Views: 5 Author: Site Editor Publish Time: 2022-07-27 Origin: Site
The classification of inorganic ceramic membranes
There are many kinds of inorganic ceramic membranes, which can usually be classified according to membrane pore size, membrane material and membrane configuration.
① The classification according to the pore size of inorganic ceramic membrane
The pore size of inorganic ceramic membrane is generally in the micron level and below. According to the different filtration pore size (or the size of retained molecular weight), inorganic ceramic membrane can be divided into microfiltration membrane, ultrafiltration membrane and nanofiltration membrane.
At present, inorganic ceramic membranes that have been industrialized are mainly microfiltration ceramic membranes and ultrafiltration ceramic membranes. Nanofiltration ceramic membranes with smaller pore size range and higher separation accuracy are still in the stage of large-scale preparation technology research in China.
② The classification according to the material of inorganic ceramic membrane
The material of inorganic ceramic membrane determines the physical and chemical properties of the membrane, and then determines the main performance indicators of the ceramic membrane, such as hydrophilicity, anti pollution, high temperature resistance, acid and alkaline resistance, thermal stability and so on. According to the different materials for preparing inorganic ceramic membranes, they can be mainly divided into alumina (Al2O3), zirconia (ZrO2), titanium oxide (TiO2) and silicon oxide (SiO2) ceramic membranes.
③ The classification according to the configuration of inorganic ceramic membrane
The configuration of inorganic ceramic membrane is related to its manufacturing process, which is usually divided into chip membrane, plate membrane and tubular membrane. Among them, multi-channel tubular membrane has become the main variety in the enterprise market because of its larger film area per unit volume, high mechanical strength of the pipe body and simple installation, which is suitable for large-scale industrial applications. Single (root) membrane tube is called membrane element. The commercialized inorganic ceramic membrane element can be further divided into various configurations according to its tube length, number of channels, diameter of pipe diameter and other parameters.
The technical advantages of inorganic ceramic membrane
① Good thermal shock resistance and high temperature resistance
Under normal conditions, ceramic membrane components and membrane devices can be used stably in the working environment below 800 ℃, so ceramic membrane is especially suitable for high temperature and high viscosity fluids, and steam disinfection can be carried out for some liquids that are not suitable for chemical cleaning.
② Excellent chemical stability
It is resistant to the erosion of organic solvents and has strong anti microbial degradation ability. When dealing with strong acid and alkali materials, excellent chemical stability is particularly important. Ceramic membrane cleaning can directly use hot alkali or acid, and can be used stably in such high temperature environment.
③ Good mechanical properties
Generally, the ceramic film can withstand pressure of more than 3Mpa, will not deform under high pressure, and is resistant to high-speed scouring and wear, which is convenient for recoil and cleaning.
④ Excellent duct structure
Inorganic ceramic membrane modules are generally composed of multiple or multiple single channel or multi-channel single piece membranes. Compared with organic polymer membranes, this structure is not easy to cause membrane blockage and is very easy to clean. Therefore, the ceramic membrane can obtain a higher concentration ratio when purifying or concentrating; The flow rate of ceramic membrane decreases slowly, and the flow rate will not be too low when the blockage degree is high; Ceramic membrane cleaning is simple, efficient, low-cost, and there is less deposit in the membrane module, which is especially suitable for the food and pharmaceutical industries.
⑤ Controllable pore microstructure
Through the selection of raw materials or the control of pretreatment process, molding process, sintering and other parameters, the microstructure of inorganic ceramic membrane can be purposefully controlled.
⑥ Long service life of ceramic membrane
In the field of industrial separation, the service life of ceramic membrane is generally 3-5 years or even longer, so the later replacement and maintenance cost is greatly reduced compared with that of organic membrane.
⑦ Less energy consumption
Ceramic membranes are generally pressure driven separation at room temperature, and do not need to provide other energy or chemical reagents.
⑧ No pollution to the environment
The preparation process and separation process of ceramic membrane materials do not produce secondary pollution to the environment.
In addition, the ceramic membrane also has many advantages, such as high separation efficiency, stable effect, acid and alkali resistance, organic solvent resistance, bacteria resistance, high temperature resistance, high mechanical strength, good regeneration performance, simple separation process, simple operation and maintenance, etc.