Thermoeconomic evaluation of boiler feedwater heating and deaeration

Boiler feed water deaeration by direct steam contact heating is a common practice for removal of non condensable gases from boiler feed water which otherwise would cause corrosion of heat exchange surfaces and would lessen the corresponding overall heat transfer coefficients. There are many factors influencing the choise of deaeration temperature and optional subsequent feed water heating, such as type of fuel used, boiler design, stack temperature, type of industry (with or without steam turbine) and more. As one can imagine, the choice of optimal feed water heating is even more complicated when retrofitting an existing industry, since on the one hand there usually are additional constraints and obstacles and on the other one retrofit solution is tailor-made for each industry, which implies a big number of difficulties as well as a number of possible solutions to be carefully considered. Based on the concept mentioned above, results of simplified thermoeconomic analysis will be the source data for some considerations and simple solutions, which may be directly used by engineers when improving the feed water heating and deaeration system.