A $2000-$m$3$ vessel containing liquid methanol is being prepared for reuse.

After draining, it must be purged with nitrogen $(98\%$ nitrogen and $2\%$ oxygen$)$ and then purged with air to reach a fuel composition of $0\mathrm{.}1\%$ of the TLV$-$TWA $($Methanol TLVTWA$=200$ ppm$).$ Use sweep$-$through purging. Parameters are, pressure $1$atm, temperature $25$ C$,$ purging rates of $10$ m$3/$min$.$

a$.$ Establish the composition of the methanol vapor in the tank after draining.

b$.$ What is the target fuel composition for purging with nitrogen that contains $2\%$ oxygen?

c$.$ Calculate the amount of nitrogen required.

d$.$ Determine the quantity of sweep$-$through air required.