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Belt filter press processing capacity calculation method

The processing capacity is one of the main technical and economic indicators involved in the application of belt concerns and practical engineering applications. It is an important indicator to evaluate the overall performance of the belt filter, and the calculation method of the belt filter processing capacity is applied to each of the belt filters. It has a certain role.
       1. The thickness of the wet cake produced by the belt filter is the main calculation parameter. Based on the calculated output of the wet cake, the amount of feed, ie the processing capacity, is calculated. The formula is as follows:
       Mud cake yield, wet cake - wet cake output t/hB - width of filter belt m ξ - filter belt width utilization factor, generally take 0.85 ~ 0.9 δ - wet cake thickness m, generally take 6 ~ 10mm (0.006 ~ 0.01m) v- filter tape with the actual working speed m/min generally take 3 ~ 6m/mins - unit time 60min / h γ- wet cake specific gravity t/m3, generally take 1.03 feed amount - single filter Processing capacity, t/h from above.
       The calculation formula can be seen that this kind of calculation method is based on the main calculation parameters of the wet cake thickness produced by the belt filter, while the wet cake thickness is formed on the one hand and the filter operating parameters such as the filter belt running speed and the filtering pressure. There is a big relationship; on the other hand, it also has a lot to do with the properties of the sludge such as solids concentration, viscosity, and the specific resistance of the sludge after conditioning. The formation of wet cake thickness also depends on the structural design of the filter. For example, the length of the concentration section, the capacity of the concentration section, the filtration time and the filtration period, and the selection of the air permeability of the filter belt.
       The linear relationship in the calculation formula, wet cake thickness selection range of 3 ~ 10mm, and the thickness of the wet cake formed in the actual operation of many belt filter is not uniform within the width of the filter belt.
       The calculation method is not combined with the main technical parameters of the concentrating section, the press section and the main property parameters of the sludge, and does not reflect the effect of sludge dosing conditioning, design of the filter structure parameters, changes in operating parameters, etc. The influence of the filter processing capacity, and the calculated value range of the wet cake is relatively large, which is generally applicable to the design and selection of the belt filter, and has little significance for optimizing the structure design and guiding the operation of the belt filter.
       2. Sludge dewatering system for municipal sewage and industrial waste water. Sludge should be conditioned before sludge dewatering. The purpose of adding medicine conditioning is to improve the dewatering performance of the sludge, reduce the water affinity in the sludge, reduce the filtration resistance ratio r of the sludge and the capillary water absorption time CST. At the start of filtration, the filtrate must overcome the resistance of the filter medium. After the filter cake is formed, it must also overcome the resistance of the filter cake itself, which is the basic form of filter cake filtration. The Karman filtration basic equation deduced from the basic principle of the flow of the liquid through the filter residue layer can be used to calculate the filtration yield. According to the Karman filter basic equation:
      1 where: V-filtrate volume m3 t - filtration time P - filtration pressure PaA - filtration area m2 μ - kinetic viscosity of the filtrate Pasω - filtration unit volume filtrate dry weight retained on the filter medium kg/m3 r - ratio Resistance m/kg, the resistance of the filter cake, is defined as the resistance per unit of dry weight of the unit filter area Rf - the impedance of the filter medium 1/m2 where: Q0 - the amount of sludge into the treatment (processing capacity) m3Qf- Filtrate m3 Ck - Solids concentration in the filter cake kg/m3 According to the liquid phase equilibrium: Q0 = Qf Qk According to the solid phase equilibrium relationship: Q0C0 = QfCf + QkCk Where: C0 - Solids concentration in the raw sludge g/LCf - The concentration of solids in the filtrate is g/L. The sludge dewatering system generally requires a solids recovery rate of 95%. The Cf value is very small. The actual calculation is based on the definition of the filtration yield. Cf Qk - The amount of filter cake L The weight of filter biscuit produced in the area is kg/(m2s) or kg/(m2h). For calculation purposes, tentatively set the impedance of the filter media Rf = 0, then the basic equation of Carmen filter equation 1 becomes: Set filter biscuit weight to W, then W = ωV, V = W / ω substitution, band filter processing capacity L For: (kg/m2.s) 5 formula is another calculation formula for the processing capacity of the belt filter. For the sludge dewatering system of municipal wastewater treatment plants, the specific resistance of the sludge is controlled at 1012m/kg after the sludge is conditioned by adding chemicals. For the belt filter, the specific resistance of the sludge after conditioning by the drug in the laboratory is generally At 1012m/kg. At an ambient temperature of 20, the kinematic viscosity of the sludge is μ = 0.001 Pas.
       When using the 5 formula, the belt filter integrated machine should be divided into two parts: the concentration section and the press section. The concentration section is dewatered by gravity filtration. The filtration pressure P is calculated according to the height of the sludge in the sludge section of the concentration section. The concentration C0 is the infiltration concentration, and the concentration of sludge in the concentration section of Ck is generally 810%. The filtration time t is determined by the length of the concentration section and the travel speed of the filter belt. For the press section, the pressure P is calculated by the filter belt tension, the contact area between the press roll and the filter belt, the concentration C0 entering the press section is the concentration of the concentrated sludge (8 to 10%), and the Ck is the filter cake concentration (25% to 20). %), filtration time t=m/T, m=ts/T (ie t=ts/T2), ts is the actual filtration time, the contact length between the filter belt and the press roll, and the filter belt operating speed are filtered Cycle (press section run time). The sum of the amount of treatment of the concentration section and the press section is the processing amount of the belt filter. Since the impedance Rf of the filter medium of the filter medium is not taken into consideration in the calculation, the resistance Rf of the filter belt is related to the material of the filter belt, the ventilation volume, etc., so the processing amount should be the above-mentioned processing amount multiplied by a coefficient, generally taking 0.9~ 0.95 is the throughput of the belt filter.
       Although the latter method is complex, the calculation method includes the influence of the design parameters of the belt filter structure, the sludge property parameters, the operating parameters, etc., and the calculated amount is calculated by an example. The filter processing capacity plays a major role.

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