High speed centrifugal pumps

Figure 3-12. Single-stage, high speed (>5000 ft) centrifugal process pump. Pumps are high speed, gear driven, and especially suited for applications in light hydrocarbon liquid service. (Courtesy Sundstrand Fluid Handling, Inc.)...

The most reliable recycle reactors are those with a centrifugal pump, a fixed bed of catalyst, and a well-defined and forced flow path through the catalyst bed. Some of those shown on the two bottom rows in Jankowski s papers are of this type. From these, large diameter and/or high speed blowers are needed to generate high pressure increase and only small gaps can be tolerated between catalyst basket and blower, to minimize internal back flow. 

Figure 56.1 shows the cross-section of a typical end-suction centrifugal pump where the fluid to be pumped enters the suction inlet at the eye of the impeller. Due to the relatively high speed of rotation, the fluid collected within the impeller vanes is held captive because of the close tolerance between the front face of the impeller and the pump housing. 

Centrifugal pumps utilize one or more impellers rotating at high speed within a casing to provide centrifugal force to the FW and to convert this force into pressure. 

The nature of the power supply. If the pump is to be driven by an electric motor or internal combustion engine, a high-speed centrifugal or rotary pump will be... 

In this type of pump (Figure 8.19), the fluid is fed to the centre of a rotating impeller and is thrown outward by centrifugal action. As a result of the high speed of rotation the... 

The pressure developed by a centrifugal pump depends on the fluid density, the diameter of the pump impeller, the rotational speed of the impeller, and the volumetric flow rate through the pump (centrifugal pumps are not recommended for highly viscous fluids, so viscosity is not commonly an important variable). Furthermore, the pressure developed by the pump is commonly expressed as the pump head, which is the height of a column of the fluid in the pump that exerts the same pressure as the pump pressure. 

A Multi-stage centrifugal pump. B Single-stage high-speed centrifugal pump. 

A similar evaluation relevant to the comparison of efficiency and resulting energy costs with high speed centrifugal pumps, gives a clear indication in favour of the PDP. In a particular case of application, based on an energy price level of 0.12 DM/KWh, the break even point has been reached already after one and a half years. 

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