EP0167060B1 - Verfahren zum Dispergieren eines Fluidums in ein anderes - Google Patents

Verfahren zum Dispergieren eines Fluidums in ein anderes Download PDF

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Publication number
EP0167060B1
EP0167060B1 EP85107565A EP85107565A EP0167060B1 EP 0167060 B1 EP0167060 B1 EP 0167060B1 EP 85107565 A EP85107565 A EP 85107565A EP 85107565 A EP85107565 A EP 85107565A EP 0167060 B1 EP0167060 B1 EP 0167060B1
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EP
European Patent Office
Prior art keywords
fluid
pipes
streams
pulp
inches
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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 - Lifetime
Application number
EP85107565A
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English (en)
French (fr)
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EP0167060A1 (de
Inventor
Lawrence Marvin Litz
John Joseph Santalone, Jr.
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Union Carbide Corp
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Union Carbide Corp
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Filing date
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Publication of EP0167060A1 publication Critical patent/EP0167060A1/de
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Publication of EP0167060B1 publication Critical patent/EP0167060B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • 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
    • 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.
  • a process for dispersing a gas in a liquid or liquid-solids mixture having a relatively higher viscosity comprising the steps of:
  • 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.
  • a process for dispersing a first fluid in a second fluid having a relatively higher viscosity comprising the following steps:
  • 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 269 streams per m 2 (about 25 streams per square foot) of cross-section of the confined zone to about 10764 streams per m 2 (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 538 to about 6458 per m 2 (about 50 to about 600 streams per square foot).
  • the streams are about equidistant from one another, the distance between streams being about 9.7 to about 64 mm (about 0.375 to about 2.5 inches) and preferably about 12.9 to about 43.9 mm (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 multiplicty 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 100 metric tons of pulp solids per day.
  • the flow rate of the oxygen is about 22.6 to 156 standard m 3 /h (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 25 to about 254 mm (about 1 to about 10 inches) apart, preferably about 76 to about 127 mm (about 3 to about 5 inches) apart.
  • the sets of pipes are spaced apart from one another by about 25 to about 305 mm (about 1 to about 12 inches), preferably about 76 to about 152 mm (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 usually 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.
  • 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 610 mm (24 inch) diameter pipe line, which carries the pulp mass into the bottom of the upflow tower.
  • Pipe 21 is 591 mm (23.25 inches) in inner diameter and is 457 mm (18 inches) long.
  • the small pipes 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 102 mm (four inches) apart.
  • the small pipes are 7.6 mm (0.30 inch) in inner diameter and 13.7 mm (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 thorugh 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 267 mm (10.5 inches) long, the row is only about 165 mm (6.5 inches) long and 51 mm (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 0.64 mm (0.025 inch) and are 76 mm (three inches) apart from adjacent outlet ports 31 in the same row. Thus, if all of the outlet ports 31 in each of small pipes 2 to 15 were in the same row, they would be 38.1 mm (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 is 689 per m 2 (64 per square foot) of cross-section.
  • Oxygen at a pressure of about 929 kPa (120 psig) is introduced through inlet pipe 27 25.4 mm (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 9.5 mm (0.375 inch) thick). The amount of oxygen introduced is 4 kilograms per metric ton of pulp solids.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • Paper (AREA)
  • General Preparation And Processing Of Foods (AREA)

Claims (7)

1. Verfahren zum Dispergieren eines ersten Fluids in einem zweiten Fluid, das eine relativ höhere Viskosität hat, mit den folgenden Verfahrensschritten:
(a) Vorsehen einer begrenzten Zone, die eine Öffnung an ihrem stromaufwärtigen Ende, eine Öffnung an ihrem stromabwärtigen Ende und eine gedachte Mittelachse (29) aufweist, die von dem stromaufwärtigen zu dem stromabwärtigen Ende verläuft;
(b) Einleiten des zweiten Fluids in die begrenzte Zone an der Öffnung in dem stromaufwärtigen Ende derart, daß das zweite Fluid von der Öffnung in dem stromaufwärtigen Ende durch die Öffnung in dem stromabwärtigen Ende strömt;
(c) Unterteilen des ersten Fluids in eine Mehrzahl von Strömen, indem das erste Fluid in eine Reihe von perforierten oder porösen Rohren (1 bis 16) geleitet wird, die in der begrenzten Zone angeordnet sind, und Einleiten der Ströme in daz zweite Fluid im Gleichstrom mit diesem;
dadurch gekennzeichnet, daß das erste Fluid in etwa 269 bis etwa 10 764 Ströme je m2 (etwa 25 bis 1000 Ströme je Quadratfuß) einer zu der Mittelachse (29) senkrechten Querschnittsfläche der begrenzten Zone unterteilt wird, indem es in eine Reihe von 2 bis 6 Gruppen (1,4,7,10,13,16; 2, 5, 8, 11, 14; 3,6,9,12,15) der Rohre (1 bis 16) eingeleitet wird, wobei die Gruppen der Rohre einen näherungsweise gleichen gegenseitigen Abstand von etwa 25 bis etwa 305 mm (etwa 1 bis etwa 12 Zoll) haben, die Rohre innerhalb jeder Gruppe quer zu dem Querschnitt der begrenzten Zone, innerhalb dessen die Gruppe angeordnet ist, einen Abstand von etwa 25 bis etwa 254 mm (etwa 1 bis 10 Zoll) haben und die Rohre in jeder Gruppe versetzt zu den Rohren in den anderen Gruppe angeordnet sind, und wobei die Ströme einen näherungsweise gleichen gegenseitigen Abstand von etwa 9,7 bis etwa 64,5 mm (etwa 0,375 bis etwa 2,5 Zoll) haben.
2. Verfahren nach Anspruch 1, wobei die Anzahl der Ströme im Bereich von etwa 538 bis etwa 6458 je m2 (etwa 50 bis etwa 600 je Quadratfuß) der Querschnittsfläche liegt.
3. Verfahren nach Anspruch 2, wobei der Abstand zwischen den Strömen etwa 12,9 bis etwa 43,9 mm (etwa 0,5 bis etwa 1,7 Zoll) beträgt.
4. Verfahren nach Anspruch 1, wobei das zweite Fluid eine Pulpenmasse in Form eines Gemisches von etwa 10 bis etwa 15 Gewichtsprozent Pulpenfeststoffen und einer alkalinen Lösung als Rest ist.
5. Verfahren nach Anspruch 4, wobei das erste Fluid Sauerstoff ist, der in die Pulpenmasse in einer Menge von etwa 2,5 bis etwa 7,5 Kilogramm Sauerstoff je metrische Tonne an Pulpenfeststoffen eingeleitet wird.
6. Verfahren nach Anspruch 1, wobei die Dispersion aus erstem Fluid und zweiten Fluid stromabwärts von der begrenzten Zone vermischt wird.
7. Verfahren nach Anspruch 6, wobei das Mischen mit einem statischen Mischer erfolgt.
EP85107565A 1984-06-20 1985-06-19 Verfahren zum Dispergieren eines Fluidums in ein anderes Expired - Lifetime EP0167060B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US62245284A 1984-06-20 1984-06-20
US622452 1990-12-05

Publications (2)

Publication Number Publication Date
EP0167060A1 EP0167060A1 (de) 1986-01-08
EP0167060B1 true EP0167060B1 (de) 1990-01-31

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP85107565A Expired - Lifetime EP0167060B1 (de) 1984-06-20 1985-06-19 Verfahren zum Dispergieren eines Fluidums in ein anderes

Country Status (8)

Country Link
EP (1) EP0167060B1 (de)
JP (1) JPS6146229A (de)
KR (1) KR860000446A (de)
BR (1) BR8502924A (de)
CA (1) CA1262722A (de)
DE (1) DE3575680D1 (de)
DK (1) DK278285A (de)
ES (1) ES8604031A1 (de)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4109101A1 (de) * 1991-03-20 1992-09-24 Turbon Tunzini Klimatechnik Einbau fuer mischkammern stroemungstechnischer anlagen
ATE130220T1 (de) * 1991-07-30 1995-12-15 Sulzer Chemtech Ag Einmischvorrichtung kleiner fluidmengen.
KR100339317B1 (ko) * 1994-03-25 2002-11-23 지멘스 악티엔게젤샤프트 조합형공급및혼합장치및그방법
EP2945732B1 (de) 2013-01-15 2019-07-17 The University of Nottingham Mischverfahren

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE386692B (sv) * 1974-03-14 1976-08-16 Sunds Ab Anordning for koncentrering och/eller vetskebehandling sasom tvettning eller blekning av vetskehaltiga emnesblandningar, serskilt cellulosamassa
DE2447369A1 (de) * 1974-10-04 1976-04-22 Basf Ag Verfahren und vorrichtung zum einmischen von niedrigviskosen fluessigkeiten in hochviskose medien
GB1536448A (en) * 1976-06-01 1978-12-20 Emi Ltd Radiography
JPS5939176B2 (ja) * 1976-11-29 1984-09-21 バブコツク日立株式会社 流体注入混合装置
JPS54127064A (en) * 1978-03-06 1979-10-02 Komax Systems Inc Charging instrument of stationary mixer
SE8104198L (sv) * 1981-03-24 1982-09-25 Bergwerksverband Gmbh Anordning for inforande av gas i en vetska eller i en blandning av vetska och fast emne
ZA835925B (en) * 1982-09-30 1984-04-25 Black Clawson Co Method and apparatus for oxygen delignification

Also Published As

Publication number Publication date
KR860000446A (ko) 1986-01-28
DE3575680D1 (de) 1990-03-08
JPS6146229A (ja) 1986-03-06
EP0167060A1 (de) 1986-01-08
CA1262722A (en) 1989-11-07
ES544361A0 (es) 1986-01-16
DK278285A (da) 1985-12-21
BR8502924A (pt) 1986-03-04
DK278285D0 (da) 1985-06-19
ES8604031A1 (es) 1986-01-16

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