A set-covering approach to minimize the variety of standard chemical process pumps in equipment pools

Abstract

A decision framework is presented to minimize the number of distinct ISO 2858 compliant standard chemical process pumps in an equipment pool. Two model variants are introduced: (i) the set cover problem to find the minimum number of ISO-sizes required to meet a given set of specifications, and (ii) the maximum coverage problem to investigate the trade-off between application coverage and equipment variety in the pump pool. A case study is carried out in cooperation with Evonik Operations GmbH applying the framework to a real-world data set; the results of which suggest significant potential to rationalize pumping equipment variety. Numerically, the decision model(s) were found tractable and thus readily applicable for industrial scale analyses. By including a model of centrifugal pump operating ranges taken from a dimensioning tool developed at German chemical industry association VCI, we eliminate the need to integrate further simulation software and minimize equipment-data requirements.