A steam-heated evaporator used to concentrate a feed stream by evaporating water is shown in the figure. The mass fraction of solute in the exit stream x is measured and controlled by adjusting the...

Extracted text: A steam-heated evaporator used to concentrate a feed stream by evaporating water is shown in the figure. The mass fraction of solute in the exit stream x is measured and controlled by adjusting the steam flow rate, S. Overhead D. 39 =0 Pressure Feed Steam, S - Condensate, S Product x, B a) What is the MV? cV? b) What are the possible disturbance variables (up to 4)? c) What is the sign of the process gain? Explain your reasoning. d) Should the control valve be fail-open or fail-close? Why? e) What should be the sign of Kc? Hoof