A Survey of Modern Centrifugal Pump Practice for Oilfield and Oil Refinery Services

Abstract

During the last thirty years there has been a manifold increase in the demand for centrifugal pumps for oilfield and oil refinery service, an increase in which British engineers have played a worthy part. With traditional British reticence little has been said of the achievements of British oil companies and British pump manufacturers in this field of activity, and the author has written this paper with the object of correcting the omission. In the field of oil transportation over long distances, for instance, the influence of British practice is to be seen in many oilfields throughout the world. Within the refinery considerable strides have been made, particularly in solving the difficult problem of handling unstable hydrocarbon liquids under high suction pressures. Hot oil pump practice is now more or less established, and in this development the greater share of credit is due to American pump manufacturers. These developments are dealt with at some length in the appropriate section of the paper. Another point which calls for comment here is the introduction of a new term, for the characteristic of flow into the impeller eye, which is used in section 3 of the paper. When dealing with hydrocarbon liquids under saturation pressure and temperature conditions, the so-called “suction performance” of a centrifugal pump becomes extremely important. As a description of this most important characteristic of a pump the use of the phrase “suction performance” is misleading, and it has led to much confusion of thought. An attempt has been made to reduce the possibility of further confusion by coining a new phrase based on the analogy of similar characteristics encountered in electrical engineering. Throughout the paper, therefore, the pump characteristic relating to flow into the impeller eye has been described as the characteristic of “flow inductance”. The paper would not be complete without an attempt to assess the future trend. There will probably be a much greater tendency towards electrification of main-line pumping plant. A further increase in operating temperatures and pressures will, no doubt, lead to many fundamental changes in the design of pumping plant for use inside the refinery. As an example, it is suggested that for some difficult duties it may be necessary to adopt pump designs in which stuffing boxes are avoided altogether. Finally, it is probable that refinery technologists will tend more and more to adopt chemical processes and chemical engineering practice, so introducing new problems for the pump designer.