JPH0113883B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides that the packing frame alternately has corresponding supply and communication perforations for the solution to be treated connected to the interior of the chamber via supply and discharge grooves on opposite side edges. The present invention relates to a diaphragm laminated unit for multi-chamber processing, which has a packing frame, an end plate, and a diaphragm.

The principles of electrodialysis, the diaphragm stack structure for desalting saline solutions using two solution streams, and the basic idea of the packing frame are known from German Patent Application No. 2902247. However, in the diaphragm stack structure proposed in the above publication, useful substances can be obtained from solutions and wastewater under economic conditions, or recovered for reuse or for the purpose of removing environmental pollutants. Circulation cannot be performed. This is because this diaphragm stack unit cannot introduce and discharge more than two types of solution streams, and this is not possible to realize on a simple industrial scale.

Furthermore, experimental devices with individual flow through each chamber are also known. However, each chamber has a thickness of 5 mm, so that if there are a large number of chambers, the dimensions of the diaphragm stack unit will be too large and it will be difficult to install a common inlet and outlet tube.

If up to four independent streams are required to solve a particular problem, the process can be carried out in two sequential steps using two conventional diaphragm stack units connected in series. Although this is possible in some cases, the expense is significantly higher due to the high equipment costs and high energy consumption.

The object of the present invention is to provide a diaphragm stack unit of the type described above, which can be separated in one step and, where appropriate, several components can be changed in solution.
Therefore, it is desirable to configure the device so that it can be used for purposes other than electrodialysis.

This object is achieved according to the invention by the unit according to claim 1.

Advantageous embodiments of the invention are described in the following claims.

One of the most essential advantages of the present invention is that it is possible to prepare a diaphragm stack unit (of which several more may be combined in series), each with its own type of packing frame, turning frame, and end plate. It is possible to carry out separation and conversion tasks requiring mutually independent solution streams up to the species. This makes it possible in particular to remove environmental pollutants from waste liquids such as those produced in the metal surface treatment and chemical treatment industries.

According to the invention, therefore, up to four types of membranes can be separated in one membrane stack unit by combining membranes (cation exchange membrane, anion exchange membrane and neutral membrane) suitably adapted to the process. The ability to flow liquids makes it possible to separate and optionally transform several components dissolved in water in one step. In this case, the mass transport through the diaphragm can take place both simultaneously and individually by electrotransport and diffusion and dialysis.
Special packing frames, end plates and turning plans are also developed to extend the processing run.

Next, the present invention will be explained in detail with reference to FIGS. 1 to 10 by way of embodiments relating to a diaphragm stack unit and its use.

The uniform packing frame used has the construction described in the already mentioned West German Patent Application No. 2902247. The opposite side edges 1 and 2 (FIG. 1) of the square packing frame 3 are provided with a number of slits 4, 5 for supplying and discharging the solution into the chamber 6 surrounded by the packing frame 3. There is. The slits 4, 5 are located opposite each other on the side edges 1, 2. The slits 4, 5 form narrow passages leading into the inside of the packing frame 3, which has a mesh fabric 7 inserted as a diaphragm spacer to be placed on both sides. The channels diverge at a 90° angle, thus creating a zigzag shape at the chamber interface.

The slits 4, 5 are connected to supply and communication boreholes 8, 9. These perforations pass through the packing frame 3 and correspond to the perforations in the diaphragm and end plate. Perforation 8,9
Next to is another supply and communication hole 10,1
1 are provided alternately, the perforations 10, 11 simply passing through the side edges and connecting with the other chambers.

The other opposing side edge 1 of the packing frame 3
2, 13 is another penetrating supply and communication hole 14,
15 and 16, 17, these perforations form supply and discharge conduits for the other solution flow(s) and are arranged in a diaphragm stack unit offset by 90° to 270°. Create a frame. These perforations are connected to slits in other chambers corresponding to slits 4 and 5, respectively.

All perforations and slits 4, 5, 8-11 and 14-17 are connected to each other and to the interior and surroundings of chamber 6 and to the deflection frame (see FIG. 7) by means of packing material coverings 18-20. It is sealed when the end plates are assembled to form the diaphragm stack unit.
The perforations 21 and the gaskets 22 present at the four corners of the gasket frame 3 are used for accommodating the holding material that passes through them.

FIG. 2 shows the three-dimensional arrangement of four packing frames 3. From this drawing it can be seen that the individual supply and communication perforations 8 to 1 in each chamber, as already described.
1, 14 to 17 can be grasped.

FIG. 3 shows one of the two end plates 23 to be used. The end plate has a notch 24 which forms a chamber with the diaphragm in contact therewith. Perforations 25-28 are similarly provided on two mutually adjacent sides, and these correspond to perforations 8-11 and 14-17.

The perforations 25-28 are inclined (see FIG. 4) to form each solution supply and discharge passageway 31-38 (the fifth
(see figure). These solutions are discharged at the surface of the diaphragm stack unit 39 or from the end plate 23 (the packing frame 3 and the diaphragm 40 are shown schematically in FIG. 5).

FIG. 6 shows a chemical reaction mixture containing a nonionic impurity (OV) in addition to an organic acid sodium salt (NaR), which is partitioned by a membrane 40 for removing the impurity, concentrating the salt, and converting it into a free salt. Private room 41~
An example of the use of a diaphragm stack unit 39 having 44 is shown. At least three cation exchange membranes and two anion exchange membranes 40 are arranged alternately in this four-cycle diaphragm stack unit. A four-chamber unit is thus obtained.

These units can be doubled by simply collocating them. 10-100 in practice
A diaphragm stack unit having several parallel units is used.

The four circulation systems were fed with the following solutions via inlets into chambers 41-44:

41-Reaction mixture (containing NaR and non-ionic organic impurity OV), 42-Diluted organic acid, 43-Hydrochloric acid (HCl) 44-Sodium chloride solution (NaCl).

After applying the voltage, the next transport process is carried out in chambers 41 to 44.
arose within.

41 - Sodium ions (Na ⁺ ) and acid residue ions (R ^- ) are introduced into chamber 44 or 42 . The solution is desalted and contains only a small amount of nonionic organic impurities OV that are not transported in the electric field.

42-R ^- ions are introduced into this chamber from chamber 41 and hydrogen ions (H ⁺ ) are introduced from chamber 43. A pure organic acid (HR) is produced which can be further concentrated by partial recirculation (circulation).

43-The acid present in this chamber supplies H ⁺ ions to the acid to be formed in chamber 42. Chloride ions (Cl ⁻ ) are transported to chamber 44 .

44-A concentrated sodium chloride (NaCl) solution is now produced from the Cl ^- ions in chamber 43 and the Na ⁺ ions in the adjacent chamber 41.

The concentration of sodium chloride solution is a constant value (approximately 20%)
shall not exceed. This can be done either by continuous addition of water (optionally the desalted solution from chamber 41 can be utilized) or by discontinuous exchange of the concentrated solution. achieved.

As a result, a desalted solution is obtained in which the purified concentrated organic acid also has concentrated sodium hydrochloride solution and organic impurities as by-products and precipitated products. Other applications of the four-chamber unit include, for example, the after-treatment of saline solutions produced during paper production.

In order to internally divert the solution flow within the diaphragm stack unit, for n solution flows, n+1 impermeable plastic membranes or plates 45 and n placed between them are used.
It is advantageous to extend the process by means of a turning unit (see FIG. 7) constituted by several turning frames 46. In FIG. 7, steps 47 and 48 of two types of solutions are shown.

As the diverting frame 46, frames having the same dimensions as the packing frame 3 but having a larger thickness are used, for example, in the case of two-flow/counter-flow, they are shifted by 180 degrees from each other. The direction change is effected by the solution inlet slit and the outlet slit of the turning frame 46, and also by the two outer sides of the turning unit, which have only through holes in the two adjacent side edges of the square and are arranged 180° displaced from each other. It is controlled by a diaphragm plate 45.

FIG. 8 shows a separation stage A with a permeable diaphragm 49 and a subsequent conversion stage B with an impermeable diaphragm 45 in the case of two-flow/counter-flow. The number of separation stages per stack unit is m+1 for m turning stages B and is adapted to the required process steps. 2 to 200 packskin frames 3 for each tier
can be used.

Internal conversion is possible in an even simpler way.
In this direct diversion plan, the flow direction of the solution stages 47, 48 is reversed within the chambers of two adjacent separation stages A and A' (FIG. 9). Direction change is performed by separation stage A,
This is obtained by providing only two adjacent square edge through-holes between A' and inserting an impermeable plastic diaphragm 50, each placed at an angle of 180° to the nearest one.

Furthermore, it is also possible to use permeable diaphragms instead of impermeable diaphragms. In this case, a laminated unit is obtained which allows electrical transport of ions.

Example of electrolytic double decomposition without significantly affecting the total amount of electrolysis.
Changing the ionic composition of cations and anions in a solution consisting of _CaCl2 . This problem is solved by the three-way embodiment shown in FIG. 10 of the diaphragm stack unit and the repeating diaphragm structure described below.

In this case, the following symbols are used (K: cation exchange membrane, A: anion exchange membrane).

Cation exchange: A, K, K Anion exchange: K, A, A Between the two cation exchange membranes there is a treatment solution whose cation composition is to be changed. When an electric field is applied, cations are transferred from an adjacent donor solution to a treatment solution whose concentration should be increased, and similarly, cations whose concentration must be decreased are transferred from the treatment solution to another adjacent solution (acceptor solution). .

Example of dialysis Acids impure with salts (e.g. corrosive acids or acids resulting from the regeneration of cation exchangers) are purified without actual dilution, using the units shown in Figures 8 or 9. can do.

This problem is solved by the two-component configuration of the membrane stack unit, which allows the process run to be extended by internal diversion of the solution, and by the use of dialysis membranes that permeate acids but retain salts.

Dialysis Process Description Impure acid and water were sent in countercurrents to a membrane stack unit. The acid then diffused into the water through the permeable diaphragm, yielding as product an acid whose concentration was slightly lower than that of the impure acid. Furthermore, an acidic solution of the salt was obtained.

By using a packing frame, an end plate and a turning frame, a diaphragm stack unit is prepared that can solve electrodialysis, electrometathesis and dialysis separation and conversion problems requiring two, three or four solution streams. Depending on the arrangement of the packing frame and the number of solution streams, the flow directions in adjacent chambers can be parallel to each other or offset by 90°.

The conversion plan described above can be developed to obtain a membrane stack unit with an extended treatment stroke that is particularly suitable for dialysis treatment.

[Brief explanation of drawings]

Fig. 1 is a plan view of the packing frame used in the present invention, Fig. 2 is a diagram showing a method of laminating the packing frame, and Fig. 3
The figure is a plan view of the end plate, Figure 4 is a sectional view of the end plate, and Figure 5 is a sectional view of the end plate.
The figure is a schematic diagram of a laminated unit, Figure 6 is a schematic diagram of a four-chamber unit, Figure 7 is a diagram showing the process of two types of solutions, Figure 8 is a diagram showing two-flow/counter-flow, and Figure 9 10 is a diagram showing internal conversion within a laminated unit, and FIG. 10 is a diagram showing an example of electrical double decomposition. 1, 2...Side edge, 3...Packing frame, 4,5
...slit, 6...chamber, 7...reticular fabric, 8,
9, 10, 11...supply and communication drilling, 12, 1
3... Side edge portion, 14, 15, 16, 17... Supply and communication hole, 18, 19, 20... Packing material covering part, 21... Perforation, 22... Packing, 23
... End plate, 24 ... Notch, 25, 26, 27,
28... Perforation, 31-38... Supply and discharge passage, 39... Diaphragm lamination unit, 40... Diaphragm,
41, 42, 43, 44... Private room, 45... Plastic diaphragm or plate, 46... Turning frame, 47, 4
8...Solution process, 49...Permeable diaphragm, 50...
Impermeable plastic septum.

Claims (1)

[Scope of Claims] 1. The packing frame has on opposite side edges corresponding supply and connection perforations for the solution to be treated, which are connected to the interior of the chamber via alternate supply and discharge grooves;
In a diaphragm laminated unit for multi-chamber processing having a packing frame, an end plate, and a diaphragm, (a) another chamber 6,
Further through-feeding and connecting boreholes 14, 17 are provided which alternately connect with the feed and outlet grooves 41-44; (c) Supply and communication perforations 8-11, 14-17 are provided in the square side edges 1, 2, 12, 13, and the packing frame 3 is continuous. A diaphragm laminated unit for multi-chamber processing, characterized in that the diaphragms are arranged in a staggered manner. 2. Use for electrodialysis, electrometathesis and dialysis and combinations thereof, characterized in that the deflection frame is thicker than the packing frame 3 but has the same external dimensions. Units listed. 3. The unit according to claim 1 or 2, wherein all the packing frames 3 have the same structure. 4 Penetrating supply and communication holes 8-11, 14-
4. A unit according to claim 1, characterized in that the parts 17 are sealed to each other and to the environment by layers of packing material 18-20. 5. The flow directions to the adjacent chambers 6, 41 to 44 are parallel to each other or offset by 90° depending on the arrangement of the packing frame 3 and the number of solution flows.
5. A unit according to any one of claims 1 to 4 for use with ~4 solution streams. 6. A unit according to claim 5, characterized in that it is used for removing nonionic impurities consisting of salts containing organic acids, concentrating the salts and converting them into free acids.