1 The process shown in Figure P1.1 is a distillation column used to separate a binary mixture of methanol and water. It is desired to regulate the composition of methanol in both overhead and bottoms product streams: xD and xB respectively. Let us assume that the reflux flowrate L can be varied, but both overhead and bottoms product flowrates, respectively, D and B, are determined by the steady-state material balance F=D+B. The feedrate to the column F, as well as the feed temperature T, are known to vary. The steam supply pressure to the reboiler P is also known to vary; Q is the steam flowrate through the thermal siphon reboiler. (a) Identify the output, manipulated (i.e., control), and disturbance variables of this process. (b) Assume that feed temperature measurements are available, and that this information is used to adjust the steam flow into the reboller in order to control the bottoms product composition. What type of control system configuration is this? Will this be an effective way of regulating the value of xB ? Explain what control problems one might expect this control system configuration to suffer from. (c) If the steam supply pressure variations become too frequent, what control system configuration would you suggest to minimize the effect which such variations will have on the regulation of xB ? Sketch this configuration