The core element of a membrane filter is the membrane, which is a membrane covered with even smaller pores on a microporous support layer (support body). There are many different materials used to make the membrane, including organic membranes (such as polysulfone hollow fibre membranes) and inorganic membranes.
The structure of the membrane as a filtration element is characterised by a very thin layer, so its filtration mechanism is mainly a sieving effect, with little adsorption effect. As a result, membrane filters have a high filtration accuracy, stable particle size control and easy backwashing to restore performance. However, if the water contains oil, it is easily clogged and not easily backwashed. Many researchers at home and abroad have looked to ceramic membranes to treat produced water based on the hydrophilic nature of ceramic materials, but after research, it is generally agreed that membrane contamination is still a difficult problem to solve. Membrane contamination is a very complex issue, but one thing is certain – the presence of large amounts of organic matter in the contaminants is certain, although the focus is often on the membrane itself and less on the support layer. Analysis of the adsorption mechanism in conjunction with the pore characteristics of the membrane and support layers explains why membrane filtration is less prone to clogging for clear water and more prone to clogging for oily wastewater. For solids in suspension in general, particles larger than the membrane pores are retained (sieved) on the membrane surface, while particles smaller than the membrane pores pass through the membrane pores and cannot be adsorbed due to the thinness of the membrane as a filtration layer. This has only a sieving effect, so it is easy to backwash and remove. For oil in water, on the other hand, due to the instability of the oil droplets, droplets larger than the membrane pores are not necessarily sieved out as they may split into droplets smaller than the membrane pores and pass through the membrane pores, and although they can pass through the membrane itself, they can agglomerate into large droplets in the support layer and be adsorbed by the micro-pores of the support layer and cannot be desorbed. As a result, oily effluent can clog the membrane filter and backwashing is difficult. This filter is therefore suitable for the filtration of clear water in low permeability formations, but not for the filtration of oil-bearing produced water.
It has the advantages of high filtration accuracy, fast filtration speed, less adsorption, no media shedding, no leakage, acid and alkali corrosion resistance, easy operation, etc. It can remove bacteria and particles from water and pharmaceutical solution in injection water, and can be backflushed when cleaning.
Membrane technology is a high technology of high separation, concentration, purification and purification which has been rapidly developed in recent years, and new membrane equipment has been developed, researched and applied continuously in China, and many aspects are close to the advanced level of similar products abroad. As we all know, the current filter operation has entered the era of membrane filtration, with the deepening of people’s understanding of filtration membrane, membrane filtration will certainly be widely used in most people’s filtration operation. Because, it can be used both as fine filtration equipment alone and as other purification devices (such as ion resin exchange, electrodialysis, reverse osmosis and ultrafiltration, etc.) to pre-treatment equipment.
Membrane filtration is popular among users for its high precision, wide range of applications, backflushability, as well as compact structure and simple operation.
Structure Description Editor Podcast
1, the cartridge is a folded cartridge microporous membrane cartridge, the diameter of the cartridge shell is 2.7 feet (i.e. 69mm), the length of the cartridge with 10, 20, 30 and 40 feet (i.e.: 250, 500, 750 and 1000mm) four, and the filter shell sealing method is divided into insert type (also divided into 222 seat, 226 seat) and flat nozzle type two. The breakdown is as follows
a. The insertion type cartridge includes 222 and 226 seats, which is the international standard number of the interface between the cartridge and the cartridge insert plate. 222 seats are “O” shaped sockets and 226 seats are “O” shaped interfaces with a pair of lugs on them, which can be stuck into the groove on the bearing insert plate of the filter shell to fix the upper end of the filter when it is installed.
b. The upper and lower ends of the flat-mouthed cartridge are both flat, and the link between the cartridge and the filter housing insert plate is fixed with a flat sealing ring.
Specially designed and manufactured cartridges with special specifications and applications (e.g. cartridges for household water purifiers, etc.) are also available according to the needs of users. Long-term supply of “O” shaped seals and flat seals.
The microporous membrane cartridge filter consists of a microporous film cartridge and a stainless steel housing, as well as the necessary stainless steel piping and valves.
The lower part of the filter has an insert plate for inserting the cartridge, and there are holes on the plate for inserting the cartridge. According to the different flow rates handled by users, the filter has a single core with 3 cores, 5 cores, up to dozens of cartridges. At the same time, for the convenience of cartridge loading and unloading, the shell is divided into two parts, which are connected with quick-fit bolts.
Instructions for use Editorial Podcast
The filtration model is: MFa-b
MF-is the code of “microporous membrane filter”; a-is the code of filter cartridge length; b-the code of the number of cartridges set in the filter.
For example, if the model number is MF20-3, it means that the cartridge length is 20 inches and the filter is equipped with 3 cartridges.
The filter parameters include: Specification, membrane material, operating pressure, and pressure.
Example: Specification: 0.2um, 3T/h or 3m3 means 3 tons of liquid flow per hour, or 3 cubic metres of filtered air per minute.
Membrane material: PP indicates polypropylene material (membrane material code between the preamble a text) Operating pressure: ≦0.3mpa indicates that the working pressure can not be greater than 3kg pressure.
Preparation before installation
a. Cleaning of the cartridge
① The newly purchased cartridge must be sterilized with disinfection solution or steam before installation, generally the pre-filter does not need to be sterilized, and the sterilization is mainly used for 0.4-0.45um cartridge.
When using disinfection sterilization, it should be configured into a certain concentration of disinfection solution according to the product instructions, for example (when using Vanguard disinfectant, it can be configured into a concentration of 100-150 ppm disinfection solution for use, etc.), and then the cartridge is squarely immersed in the disinfection solution for 1-2 hours, and then rinsed with water after 2 until there is no residual disinfection solution.
When steam is used, saturated steam at 0.1-0.15mpa pressure can generally be used to sterilise for 20-30 minutes. However, care should be taken that the steam valve should be opened slowly to avoid a sudden rush of steam into and damage to the cartridge.
When purchasing cartridges, note that if steam sterilization is required frequently, it must be explained to the supplier in order to provide cartridges that are resistant to steam sterilization.
② For newly purchased acetate cartridges, sterilization should only be carried out with disinfection solution, but not with steam.
b. Cleaning of stainless steel filter housings
① Newly purchased stainless steel filter housings, as well as the pipes and valves before and after, must be thoroughly cleaned with detergent from the oil and dirt adhering to them during processing, membrane filter press as well as from the sand and dirt adhering to them during transportation;
② Soak in a disinfectant solution to disinfect and sterilise;
③ Rinse with water until no residual disinfection solution remains.
Preparation before use
a. After the cartridge and housing have been thoroughly cleaned and sterilised, the filter can be installed. Firstly, after applying clean filtering liquid as lubricant on the “O” ring of the Lixin, then insert the filter cartridge carefully and vertically into the lower bearing plate of the filter, if the pump uses the 226 interface, the interface should be inserted into the chassis with both ears, and after the filter “O” has been changed into the socket, the filter cartridge should be screwed in clockwise so that the double ears are inserted into the chassis. Turn in clockwise so that the double ears are stuck into the empty hole slot of the chassis. After catching the industry and tightening the bolt seal.
b. After the filter system has been flushed, the entire filter system must be thoroughly flushed with water.
c. After the entire filter system has been rinsed clean, the filtering operation can be carried out.
Operation in production
a. Filtering operation
Open the exhaust valve and slowly open the inlet valve to introduce the liquid to be filtered. When there is liquid outflow from the exhaust valve, immediately close the exhaust valve and slowly open the outlet valve.
At the early stage of filtration, as the filter element is still clean and the filtration speed is fast, the internal pressure of the filter is generally maintained at 0.05-0.1mpa. With the passage of time, in order to maintain the appropriate filtration rate, the pressure inside the vessel can be gradually adjusted upwards, but the maximum pressure inside the filter cannot exceed the maximum operating pressure allowed for different material cartridges.
When the internal pressure is already high and the filtration rate is slowed down more, the filtration operation should be stopped and the filter should be clarified.
b. Backwashing of the filter cartridge
① For mineral water and fine filtration in water treatment, backwashing can be selected for cleaning for backwashing, and then put back into production after backwashing with clean water from terminal filtration.
② For the filtration of fermented liquids and sugary liquids such as beer and beverages, it is recommended to use clean oil-free compressed air back-blowing after pre-treatment, then clean water backflushing, and then clean water backflushing by terminal filtration before putting into production again.
③ When the filter cartridge has been adapted for a longer period of time and the filtration speed is still not satisfactory after backflushing with the above method, the filter cartridge can be removed and soaked in NaOH solution with a concentration of 2-4% for 4-8 hours and then rinsed with clean water filtered by the terminal until there is no residue. Rinse with clean water until there is no residual detergent, then install.
④ After installation, the filtration system should be fully disinfected with steam at a pressure no higher than 0.15mpa for 20 minutes. After disinfection, all fastening bolts in the system should be checked for looseness and re-fastened.
⑤ Before disinfection with steam, steam pipes must be drained of steam condensate, and then slowly open the steam valve for disinfection.
(6) The gas to be filtered must first be dehumidified so that its relative humidity is reduced to ≦70%; if the compressed air is filtered, the compressed air should also be de-oiled before it is filtered. During operation, all inlet and outlet gas valves should be opened slowly.
⑦ When filtering CO2 vapour removed from the fermenter, the filter should be installed on the fermentation operation platform to prevent backflow of fermentation broth.
⑧ After the filter has been in operation for some time, the pressure will gradually increase. When the differential pressure reaches 0.015mpa, the operation should be stopped and the filter cartridge should be cleaned; the cleaning method can be back-blown with clean compressed air, and steam disinfection cleaning, etc. After the cleaning is completed, install it again to continue the operation.