Sponge Ball Cleaning for Scale Prevention in a Multi-Stage Flash Evaporation-Type Desalination Plant

Abstract

The application of sponge ball cleaning to prevention of scale in a multi-stage flash evaporation-type desalination plant was tried. Sponge ball cleaning is a mechanical tube cleaning method that has been put into practice in the surface condensers of thermal and nuclear power plants.
The scale prevention effect of sponge ball cleaning was investigated in a 100m3/d-capacity, 10-stage flash evaporation plant. It was found that the scale release rate by ball friction was inversely proportional to deposit thickness, and that the removal of scale was insufficient because of high scale deposit rate.
Sponge ball cleaning combined with pH control, in which 50 percent decarbonation of feed sea water was done by partial acid dosing, showed good effect in prevention of scaling and corrosion.