CN117695855A - Ceramic membrane system and cleaning method - Google Patents

Abstract

The invention discloses a ceramic membrane system and a cleaning method, wherein the system comprises a back flushing water inlet pump, an ozone generator, a raw water inlet pump, a membrane pond and a water producing tank which are sequentially connected, wherein a plurality of groups of ceramic membrane components are arranged in the membrane pond, and each group of ceramic membrane components consists of even-numbered flat ceramic membranes; the ceramic membrane component is respectively connected with a back flushing water inlet pump and an ozone generator through pipelines; the water outlet of the ceramic membrane component is connected with the water production tank through a pipeline with a suction pump, so that the problems of low ceramic membrane cleaning efficiency and influence on normal production are solved.

Description

Ceramic membrane system and cleaning method

Technical field

The invention relates to a ceramic membrane system and a cleaning method, belonging to the technical field of water treatment.

Background technique

In the field of water treatment, membrane technology has been widely studied and discussed due to its efficient and clean treatment effect. Ultrafiltration membrane technology can effectively control pollutants such as particulate matter, colloids, bacteria and macromolecular organic matter in raw water, effectively ensure the biological safety of effluent water quality, and is the key to the advanced treatment process of water plants. However, membrane fouling is an important issue restricting the development of ultrafiltration membrane technology. Reversible fouling on the membrane surface can be effectively controlled through periodic hydraulic backwashing or air flushing, but there is still stubborn irreversible fouling that affects the water production efficiency of the ultrafiltration membrane.

Ceramic membrane is one of the membrane technology carriers that has developed rapidly in the world in recent years. Compared with common organic membranes, ceramic membranes have outstanding performance in terms of anti-pollution, heat resistance, chemical resistance, mechanical strength, and service life. Faced with the problem of irreversible pollution, ceramic membranes can adopt more radical cleaning methods to achieve a more significant membrane flux recovery effect, but at the same time, the cost of water production will be increased accordingly. And conventional chemical cleaning usually uses chemicals to soak for a long time. This method not only requires high concentrations of chemicals, which is not friendly to the environment, but also long-term downtime will affect the normal production of water treatment technology.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies in the prior art, provide a ceramic membrane system and a cleaning method, and solve the problem of low cleaning efficiency of the existing ceramic membrane and affecting normal production.

In order to achieve the above objects, the technical solutions adopted by the present invention are:

In a first aspect, the present invention provides a ceramic membrane system, including a backwash water inlet pump, an ozone generator, and a raw water inlet pump, a membrane tank and a water production tank connected in sequence. Several sets of ceramic membrane modules are installed in the membrane tank. Each set of ceramic membrane modules consists of an even number of flat ceramic diaphragms;

The ceramic membrane module is connected to the backwash water inlet pump and the ozone generator through pipelines respectively; the water outlet of the ceramic membrane module is connected to the water production tank through a pipeline with a suction pump.

The working pressure of the ozone generator is 0.8-1.2MPa, and the ozone concentration introduced into the ceramic membrane module is 5±0.5 mg/L. It does not require high-concentration and long-term chemical agent addition, and is environmentally friendly.

Combined with the first aspect, further, at least two groups of ceramic membrane modules are provided, and flat ceramic diaphragms in different ceramic membrane modules are arranged at intervals in the membrane tank to realize ozone online self-cleaning of ceramic membranes; a single group of ceramic membranes pass When ozone is introduced, this set of ceramic membranes achieves effective flux recovery under the action of gas-water backwashing of ozone and water.

Furthermore, the distance between each flat ceramic membrane in the membrane tank is 5 to 10 cm, and ozone micro-nano bubbles can achieve effective cleaning of ceramic membrane pollution without interfering with the filtration of the ceramic membrane.

Further, the system further includes a three-way valve having a first port, a second port and a third port, which are respectively connected to the ceramic membrane module, the ozone generator and the backwash water pump.

Further, the pipeline connecting the raw water inlet pump and the membrane tank is provided with a water inlet valve; the pipeline connecting the ceramic membrane module and the backwash water inlet pump is provided with a backwash water inlet valve, and the pipeline connected to the ozone generator is provided with a backwash water inlet valve. An air inlet valve is provided; a water production valve is provided in the pipeline where the suction pump is located; and a vent valve is provided at the bottom of the membrane tank.

Furthermore, a pressure sensor is provided on the pipeline connected to the water outlet of the ceramic membrane module, and the pressure sensor is used to monitor the transmembrane pressure difference of the ceramic membrane in real time.

In a second aspect, the present invention provides a cleaning method for a ceramic membrane system, including:

Start the raw water inlet pump and suction pump to filter the water produced by the ceramic membrane system;

Clean one group of ceramic membrane modules in sequence, and the other groups of ceramic membrane modules continue to filter the produced water;

Cleaning a set of ceramic membrane modules includes the following steps:

Stop the suction pump connected to this group of ceramic membrane modules, start the ozone generator and backwash water inlet pump, introduce ozone and backwash water into this group of ceramic membrane modules, and set the cleaning time for cleaning;

Stop the ozone generator and backwash water inlet pump, start the suction pump connected to the cleaned ceramic membrane components, restore several groups of ceramic membrane components to filter the produced water at the same time, achieve environmentally friendly and efficient online cleaning of contaminated membranes, and ensure maximum normality Production.

Compared with the prior art, the beneficial effects achieved by the present invention are:

The present invention realizes on-line ozone self-cleaning of the ceramic membrane through at least two groups of ceramic membranes being separately aerated; when a single group of ceramic membranes is introduced to ozone, the group of ceramic membranes achieves effective flux recovery under the gas-water backwashing action of ozone and water. ;

Using ozone as a cleaning agent eliminates the need for high-concentration and long-term chemical dosing, and is environmentally friendly; set the appropriate pressure to the ozone generator, and after ozone passes into the ceramic membrane, it can aerate through the tiny pores of the ceramic membrane to generate ozone micro-nano bubbles. Ozone micro-nano bubbles have high ozone mass transfer efficiency and long life in water. They can soak and clean the ozone of another set of ceramic membranes in situ, and achieve the recovery of filtration flux during the water production process;

With appropriate intervals between each flat ceramic membrane, ozone micro-nano bubbles can achieve effective ceramic membrane pollution cleaning without disturbing the ceramic membrane filtration conditions; the ceramic membrane system and cleaning method proposed by the present invention can achieve environmental friendliness of the contaminated membrane. And efficient online cleaning ensures normal production to the greatest extent.

Description of the drawings

Figure 1 is a schematic structural diagram of a ceramic membrane system provided by an embodiment of the present invention;

Figure 2 is an enlarged schematic diagram of a ceramic membrane module provided by an embodiment of the present invention;

In the picture: 1. Raw water inlet pump, 2. Membrane tank, 3. Ceramic membrane module, 31. The first set of flat ceramic diaphragms, 32. The second set of flat ceramic diaphragms, 4. Backwash inlet pump, 5. Ozone Generator, 6. First suction pump, 7. Second suction pump, 8. Water production tank, 9. Three-way valve, 10. Water inlet valve, 11. Backwash water inlet valve, 12. First air inlet Valve, 13. Second air inlet valve, 14. Vent valve, 15. First water production valve, 16. Second water production valve, 17. First pressure sensor, 18. Second pressure sensor.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings. The following examples are only used to more clearly illustrate the technical solutions of the present invention, but cannot be used to limit the scope of the present invention.

In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description. It is not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore is not to be construed as a limitation of the invention. In addition, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise clearly stated and limited, the terms "installation" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection. Ground connection; it can be direct connection, indirect connection through an intermediate medium, or internal connection between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood on a case-by-case basis.

The invention provides a ceramic membrane system, which is an ozone online self-cleaning ceramic membrane system used in water treatment processes. The ceramic membrane system includes a raw water inlet pump 1, a membrane pool 2, a ceramic membrane component 3, a backwash inlet Water pump 4, ozone generator 5, first suction pump 6, second suction pump 7 and produced water tank 8.

Among them, the raw water inlet pump 1 provides water for the membrane tank 2. A ceramic membrane module 3 is installed in the membrane tank 2. The ceramic membrane module 3 is composed of an even number of flat ceramic diaphragms, at least 2 or more.

The backwash water inlet pump 4 is connected to each flat ceramic membrane through a pipeline and is used to pump backwash water into the interior of the ceramic membrane. The ozone generator 5 is connected to each flat ceramic membrane through a pipeline and is used to pump ozone into the interior of the ceramic membrane. The first suction pump 6 and the second suction pump 7 are connected to the water outlet of the ceramic membrane through pipelines. Water is sucked out of the membrane within the membrane.

The ozone concentration introduced into the ceramic membrane module is 5±0.5mg/L. In the preferred embodiment of the present invention, the ozone dosage is 5mg/L, and the working pressure of the ozone generator 5 is 0.8-1.2MPa.

Preferably, the ceramic membrane system also includes a three-way valve 9, wherein the three-way valve 9 has a first port, a second port and a third port. The first port is connected to the ceramic membrane module 3, and the second port is connected to the ozone generator 5. , the third port is connected with the backwash water inlet pump 4.

In a preferred embodiment, the pipelines in the ceramic membrane system are equipped with various electric valves, including:

The raw water inlet pump 1 pipeline is equipped with a water inlet valve 10, the backwash water inlet pump 4 pipeline is installed with a backwash water inlet valve 11, and the ozone generator 5 pipeline is equipped with a first air inlet valve 12 and a second air inlet valve 13. The first The first water production valve 15 and the second water production valve 16 are respectively installed in the pipelines where the suction pump 6 and the second suction pump 7 are located; and a vent valve 14 is installed at the bottom of the membrane tank 2 .

Furthermore, in this embodiment, the ceramic membrane module 3 is provided with a first group of ceramic membrane modules and a second group of ceramic membrane modules, which are connected to the first suction pump 6 and the second suction pump 7 respectively. Two first group flat ceramic diaphragms 31 in the first group of ceramic membrane modules and two second group flat ceramic diaphragms 32 in the second group of ceramic membrane modules are arranged at intervals in the membrane tank 2. The first group of ceramic membranes 31 and the second group of ceramic membranes 32 are arranged at intervals in the membrane tank 2, as shown in Figure 2.

The invention also provides a method for online self-cleaning of ceramic membranes with ozone, using the aforementioned ceramic membrane system for online cleaning, which specifically includes the following steps:

S1. Start the raw water inlet pump 1, the first suction pump 6 and the second suction pump 7, open the water inlet valve 10, the first water production valve 15 and the second water production valve 16. The raw water is pumped under the action of the suction pump. Filtration of water is achieved through the ceramic membrane module 3;

S2. Set the first stage filtration time, preferably after 30 minutes, the first suction pump 6 stops, the first water production valve 15 closes, the ozone generator 5 and the backwash water inlet pump 4 start, the first air inlet valve 12 and The backwash water inlet valve 11 is opened, and ozone and backwash water are introduced into the first group of ceramic membranes 31 . When the first group of ceramic membranes 31 is introduced into ozone aeration conditions, the second group of ceramic membranes 32 continues to produce water, realizing ozone online self-cleaning of the ceramic membrane system;

S3. Set the first stage ozone cleaning time. After preferably 1 minute, the first group of ceramic membranes 31 will stop cleaning, the ozone generator 5 and the backwash water inlet pump 4 will stop, and the first air inlet valve 12 and the backwash water inlet valve 11 will stop. Close, the first water production valve 15 opens, the first suction pump 6 is started, and the two sets of ceramic membranes resume water production at the same time;

S4. Set the second stage filtration time, preferably after 30 minutes, the second suction pump 7 stops, the second water production valve 16 closes, the ozone generator 5 and the backwash water inlet pump 4 start, the second air inlet valve 13 and The backwash water inlet valve 11 is opened, and ozone and backwash water are introduced into the second group of ceramic membranes 32 . Under the ozone aeration conditions introduced by the second group of ceramic membranes 32, the first group of ceramic membranes 31 continues to produce water;

S5. After setting the second stage ozone cleaning time, preferably 1 minute, the second group of ceramic membranes 32 stop cleaning, the ozone generator 5 and the backwash water inlet pump 4 stop, the second air inlet valve 13 and the backwash water inlet valve 11 is closed, the second water production valve 16 is opened, the second suction pump 7 is started, the two sets of ceramic membranes are restored to produce water at the same time, and the next operation cycle is entered.

The implementation and cleaning effect of the present invention will be further explained below with reference to specific examples.

Example 1:

In this example, the ozone online self-cleaning ceramic membrane system is applied to the field of drinking water treatment. The turbidity of the raw water is 15NTU. The ceramic membrane filtration flux is set to 60LMH, the backwash flux is set to 100LMH, and the ozone dosage is set to 5mg/ L, the working pressure of the ozone generator is set to 0.8MPa, and the distance between each ceramic membrane is 5cm. Cleaning efficiency = (transmembrane pressure difference after filtration - transmembrane pressure difference after cleaning) / (transmembrane pressure difference after filtration - initial transmembrane pressure difference) The specific effects are shown in Table 1.

Table 1: Ozone online self-cleaning ceramic membrane test results

Example 2:

The ozone online self-cleaning ceramic membrane system is applied to the field of drinking water treatment. The raw water turbidity is 30NTU. The ceramic membrane filtration flux is set to 50LMH, the backwash flux is set to 100LMH, and the ozone dosage is set to 5mg/L. The working pressure of the generator is set to 1.0MPa, and the distance between each ceramic membrane is 7.5cm. Cleaning efficiency = (transmembrane pressure difference after filtration - transmembrane pressure difference after cleaning)/(transmembrane pressure difference after filtration - initial transmembrane pressure difference). The specific effects are shown in Table 2.

Table 2: Ozone online self-cleaning ceramic membrane test results

Embodiment three:

The ozone online self-cleaning ceramic membrane system is applied to the field of drinking water treatment. The raw water turbidity is 50NTU. The ceramic membrane filtration flux is set to 40LMH, the backwash flux is set to 100LMH, and the ozone dosage is set to 5mg/L. The working pressure of the generator is set to 1.2MPa, and the distance between each ceramic membrane is 10cm. Cleaning efficiency = (transmembrane pressure difference after filtration - transmembrane pressure difference after cleaning)/(transmembrane pressure difference after filtration - initial transmembrane pressure difference). The specific effects are shown in Table 3.

Table 3 Ozone online self-cleaning ceramic membrane test results

It can be seen from the test results of the above different embodiments that in the face of raw water with different turbidity levels, under the ozone online self-cleaning of the present invention, the ceramic membrane system can operate stably for a long time, and the recovery rate of the transmembrane pressure difference during the cycle is more than 95%.

The invention involves two different cleaning methods, which are as follows:

First, the ceramic membrane performs direct ozone combined with hydraulic backwashing during backwashing;

Secondly, when two adjacent ceramic membranes are backwashed, ozone is aerated through the ceramic membrane to generate ozone micro-nano bubbles, so that the ceramic membranes in normal production can be immersed and cleaned online with ozone micro-nano bubbles.

In the embodiment of this application, when the first stage of cleaning is completed, the cleaning efficiency of the first group of ceramic membranes reflects the cleaning effect of the first direct ozone combined with hydraulic backwash; the cleaning efficiency of the second group of ceramic membranes reflects the cleaning effect of the second type of ozone. Cleaning effect of micro-nano bubble online immersion cleaning.

Through the two different cleaning methods involved in the invention, the cleaning efficiency of the ceramic membrane of direct ozone combined with hydraulic backwash can reach more than 99%, while the online immersion cleaning efficiency of ozone micro-nano bubbles can reach more than 95%. The overall cleaning effect good.

The above are only preferred embodiments of the present invention. It should be noted that those of ordinary skill in the art can also make several improvements and modifications without departing from the technical principles of the present invention. These improvements and modifications It should also be regarded as the protection scope of the present invention.

Claims (7)

1. A ceramic membrane system, characterized in that it includes a backwash water inlet pump, an ozone generator, and a raw water inlet pump, a membrane tank and a water production tank connected in sequence. Several groups of ceramic membrane components are installed in the membrane tank, each The ceramic membrane module is composed of an even number of flat ceramic diaphragms; The ceramic membrane module is connected to the backwash water inlet pump and the ozone generator through pipelines respectively; the water outlet of the ceramic membrane module is connected to the water production tank through a pipeline with a suction pump. The working pressure of the ozone generator is 0.8-1.2MPa, and the ozone concentration introduced into the ceramic membrane module is 5±0.5mg/L. 2. The ceramic membrane system according to claim 1, characterized in that there are at least two groups of ceramic membrane modules, and flat ceramic diaphragms in different ceramic membrane modules are arranged at intervals in the membrane tank. 3. The ceramic membrane system according to claim 2, characterized in that the spacing between each flat ceramic membrane in the membrane tank is 5 to 10 cm. 4. The ceramic membrane system according to claim 1, characterized in that the system further includes a three-way valve, the three-way valve has a first port, a second port and a third port, respectively connected with the ceramic membrane component, The ozone generator and the backwash water inlet pump are connected. 5. The ceramic membrane system according to claim 1, characterized in that the pipeline connecting the raw water inlet pump and the membrane tank is provided with a water inlet valve; the pipeline connecting the ceramic membrane module and the backwash water inlet pump is provided with a water inlet valve. Backwash water inlet valve, the pipeline connected to the ozone generator is provided with an air inlet valve; the pipeline where the suction pump is located is provided with a water production valve; the bottom of the membrane tank is provided with a vent valve. 6. The ceramic membrane system according to claim 1, characterized in that a pressure sensor is provided on the pipeline connected to the water outlet of the ceramic membrane module, and the pressure sensor is used to monitor the transmembrane pressure difference of the ceramic membrane in real time. 7. The cleaning method of the ceramic membrane system according to any one of claims 1-6, characterized in that it includes: Start the raw water inlet pump and suction pump to filter the water produced by the ceramic membrane system; Clean one group of ceramic membrane modules in sequence, and the other groups of ceramic membrane modules continue to filter the produced water; Cleaning a set of ceramic membrane modules includes the following steps: Stop the suction pump connected to this group of ceramic membrane modules, start the ozone generator and backwash water inlet pump, introduce ozone and backwash water into this group of ceramic membrane modules, and set the cleaning time for cleaning; Stop the ozone generator and backwash water inlet pump, start the suction pump connected to the cleaned ceramic membrane components, and restore several groups of ceramic membrane components to simultaneously filter the produced water.