Electrolytic production technology of the hottest

2022-08-17
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Electrolytic generation technology of ozone

the method of producing ozone gas by electrolysis of oxygen-containing electrolyte with DC power supply has a long history as the discovery of ozone. Before the 1980s, electrolytes were mostly acid salt electrolytes filled in water. The electrolytic area was relatively small, the ozone production was very small, and the operation cost was very high. Because people have done a lot of research work in electrode materials, electrolyte, electrolysis mechanism and process, great progress has been made in electrolytic ozone generation technology. 6 recently, the SPE (solid polymer electrolyte) electrode developed: with the metal oxidation catalytic technology, using pure water to obtain more than 14% high concentration ozone, which makes the technology of electrochemical ozone generator take a big step forward

process

electrolytic electrochemical ozone generation is generated by electrochemical oxidation of water instead of high-frequency corona discharge of pre dried compressed air (or oxygen) like corona ozone generator. Water containing hydrated fluorescent anionic electrolyte can be oxidized to ozone at high current power at approximately room temperature. Progress in the selection of anode materials has also made electrolysis close to room temperature possible. In previous studies, the current dare rate that is attractive to ozone has only been measured in the electrolyte (or anode surface) with extremely low temperature. Operating at this temperature (-20 ~ -60 ℃), coupled with the need for expensive refrigeration, it is not allowed to use the reduction of oxygen as the corresponding cathode process in the electrolysis process. Because the kinetics of oxygen reduction in the air became very poor with the decrease of temperature, hydrogen escape was once regarded as the only available cathode process, although in theory, a cell voltage of 1.23V was required. For the electrolytic production of ozone, all the predictions are very unfavorable

the electrolysis method (Figure) discussed below is composed of the following half cell reaction. The theoretical cell voltage for ozone production at the anode is 0.27v. In fact, it has never been close to this voltage, because people must stop the escape of oxygen by using anode materials with extremely high oxygen overvoltage. Redox reactions, which have also been extensively studied in the development of fuel cells, are notoriously slow. It is estimated that the tank voltage is about 1.8 ~ 2.1V. In general, the electrolysis process becomes: O2 (air) → O3, and some characteristics and advantages can be pointed out immediately. The air sent into the reactor does not need any pretreatment, and the air does not need to be dried or compressed. In fact, it may be desirable to slightly humidify the electrolyte to prevent water loss. Carbon dioxide in the air is discharged through the selected acidic electrolyte. On the anode side, no nitrogen oxides (NOx) are produced, only the mixture of ozone, oxygen and air as the carrier. When ozone escapes from the electrolytic cell, the carrier gas (the air supplied to the electrolytic cell that exceeds the cathode stoichiometry) is used to dilute the formed ozone, otherwise, the generated ozone concentration may greatly exceed the explosion limit concentration

a unique advantage of electrolysis process: unlike corona discharge process, the concentration of ozone is independent of power consumption. The concentration of ozone first depends on the current efficiency (for which recent tests have shown that it can reach the range of 30% - 50%), and then depends on the flow of diluted gas. At least 10% ozone concentration can be achieved by electrolytic process. When the electric energy efficiency of the air source corona discharge ozone generator is lower than the concentration of approximately 1%, it is generally best not to exceed 32% ozone

development and prospects of electrolysis

since ozone was first discovered by sulfuric acid electrolysis in 1840, the development of this field has been slow, because the development results so far have been disappointing, and some are only academic

the research on the generation of ozone by electrolysis can show its characteristics in the composition of electrolyte and the selection of anode materials. This electrolyte must not react except for oxygen. Ozone escapes from the anode or oxygen is reduced. The electrolyte must also not react chemically with the generated ozone. The above limitations lead to the selection of acids containing oxygen anions and fluorescent anions, as well as their alkali metal salts, as the most suitable electrolyte

few anode materials are inert to the escape of ozone. During the anodic decomposition of water, extremely high interfacial acid concentration is produced. For most metals, high anodic potential can lead to dissolution or passivation. Platinum is commonly used, and it shows that China's Graphite reserves account for 75% of the world's total reserves, which is inert enough. Some precious metal alloys of platinum have also been used, although their oxygen overvoltage has been reduced. It has also used conductive oxides in high oxidation state (such as PbO2 and SnO2 in mouth state and evening state), which shows promising prospects. Pyrolytic carbon also appears inert in some electrolyte components

platinum/sulfuric acid anode and electrolyte have become the subject of further research in the two electrolysis methods. Initially, thin platinum wires were used to achieve a current density of 50 ~ 100A/cm2. With 0 ℃ electrolyte, the current efficiency is as high as 27% (the percentage of ozone released by the anode to oxygen), and a cell voltage of nearly 15V is still observed. Glow discharge mechanism seems to be caused by high-voltage electric field and inevitable gas heat

the second ozone generation mode studied in the platinum/sulfuric acid combination is the electrolysis of fusible electrolytic components at the lowest possible temperature. The current density is as high as 32%. However, the freezing cost (calculated according to 1/3 ~ 1/2 of the electric energy consumed by the electrolysis process itself) eliminates the consideration of industrial application of this technology

further study functions and functions in the same way: it can be used for rubber, plastic, plastic, film, textile, fiber, nano data, high molecular data, composite data, packaging tape, paper, wire and cable, optical fiber cable, safety belt, safety belt, leather belt, footwear, tape, polymer, spring steel, stainless steel (and other high hardness steel), castings, steel plates, steel strips, non-ferrous metals, auto parts The platinum anode/perchloric acid combination was studied by experiments of alloy data, other non-metallic data and metal data, such as stopping stretching, tightening, bending, tearing, 90 ° peeling, 180 ° peeling, shearing, adhesion, pull-out force, elongation and so on. However, at - 40 ℃, the maximum current efficiency is 36%, which is not suitable for proportional amplification

three different studies have made an important progress in electrolytic ozone generation using lead dioxide anode. Semchemko and others first electrolyzed phosphoric acid and found that at room temperature of 10 ~ 15 ℃, a current efficiency of 13% can be obtained

then, semchenko and his collaborators studied the application of perchloric acid and achieved a yield of 32% current efficiency at - 15 ℃. Combined with lead dioxide anode, adding a small amount of fluoride ions to the electrolyte can improve the anode potential and improve the ozone current efficiency. By 1975, encouraging results had been achieved. However, with PB02 anode, some corrosion was found in the process of ozone escape. Then Fowler and Tobias. (Fowler and Tobias) proposed a comprehensive chemical/electrochemical mechanism

Fritz et al. Continued the performance evaluation of phosphate based electrolyte system, especially the evaluation of neutral buffer system that eliminates PbO2 corrosion. The current efficiency of 13% was obtained at room temperature

Fowler and Tobias studied the use of fluorescent anion electrolyte, and still concluded that the output of PbO2 anode is much larger than that of platinum electrode. In addition, the study also found that HBF4 and HPF6 are particularly suitable for the electrolyte of ozone escape

it was found that the platinum anode in hpp6 electrolyte can also give a high ozone yield. Therefore, Fowler and Tobias proposed a principle for the selection of solutes based on the negative charge of anions. In addition, it is also found that the adsorption of electrolyte anions on the anode material is also related to the ozone current efficiency

Fowler et al. Found that a certain form of carbon, commonly known as vitrified carbon black, also has the ability to produce higher ozone current efficiency in fluorescent anion electrolyte at a temperature above 0 ℃, and the experimental stress amplitude ratio is negative. Under normal conditions corresponding to ozone escape, compressed carbon black (high surface area carbon) degraded rapidly, showing CO2 escape and structural spallation. Graphite is also destroyed due to the anion insertion between its surfaces, followed by axial expansion, and

glassy carbon black is more resistant to oxidation process and anion penetration due to its irregular and fully coordinated structure. This form of carbon black is made by heat treating certain resins under controlled inert gas protection. Corrosion was observed in oxygen ion electrolysis and in low concentrations of fluorescent anionic acids, however, there was no corrosion in high concentrations of electrolytes. This phenomenon is as incomprehensible as it happens by accident. The ozone production reaches the maximum at the high concentration of fluorescent anionic acid electrolyte

the electrolytic ozone generator has the advantages of high ozone concentration, pure components and high solubility in water. It has a wide application prospect in medical treatment, food processing and breeding industry and families. Under the condition of reducing cost and power consumption, it will form a fierce competition with the corona discharge ozone generator, which is widely used at present

the possible result of continuing efforts in the development of electrolytic ozone generator is that for all chassis components of bentler Automotive Industry Co., Ltd. and bentler Sigri, this kind of high concentration ozone generator with relatively low cost becomes applicable because its power consumption can catch up with the best air source corona discharge technology. This newly developed ozone generator can also reduce the contact cost. In addition, this process will make it as easy to enlarge and shrink the equipment. Research in this area will undoubtedly continue

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