JPS61257212A - Element for coarsening fine liquid drop - Google Patents

Abstract

PURPOSE:To efficiently coarsen fine liquid drops by constituting an element comprising a sheet contg. >=50% fiber having 0.1-10mum single fiber dia., and having 10-70 packing rate and 0.1-70mm thickness. CONSTITUTION:Suitable fiber to be used in a sheet of the element contains >=50wt% single fiber having 0.3-7mum single fiber dia. Suitable packing rate of the fiber is 10-70%, pref. 20-60%. Suitable thickness of the element is >=0.1mm and <=70mm, pref. >=0.2mm and <=50mm. Further, more remarkable coarsening effect may be obtd. by imparting hydrophilic property, etc. to the surface of the material of the element. Fine liquid drops can be coarsened effectively with the above-described element; the coarsening may be possible independently of the affinity of the fine liquid drops to the element.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a coarse graining element.

[Conventional technology]

BACKGROUND OF THE INVENTION Techniques for separating dispersed microdroplets from a dispersion system consisting of two liquids that undergo phase separation are important in industry and are desired in many fields. For example, removal of micro droplets of water dispersed in cutting oils, lubricating oils, organic solvents, removal of micro droplets of oil dispersed in industrial wastewater, removal of micro droplets of oil dispersed in expensive heating media such as dichlorodifluoromethane. The separation of minute droplets, etc., corresponds to this. Several types of separation methods for these minute droplets are known, and coarse particle separation is one of them. This allows the processing liquid to pass through nine elements that have a coarsening function, thereby coalescing the minute droplets in the processing liquid.
After forming large droplets, the droplets are separated from the dispersion medium based on the difference in specific gravity. This method can separate minute droplets using a simple device in a relatively short time and with low energy compared to other separation methods.
This is an industrially advantageous separation method.

Conventionally, as a coarse graining element such as
As seen in JP-A-45242, a fiber body that has an affinity for minute droplets of oil is used, and as seen in JP-A-57-113810, a binder that has an affinity for minute droplets of water is used. The droplets were made coarser by using a fiber structure that was That is, in these elements, the surface of the fibrous structure efficiently adsorbs the emulsion droplets into the element, destroys the emulsion, and then turns the fine droplets into coarse particles. However, these elements have the disadvantage that, for example, lipophilic elements can effectively coarsen only minute lipophilic droplets, and elements that are not extremely lipophilic or hydrophilic have the disadvantage that There are drawbacks such as difficulty in developing the ability to coarsen minute droplets.

[Problem that the invention seeks to solve]

SUMMARY OF THE INVENTION An object of the present invention is to overcome the drawbacks of the prior art as described above and to provide a coarsening element that efficiently coarsens fine droplets dispersed in a dispersion medium.

[Means for solving problems]

The present inventors have discovered that a remarkable coarsening phenomenon occurs when a dispersion system is permeated through a fibrous sheet made of ultrafine threads, and based on this, the present invention has been completed.

The coarse graining element of the present invention has a single fiber diameter of 0.1 to 10
It is characterized by being composed of a fibrous sheet mainly composed of micrometer fibers, with a fiber filling rate of 10 to 70 mm, and a thickness of 0.1 ms or more and 70 mm or less.

In the coarsening element of the present invention, coarsening of fine droplets is observed regardless of the affinity between the fine droplets and the element. It is presumed that the coarse graining is a phenomenon that can only be caused by using ultra-fine threads, which should be distinguished from coarse graining using the affinity between the droplet and the element. This gives rise to the advantage that, for example, just by preparing one coarse-graining element, the dispersed minute droplets can be handled in either case of lipophilicity or non-itability. moreover,
It is also possible to further improve the performance by imparting affinity for microdroplets to the element.

In the present invention, "coarse graining" is usually 0.1 μm to 50 μm.
This refers to the phenomenon in which a minute droplet with a diameter of m becomes a droplet of 0.1- or more. The droplets thus coarsened are easily separated due to the difference in specific gravity between them and the dispersion medium.

The "coarse graining element" as used in the present invention refers to a fibrous sheet that has the function of coarsening minute droplets in the treatment liquid by allowing the treatment liquid to pass through it. The fibrous sheet may be a woven fabric, a knitted fabric, or a nonwoven fabric.

Further, the fibers constituting the fibrous sheet of the present invention are not limited in any way, but include, for example, polyethylene terephthalate, polyethylene terephthalate adipate,
I polyethylene terephthalate sophthalate, polyethylene terephthalate sepacate, polyethylene terephthalate dodecanedioate, ? Fibers of polyester copolymers such as liptylene terephthalate, polyhexamethylene azitzumide, polyhexamethylene decamide,
4-aryamide fibers such as polyhexamethylenedecamide, 1-lyhexamethylenehexamide, pricapramide, polyoctamide, polynonamide, polydecamide, polydodecamide, polytetramid, 1-lyamide/imide fibers, aromatic polyamide fibers, polyesters such as polyparaoxybenzoate Fibers of ether, fibers of helogne-containing polymers such as polyvinyl chloride, polyvinylidene chloride, polyvinylidene fluoride, polytetrafluoroethylene, fibers of polyolefins such as polypropylene and polyethylene,
Examples include natural fibers such as various acrylic fibers, I-rivinyl alcohol fibers, regenerated cellulose, acetate, cotton, linen, silk, and wool. These fibers may be used singly or in combination.

The fibers constituting the coarse graining element of the present invention mainly have a single fiber diameter of 0.1 to 10 μm, and
Mashikuke single fibers are mainly made of fibers with a diameter of 0.3 to 7 μm. "Mainly" means that the weight of the fibers having the above-mentioned single fiber diameter is 50% of the total weight of the fibers constituting the element.
- or more, preferably 70 inches or more.

For example, even in the case of an element obtained by mixing fibers with various diameters using fibers having a uniform diameter in the length direction, 0.
It is sufficient that the weight of fibers having a diameter of 1 to 10 #I is 50% or more. If the zero weight of single fibers having a diameter of 0.1 to 10 is less than 50 cm of the total stack of fibers constituting the element, an element with sufficient coarse graining ability cannot be obtained. Furthermore, elements made of fibers with a fiber diameter exceeding 10 #l cannot provide sufficient coarse graining ability. Furthermore, it is difficult to obtain fibers with a diameter of less than 0.1 μm industrially.

The fiber filling rate is 10-70 inches. "Fiber filling rate" is
The following formula (density of fibrous sheet) am filling * rate (a) = (fiber. true. density) - X100
Defined by When the fiber filling rate is less than 10%, the coarsening ability is low, and the fiber filling rate of the °C coarsening element increases due to the stiffness of the fibers, resulting in a large drop in liquid permeability. Moreover, when it exceeds 70%, industrially usable liquid permeability cannot be obtained in fact. The fiber filling rate is preferably used in the range of 20 to 60 inches.

The thickness of the element is preferably 0.1 to 70, preferably 0.2 to 50.

If the thickness is less than 0.1, the coarse graining ability of the element is insufficient, and if it is 70 or more, the pressure loss during liquid permeation is too large.

Furthermore, the element of the present invention exhibits the ability to coarsen grains regardless of the fiber material that constitutes it, but it is possible to use a hydrophilic or lipophilic material, or An even more significant grain coarsening ability can be obtained by processing the fiber surface with. for example,
For lipophilic minute droplets, it is best to treat them with a fluorine-based fiber such as TheaCF, or a water-resistant finishing agent such as dimethylpolysiloxane or a fluororesin with a 4-fluoroalkyl group. results. Furthermore, for hydrophilic microdroplets, the fiber surface may be treated with a hydrophilic processing agent such as polyvinyl alcohol fiber or polyethylene glycol copolymer.

The fibrous sheet in the present invention is not limited in any way to the liquid permeation method during grain coarsening treatment, and can be used in any form, such as a flat membrane, a cylinder, or a quarter spiral. Furthermore, from the viewpoint of processing efficiency, the fibrous sheet constituting the coarse graining element is preferably used in a bellows shape. In addition, the fibrous sheet is used by stacking one or more sheets K, and the liquid passing method can be any method such as liquid permeation by gravity or liquid permeation by pressure feeding, and is not limited in any way. do not have. The coarsening process is usually completed in one stage, but because the minute droplets are very stable or the droplets are extremely small, 0.1-1 μm, the coarsening process is completed in one stage. If granulation is insufficient, it may be possible to carry out the treatment in multiple stages or in a manner in which the treatment liquid is circulated.

It is possible to use a reinforcing material such as a wire mesh or a fiber structure for the purpose of reinforcing the element of the present invention. In addition, in order to collect dust and the like in the processing liquid, K before processing the processing liquid with the element of the present invention.

It is also possible to place a dust-collecting material as a pre-filter. For example, examples of the pre-filter include a film-like or cotton-like dust-trapping material.

Furthermore, the coarsening element of the present invention can also be incorporated into the process of concentrating and recovering one component from a multi-component system by distillation, and the dispersion system (distilled component or residual component) obtained from the distillation apparatus can be incorporated into the process. It is preferable to subsequently coarsen the particles using the element of the present invention and then perform specific gravity difference separation, as this enables more efficient and highly accurate concentration and recovery.

Furthermore, when recovering a solvent using the activated carbon adsorption method, in order to recover the solvent adsorbed on the activated carbon, steam is blown directly to remove the solvent adsorbed on the activated carbon. It is also possible to separate the particles after coarsening them using a granulating element.

The following is the rest. [Effects of the Invention] The above-mentioned coarsening element makes it possible to effectively coarsen microdroplets, and to do so regardless of the affinity between the microdroplets and the element. It can be coarsened.

〔Example〕

The methods for measuring the moisture and oil concentrations and the method for preparing the liquid to be treated, which will be described in the following examples, are as follows.

(a) Water concentration of sample (ppm) A sample to be measured was collected in a 500-cm beaker, and after standing still for 1 minute, a 2-cm sample was taken from the top and 0.2 + d of ethanol with a known moisture content was added. Thereafter, the water content was measured using MKC-3P (manufactured by Kyoto Denshi Sangyo) by the Karl Fischer method. The formula for calculating water concentration is as follows.

A: Weight of sample 10- CI) B: Weight of ethanol 0.2- (Ii) C: Moisture content in the entire sample + ethanol (, ID: Moisture content in ethanol 0.2- (9) ( b) Oil concentration in the sample (ppm)
Collect the sample to be measured in a 500mm beaker, let it stand for 1 minute, then take a 2cm sample from the top and place it in an oil content analyzer (Oll Content Analyzer).
(manufactured by Horiba) to measure the oil concentration (ppm). Measured values are weight fractions.

(,) Method for preparing treatment liquid 1 B heavy oil was thoroughly mixed with water to obtain a dispersion system having an oil concentration of 250 ppm. It was confirmed using an optical microscope (1,000 times magnification) that the oil droplet diameter was 3 to 5 μm.

(d) Method for preparing treatment liquid 2 1.1.2.2- Add water to tetrachlorethylene,
After heating to 00°C, the mixture was cooled to 20'C in a water bath to obtain a dispersion. The water concentration was 210 ppm. In addition, the diameter of the water droplets was determined to be 2 to 4 μm using an optical microscope (
1,000 times)).

(e) Method for preparing treatment liquid 3 Water and machine oil (Nippon Oil Co., Ltd. Sue 4-Highland)
was added and mixed for 10 seconds using a juicer mixer to obtain a dispersion system with an oil concentration of 310 ppm.

The oil droplet diameter was confirmed to be 2 to 4 μm using an optical microscope (1,000
0x) K and confirmed.

Example 1 A product of the present invention and comparative examples A and BK as shown below were treated with the above-mentioned treatment liquid 1.2.

The product of the present invention was prepared as follows. That is, the diameter of the single fiber obtained by the melt blowing method was 1.7 μm.

A nonwoven sheet made of yje IJ ethylene terephthalate fibers with a thickness of 0.15 cm and a fiber filling rate of 22 cm is
After cutting the tube into a medium cylinder with a height of 100 cm and a diameter of 30 cm (processing liquid was introduced from the bottom).

A coarse graining element was obtained by winding it around the side of a stainless steel wire mesh (with the head and bottom sealed so that the liquid could come out from the exposed side) to a thickness of 1.5 cm.

In addition, the element of Comparative Example A had a single fiber diameter of 14-1
A polypropylene non-woven sheet with a thickness of Q, 5 sw + fiber filling rate of 30% was cut into a width of 100 cm and a length of 283 cm, and then roughly wrapped around the side of the above-mentioned inner cylinder to a thickness of 1.5 m. Granulation elements were obtained.

The element of Comparative Example B consists of fibers 7 with a single fiber diameter of 15 μm.
Made of woven fabric made of plain viscose rayon fibers, fiber filling rate is 50 cm.

One of the products of the present invention was wound around the inner cylinder used in the comparison individual so that the fiber layer thickness was 1.5 cm to obtain a coarse graining element.

These three types of elements perform processing by sending the processing liquid from the inside of the inner cylinder through the side to the outside, and at this time, the liquid was sent under a pressure of 7 kg/an''. The processing solutions 1 and 2 described above were used as the solutions.The results are shown in Table 1.

As shown in Table 1, in the coarse-graining element with oil-producing properties (Comparative Example A), the minute oil droplets are coarsened, but
Micro droplets of water are not coarsened, and in the coarsening element with hydrophilicity (Comparative Example B), microdroplets of water are coarsened, but microdroplets of oil are not coarsened. I understand that.

In contrast, it can be seen that the product of the present invention can coarsen minute droplets regardless of whether they are oil or water.

Table 1 Example 2 Non-woven fabric sheets of polyethylene terephthalate fibers of various fiber diameters were formed to have a fiber filling rate of 20 seconds and a thickness of 1.5 gourds to obtain coarse graining elements. For fibers of 1.2 μm, melt blowing method is used, and for fibers of 3, 8 to 15.5 μm,
The fiber obtained by direct spinning was cut into a length of 51 fil, and then the fiber was obtained by a wet papermaking method. Press these non-woven fabrics.

The thickness was L5. 45 elements obtained in this way
It was attached to a membrane filter holder manufactured by Millipore Co., Ltd., and the liquid was fed at a pressure of 20'q/an'' to perform a coarse particle treatment.The treatment liquid was the above-mentioned treatment liquid 1.The results are shown in the second column.
Shown in the table. This result shows that a fiber element having a single fiber diameter of more than 10 μm cannot sufficiently coarsen the fine droplets.

Table 2 Example 3 A coarse-grained element with a fiber filling rate of 5 to 80 was obtained by pressing a nonwoven sheet using polypropylene fibers having a single fiber diameter of 3 μm obtained by a melt blow method. The press pressure is in the range of 1 to 150 kp/cR'', and in addition, depending on the press temperature and time,
Six types of elements with different fiber filling rates were created. Further, the thickness of the element was set to 10.01 by overlapping elements with the same fiber filling rate. The thus obtained coarse-grained element with a thickness of 10.0-
- Attach it to a Mengren filter holder manufactured by Milliboc Co., Ltd., and perform a coarse particle treatment by passing the treatment liquid 3 at a pressure of 2.0 kll/lx''.9.
Processing speed) to rotameter (maximum measurement value 2000III
g15)). The results are shown in Table 3.

From the results shown in Table 3 below, it can be seen that sufficient coarse graining cannot be achieved with a fiber filling rate of 10 grooves. - Also, when we measured the processing speed, we found that for elements with a fiber filling rate of 70% or less, the processing speed was 300 d/min or more, whereas for an element with a fiber filling rate of 80%, the processing speed was 3635 m/min. It is considered that a fiber filling rate exceeding 20% is of no industrial use value because the processing speed is too slow.

Example 4 After cutting 5 μm nylon-66 fibers obtained by the direct spinning method into 5 lengths, a nonwoven fabric was obtained by the wet papermaking method, and this was pressed to a thickness of 0.05 μm.
m, a nonwoven fabric with a fiber filling rate of 10 cm, and J! J, Mi 0.1
m, a fiber filling rate of 1 (l) was obtained. Thickness: 0.2W
The element was obtained by overlapping two sheets of nonwoven fabric with a thickness of 0.1 square meters. Maku 50, 70, 100m++
For elements with a thickness of 0.0, respectively, the above thickness is 0.
1 m non-woven fabric with a width of 50.70,100 mm and a length of 10 mm
oo■ Prepare.

This was tightly rolled up into a cylindrical shape with a cross-sectional area of 10 cIL", and the sides were sealed with a 3-inch thick urethane resin sheet to prevent liquid leakage. Thickness: 0.05-0.
．． For the 2 van element, use a 45-φ Millipore Menzlen filter holder, and use a 50-1
For the 00■ element, the liquid was fed from one end of the cylindrical element, and the treated liquid was obtained from the other end.

The pressure of liquid feeding was 2.0 kg/cm'' in all cases. Processing liquid 1 was used in the experiment, and the throughput rate was measured in the same manner as in Example 3, and the measured values were calculated based on the cross section in the permeation direction of the processing liquid. The area 1 was converted into the throughput of 1 bento.The results are shown in Table 4.

From the results shown in Table 4 above, if the thickness is less than 0.1, sufficient coarsening ability can no longer be obtained, and if the thickness exceeds 70m5, the pressure loss of the element will cause a sufficient throughput to no longer be obtained. Recognize.

Example 5 Single fiber diameters of 3.2 μm and 17.5 μm obtained by direct spinning method
By cutting 5 m of polyethylene terephthalate fibers into 5 cm lengths, mixing them in various weight fractions, and pressing a nonwoven sheet obtained by a wet papermaking method.

A coarse grained element with a fiber filling rate of 30% and a thickness of 1.0 cm was obtained. A coarsening test was conducted using this element. The test method and treatment liquid were the same as in Example 2. The results are shown in Table 5.

From the above results in Table 5, it is clear that if the weight fraction of fibers with a single fiber diameter exceeding 10 μm is 50% or more, sufficient coarsening will not take place.
．． It can be seen that the filling ratio of fibers of 1 to 10 μm must be 501 or more.

Claims (1)

[Claims] Mainly composed of single fibers with a diameter of 0.1 to 10 μm, a fiber filling rate of 10 to 70%, and a thickness of 0.1 to 70%.
A coarse-grained element consisting of a fibrous sheet of mm.