JPH11221453A - Method and apparatus for preparing homogeneous mixture continuously - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a homogeneous mixture continuously from first and second fluid bodies or solid components by using a tubular reactor equipped with one or more flow rate restricting members opened automatically when a flow rate is increased to enlarge the cross-sectional area of the reactor. SOLUTION: From a storage tank 1 having an agitator 2, a first fluid mixing component such as a polymer dispersion is supplied to a reactor 5, equipped with shell rings arranged continuously, flow restricting members, and a nozzle ring having three groove holes twisted mutually at 60 deg., by a pump 4 through a conduit 3. To the reactor 5, a second mixing component such as a mixing agent is distributed/supplied over the whole length of the reactor by the pump 4 from an agitation storage tank 7 through a conduit 8. Local high density is avoided here, and the mixture of the first and second components with improved mixing quality is prepared. The obtained mixture is supplied to a second storage tank 6 or circulated/returned to the tank 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a first fluid mixed component,
The present invention relates to a method and an apparatus for continuously producing a homogeneous composition from one or more kinds of fluid or solid components.

[0002]

BACKGROUND OF THE INVENTION Mixing is a process commonly performed in the chemical arts field. The fluid mixture component is usually
The mixing is carried out in a stirred tank or optionally by gas circulation in the tank or by forced flow in a conduit. This effect can occur in both turbulent and shear flow. Mixing is used to produce an object by a chemical reaction or to finalize the object, i.e., convert it to a suitable commercial form, but mixing is extremely difficult due to the chemical reaction itself. is important.

The general target state of distribution or distribution is high homogeneity (dissipative mixing).
ing) or at least a homogeneous distribution (dispersive mixing) (d
is permissive mixing). Known mixing devices for liquids are, for example, stirred tanks or tubes, but the homogeneity of the mixture achieved is often unsatisfactory. This is especially the case if the other component to be mixed with the fluid is of a relatively high viscosity, or the viscosities of the two are significantly different.

[0004] For example, a problem arises when treating a polymer dispersion by mixing a generally liquid additive so as to be suitable for various fields. This type of treatment is known as mixing a polymer dispersion.

A common technique for adding admixtures to polymer dispersions is to stir the dispersion in a stirred tank and add the admixture directly to the stirred tank. However, this type of technique often forms coagulum,
Another disadvantage is that the stability of the product mixture is not good.
The economic disadvantage of agglomerates is that not only the high costs required for filtration, but also the expensive admixture is trapped in the dispersion and the admixture must be replenished one after another.

To avoid this drawback, attempts have also been made to add the admixture in diluted form or in small portions, but this leads to a long, uneconomical residence time in the mixing tank.

[0007] In order to eliminate this long occupation of the uneconomical mixing tank, a continuous dispersion method (through-flow mixing method) has been proposed.
(1977) 17, pages 289-295. This continuous dispersion process involves dispersing a polymer dispersion from a first tank via a conduit having a pump and a mixing device to a second tank.
This is a method of transporting to a tank. A feed conduit is provided between the pump and the mixing device, through which the admixture is continuously fed from the storage container. The disadvantage of this method is that it firstly requires a second container for containing the mixture of the polymer dispersion and the admixture, and
In particular, the quality of the mixed polymer dispersion mixture is often unsuitable. As a mixing device for the continuous dispersion method, a static mixing device is generally used. As a result, solid components such as a dispersion film are deposited on the inner wall of the mixing device. Is disadvantageous in that it takes a long time to remove and purify it.

[0008]

The problem to be solved in this technical field or the object of the present invention can be implemented by a simple apparatus and is an economical method capable of providing a composition in a good mixed state. And an apparatus for performing this.

[0009]

SUMMARY OF THE INVENTION However, the above-mentioned problem or object is to continuously and homogeneously form a first fluid mixture component and one or more second fluid or solid components. It has been found by the inventors that this can be achieved by a method of preparing a suitable composition. This method uses a tubular reactor with one or more flow restrictors that automatically increases the reactor cross-sectional area as the flow rate increases.

[0010] The term "fluid" means a state in which a shear force cannot be resisted for a long time. Gases are elastic fluids, and liquids are inelastic fluids (1987, McGraw-Hill, Grant and Hank, The Chemical Dictionary, No. 4).
Edition, p. 239).

The process of the present invention employs a tubular reactor having one or more flow restrictors which automatically increases the reactor cross-sectional area as the flow rate increases.

The term tubular here means an elongated structure having any cross-sectional shape, for example, circular, elliptical or polygonal.

The tubular reactor used in the method of the present invention is described, for example, in West Patent Application No. 4439311. It preferably consists of a metal baffle which is reversibly bent by the incoming suspension and is divided in several parts by slots. The above-described slots begin in the center of the baffle and extend radially outward. A characteristic of such reactors is the low, linear dependence of the pressure drop on the flow volume in the reactor.

The first mixed component suitable for use in the process according to the invention is all fluids, in particular liquids. This fluid mixture constitutes the main flow stream to the flow restrictor in the reactor. To this main stream, further, i.e. a second, mixed component is added, preferably in a smaller amount than the first mixed component. It may be liquid or solid.

In the method of the present invention, the flow rate of the first mixed composition is
Due to the low dependence of the pressure drop on the flow rate, it is suitable for mixing processes where it is variable.

The advantages of the process according to the invention are evident when using mixed components which differ significantly in viscosity and / or flow rate.

Known as mixing of polymer dispersions,
Certain mixing problems arise in connection with the various compositions of polymer dispersions for various end uses.

The polymer dispersion has a continuous phase (dispersion medium, liquid, often water) and at least one discontinuous phase (dispersed phase, polymer). Polymer dispersions are generally described in US Pat. No. 2,754,280, European Patent Application 3
7923, 65253, West Germany 3543361
As described in JP-A Nos. 37-186060, a monomer is prepared by adding a dispersing aid and subjecting the monomer to emulsion polymerization, dispersion polymerization or suspension polymerization. The components to be added as a second mixed component to the polymer dispersion include admixtures, ie, conventional liquid additives for adapting the dispersion to various uses. Examples of such admixtures include preservatives (bactericides) to prevent entry by bacteria and fungi, film forming aids to prepare coating compositions, leveling agents, treatment of natural or synthetic resin emulsifiers. Examples include an antifoaming agent for preventing the formation of bubbles therebetween, and a tackifier added to the pressure-sensitive adhesive.

Examples of admixtures used include sodium salt of 1,2-benzisothiazolin-3-one in a mixture of water and propylene glycol (ICI Pro
xel® XL2), isothiazolone as an insecticidal, herbicidal preparation (Aktiz from ThorChemie)
id (R) LA, K from Rohm & Haas
athon (registered trademark) LX). Still other admixtures include diols such as butyl glycol, butyl diglycol, diethylene glycol, and alcohols such as ethanol, isopropanol, octadecanol. Further, as admixtures from BASF, complexing agents based on ethylenediaminetetraacetic acid, such as solvents such as Lusolvan® FBH, Trilon® B, Lutonal
Aqueous solution of polyvinyl methyl ether such as ® M40, ammonium polyacrylate solution such as Collacral ® P, Polatinol
Anionic dispersions of plasticizers, such as C® (dibutyl phthalate), and montan ester waxes, such as Gleitmitteldispersion® 8645. Still other admixtures include urea and ethylene urea, sodium hydroxide solution,
Potassium hydroxide solution, ammonia, calcium hydroxide, zinc nitrate, zinc oxide, emulsifier such as BA
Block copolymers based on alkylphenol ethoxylates, propylene oxide and ethylene oxide, such as Emulgator® 825 from SF, ie, Dapro from Krahn Chemie
l (registered trademark) DF900, BYK (registered trademark) 033 of BYK-Chemie, Nopc of Henkel
o (registered trademark) 8034E / D, furthermore, benzophenone, solvent (white spirit, acetone), polyvinyl alcohol, modified rosin such as He
Tacolyn (R) 317 from rcules
9. Alliance Technical Prod
octs (ATP) Permatac®
A751, Snowcoc from AkzoNabel.

The admixtures are used in amounts of up to about 20% by weight, in particular up to 50% by weight, based in each case on the polymer dispersion.

The admixture can be metered into a polymer dispersion having a conversion of at least 99%, or a polymer dispersion having a conversion of 80 to 99%.

The process according to the invention is also particularly suitable for treating mixed components which react chemically with one another.

Accordingly, the process of the present invention can be advantageously used to neutralize treated water and wastewater containing alkaline solids with carbon dioxide.

In a conventional method, carbon dioxide is metered into a pipe via a nozzle. A static mixer downstream from this feed position may be able to reduce the required reaction zone length. However, in the case of wastewater in the papermaking, pulp and textile industries, the use of static mixers is unsuitable because of the clogging of the fiber components contained therein.

On the other hand, in the case of the tubular reactor used in the method of the present invention, the carbon dioxide is metered in and the neutralization reaction is carried out with a short pipe length even if a fibrous component is contained. Can be No clogging due to fibrous components in the wastewater.

The device according to the invention comprises a tubular reactor in which one or more (preferably 3 to 12), in each case a unit consisting of a shell ring and a flow restricting member, in particular a baffle plate, are arranged in series. Be the basis. The flow restrictors or baffles move automatically as the flow rate increases to increase the cross-sectional area of the tubular reactor. Another feature of the apparatus of the present invention is that a plurality of perforated holes are arranged alternately in the longitudinal direction of the reactor, and are particularly opened by two adjacent flow restricting members or baffles. The two pores are twisted with respect to each other. The asymmetrical form of the baffles diverts the flowing mixture (especially in the case of highly viscous mixtures) and increases the quality of the mixture.

Yet another morphological feature is that each of the shell rings and one of the flow restriction members, in particular at least one unit having a baffle plate, are connected to the nozzle ring upstream of the latter. 2) is provided. The nozzle ring has the same inner diameter as the shell ring, and is preferably provided with a single or a plurality of holes for feeding a fluid or solid mixed component to the synthetic resin dispersion. . The tubular reactor is made of metal, in particular, for example, 1.45
41 or 1.4571 stainless steel, or P
It is preferably formed from a plastic such as VC. The inner peripheral surface may be coated with rubber or polymer, especially Teflon. Also, the diameter of the tubular reactor depends on the flow rate of the mixture, and the conventional 25, 50, 8
It can be 0, 100, 150 or 200 mm.

The flow restricting member or the baffle is also preferably made of stainless steel.
The inner surface is coated with rubber, plastic, and especially Teflon.

[0029] A nozzle ring, also preferably formed of stainless steel, has another second mixed component:
It is arranged to be able to be fed in a main flow stream, for example a polymer dispersion stream, from a coaxial annular chamber through one or more, preferably three, slots drilled therein. . These slots are between 10 and 90 relative to the reactor longitudinal axis.
°, preferably at an angle of 45 to 90 ° and / or 0 to 90 ° relative to the reactor radius, especially 5 to 45 °
Preferably, they are arranged at an angle of °.

In the following, the invention will be described more specifically, but exemplarily, with reference to the embodiments shown in the accompanying drawings.

In the embodiment of the invention schematically shown in FIG. 1, a first fluid mixture, for example a polymer dispersion, is supplied from a reservoir having a stirrer 2 by a pump 4 to a conduit 3.
And fed to the reactor 5. The reactor has a continuously arranged shell ring and a flow restricting member. The fluid first component is now fed to the second storage tank 6 or circulated back to the original storage tank 1. Furthermore, a second mixed component, for example a mixture, is fed from the stirred tank 7 by means of the pump 4 immediately upstream of the reactor 5 via the conduit 8 to the reactor 5 and / or Distributed over the entire length. The feed of the second mixed composition to the reactor 5 is advantageously carried out via a nozzle ring, which is shown in FIG. 2 and is preferably provided upstream of the flow restricting member of the reactor 5. As the pump 4, a pump commonly used in the chemical industry, for example, a hose pump, a compressed air thin film pump, an eccentric screw can be used, but a non-pulse pump such as an eccentric screw pump having a periodic control drive device or a gear pump is used. Is preferred.

The stirrer 2 used in the storage tanks 1, 6 and 7 may be a conventional anchor propeller, MIG or blade stirrer.

The feeding of the second mixed component divided into a plurality of sections along the longitudinal direction of the tubular reactor 5 avoids local high density, and is, for example, added to the polymer dispersion. In order to improve the quality of mixing by reducing or avoiding the formation of agglomerates during the mixing process. It is particularly preferred for this reason that a nozzle ring (FIG. 2) having three mutually twisted slots 22 (FIG. 2) is provided on the shell ring and the flow restricting member.

The modular construction of the reactor, consisting of a continuous shell ring and flow restrictors, in particular baffles, provides a high degree of flexibility for different end uses, especially for different viscosities and flow rates. Similarly, the number and thickness of the baffles can be adapted to the properties of the mixed composition to be fed, especially its viscosity and flow rate. The baffles can be easily removed, cleaned, or replaced.

The reactor 5 is generally at about 10 ° C to 12 ° C.
0 ° C, preferably 20 ° C or more, especially 30 ° C to 60 ° C
Operated at a temperature of

In the method of adding and mixing the mixed components to the polymer dispersion according to the method of the present invention, the admixture is fed undiluted or diluted, successively, or in the case of two or more, as a mixture. The metering is effected by the pump 4 or by a pressure difference in the feed line 8. If a mixture of admixtures should be delivered,
This preferably takes place via the stirrer 2 which is arranged in the feed line 8. Examples of admixture mixtures include a mixture of a film-forming aid and an antifoaming agent. In the case of an additional stirrer 2 of this kind, it is necessary that a plurality of mixable admixtures be metered from the same reservoir. In this case, the storage tank 7 needs to be provided with a stirrer.

In the course of the process according to the invention, it is necessary to maintain a minimum flow rate in the polymer dispersion feed conduit 3, which is a measure of the coagulation in the polymer dispersion to which the admixture has been added. The percentage is a preset 0.1% by weight,
It is preferably ensured by not exceeding the level of 0.01% by weight. The proportion of coagulum is DIN 53
786. If this becomes excessive, the flow rate of the polymer dispersion is increased by increasing the pumping action of the pump 4. However, there is an upper limit. This is because shearing action can cause agglomeration.

In order to avoid foaming in the course of the addition and mixing treatment, it is advantageous that the stirring in the stirring storage tank 1 is performed under sub-atmospheric pressure.

The feed line 3 for the polymer dispersion and / or the feed line 8 for the admixture may be provided with a pH measuring device and / or a viscosity measuring device.

The nozzle ring shown in FIG. 2 has a hollow annular chamber 21 in which three slots are provided for feeding the admixture or mixed composition to the polymer dispersion or main flow stream. Has been drilled.

[0041]

[Method Examples] In the following examples, the amount ratio of coagulum is
It was determined by filtration according to DIN 53786. That is,
1 kg of the mixture prepared in each Example was filtered through a sieve having a mesh size of 0.125 mm. The residue was washed with demineralized water, dried and weighed. The amount ratio of the coagulum is indicated by% by weight based on the dispersion to which the admixture is added and mixed.

Example 1 (Coloring of Luviskol® solution) In order to evaluate the quality of the mixture according to the method of the present invention, it has about 1000 mPas, which is approximately the same as the actual polymer dispersion, but is a transparent molar substance, ie Luviskol® K90
To a 0.95% concentration solution of (BASF), a 1% concentration solution of an oxazine dye of BASF, Basilen (registered trademark) Blue was added and mixed. The reactor 5 has a diameter of 2
A 0 mm, tubular reactor with four symmetrical mixing baffles was used, and the dye solution was metered in via a nozzle ring with three symmetrical nozzles.

The mixing ratio of Luviskol® to the dye solution was 10: 1.
The flow rate of (registered trademark) was 0.25 m ³ / h.

The homogeneity (σ / x) of the product mixture is 0.24
Met.

Example 1 except that a tubular reactor without a flow restricting member was used instead of a tubular reactor with a comparative C1 mixing baffle.
The same treatment was repeated.

The homogeneity of the product mixture showed a very poor value of 0.97.

Example 2 Addition of admixture to polymer suspension for coating agent according to the method of the present invention Mixing 49.2% by weight of n-butyl acrylate, 45.4% by weight of styrene, 2.9% by weight Of acrylamide and 2.5% by weight of acrylic acid
10 kg of the aqueous dispersion contained was transported from the stirring storage tank to the other storage tank in one hour by a hose pump through a tubular reactor 5 having an inner diameter of 20 mm and five mixing baffles. During this transportation, 100 g of butyl diglycol
The mixture was fed and mixed for one hour by a hose pump via a nozzle ring provided upstream of the first mixing baffle plate.

When the filtration residue was measured, the coagulation ratio was 0.006%.

From a storage tank equipped with a comparative C2 blade stirrer, 100 g of butyl diglycol was metered into the polymer dispersion of the above composition over a period of one hour by a hose pump, and stirring was continued for another half hour. .

When the amount of the filtration residue was measured, the coagulation ratio showed a considerably higher ratio of 0.151% as compared with the above-mentioned method of the present invention.

Example 3 Preparation of a Dispersion Mixture 10 kg of a polymer dispersion based on styrene and butyl acrylate, and 10 containing acrylonitrile.
kg of the acrylate dispersion were metered in over a period of 1 hour in a uniform proportion into a tubular reactor having a diameter of 20 mm and equipped with 10 mixing baffles. The two dispersions are respectively placed in the first mixture upstream of the first mixing baffle.
And between the second mixing baffle is added to the main flow stream. In this case, both feed nozzles are staggered by about 180 °. The mixture discharged from the reactor is collected in a non-stirred storage tank.

The homogeneity of the product mixture is determined by comparing its IR spectrum with the IR spectrum of a mixture of the same composition, obtained beforehand by vigorous stirring, and the proportion of coagulum is determined from the filtered residue. Was.

The following table shows the measurement results of the sample taken downstream of the reactor 5 after the lapse of the time shown in the table.

[0054]

[Table 1] This example shows that a homogeneous mixture containing little coagulum was obtained.

Example 4 Neutralization Reaction In a pilot plant, a pH of 11
Alkaline wastewater containing 3 kg / m ² of sodium hydroxide was neutralized with carbon dioxide in a tubular reactor. This vertical reactor is made of acrylic glass,
It has a diameter of 0 mm and has 5 baffles. The pH measurement electrode provided at the reactor outlet is used to measure the pH of the wastewater to be treated.
The values were measured continuously. Carbon dioxide was metered into the reactor by a glass frit upstream of the first baffle. This amount of carbon dioxide is determined by the pH at the reactor outlet.
The value was regulated to be 8. The flow rate of the supplied carbon dioxide gas was approximately 85 l / h (s, t, p). The neutralized wastewater discharged from the reactor did not contain any carbon dioxide gas.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of a device of the present invention.

FIG. 2 is a cross-sectional view of the nozzle ring.

[Explanation of symbols]

1 storage tank 2 stirrer 3 conduit 4 pump 5 reactor 6 second storage tank 7 stirring storage tank 8 feed pipe 21 Coaxial annular chamber 22 ° slot (for feeding the mixed composition to the main flow)

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Gerd, Römer Germany, 67259, Bindersheim, Königsberger, Straße, 1

Claims (10)

[Claims] 1. A method for continuously preparing a homogeneous mixture from a first fluid mixture composition and one or more other fluid or solid compositions, with increasing flow rate and automatic flow. Using a tubular reactor (5) provided with one or more flow rate limiting members, which is opened to increase the reactor cross-sectional area. 2. The method according to claim 1, wherein the flow rate of the first fluid mixture composition varies during the mixing process by a factor of ± 10, in particular a factor of ± 5. 3. The process as claimed in claim 1, wherein the difference in viscosity between the at least two mixed components is greater than 100 mPas. 4. The flow rate ratio of the first fluid mixture composition to another fluid or solid mixture composition is 1
000: 1 to 1: 1, preferably 100: 1 to 1:
1, especially from 5: 1 to 1: 1;
The method according to claim 1. 5. The method according to claim 1, wherein the first fluid mixture is a homogeneous or non-homogeneous liquid, especially a dispersion, especially a polymer dispersion, and the other fluid or solid mixture is homogeneous or non-homogeneous. 5. The method according to claim 1, wherein the method is a non-homogeneous liquid and / or solid and / or gas. 6. The method according to claim 1, wherein the mixed components react chemically with one another. 7. Apparatus for carrying out the method according to claim 1, comprising one or more, preferably from 3 to 12, one shell ring and one flow restricting member. Especially having a continuous unit composed of baffle plates, wherein the flow rate limiting member is automatically opened as the flow rate increases and increases the reactor cross-sectional area,
Apparatus characterized in that the open pores are staggered with respect to the longitudinal axis of the reactor, and the pores opened by the two adjacent flow restrictors are mutually twisted. 8. A shell unit comprising one or more, preferably from 3 to 12, preferably one shell ring and a continuous unit composed of one flow restricting member. A nozzle ring having the same internal diameter as above and provided with one or more, preferably three, slots (22) for delivering a fluid or solid mixture composition, 7. Apparatus for performing the method of any of claims 1 to 6, characterized in that it is provided downstream of said unit bodies, preferably upstream of said fluid flow restricting member. 7 device. 9. The reactor according to claim 1, wherein said slot is at an angle of from 10 to 90 °, in particular from 45 to 85 °, with respect to the longitudinal axis of the reactor and / or with respect to the radius of the reactor. From 9
9. Device according to claim 8, characterized in that it is formed at an angle of 0 [deg.], In particular 5 to 45 [deg.]. 10. The use according to any one of claims 1 to 9 for mixing admixtures into polymer dispersions for coatings and adhesives.