What are the main features of membrane separation method, and what are the membrane separation techn

The main characteristics of the membrane separation method are no phase change, low energy consumption, the scale of the device can be large or small according to the requirements of the processing capacity, and the equipment is simple, the operation is convenient and safe, the start is fast, the operation reliability is high, the environment is not polluted, the investment is low, and the use is wide.

Separation and concentration at room temperature and low pressure result in low energy consumption, resulting in low operating costs.

The equipment is small in size and simple in structure, so the investment cost is low.

The membrane separation process is simply pressurized to convey liquid, the process flow is simple, and it is easy to operate and manage.

As a filter medium, the membrane is a homogeneous continuum made of polymer materials, which is filtered by pure physical methods, and the substances do not undergo qualitative changes in the separation process (that is, they do not affect the molecular structure of the materials).

Polymer separation membrane is a semi-permeable thin layer material made of polymer materials with selective permeability function. There are mainly polyamines, polyimines, polysulfones, polyvinylic acids, propylene derivatives, polymers and cellulose. However, most polymer materials have the disadvantages of PO2 and O2 N2 restricting each other, and are not resistant to high temperature and easy to corrode.

Polysulfone is a membrane material with excellent mechanical properties, good heat resistance, resistance to microbial degradation, and low and easy to obtain. Because the membrane made of polysulfone has the characteristics of thin film, high porosity of the inner layer and regular micropores, it is often used as the basic material of gas separation membrane.

1. There is no phase change in the membrane separation process, and the energy consumption is lower than that of the separation method with phase change and other separation methods.

2. The membrane separation process is carried out at room temperature, so it is especially suitable for the separation, classification, concentration and enrichment of heat-sensitive substances, such as juice, enzymes, drugs, etc.

3. Membrane separation technology is not only suitable for a wide range of separation of organic and inorganic substances, from viruses, bacteria to particles, but also for the separation of many special solution systems, such as the separation of macromolecules and inorganic salts in the solution, the separation of some azeotropes or near-boiling point substances, etc.

4. Because pressure is only used as the driving force of membrane separation, the separation device is simple, easy to operate, easy to control and maintain.

Membrane separation technologies mainly include the following: pervaporation, microfiltration, ultrafiltration, nanofiltration, and reverse osmosis.

1. Pervaporation - Pervaporation - Pervaporation is also known as pervaporation evaporation, which refers to a membrane separation method in which the components pass through the membrane and evaporate at different rates under the action of the vapor partial pressure difference of the components on both sides of the membrane, so as to achieve the purpose of separation. The organic pervaporation membrane uses the adsorption-dissolution mechanism of the membrane layer to the components, and the molecular sieve pervaporation membrane uses the adsorption-diffusion and molecular sieve mechanism of the membrane layer on the components. Applications include dehydration of organic solvents, removal of organic matter from aqueous solutions, and separation of organic matter from organic matter.

2. Microfiltration - often used in food and medicine disinfection, purification of liquids in semiconductor production industry, biotechnology, wastewater treatment, etc.

3. Ultrafiltration - commonly used in milk skimming, protein pre-concentration, juice clarification, fermentation broth treatment, discharge liquid treatment, etc.

4. Nanofiltration - can be used to remove oligosaccharides, dyes, multivalent ions, etc.

5. Reverse osmosis - it can be used to treat municipal wastewater, industrial wastewater, seawater and brackish water desalination, groundwater and surface water treatment.

Membrane separation technology: Mixtures of molecules of different particle sizes are selectively separated through semi-permeable membranes.

The main characteristics of the membrane separation method are no phase change, low energy consumption, the scale of the device can be large or small according to the requirements of the processing capacity, and the equipment is simple, the operation is convenient and safe, the start is fast, the operation reliability is high, the environment is not polluted, the investment is low, and the use is wide.

The advantages of the membrane separation process are as follows:

1. It is carried out at room temperature, and the loss of active ingredients is very small, especially suitable for heat-sensitive abrasive substances;

2. There is no phase change, the original flavor is maintained, only electric energy is required, and the energy consumption is very low;

3. No vertical and hidden chemical changes, typical physical separation process, no chemical reagents and additives, and the product is not polluted;

4. Good selectivity, can separate substances at the molecular level, and has excellent performance that cannot be replaced by universal filter media;

5. Strong adaptability, the processing scale can be large or small, continuous or intermittent, the process is simple, the operation is convenient, and it is easy to automate.

Enzyme preparations and protein products.

Amino acids, peptides, antibiotics.

Plant raw materials (flavonoids, pigments, etc.).

Bio-fermentation preparations.

Large infusion to remove the heat source.

Bio-algae products.

Heparin sodium, chondroitin sulfate, biopolysaccharides.

Oligosaccharides, oligosaccharides, monosaccharides.

Organic acids such as citric acid, malic acid, etc.

Fruit and vegetable juices. Brewed products (alcohol, vinegar, etc.).

Dairy product. Medical sterile nonpyrogen water equipment.

Industrial separation, concentration, purification.

Industrial wastewater treatment, electrophoretic paint, electroplating oily wastewater treatment.

Wright. Ryder There is a thin layer of condensed phase material between the phases of a fluid, which separates the fluid phase into two parts, and this thin layer of substance is called a membrane.

The membrane itself is a homogeneous one-phase or a complex composed of more than two phases of condensate.

Fluid phase substances separated by membranes Figure 1 Schematic diagram of membrane separation process Be it a liquid or a gas.

The thickness of the membrane should be below, otherwise it cannot be called a membrane. There is one basic requirement for different kinds of membranes:

1) Pressure-resistant: the membrane pore size is small, and a higher pressure must be applied to maintain a high flux, and the pressure range of the general mold operation is higher, and the pressure of the reverse osmosis membrane is higher, about 1 10MPa

2) High temperature resistance: the temperature increase brought by high flux and the need for cleaning.

3) Acid and alkali resistance: prevent hydrolysis during separation and cleaning; (4) Chemical compatibility: maintain the stability of the membrane;

5) Biocompatibility: prevent the denaturation of biological macromolecules; (6) Low cost. Classification of membranes.

According to pore size: microfiltration membrane, ultrafiltration membrane, reverse osmosis membrane, nanofiltration membrane According to membrane structure: symmetrical membrane, asymmetric membrane, composite membrane.

According to the material: organic polymer (natural polymer material film, synthetic polymer material film) film, inorganic material film.

a variety of membrane materials.

1) Natural polymer material film.

It is mainly a derivative of cellulose, including acetate, nitrate and regenerated cellulose. Among them, acetate fiber membrane has strong salt interception ability, and is often used as reverse osmosis membrane, and can also be used as microfiltration membrane and ultrafiltration membrane. The maximum temperature and pH range of acetate membrane are limited, and the general use temperature is lower than 45 50 and pH 3 8.

Regenerated cellulose is used to make dialysis membranes and microfiltration membranes.

1. Microfiltration membrane separation equipment.

In view of the separation characteristics of microporous membranes, the application scope of microporous membranes is mainly to intercept particles, bacteria and other pollutants from the gas phase and liquid phase to achieve the purpose of purification, separation and concentration.

The specific fields involved are: pharmaceutical industry, food industry (gelatin, wine, liquor, fruit juice, milk, etc.), high-purity water, municipal sewage, industrial wastewater, drinking water, biotechnology, biological fermentation, etc.

2. Ultrafiltration membrane separation equipment.

Early industrial ultrafiltration was used in wastewater and wastewater treatment. Over the past 30 years, with the development of ultrafiltration technology, ultrafiltration technology has been involved in many fields such as food processing, beverage industry, pharmaceutical industry, biological preparations, traditional Chinese medicine preparations, clinical medicine, printing and dyeing wastewater, food industry wastewater treatment, resource development, environmental engineering and so on.

3. Nanofiltration membrane separation equipment.

The main application fields of nanofiltration include: food industry, plant deep processing, beverage industry, agricultural products deep processing, biomedicine, biological fermentation, fine chemicals, environmental protection industry ......

4. Reverse osmosis membrane separation equipment.

Due to the advanced, efficient and energy-saving characteristics of reverse osmosis separation technology, it has been widely used in various sectors of the national economy, mainly used in water treatment and concentration of heat-sensitive substances, and the main application fields include the following: food industry, milk industry, beverage industry, plant (agricultural products) deep processing, biomedicine, biological fermentation, preparation of drinking water, pure water, ultrapure water, seawater, brackish water desalination, electricity, electronics, semiconductor industry water, pharmaceutical industry process water, preparation water, water for injection, Sterile and non-pyrogen-free pure water, process water, boiler water, washing water and cooling water for food and beverage industry, chemical industry and other industries.

5. Miscellaneous. In addition to the above four commonly used membrane separation processes, there are also dialysis, controlled release, membrane sensors, membrane gas separation, etc.

The most important means in the science of separation: Suihui membrane separation technology guesses hail.

Membrane separation equipment is a large-scale mechanical equipment manufactured in the production plant in accordance with the technical parameters of membrane separation by using membrane separation technology.

Membrane separation technology: the mixture of slag with different particle diameters and friends of Mae Hongzi is selectively separated through a semi-permeable membrane.

The types of membrane separation technologies include: microfiltration (MF), ultrafiltration (UF), nanofiltration (UF), reverse osmosis (RO), membrane bioreactor (MBR), membrane integration technology, etc.

Membrane separation technology is widely used in textile, electric power, machinery, fermentation, food, pharmaceutical and chemical industry, biology, environmental protection, pesticide chemical industry, metallurgy, energy, petroleum, water treatment, electronics, bionic and other fields, while improving separation efficiency, energy consumption is greatly reduced.