Volume reduction factors

Combining these equations and integrating yield Cf = CioX for a volume reduction factor X = Q/Qo and the observed component passage Si. This allows one to determine either final concentrations from crossflow rates or the reverse. For a fully retained product (Sj= 0), a 10-fold volume reduction (X = 10) produces a 10-fold more concentrated product. However, if the product is only partially retained, the volume reduction does not proportionately increase the final concentration due to losses through the membrane. 

Batch or Fed-Batch Operation This mode of operation is typical of biologicals and juice processing where high solicfs and low fluxes require multiple passes, and batch operation is characteristic of the manufacturing process. Formulas in Table 20-19 can be used to calculate the required volume reduction factor X, diafiltration volumes... 

Incineration The incineration in an oxygen-rich atmosphere results in the oxidation of the initial feed material and produces a volume reduction factor ranging from 30 to 100. Incineration systems include, among others, rotary kiln and fluidized-bed incinerators (US DOE, 1998). 

For the treatment of low and intermediate level wastes, three processes are generally adopted, namely, chemical precipitation, ion exchange, and evaporation. The efficiency of the treatment scheme is judged by the values of decontamination factor (DF) and volume reduction factors (VRFs), which are defined as follows ... 

The process conducted in batch-type counter-flow apparatus (Figure 30.17) equipped with capillary PP Acccurel membranes showed good effectiveness of membrane distillation for purification of radioactive waste. Permeate obtained was pure water. All solutes together with radioactive compounds were rejected by the hydrophobic membrane. At tenfold volume reduction of the initial portion of waste, approximately tenfold concentration of radioactivity in the retentate stream was reached, while radioactivity of permeate retained on the level of namral background (Figure 30.18). As was observed in experiments small sorption in the system took place. However, permeate was free of radioactive substances and other dissolved compounds, the concentration and radioactivity factors sometimes slightly differed from volume reduction factors. 

Note Initial volume of feed 400 L final volume of concentrate 20 L volume reduction factor (VRF) 20 m Ci/L stands for millicuries per liter. ... 

Volume reduction factor under continuous operation 30... 

The membrane separation plant is tubular ultraflltration (UF) and the pilot-plant operation was on a batch basis with a volume reduction factor approaching 40. The UF membrane had a maximum permeate flux of around 300 L/m hr at maximum 6 kg/cm inlet pressure and 3.8 m/s fluid velocity with a clean membrane. The flux typically dropped and approached 80 L/m hr at the end of a day s operation. The retentate from UF separation was returned to the feed tank whereas the permeate was routed to the sewer. Design of a full-scale plant was performed using a flux value of 40 L/m hr and volume reduction of 20x. 

Batchwise concentration experiments were conducted with the four kinds of membranes under the selected operating conditions. Experimental results obtained in the batchwise concentration experiments are shown in Figure 22.9, where feed flow rate and operating pressure were 10 L/min and 4 MPa, respectively. Figure 22.9 shows changes in yield of each component with concentration factor, which is dehned as the ratio of initial feed volume to feed volume. Yield of creatinine and sodium decreased with increase in volume reduction factor, while that of anserine and carnosine was... 

Cell density (Cpsi) Geometry of the duct Hydraulic diameter (mm) Theoretical volume reduction factor... 

The figures compare the emission results obtained with 2 R.F.C. converters of respectively 1000 and 1600 cells/inch2 and a substrate volume of 0.76 litres. The results are compared with those of a 2.4 litres conventional 400 cells/inch2 converter. The total loading of the conventional converter was 3.4 g Pt/Rh (5/1) and the R.F.C. s had a total loading of 1.7g Pt/Rh (5/1). The following table 2 resumes the data in terms of volume reduction factors and precious metal loading reduction factors. All converters had metal substrates and are in fresh conditions. 

Figure 6. Mass balance approach to fractionation of dissolved organic matter and organometallic complexes by ultrafiltration (K = 1000 mol wt V = volume (L) a = volume reduction factor)...

The sequential ultrafiltration procedure was tested using known initial concentrations of the appropriate metal nitrate salt in Milli-Q water. Volume reduction factors were noted and metal concentrations for each retentate fraction were measured. From these values the mass... 

When a decrease of the original volume (via solvent extraction, distillation, or evaporation, etc.) is required before analysis, back calculations must be carried out to determine the original volume that must be collected to give the desired measurable level of the parameter. For example, if Vj is the volume calculated from the use of Ms and R, then the required original volume Vq is obtained from the product of Vi and the volume reduction factor For a volume reduction of 100, Vo would be lOOVi. 

In this formulation no allowance is made for the reduction in free volume when the cage contains only one adsorbate molecule. It is somewhat more logical and consistent to write the Henry constant as the product of a hypothetical constant for a point molecule (/k ) and a free volume reduction factor reflecting the size of the actual molecule so that in place of Eq. (3.100) we have... 

The volume reduction factor (VRF) in UF and MF processes is defined as the ratio between the initial feed volume and the volume of the resulting retentate given by ... 

A great number of processes are available for producing acceptable waste packages. Such processes should be selected on the basis of the characteristics of the waste concerned, with due account taken of radioactive decay. If possible, processes with high volume reduction factors should be applied with the use of proven techniques such as compaction or incineration. 

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