Centrifugal blower

Blast air, preheated to 650°C, is deflvered by centrifugal blowers through a refractory-lined busde main to the furnace. Zinc vapor from the reduced sinter is carried out with the furnace gases to a condenser fitted with mechanical rotors that are partly immersed in a shallow pool of molten lead. The lead flows countercurrenfly to the gas and is vigorously agitated by the rotors to create an intense shower of lead droplets throughout the condenser. 

The per pass ethylene conversion in the primary reactors is maintained at 20—30% in order to ensure catalyst selectivities of 70—80%. Vapor-phase oxidation inhibitors such as ethylene dichloride or vinyl chloride or other halogenated compounds are added to the inlet of the reactors in ppm concentrations to retard carbon dioxide formation (107,120,121). The process stream exiting the reactor may contain 1—3 mol % ethylene oxide. This hot effluent gas is then cooled ia a shell-and-tube heat exchanger to around 35—40°C by usiag the cold recycle reactor feed stream gas from the primary absorber. The cooled cmde product gas is then compressed ia a centrifugal blower before entering the primary absorber. 

Centrifugal blowers or turbines usually cannot generate enough pressure difference to overcome the added resistance of the recycle pipes. In addition, some components may condense out in the cooler, especially with high-boiling materials or at high pressures. These must be recycled by a liquid pump through an evaporator. This in turn makes them approach a steady-state slowly. ... 

Piston, or positive displacement pumps, are well known and much used. Centrifugal pumps are not as well understood. Consequently, piston pump performance is sometimes expected from centrifugal blowers. The main difference is that positive displacement or piston pumps generate flow, whereas centrifugal pumps produce pressure. With a piston pump, the pressure will increase to the level needed to maintain the flow set by the piston volume and stroking speed. In contrast, centrifugal pumps produce pressure the flow will increase until the pressure drop, produced by the flow, matches the pressure produced by the pump. 

Static head generated by a centrifugal blower depends on RPM alone for a given internal construction and a given set of dimensions. Pressure generated depends not only on RPM, but also on the density of the fluid. Flow depends on conditions outside the blower and so does the power needed. Therefore, blower performance should be characterized first by the head as a function of RPM thereafter, studies can be extended to describe the flow. 

Forced Draft Air introduced at the bottom of the tower is forced to the top by a centrifugal blower. 

Zentrifugal-abscheider, m. centrifugal separator. -geblUse, n. centrifugal blower or fan. -kraft, /. centrifugal force. -stoffmUhle, /. (Paper) centrifugal beater. 

Figure 12-41. Single impeller centrifugal blower. (Used by permission Elliott Company.)...

The affinity laws express the relationship between the head, capacity, speed, and size of centrifugal blowers and compressors. In general these relations can be applied to inlet volume conditions for good preliminary designs, but all final designs apply these laws to the actual discharge volumes from the impeller. ... 

Centrifugal Blowers These blowers have air or gases entering in the axial direction and being discharged in the radial direction. These blowers have three types of blades radial or straight blades, forward-curved blades, and backward-curved blades (Figs. 10-84 to 10-86). 

The blower is a steam or electricity driven centrifugal blower (Jacoby, 2004). It blows air into the sulfur burning furnace - and the furnace s offgas through the remainder of the acid plant. 0.3 to 0.5 bar pressure is required. 

The air supplied to each air dryer tray is first filtered to remove dust and then pressurized using a spark-proof centrifugal blower. The air for the dryer trays is passed through a steam-heated coil between the blower and the entrance to the dryer trays. After the air enters the trays, it flows upward through the meal at a nominal velocity of 14-21 m/minute, partially fluidizing the meal. The meal evapora-tively cools, and the released moismre is transferred to the ascending air. The warm, damp air exits the top of the meal layer and then exits the sidewall of the DC to a... 

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