Mixing of ozone and water:

Ozone is a kind of gas. Only by dissolving ozone into water, making the water contain a certain concentration of ozone, and maintaining a certain reaction time, can the purpose of sterilization and disinfection be achieved. Commonly used methods of mixing ozone and water are bubbling method, jet method, mixing pump and so on.

To make the water reach a certain ozone concentration, in addition to ensuring that the ozone generator has sufficient ozone production and concentration, it is also necessary to ensure the efficiency of gas-liquid mixing. The CT value recommended by the ozone industry is 1.6, C is the ozone water-soluble concentration (mg/L), T is the reaction time (min), the most economical operation is the ozone water-soluble concentration of 0.4mg/L, and the reaction time is 4min.

The first type: bubbling method

The bubbling method is to pass the ozone gas produced by the ozone generator to the bottom of the oxidation tower or oxidation tank through a pipeline, and emit microbubbles through the microcavity bubbler. The bubbles dissolve the ozone in the water during the rising process. The efficiency of mixing ozone by bubbling method is generally 20-30%.

The bubbling of oxidation tower used in general water purification treatment has the following characteristics:

1. The oxidation tower is generally made of stainless steel and has two open windows to observe the size and uniformity of the bubbles.

2. The oxidation tower is equipped with an anti-backflow device, that is, the ozone gas needs to go around the top of the oxidation tower and then enter the bubbler at the bottom of the tower to prevent the water stored in the oxidation tower from entering the ozone generator by self-pressure after the ozone generator stops working.

3. Air is distributed at the bottom of the oxidation tower, the bubblers are evenly distributed, the material is anti-oxidation titanium or corundum, and the filter aperture of the bubbler should be small to produce microbubbles.

4. Water enters at the upper side of the oxidation tower, and water comes out at the lower end. The water flows through the oxidation tower from top to bottom and forms a countercurrent with the ozone bubbles in the gas phase to improve mixing efficiency.

5. There is an overflow port at the top of the oxidation tower to prevent unbalanced water in and out; a sewage outlet at the bottom.

6. The middle and upper part should be equipped with a liquid level display to facilitate the observation of the water level in the oxidation tower.

7. The size of the oxidation tower must ensure a large height-to-diameter ratio. Even if the oxidation tower has a small amount of treated water, its effective height must not be less than 2 meters.

The second method: jet method

The jet method is to form negative pressure in the air cavity in the jet under the action of high-speed water flow, suck in ozone gas, and then pulverize the ozone gas by the high-speed water flow to form microbubbles and fully contact and mix with water. The efficiency of mixing ozone by the jet method is generally 25-40%.

The problems that should be paid attention to when using jet method for gas-liquid mixing are as follows:

1. The inlet and outlet sections of the ejector require a higher pressure difference, which is not less than 0.2 Mpa. Generally, a booster pump is installed in front of the ejector.

2. The air inlet section of the ejector must have very reliable measures to prevent backflow, generally with double or triple protection devices.

3. The effluent of the jet cannot be filled directly. Although it is possible that the water-soluble concentration can reach the specified value, the reaction time is too short, which will affect the sterilization effect.

4. The best application method of the ejector is to use it in conjunction with the reaction tank. The booster pump feeds water from the lower side of the reaction tank to the ejector, and the water from the ejector enters the reaction tank from the tangential direction of the lower side of the reaction tank. Ozone is added, and the water flow with ozone bubbles spirally rises in the reaction tank, which increases the mixing efficiency.

5. The ejector and booster pump should be determined according to the generator's air output and system water pressure. The ozone generator that selects the oxygen source has high ozone concentration and small air output, which can reduce the investment of the jet and booster pump.

The third method: mixed pump method

The mixing pump is generally a vortex type, forming a negative pressure in the pump, and sucking gas (or liquid) at the suction port, and mixing of gas-liquid and liquid-liquid can be carried out through the stirring of multiple impellers. The efficiency of using a mixing pump to dissolve ozone is relatively high, generally 40-70%.

The problems that should be paid attention to when using a mixing pump for gas-liquid mixing are as follows:

1. When the gas-liquid ratio is 1:9, the mixing efficiency of the mixing pump is the best.

2. The actual water output of the mixing pump is the difference between the rated water output and the suction volume. When the suction volume of the mixing pump is increased, the water output of the pump decreases accordingly.

3. When the mixing pump is installed, a regulating valve and a pressure gauge should be added to the inlet and outlet sections to adjust the best suction volume.

4. After the water is discharged from the mixing pump, an exhaust tank or a reaction tank must be added to discharge microbubbles dissolved in water.

5. The mixing pump should not be connected to the main road. In this way, the mixing pump assumes two responsibilities for water supply and mixing, and it is difficult to guarantee both effects at the same time.