RU2470875C1 - Plant for electroblasting activation of water pulps and suspensions - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention may be used in construction, aluminium industry, treatment of effluents. Water pulps and suspensions are subjected to electroblasting activation. Proposed plant comprises control board, HV transformer, and pulse generators with capacitors battery. Pulse generators is connected via HV cables with activation reactor. The latter is made of sheet steel and shaped to rectangular box with pump and suspension feed and discharge branch pipes. Covers with electrode cells are secured to flanges on reactor two opposite walls. U-shape chamber made from sheet steel is arranged inside aforesaid box. Pulp is fed from bottom to top between reactor covers and U-shape chamber walls. Homogenised pump escapes from reactor via branch pipe arranged at U-shape chamber bottom.

EFFECT: simple, high-efficiency plant.

2 cl, 3 dwg, 1 tbl, 2 ex

Description

The invention relates to electric explosive disintegration and activation of aqueous suspensions, emulsions, colloidal solutions, as well as to the purification of water from pollutants of natural and man-made origin. The invention can be used to increase efficiency in the following processes:

- increase the chemical activity of milk of lime used in construction and drinking water supply, wastewater treatment in public utilities;

- purification of aluminate solutions from silicon in the aluminum industry;

- increase the speed and yield of chemical reactions in pulps and aqueous suspensions;

- disinfection and treatment of drinking and wastewater.

A known method of processing lime milk with high voltage electric discharges and a device for processing mineral raw materials [Shepelev II, Medvedev GP, Dashkevich R.Ya. Intensification of hydrometallurgical processes of processing aluminum-containing mineral raw materials using electric explosive effects // Electric discharge in liquids and its use in industry: Abstract. Doc. VI International Conference., Nikolaev, 1992. - S. 171, A.S. 1570769 USSR, IPC V02C 19/18. Publ. 06/15/1990], as a result of which the chemical activity of milk of lime increases and milk consumption for technological needs is reduced by 2-3 times. To activate milk of lime, the discharge energy was 7-14 kJ, and the discharge gap was 3-5 mm. For conductive media, for example, an aqueous suspension of Ca (OH) ₂  - milk of lime, the magnitude of the interelectrode gap and the bore of the apparatus due to energy losses are sharply reduced while increasing energy and voltage in the discharge. With such a high energy consumption, the method of electro-hydraulic activation of milk of lime is not economical, and it is impossible to pump large volumes of technological solutions through a reactor with a small cross section, the erosion rate of the electrodes is high, the adjustment or replacement of which requires the reactor-activator to stop working. Also known are devices for electro-hydraulic (voltage up to 110 kV) and electro-pulse (discharge voltage more than 110 kV) processing of solid materials [Equipment and technological processes using the electro-hydraulic effect / Ed. G.A. Gulogo. - M., Mechanical Engineering, 1997. - 320 p .; Discharge-pulse technology for processing mineral media / G. Gavrilov et al. - Kiev: Science. Dumka, 1979. - 164 p., RF Patent 2099142 ⁶  B02C 19/18]. Known installation for disinfection and water purification patent US 5464513 "Method and apparatus for water decontamination using electrical discharge", IPC B01J 19/08, publ. 07/11/1995, which contains a pulse generator, including a pulse transformer, providing an output voltage of 10 to 50 kV, connected to the electrodes.

The disadvantage of these devices is high power consumption and low productivity, the inability to adjust the distance between the high voltage and grounded electrodes, which necessitates the constant maintenance of the required value of this distance, which is carried out by periodically replacing worn electrodes.

The prototype of the invention is the installation according to the patent of the Russian Federation 2019906, IPC Н03К 3/53, publ. 09/15/1994, for crushing ores and rocks, in the construction industry, for waste treatment and in other areas in which electric pulse technology is used. Installation of a GIN high-voltage pulse source, a pulsed current generator (GIT) and a high-voltage electrode immersed in a grounded container with technical fluid as a source of high-voltage pulses, a high-frequency transformer consisting of a set of inductors was used, and a high-voltage cable was used as a high-voltage electrode. The destruction is carried out as a result of the energy input from the pulse current generator connected to the central conductor of the high-voltage cable and consisting of a high-voltage high-current thyristor and a capacitor battery, the high-voltage cable acting as an electrode and immersed in a grounded container, in which various materials are destroyed by electric pulses.

The disadvantages of the described installation include high energy consumption, low productivity due to the design difficulties of the installation with high-voltage cables acting as an electrode, the inability to adjust the distance between the high-voltage and grounded electrodes, through which a suspension or pulp must be pumped with a sufficiently high mass velocity, and a high rate of erosion of the electrode during a discharge whose energy is determined by the equation E = CU ² / 2, where C is the capacitance of the capacitor, and U is the voltage. The discharge energy increases in proportion to the square U and even at C = 0.2 μF and U = 110 kV, E = 1.21 kJ, and the higher the energy, the higher the erosion of the electrode, which increases the interelectrode distance, voltage and discharge current.

The objective of the invention is to improve the quality of the prepared raw materials, disinfection and purification of water, increase the productivity of the installation of electric explosive activation of water pulps and suspensions by reducing the specific energy consumption by increasing the volume of processed water pulps and suspensions, reducing operating costs for its maintenance.

The technical result of the present invention is the creation of an inexpensive and easy to maintain, high-performance installation of continuous operation, the basis of which is the design of the reactor-activator, which allows the maximum use of the energy of high-voltage pulse discharges (VIR) for processing suspensions, pulps and solutions passing through the reactor with the output from it a more homogenized suspension, which provides energy-saving energy consumption for activation and disintegration of water for consumers solutions and suspensions, which is ensured by the use of capacitors with a capacity of 0.1-0.25 μF, with voltage regulation up to 50 kV at a frequency of 0.5-10 Hz. The discharge energy from capacitors in the proposed installation is 45 - 125 J / dm ³ , against 3-14 kJ in analogues. At the same time, as established by the experimental and pilot studies shown in the table, this energy is sufficient for crushing mineral particles along spikes and interfaces, increasing the rate of chemical reactions in aqueous media by increasing the specific surface of solid particles and secondary effects of electric discharge - ultraviolet radiation, cavitation and ozone formation, increasing the surface energy of particles by removing passive films, destroying ultraviolet microorganisms th radiation, shock waves, by H, OH, O et al., appearing in the gas-vapor discharge gap cavity and solutions of other similar tasks. In addition, with a relatively low discharge energy, the electrode undergoes erosion to a lesser extent, which is important when creating high-performance reactors. The required capacitance of the capacitors and the discharge voltage, depending on the problem to be solved, are determined on a special laboratory bench, which determines the necessary energy consumption for a particular type of raw material, the cross section of the reactor-activator, the required number of electrode cells and the frequency of the discharges. At the same time, the tasks of minimizing the operational time costs associated with adjusting the discharge gap between the high-voltage and grounded electrodes and the procedure for quickly setting up the installation for a given capacity for a specific type of raw material are solved. The design of the proposed reactor-activator provides a slurry and suspension capacity of up to 90 m ³ / hour and more, which is required in hydrometallurgy, enterprises of the construction industry, utilities, and is characterized by small dimensions with high productivity.

Figure 1 and figure 2 schematically shows the installation for the electric explosive activation of aqueous pulps and suspensions and the design of the electrode cell, where:

1 - control panel; 2 - step-up high-voltage transformer 220-380 V, with voltage regulation up to 50 kV: 3 - pulse generator: 4 - grounding; 5 - covers of the reactor-activator; 6 - a rectangular box of the reactor-activator: 7 - electrode cells on which electrodes are fixed in insulators; 8 - pipe supply pulp solution; 9 - pipe outlet processed pulp, solution; 10 - cavitation U-shaped cavity of the reactor-activator; 11 - flanges for mounting the covers of the reactor-activator; 12 - activator reactor; 13 - high-voltage cables: 14 - racks; 15 - hairpins; 16 - flange mounting the electrode cell; 17 - insulator from plexiglass or caprolon; 18 - rubber damper; 19 - electrode; 20 - nuts; 21 - washer; 22 - rubber gasket; 23 - central damper insert.

Installation works as follows:

In the electrode cell 7, pressed against the housing of the activator reactor by a flange 16, with a rubber damper 18, an electrode 19 and a central damper insert 23 for adjusting the discharge gap, without disconnecting the cells from the activator reactor 12, the discharge gap necessary for breakdown is set. To do this, in the cell 7 fixed in the center of the plexiglass or caprolon insulator 17, the damper package consisting of an electrode 19, a rubber damper 18 pressed against the insulator by a washer 21 and a nut 22 through the central damper insert with an internal thread 23, the discharge gap is adjusted by screwing the electrode 19 until it stops against the wall of the U-shaped cavity 10, and by unscrewing the electrode and securing it in the installed position with lock nuts on the free end of the electrode 19 (not shown). Then, at the end of the electrode 19, a high-voltage cable 13 (not shown) is rigidly fixed with nuts. The electrode 19, together with the central insert of the damper 23 and the cable 13 fixed at the end, can move back and forth under the action of shock waves, which are damped by the rubber damper 18. The interelectrode distance does not change. An increase in the interelectrode distance is possible due to erosion of the working surface of the electrode tip and, in accordance with the installation experience at the alumina refinery, is no more than 0.5 mm in 500 hours of operation at an average discharge frequency of 2 Hz in an alkaline solution of milk of lime. With an increase in the interelectrode distance of 0.4-0.5 mm, the breakdown voltage increases by 1-1.5 kV, which fixes the BUN (voltage control unit) and the control panel 1 increases the discharge voltage, instead of adjusting the interelectrode distance up to its increase by 0 5 mm. When the interelectrode distance is increased by more than 0.5 mm, the unit’s power supply is automatically turned off. The time for manual adjustment of 1 electrode 19 does not exceed 5 minutes, and the time for replacing a fully assembled cell 7 with adjustment of the discharge gap is no more than 15 minutes.

After setting the necessary discharge gap between the electrode 19 and the wall of the U-shaped cavity 10 with the valve of the outlet 9 of the solution or suspension exiting from the activator reactor 12, designed for the processing of aqueous solutions and suspensions with a particle size of less than 1-2 mm and made in the form of a rectangular box 6 with a conical lower part and flanges 11 for mounting the covers of the reactor-activator 5 with electrode cells 7, the valve of the inlet pipe 8 opens (valves not shown). A pulp or an aqueous solution is supplied to the activator reactor 12 through the inlet pipe 8 with its outlet through the pipe 9. This order of opening the valves avoids water hammer and makes the reactor-activator housing 12 made of sheet steel, even 3-4 mm thick. The suspension passes from bottom to top between the covers of the reactor-activator 5 with the electrode cells mounted on them with high-voltage electrodes 7 and the internal U-shaped cavity 10, which is the second grounded electrode made of sheet steel fixed to the racks 14 of the box 6 of the reactor-activator 12 (Fig. .1, section AA). Then it is poured through the upper edges into the U-cavity 10, vibrating under the influence of shock waves, filling the reactor-activator 12. Turn on the control panel 1 with the necessary frequency VIR, the electrical energy stored in the capacitor bank of the pulse generator 3, high-voltage cables 13 connecting a pulse generator 3 with each electrode cell 7, is transmitted to the reactor-activator 12 for processing an aqueous solution or pulp.

Thus, after processing a more homogenized suspension with the initial ratio of solid to liquid phases (T: G), before leaving the activator reactor 12 through the pipe 9, the suspension is additionally in the cavitation zone, being subjected to direct and indirect VIR exposure over the entire volume of the activator reactor 12 and inside the U-shaped cavity 10.

The optimal size ratio between the cover of the reactor-activator and the wall of the U-shaped cavity, the width of the cavity and between the second wall of the cavity and the second cover of the reactor-activator is x: 2x: x, as shown in figure 1, and if x = 100 mm, then the width of the U-shaped cavity is 2 times greater, i.e. 200 mm, which ensures equal speed of suspension or solution throughout the volume of the reactor-activator. The ratio of the distance between the cover of the reactor-activator and the side walls of the U-shaped cavity is half of the internal size of the U-shaped cavity.

Examples of the installation.

1. Processing of milk of lime. Preliminary studies in a stationary laboratory reactor studied the dependence of the degree of grinding of particles of the solid phase in the milk of lime on the amount of VIR. A laboratory experiment is used to determine the energy consumption necessary to obtain the maximum effect from VIR - processing this type of raw material, after which the design parameters of the reactor-activator, the number of electrodes and the operating discharge frequency for a given reactor-activator performance for a specific type of raw material are determined. After treatment with 3, 5, 7, 10, 13, 17, and 20th digits, samples of lime milk were passed through a sieve with a mesh of 50 μm, the sieve was washed with water, dried, and the mass of particles with a size of more than 50 μm was determined. Based on these results, they judged the effectiveness of the VIR processing of milk of lime and designed an industrial unit for production testing. A pilot plant crashed into an existing product pipeline. The working section of the industrial reactor-activator was 0.08 m ² . The flow rate of milk of lime through the working section of the reactor-activator was at a flow rate of 44 m ³ / h - 0.1527 m / s, and at a flow rate of 90 m ³ / h - 0.3125 m / s. The distance between the axes of the electrodes was 200 mm, and between the axis and the wall of the casing - 100 mm. On one cover, 6 electrode cells were installed. The test results of the reactor-activator in the current production are shown in figure 3, the dependence of the silicon module M _cr  from the frequency of discharges. Mkr - silicon module was determined in the laboratory of the plant. This is a dimensionless quantity representing the mass ratio Al ₂ ABOUT ₃ / SiO ₂  in aluminate solutions after removal of SiO from them ₂  milk of lime. Since identical volumes of initial reagents are used to determine the microcrystal density, this value can be taken as a characteristic of the chemical activity of milk of lime subjected to VIR treatment due to an increase in the specific surface area of Ca (OH) particles ₂  and removing from the surface of these particles passive films, while extracting silica from aluminate solutions. The second characteristic of activity can be the amount of solid particles with a size of more than 50 microns before and after the VIR treatment. In a production experiment, a 5 kW power source was used. Specific energy consumption during activation of milk of lime at a rate of 90 m ³ / h amounted to 0.055 kWh / m ³ .

2. Water disinfection using VIR treatment.

The effectiveness of using VIR for disinfecting water was performed on a laboratory reactor with one electrode as follows:

For research, the daily culture of the test strain of Escherichia coli GKPM 240418 M-17 was used. A suspension of bacteria was prepared according to a standard sample of turbidity GISK them. Tarasovich (OSO-42-28-85 P), which corresponded to a concentration of 0.93 · 10 ⁹  cells / ml for germs of the intestinal group at a temperature of 10-30 ° C, it was poured into a reactor pre-washed with distilled water and poured into a reactor of 0.5 or 1 dm ³  water. In the experiment, 3 types of cylindrical reactors with a diameter of 10, 15 and 20 cm were used, into which the test solution with a volume of 0.4, 1.85 and 1.6 dm was poured ³  accordingly, with blocked water supply and outlet pipes and a pipe for supplying air to the reactor. The electrode pair was placed in the center of the activator reactor; the distance from the center of the discharge to the wall of the activator reactor was 50, 75, and 100 mm, respectively. The installation was turned on at a frequency of 0.5 Hz. Samples with a volume of 5-6 ml were taken through every 3 discharges through a water inlet with microventil, three samples of 1 ml were taken from them and analyzed in accordance with the order of the Sanitary and Epidemiological Supervision М3 No. 720 and МУ-287-113. The research results showed that in a reactor with a diameter of 100 mm, after 6 discharges, microorganisms are completely destroyed. In a reactor with a diameter of 150 mm, microorganisms are destroyed after 7-8 discharges, and in a reactor with a diameter of 200 mm, after 12-14 discharges. Obviously, with an increase in the distance from the center of the discharge to the wall of the reactor-activator by a factor of 2, the power of UV radiation decreases by a factor of 2. For an industrial installation, based on these data, it is advisable to use a type 2 reactor with a cross section in the form of a slit 100 mm high. The width of the slit, with the electrodes located along this width, is selected based on the required performance so that the distance between the centers of the electrodes is 100-150 mm, between the wall and the extreme electrode - 50-75 mm. Energy consumption for VIR-disinfection of water at a design capacity of 100 m ³ / h using the design of the reactor-activator of the second type, tested during the activation of milk of lime under industrial conditions with a slit width of 50 mm, will not exceed 0.04 kWh / m ³  water.

The results of the processing of milk of lime obtained during operation of an electric blasting plant

No. p / p frequency Hz Flow, m ³ / h Particle Content +0.63, wt.% one 0 * 56 35.1 2 one 56 - 3 2 60 - four 2.7 61 - 5 0 * 90 25.1 6 1.8 90 0.36 7 2.7 90 0.2 0 * - initial milk of lime, without processing

Claims (2)

1. Installation for electric explosive activation of water pulps and suspensions with low energy consumption, consisting of a control panel, a high voltage transformer, a pulse generator with a capacitor bank, characterized in that the pulse generator with a discharge energy from the capacitor 45-125 J / dm ³ and an operating frequency of 0 , 5-10 Hz is connected by high-voltage cables to the reactor-activator, which is made of sheet steel in the form of a rectangular box with pulp and slurry I / O pipes to ensure high productivity of the installation lid, on two opposite walls of which lids are fastened to the flanges with rubber dampers mounted externally on them, fast-detachable electrode cells mounted on studs, a U-shaped sheet steel cavity vibrating under the influence of shock waves is installed inside the box to use secondary cavitation effects inside the cavity during the processing by discharges of pulps, solutions and thin suspensions, the supply of which is carried out from the bottom up between the covers of the reactor-activator with electrode cells and walls U-image cavity, the homogenized solution, pulp or suspension leaves the activator reactor through a pipe located in the bottom of the U-shaped cavity, and the gap width between the covers and the wall of the U-shaped cavity is half the width of the inner cavity to ensure equal flow rate of the liquid phase along the entire volume of the reactor-activator. 2. Installation according to claim 1, characterized in that the electrodes are assembled in insulators in such a way that after removing the voltage, it is possible to adjust the discharge gap outside the activator reactor in no more than 5 minutes by screwing the electrode through the damper insert all the way into the grounded electrode and unscrewing back until the required discharge gap is reached, and the shock waves are quenched on rubber dampers.

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