Filter operator

Footnote 4 - The solubility of Ammonium Chloride in absolute Ethanol is 0.6g/100g at 15C. The solubility in n-Butyl Alcohol is neglible, even at its boiling point. If you use n-Butyl Alcohol, you will only need to perform 3 reflux/filter operations to obtain sufficiently pure Methylamine Hydrochloride. 

The Artisan continuous filter operates at pressures from 150 to 200 kPa, it allows washing by iajection of washflquid after the initial filtering stages, and the sizes available range from 0.3 to 19 m. Abrasive wear on the cloth is claimed to be eliminated by the thin protective layer of cake on the medium. 

Dynamic membranes are concentration—polarization layers formed in situ from the ultrafiltration of coUoidal material analogous to a precoat in conventional filter operations. Hydrous zirconia has been thoroughly investigated other materials include bentonite, poly(acryhc acid), and films deposited from the materials to be separated (18). 

In filter operation, it is essential that the gas be kept above its dew point to avoid water-vapor condensation on the bags and resiilting plugging of the bag pores. However, fabric filters have been used successfully in steam atmospheres, such as those encountered in vacuum diyers. In such cases, the housing is generally steam-traced. 

Since most batch-type filters operate under pressure rather than vacuum, the following discussion will apply primarily to pressure filtration and the various types of pressure filters. 

Polishing of solutions (as performed on a precoat filter operation). 

Design Example for a Batch Nutsche Filter Operation A batch Nutsche filter operates under constant pressure and maximum capacity with three stages filtration, washing and drying. The Nutsche filter with a 1 m filtration area operates under the following set of conditions ... 

Depending on the type of filter device, additional requirements may be made of the cloth. For example, in a plate-and-frame press, the sealing properties of cloths are very important. In this case, synthetic cloths are more applicable staple cloths, followed by poly filament and monofilament cloths. In leaf filters operating under vacuum and pressure, the cloth is pulled up onto rigid frames. Since the size of a cloth changes when in contact with the suspension, it should be pretreated to minimize shrinkage. 

Determine the required surface area of a Nutsch filter operating under the following conditions ... 

There are two modes of filter operation representing extreme eases of filtration viz. (1) eonstant rate and (2) eonstant pressure. 

This three-dimensional cutaway drawing illustrates the filtering operation of the QAF9 filter-bag pressure filter system, showing the flow patterns of unflltered liquid through a preselected micronrated felt filter bag which renders the desired quality of filtered product. 

This first step makes necessary a correction of the atmosphere aberrations by means of an adaptive optics or at the minimum a tip tilt device. If the turbulence induces high aberrations the coupling efficiency is decreased by a factor VN where N is the number of spatial modes of the input beam. Note that tilt correction is also mandatory in a space mission as long as instabilities of the mission platform may induce pointing errors. Figure 10 (left) illustrates the spatial filtering operation. This function allows a very good calibration of... 

The filtering operation can also be conveniently done in a high-quality nitrogen atmosphere dry box by vacuum filtration through a 90-mm., 60-ml., medium-porosity fritted-disk Buchner funnel. 

A slurry is being filtered at a net rate of 10,000 gal/day by a plate and frame filter with 15 frames, with an active filtering area of 1.5 ft2 per frame, fed by a positive displacement pump. The pressure drop varies from 2 psi at start-up to 25 psi after 10 min, at which time it is shut down for cleanup. It takes 10 min to disassemble, clean out, and reassemble the filter. Your boss decides that it would be more economical to replace this filter with a rotary drum filter using the same filter medium. The rotary filter operates at a vacuum of 200 mmHg with 30% of its surface submerged and rotates at a rate of 5 min/rev. If the drum length is equal to its diameter, how big should it be ... 

You want to select a rotary drum filter to filter a coal slurry at a rate of 100,000 gal of filtrate per day. The filter operates at a differential pressure of 12 psi, and 30% of the surface is submerged in the slurry at all times. A sample of the slurry is filtered in the lab through a 6 in diameter sample of the filter medium at a constant rate of 1 gpm. After 1 min the pressure drop across this filter is 3 psi, and after 5 min it is 10 psi. If the drum rotates at a rate of 3 rpm, what total filter area is required ... 

A rotary drum filter is to be installed in your plant. You run a lab test on the slurry to be filtered using a 0.1 ft2 sample of the filter medium at a constant pressure drop of 10 psi After 1 min you find that 500 cm3 of filtrate has passed through the filter, and after 2 min the filtrate volume is 715 cm3. If the rotary drum filter operates under a vacuum of 25 in.Hg with 25% of its surface submerged, determine ... 

A slurry containing 0.2 kg solids/kg water is filtered through a rotary drum filter operating at a pressure difference of 65 kN/m2. The drum is 0.6 m in diameter and 0.6 m long, rotates once every 350 s, and has 20% of its surface submerged in the slurry. 

You want to use a plate and frame filter to filter an aqueous slurry at a rate of 1.8 m3 per 8 hr day. The filter frames are square, with a length on each side of 0.45 m. The down time for the filter press is 300 s plus an additional 100 s per frame for cleaning. The filter operates with a positive displacement pump, and the maximum operation pressure differential for the filter is 45 psi, which is reached after 200 s of operation. 

Consider a highly resolved simulation of a set of microscopic TFM equations for a fluidized suspension of particles in a large periodic domain. The filtering operation does not require a periodic domain however, as each location in a periodic domain is statistically equivalent to any other location, statistical averages can be gathered much faster when simulations are done in periodic domains. After an initial transient period that depends on the initial conditions,... 

In order to implement the PDF equations into a LES context, a filtered version of the PDF equation is required, usually denoted as filtered density function (FDF). Although the LES filtering operation implies that SGS modeling has to be taken into account in order to capture micromixing effects, the reaction term remains closed in the FDF formulation. Van Vliet et al. (2001) showed that the sensitivity to the Damkohler number of the yield of competitive parallel reactions in isotropic homogeneous turbulence is qualitatively well predicted by FDF/LES. They applied the method for calculating the selectivity for a set of competing reactions in a tubular reactor at Re = 4,000. 

A rotary filter, operating at 0.03 Hz, filters at the rate of 0.0075 m3/s. Operating under the same vacuum and neglecting the resistance of the filter cloth, at what speed must the filter be operated to give a filtration rate of 0.0160 m3/s ... 

Filtration is carried out in a plate and frame filter press, with 20 frames 0.3 m square and 50 mm thick, and the rate of filtration is maintained constant for the first 300 s. During this period, the pressure is raised to 350 kN/m2, and one-quarter of the total filtrate per cycle is obtained. At the end of the constant rate period, filtration is continued at a constant pressure of 350 kN/m2 for a further 1800 s, after which the frames are full. The total volume of filtrate per cycle is 0.7 m3 and dismantling and refitting of the press takes 500 s. It is decided to use a rotary drum filter, 1.5 m long and 2.2 m in diameter, in place of the filter press. Assuming that the resistance of the cloth is the same in the two plants and that the filter cake is incompressible, calculate the speed of rotation of the drum which will result in the same overall rate of filtration as was obtained with the filter press. The filtration in the rotary filter is carried out at a constant pressure difference of 70 kN/m2, and the filter operates with 25 per cent of the drum submerged in the slurry at any instant. 

Data from the laboratory filter may be used to find the cloth and cake resistance of the rotary filter. For the laboratory filter operating under constant rate conditions ... 

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