The modelling of gas-lift pumps: an application in the production of 123I

The purpose of this report is to investigate the possibility of using a gas-lift pump in the production of the radioisotope 123I at Harwell. The available literature on the uses of gas-lift pumps and on methods of predicting their performance is reviewed. It is concluded that most previous studies have been specific to a particular geometry or flow regime and do not usually allow, in a systematic way, for single-phase pressure losses in the suction pipe or return leg. It was found that these losses can be significant at higher flowrates. A mathematical model has been constructed using existing methods for calculating pressure losses. The predictions of this model compare well with measurements made on an experimental loop. Prediction of the performances of various geometries suggest that the flowrates required for the application in radioisotope production cannot be achieved. However, an improved design is suggested which merits further investigation. (author)