In view of the problem that the filter press blocks the filter cloth and the mud cake appears "runny", choosing the right sludge conditioner is the key to solve the problem. Here are some suggestions for your reference:
1. Analyze the reasons
Clogging filter cloth:
May be due to the small particles in the sludge, large viscosity, easy to form a layer of difficult to remove filter cake on the filter cloth, resulting in clogging of the filter cloth.
It may also be due to improper selection of conditioner, resulting in poor flocculation effect of sludge, making it difficult for sludge particles to form an effective filter layer on the filter cloth.
Mud cake "runny" :
It is usually due to the fact that the water in the sludge is not fully removed, resulting in a higher water content inside the mud cake, forming a "runny" phenomenon.
This may be due to the poor dewatering effect of the conditioner, or the insufficient dosage of the conditioner, which cannot make the sludge form a tight floc structure.
Two, choose the right sludge conditioner
Selection of inorganic conditioner and organic conditioner:
Inorganic conditioner: such as iron salt, aluminum salt, etc., usually a large amount of dosage, the formation of fine floc particles but high strength. It is suitable for sludge dewatering with vacuum filter and plate and frame filter press. However, it is necessary to pay attention to the problem of clogging the filter cloth that may be caused by aluminum salt.
Organic conditioner: usually the dosage is small, the formed flocs are thick but low in strength, and the flocs formed by inorganic conditioners are more likely to break. It is suitable for sludge dewatering with centrifugal dewatering machine and belt filter press. However, the organic conditioner can also cause the mud cake to appear "runny" phenomenon, so it needs to be chosen carefully.
Consider sludge properties:
For sludge with high organic matter content, the more effective conditioner is cationic organic polymer negative conditioning ion dosage form, and the higher the organic and polymer organic matter conditioning content agent is.
Suitable for 3 choices. The higher the degree of polymerization, the higher the conditioning of the agent, the ion concentration type and the organic polymer plus the conditioning sequence agent.
Preparation concentration: The preparation concentration of organic polymer conditioner has a significant influence on the conditioning effect. In general, the lower the concentration, the less the drug consumption, the better the conditioning effect. But too high or too low concentration will reduce the yield of mud cake. The conditioning effect of inorganic polymer conditioner is almost not affected by the preparation concentration.
Dosing sequence: When the inorganic conditioner and organic polymer conditioner are used to combine the sludge conditioning, the inorganic conditioner is usually added first, and then the organic polymer conditioner is added to achieve a better conditioning effect.
Consider other factors:
The pH value of the sludge: affects the form of the hydrolysate and the conditioning effect of the conditioner. It is necessary to select the appropriate conditioner according to the pH value of the sludge.
Sludge temperature: affect the hydrolysis of inorganic salt conditioner. When the temperature is low, the hydrolysis will be slow, and the conditioning effect may be poor.
Three, comprehensive selection
In the selection of sludge conditioner, it is necessary to consider the nature of the sludge, the type of dewatering equipment, the type and characteristics of the conditioner, the preparation concentration and dosing sequence, and the pH value and temperature of the sludge. Through the test and evaluation, the best type and dosage of conditioner are determined to solve the problem of "runny" in blocking filter cloth and mud cake by filter press.
In addition, the use of compound conditioners or new conditioners can also be considered to further improve the dewatering effect of the sludge and the quality of the mud cake. At the same time, optimizing the sludge dewatering process and operating conditions is also an important way to solve the above problems.