Crude dichlorobenzene is pumped from a storage tank to a distillation column. The tank is blanketed with nitrogen

and the pressure above the liquid surface is held constant at $0\mathrm{.}1$ bar gauge pressure. The minimum depth of liquid in

the tank is $1$ m$.$ The distillation column operates at a pressure of $500$ mmHg $(500$ mm of mercury, absolute$).$ The feed

point to the column is $12$ m above the base of the tank. The tank and column are connected by a $50$ mm internal

diameter commercial steel pipe, $200$ m long. The pipe run from the tank to the column contains the following valves

and fittings: $20$ standard elbows; two gate valves to isolate the pump $($operated fully open$)$; an orifice plate and a flowcontrol valve. If the maximum flow$-$rate required is $20,000$ kg$/$h$,$ calculate the pump motor rating $($power$)$ needed.

Take the pump efficiency as $70$ per cent and allow for a pressure drop of $0\mathrm{.}5$ bar across the control valve and a loss of

$10$ velocity heads across the orifice. Density of the dichlorobenzene $1300$ kg$/$m$3$

$,$ viscosity $1\mathrm{.}4$ cp$.$