Heat-treated titanium balls for the mitigation of mineral fouling in heat exchangers

The present study investigated the feasibility of a physical water treatment (PWT) concept using heat-treated titanium balls for the mitigation of mineral fouling in heat exchangers. A concentric tube heat exchanger in a counter-flow set-up served as the test section, where three different velocities (i.e., 0.3, 0.5, 0.8 m/s) were used for the fouling tests. The results showed that for the PWT cases fouling resistances were 24-30% lower than those for the untreated cases, depending on the flow velocity and the electrical conductivity of water. The SEM photographs of the fouling deposits in the PWT cases revealed a soft form of scale that could easily be removed by the shear forces produced by the flow in the heat exchanger. Furthermore, the PWT case produced more particles in bulk water by approximately 35% than the untreated case, supporting the bulk precipitation hypothesis for the PWT.