Filtration tests

Hannon, D. and B. Damin (1993), New diesel low temperature operability. AGELFl filtration test . CEC 4th International Symposium, Birmingham. 

Precoat Procedure Precoat filtration tests are run in exactly the same manner as bottom-feed tests except that the leaf must first be precoated with a bed of diatomaceous earth, perhte, or other shave-able inert sohds. Some trial and error is involved in selecting a grade of precoat material which will retain the filtered solids to be removed on the surface of the bed without any significant penetration. During this selection process, relatively thin precoat beds of I to 2 cm are satisfactory. After a grade has been selected, bench-scale tests should be... 

It is advisable to start a constant-pressure filtration test, like a comparable plant operation, at a low pressure, and smoothly increase the pressure to the desired operating level. In such cases, time and filtrate-quantity data shoulci not be taken until the constant operating pressure is reahzed. The value of r calculated from the extrapolated intercept then reflec ts the resistance of both the filter medium and that part of the cake deposited during the pressure-buildup period. When only the total mass of diy cake is measured for the tot cycle time, as is usually true in vacuum leaf tests, at least three runs of different lengths should be made to permit a rehable plot of 0/V against W. If rectification of the resulting three points is dubious, additional runs should be made. 

FIG. 18-108 Bomb filter for small-scale pressure filtration tests. [Silverhlatt etal., Cbem. Eng., 81(9), 132 (1974), hy permission.]... 

More detailea descriptions of small-scale sedimentation and filtration tests are presented in other parts of this section. Interpretation of the results and their conversion into preliminary estimates of such quantities as thickener size, centrifuge capacity, filter area, sludge density, cake diyness, and wash requirements also are discussed. Both the tests and the data treatment must be in experienced hands if error is to be avoided. 

During the filtration test of a water suspension containing 14.5 % calcium carbonate in a filter press (A = 0.1 m 50 mrn cake thickness temperature 23 C), the following data were obtained ... 

A suspension is to be processed in a filter press to obtain 6 m of filtrate in 3 hours. A filtration test in the lab under the same pressure and cake thickness showed that the filtration constants for 1 m of filter area are as follows K = 20.7 x 10-4 mVhr and C = 1.45 x 10 m /m. Determine the size of the filter. 

The following data were obtained in a filtration test using a CaCOj suspension on a filter of area A = 500 cm at constant pressure ... 

Filtration. The API filtration test for oil-base muds usually gives an all-oil filtrate. The test may not indicate downhole filtration, especially in viscous oils. The alternative high-temperature-high-pressure (HT-HP) filtration test will generally indicate a pending mud problem by amount of fluid loss or water in the filtrate. 

The instruments for the HT-HP filtration test consist essentially of a controlled pressure source, a cell designed to withstand a working pressure of at least 1000 psi, a system for heating the cell, and a suitable frame to hold the cell and the heating system. For filtration tests at temperatures above 200°F, a pressurized collection cell is attached to the delivery tube. The filter cell is equipped with a thermometer well, oil-resistant gaskets, and a support for the filter paper (Whatman No. 50 or the equivalent). A valve on the filtrate delivery tube controls flow from the cell. A nonhazardous gas such as nitrogen or carbon dioxide should be used for the pressure source. 

Maitlis filtration test. To investigate whether the Pd-doped perovskite is the actual catalyst, or a reservoir of soluble Pd, a Maitlis filtration test (10) was performed. The reaction of 4-bromoanisole with 4-phenylboronic acid, catalyzed by BaCeo 95Pdo os02 95, was intemipted at 20 s and 1 min, corresponding to conversions of 16 and 45%, respectively, by filtering the hot reaction mixture to remove the solid perovskite. The filtrates were allowed to cool to room temperature without stirring. After 3 h, the biatyl yields in both samples were estimated to be 100% by H NMR. 

Filtration Test. The filtration test equipment consisted of a glass column, with a fritted disc 2 cm. diameter, fitted with a stopcock and a 25 ml graduated cylinder. After mixing the MCC sols with electrolyte solution, the mixture was immediately poured into the glass column with the stopcock closed. The time required to collect water (blank) and filtered sol between 5 to 25 mis in the graduated cylinder after 2 hrs. was determined. The fritted glass was backwashed with water thoroughly after each measurement and a new blank was established. The relative filtration time between sample and water was used to compare differences between samples. 

Long-Term Cross-flow Filtration Test with Fischer-... 

Results from constant differential pressure filtration tests have been analyzed according to traditional filtration science techniques with some modifications to account for the cross-flow filter arrangement.11 Resistivity of the filter medium may vary over time due to the infiltration of the ultrafine catalyst particles within the media matrix. Flow resistance through the filter cake can be measured and correlated to changes in the activation procedure and to the chemical and physical properties of the catalyst particles. The clean medium permeability must be determined before the slurries are filtered. The general filtration equation or the Darcy equation for the clean medium is defined as... 

FIGURE 15.3 Variation of permeate flow against time in a typical cross-flow filtration test. 

The prototype shell-and-tube type cross-flow filtration modules (Pall Corp.) used for filtration tests are welded into a stainless steel shell enclosure. The modules have an inlet (filtrate) and outlet (retentate) port (both at tube sides) with Vi-inch tubing ends, and a permeate port, located near the midpoint of the shell side of the unit. The stainless steel filter membranes have a nominal pore size of 0.1 pm. The surface of the filter media is coated with a proprietary submicron layer of zirconia. 

The cross-flow filtration test unit is depicted schematically in Figure 15.4 it allows several types of cross-flow filter media to be studied under simulated FTS conditions. The filtration piping and instrumentation are heated via several circuits... 

FIGURE 15.4 Schematic of the cross-flow filtration test platform. 

A blend of Polywax 500 and 655 (81.3 and 18.7 wt%, respectively) with a CO-activated ultrafine iron catalyst was used for the evaluation of catalyst/ wax slurry filtration performance of the filter module with and without an alcohol compound. All of the filtration tests were conducted with a TMP of... 

MD M28 rocket propellant and burster hydrolysates slurried with shredded and micronized dunnage that has had the hydrolyzed aluminum removed by filtration. These tests included the results of aluminum filtration tests. This test also demonstrated a modified chemistry for controlling solids transport through the reactor without the use of an additive that degrades the titanium reactor material. 

Ruth et alS4-7) have made measurements on the flow in a filter cake and have concluded that the resistance is somewhat greater than that indicated by equation 7.1. It was assumed that part of the pore space is rendered ineffective for the flow of filtrate because of the adsorption of ions on the surface of the particles. This is not borne out by Grace18 or by Hoffing and Lockhart(9) who determined the relation between flowrate and pressure difference, both by means of permeability tests on a fixed bed and by filtration tests using suspensions of quartz and diatomaceous earth. 

A variety of SCS and PCP Pd (II) pincer complexes were prepared and immobilized on polymer or silica supports. (Figure 2 shows supported PCP complexes on poly(norbornene) and silica). Insoluble supports such as mesoporous silica and Merrifield resins along with soluble supports such as poly(norbornene) allowed for generalization of our observations, as all immobilized catalysts behaved similarly. The application of poisoning tests, kinetics studies, filtration tests, and... 

Failure of sensitive filtration tests such as ASTM D-2276, Particulate Contamination in Aviation Fuel by Line Sampling, can be due to caustic neutralized corrosion inhibitor salts. Sodium or calcium salts of dimer-trimer fatty acid corrosion inhibitors are gel-like in character. Filtration of jet fuel containing gelled corrosion inhibitor will be impeded due to plugging of fuel filter media by the inhibitor gel. This slowdown of filtration can result in failure of jet fuel to pass this critical performance test. 

Fig. 2.1.6.4 Hot filtration test and catalyst recycling for hydrogenation of dimethyl itaconate over RhDuphos/ AI-SBA-15.

In order to prove that the reaction was catalyzed heterogeneously and to exclude the possibility of leaching and homogeneous catalysis, hot filtration tests were performed [44]. For the dimethyl itaconate hydrogenation, removal of the COD-RhDuphos immobilized on Al-SBA-15 effectively stopped the reaction after 5 h. After 24 h, the conversion of the filtered sample remained at 40%, whereas the original batch with catalyst was converted completely (Fig. 2.1.6.4). 

A minimum of ten negative product control containers may be adequate to simulate manipulations by the operator during a membrane filtration test. An equivalent number of samples to the test samples may be necessary to simulate the manipulations of the product by the operator during a direct inoculation test. 

Constants of the Filtration Equation from Test Data Filtration tests were performed on a CaC03 slurry with properties ... 

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