JP2802129B2 - Solid-liquid separation method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a solid phase separation method for a soluble solid-liquid mixture, and more particularly to a solid-liquid mixture containing a soluble solid phase. To a solid-liquid separation method.

(Prior Art) Solid-liquid mixtures in which solid components are dissolved or precipitated by changes in temperature or solid component concentration, that is, solid-liquid mixtures containing soluble solid components (hereinafter referred to as soluble Solid-liquid mixtures) and those in which the solid component does not dissolve and precipitate (hereinafter referred to as insoluble solid-liquid mixtures). For example, a solid-liquid mixture obtained by the cooling crystallization method corresponds to the former, and sludge water corresponds to the latter. The present invention is directed to the former soluble solid-liquid mixture.

Conventionally, solid-liquid separation for this soluble solid-liquid mixture
It is performed by a vacuum filtration method using a vacuum filter or a centrifugal separation method using a centrifuge.

(Problem to be Solved by the Invention) When the solid-liquid separation is performed by the vacuum filtration method or the centrifugal separation method, the solid phase component in the solid-liquid mixture becomes a cake-like solid (hereinafter, referred to as a cake) and is separated from the liquid. It is obtained. However, during the solid-liquid separation, the liquid is easily trapped between the solid particles, so that a relatively large amount of liquid remains in the cake. This liquid contains a large amount of components other than solid components. Therefore, the solid-liquid separation method using the vacuum filtration method or the centrifugal separation method has a drawback that the purity of the cake is low.

Therefore, in order to improve the purity of the cake, the solid-liquid separation of the soluble solid-liquid mixture was examined in various ways.
When solid-liquid separation is performed using a tubular pressure filter, the liquid is hardly trapped between the solid particles, and the content of the liquid in the cake (hereinafter referred to as the liquid content) can be reliably reduced as described below. I understood.

That is, a tubular pressure filter, which is conventionally used for solid-liquid separation of an insoluble solid-liquid mixture such as sludge water, is used. A soluble solid-liquid mixture is supplied to an annular inner chamber formed between the impermeable membrane and an outer chamber (an annular outer chamber formed between the impermeable membrane and the outer tubular body). A pressurized fluid is introduced to pressurize the solid-liquid mixture in the inner chamber, and the liquid in the solid-liquid mixture is discharged from the pores through the filter medium, and a solid phase cake is formed on the filter medium. , The pressurized fluid is withdrawn from the outer chamber, then the inner tubular body is lowered, air is blown out from the small holes of the tubular body, and the cake is peeled from the filter medium and simultaneously destroyed, and the inner chamber is dropped. Was taken out of the cake.
After the removal of the cake, the above-described steps from supply of the solid-liquid mixture to removal of the cake were repeated. As a result, it was confirmed that the liquid content of the cake could be extremely reduced.

However, when the adhesiveness of the cake formed on the filter medium is high, the cake has a large adhesive force with the filter medium and is difficult to peel off from the filter medium. Therefore, even if air is blown out from the small holes as described above, There is a problem that the cake is likely to remain in close contact with the filter medium and that little or no cake can be taken out from the inner chamber. This is a serious problem that leads to reduced cake productivity.

The present invention has been made in view of such circumstances, and its purpose is to solve the above-mentioned problems relating to solid-liquid separation of a soluble solid-liquid mixture, and to perform vacuum filtration or centrifugation. Compared with the conventional method of solid-liquid separation of a soluble solid-liquid mixture, the purity of the cake can be increased, and even if the cake formed on the filter medium has high tackiness, the cake can be almost or completely removed. An object of the present invention is to provide a method for separating a solid-liquid mixture into solid phases.

(Means for Solving the Problems) In order to achieve the above object, a solid-liquid separation method for a soluble solid-liquid mixture according to the present invention has the following configuration.

That is, the solid phase separation method for a soluble solid-liquid mixture according to claim 1 cools and crystallizes a stock solution to be treated, and crystallizes a specific component in the stock solution to form a soluble solid-liquid mixture. The soluble solid-liquid mixture is supplied to a pressurizing chamber formed of a filter medium and an impermeable membrane, and the crystallized substance is separated by filtration under pressure, and the surface of the crystallized substance adhered to the filter medium is heated. (1st invention). A method for separating a soluble solid-liquid mixture by solid phase separation, wherein the solid phase is dissolved and peeled off and the crystallized substance is discharged.

The solid-liquid separation method for a soluble solid-liquid mixture according to claim 2, wherein the raw solution to be treated is cooled and crystallized to form a soluble solid-liquid mixture, and the soluble solid-liquid mixture is formed into a large number of peripheral walls. Supply to an annular inner chamber formed between an inner tubular body having a through hole and an outer peripheral surface covered with a filtering material and an elastic impermeable membrane, and then supplying the impervious membrane and the outer tubular body with each other. A pressurized fluid is introduced into the annular outer chamber formed between the inner chamber to pressurize the soluble solid-liquid mixture in the inner chamber, and the liquid component in the soluble solid-liquid mixture is discharged through the filter medium. After the solid phase is deposited on the filter medium by filtration and the outer chamber is depressurized, the surface attached to the filter medium of the external solid phase is heated and melted, and the solid phase is separated from the filter medium and discharged. (A second aspect of the present invention).

(Operation) The present invention relates to a method for solid phase separation of a soluble solid-liquid mixture, in which the method for solid phase separation of a soluble solid-liquid mixture according to the first invention is, as described above, The undiluted solution is cooled and crystallized to crystallize specific components in the undiluted solution to form a soluble solid-liquid mixture, and the soluble solid-liquid mixture is supplied to a pressurized chamber formed by a filter medium and an impermeable membrane. The crystallized substance is separated by filtration under pressure, and the surface of the crystallized substance adhered to the filter material is heated and dissolved to peel off, and the crystallized substance is discharged.

As described above, when the crystallized substance (cake) on the filter medium is taken out, the surface of the cake adhered to the filter medium is heated and melted, and the cake is released from the filter medium and peeled off from the filter medium. And may drain the cake.

Therefore, the solid-phase separation method for a soluble solid-liquid mixture according to the first invention can provide a cake (crystallized product) formed on a filter medium having a high adhesiveness and a high adhesive force with the filter medium. As described above, the cake can be peeled off from the filter medium and discharged, so that the cake (crystallized product) can be almost or completely removed. Since the portion of the dissolved cake surface layer can be recovered as a liquid, the dissolution of the cake surface layer does not reduce the product yield.
In the method for separating a solid phase from a soluble solid-liquid mixture according to the first aspect of the present invention, since the crystallized product is separated by filtration under pressure, the liquid content of the cake can be surely reduced and the cake purity can be improved.

The solid phase separation method for a soluble solid-liquid mixture according to the second invention is, as described above, cooling and crystallizing the untreated solution to form a soluble solid-liquid mixture, and forming the soluble solid-liquid mixture into a solid-liquid mixture. The soluble solid-liquid mixture is supplied to the inner chamber of the tubular pressure filter, and then the soluble solid-liquid mixture is pressurized by the pressurized fluid in the outer chamber, and the liquid component in the soluble solid-liquid mixture is discharged through a filter medium. After the solid phase component is deposited on the filter material by filtration and the outer chamber is depressurized, the surface attached to the filter material for the solid phase component is heated and dissolved to peel off the solid phase component from the filter material, I try to discharge.

As described above, when the solid component (cake) deposited on the filter medium is taken out and the surface of the cake adhered to the filter medium is heated and melted, the cake is loosened from the filter medium and separated from the filter medium. And the cake can be drained.

Therefore, the method for separating a solid phase from a soluble solid-liquid mixture according to the second aspect of the present invention, even when the cake formed on the filter medium has a high adhesiveness and a high adhesive force with the filter medium, the cake is separated from the filter medium. It can be peeled off and drained, so that the cake (solids or crystallization) can be almost or completely removed. In addition, since the solid-liquid separation method of the soluble solid-liquid mixture according to the second invention is a solid-liquid separation method using a tubular pressure filter, the liquid content of the cake can be reliably reduced, and the cake purity can be improved. .

As a method of heating and dissolving the surface of the cake adhering to the filter medium, after depressurizing the outer chamber (after extracting the pressurized fluid)
Preferably, a method of heating the inner tubular body is used. In this case, the surface of the cake adhering to the filter medium (cake surface layer) is heated by heat conduction from the heated inner tubular body, and is reliably dissolved. At this time, if the inner tubular body is heated uniformly, the entire surface of the tight contact portion with the filter material can be dissolved, and as a result, the cake can be more completely taken out.

When the heating of the inner tubular body is started before depressurization of the outer chamber (before withdrawal of the pressurized fluid, that is, under pressurization of the inner chamber), the heating dissolves the cake surface layer and is discharged from the inner chamber. Since there is a possibility, the heating is desirably performed after depressurizing the chamber.

Example 1 Example 1 FIG. 1 shows a schematic diagram (side sectional view) of a solid-liquid separation device according to Example 1. This apparatus is obtained by adding a heating means (16) for an inner tubular body to a conventional tubular pressure filter (6).

The tubular pressure filter (6) includes an inner tubular body (7),
Filtering material (8), outer tubular body (9), elastic impermeable membrane (10), pressurizing means (13), and raw material supply means (14)
And means (not shown) for axially driving the inner tubular body (7), and an outer chamber (11) is formed between the impermeable membrane (10) and the outer tubular body (9). And impermeable membrane (10)
An inner chamber (12) is formed between the filter medium (8).

A flow path (not shown) for the heat exchange medium is provided in the peripheral wall of the inner tubular body (7).

The heating means (16) for the inner tubular body comprises: the above-mentioned flow path; a thermostat (18) pipe-connected to the inlet (i) of the flow path via a valve (15) and a pump (17); It comprises a pipe (19) provided between (18) and the outlet (o) of the flow path, and forms a circulation circuit of the heat exchange medium. The heat exchange medium is heated and adjusted to 60 ° C. in the thermostat (18), and when the valve (15) is opened and the pump (17) is operated, the medium circulates through the circulation circuit, and the inner tubular body (7) is circulated. Heat.

First, a solution containing 65% of P-cresol and 35% of m-cresol was cooled to 3.6 ° C., and cooled and crystallized for the purpose of crystallizing P-cresol. (Raw material for liquid separation).

Next, the above-mentioned raw materials were maintained at 3.6 ° C. and the inner chamber (1
2). Immediately thereafter, a pressurized fluid was introduced into the outer chamber (11), the solid-liquid mixture in the inner chamber (12) was pressurized, and the liquid was discharged to form a cake. The cake has extremely high tackiness.

Subsequently, after the pressurized fluid is extracted from the outer chamber (11), the inner tubular body (7) is lowered, and the valve (15) of the heating means (16) of the inner tubular body is opened, and the pump (17) is turned on. Activate,
The heat exchange medium adjusted to 60 ° C. was circulated through the circulation circuit to flow, and the inner tubular body (7) was heated for 15 seconds. The heating time is a heating time required for dissolving the entire surface of the cake in close contact with the filter medium (8), and was previously determined by a test.

Subsequently, when air was blown out from the small holes (5) of the inner tubular body (7), the cake fell while breaking, and the cake could be completely removed from the inner chamber (12). That is, no cake remained on the filter medium (8), and the portion of the cake surface layer dissolved by heating the inner tubular body (7) could be recovered as a liquid.

After the above-described cake removal, the same steps from the raw material supply to the cake removal as described above were repeated. As a result, it was confirmed that the cake could always be completely removed from the inner chamber (12).

Percentage of P-cresol in cake (ie cake purity)
Was 92.0%. The yield of cake (P-cresol) was 13.6%.

Comparative Example 1 FIG. 2 shows a schematic diagram (side sectional view) of a solid-liquid separation device according to Comparative Example 1. The apparatus comprises means for heating the inner tubular body (1
The other points are the same as those of the first embodiment except that 6) is not attached. That is, a conventional tubular pressure filter was used.

The same raw material for solid-liquid separation as in Example 1 was supplied to the inner chamber (12) while being maintained at 3.6 ° C., and the same separation operation as in Example 1 was performed. A cake was formed.

After the formation of the cake, the pressurized fluid was withdrawn from the outer chamber (11), and then the inner tubular body (7) was lowered, and then air was ejected from the small holes (5) of the inner tubular body (7). The filter material (8) was partially peeled off, destroyed and dropped, but most of the cake remained in close contact with the filter material (8), and the cake remained in the inner chamber (12). Could not take out.

(Effect of the Invention) According to the solid-phase separation method for a soluble solid-liquid mixture according to the present invention, a solid-liquid separation method using a tubular pressure filter is used for solid-phase separation of a soluble solid-liquid mixture. And so on, so that not only can the cake purity be increased as compared with the conventional vacuum filtration method and centrifugal separation method, but also the cake formed on the filter medium. Even if the stickiness is high, the cake can be taken out almost or completely, so that a high level of cake productivity can be secured.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing an outline of a solid-liquid separation device according to Example 1, and FIG. 2 is a side sectional view showing an outline of a solid-liquid separation device according to Comparative Example 1. (5) ... small holes in the inner tubular body, (6) ... tubular pressure filter, (7) ... inner tubular body, (8) ... filter material, (9)
... outer tubular body, (10) ... elastic impermeable membrane, (11) ...
... Outer chamber, (12) ... Inner chamber, (13) ... Pressurizing means, (14)
... raw material supply means, (15) ... valve, (16) ... heating means for the inner tubular body, (17) ... pump, (18) ... constant temperature bath,
(19) ... tube, (i) ... inlet of heat exchange medium flow path,
(O) ... outlet of the heat exchange medium flow path.

Continued on the front page (72) Inventor Shingo Yoshida 2-3-1 Shinohara Aunto Noyama-cho, Nada-ku, Kobe-shi, Hyogo (72) Inventor Koichi Nagaoka 1-1-9-303, Ichinoya-cho, Suma-ku, Kobe, Hyogo (56) References JP-A-53-104476 (JP, A) JP-A-63-273093 (JP, A) JP-A-57-190617 (JP, A) JP-A-62-178553 (JP, A) 54-157773 (JP, A) JP-A-54-52678 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B01D 29/01 B01D 29/62 B01D 29/84 B01D 9 / 02

Claims (2)

(57) [Claims] 1. A stock solution to be treated is cooled and crystallized, and a specific component in the stock solution is crystallized to form a soluble solid-liquid mixture. An outer soluble solid-liquid mixture is formed by a filter medium and an impermeable membrane. And pressurized to separate the crystallized product by filtration, and heat and melt the exfoliated surface of the crystallized material to adhere to the filter medium, peel off the crystallized product, and discharge the crystallized product. A solid-phase separation method for a soluble solid-liquid mixture. 2. A solution to be treated is cooled and crystallized to form a soluble solid-liquid mixture, and the soluble solid-liquid mixture is provided with a large number of small through-holes on the peripheral wall and the outer peripheral surface is covered with a filtering material. To the annular inner chamber formed between the inner tubular body and the elastic impervious membrane, and then pressurized fluid to the annular outer chamber formed between the impermeable membrane and the outer tubular body. Introduce and pressurize the soluble solid-liquid mixture in the inner chamber, discharge the liquid component in the soluble solid-liquid mixture through the filter material, filter and deposit the solid phase component on the filter material, After the pressure is released, the solid phase component of the soluble solid-liquid mixture is heated and dissolved by heating the surface of the solid component adhering to the filter medium, and the solid phase component is separated from the filter medium and discharged. Minute separation method.