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Characteristic of Boiler Feed Water

Water is always used to absorb the heat at any temperature than any other common inorganic substance. To form steam it evaporates 1600 times the expansion is very high to form steam at atmospheric pressure. The capability of the steam is to carry large quantity of heat. This characteristic of water makes it an ideal raw material for heating and of power generating process. All natural water contains varying amounts of dissolve and suspended matter and dissolved gases the amount of minerals dissolved varies from 30g to sea water to anything from 0.005 to 1500mg/l in fresh water supplies. the water used for boilers should be pure to avoid boiler problems. Good quality water must be used to generate steam. The composition of the feed water be such that the impurities can be concentrated any number of time without increasing the tolarence limit of the boiler if the feed water ,if there is lot of impurities it should be pre treated or the chemical treatment inside the boiler can reduce the impurities and the nature of impurities like hardness iron and silica are more concentrated than sodium salts. The whole thing depends on the boiler design .the capacity to remove the impurities to take the heat transfer pressure etc .A low pressure fire tube boiler can usually tolerate high feed water hardness with proper water treatment while all impurities must be removed from water used in some modern high pressure boilers. All depends on the working pressure of the boilers only relatively wide ranges can be given as to maximum levels of alkalis, salt, silica phosphates etc.