Introduction to Centrifugal Dehydrator

As a debugging of sludge dewatering, the main task of its work is to find the optimal operating combination parameters between sludge, equipment, and flocculant based on existing conditions. Relying solely on one or ignoring the other can cause operational problems. Control these operating parameters well to ensure long-term stable operation, and make scientific and effective adjustments in a timely manner in case of changes on site, so as to still meet the requirements of cooperation, achieve good sludge treatment effect and high treatment efficiency under low flocculant consumption, thereby achieving low operating costs and meeting the requirements of good technology and economy. Adjustment of coagulants for changes in sludge properties and concentration

Instructions for Centrifugal Dehydrator

A、 Capable of handling dry solid load, which refers to the weight of non-volatile solid processed per hour, expressed in KGDS (dry solids)/h;

B、 The maximum hydraulic load that can be handled is the sludge flow rate entering the equipment, expressed in m3/h. The product of this and the incoming sludge concentration (solid content) is the dry solid load.

Under normal sludge concentration conditions, it is advisable to ensure that the dry solid load of the large treatment is 70% -90% of the theoretical load of the equipment calibrated by the equipment manufacturer. This is to avoid low equipment utilization and to prevent equipment wear and tear from accelerating and maintenance cycles from shortening due to long-term operation at high loads. In the case of excessive equipment load, no matter how much flocculant is used, the treatment effect will not improve. This is manifested as poor mud cake density, high solid carried by the supernatant, and decreased recovery rate. The overflow of sediment carried by the supernatant causes equipment wear, dynamic balance breakdown, and increased vibration. Sometimes, due to the increase in sludge concentration, the actual sludge load exceeds the acceptable load index of the equipment when entering the sludge at the original flow rate, resulting in a decrease in treatment efficiency. At this point, it is necessary to gradually reduce the frequency of mud feeding in a timely manner, observe the effect, and continue to try to control the flocculant flow rate to the economic dosage after the effect stabilizes. On the contrary, when the sludge concentration decreases, the inlet flow rate should be gradually increased, and the flow rate of the dosing pump should be adjusted simultaneously. If the sludge concentration is too low, although the dry solid load of the equipment is not high, the hydraulic load is large. The low concentration sludge entering cannot form an effective and uniform mud ring layer under high hydraulic load, and the settled solids will be carried over by a large amount of supernatant, directly affecting the treatment effect and efficiency. Therefore, for low concentration sludge, such as non concentrated sludge in the secondary sedimentation tank, it is better to undergo concentration treatment (such as concentration treatment by a thickener), or to be mixed with high concentration sludge (such as sludge in the primary sedimentation tank) and dehydrated. To avoid overloading the centrifuge due to excessive torque caused by excessive sludge load, it is necessary to appropriately reduce the frequency of the sludge pump. This situation mainly occurs when the sludge concentration increases while still operating at the original sludge flow rate.

Centrifugal dewatering machine style

Adjustment of flocculant dosing points

The different dosing points of coagulants will directly affect the mixing and reaction status of the sludge, thereby affecting the state, strength, and separation status of the flocs, ultimately affecting the consumption of coagulants and the effectiveness of sludge treatment. There are multiple options for adding coagulants, and in general, they can be set as adding before the sludge pump, adding through the sludge pump pipeline, and adding at the sludge inlet of the centrifuge. The specific setting and adjustment of dosing points are determined based on the properties of sludge, equipment characteristics, and flocculant characteristics, and are generally determined through practical application experiments.

At present, some manufacturers' centrifuges use the method of adjusting the position of the material mixture entering the centrifuge, and the specific adjustment can be determined according to the actual situation.

In the centrifuge, due to the large centrifugal force field, even small sludge can be separated from water, so the dosage of flocculant is relatively small. Generally, the dosage for dewatering mixed sludge is around 1.2 kg/tds, and the sludge recovery rate is over 95%. The moisture content of the dewatered sludge cake is 65% to 80%; In order to increase the processing capacity, the filter belt cannot be woven too tightly. To prevent small sludge from leaking into the net, more flocculants need to be added to form larger flocs in the sludge. Generally, the dosage for dewatering mixed sludge is greater than 3 kg/tds, and the sludge recovery rate is about 90%. After dewatering, the moisture content of the sludge cake is about 80%