Tangential-spray system

Figure 372. Schematic representations of the product handling sections of three fluidized bed coaters. (a) Top spray, (b) tangential spray (rotary fluid bed coater), (c) bottom spray (Wurster coating system)...

Top spray. In the top spray system, the coating material is sprayed downward on to the fluid bed such that as the solid or porous particles move to the coating region, they become encapsulated. Top spray fluid-bed coaters produce higher yields of encapsulated particles than either bottom or tangential sprays. 

Another air pollution control system was designed for a fertiliser plant with wet cyclone, venturi scrubber, tangential spray tower and a packed tower with cold water and alkali solution—optional), and an induced draught fan discharging through a tall chimney. 

The reduction of the span value is of prime importance for the improvement of the spraying systems. The influence of the relative velocity between the threads and the ambient air due to the high tangential velocity had to be clarified within the... 

Various hollow-cone simplex atomizers (Fig. 2.1) have been developed for combustion applications, differing from each other mainly in the way that swirl is imparted to the issuing liquid jet. In these atomizers, swirl chambers may have conical slots, helical slots (or vanes), or tangential slots (or drilled holes). Using thin, removable swirl plates to cut or stamp the swirl chamber entry ports leads to economies of the atomization systems if spray uniformity is not a primary concern. Large simplex atomizers have found applications in utility boilers and industrial furnaces. Oil flow rates can be as high as 67 kg/min. 

Plant description. Two nearly identical 430-Mw(e), western, conventional pulverized-coal-utility boilers (referred to as plants A and D) were tested. Both units use tangentially fired burners and burn low-sulfur 200-mesh coal of heat content approximately 27 000 J/g. Both units are equipped with cold-side electrostatic precipitators (ESP) of design efficiency of 99.5% or greater, and a modern flue-gas desulfurization (FGD) system consisting of four verticle spray towers. 

The source term in the film momentum equation is considered to account for the interaction between the impinging spray and the pre-existent liquid film. This is particularly important in SCR systems, since the spray axis is alway angled with respect to the normal direction of the pipe and mixer walls. For this reason, the contribution to the film momentum can be decomposed into two components one normal to the wall surface and the other one tangential (, laying on the same plane of the face representing the wall. The former can be included in the film pressure equation, since it acts as an increase of pressure due to the canceling of the momentum in that direction. The latter, instead, is considered in the momentum equation as follows (S u) ... 

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