Improving Filterability

The filterability of a filter cake can best be improved by changing the properties of the crystals. By plotting the filtered volume Vas a function of time in the form t/V versus V (Equation 14.3) different cases, lab and plant, as well as different crystallizations can be compared. 

In certain cases, filter aids can be used to improve the filterability of a suspension. These filter aids are normally added to the suspension prior to filtration and thereby improve the permeability of the filter cake. It is also possible to put a layer of these aids onto the filer medium. 

---

Particle shape (for a given volume, the best shape for minimizing surface area and improving filterability is a sphere), and... 

The size distribution of the particles (with particles of a uniform size, there is increased voidage between the particles and a lower tortuosity, that is deviation from the linear path for the fluid flowing between the particles, making for improved filterability), and... 

J. W. Dobson, Jr. and P. D. Kayga. Magnesium peroxide breaker system improves filter cake removal. Petrol Eng Int, 68(10) 49-50, October 1995. 

Figure 3. Comparison of a standard DRUM sampler and IMPROVEd filters at Shenandoah National Park,...

Water washed, salt solution washed, cold solvent washed and sieved wheat starches did not improve filterability and final color of glucose syrups compared to those of well washed large granule wheat and com starches.561 When using a well washed, large granule wheat starch fraction, the ease of processing and final syrup quality are similar in most respects to that of corn syrups. 

Pasteur, N. and Georghiou, G.P., Improved filter paper test for detecting and quantifying increased esterase activity in organophosphorus-resistant mosquitoes (Diptera Culicidae), /. Econ. Entomoi, 82, 347,1989. 

Today, environmental air-quality is generally improving. Filters are installed in industrial facilities, cars are equipped with catalytic converters, and so forth. However, examination of the air we breathe in different places throughout the day shows that the air we breathe while driving in traffic is one of the worst microenvironments we can possibly encounter in everyday life. 

Elimination of turbidity, haze, emulsions Improved filterability of process liquor and finished product Reduced tendency to foam during evaporation and distillation Faster rate of settling during clarification... 

Advanced approaches to searching are on the horizon— to give some examples improved filtering of search results based on user profile or user history, automated analysis of document collection, and visual and graphical presentation of search results. Many of these approaches are still very experimental and not widely used because they may require some computer or network reconfiguration. This may act as a barrier because the reader has to decide to invest time and energy, and perhaps some money, Bovenschulte said. 

There are some commercially available electrospinning processes, such as the Nanospider electrospun nanofibres, which can provide thin coatings on traditional filtration substrates and enhance the filtration performance of these materials many fold. This technology can yield nanofibres with a narrow diameter distribution and distinct diameter size that can be used to optimise the filtration behaviour of the filter substrates for many applications, where particle retention efficiency is a critical requirement. These suhmicron fibres can significantly improve the air filtration efficiency of a variety of media and filters. The submicron fibres provide improved filter efficiency in the interception and inertial impaction regimes. ... 

A method of improving filter efficiency is to use compounds that can be mixed with the sludge to improve its filterability. Filter aids were also described earlier. The disadvantage of filter aids is that the quantity of sludge will increase. Tlie advisability of usmg filter aids is strongly dependent on die local cost, as well as the increase in filtration efficiency. 

Using larger pore size filters, however, has a greater effect on HEC fluid-loss characteristics than on those of HPG. HEC passed without restriction through a 0.22 pm filter after only mild degradation. This is similar to the results of improved filterability after improved mixing and hydration experiments described earlier in this chapter. On the other hand HPG fluid-loss characteristics did not show marked improvement until significant Mw reduction had occurred. Results are shown in Table 5. 

Wang et al. have recently repeated the calculation for the 24-mode pyrazine model employing an improved filtering technique, thereby reducing the number of trajectories required to obtain convergence by almost two orders of... 

USBM. 1981a. Improved filtering system for water sprays resists clogging. Technology News No. 20. 

---