A vessel has a volume of $4$ m$3$ and contains air.

a$.$ Vacuum inerting is being used to bring the oxygen concentration to $1$ ppm$.$

Vacuum is available at $2\mathrm{.}5$ kPa absolute pressure. Find the number of vacuum

purge cycles and the amount of nitrogen needed if the temperature is $250$C$.$

b$.$ Pressure inerting is an alternate process. Pressurized nitrogen is available at $550$ kPa to achieve the same oxygen concentration in the same vessel as in a above.

Determine the cycles needed and the amount of nitrogen. Compare your values

to values from a$.$