GN New Type 3 Phase Decanter Centrifuge for Oil and Water Separation

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3 phase decanter centrifuge is a widely used equipment for separation of solids, heavy liquid and light liquid with specific gravity difference. In many of morden industries like oily sludge treatment, slaughterhouse wastewater treatment, kitchen waste treatment, oil clarifying, fish products, wheat starch production, etc. GN Separation is one of manufacturers who provide 3 phase decanter centrifuge with based on more than ten years of practical experience.

GN 3 Phase Decanter Centrifuge

3 Phase decanter centrifuge

In the Separation Industry, 3 phase separation technology are more and more popular. Especially the industry required high efficiency 3 phase decanter centrifuges for oil and water separation. GN 3 phase decanter centrifuge is developed by GN Company based on more than ten years of practical experience in the separation field. Its main function is to solve the separation of solid phase and two immiscible liquids at one time based on the specific gravity difference. Relying on mature design and high-quality raw material selection, GN 3 phase decanter centrifuge can meet the requirements of 24-hour continuous and stable operation.

1. Brief of 3 Phase Decanter Centrifuge

1.1 Working principle of 3 Phase Decanter Centrifuge
GN 3 phase decanter centrifuge is composed of 7 major mechanisms, including feeding component, underframe component, bowl component, screw component, differential gear box, drive component and collection box component. The materials to be separated are sent into the feeding component by the conveying system, and then flow into the inner cavity of the bowl, rotating synchronously with the bowl. Due to different specific gravity, the centrifugal force is different, heavy solid particles will get the largest centrifugal force, followed by heavy phase liquids (such as water), and the smallest for light phase liquids (such as oil). In this way, a concentric solid layer and two liquid layers are formed from the outside to the inside according to the centrifugal force. Under the relative motion of the bowl and the screw, the solid deposited on the inner wall of the bowl is pushed to the solid outlet direction of the machine by the screw, further dried under the extrusion, and then discharged; The liquid phase flows to the outlet of the liquid phase at the other end of the machine and overflows at different outlets, realizing three-phase separation of solid phase, heavy liquid phase and light liquid phase. GN three-phase decanter centrifuge adopts centripetal pump technology to adjust the position of neutral layer of heavy liquid phase and light liquid phase, and can select the appropriate position of liquid discharge layer according to different liquid phase proportion. At the same time, the centripetal pump is also the flow outlet of heavy liquid phase, which is convenient for pipeline layout.

1.2 Separation Range of 3 Phase Decanter Centrifuge
A. When the viscosity of liquid phase is small and the particle size of solid phase is large, the specific gravity difference between solid, liquid and liquid is required to be ≥ 0.05g/cm3 (solid heavy, liquid light).
B. When the liquid viscosity is small and the specific gravity difference between solid and liquid is large (the specific gravity difference is ≥ 1g/cm3), the solid particles shall be ≥ 0.005mm and the specific gravity difference between liquid and liquid shall be ≥ 0.05g/cm3.
C. When the liquid viscosity is large or the solid-liquid specific gravity difference is small and the solid particles are very small, the separation effect will be significantly reduced, even the equipment is not applicable.
D. When the solid particles are easy to be damaged, the separation effect will also be affected.

2. Comparison between 3 Phase Decanter centrifuge and other centrifuge equipment

2.1 Comparison with 2 Phase Decanter Centrifuge
GN 2 phase and 3 phase decanter centrifuges are branches of horizontal decanter centrifuge and their basic working principles are the same. The equipment relies on the high-speed rotation of its rotating assembly to form an acceleration thousands of times of the gravity acceleration inside the bowl, so that the substances to be separated will be stratified due to different densities; Then, through the differential gear box of the equipment, the bowl and the screw generate relative motion, so that the separated substances can be output. The difference is that the GN 2 phase decanter centrifuge is used for solid-liquid two-phase separation, and the solid slag and separation liquid are discharged from the opening at the bottom of the equipment collection box; While GN 3 phase decanter centrifuge adopts centripetal pump technology, which can realize solid liquid liquid three-phase separation. Solid slag and light liquid phase are discharged from the bottom opening of the equipment collection box by gravity, while heavy liquid phase is discharged through the flow outlet on the impeller under the pressure of the centripetal pump. In the world, there are also three-phase decanter centrifuges with heavy liquid and light liquid phase outlets provided by other equipment suppliers that are contrary to the design of GN Company, which is not to be detailed here.

2.2 Comparison with 3 Phase Disc Stack Separator
Different from 3 phase decanter centrifuge, 3 phase disc stack separator belongs to the category of vertical centrifuge. The rotating assembly rotates at high speed with the Y axis as the centerline, and the centrifugal force acceleration generated is one level higher than that of the three-phase decanter centrifuge. Therefore, the three-phase disc stack separator has better separation effect for solid-liquid or liquid-liquid separation with small specific gravity difference. It is worth noting that three-phase disc stack separator are often used for the treatment of materials with low solid content (no more than 3%), such as the clarification of liquid phase. Therefore, in some treatment processes, three-phase decanter centrifuges and three-phase disc stack separators are often used in series as upstream equipment and downstream equipment. First, use a three-phase decanter centrifuge to separate most of the solid phase from the material, and then use a three-phase disc separator to separate the heavy liquid phase (such as water) and light liquid phase (such as oil). In this way, the respective advantages of the two devices can be better used to improve work efficiency and obtain better processing effect. GN is also able to provide three-phase disc separator and two-phase disc separator to meet the diversified needs of customers.

3. Applications of 3 Phase Decanter Centrifuge

In practical applications, three-phase decanter centrifuges are often used as oil-water separation equipment. To achieve oil-water separation, a prerequisite is that oil-water mixture is non-emulsified, that is, it can be stratified under the condition of natural precipitation. The following are some common applications of three-phase decanter centrifuge.

3.1 Oil Sludge Treatment
The petrochemical industry often produces some waste oil sludge, mainly from the landing oil sludge at the oil field drilling site, the oil sludge at the bottom of the crude oil storage tank and the waste oil sludge in the production process of the refinery. The oil sludge treatment system independently designed by GN is a set of reduction treatment solution specifically for these sludge. After chemical de-mulsification treatment and coarse filtration, three-phase separation of oil, water and solids residue is required. GN three-phase decanter centrifuge is the main equipment for three-phase separation of oil sludge system. The separated oil can be sent back to the refinery for further processing. The oil content in the discharged solid residue is less than 3%, which provides great convenience for subsequent thermal desorption or biodegradation treatment.

3.2 Hogwash Fat Treatment
Hogwash, also known as kitchen waste, is a kind of food processing waste and food residue produced by food processing. Its composition is complex, with high water content and high oil content. If it is not handled in time, it is easy to rots, deteriorates and breeds parasites, molds and other harmful substances. Three phase decanter centrifuge is ideal equipment for kitchen waste disposal. The kitchen waste mixture after high-temperature cooking is crushed and filtered by the pulping machine, and then enters the three-phase decanter centrifuge for treatment. The separated solid residue enters the slurry mixing buffer tank for dilution and then undergoes anaerobic fermentation treatment or is made into organic fertilizer. The separated oil phase is used to extract biofuel after impurities are removed, and the heavy liquid phase can be converted into biogas through anaerobic fermentation.

3.3 Disposal of Byproducts in Slaughterhouse
Fat melting plants process slaughter by-products, such as cowhide, which are suitable for further use as food. Generally, there are two different processes for dealing with these by-products. After grinding and heating products, three-phase decanter centrifuges are traditionally used for separation in the first stage. In the second stage, the disc stack separator will separate the liquid phase coming from three-phase decanter centrifuge into fat, water and solid components. Usually, the fat is clarified with a second disc stack separator.

3.4 Fish Products
The separation process of three-phase decanter centrifuge has been the standard and mature process for fish meal production, mainly used to extract fish meal and fish oil from whole fish or fish head, fins, bones and other wastes. During processing, raw materials need to be heated and decomposed to produce fish oil. The steamed raw materials will be screened to obtain solid residue and liquid phase, and the solid residue will be pressed and dried to obtain fish meal. Fish oil, fish juice and residual solid residue can be obtained from the liquid phase after being processed by a three-phase decanter centrifuge.

3.5 Clarification of Plant Oil
Plant oil is an important raw material in modern life, such as olive oil, palm oil, rapeseed oil, etc. Some of these oils can be eaten and used in the catering industry and food processing industry, and some are used in cosmetics processing. After the oil is extracted from the plant fruit by crushing, grinding, or pressing, the oil contains a certain amount of water and fruit residue. The three-phase decanter centrifuge is often used to separate the water and residue from the plant oil, making the oil more clear. If you want to obtain more clear oil, you can add a disc stack separator to further process the oil.

3.6 Starch Production
Wheat is one of the most important raw materials to produce starch and its by-products in the world. Starch production includes the decomposition of wheat flour into A starch, pentosan and gluten or B starch. The more effective method is three-phase decanter centrifuge, which separates the whole A starch into concentrate, removes gluten from B starch, and separates light components.

3 phase decanter centrifuge is one of the centrifugal separation equipment of GN Company. As an original equipment manufacturer, GN is committed to providing users with cost-effective, energy-saving and environment-friendly separation solutions. For more information about three-phase decanter centrifuges, please no hesitate to contact GN Separation.

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Bruce Dong

Thomas Meng