Electrolysis is a chemical-physical phenomenon in the decomposition of substances into components by means of an electric current, which is widely used for industrial purposes. Based on this reaction, aggregates are made for the production of, for example, chlorine or non-ferrous metals.
The constant rise in prices for energy resources has made domestic electrolysis plants popular. What are such designs, and how to make them at home?
General information about the electrolyzer
An electrolysis plant is a device for electrolysis that requires an external energy source, structurally consisting of several electrodes that are placed in a container filled with electrolyte. Also, such an installation can be called a device for splitting water.
In such units, the main technical parameter is productivity, which means the volume of hydrogen produced per hour and is measured in m³/h. Stationary units carry this parameter in the name of the model, for example, the SEU-40 membrane unit produces 40 cubic meters per hour. m of hydrogen.
Other characteristics of such devices are completely dependent on the intended purpose and type of installations. For example, when performing electrolysis of water, the efficiency of the unit depends on the following parameters:
- The level of the smallest electrode potential (voltage). For normal operation of the unit, this characteristic should be in the range of 1.8-2 V per plate. If the power supply has a voltage of 14 V, then it makes sense to divide the capacity of the electrolytic cell with an electrolyte solution into 7 cells by sheets. Such an installation is called a dry cell. A smaller value will not start electrolysis, and a larger one will greatly increase energy consumption;
- The smaller the distance between the plate components, the less resistance there will be, which, when a large current passes, will lead to an increase in the production of a gas substance;
- The surface area of the inserts has a direct impact on performance;
- Thermal balance and degree of electrolyte concentration;
- Material of electrode elements. Gold is an expensive but ideal material for use in electrolyzers. Due to its high cost, stainless steel is often used.
Important! In constructions of a different type, values will have different parameters.
Water electrolysis plants can also be used for purposes such as disinfection, purification and water quality assessment.
The principle of operation and types of electrolyzer
The simplest device has electrolyzers that split water into oxygen and hydrogen. They consist of a container with an electrolyte in which electrodes connected to an energy source are placed.
The principle of operation of the electrolysis plant is that the electric current that passes through the electrolyte has a voltage sufficient to decompose water into molecules. The result of the process is that the anode releases one part of oxygen, and the cathode produces two parts of hydrogen.
Types of electrolyzers
Devices for splitting water are of the following types:
- dry;
- Flow-through;
- Membrane;
- Diaphragm;
- Alkaline.
dry type
Such electrolyzers have the simplest design (picture above). They have a peculiarity, which lies in the fact that manipulation with the number of cells makes it possible to power the unit from a source with any voltage.
flow type
These installations have in their design a bath completely filled with electrolyte with electrode elements and a tank.
The principle of operation of the flow electrolysis plant is as follows (in the picture above):
- during electrolysis, the electrolyte together with the gas is squeezed out through the pipe "B" into the tank "D";
- in the tank "D" the process of separating the gas from the electrolyte takes place;
- gas exits through valve "C";
- the electrolyte solution returns through tube "E" to bath "A".
Interesting to know. This principle of operation is configured in some welding machines - the combustion of the emitted gas allows you to weld the elements.
Membrane type
The membrane-type electrolysis plant has a similar design to other electrolyzers, however, the electrolyte is a polymer-based solid substance, which is called a membrane.
The membrane in such aggregates has a dual purpose - the transfer of ions and protons, the separation of electrodes and electrolysis products.
diaphragm type
When one substance cannot penetrate and affect another, a porous diaphragm is used, which can be made of glass, polymer fibers, ceramics or asbestos material.
Alkaline type
Electrolysis cannot take place in distilled water. In such cases, it is necessary to use catalysts, which are alkaline solutions of high concentration. Accordingly, the main part of the electrolysis devices can be called alkaline.
Important! It should be noted that the use of salt as a catalyst is harmful, since chlorine gas is released during the reaction. The ideal catalyst can be sodium hydroxide, which does not corrode iron electrodes and does not contribute to the release of harmful substances.
Self-manufacturing of the electrolyzer
Anyone can make an electrolyzer with their own hands. For the assembly process of the simplest design, the following materials will be required:
- stainless steel sheet (ideal options are foreign AISI 316L or domestic 03X16H15M3);
- bolts M6x150;
- washers and nuts;
- transparent tube - you can use the water level, which is used for construction purposes;
- several herringbone fittings with an outer diameter of 8 mm;
- a plastic container with a volume of 1.5 l;
- a small filter for running water, such as a filter for washing machines;
- check water valve.
Assembly process
Assemble the electrolyzer with your own hands according to the following instructions:
- The first step is to mark up and further cut the stainless steel sheet into equal squares. Sawing can be carried out with an angle grinder (grinder). One of the corners in such squares must be cut at an angle for the correct fastening of the plates;
- Next, you need to drill a hole for the bolt on the opposite side of the plate from the corner cut;
- The connection of the plates must be done alternately: one plate on the "+", the next on the "-" and so on;
- Between differently charged plates there should be an insulator, which acts as a tube from the water level. It must be cut into rings, which should be cut lengthwise to obtain strips 1 mm thick. Such a distance between the plates is sufficient for efficient gas release during electrolysis;
- The plates are fastened together by means of washers as follows: a washer is mounted on the bolt, then a plate, then three washers, then a plate, and so on. Plates that are positively charged are mirrored to negatively charged sheets. This allows you to prevent touching the electrodes with sawn edges;
- When assembling the plates, you should immediately insulate them and tighten the nuts;
- Also, each plate must be ringed in order to make sure that there is no short circuit;
- Next, the entire assembly must be placed in a plastic box;
- After that, it is necessary to mark the places where the bolts touch the walls of the container, where to drill two holes. If the bolts do not fit into the container, then they must be cut with a hacksaw;
- Next, the bolts are tightened with nuts and washers for tightness of the structure;
- After the done manipulations, you will need to make holes in the container lid and insert fittings into them. Tightness in this case can be ensured by lubricating the joints with silicone-based sealants;
- The safety valve and filter in the design are located at the gas outlet and serve as a means of controlling its excessive accumulation, which can lead to disastrous consequences;
- The electrolysis plant is assembled.
The final stage is testing, which is carried out in this way:
- filling the tank with water to the level of the fixing bolts;
- connecting power to the device;
- connection to the fitting of a tube, the opposite end of which is lowered into the water.
If a weak current is applied to the plant, then the release of gas through the tube will be almost imperceptible, but it can be observed inside the electrolyzer. By increasing the electric current, adding an alkaline catalyst to water, one can significantly increase the yield of a gaseous substance.
The manufactured electrolyzer can be an integral part of many devices, for example, a hydrogen burner.
Knowing the types, main characteristics, design and principle of operation of electrolysis plants, it is possible to correctly assemble a home-made structure, which will be an indispensable assistant in various everyday situations: from welding and saving fuel consumption of vehicles to the operation of heating systems.
Video
The essence of the electrolysis process (Fig.) is that when an electric direct current flows through the electrolytic bath, one of the following phenomena can occur:
Or there is a deposition of particles of a substance from the electrolyte on the electrodes of the bath (electroextraction)
Or there is a transfer of a substance from one electrode to another through an electrolyte (electrolytic refining)
BOOKMARK
As an electrolyte, solutions of salts, acids and bases, usually in water, are used.
Ionic conduction takes place in the electrolyte. When voltage is applied to the electrodes, the ions move to the electrodes, neutralize and settle on them. In this case, either electroextraction or electrolytic refining takes place.
The notion of a normal potential is of primary importance in the choice.
If the electrode is made of the same metal as the electrolyte, then at a certain potential there is neither the first nor the second process between the electrode and the electrolyte. Such a potential is called normal.
If a more negative potential is applied to the electrodes, then electroextraction begins.
If more positive, then electrolytic refining.
Electrolysis is used to obtain or purify metals.
Quantitatively, the electrolysis process is described by the same Faraday law.
U email \u003d E p + E p + U e + U s
E p - decomposition voltage
E p - the sum of the anode and cathode PN
U e - voltage drop on the electrolyte
U s - voltage drop on the electrode contacts buses
U e \u003d I ∙ R ext
U e \u003d I ∙ (R w + R to + R e)
P el \u003d I ∙ (E p + E p + U e + U s)
τ – technological process time
E p - useful work
The efficiency of the electrolysis process is described by the mass of the substance.
The raw material for obtaining Zn is zinc blende ZnS. This mineral is first subjected to oxidation, roasting, and then subjected to leaching.
ZnSO 4 +H 2 O(5÷6%) The conductivity of such a solution is low, therefore, 10÷12% H 2 SO 4 is added to this solution
The electrolytic bath is made of wood or concrete and is insulated from the ground.
The electrolysis process is carried out at t= 35÷40 0 C
j= 400÷600 A/m 2
PN appears on the cathode - 1.1 V (normal potential -0.76 V)
Electroextraction occurs - deposition of Zn on the cathode.
1/g e = 3500 kWh/t
τ = 40÷50 hours
After that, Zn is stripped from the cathode and remelted.
ReceiptAl
The electrolyte is not a solution, but a melt. Alumina Al 2 O 3 is used as raw material
t pl \u003d 2050 0 С
The melt of this material has low conductivity. Therefore, alumina and cryolite Na 3 AlF 6 are used as electrolyte
t pl \u003d 950 0 С
Bathtubs and electrodes are made of carbon or graphite.
I= 200÷250 kA
j= 7÷10 kA/m 2
1/g e = 14000÷16000 kW∙h/t
Electroplating
This is an electrotechnological process of metal deposition on the surface of both metal and non-metal products using electrolysis.
The coating thickness does not exceed tens of microns.
There are 2 varieties:
electroplating
electrotype
Electroplating - copper plating, gilding, gilding, chromium plating, nickel plating ...
Before processing, the surface is thoroughly cleaned, then acid etching is carried out with H 2 SO 4 , HCl. The salt solution of the deposited metal is used as the electrolyte. Sometimes acids and bases are added to increase conductivity. The anode is made of deposited metal, the product is the cathode.
There is a transfer of metal from the anode to the cathode, processing occurs at low current densities, not more than tens of A/m 2 .
Galvanoplasty - obtaining exact copies from products.
Electrodynamic effect and electric wind
Under the action of an EF on gas and liquid media, their movement is observed. It is due to the transfer of kinetic energy during the collision of ions of the medium with neutral molecules.
This phenomenon is called the electric wind for gaseous media.
The electric wind is always directed away from the electrode with a smaller radius of curvature.
The strength of the impact on the electric discharge is estimated simply:
F=E∙ρρ– charge density
Some regularities of the electric wind have been established:
Impulse installations
1. Installations of electroerosive processing.
2. Installations of electro-hydraulic processing.
3. Electric pulse welding installations.
4. Installations for magnetic pulse metal processing.
5. Installations of pulsed electrochemical processing.
1. Installation for electroerosive processing.
The operation of these devices is based on the phenomenon of electroerosion, that is, the destruction of the material being processed (Me) under the action of current pulses flowing between the electrode of the surface to be treated, usually in a dielectric medium.
When current pulses flow in the spark channel, electricity is converted into heat in the spark channel between the electrodes and the surface. There is heating, and its removal.
Main processing parameters:
Pulse repetition rate from hundreds to hundreds of thousands of Hz,
Current amplitude from fractions to thousands of A,
The duration of impulses is from fractions to several thousand seconds.
By changing these parameters, the required processing mode is set. Scheme 1.
1-vertical machine stand
2-working bath
3-table for the installation of the working bath, which ensures the movement of the working bath in two coordinates in the horizontal plane.
4-reversible electrode-product, located inside the working bath and moving with it.
5-device for vertical movement.
6-source of high impulse voltage (periodic, not lower than 1kV).
7-system for supplying the working dielectric liquid (usually transformer oil). The system includes pumps, filters, liquid return systems, coolers.
8-electrode-tool, made of a more refractory material than the electrode-product (tungsten, graphite).
Installation operation
The electrode-tool (8) is brought to the surface of the product (4) and the voltage source (6) is turned on.
Those. high-voltage pulses are applied to the gap between the electrode-tool (8), the product (4), and electric spark discharges occur in this gap. These channels are very concentrated converters of electrical energy into thermal energy with a bulk density of 10^12 J/m3.
In this case, the power density is 1-10^7 W/cm2. The released thermal energy leads to heating, melting, evaporation of the metal of the product and its removal with the help of a working fluid. In this case, multiple electrical discharges pass layer by layer throughout the entire surface to be treated. As a result, recesses are formed in the product, which copy the shape of the electrode.
Switching power supplies based on capacitive energy storage devices are used as power sources.
Scheme 2.
Power comes from a 220V network using a current transformer. The increased voltage is rectified using the VD rectifier, the rectified voltage is used to periodically load the capacitor bank Cb. After charging this capacitance, a discharge circuit is formed containing the inductance Lp and the working spark gap. The capacitance is discharged, a current Lp flows in the discharge circuit. After that, the thyristor VD is closed and the process of charging the capacitance Sat is repeated. The processing mode (roughness, productivity) is controlled by changing the power and frequency of the current pulses ip.
Such plants have high productivity and high quality processing. For some types of processing, such installations are indispensable.
Disadvantage: there is wear of the tool electrode.
Electro-hydraulic treatment plants
Such installations are based on the use of an electro-hydraulic effect.
The electrohydraulic effect consists in converting the electricity stored in a capacitive storage into mechanical energy of a shock wave using a powerful spark discharge, which is created in a liquid medium (usually water).
The electrical circuit is almost the same as in the previous case. The difference is in the length of the discharge gap (it is longer).
Technological process parameters:
1)
- steepness of the rising current;
2)
up to 250 kA;
3)
up to 100 MW;
4)
before 
J.
With such parameters, the spark channel has the character of an explosion.
Channel temperature 
TO; Pressure 
MPa.
The pressure is transferred to the fluid.
Areas of use:
a) knockout of molding cores in castings of complex shape;
b) cleaning of castings and various surfaces from scale;
c) crushing, grinding of various materials;
d) recycling of reinforced concrete products.
Pulse welding plants
Designed to obtain permanent welded metal joints by compressing the joint and heating it to the melting temperature by passing a pulsed current.
The scheme of the process is the same as in the previous case. The difference is only in the load. Parts practically do not heat up.
The advantage is the localization of thermal effects, the destruction of small welded parts is excluded.
Magnetic pulse processing devices
These installations are based on the conversion of EE into the energy of a pulsed MF, then there is an interaction of the pulsed fields created by the tool - the inductor, with the El induced by it. current in the workpiece.
As a result, the MF energy is converted into mechanical energy, which deforms the workpiece in the necessary way.
ZU - charger;
- a battery of inductances (creates a pulse of the desired shape);
IN - tool inductor;
Z - blank.
Multi-circuit and single-circuit installations
Multi-circuit installation contains one or more instruments - inductors, made in the form of solenoids.
MP of the solenoid created by the current 
induces current in the workpiece 
. The currents interact and provide mechanical forces and deformation of the workpiece.
- intrinsic inductance of AI;
- AI active resistance;
- active resistance 
;
- coefficient of mutual induction;
- inductance and active resistance of the workpiece.
In the scheme of PP, it is determined by the TOE method. The operation technology according to this scheme is used in 3 versions:
2) distribution (induction inside the workpiece);
3) sheet forming (a flat billet is deformed).
Single circuit diagram:
In this case, the discharge current flows directly through the workpiece. The workpiece is part of the AI.
branches into 
and 
. The interaction of currents leads to deformation of the workpiece, and it acquires the shape shown by the dotted line.
Advantages:
Disadvantages:
The material must have high electrical conductivity;
The need to install conductive gaskets when forming materials that do not conduct electricity well. current;
Difficulties in processing surfaces that have a gap for el. current;
Difficulties with processing massive workpieces.
Installations of pulsed electrochemical processing. These are the electrochemical technological processes discussed above, in which pulse voltage is used instead of constant voltage.
Currently, in Russia, an increasing number of water supply and sanitation facilities, as well as industries, refuse to use commercial liquid chlorine and hypochlorites, making a choice in favor of organizing their own synthesis of the necessary reagents directly at the objects of use.
The production requires sodium chloride (salt), water, electricity.
Reasons for this refusal:
1. Liquid chlorine is very dangerous.
Despite the low cost of chlorine, the measures and costs associated with its use greatly complicate and increase the cost of the entire production process.
2. Commercial sodium hypochlorite (GPCHN 19%) is very expensive.
The cost of 1 ton of GPKhN brand A does not exceed 20-30 thousand rubles. However, the amount of sodium hypochlorite equivalent to 1 ton of chlorine is already 100-150 thousand rubles. (since hypochlorite contains only 15-19% active chlorine and tends to further decompose).
Advantages of electrolysis equipment:
- waiver of security costs during transportation and storage;
- during the operation of electrolysis equipment, accidents associated with the leakage of a large amount of reagent are impossible. The objects of operation of electrolysis plants for the synthesis of chlorine reagents do not belong to HIFs and are not included in the corresponding register;
- independence from the supplier - the reagent is produced in the required quantity, the performance is regulated, which increases the energy efficiency of the facility;
- cheap raw materials - the cheapest technical salt can be used for synthesis. This will require the installation of additional equipment for cleaning the salt solution entering the electrolyzers, however, these costs pay off in less than 1 year due to significant savings in raw materials;
- the resulting reagent is cheaper than the commercial one;
- for water supply facilities that use UV installations as the main method of disinfection - when introducing UV equipment, it is impossible to completely abandon the use of chlorine reagents, since it is necessary to ensure the sanitary condition of structures and networks, as well as the safety of transporting water to the consumer. Electrolysis plants, together with UV equipment, fully satisfy the need for chlorine, while the facility is excluded from the HPF register.
Electrolysis plants produce different reagents:
- chlorine or chlorine water (Aquachlor, Aquachlor-Beckhoff, Aquachlor-Membrane/Diaphragm);
- combined disinfectant with increased efficiency - an oxidant solution containing chlorine, chlorine dioxide, ozone (Aquachlor, Aquachlor-Beckhoff);
- low-concentration HPCHN 0.8% (LET-EPM, Aquachlor, Aquachlor-Beckhoff);
- highly concentrated HPCHN 15-19% (Aquachlor-Membrane/Diaphragm).
All of these reagents are suitable for the purposes of water disinfection. The only limitation is the pH of the water to be disinfected at the point of reagent entry - for water with a pH above 7.5, it is recommended to use chlorine water instead of hypochlorite, which is ineffective in an alkaline environment.
Let us dwell in more detail on each type of equipment of LET LLC:
Aquachlor and Aquachlor-Beckhoff:
- the resulting reagent has increased efficiency;
- individual modules have little performance. This allows for flexibility in responding to
- the need for a reagent. The optimal performance of the complex is up to 250-500 kg of active chlorine per day;
- frequency of replacement of reactors - 1 time in 3-5 years;
- ease of maintenance.
LET-EPM:
- unlimited productivity of complexes;
- ease of operation and low requirements for the quality of raw materials;
- the frequency of replacement (overcoating) of the electrode block - once a year;
- reagent is suitable for most objects.
Aquachlor-Diaphragm:
- the possibility of obtaining chlorine water and concentrated HPCHN 19%, as well as the simultaneous production of these reagents;
- the frequency of replacement of the electrode coating and diaphragm - no more than 1 time in 10 years;
- high requirements for the quality of the salt solution;
- the possibility of flushing the diaphragm and returning to work in case of contamination with saline of inadequate quality;
Aquachlor Membrane:
- unlimited productivity of the complex (but not less than 50-100 kg/day);
- the possibility of obtaining chlorine and concentrated HPCHN 19% of high purity, suitable for synthesis;
- the frequency of replacement of the electrode coating and membrane - no more than 1 time in 10 years;
- very high requirements for the quality of the salt solution;
- in case of contamination of the membrane, it must be replaced with a new one;
- maintenance of equipment requires qualified personnel.
The cost of the final product (in ascending order, from lower to higher):
- Aquachlor-Diaphragm
- Aquahdlor Membrane
- Aquachlor/Aquachlor-Beckhoff
- LET-EPM
Using the principle of obtaining hydrogen by electrolysis of an aqueous solution of alkali, I decided to make a simple and compact apparatus, convenient for working with small parts, when soldering with hard solders. Due to the small external dimensions of the electrolyser, it will find a place even on a small desktop, and the use of a standard rectifier for recharging batteries as an electrolytic unit facilitates the manufacture of the unit and makes it safe to work with.
The relatively small, but quite sufficient performance of the apparatus made it possible to extremely simplify the design of the water seal and guarantee fire and explosion safety.
Electrolyzer device
Between the two boards, connected by four pins, there is a battery of steel plates-electrodes separated by rubber rings. The internal cavity of the battery is half filled with an aqueous solution of KOH or NaOH. A constant voltage applied to the plates causes the electrolysis of water and the release of gaseous hydrogen and oxygen.
This mixture is discharged through a PVC tube put on the fitting into an intermediate container, and from it into a water lock, which are made from two empty cartridges for refueling gas lighters (cans of the Severny Press plant in Leningrad can be used). The gas that has passed through a mixture of water and acetone placed there in a ratio of 1: 1 has the composition necessary for combustion and, diverted by another tube into the nozzle - a needle from a medical syringe, burns out at its outlet with a temperature of about 1800 ° C.
Rice. 1. Water burner.
For the electrolyzer boards, I used thick plexiglass, 25 mm thick. This material is easy to process, chemically resistant to the action of the electrolyte and allows you to visually control its level in order to add distilled water through the filling hole if necessary.
Plates can be made from sheet metal (stainless steel, nickel, pickled or transformer iron) with a thickness of 0.6-0.8 mm. For ease of assembly, round recesses are squeezed out in the plates for the rubber seal rings, their depth with a ring thickness of 5-6 mm should be 2-3 mm.
Rings designed to seal the internal cavity and electrically insulate the plates are cut from sheet oil and petrol resistant or acid resistant rubber. It is not difficult to do this manually, but it will still be ideal to do it with a round cutter.
The four M8 steel studs connecting the parts are insulated with 10mm cambric and threaded into matching 11mm holes.
The number of plates in the battery is 9. It is determined by the parameters of the power supply unit: its power and maximum voltage - at the rate of 2 V per plate. The current consumed depends on the number of plates involved (the fewer of them, the greater the current) and on the concentration of the alkali solution. In a more concentrated solution, the current is less, but it is better to use a 4-8% solution - it does not foam so much during electrolysis.
The contact terminals are soldered to the first and last three plates. A standard charger for car batteries VA-2, connected to 8 plates, at a voltage of 17 V and a current of about 5 A, provides the necessary performance of the combustible mixture for the nozzle - a needle with an internal 0.6 mm. The optimal ratio of the diameter of the nozzle needle and the performance of the electrolyzer is established empirically - so that the ignition zone of the mixture is located outside the needle. If the productivity is low or the diameter of the hole is too large, combustion will begin in the needle itself, which will quickly heat up and melt from this.
A reliable barrier against the spread of flame through the supply tube inside the electrolyzer is the simplest water lock, which is made from two empty cartridges for refilling gas lighters. Their advantages are the same as those of the board material: ease of machining, chemical resistance and translucency, which allows you to control the liquid level in the water seal. The intermediate tank eliminates the possibility of mixing the electrolyte and the composition of the water seal in intensive operation modes or under the action of a vacuum that occurs when the power is turned off. And in order to avoid this for sure, at the end of work, you should immediately disconnect the tube from the electrolyzer. The fittings of the containers are made of copper tubes 4 and 6 mm, they are installed in the upper wall of the cans on the thread. Through them, the composition of the water seal is filled and the condensate is drained from the separation tank. An excellent funnel for this will come from another empty spray can, cut. in half and with a thin tube installed in place of the valve.
Connect the electrolytic cell with an intermediate container with a short 5 mm polyvinyl chloride tube, the latter with a water seal, and its outlet fitting with a longer tube with a needle nozzle (You can use a medical syringe with a needle as a nozzle). Inside the handle (syringe) is placed a fire-extinguishing packing - a brass mesh coiled into a spiral.
Rice. 2. Electrolyzer device:
1 - insulating PVC tube 10 mm, 2 - M8 stud (4 pcs.), 3 - M8 nut with washer (4 pcs.), 4 - left board, 5 - plug-bolt M10 with washer, 6 - plate, 7 - rubber ring, 8 - fitting, 9 - washer, 10 - PVC tube 5 mm, 11 - right board, 12 - short fitting (3 pcs.), 13 - intermediate tank, 14 - base, 15 - terminals, 16 - bubble tube , 17 - nozzle-needle, 18 - water lock body.
Turn on the rectifier, adjust the voltage or the number of connected plates to the rated current and ignite the gas coming out of the nozzle.
If you need more performance - increase the number of plates and use a more powerful power supply - with a LATR and a simple rectifier. The flame temperature is also amenable to some adjustment by the composition of the water seal. When it contains only water, the mixture contains a lot of oxygen, which in some cases is undesirable. By pouring methyl alcohol into the water lock, the mixture can be enriched and the temperature raised to 2600 ° C. To reduce the flame temperature, the water lock is filled with a mixture of acetone and water in a ratio of 1: 1. However, in the latter cases, one should not forget to replenish the contents of the water lock.
Yu. ORLOV, Troitsk, Moscow region
Posted by: Modeller Constructor
An electrolyser is a special device that is designed to separate the components of a compound or solution using an electric current. These devices are widely used in industry, for example, to obtain active metal components from ore, to purify metals, to apply metal coatings to products. For everyday life, they are rarely used, but also found. In particular, for home use, devices are offered that allow you to determine the contamination of water or get the so-called "living" water.
The basis of the operation of the device is the principle of electrolysis, the discoverer of which is considered to be the famous foreign scientist Faraday. However, the first water electrolyzer 30 years before Faraday was created by a Russian scientist named Petrov. He proved in practice that water can be enriched in the cathode or anode state. Despite this injustice, his work was not in vain and served the development of technology. At the moment, numerous types of devices have been invented and successfully used that work on the principle of electrolysis.
What is it
The electrolyzer works thanks to an external power source that supplies electric current. Simplified, the unit is made in the form of a housing in which two or more electrodes are mounted. Inside the case is an electrolyte. When an electric current is applied, the solution decomposes into the required components. Positively charged ions of one substance are directed to a negatively charged electrode and vice versa.
The main characteristic of such units is performance. That is, this is the amount of solution or substance that the installation can process in a certain period of time. This parameter is indicated in the model name. However, it can also be influenced by other indicators: current strength, voltage, type of electrolyte, and so on.
Species and types
According to the design of the anode and the location of the current conductor, the electrolyzer can be of three types, these are units with:
- Pressed baked anodes.
- A continuous self-baking anode, as well as a side conductor.
- Continuous self-baking anode, as well as the upper conductor.
The electrolyzer used for solutions, according to design features, can be divided into:
- Dry.
- Flowing.
- Membrane.
- Diaphragm.
Device
The designs of the units may be different, but they all work on the principle of electrolysis.
The device in most cases consists of the following elements:
- Electrically conductive body.
- Cathode.
- Anode.
- Branch pipes designed for electrolyte input, as well as for the output of substances obtained during the reaction.
The electrodes are sealed. Usually they are presented in the form of cylinders that communicate with the external environment using nozzles. The electrodes are made of special conductive materials. A metal is deposited on the cathode or ions of the separated gas are directed to it (during the splitting of water).
In the non-ferrous industry, specialized units for electrolysis are often used. These are more complex installations that have their own characteristics. Thus, an electrolyzer for extracting magnesium and chlorine requires a bath made of end and longitudinal walls. It is lined with refractory bricks and other materials, and is also divided by a partition into a compartment for electrolysis and a cell in which the final products are collected.
The design features of each type of such equipment make it possible to solve only specific problems that are associated with ensuring the quality of released substances, the speed of the reaction, the energy intensity of the installation, and so on.
Operating principle
In electrolysis devices, only ionic compounds conduct electricity. Therefore, when the electrodes are lowered into the electrolyte and the electric current is turned on, an ionic current begins to flow in it. Positive particles in the form of cations are sent to the cathode, for example, these are hydrogen and various metals. Anions, that is, negatively charged ions flow to the anode (oxygen, chlorine).
When approaching the anode, anions lose their charge and become neutral particles. As a result, they settle on the electrode. Similar reactions occur at the cathode: cations take electrons from the electrode, which leads to their neutralization. As a result, cations settle on the electrode. For example, when water is split, hydrogen is formed, which rises up in the form of bubbles. To collect this gas, special pipes are constructed above the cathode. Through them, hydrogen enters the necessary container, after which it can be used for its intended purpose.
The principle of operation in the designs of different devices is generally similar, but in some cases there may be some peculiarities. So in membrane units, a solid electrolyte is used in the form of a membrane, which has a polymer base. The main feature of such devices lies in the dual purpose of the membrane. This interlayer can transport protons and ions, including separating electrodes and end products of electrolysis.
Diaphragm devices are used in cases where diffusion of the end products of the electrolysis process cannot be allowed. For this purpose, a porous diaphragm is used, which is made of glass, asbestos or ceramics. In some cases, polymer fibers or glass wool can be used as such a diaphragm.
Application
The electrolyzer is widely used in various industries. But, despite the simple design, it has various versions and functions. This equipment is used for:
- Mining of non-ferrous metals (magnesium, aluminum).
- Obtaining chemical elements (decomposition of water into oxygen and hydrogen, obtaining chlorine).
- Wastewater treatment (desalination, disinfection, disinfection from metal ions).
- Processing of various products (milk demineralization, meat salting, electroactivation of food liquids, extraction of nitrates and nitrites from vegetable products, protein extraction from algae, mushrooms and fish waste).
In medicine, the units are used in intensive care to detoxify the human body, that is, to create high-purity sodium hypochlorite solutions. For this, a flow-through device with titanium electrodes is used.
Electrolysis and electrodialysis plants are widely used to solve environmental problems and water desalination. But these units, in view of their shortcomings, are rarely used: this is the complexity of the design and their operation, the need for a three-phase current and the requirement for periodic replacement of electrodes due to their dissolution.
Such installations are also used in everyday life, for example, to obtain “living” water, as well as to purify it. In the future, it is possible to create miniature plants that will be used in cars for the safe production of hydrogen from water. Hydrogen will become a source of energy, and the car can be filled with ordinary water.
