Page 223 - Gas Adsorption Equilibria

4. Volumetric – Gravimetric Measurements 209

From measurements in working position (2) (Fig. 4.12), we get the numerical
value of the sorptive gas density

with

Here is the net volume of the adsorption chamber, i. e. its geometric
volume minus the volume of all fixed parts of the magnetic suspension and of
the other elements which permanently are included in the chamber as for
example wires of thermocouples, the basket for sorbent sample etc. Also
indicates the volume of the sorbent / sorbate sample which here again is
approximated by the helium volume, cp. Chaps. 2 and 3:

We also have the thermal equation of state (EOS) of the sorptive gas

and the mass balances

Here indicate the masses of components i = 1, 2 supplied to the
AC from the gas supply system and i = 1, 2) the masses of components
i = 1, 2 of the sorptive gas phase in equilibrium at pressure (p) and
temperature (T). The quantity (Z) in (4.44) is the so-called compressibility or
real gas factor of the sorptive gas. It is assumed to be a known function of
pressure, temperature and the composition i = 1, 2) of the gas mixture.
Adding eqs. (4.45) and inserting (4.40) and (4.41), we get in view of (4.43) for
the total gas mass initially supplied to the adsorption chamber