow in a downstream direction from the perforations or pores of the small diameter pipes. The flow rate of the pulp mass stream is about 150 to about 1000 metric tons of pulp solids per day. The flow rate of the oxygen is about 800 standard cubic feet per hour (scfh) to about 5500 scfh.
- The small pipes are considered to be arranged in sets and there are several of these sets in the large pipe. Spacing between the small pipes in a set and between the sets themselves is balanced so that bridging is avoided without sacrificing uniformity of dispersion. The diameter and placement of the small pipes are also a factor affecting bridging. Bridging is caused by, for example, the accumulation of a highly viscous fibrous material in the path of flow, eventually blocking it. It is of especial concern with medium consistency pulp because the pulp begins to lose water as the bridge forms causing the bridging pulp to become increasingly more rigid. The rate at which the bridge forms and the amount of bridge formation are a function of the nature of the fibrous mass such as fiber length, the kind of fiber, prior treatment of the fiber, and the lubricating properties of the first fluid.
- The small pipes in each set are about equally spaced from one another and about 1 to about 10 inches apart, preferably about 3 to about 5 inches apart. The sets of pipes are spaced apart from one another by about 1 to about 12 inches, preferably about 3 to about 6 inches. It is also preferred that the pipes in each set are in a staggered relationship to the pipes in the other sets. In this case, if one were to take an upstream/ downstream cross-section through one of the small pipes in a three set system, there would only be one pipe in the cross-section.
- There are about 2 to about 6 sets provided in the confined zone and preferably about 3 to about 5 sets and there are about 3 to about 8 small pipes per set, about 2 to about 6 small pipes per set being preferred.
- In Figures 1 and 2,
pipe 21 encloses the confined zone. It is supported byflanges Annular chamber 24 is formed byring 25 and closure rings 26. It has aninlet pipe 27 and anoutlet valve 28.Small pipes 1, 4, 7. 10, 13, and 16 represent the first set of small pipes;small pipes 2, 5, 8, 11, and 14 represent the second set;andsmall pipes Hypothetical axis 29 ofpipe 21 runs from the upstream end to the downstream end. Small pipes 1, 2, and 3 as well as the other small pipes are perpendicular tohypothetical axis 29. The small pipes may also be inclined insofar ashypothetical axis 29 is concerned, the angle of inclination lying in the range of about 20° to about 90°. It is preferred that the angle be the same for all small pipes. Further, each set lies in its own plane and each plane bears a spaced relationship to each other plane. While a plane is ususally described as two dimensional, i.e., without height or depth, in this context it is considered to have a height or depth equal to the diameter of the zones or pipes of the set which lie in the plane. The plane bears the same angle of inclination as the pipes in the set, which lies in that plane. Both ends of each small pipe are open. These ends are referred to asinlet ports 30. - Figure 3 is an enlargement of one of the small pipes 2 through 15 showing
outlet ports 31 in a staggered array. The small pipe has ahypothetical axis 32 which, of course, would be perpendicular tohypothetical axis 29 if shown in Figure 2. - Figure 4 is an enlargement of a section of the small pipe shown in Figure 3.
- Figure 5 is a cross-section of the small pipes shown in Figures 3 and 4.
Axes 33 ofoutlet ports 31 are at a ninety degree angle to each other, and perpendicular tohypothetical axis 32. - The angle is more particularly defined as follows: the central axis of each outlet port is at an angle of about 0° to about 90°, and preferably about 45°, from a hypothetical line 34 running downstream from the point at which the central axis of the outlet port meets the central axis of the small pipe, said hypothetical line being perpendicular to the central axis of the small pipe, parallel to the central axis of the confined zone, and lying in the same plane as the central axis of the outlet port.
- The following example illustrates the invention:
- Subject process is carried out in the apparatus described above. The apparatus is located in a softwood, kraft pulp bleach plant using a conventional bleaching process. The normal flow rate through the apparatus is 350 metric tons per day of pulp solids (or pulp mass on an air dried basis). Pulp mass from the washer following the chlorine stage is made alkaline and is heated prior to being pumped into the bottom of a standard upflow alkaline extraction reaction tower. The initial pulp mass is a mixture of 11 percent pulp solids and 89 percent water. The apparatus is inserted into a 24 inch diameter pipe line, which carries the pulp mass into the bottom of the upflow tower.
Pipe 21 is 23.25 inches in inner diameter and is 18 inches long. There are sixteen small pipes, placed as shown in the drawing, equidistant from adjacent pipes. There are three sets of small pipes, the sets being spaced four inches apart. The small pipes are 0.30 inch in inner diameter and 0.54 inch in outer diameter. They are Schedule 80 pipes made of AISI 304 stainless steel.Small pipes 1 and 16 have one row ofoutlet ports 31 and small pipes 2 through 15 have two rows ofoutlet ports 31. Each row ofoutlet ports 31 is centered on its small pipe, e.g. where the small pipe is 10.5 inches long, the row is only about 6.5 inches long and two inches at either end of the pipe have no outlet ports. The lengths of each, i.e., pipe and row, are as follows:Outlet ports 31 have inner diameters of 0.025 inch and are three inches apart fromadjacent outlet ports 31 in the same row. Thus, if all of theoutlet ports 31 in each of small pipes 2 to 15 were in the same row, they would be 1.5 inches apart. The axes ofoutlet ports 31 are at the angles shown in Figure 5, the axes ofoutlet ports 31 insmall pipes 1 and 16 being directed to the interior ofpipe 21. The number of streams per square foot of cross-section is 64. - Oxygen at a pressure of about 120 psig is introduced through inlet pipe 27 (one inch internal diameter, Schedule 40) into
annular chamber 24. It then passes into the small pipes throughinlet ports 30 and out throughoutlet ports 31 into pipe 21 (wall 0.375 inch thick). The amount of oxygen introduced is 4 kilograms per metric ton of pulp solids. - It is found that the quantity of bleach chemicals required to achieve the plant's target brightness of 90 Elephro is substantially reduced, e.g., a reduction of 18 percent in chlorine dioxide and of 8 percent in chlorine is found.
Claims (7)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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US62245284A | 1984-06-20 | 1984-06-20 | |
US622452 | 1990-12-05 |
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Publication Number | Publication Date |
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EP0167060A1 true EP0167060A1 (en) | 1986-01-08 |
EP0167060B1 EP0167060B1 (en) | 1990-01-31 |
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EP85107565A Expired - Lifetime EP0167060B1 (en) | 1984-06-20 | 1985-06-19 | A process for dispersing one fluid in another |
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Country | Link |
---|---|
EP (1) | EP0167060B1 (en) |
JP (1) | JPS6146229A (en) |
KR (1) | KR860000446A (en) |
BR (1) | BR8502924A (en) |
CA (1) | CA1262722A (en) |
DE (1) | DE3575680D1 (en) |
DK (1) | DK278285A (en) |
ES (1) | ES8604031A1 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0504550A1 (en) * | 1991-03-20 | 1992-09-23 | H.KRANTZ - TKT Gesellschaft mit beschränkter Haftung | Mixing chamber |
EP0526392A1 (en) * | 1991-07-30 | 1993-02-03 | Sulzer Chemtech AG | Mixing-in device for small amounts of fluid |
WO1995026226A1 (en) * | 1994-03-25 | 1995-10-05 | Siemens Aktiengesellschaft | Combined feed and mixing installation |
US10722860B2 (en) | 2013-01-15 | 2020-07-28 | The University Of Nottingham | Mixing reactor and related process |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2286694A1 (en) * | 1974-10-04 | 1976-04-30 | Basf Ag | Blending equipment for mixing high and low viscosity liquids - e.g. distributing blowing agent into polymer melts |
US3985005A (en) * | 1974-03-14 | 1976-10-12 | Sunds Aktiebolag | Apparatus for processing liquid-containing substance mixtures, particularly cellulose pulp |
GB2015360A (en) * | 1978-03-06 | 1979-09-12 | Komax Systems Inc | A mixing apparatus incorporating a fluid injector |
GB2095123A (en) * | 1981-03-24 | 1982-09-29 | Bergwerksverband Gmbh | Apparatus for introducing a gas into a liquid or a liquid-solids mixture |
EP0106460A1 (en) * | 1982-09-30 | 1984-04-25 | The Black Clawson Company | Improved method and apparatus for oxygen delignification |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1536448A (en) * | 1976-06-01 | 1978-12-20 | Emi Ltd | Radiography |
JPS5939176B2 (en) * | 1976-11-29 | 1984-09-21 | バブコツク日立株式会社 | fluid injection mixing device |
-
1985
- 1985-06-07 CA CA000483430A patent/CA1262722A/en not_active Expired
- 1985-06-18 BR BR8502924A patent/BR8502924A/en unknown
- 1985-06-19 ES ES544361A patent/ES8604031A1/en not_active Expired
- 1985-06-19 DE DE8585107565T patent/DE3575680D1/en not_active Expired - Lifetime
- 1985-06-19 KR KR1019850004345A patent/KR860000446A/en not_active Application Discontinuation
- 1985-06-19 JP JP60132080A patent/JPS6146229A/en active Pending
- 1985-06-19 EP EP85107565A patent/EP0167060B1/en not_active Expired - Lifetime
- 1985-06-19 DK DK278285A patent/DK278285A/en not_active Application Discontinuation
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3985005A (en) * | 1974-03-14 | 1976-10-12 | Sunds Aktiebolag | Apparatus for processing liquid-containing substance mixtures, particularly cellulose pulp |
FR2286694A1 (en) * | 1974-10-04 | 1976-04-30 | Basf Ag | Blending equipment for mixing high and low viscosity liquids - e.g. distributing blowing agent into polymer melts |
GB2015360A (en) * | 1978-03-06 | 1979-09-12 | Komax Systems Inc | A mixing apparatus incorporating a fluid injector |
GB2095123A (en) * | 1981-03-24 | 1982-09-29 | Bergwerksverband Gmbh | Apparatus for introducing a gas into a liquid or a liquid-solids mixture |
EP0106460A1 (en) * | 1982-09-30 | 1984-04-25 | The Black Clawson Company | Improved method and apparatus for oxygen delignification |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0504550A1 (en) * | 1991-03-20 | 1992-09-23 | H.KRANTZ - TKT Gesellschaft mit beschränkter Haftung | Mixing chamber |
EP0526392A1 (en) * | 1991-07-30 | 1993-02-03 | Sulzer Chemtech AG | Mixing-in device for small amounts of fluid |
US5380088A (en) * | 1991-07-30 | 1995-01-10 | Sulzer Brothers Limited | Mixing device for small fluid quantities |
WO1995026226A1 (en) * | 1994-03-25 | 1995-10-05 | Siemens Aktiengesellschaft | Combined feed and mixing installation |
US5749651A (en) * | 1994-03-25 | 1998-05-12 | Siemens Aktiengesellschaft | Combined feed and mixing device |
CN1043612C (en) * | 1994-03-25 | 1999-06-16 | 西门子公司 | Combined feed and mixing installation |
US10722860B2 (en) | 2013-01-15 | 2020-07-28 | The University Of Nottingham | Mixing reactor and related process |
Also Published As
Publication number | Publication date |
---|---|
ES8604031A1 (en) | 1986-01-16 |
DK278285D0 (en) | 1985-06-19 |
BR8502924A (en) | 1986-03-04 |
JPS6146229A (en) | 1986-03-06 |
ES544361A0 (en) | 1986-01-16 |
DE3575680D1 (en) | 1990-03-08 |
CA1262722A (en) | 1989-11-07 |
EP0167060B1 (en) | 1990-01-31 |
DK278285A (en) | 1985-12-21 |
KR860000446A (en) | 1986-01-28 |
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