Versaflex® SI

Figure 1: Pilot plant cooling tower schematic

During preliminary pilot cooling tower testing using hard water as makeup, calcium hardness levels reached the break point and calcite precipitation began to occur. Upon reaching a level of 250 ppm silicon dioxide (SiO2) in the tower water, this caused apparent co-precipitation of silica. When using partially softened water as makeup to avoid potential calcite interference, however, no calcite or silica scale formation was observed throughout the test period.

Silica can exist in more than eleven different forms and reduce the accuracy of test scenarios for silica dispersants with laboratory-spiked sodium silicate.

Because of this, naturally occurring water from the city of Madera in Southern California, where silica/silicate scaling is generally problematic, was used as makeup to gradually concentrate silica in the evaporative cooling system under simulated conditions.

During the pilot cooling tower test, samples were taken every two days and tested for molybdatereactive silica levels as well as calcium and magnesium hardness. The results, shown in Figure 2, demonstrate the ability of our Versaflex® Si silica dispersant to significantly increase the solubility of silica in cooling water systems.

Figure 2: Results of pilot cooling tower test

Since pilot cooling tower tests indicated the superior effectiveness of our Versaflex® Si silica dispersant under simulated conditions, field trials were run to demonstrate its performance under real-world conditions.