Large piston diaphragm pumps as a feasible alternative to multistage centrifugal slurry pumps

摘要

To transfer abrasive slurries through pipelines, generally two types of pumps are used: piston diaphragm pumps for low volumes of slurry against high pressures, and multistage centrifugal pumps for high volumes against low pressures.The discharge pressure of centrifugal slurry pumps is usually limited to 4 to 7 bars per pump. To achieve higher pressures, multiple centrifugal pumps are placed in series, either in a single pump station or in several pump stations, which are placed along the pipeline depending on the overall pressure required. For example, a total system pressure of 60 bars would require approximately eight pumps in series. The maximum flow capacity of these pumps can be close to 10,000 m~3/hr. The capacity of piston diaphragm pumps has historically been limited to approximately 750 m~3/h per unit and therefore multiple pumps placed in parallel are needed to match the capacity of large centrifugal pumps. Typically a high flow rate piston diaphragm pump station would therefore be equipped with five or six units operating in parallel.Using piston diaphragm pumps for slurry transfer has a number of potential advantages when compared to centrifugal pumps, resulting particularly from piston diaphragm pumps delivering constant flow independent of discharge pressure, and generally the need for only a single pump station. There are also potential benefits to be achieved in efficiency and availability, as well as spare parts consumption. A new size of piston diaphragm pump has become available which may prove to be a feasible alternative for multistage centrifugal pump systems. This new design offers a unit capacity of 1,200 m~3/h at a discharge pressure of up to 80 bars.This paper describes the result of a feasibility comparison, including CAPEX and OPEX costing between this new large piston diaphragm pump system and a multistage centrifugal pump system.