PL02 - Cavitation sensing and optimization in Rotary Positive Displacement Pumps for transfer duties

Abstract

Pumps used in terminal transfer duties have a unique set of demands placed on them. They must be able to accomplish all of the following reliably and consistently: ? Transfer as fast as piping network allows (minimize operation time & demurrage charges) ? Unload as much fluid as possible (tank stripping) ? Handle varying suction and fluid conditions including vary viscosities, densities and vapor pressures ? Transfer to various locations within their facility ? Clear bottoms/residuals without pump damage Increasingly pumps with variable speed drives (VFD) are employed to allow the transfer rate to be varied according to the fluid and tank conditions as these vary. While VFDs offer the possibility of achieving optimum transfer rates, the difficulty presented is determining the optimum speed for reliable pump operation at each fluid condition. Depending on the type of pump utilized several different sensor schemes have been employed to accomplish this. The challenge has been to develop scheme which has wide applicability and reliability with different fluid types. This paper will discuss the unique constraints around transfer service and the types of pumps utilized together with a summary of the range of application for each type.