Q$1.$ Consider the feed section of the phthalic anhydride process given below. A single control valve is used to control the flow of the combined vaporized naphthalene and air streams, Stream $7.$ In this process it is important to regulate both the flowrate of Stream $7$ and the relative amounts of air and naphthalene in Stream $7.$ Does the current control scheme allow this type of regulation to occur? If not, devise a control scheme that will allow both these variables to be controlled independently.