Filtration data evaluation

In evaluating the process mechanism (assuming that one dominates) filtration data may be massaged graphically to ascertain the most appropriate linear fit and, hence, the... 

Comparative calculations of specific capacities of different filters or their specific filter areas should be made as part of the evaluation. Such calculations may be performed on the basis of experimental data obtained without using basic filtration equations. In designing a new filtration unit after equipment selection, calculations should be made to determine the specific capacity or specific filtration area. Basic filtration equations may be used for this purpose, with preliminary experimental constants evaluated. These constants contain information on the specific cake resistance and the resistance of the filter medium. 

In conclusion, the following experiments on filtration-washing-deliquoring should be performed to produce data (viscosity of liquids, effective solid concentration, specific cake resistance, cake compressibility, etc.) that are necessary to evaluate times of individual steps of filtration at an industrial scale, i.e. to obtain the proper basis for scale-up of filtration processes measure the filtrate volume versus time make marks on your vacuum flask and take down the time when the filtrate level reaches the mark => no more experiments are needed for preliminary evaluations of filtration properties of slurries initially fines pass the filter medium => recirculate them to the slurry,... 

D may be evaluated by Equation 6 by using the experimental data of Wg as a function of z, w,(z). D as determined by Equation 6 is the differental which, according to the Filtration Model proposed, should vary almost linearly with the variation of W,. The rate of solute contamination by the surface adsorption usual increases as the solute concentration in the completely melted zone Wj increases. The integral coefficient may be evaluated by... 

The identification of those variables that have a major effect on plutonium peroxide precipitation was done in two ways. The first way used t-test values associated with each variable. The comparative magnitude of these values indicates the relative importance of the variable. The second way involved a subjective evaluation of the relative importance of each of the variables based on a visual comparison of the graphs constructed from the experimental data (Figures 1 through 12 plus a couple of dozen other comparable graphs that could not be included in this paper because of space limitations). The results of the subjective evaluation indicate that only the nitric acid concentration and the rate of hydrogen peroxide addition have a major effect on the relative filtration time. The other four variables influence the... 

The larger the value associated with a variable, the more significant is the effect of that variable. On this basis, the variables that are most important to the relative filtration time are the nitric acid concentration and the rate of hydrogen peroxide addition. The variables most important to the plutonium concentration in the filtrate are the nitric acid, hydrogen peroxide and impurity concentrations. Thus, the t-test data is in general agreement with the subjective evaluation. 

The t-test data, as well as the subjective evaluation, show that the plutonium concentration in the filtrate is more sensitive to the variables of the precipitation than is the relative filtration time. 

Several leaf tests should be performed for repeatability. Data collected will permit scaleup to plant scale operations. Significant data will be pounds of dry cake per square foot per hour, gallons of filtrate per square foot per hour, filtrate clarity, wash ratios, (pounds of solids/gallon of wash), residual moistures, filtermedia selection, knife advance time, precoat thickness, solids penetration into precoat, and submergence level should also be evaluated. For the optimization equation, refer to Peters and Timmerhaus, and Tiller and Crump. 

Example 30.2. Laboratory filtrations conducted at constant pressure drop on a slurry of CaCOj in H2O gave the data shown in Table 30.2. The filter area was 440 cm, the mass of solid per unit volume of filtrate was 23.5 g/L, and the temperature was 25°C. Evaluate the quantities a and as a function of pressure drop, and fit an empirical equation to the results for a. 

Specific Resistance to Filtration. Specific resistance to filtration (SRF) is a standard method (34) for determination of the industrial amenability of a material to dewatering by filtration methods. Modifications of this method are useful empirical tools for evaluating interparticle interactions in concentrated suspensions. Figure 24 shows a schematic diagram of the apparatus in which the water released during filtration under standard conditions can be measured. Figure 25 shows data collected on oil sands mature fine tailings as a function of pH. As with the other methods, these data indicate that material is most difficult to handle at basic pHs. 

Results of calculation of apparent conductivity curves as a function of parameter Xi/ai = 10 /ai) l0pi/are presented in Figs. 8.1-8.5. These data permit us to evaluate maximal frequencies for which it is still possible to eliminate the influence of the borehole and the intermediate zone. For example, when there is a deep penetration of the filtrate into the formation az/ai 16) and az < (Jz the value of the apparent... 

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