GB490022A - Treatment of boiler feed water, particularly for the removal of carbon dioxide - Google Patents

Abstract

<PICT:0490022/III/1> A method of treating boiler feed-water, which has been softened by means of a base exchange material, comprises introducing into the water an acid substance sufficient to reduce substantially the alkalinity of the water and thereafter subjecting the water at an elevated temperature to reduce pressure, whereby bicarbonates are decomposed and carbon dioxide is removed. The temperature to which the water is raised is preferably about 95 DEG C. In the construction shown, boiler feed water that has been softened is passed into the apparatus by pipe F1 and mixes with a small amount of an aqueous solution of sodium hydrogen sulphate supplied from a container S. The water passes through a coil E and through a pipe F which receives steam from a pipe O so as to raise the temperature to about 200 DEG F. as indicated by the thermometer R. The water is sprayed into a chamber A which is provided with baffles C and is connected through a pipe D and a pipe G to a vacuum pump H. The carbon dioxide and water vapour are thus removed from the water which is collected in a tank N by means of a pump J connected to the outlet of the chamber A. Heat is given up by the gas and vapour to the coil E. Instead of the continuous process described above the feed water may be treated in batches, each batch being treated in a vat with sodium hydrogen sulphate in solution sufficient to neutralize about 95 per cent of the total alkalinity, and the treated water then passing to the coil E.