CN102897937B - Ozone Dosing Two-step Jet Mixing Method Multistage Reactor - Google Patents

Abstract

The invention belongs to the technical field of water treatment, and in particular relates to a multistage reactor of ozone dosing two-step jet mixing method. The ozone dosing two-step jet mixing method multi-stage reactor proposed by the present invention is composed of a dosing system, a mixing chamber and a reaction chamber. The whole reactor is divided into three stages. The secondary jet for thorough mixing. The addition of ozone is also divided into three stages. The mixing of ozone in the reaction chamber is a jet mixing method, and the nozzles and guide tubes used for jet mixing are arranged horizontally. The reaction of ozone is divided into three steps. The first step is to mix the ozone with the raw water evenly through the jet mixer, and then react inside the pipeline. The second step is in the mixing chamber. The large bubbles move upward evenly during the mixing cycle and mix with the incoming water in reverse to continue the reaction. The third step is to bring the small bubbles into the lower compartment with the water flow to continue the reaction.

Description

Ozone Dosing Two-step Jet Mixing Method Multistage Reactor

technical field

The invention belongs to the technical field of water treatment, and in particular relates to a multistage reactor of ozone dosing two-step jet mixing method.

Background technique

There are two types of dosing methods, one is that ozone and water enter the contact device through their own channels, such as bubble towers, packed bubble towers, and walnut injectors, etc.; the other is that ozone and water are first mixed through a gas-water mixing device , and then enter the gas-water contact device, such as Venturi water ejector pressure injection method, fixed screw mixer, etc.

Bubble tower and packed bubble tower - In the lower part of a circular or other shaped contact tower with a height of several meters, a microporous diffusion plate composed of various materials is erected. The treated water flows from top to bottom, and ozone with a certain pressure passes through the diffusion plate from bottom to top, floating up in the form of microbubbles, so that the ozone can fully oxidize the pollutants in the water during the mass transfer process. In the packed bubble tower, a certain thickness of ceramic ring, plastic ring, corrugated plate or activated carbon is laid in the upper bubble tower space of the microporous diffusion plate to improve the gas-liquid contact conditions and increase the oxidation efficiency. The advantage of the bubble tower is that the water resistance is small, its loss can be ignored, the dosage of ozone is easy to control, and the mass transfer is good. the

The working principle of the turbine injector is that the water flows into the contact tank under the gravity state, and there is a motor in the center of the tank, which drives a rotor injector to generate negative pressure to inhale ozone. The advantages of this type are rapid gas injection, small bubbles, high contact efficiency, automatic operation, and no need to build a high contact tower. The disadvantage is that driving the motor consumes electricity.

Fixed Spiral Mixer The stationary spiral mixer is an air-water contact device consisting of a row of reverse spirals mounted in a tube. This mixer is very close to a plug flow reactor. The liquid is fully radially mixed in the tube, but there is almost no axial mixing, and the water flow contacts the ozone bubbles during the rotating and splitting movement to produce many tiny vortex turbulence. This mixer has a larger mass transfer area and faster mass transfer speed. The actual utilization rate of ozone in this mixer is higher than that of the bubble tower, but the disadvantage is that the water head loss is large.

The principle of the pressure injection method is that water under a certain pressure will inhale ozone through the negative pressure generated by a water injector and mix it with water immediately. The whole process of quality. Recently, the injection method has developed a type called the divisional injection method. The principle is to pass part of the water through the injector, inhale ozone and then mix it with the rest of the water into the contact pool. The advantage of the pressure injection method is that it does not require mechanical stirring and is suitable for use in small water plants.

Contents of the invention

The object of the present invention is to provide an ozone dosing and reaction device to achieve more uniform distribution of ozone and higher mixing efficiency of mass transfer efficiency.

The invention provides a multi-stage reactor of ozone dosing two-step jet mixing method, including a dosing system, a mixing chamber and a reaction chamber. The reactor is divided into three stages, consisting of three first mixing chambers, a first reaction chamber chamber, the second mixing chamber, the second reaction chamber, the third mixing chamber, and the third reaction chamber are sequentially connected in series; the dosing system is three parallel units, each unit consists of an ozone generator, a water ejector , nozzle and guide cylinder, the ozone in the ozone generator is mixed with water through the water injector, and then enters the guide cylinder through the nozzle; the nozzles and the guide cylinder of the three units in the dosing system are respectively located in the three mixing chambers. indoor. The nozzle and the guide cylinder are set horizontally, and the center position is 0.8~1.2m away from the bottom of the mixing chamber where they are located. The ratio of the minimum section diameter of the guide cylinder to the maximum section diameter is 0.6~0.75:1.

The part near the top of the mixing chamber is provided with a water inlet, the direction of water flow in the mixing chamber is from top to bottom, and the direction of water flow in the reaction chamber is from bottom to top. Water flows into the reaction chamber through the flow hole at the bottom of the mixing chamber. The effective water depth in each reaction chamber is not less than 4m

The water flow enters the first reaction chamber at the connection between the lower end of the first mixing chamber and the reaction chamber, then flows through the first reaction chamber from bottom to top, and enters the second mixing chamber at the connection between the top of the first reaction chamber and the second mixing chamber , and so on, the water finally flows through the water outlet provided near the top of the third reaction chamber.

An ozone dosing control valve can be arranged between the ozone generator and the plurality of ozone water injectors.

In this reactor, there is also a reflux system, including a reflux water inlet and a circulating water pump. The reflux water inlet is set at the bottom of the third reaction chamber, and is divided into three branches through the reflux pipeline to connect the three units in the dosing system. The ozone passes through the water injector. The return pipeline is divided into three branches before connecting the injectors of the three units in the dosing system, respectively passing through three flowmeters, and after passing through the injectors, respectively flowing through three circulating water volume control valves.

Further, vent holes may be provided at the connection between the top of the mixing chamber and the top of the reaction chamber.

The top of the third reaction chamber is provided with a gas outlet connected to an ozone destroyer to further remove ozone tail gas.

The whole reactor of the present invention is divided into three stages, which are respectively a primary mixing chamber, a primary reaction chamber, a secondary mixing chamber, a secondary reaction chamber; a tertiary mixing chamber, and a tertiary reaction chamber.

The ozone in the ozone generator is added to the water pipe through the water injector, and then fully mixed through the secondary jet inside the reaction chamber. the

In the present invention, the reaction of ozone is divided into three steps. The first step is that after the ozone is uniformly mixed with the raw water through the jet mixer, the reaction is carried out inside the pipeline. Due to the effect of dissolved gas, the gas-water contact effect is good and the reaction efficiency is high; the second The first step is in the mixing chamber, the large bubbles move upward evenly during the mixing cycle, and mix with the incoming water in reverse to continue the reaction; the third step is to bring the small bubbles into the lower compartment with the water flow to continue the reaction.

Beneficial effects of the present invention: Since the effective residence time of ozone in water is relatively short, within the reaction time of 20 min to 30 min, the conventional method of using aeration discs is generally divided into 3 to 4 stages of reaction, each stage including an up and down reciprocating process, Aeration trays are arranged at each stage according to calculation needs. The present invention is divided into three levels according to the water volume, reducing the complexity of the reactor structure. Each stage is equipped with a jet mixer. The whole process of ozone is added according to the demand. The demand in the front stage is large, and the dosage is also large. The demand in the middle and rear stages is reduced, and the dosage is also reduced accordingly. The whole process ensures that the residual amount of ozone in the exhaust gas is as small as possible. Therefore, compared with conventional engineering application devices, the present invention has simplified structure, more uniform ozone distribution, further improved mass transfer efficiency, and less residual ozone in tail gas.

Description of drawings

Fig. 1 is a schematic diagram of the structure of the present invention.

Numbers in the figure: 1 is the water inlet, 2 is the first mixing chamber, 3 is the guide tube, 4 is the flow hole, 5 is the first reaction chamber, 6 is the second mixing chamber, 7 is the second reaction chamber, 8 1 is the third mixing chamber, 9 is the third reaction chamber, 10 is the outlet pipe, 11 is the vent hole, 12 is the ozone destroyer, 13 is the nozzle, 14 is the circulating water control valve, 15 is the ejector, 16 is the flow meter, 17 Add control valve for ozone, 18 is the ozone main pipe, 19 is the water return pipe, 20 is the circulating water pump, 21 is the ozone generator, and 22 is the backflow suction port. the

Detailed ways

Example 1

Two-step jet mixing method multi-stage reactor:

The reactor includes a dosing system, a mixing chamber and a reaction chamber. The reactor is divided into three stages, consisting of three first mixing chamber 2, first reaction chamber 5, second mixing chamber 6, second reaction chamber 6, and third mixing chamber. The chamber 8 and the third reaction chamber 9 are formed in series in sequence; the dosing system is three parallel units, each unit is composed of an ozone generator 21, a water injector 15, a nozzle 13 and a guide tube 3, and the ozone generator 21 The ozone in the water is mixed with water through the water injector 15, and then enters the guide tube 3 through the nozzle 13; the nozzle 13 and the guide tube 3 of the three units in the dosing system are respectively located in the three mixing chambers; the nozzle 13 and the guide tube 3 are respectively located in the three mixing chambers; The guide tube 3 is arranged horizontally, and its center is 1.0m away from the bottom of the mixing chamber where it is located. The ratio of the minimum section diameter to the maximum section diameter of the guide tube 3 is 0.65:1.

The water flow enters the reaction chamber 5 at the connection between the lower end of the mixing chamber 2 and the reaction chamber 5, then flows through the reaction chamber 5 from bottom to top, and enters the mixing chamber 6 at the connection between the top of the reaction chamber 5 and the mixing chamber 6, and so on. Water flows out of the water outlet 10 provided near the top part of the reaction chamber 9 . The water depth in each reaction chamber was 4.2 m.

An ozone dosing control valve 17 can be arranged between the ozone generator 21 and the plurality of ozone water injectors 15 .

The reactor is additionally provided with a reflux system, including a reflux water intake 22 and a circulating water pump 20. The reflux water intake 22 is arranged at the bottom of the reaction chamber 9, and is divided into three branches through the reflux pipeline to connect the ozone of the three units in the dosing system respectively. Via injector 15. The return pipe is divided into three branches before connecting the injectors 15 of the three units in the dosing system, respectively passing through three flowmeters 16, and after passing through the injectors 15, respectively flowing through three circulating water volume control valves 14.

Ventilation holes are arranged at the connection between the top of the mixing chamber and the top of the reaction chamber. The top of the third reaction chamber 9 is provided with an air outlet connected to an ozone destroyer 12 to further remove ozone tail gas.

Example 2

The reactor pilot plant shown in Example 1 was used to carry out the ozone oxidation test of slightly polluted raw water, and the treatment capacity was 100 t/d. Taking nitrobenzene as the characteristic pollutant, the initial concentration is 500mg/L. The dosing concentration of ozone is 10mg/L, and when the hydraulic retention time is 30min, the removal rate of nitrobenzene is 58%, and the utilization rate of ozone is 92%. The jet mixing device in the pilot plant was removed, and the aeration method was changed to a titanium alloy aerator head. Under the same operating conditions, the nitrobenzene removal rate of the aerator head method was 49%, and the ozone utilization rate was 80%. ; Therefore, the efficiency and ozone utilization rate of the jet mixing reactor are significantly higher than the aeration methods commonly used now.

Example 3

The reactor pilot plant shown in Example 1 is used to carry out the ozone oxidation test of slightly polluted raw water, the treatment capacity is 100t/d, the raw water COD _Mn is 6.0mg/L, and the ratio of the minimum cross-sectional diameter of the draft tube to the maximum cross-sectional diameter It is 0.65:1. When the angles between the axis of the guide cylinder and the horizontal line are 0°, 45°, and 90°, the ozone utilization rates are 92%, 90%, and 87%, respectively. When the ratio of the minimum section diameter to the maximum section diameter of the guide tube is 0.3, 0.6, 0.8, and 1.0, the utilization rates of ozone are 85%, 91%, 90%, and 89%, respectively. Therefore, the ratio of the minimum section diameter to the maximum section diameter of the draft tube is 0.6~0.75:1, and when the axis is horizontal, the ozone utilization rate is the highest.

Claims (10)

1. Ozone dosing two-step jet mixing method multi-stage reactor, including dosing system, mixing chamber and reaction chamber, is characterized in that: The reactor is divided into three stages, consisting of the first mixing chamber (2), the first reaction chamber (5), the second mixing chamber (6), the second reaction chamber (7), the third mixing chamber (8) , the third reaction chamber (9) are connected in series; the dosing system is three parallel units, each unit consists of an ozone generator (21), a water injector (15), a nozzle (13) and a guide The ozone in the ozone generator (21) is mixed with water through the water injector (15), and then enters the guide tube (3) through the nozzle (13); the three units in the dosing system The nozzle (13) and the guide tube (3) are respectively located in the three mixing chambers; the nozzle (13) and the guide tube (3) are arranged horizontally. 2. The ozone dosing two-step jet mixing method multi-stage reactor according to claim 1, characterized in that a water inlet (1) is provided near the top of the first mixing chamber (2), and the mixing chamber ( The direction of water flow in 2, 6, 8) is from top to bottom, and the direction of water flow in reaction chambers (5, 7, 9) is from bottom to top; the effective water depth in each reaction chamber is not less than 4m. 3. The ozone dosing two-step jet mixing method multi-stage reactor according to claim 2, characterized in that the water flows into the reaction chamber through the flow hole (4) at the bottom of the mixing chamber. 4. The ozone dosing two-step jet mixing method multi-stage reactor as claimed in claim 1, characterized in that the center position of the nozzle (13) and the guide tube (3) is 0.8~ 1.2m, the ratio of the minimum section diameter to the maximum section diameter of the guide tube (3) is 0.6~0.75:1. 5. The ozone dosing two-step jet mixing method multi-stage reactor according to claim 2, characterized in that the water flow enters at the connection between the lower end of the first mixing chamber (2) and the first reaction chamber (5) The first reaction chamber (5), then flows through the first reaction chamber (5) from bottom to top, and enters the second mixing chamber (6) at the connection between the top of the first reaction chamber (5) and the second mixing chamber (6) , and so on, the water finally flows out through the water outlet (10) provided near the top part of the third reaction chamber (9). 6. The ozone dosing two-step jet mixing method multi-stage reactor as claimed in claim 1, characterized in that ozone dosing Add control valve (17). 7. The ozone dosing two-step jet mixing method multi-stage reactor according to claim 1, characterized in that the reactor is also provided with a reflux system, including a reflux suction port (22) and a circulating water pump (20), The backflow suction port (22) is set at the bottom of the third reaction chamber (9), and is divided into three branches through the backflow pipe to connect the water injectors (15) of the three units in the dosing system respectively. 8. The ozone dosing two-step jet mixing method multi-stage reactor as claimed in claim 7, is characterized in that described return pipeline is divided into three branch roads and connects respectively the injector (15) of three units in the dosing system ) before passing through three flowmeters (16), and after passing through the water ejector (15), respectively flowing through three circulating water volume control valves (14). 9. The ozone dosing two-step jet mixing method multi-stage reactor as claimed in claim 1, characterized in that the connection between the top of the mixing chamber and the top of the reaction chamber is provided with air holes. 10. The ozone dosing two-step jet mixing method multi-stage reactor according to claim 1, characterized in that the top of the third reaction chamber (9) is provided with a gas outlet connected to an ozone destroyer (12).