CN201505512U - A gas-water mixing cleaning device for submerged hollow fiber membrane modules - Google Patents

Abstract

The utility model discloses an air-water mixing cleaning device for submerged hollow fiber membrane modules, which comprises fiber membrane modules submerged in a water tank. The upper water outlet and the lower water outlet of the fiber membrane module are connected to the suction pump through the pressure gauge and the control valve through the water collection pipe, and the lower side air inlet of the fiber membrane module is connected to the suction pump through the aeration pipe through the control valve and the pressure gauge. The air compressor is connected, and the upper side port of the fiber membrane module is connected to the circulating pump through the circulating water pipe and the control valve; this design allows the gas-liquid kinetic energy to be completely converted into the mechanical energy of the membrane filament vibration, effectively slowing down the occurrence of membrane fouling and prolonging the membrane cleaning cycle ; and the operation of the circulation pump increases the cross-flow rate on the membrane surface, enhances the power of liquid flow, accelerates the flow rate of liquid rise, and intensifies the gas-water circulation, which scours the surface of the membrane filament well and prevents the extreme concentration difference on the membrane surface of the membrane module. change.

Description

A gas-water mixing cleaning device for submerged hollow fiber membrane modules

technical field

The utility model relates to water treatment equipment, in particular to an air-water mixing cleaning device used for submerged hollow fiber membrane modules.

Background technique

The submerged hollow fiber membrane device is generally a curtain type membrane module and the hollow fiber membrane filaments are distributed vertically. The submerged hollow fiber membrane device is generally used in the MBR process. MBR is divided into two types: external type and integrated type. The external MBR adopts a hollow fiber membrane module with a shell, and adopts the gas-water mixed external MBR process to form a gas-liquid two-phase flow in the membrane module, so that the gas-liquid two-phase flow quickly flows through the surface of the membrane filament, improving the membrane surface. Cross-flow rate, effectively prevent membrane fouling. However, this design is one-sided water intake, uneven water distribution, and non-immersed structure, which is limited by the occupied area.

The one-piece MBR structure generally adopts a curtain-type membrane module without a casing or distributes the hollow fiber membranes vertically, but the defect of this design is that there is no casing, which will cause mechanical damage to the membrane filaments, and it is easy to cause airflow dispersion during air washing, which cannot Membrane filaments are fully vibrated, chemical agents are easy to diffuse during chemical backwashing, reducing the effect of chemical backwashing, and the above-mentioned design has low membrane flux and poor cleaning effect, which will speed up membrane fouling.

The integrated MBR structure also uses a membrane module with a shell, which can be directly installed in the water body to be treated. Its operation methods include: 1. Working state, backwashing state, air bubble scrubbing state, and sewage discharge state; 2. Working state, backwashing state; Washing plus bubble scrubbing status, bubble scrubbing status, sewage discharge status; 3. Working status, chemical backwashing status, bubble scrubbing status, sewage discharge status. This design can reduce investment costs, but because there is no air flow in the working state, the membrane filaments cannot be shaken continuously to slow down the occurrence of membrane fouling. However, the device relies on the height difference of the internal and external mixed liquid as the driving force of the circulating flow in the membrane module to accelerate the cross-flow rate on the surface of the membrane filament. Since the height difference between the internal and external mixed liquid of the membrane module is basically less than 3 meters of water pressure, if it is operated for a long time, The concentration polarization on the surface of the membrane filament will be very serious, which will affect the membrane flux and accelerate membrane fouling.

Contents of the invention

In order to overcome the deficiencies of the prior art, the utility model provides a gas-water mixing cleaning device for submerged hollow fiber membrane modules

The technical scheme that the utility model solves its technical problem adopts is:

A gas-water mixing cleaning device for a submerged hollow fiber membrane module, including a fiber membrane module submerged in a water tank, the cleaning device is a submerged cleaning device, and adopts a column-type external pressure hollow fiber membrane module. The fiber membrane The upper water outlet and the lower water outlet of the module are connected to the suction pump through the water collecting pipe through the pressure gauge and the control valve, and the lower side air inlet of the fiber membrane module is connected to the air compressor through the control valve and the pressure gauge through the aeration pipe. The upper side port of the fiber membrane module is connected with the circulating pump through the circulating water pipeline and the control valve.

The beneficial effects of the utility model are: the design makes the gas-liquid kinetic energy completely converted into the mechanical energy of the membrane filament vibration, effectively slowing down the occurrence of membrane pollution and prolonging the membrane cleaning cycle; and the operation of the circulating pump increases the cross-flow rate on the membrane surface, Enhance the power of liquid flow, accelerate the flow rate of liquid rising, intensify the air-water circulation, wash the surface of the membrane filament well, and prevent the concentration polarization of the inner membrane surface of the membrane module; moreover, the installation is extremely convenient, and can be placed directly on the surface of the membrane to be treated In the water body, there is no need to provide an additional installation site, and with the existence of the shell, the chemical agent can be stored in the membrane module during chemical backwashing, reducing the amount of chemical agent and making it difficult for the chemical agent to diffuse out; effectively avoiding the membrane filament mechanical injury.

Description of drawings

Below in conjunction with accompanying drawing and embodiment the utility model is further described.

Fig. 1 is a structural representation of the utility model;

Detailed ways

Referring to Fig. 1, a gas-water mixing cleaning device for submerged hollow fiber membrane modules includes a fiber membrane module 1 submerged in a water tank 3, and a plurality of water inlets are arranged on the circumference of the lower end of the shell 2 of the fiber membrane module 1 14. It is characterized in that: the upper water outlet 11 and the lower water outlet 11' of the fiber membrane module 1 are connected to the control valve 9 and the suction pump 17 through the water collection pipe 4 through the pressure gauge 7, and the lower side of the fiber membrane module 1 The air inlet 12 is connected to the air compressor 18 through the aeration pipe 5 through the control valve 10 and the pressure gauge 8 , and the upper side port 13 of the fiber membrane module 1 is connected to the circulating pump 16 through the circulating water pipeline 6 and the control valve 15 .

The process of the utility model is: the fiber membrane module 1 is completely submerged in the water tank 3, the water enters the membrane module evenly through many water inlets 14 on the shell 2 of the fiber membrane module 1, the control valve 10 is opened, and the water from the membrane module inlet 12 is opened. The compressed air is blown in, and the compressed air forms a multi-beam air flow, which fully oscillates and scrubs the outer wall of a large number of membrane filaments with air. At the same time, the existence of air-water mixing makes the gas-liquid fully mixed to form a gas-liquid two-phase flow. The turbulence of the gas-liquid mixture in the membrane shell completely converts the kinetic energy of the gas-liquid into the mechanical energy of the vibration of the membrane filaments. The circulating pump 16 is connected to the cross-flow outlet 13 at the upper end of the fiber membrane module 1, and the control valve 15 is opened to speed up the hydraulic circulation in the fiber membrane module 1, and the gas and liquid flow through the membrane surface at high speed, so that the surface of the membrane filament has a larger membrane surface flow velocity , to effectively avoid concentration polarization on the outer surface of the membrane filament. Under the suction of the suction pump 17, the control valve 9 is opened to control the operation of the fiber membrane module 1 at an operating pressure of 0.008-0.03 MPa. The liquid flows along the inside of the membrane filament and flows out from the water outlet 11 or 11' of the membrane module.

Several examples are given below to illustrate the effect of the present utility model.

Example 1: Sewage is taken from a sewage plant, about 70% of which is printing and dyeing wastewater, the rest is domestic sewage, the treatment capacity is 3000m ³ /d, the influent CODcr is 700-1000, BOD ₅ is 200-300, SS 150 to 200, ammonia nitrogen between 80 and 120, and turbidity between 30 and 150. After the gas-water mixing cleaning device of the submerged hollow fiber membrane module operates in MBR mode, the removal rate of pollutants is high, and the COD is removed on average. The rate is 95%, always lower than 50mg/l, the average removal rate of ammonia nitrogen is 97%, the turbidity of the effluent is less than 0.1NTU, the energy consumption is 0.65KWh/m3, the system adopts intermittent operation mode, pumping for 20min, stopping for 1min, constant flow control, the membrane flux is controlled at 25l/m ² ·h, and it runs for 1 month, the transmembrane pressure rises from 10Kpa to 12Kpa, the membrane pressure rises slowly, and the operation is stable.

Example 2: Sewage is taken from an electroplating factory wastewater, about 90% of which is electroplating wastewater, and the rest is domestic sewage. The treatment capacity is 1000m ³ /d, the COD is 300-500, the SS is 300-500, and the turbidity is 30-500. 150, after the air-water mixing cleaning device of the submerged hollow fiber membrane module is operated in the MCR mode, the removal rate of pollutants is high, the average removal rate of COD is 95%, which is always lower than 50mg/l, and the average removal rate of SS is 98 %, the turbidity of the effluent is less than 0.1NTU, the energy consumption is 0.50KWh/m3, the system adopts intermittent operation mode, pumping for 20min, stopping for 1min, constant flow control, the membrane flux is controlled at 30l/m ² h, and it runs for 1 month , the transmembrane pressure rises from 8Kpa to 10Kpa, the membrane pressure rises slowly, and the operation is stable.

Example 3: The treated water quality is a certain river water, and high-quality direct drinking water is provided for a certain area. The turbidity of the raw water is 20-120. The removal rate of pollutants is high, the turbidity of the effluent is less than 0.1NTU, and the energy consumption is 0.50KWh/m3. The system adopts intermittent operation mode, pumping for 20 minutes, stopping for 1 minute, constant flow control, and the membrane flux is controlled at 40l/m ² ·h. After 40 days of continuous operation, the transmembrane pressure difference rose from 8Kpa to 10Kpa, the membrane pressure difference rose slowly, and the operation was stable.

This design allows the gas-liquid kinetic energy to be completely converted into the mechanical energy of the membrane wire vibration, effectively slowing down the occurrence of membrane fouling and prolonging the membrane cleaning cycle; and the operation of the circulating pump increases the cross-flow rate on the membrane surface, enhances the power of the liquid flow, and accelerates the liquid flow rate. The rising flow rate increases the circulation of air and water, which scours the surface of the membrane filament well and prevents the concentration polarization of the inner membrane surface of the membrane module; moreover, the installation is extremely convenient, and can be directly placed in the water body to be treated without additional installation Due to the space and the existence of the shell, the chemical agent can be stored in the membrane module during chemical backwashing, reducing the amount of chemical agent and making it difficult for the chemical agent to diffuse out; effectively avoiding mechanical damage to the membrane filament.

Claims (2)

1. A gas-water mixing cleaning device for submerged hollow fiber membrane modules, comprising a fiber membrane module (1) submerged in a water tank (3), characterized in that: the cleaning device is a submerged cleaning device, using Column-type external pressure hollow fiber membrane module, the upper water outlet (11) and the lower water outlet (11') of the fiber membrane module (1) pass through the water collection pipe (4) through the pressure gauge (7) and the control valve (9) and The suction pump (17) is connected, and the air inlet (12) at the lower end of the fiber membrane module (1) passes through the aeration pipe (5) and the air compressor (18) through the control valve (10) and the pressure gauge (8). Connection, the upper side port (13) of the fiber membrane module (1) is connected with the circulating pump (16) through the circulating water pipeline (6) and the control valve (15). 2. The air-water mixing and cleaning device of the submerged hollow fiber membrane module according to claim 1, characterized in that the casing (2) of the hollow fiber membrane module (1) has a circumference of the lower end of the casing (2). A plurality of water inlets (14) are arranged on the surface.