Processing filtration

This chapter deals with the basic air-handling processes filtration of particles and gaseous substances from the supply and recirculated air, air heating and cooling, heat-recovery processes, and humidification and dehumidification. It also describes fans and ductwork. 

Figure 4-77B. Porous sintered metal filter elements. By permission, Pall Process Filtration Co.

Pall Process Filtration Ceramic Candle Filter 1000°C (max.) 99.99% Supported both sides clay bonded silicon carbide filter... 

The electrostatic forces in many systems play a dominant role, such as the separation process (filtration) in wastewater treatment. 

Rotary Drum Vacuum Filter The underflow from the thickener is the feed to this filter. The filter concentrates the solids (predominately calcium sulfite), which then leave the filter in a cake form and are transferred to a cake repulp tank where they can be reslurried. The liquid generated from the filtering process (filtrate) is collected and pumped to the lime reactor vessel. 

When a cup of tea is poured through a tea strainer you are carrying out a filtering process. Filtration is a common separation technique used in chemistry laboratories throughout the world. It is used when a solid needs to be separated from a liquid. For example, sand can be separated from a mixture with water by filtering through filter paper as shown in Figure 2.13. 

Pinacci, P., Radaelli, M., Bottino, A., and Capannelli, G. 2004. Molasses purification by integrated membrane processes. Filtration (Coalville, United Kingdom), 4(2), 119-122. 

Filtration is the most straightforward, probably the oldest form of sugar liquor clarification process. Filtration is effected with plate and frame pressure-filters or some type of leaf pressure-filter such as Sweetland filters with stationary suspended circular leaves covered on both sides with filter cloth. A filter aid of some sort (diatomaceous earth, paper pulp, or kieselghur) is essential to the operation. The precipitated calcium carbonate serves as a filter aid in the carbonation process. The liquor is mixed with the filter aid and forced under pump pressure through the fabric, which retains the cake and allows the clear liquor to flow through. The retained sugar in the cake can be washed out with hot water. Filtration is no longer used as the sole means of clarification. The process is used for further clarification of the liquor from a carbonation or phosphatation process. 

In a 250-mL, two-necked flask flushed with nitrogen, 1.5 g of freshly prepared sodium amide (38 mmole) and 6.2 g of tetramethylphosphonium bromide (36 mmole) are suspended in 100 ml of tetrahydrofuran. The mixture is heated under reflux for at least 5 hours. The ammonia evolved is trapped in a scrubbing bottle containing 1 N H2SO4. Titration of the acid indicates that 36 mmole (100%) of NH3 are formed in the process. Filtration from the sodium bromide formed (3.2 g) and fractional distillation of the filtrate yields 2.9 g (90%), bp, 122°/760 torr. All isolation and purification procedures are also conducted under nitrogen, using glass apparatus with inert gas inlet cocks. 

Tap-water should be collected at the water processing (filtration/purification) plants just prior to discharge into the distribution system. If the water is to be collected from a residence, then the pipes should be flushed sufficiently (2 or 3 min) prior to sample collection. 

In approaching the initial selection of equipment, flows to be processed, filtrate clarity, and cake liquid, and solute contents must first be fixed. The product may... 

Alterations in one or more of the three renal processes (filtration, secretion, or reabsorption) secondary to reductions in functional nephron mass may have a dramatic effect on the pharmacokinetics of a drug. A reduction in glomerular filtration rate results in a decrease in renal drug clearance. For drugs that are extensively renally secreted (CLr >300 mL/min), the loss of filtration clearance (up to 120 mL/min) will have less of an impact than for those primarily dependent on GFR. 

Membrane Pore Diameter or Molecular Weight Cutoff. The value of membrane pore diameter will have a major influence on the permeation and separation characteristics for most process filtration applications. The intrinsic membrane permeability is related to the pore diameter for many microfiltration membranes whereas, for ultrafiltration membranes, it is typically indicative of the solute retention properties. Tables 8 and 9 provide typical permeability and retention data for many common MF and UF membranes, respectively.f t ... 

Suitable environmental conditions should be maintained by installation of effective air- extraction systems, with discharge points situated to avoid contamination of other products and processes. Filtration of other systems should be installed to retain dust The use of tablet and capsule dedusting devices is recommended. 

Despite the relative ineffectiveness for chemical disinfectants including iodine, in order to achieve the required 2-log inactivation of C. parvum, there are several applications that may incorporate its use in future designs. These designs are for personal water purification devices that incorporate a physical removal process (filtration) followed by the use of a chemical disinfectant. Iodine seems to be a popular choice, due to its relative stabihty and proven success against bacterial and viral contaminants. Iodine is used to impregnate the materials used in purification systems, such as a resin, or a physical removal system, such as a straw. The combination of physical and chemical processes does warrant further consideration to improve the achieved level of protection. 

Immobilized catalyst photoreactor systems permit the continuous use of the photocatalyst, eliminating the need for post-process filtration coupled with particle recovery and catalyst regeneration. Such reactors may display a number of drawbacks... 

New wine has a very high particle content, consisting of yeast lees and other grape debris. Clarity is achieved by gradual settling, followed by racking to eliminate the solids. Other, more rapid, processes (filtration and centrifugation) may also be used. 

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