properties of steam

Properties of Steam

In evaporator calculations, the properties of saturated steam are involved at every step. We shall find in Table 41.1 (Hugot page no. 1034):

(1) The boiling point " t " of water corresponding to each pressure

(2) The sensible heat "q "contained in water which has attained that temperature

(3) The latent heat or heat of vaporisation r of water, for this temperature, i.e. the quantity of heat units which must be supplied to the water to change it into and temperature given.vapour at the pressure

For the temperatures which are met with in evaporation work, these two quantities of heat, q and r, may be obtained with sufficient precision by the formulae of Regnault

q = t

r = 607 - 0.7t

λ = q + r = 607 + 0.3t

q = sensible heat supplied to unit weight of water to raise it from freezing point to toC expressed in Kcal/kg

r = latent heat of vaporisation of water at toC i.e. the quantity of heat to change unit weight of water into steam at the same temperature, in kcal/kg

λ = total heat to be supplied to unit weight of water, starting at 0°C (32°F), to change it to steam at t°, expressed in kcal/kg

Categories: Evaporation