Filtration pressure tests

FILTRATION LEAF TEST DATA SHEET - VACUUM AND 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. 

Unite the two lots of moist impure KNOa, add half their weight of distilled water, and heat until solution is complete. Cool to 10° and filter, pressing out as much as possible of the liquid. Stop suction. Pour 15 cc. ice cold distilled water over the crystals and let it permeate the mass. Apply suction and pressure. Test for chloride. If any is found repeat the washing process until the product is free from chloride. Add all filtrates to the mother liquors, G. 

The pump has a throttling valve that relates pressure drop to flow rate Q as follows Ap (throttling) = 15(g/500)2. The temperature varies from 20 to 27°C (68 to 80.6°F). A series of constant-pressure tests yielded the data on aav and (1 — eav) shown in Fig. 14.4, aav being the average specific filtration resistance and eav the average porosity of the cake. Find cake thickness as a function of time. 

The integrity of the filter assembly should be checked by an appropriate method, such as a bubble-point pressure test or forward-flow pressure test immediately before and after use. Abnormal filtration flow-rates should be noted and investigated. Results of these filter-integrity checks should be recorded in the batch record. 

Assembly drawing—orientation of feed, discharge, and drain nozzles Operating pressure, test pressure Safety vents Filtration area provided... 

For constant levels of pressure, e erimental data plotted in the form of t/V, V will exhibit either an increasing intercept on the ordinate of the graph in circumstances v 4iere particle penetration is occurring or a nonlineai, initial portion of the graph. Of course, here it is necessary to use new doth material in each pressure test in order to isolate possible causes of blinding other than bridge collapse. The state of the cloth pores after filtration can also be examined microscopically to check for particle penetration. 

Constant prcs we filtration readings from vacuum or pressure test cake and cloth resistance follows from equation (2.23)... 

Pressure, Flux, Frequency, and Duration of Backwash Backwashing conditions such as pressure, flux, frequency, and duration, in practice, are usually obtained by trial and error. Kennedy et al. (1998) studied the backwash conditions in order to maximize the net flux per filtration cycle. They found that increasing the backwash to filtration pressure ratio (Ph/Pf) above 2.5 did not result in any significant increase in flux restoration within the range of backwash pressures tested (0.2—1.6 bars) (Fig. 6.15). Their conclusion that applying high backwash pressures (8 limes the filtration pressure) cannot restore irreversible flux decline was in agreement with membrane suppliers recommendations. 

Cool the flask in ice, acidify with 10 ml. of cold 1 1-hydro-chloric acid and distil under reduced pressure (water pump) until most of the alcohol is removed. Add water to the residue, extract several times with ether, wash the combined ethereal extracts with N ammonia solution until a test portion gives no precipitate upon acidification. Extract the combined alkahne solutions once with a fresh portion of ether, and add the aqueous solution to an excess of dilute hydrochloric acid the final mixture should still be acidic to Congo red. Collect the crystalhne half-ester by filtration at the pump, wash it with water and dry at 100°. The yield is 14-5 g., m.p. 122-125°. Recrystallise by dissolving in about 40 ml. of warm benzene and adding an equal volume of petroleum ether (b.p. 40- 60°) 13 -5 g. of the colourless half-ester, m.p. 125-126°, are obtained. 

Filters for use in sterile gas filtration must conform to standards similar to those mandated for sterile hquid filtration. Nondestmctive integrity tests may be apphed. The tests are performed by wetting the filter with an appropriate solvent, commonly 60/40 isopropyl alcohol/water for hydrophobic membranes, and applying air or nitrogen gas at a preset pressure. 

---