What are the centrifuge basics?

Petrochemical production processes usually use gases or liquids, and therefore rarely encounter solid-liquid separation. But in some other chemical production process, especially fine chemicals, pharmaceutical chemicals and pesticide chemicals, often produce solid particles, solid products and solid intermediates of the process.

Because solids are not as fluid as moxibustion better fluidity, so the solid particles in the transport and separation process is very different from the liquid. Solids cannot be separated by extraction or distillation. How to effectively separate the solids produced in the liquid is one of the main technical difficulties faced by the production process of the solids mentioned above.

Centrifuge is a kind of equipment for separating materials, belonging to the category of dynamic equipment, which can separate the light and heavy components by centrifugal force with the help of different density relationship of materials.

Centrifuges are usually used for the separation of solid materials in the liquid, of course, with the development of technology, there are now also from two different liquid materials with different densities of liquid separation centrifuge.

The cyclone dust collector we see is also a device with a similar principle to the centrifuge, except that it has no mechanical moving parts and is a static device. It separates gas-liquid or gas-solid by means of the centrifugal force generated by the flow of air in it.

The most common centrifuges are liquid-solid centrifuges, which are basically divided into filter centrifuges and sedimentation centrifuges.

Filtration centrifuges can be divided into three-legged centrifuges, top-suspended centrifuges, horizontal scraper discharge centrifuges (including siphon scraper discharge centrifuges), horizontal piston centrifuges, centrifugal force discharge centrifuges, and spiral discharge filtration centrifuges and so on.

Sedimentation centrifuge can be divided into spiral discharge sedimentation centrifuge, disc separator, tube separator and chamber separator.

With the gradual high demand for automation, a large number of hazardous chemical production processes need to be automated and continuous transformation, continuous centrifuges are more and more attention.

Currently, continuous centrifuges are commonly used in automated systems with continuous feed and continuous discharge. Unloading is usually powered by centrifugal force or other mechanical unloading devices, which are usually screw unloading devices.

Centrifuge selection should take into account the centrifugal separation of the liquid characteristics, such as the content of solids in the liquid, the diameter of the solid particles and the density difference between the solid and the liquid. If there is a certain difference between the density of solids and liquids, it is necessary to choose a special centrifuge with a high centrifugal separation factor to meet the separation requirements.

Centrifugal separation factor, also known as centrifugal separation coefficient, is a very important performance parameter of centrifuges, which refers to the centrifugal acceleration acting on the material to be separated, equal to a multiple of the acceleration of gravity.

The larger the centrifugal separation factor, the better the separation effect, and vice versa, the weaker the separation effect. In the case of the same drum diameter, the larger the centrifugal separation factor, the higher the rotational speed and the stronger the centrifugal force, and conversely, the lower the rotational speed and the smaller the centrifugal force.

For the same rotational speed, the larger the diameter of the drum, the higher the centrifugal separation factor, and conversely, the lower the centrifugal separation factor.

Centrifuges used to separate liquids and solids are usually used for coarse separations in which the solids are usually separated with a certain amount of liquid. The liquid content of solids is usually about 10 per cent. Depending on the nature of the liquids and solids, the liquid content range fluctuates. In some special cases, the liquid content can even reach 50 per cent.

The centrifugal efficiency of centrifuges has a certain upper limit, so that the liquids separated by the centrifuge also contain a certain amount of solids. This solids content is usually related to the particle size of the solids and the density difference between the solids and the liquid, as well as to the operating parameters of the centrifuge and its efficiency.

Generally, the solid content in the liquid obtained by centrifugation should be less than 0.5 per cent. But for the above mentioned as a result of the density difference between liquid and solid is small, solid particle size is small, the viscosity of the liquid is high, solid and liquid wettability is too good, the effect of strong and other factors, some of the liquid phase in the solid content can even reach 50%.

Centrifuge in the process of operation, due to the violent movement will produce a certain crushing effect, so for the crystal particle size requirements of the process, should choose other suitable separation equipment. The use of centrifuges should be avoided to avoid crystal breakage during the separation process, which may affect the product quality.