Monthly Archives: February 2022

The favorable factors of decanter centrifuge for biogas digester

Analysis of the use effect of Decanter centrifuge:

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1) In the past, the volume of the biogas tank built by the farmer was too small, and the drainage time after the sewage entered the tank was too short, resulting in excessive discharge of sewage concentration. Use the decanter centrifuge to process the sewage before it sinks into the pool, which can effectively reduce the COD and BOD content of the sewage, reduce the operating load of the biogas digester, and thus achieve the reduction of sewage discharge;

2) The use of decanter centrifuge in advance can transform the feces in the fresh sewage into valuable fish feed or organic fertilizer. The separated sewage intermittently enters the biogas digester, so that the anaerobic digester can have a full digestion time, so that the active bacteria in the digester can reproduce more vigorously, the gas production is higher, and the content of gas methane is naturally higher High purity will be overcome naturally to solve the problem of abnormal operation of biogas generators;

3) The sewage treated by the decanter centrifuge enters the biogas digester, which can effectively solve the crust phenomenon of the biogas digester and eliminate the work of cleaning the biogas residue;

4) The use of decanter centrifuge can reduce the investment in the construction of biogas digesters, for example: a breeding or slaughterhouse that discharges 100 tons of sewage per day. If a matching decanter centrifuge is used for pre-treatment, it can reduce the 300 cubic anaerobic tank Construction investment, because the concentration of manure and sewage mixed into the pond is too high, the anaerobic time will need to be extended accordingly, so if a farm that discharges 100 tons of sewage per day, without decanter centrifuge treatment, then an anaerobic pond 1000 is needed -1200 cubic meters, if using decanter centrifuge can reduce the construction of 300-400 cubic meters.

Explosion-proof performance of decanter centrifuge

 If the materials processed by the Decanter centrifuge contain flammable and explosive substances such as organic solvents, the centrifuge should have explosion-proof performance. The explosion-proof performance is determined according to the explosion-proof requirements of the process. The explosion-proof occasions involved in the past have only been proposed to be equipped with explosion-proof motors. In the past two years, most of the occasions where the processed materials contain organic solvents such as solvents have been required by nitrogen protection. In fact, to realize the explosion-proof in the true sense, centrifuges must take various measures in mechanical, electrical control, accessory configuration and other aspects.

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For instance: electric control system: explosion-proof isolation barrier, non-contact energy consumption braking system, electrostatic grounding, automatic control of explosion-proof.

Mechanical system: explosion-proof motor, explosion-proof lighting, anti-collision measures, anti-static transmission belt.

Explosion-proof accessories: nitrogen protection device, nitrogen online detection, on-site explosion-proof control button.

GN Explosion proof electrical control panels or electrical control stations are used in hazardous Location. The Ex control panel is designed and built to operate in environments where concentrations of flammable gases, vapors, liquids or combustible particles pose risks of ignition and explosion. GN Solids Control provide explosion proof control panel with ATEX approval, IECEX Approval, China National explosion proof approval. The protection degree is up to IP65 for weather and dust proof.

GN explosion proof control panel enclosures are cast from heavy duty aluminum so that they cannot create a spark that could possibly ignite the vapors in a hazardous location. These heavy duty panels come with seals keep explosive fumes from entering the control panel. Moreover the GN explosion proof control panels are designed to contain an internal explosion without igniting the explosive vapors present in the hazardous area to make sure it is safe for the hazardous Zone 1 or Zone 2 areas.

GN Explosion Proof Pressurized Control Panel is popular used for VFD controland soft starter of motor, especially in high temperature ambient. The explosion proof pressurized control panel consists of main cavity and auxiliary cavity. The main cavity is pressurized cavity which includes electrical components, pressure check sensor system, ventilation air distribution system, and air conditioning system. The purging system works automatically to maintain a certain positive pressure inside the main cavity.

GN Solids Control is capable to provide you with IEC Ex, ATEX or CNEx Standard Positive Pressurized Control Panel control panels with Zone 1 or Zone 2 for hazardous locations. This will also suit the North America Class I Division 1 or Division 2 hazardous locations application.

Selection and Application of Polymer Flocculants


For solids control fields, it’s very important to know some points about the selection and application of polymer flocculants, here are some advice from GN Separation:

2022.01.05 Mud Tank System

Selection of species: The action mechanism of flocculants is charge neutralization polymer bridge, so anionic and cationic flocculants should be selected according to the charge characteristics of the separated materials.

Selection of dosage: The best dosage of flocculant is that the flocculant is completely adsorbed on the surface of the solid phase particles and the flocculation sedimentation speed reaches the maximum. When the flocculant exceeds the optimal amount, the flocculation effect will decrease.

Selection of molecular weight: The larger the molecular weight of the flocculant, the stronger the capture power of solid particles, and the better the flocculation effect. If the molecular weight of the flocculant is too small. No flocculation effect will be achieved. For sludge dewatering, the selected molecular weight must be 3 million.

Shear strength of flocculant: Flocculants used in belt filter presses and decanter centrifuges have different shear strength requirements. High for general decanter centrifuges. And in the small sample test, you need to use a stirrer to verify the intensity of different stirring.

Selection of the feeding position; after flocculant is added, the flocculation settling speed is faster. If it is transported through a long-distance pipeline, it will easily cause pipeline blockage. According to tests, it is best to dissolve the flocculant solution with good solubility. Add at the decanter centrifuge inlet

Dissolving method of flocculant: High-speed mechanical stirrer cannot be used to dissolve the polymer flocculant, because the strong mechanical stirring will destroy the molecular chain of the flocculant, and the effect of the flocculant will be significantly reduced. Generally, the stirring speed of the dissolving flocculant is less than 50 rpm, and it is appropriate to divide it. The blade of the mixer should be as wide as possible. Studies have shown that the flocculant is 0.4 to 0 after being added to water. 6MPa compressed air bubbling is the best method to dissolve the flocculant-the dissolution is very uniform and the dissolution rate is extremely fast.