Condensate Polishing Unit – Ionberg
Ionberg > Condensate Polishing Unit
The Ionberg Condensate polishing is employed for purifying return steam condensate. This is essential for meeting the quality requirements of high pressure thermal cycles. It also minimizes consumption of make-up water. Condensate polishing is applied in places where the condensate is the major portion of the Boiler Feed Water. It is also applied if the risk of contamination of return condensate is persistent.
The Condensate Polishing removes following types of impurities:
Oxides of iron, copper and nickel are the major corrosive products. These products could be either in the form of particulate matter or in solution. They are removed by filtration of the condensate. Cartridge or precoat filters can be used for filtering these corrosive products.
Sometimes due to leakage of cooling water the impurities caused by dissolved salts arise. The use of ion exchange demineralizers these impurities can be cleared. For low-contamination levels mixed-bed ion exchangers are commonly used. Separate cation and anion exchangers can be used only when there is higher level of mineral contamination.
Working Principle Condensate Polishing Unit
In various manufacturing unit or plant steam is generated and released for generating electricity. The steam after loosing its heat condensate back into water. While condensing steam picks lot of impurities from the environment which should be completely removed before using condensate again. The polishing unit that is employed for this impurity is condensate polisher that employs ion exchange resin bed to remove the contaminants. After resin is exhausted it is regenerated.
On the basis of regeneration, condensate polishing systems can be of following types :
Mixed Bed External Regeneration
Mixed Bed In-situ Regeneration
Ion Exchanged Resins Used In Condensate Polishing
Following resins can be used either independently or in combinations in condensate polishing.
Strong acid cation (SAC) resins are used for softening, demineralization and dealkalization process. SAC resins are available in different crosslinkage. Resin with 8% crosslinkage is commonly used for electric utility condensate polishing applications where they remove corrosion products (crud) from the utility’s condensate.
Weak acid cation (WAC) resins are also used for dealkanization and demineralization processes. All cation that are held tightly to the resin are removed by WAC resin. Normally these resins remove resins remove only cations associated with alkalinity.
For various ion exchange demineralization processes, dealkanization, organic trap applications etc. SBA is used.
Weak base anion (WBA) resins do dual function that is it absorbs acid and functions as an ion exchanger. Only Strong acidic minerals are remove by them. However they allow the ions of carbonate/bicarbonate and silica to pass. It is due to this they are not used for demineralization.
Required Properties of Resins for Condensate Polishing
The resins used in condensate polishing should have following features:
It should have good physical strength in order to withstand vigorous cleaning. It is also necessary for the rigorous of hydraulic transfer during regeneration.
For effective separation of resin’s density should be precise.
To prevent any flow restriction during operation, size and kinetics of the resins is also important.