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Identification and selection of ozone equipment in my environmental diary


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Ozone industry in China through several decades of wind and rain, has rapid development and progress, the applications of large span, including wastewater treatment, waste gas treatment, food sterilization bleaching, space, sterilization, water sterilization, chemical products, such as oxidation, the increasing market demand, to achieve the highest peak in recent decades.

With the gradual popularity of ozone generator, application fields throughout all walks of life, the application of ozone professional knowledge is limited, unavoidably there is no good ozone production suppliers to exploit loopholes, to small charge big, the use of unethical competition means to deceive consumers, so as to seek illegal profits.

This writing is intended to guide the consumer, the matters that should be paid attention to when purchasing industrial ozone generator, standing on in the best interest of consumers, in a simple and convenient way of observing monitoring industrial ozone generator, the choose and buy avoid due to the lack of personal professional knowledge or deceptive intentionally mislead others, but wrong to buy industrial ozone generator.

A case                                                                                                           

Practical case: a textile printing and dyeing enterprise due to the increase of output, resulting in the old sewage treatment system load is too high, daily treatment of 3,000 tons of wastewater, during the transformation of the old process, the design of 3000g/h ozone generator after wastewater decolorization project.
Due to the lack of knowledge of ozone generator, the printing and dyeing enterprise purchased equipment with 3000g/h output on the nameplate at a higher price than the market, but only 1000g/h ozone equipment.

Field measured data:

Gas volume 85m³/h, concentration unmeasured, pressure 0.06mpa, single-phase current 14A.
The simplest and most direct way to determine ozone production is to calculate power in terms of current.
Judging from the current value alone, the power of the machine is less than 10KW, and even the most advanced international technology only reaches 600g/h output.


Identification method of ozone yield

Ozone generator according to the air source system can be divided into air source ozone system and oxygen source ozone system. Air source ozone system configuration for air compressor, freeze dryer, adsorption dryer, four filters;
Oxygen source ozone system configuration is basically air compressor, freeze dryer, multistage filter, oxygen generator system (when using oxygen tank as oxygen source, no need for the above mechanical equipment), the parameters that affect the output of ozone generator are based on 6 points: concentration, gas volume, pressure, power, current, temperature. The six items of data complement each other and are indispensable. Each of these data will affect the actual output of the ozone generator.
Ozone production (g/h) = concentration x gas (standard atmospheric pressure)
Ozone equipment reaction chamber generally has a certain pressure, then ozone generator output (g/h) = concentration × gas volume × absolute pressure (1 standard atmospheric pressure).
According to the formula, the actual output of ozone is determined by concentration, gas volume and pressure. Most ozone generator manufacturers in the equipment configuration, there are intake rotor flowmeter, cavity pressure gauge, three-phase ammeter, can be used to judge the naked eye gas, pressure, current.

Three, ozone generator parameters detailed explanation

Concentration: ozone concentration according to the specifications of the equipment, structure and discharge parameters, ozone concentration monitoring, can be determined according to the ozone concentration detection instrument, more accurate way, under the condition of iodine method and other chemical titration monitoring. A unit of ozone concentration in mg/L or g/m³.
At present, there are three kinds of technical cavities which are more popular in China: quartz glass tube, enamel tube and plate ozone.
The international top ozone technology adopts quartz glass tube cavity, the average concentration of ozone generator in the air source system of this technology is 25mg/L; The average concentration of ozone generator in oxygen source system is 120mg/L. When using liquid oxygen as gas source to supply ozone generator, the average concentration of ozone can reach more than 150mg/L. The ozone concentration of enamel tube technology is slightly lower, and the ozone concentration of plate is even less noticeable.
In order to meet the market demand, some ozone manufacturers hype that the ozone concentration of their production can reach hundreds or even hundreds of mg/L. According to the current level of China's ozone industry, there are only a few ozone manufacturers in China that can achieve hundreds of ozone concentration under the same output and gas volume unchanged.
Gas volume: ozone gas unit m³/h or L/min (1m³/h=1000L/60min). The amount of gas can be observed and judged by the rotor flowmeter. Most of the flow on the flowmeter is the flow under absolute pressure (one standard atmospheric pressure), so the actual ozone generator gas output under a standard atmospheric pressure should be: the flowmeter shows the gas reading x (the pressure gauge shows the gas degree +1).
For example: ozone generator flowmeter shows 10m³/h, pressure gauge shows 0.08mpa (0.1mpa = 1kg), then the actual ozone gas output under a standard atmospheric pressure =10× (0.8+1) =18m³/h.

According to the formula, under the condition of constant yield, gas volume increases, concentration decreases, gas volume decreases, concentration increases. Similarly, for the same ozone equipment, the rest of the control is unchanged, only adjust its gas volume (the flow meter is basically equipped with an adjustable valve), the concentration also changes.

Fang116: Due to the lack of professionalism, consumers often mistake the flowmeter display as the actual ozone gas output, thus deceiving the real concentration and output of the equipment.

Pressure: can be judged by pressure gauge. Under certain pressure conditions, ozone power supply is more likely to discharge to stimulate ozone, so the higher the pressure of ozone generator reaction chamber, the higher the ozone concentration, the higher the current. Controlling the pressure of the ozone reaction chamber is intended to control its discharge current. Unit of ozone pressure (Mpa), 0.1Mpa=1 kg. This pressure refers to the internal pressure of the reaction chamber of the equipment at one atmosphere pressure, so the calculation of ozone volume should be set at one atmosphere pressure.

According to the above relationship, output = concentration × gas volume × pressure, for example: the concentration of an ozone equipment is 80mg/L, the gas rotormeter shows 2m³/h, the pressure gauge shows 0.07mpa, then the actual output of the equipment is 80×2× (0.7+1) =272g/h.

Power: Large industrial ozone generator power supply is 380V 50HZ, the current discharge power supply is divided into power frequency (50HZ), medium frequency (≤1000HZ) and high frequency (> 1000HZ) inverter power supply.

Fang116: The ozone generator with the highest discharge efficiency in the world basically adopts high-frequency inverter power, and the output of 1kg (1000g) air source ozone generator power basically keeps at about 16KW; The output of 1kg oxygen source ozone generator power is basically maintained at about 8KW.

Current: Calculation method is as follows:

Single-phase current (A) = power ÷220V

Three-phase current (A) = power ÷380V÷√3.

The most effective and efficient way for users to determine ozone production is to measure the supply current. Current clamp meter can be used to analyze and judge. (Note: Ammeter basically has the difference of power factor, the current displayed in this table often cannot accurately indicate the measured current parameters)

From the fourth point, we can convert: the output of 1kg air source ozone generator current is basically maintained at 25A; Production of 1kg oxygen source ozone generator current basically maintained at 13A.

When ozone production is different, the output and current are directly proportional. Such as: air source 1kg/h ozone generator current 25A, then air source 500g/h ozone generator current 13A. The same is true for power.

Fang116: When a salesman of ozone equipment tells you that their equipment produces 1kg of electricity consumption is much lower, and how to save electricity, then please expose his lies.

Temperature: due to the discharge process, ozone reaction chamber will produce a certain temperature, too high temperature, will accelerate the decomposition of ozone, so the standard concentration and standard yield can not be reached. Under normal circumstances, the ozone generator in the normal operation of the temperature rise of 5 degrees/hour.

At present, domestic cooling methods for ozone reaction chamber are divided into air cooling and water cooling. The air cooling effect often causes poor heat dissipation, low ozone concentration and low ozone yield. Industrial ozone generators, no matter small, medium or large equipment, all use water cooling to heat the ozone reaction chamber. The better the cooling, the closer you get to meeting the ozone concentration and yield targets.

Iv. Ozone treatment wastewater case data

1, sterilization cases

Sterilization experiment of wastewater from a hospital:

Ozone concentration: 100mg/L

Ozone flow: 1L/min

Experimental water volume: 500ML

Experimental method: static experiment, through aeration to dissolve gas and water mixture. The experiments were 2 minutes and 4 minutes, respectively

Experimental results: the total number of bacteria in raw water was 6.35*106 /L, the total number of bacteria in raw water was 110 /L for 2 minutes, and the total number of bacteria in raw water was 20 /L for 4 minutes. The ozone sterilization efficiency reached 99.99968%.

Case study: ozone has strong sterilization effect and no selectivity. The increase of adding time indicates that the amount of ozone increases and the sterilization efficiency increases.

2, ozone decolorization and COD removal

A. Papermaking wastewater:

Water: 10 t/H

Ozone dosage: 1000g/h (air source)

Stay time: 1h

Treatment effect: the naked eye is basically colorless, and COD degrades from 400ppmI to 200ppm

The result data are as follows: COD:O3=2:1, and the removal rate reaches 50%

B. A printing and dyeing wastewater:

Quantity: 400 m after a/D

Ozone dosage: 1200g/h (air source)

Residence time: SBR treatment, 6 hours

Treatment effect: the naked eye is basically colorless, and COD degrades from 130ppm to 102ppm

Treatment results: COD:O3=2:1, the removal rate of 22%

C. Textile wastewater:

Quantity: 120 m after/h

Ozone dosage: 4000g/h (oxygen source)

Residence time: 30min

Treatment effect: basically colorless by naked eye, COD degraded from 100ppm to 50ppm, aniline degraded from 1.0mg/L to 0.05mg/L

Treatment results: COD:O3=1.5:1, removal rate up to 50%

Fang116: Based on the above real cases, the proportion of COD:O3=1:4 mentioned in various literatures needs to be considered. The actual cases fully demonstrate that the application of ozone in wastewater treatment is not that high, and the investment cost and operation cost of treatment are not that high either. At the same time, in the case of little difference in water, due to different water quality, the amount of ozone is not the same, the treatment effect is also different. At the decolorization end, ozone has the same decolorization effect.