P$1.$ Three tanks in series are used to preheat a multicomponent oil solution before it is fed to a distillation

column for separation as shown in Figure P$1.$ Each tank is initially filled with $1000$ kg of oil at $20\backslash$deg C$.$ Saturated

steam at a temperature of $250\backslash$deg Ccondenses within coils immersed in each tank. The oil is fed into the first

tank at the rate of $100$ kg$/$min and overflows into the second and the third tanks at the same flow rate. The

temperature of the oil fed to the first tank is $20\backslash$deg C$.$ The tanks are well mixed so that the temperature inside

the tanks is uniform, and the outlet stream temperature is the temperature within the tank. The heat

capacity, Cp$,$ of the oil is $2\mathrm{.}0$ KJ$/$kg$.$ For a particular tank, the rate at which heat is transferred to the oil from

the steam coil is given by the expression where UA$=10$ kJ$/$min$\backslash$deg C is the product of the heat transfer coefficient and the area of the coil for each tank,

T $=$ temperature of the oil in the tank in $,$ and Q$=$ rate of heat transferred in kJ$/$min$.$

The mass flow rate to each tank will remain at the same fixed value. Thus W $=$ W$1=$ W$2=$ W$3.$ The mass in

each tank will be assumed constant as the tank volume and oil density are assumed to be constant. Thus M

$=$ M$1=$ M$2=$ M$3.$

$*$ Develop the Data flow diagram of the process $($DFD$.$ See section $1\mathrm{.}4$ in the reference book$)*$