chapter  5
24 Pages

Scale and Deposit Control Polymers for Industrial Water Treatment

The accumulation of unwanted deposits on equipment surfaces is a phenomenon that occurs in virtually all processes in which untreated water is heated. The deposits commonly encountered may be categorized into the following ve groups: (a) mineral scales (e.g. CaCO3, CaSO4 ⋅2H2O, BaSO4, Ca3(PO4)2, CaF2, SiO2), (b) suspended matter (e.g. mud or silt), (c) corrosion products (i.e., Fe2O3, Fe3O4, ZnO, CuO), (d) microbiological, and (e) metal-inhibitor salts. The deposition of these materials, especially on heat exchanger surfaces in cooling, boiler, geothermal, and distillation systems, can cause a number of operational problems such as plugging of pipes and pumps, inef cient water treatment chemical usage, increased operation costs, lost production due to system downtime, and ultimately heat exchanger failure. Greater water conservation has been a driver for operating industrial water systems at higher cycles of concentrations, thereby increasing the potential for deposit buildup on heat exchanger surfaces. Operating industrial water systems under stressed conditions demands a better understanding of system (feed and recirculating) water chemistry as well as the development of new and innovative agents for controlling scale/deposit, corrosion, and biofouling.