Condensate Polishing Packages
Fossil-fueled (Demineralization) and nuclear power stations produce electricity with turbines powered with high pressure steam. A schematic representation of this steam circuit is shown in the picture figure below. After going through the turbine, the steam is condensed and recycled.
To avoid deposits on the turbine blades and corrosion in the steam circuit, the steam must be extremely pure. However, being continuously recycled, the condensate collects corrosion and erosion products from the boiler and pipe work, as shown in the figure. The contaminants in the condensate must have a concentration of a few µg/L (ppb) or less. Therefore, the condensate, in many power stations, is treated with ion exchange resins, ion exchange being the only process capable of achieving these low residual values.
Many new power stations are being built, particularly in emerging countries, so that the number of condensate polishing project has increased tremendously since the beginning of the 21st Century. Whilst ion exchange processes for water demineralization were mainly developed in Europe, the champions of condensate polishing design are largely American.
Electro-deionization Packages (EDI)
EDI products are used worldwide to produce ultrapure water systems in diverse applications, including power generation, pharmaceutical, semiconductor, petrochemical and laboratory pure water systems.AES offers custom build EDI systems in various capacities.
Electrodeionization (EDI) is a process by which an electric field is used to remove ions and polar species from an aqueous stream. EDI is used with reverse osmosis to replace ion exchange resin-mixed beds, which require onsite or offsite chemical regeneration.
By eliminating resin regenerating chemicals, EDI delivers significant economic and environmental benefits. EDI’s continuous process improves water quality by reducing water quality spikes and upsets.
Ion Exchange Packages
Ion Exchange Softening is the process of removing Calcium and Magnesium ions from water through cation exchange. This is typically used to reduce scaling tendency of water used for boiler feed, or to increase the lather effect of detergents, particularly in laundries
In this process, Calcium and Magnesium ions in solution are exchanged for sodium ions attached to a cationic resin. This resin is composed of R( SO3-) and in its charged form has a Sodium Ion (Na+) attached to it. When water is passed through this resin, the calcium and magnesium ions in the water displace the Sodium Ions, and adsorb onto the resin. Accordingly, the displaced Sodium ions are released into the water, to join with other ions replacing the calcium and magnesium to form new compounds.