You must specify a pump to take an organic stream from a distillation reboiler to a storage tank. The liquid has a viscosity of $5 \mathrm{cP}$, an $\mathrm{SG}$ of 0.78 , and a vapor pressure of $150 \mathrm{mmHg}$. The pressure in the storage tank is $35 \mathrm{psig}$, and the inlet to the tank is located $75 \mathrm{ft}$ above the reboiler, which is at a pressure of 25 psig. The pipeline in which the pump is to be located is $2 \frac{1}{2} \mathrm{in}$. sch 40, $175 \mathrm{ft}$ long, and there will be two flanged elbows and a globe valve in each of the pump suction and discharge lines. The pump must deliver a flow rate of $200 \mathrm{gpm}$. If the pump you use has the same characteristics as that illustrated in Figure 8.2, determine:

Figure 8.2

(a) The proper impeller diameter to use with this pump

(b) The required head that the pump must deliver

(c) The actual head that the pump will develop

(d) The horsepower rating of the motor required to drive the pump

(e) The maximum distance above the reboiler that the pump can be located without cavitating

Transcribed Image Text:

Size 2 3 R & C 1% in. Pedestal 3500 rpm 4' minimum NPSH 400 Impeller dia. 300 200 8% in 8% in 7% in 7% in 6% in. 6% in. I Total head feet 100 50 MISSION VALVE AND PUMP COM Semi-open impeller Dia. 6%-8% in. Eye area 9.8 in. Curve 8 S1 20 ft Max. sphere 1% in. Maximum normal capacity for slurries and abrasive fluids 7ft 30% 10ft. 140% 15 ft 145% 50% 50 50 40HP 15 HP 20 HP 30 HP1 25 HP 25ft, 50% 45% 60 HP 50 HP 400 40% 500 600 700 Capacity-U.S. gallons per minute 100 200 300