Ion Exchange Equipment Information
Ion exchange equipment is used to adjust the ionic content of potable and industrial process water. Water to be treated flows through a tank filled with an ion exchange resin. As the water flows through the resin it exchanges ions with similarly charged resins in the tank. The resin exchanges metallic ions such as calcium and magnesium with sodium ions. The result is a replacement of ions from the water with ions from the resin. Because this is an exchange of ions the resin has a fixed life before replacement.
Ionic impurities can seriously affect the reliability and operating efficiency of a boiler or process system. Buildup of scale or deposits formed by these impurities can cause flow restrictions, overheating and can lead to system failure. Hardness ions, such as calcium and magnesium, must be removed from the water supply before it can be used for a process system or as boiler feedwater. For high-pressure boiler feedwater systems and many process systems, almost all ions including carbon dioxide and silica must be removed.
Water softeners replace calcium, iron, magnesium and other metallic ions with sodium ions. They treat “hard water” and prevent the accumulation of scale in industrial boilers and pipes.
Deionization (DI) systems replace mineral content with oxygen and hydroxyl groups.
Most water softeners and deionization equipment include manual or automatic backwash systems. Automatic systems flush the exchange medium based on parameters such as time, volumetric operation, or chemical sensing. Because ion exchange equipment often runs discontinuously, continuous flow rate is an important specification. Efficient system designs account for low-flow conditions as well as periods of peak flow periods.
There are many applications for ion exchange equipment including recovery, removal, and ionic containment.
Some devices and systems are used to recover copper, nickel, cobalt and other precious or heavy metals from water-based or solvent-based mixtures.
Some equipment removes nitrates or process organic materials.
Sucrose processing facilities uses ion exchange equipment to soften feed streams and remove sugar from molasses.
Factories use ion exchange equipment to remove dissolved alkaline solids that can impede machine performance or reduce system life.
Ion exchange demineralization is a two-step process that involves treatment with both cation and anion exchange resins. The net effect is the removal of electrolytes and a yield of purified water.
Condensate polishing reduces particulate matter and dissolved contaminants in condensates from utility power plants.
Ion exchange equipment that captures trace amounts of radioactive materials or nuclides is also available.
Water softening and water purification systems are used to remove acids, alkalis, salts, or mixtures from anionic or slightly ionized substances. Ultra pure water is used in the fabrication of semiconductors and printed circuit boards. Residential ion exchange equipment is designed for single-family homes or high density facilities such as apartments or condominiums that supply water for drinking and bathing.
Ion exchange equipment is also used in industrial applications where ionic contamination can reduce quality and limit performance. Examples include automotive painting, automotive finishing, and electronic component assembly.
Selecting ion exchange equipment requires an understanding of market requirements. Products that are designed for food processing, medical, or sanitary applications are often regulated, certified, or approved by government or industry. Typically, these products meet high-purity standards for analytical testing. Standards for testing, operating, or installing ion exchange equipment are also available.
ASTM D4548 -- Standard test method for anion-cation balance of mixed bed ion-exchange resins
NSF 61 -- Standard sets health effects criteria for drinking ater system components