4 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 0.1 bar gauge pressure. The minimum depth of liquid in the tank is 1 m. The distillation column operates at a pressure of 500 mmHg. 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, 200m long. The pipe run from the tank to the column contains the following valves and fittings: 20 standard radius 90 degree elbows, two gate valves to isolate the pump (operated fully open), an orifice plate, and a flow control valve. If the maximum flow rate required is 20,000 kg/hr, calculate the pump motor rating (power) needed. Take the pump efficiency as 70% and allow for a pressure drop of 0.5 bar across the control valve and a loss of 10 velocity heads across the orifice. Take the density of dichlorobenzene as 1300 kg/m and friction factor as 0.0029. Pressure Drop due to friction AP (K+8f + 2 where K is the number of velocity heads Pressure in bar at pump outlet column pressure + static head difference + system losses Pump work volume flow x pressure difference Pump motor rating pump work/efficiency Table 1. Number of velocity heads Fitting Number 90 Gate Valve Orifice Total K KTotal 0.7 0.15 10