Filtration efficiency calculations

Fig. 6 shows the variation in and residual pressure drop during six hours of operation. K is calculated from Eq. 4. Calculated mean specific cake resistance equals 6.5-10 [s ], with a standard deviation of approx. 15%. is defined as the velocity across the exposed filter surface (vy 2 U,). Observed fluctuations in pressure build-up did not result in any increase in the residual pressure drop. The residual pressure drop could be maintained at a constant level. The average filtration efficiency was 0.9983. Filter regeneration was conducted with off-line pulsing (P,a = 2barg and total sand spill of 10 kg). 

Average dust concentration downstream of the filter unit was measured to be well below 5 mg/Nm. Measured filtration efficiency at 190 C and 9 cm/s corresponds to a filter efficiency above 99.83%, verified in a full-scale pilot plant. Calculated average... 

Figure 2.28 Simulation of a three-state single-molecule protein folding experiment in which the FRET value changes abruptly between 0.3, 0.5 and 0.7. The overall count rate is 1000 Hz. (a) Simulated data, acceptor in black and donor in gray, (b) Simulated data after filtration with the filter, (c) FRET efficiency calculated from a. (d) FRET efficiency calculated from b. (e) Histogram of the FRET efficiency values of c. (f) Histogram of the FRET efficiency values of (d).(Reprinted from Haran, G, Noise reduction in single-molecule Fluorescence trajectories of folding proteins. Chemical Physics 307 (2004) 137-145. (Copyright (2004) with permission from Elsevier.))...

Diffusion losses of aerosol nanoparticles can be quantified for empty filter housings under various conditions and with different orientations. Assessing and understanding the diffusion losses associated with filter housing interior volumes is important for the following reasons. Filtration efficiency is commonly calculated using Equation 3 below ... 

Before releasing a process column for chromatography, it is advisable to perform some test to measure efficiency, such as calculating height equivalent theoretical plates (HETP), both to forestall any problems in the column bed and to provide a benchmark by which to measure column reproducibility and predict degradation of the bed or material. Examples of compounds that are relatively innocuous for use in pharmaceutical applications are 1% NaCl (for gel filtration), concentrated buffer solutions (for ion exchange), and benzyl alcohol and parabens for reverse phase LC.10... 

In another application, Esy-GC-ECD was applied to the extraction of 14 organochlorine pesticides (OCPs) in spiked and contaminated complex samples, such as raw leachate water and soil-water slurry samples.94 A downsized filtration vessel was deemed crucial for sample filtration after acidification and the addition of activated copper granules (to remove elemental sulfur) and 20% acetonitrile (to prevent adsorption and enhance enrichment). Under optimal conditions, extraction of a 3-mL leachate water sample dispensed at a flow rate of 100 pL min-1 gave Ee values between 32 and 242 and LODs between 1 and 20 ng I. It was also demonstrated that, since ESy extraction is dynamic and its extraction efficiency low, calculation of relative recovery was more relevant than extraction efficiency in all ESy applications. 

The dimensions of a bag in a filter unit are 8 in. in diameter and 15ft long. Calculate the filtering area of the bag. If the filtering unit consists of 40 such bags and is to treat 480,000 ft /h of gas from an open-hearth furnace, calculate the effective filtration velocity in feet per minute and acfin per square foot of filter area. Also calculate the mass of particles collected daily if the inlet loading is 3.1 gr/ft and the unit operates at 99.99-b% collection efficiency. 

The capacity of a pnrification process to clear viruses is demonstrated at a representative small scale nsing model viruses. The most common model viruses used in this validation study are xenotropic murine leukemia virus (x-MuLV), mouse minute virus (MMV), and reovirus (Reo). The viral clearance capacity of the chromatographic steps, inactivation steps, and the viral filtration step is demonstrated by spiking a known amount of a model virus into the load of each of these unit operations and calculating the efficiency of removal by measuring the remaining viral titer in the product containing fractions. 

The main cost drivers for the pertraction process are the flow rate of the water stream to be treated, the required removal efficiency, and the nature of the components to be removed. All relevant parameters have been incorporated into a comparative cost model [103] developed for pertraction and the conventional technologies of air stripping and activated carbon treatment. The cost model for each of the technologies is based on the same assumptions in order to obtain comparable results. The result of the cost models is the total treatment cost per cubic meter of water treated. This cost includes depreciation of the installation, energy costs, maintenance, and operation. Table 4.5 shows typical results of the cost calculations for trichloroethene based on a water flow of 10 mVh with an inlet concentration of 10,000 pg/L. The outlet concentration of trichloroethene is a variable and lies in the range of 1000-1 pg/L. The results show that in all calculated cases, pertraction is more cost efficient than the alternatives (air stripping or activated carbon filtration). 

These results make it possible to compare the efficiency of adhesion of various filter materials. For this purpose it is necessary to calculate the Reynolds number for the particular filter charge and filtration velocity ... 

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