Bench Scale Study of the Vacuum Freezing Ejector Absorption Process Page: 216

                                
4.7  THE STEADY STATE MELTER

Colt's procedure has been followed in formulating the equations for
estimating the size of the melter. The cross-sectional area of the ice
pack required to melt (condense) a given hourly mass rate of ice (vapor)
is found by dividing the required heat load by the product of an empiri-
cal heat transfer coefficient and the temperature driving force based on
the melter water outlet conditions. The heat transfer coefficient was
found by Colt to depend on the partial pressure of inerts in the melter
vapor.
Let
PM = total pressure on the melter, mm Hg
PA = partial pressure of inert gases, mm Hg
APL = pressure losses throughout the melter.
The temperature driving force, AT, is then taken as
AT = Tv - 32 ,   OF
where Tv is found as the equilibrium temperature at the pressure Pv,
where
Pv = PM - (PA + APL)
The heat load on the melter is found as the product of the vapor
rate and the difference between the inlet vapor enthalpy and the exit
water enthalpy at Tv. The inlet vapor enthalpy is as that of the ejector
exhaust steam.  If this total heat load is QI, then the melter cross-
sectional area is found to be

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