The feed system for a distillation process is shown in Figure P22.17(a). The feed to be distilled is an organic liquid stored in V-301 under a nitrogen blanket at a constant pressure of \(21 \mathrm{psi}\). The liquid is pumped through a pump, heat exchanger, and control valve to the distillation column. The pressure profile for the design flow of \(50 \mathrm{gpm}\) is shown in the diagram. Also shown are the elevations of the liquid level in the tank and the feed tray in the column. Using the pump characteristics shown in Figure P22.17(b), answer the following questions:

a. What is the maximum flowrate that can be pumped through this system assuming that the feed and destination pressures remain constant?

b. What would the vapor pressure of the liquid have to be at the entrance to the pump so that the pump would just cavitate at the design flow?

c. In order to design the heat exchanger, a maximum design pressure needs to be specified. It has been determined that the maximum pressure to which E-301 can be exposed occurs when the control valve fails closed while the pump continues to operate. What is this maximum pressure?

Figure 22.17 (a) and figure 22.17 (b)

Transcribed Image Text:

Liquid level in tank 8ft + 21 V-301 Frictional loss in suction line at design flow = 1 psi 60 Pressure in psi P-301 E-301 55 45 20 32 ft Flow at design conditions 50 gom Liquid density=866 kg/m Pressures shown in diagram are for design flowrate 2.0 ft of liquid 1.0 psi T-301