Question

Estimate the fugacity of pure water at 100 degrees Fahrenheit and 10,000 psia. Assume that the specific volume of liquid water at that temperature is 0.01613 ft3/lbm, independent of pressure.

Answer 1

DATA:

T=100 degrees F

change to abs

T = 100+459.67 R=559.67 R

Use R in english units

R= universal gas constant=10.73 psi ft3/lb mol oR

P= 10000 or 10^5 psia

Vm=0.01613 ft3/lbm

for a pure liquid:

f(l)=f(sat) exp[Vm(p-psat)/RT]

Where, fsat=fugacity of saturated vapours

so

use Psat for water i.e.

vapour pressure of pure water =0.9493 psia

then

F(water)=0.9493 psia [exp (0.01613 ft3/lbm )* (10000-0.9493)psia/(10.73 ft3/lb mol R) *(559.67R)

Fugacity (water) = 0.9778 psia