RU2115459C1 - Method and device for filtration of liquid - Google Patents

Abstract

FIELD: filtration of oil-containing discharges from suspended admixture and petroleum products. SUBSTANCE: filtration of liquid consists in passing drainage water through stationary filtering layer formed in porous insert of electrode due to formation of gas bubbles under action of electric current at 12 to 40 V. Device for realization of this method has two isolated electrodes connected to current source, device for inlet and outlet of liquid; electrodes are horizontal of bulk-porous type in form of two metal plate screens with bead entering each other; space between these disks is occupied by porous or fibrous material; they are isolated by means of thin perforated dielectric plate; electrode unit includes 2n bulk porous electrodes isolated from one another, where n is number of electrode pairs. EFFECT: enhanced efficiency of cleaning of industrial drainage. 3 cl, 4 dwg

Description

 The method and device relate to the field of filtering, namely the filtering of oily industrial effluents from pollution by suspended solids and oil products.

 A known method of separating particles from a fluid by filtering through a certain number of elements of the filter material in a volumetric filter. An electric field is created in the filter, which, interacting with the individual elements of the filter material, affects the movement of the medium through the filter, which contributes to the release of particles present in it [1].

 The disadvantage of this method and device is the energy intensity, since it is necessary to create sufficient voltage in the porous material itself to isolate particles in the pores of the filter. Fast filter clogging occurs. Inability to change the filtering characteristics within the required limits.

 The closest technical solution to the proposed method is a method of filtering a liquid through a bulk layer of a filter load with a particle size of 5-500 nm, in which to increase the filtering characteristics the layer of porous material is pre-saturated with smaller particles, as a result, the filtering characteristics can be changed [2].

 The disadvantage of this method is the complexity of the process, as well as the difficulty of reusing the filter layer.

 A known device for filtering a fluid selected as a prototype consists of an external cylindrical and internal perforated electrodes in contact with each other, and a charging electrode located in isolation relative to them. The surface of the inner electrode is covered by a dielectric filter. External and charging electrodes are connected to a current source [3].

The disadvantage of this device is:
the need to use for the process only a dielectric layer as a filter material;
when liquid is passed in the working chamber of the electrode under the influence of an electric field, colloidal particles are electrified, attracted and adsorbed on the surface of the filter having a high electric potential, forming a sintered layer that helps to improve the quality of filtering, however, a sufficiently high voltage must be applied to carry out the filtering process, which causes large energy costs and explosive production;
this installation is bulky, inconvenient in operation, has the same filtering characteristics.

 The objective of the invention is to increase the efficiency of cleaning industrial wastes by increasing the degree of purification, reducing energy consumption, the complexity of the process, it is possible to change filtering characteristics.

 The solution to this problem is achieved by the fact that in the method of filtering the liquid, including passing the drains through the filter layer, characterized by the degree of saturation of the pore saturation of the filter material, formed in the porous electrode liner as a result of water electrolysis under the influence of electric current on the electrode 12 - 4 V.

 The solution to this problem is also achieved by the fact that in a device for filtering a liquid containing two electrically connected electrodes connected to a current source, and devices for entering the drains and the outlet of purified water, according to the invention, two horizontally located volume-porous electrodes in the form of a structure of two plate-shaped metal grids with a collar, entering into each other, having electrical contacts, the space between the grids is occupied by a porous or fibrous material serving storage of gas bubbles resulting from electrolysis of water, with the insulation of the electrodes from each other. Moreover, the device for filtering liquid includes a filter unit containing 2n volume-porous electrodes isolated from each other by a thin insulated dielectric plate, where n is the number of volume-porous electrodes.

 Comparison of the claimed technical solutions with prototypes made it possible to establish compliance with their criterion of "novelty." In the study of other well-known technical solutions in this technical field, signs that distinguish inventions from prototypes were not identified and therefore they provide the claimed technical solutions with the criterion of "significant differences".

 Examples of the method. According to the claimed method, the filtering was carried out through a filter layer formed in a porous electrode insert. A voltage of 12–40 V was applied to the electrode. Industrial effluents for cleaning were applied from the bottom up to the volume-porous electrode; as a result, gas bubbles formed on the electrodes, which, tearing off from the electrode surface, picked up by the stream of filtered water, filled the pores of the porous liner, which is a gas storage bubbles, while reducing their size and thereby changing the filtering characteristics. The size of the produced bubbles depends on the applied voltage to the electrode. The lower the voltage applied to the electrode, the smaller the size of the bubbles filled in the pores, the better the filtering characteristics (more thorough cleaning) and vice versa, the greater the applied voltage to the electrode, the larger the gas bubbles that fill the pores, the coarser the cleaning. The interval of the operating voltage on the electrode is selected empirically. When applying a voltage to the electrode of less than 12 V, electrolysis does not occur, therefore, the entire described filtering process does not take place, and when applying a voltage to the electrode of more than 40 V, the process is not economically feasible (high energy consumption, energy-intensive process).

 With the passage of industrial waste through the specified filter layer, it is possible to achieve water purification from microscopic suspended substances and traces of oil products.

In FIG. 1 shows the dependence of the filtering ability of a volume-porous filter on voltage; in FIG. 2 - dependence of the performance of a volume-porous filter with a size of 25 cm ² voltage.

 Water for filtering was supplied from the bottom up to the filter layer for more complete use of the porous material and its uniform saturation with gas bubbles, therefore, for a uniform filtering process.

 In FIG. 3 shows the filtering unit of the device is a volume-porous filtering element (electrode); FIG. 4 - filter block composed of volume-porous filter electrodes.

 The liquid filtering device proposed in the application is a prefabricated structure consisting of a block of volume-porous filtering electrodes 1 (Fig. 1) connected to a current source using electrical contacts 3 (Fig. 4) and isolated from each other by thin perforated a dielectric plate 2 (Fig. 3). The volume-porous filter electrode (Fig. 4), a structural element of the filtering device, is made in the form of two dish-shaped metal grids: the upper 5 (Fig. 4) and lower 7 (Fig. 4) grids with a shoulder 4 and 8 (Fig. 4) , the volume between which is occupied by a volume-porous insert 6 (Fig. 4). Electrical volume-porous electrodes in the filter unit are located horizontally. Sizes L, B, H shown in FIG. 3 and 4 are determined by the required performance.

 The device operates as follows.

 Due to the prefabricated design of the filtering device containing 2n volume-porous filtering electrodes (Fig. 3), isolated from each other by a thin perforated plate 2 (Fig. 3), where n is the number of volume-porous electrodes determined by the required degree of cleaning, plant performance and features of the volume-porous electrodes themselves (Fig. 4), connected by contacts 3 (Fig. 4) to the current source, provided deep cleaning of industrial wastes.

 An example of a specific implementation. The claimed method of filtering liquid was implemented in the proposed filter device. Water for cleaning was supplied through a device for introducing industrial effluents from the bottom up into a device containing a given unit of volume-porous electrodes 1 (Fig. 3), isolated from each other by a thin perforated plate of dielectric 2 (Fig. 3). The working surface of the electrodes is horizontal. The electrodes, made in the form of two metal grids 5 and 7 (Fig. 4) with a porous insert between them 6 (Fig. 4), were connected to a current source through an electric contact 3 (Fig. 4) and applied a voltage of 12 - 40 V, in as a result, water electrolysis took place on the mesh electrode, gas bubbles formed, which were torn off from the mesh surface of the electrode, were picked up by the flow of filtered liquid coming from below and filled the pores of the porous liner 6 (Fig. 4), which served as the storage of gas bubbles, a filter layer was formed in the bulk electron de. Passing through such a filtering layer, the industrial effluent stream was purified from suspended particles and oil products.

 Using the proposed method for filtering liquids and devices for its implementation allowed to control the process and increase the efficiency of cleaning industrial waste.

Claims (2)

 1. A method of filtering a liquid, comprising passing wastewater through a filter layer, characterized in that a filter layer is used that is formed in the porous electrode liner due to the formation of gas bubbles under the influence of an electric current of 12-40 V.  2. A device for filtering liquid, including two isolated from each other electrodes connected to a current source, devices for entering the drains and the outlet of purified water, characterized in that they use two horizontally located volume-porous electrodes made in the form of two plate metal grids with a collar that enters into each other, the volume between which is occupied by a porous or fibrous material, isolated from each other by a thin perforated dielectric plate, constituting a block containing 2n Volumetric-porous electrodes where n - the number of isolated electrode pairs.

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