Suspended solids agglomerators

Rake The purpose of the rake is twofold direct the settled solids to the blowdown and to control the character of the sludge bed. High rake speed results in a fluffier bed while low speed hinders the contact between newly-formed floe (agglomerated suspended solids) and the bed. Note that most inclined-plate clarifiers do not have this feature. 

Most suspended solids in water have a surface electrical charge that provides stability to the particles. This ionic charge is usually a negative (—) charge and requires the addition of metal salts or cationic (+) polymer coagulants to destabilize the particles and permit them to agglomerate or come together. 

Inclined plate clarification is a traditional separation technology that has been used for decades to remove suspended solids from a liquid stream in various types of systems including traditional precipitation [12]. In the semiconductor industry, the clarifier is commonly used in fluoride waste treatment systems where calcium fluoride precipitate is concentrated prior to dewatering in a press, or in assembly/test operations to separate silicon fines from backgrind operations. The clarifier will concentrate the solid phase of slurry like a UF, but unlike the UF or MF, the clarifier may require the addition of a chemical polymer to facilitate the agglomeration of the suspended solids so that they settle and concentrate. Polymer addition adds another level of complexity to the waste treatment system. The clarifier does not provide a physical barrier to prevent the transport of solids to downstream equipment, so it may be necessary to install a UF or MF downstream of the clarifier to capture extraneous particles or to protect the downstream equipment from clarifier upsets. 

As a result of the mechanical action of mixing tools, turbulent or high intensity mixers do create fast moving, aerated, particulate matter systems. Therefore, interparticle collision and coalescence take place in a very similar fashion to that in suspended solids agglomerators. The main difference between the two methods is that in mixers particle movement is caused by mechanical forces while in suspended solids agglomerators drag forces induced by a flow of gas are the principal reason for movement of the bed of particulate matter, coalescence of particles, and agglomeration. 

Although suspended solids agglomerators lend themselves easily to continuous granulation, many systems are designed for batch operation. In most... 

Batch suspended solids agglomerators While a large number of different industrial applications has been developed during the past two or three decades, batch operations has found the widest use in pharmaceutical processing (see... 

Batch suspended solids agglomerators allow accurate adjustment of residual moisture, even if the drying rate drops drastically at low liquid content, and result in better control of overall product quality. Therefore, outside pharmaceutical applications, their main use is for baby formulae, special food products such as powdered cocoa, tea and coffee, fruit juice extracts, egg and milk powder, etc., for detergents as well as other cleaning reagents and chemicals. 

Continuous suspended solids agglomerators Development of continuous fluidized bed granulators was triggered by the desire to increase the capacity per unit while maintaining product quality. From a process point of view the advantage of continuous operation is that stationary and optimized conditions do prevail. 

Table 15 is a partial list of materials processed in the Anhydro fluid bed agglomerator. It stands as an example for all suspended solids agglomerators. 

The major growth mechanisms in suspended solids agglomerators are layering and coalescence after collision of wetted particles with each other or of particulate solids with binder droplets. At the same time drying or cooling takes place to activate the permanent binding mechanism (solid bridges). Intensive contact of... 

The fust documented development of fertilizer granulation in suspended solids agglomerators was in the early 1960s using the spouted bed technique, and in 1970 Fisons Fertilizer Ltd, UK, introduced prilling , the granulation of fertilizers from a melt by solidification of droplets in a vertical cooling chamber. 

In the early 1950s another pressure agglomeration technique emerged as an alternative to the already conventional tumble agglomeration methods in mixers, drums, pans, and suspended solids granulators. This technology uses roller presses which can be easily adapted to a wide range of capacities and materials. 

Ziircher and Thiier (32), in a recent paper, examined the effects of suspended solids (kaolinite) on the weathering of a No. 2 fuel oil by GC and IR. They found that there was fractionation of the oil with alkylated benzenes and naphthalenes enriched in the water phase while aliphatic hydrocarbons (above MW 250) were adsorbed. They also found that with increased turbulence, oil droplets were agglomerated with suspended minerals. They observed the same fractionation pattern for a ground-water oil spill, despite the fact that the oil had been biochemically altered. 

II. Apparatus producing movement while keeping solid particulate matter suspended or loosely dispersed in a suitable fluid - suspended solids agglomeration (Sections 7.4.4 and 7.4.5). 

Utilization of the inclined-pan granulator in the fertilizer industry was first reported in Germany in 195 3 for the granulation of ordinary superphosphate and the first documented application of suspended-solids agglomerators was in the early 1960s using a spouted bed [B.48]. 

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