Consider a process in which a fluid is pumped from a storage tank through a heat exchanger, where it is heated and then pumped into another storage tank. The process flow diagram for this process is shown in Figure P22.15(a), and the pump and system curves are shown in Figure P22.15(b).

Figure 22.15 (a) and  Figure  P22.15 (b)

Currently, the system is operating with the control valve (cv-1) wide open, and the flow through the pump is measured at 100 gallons per minute (gpm). The elevations and pressures of both tanks are equal, and the pressure drop across the heat exchanger is \(5 \mathrm{psi}\), with the remaining 5 psi pressure drop occurring in the piping. It has been noted that the current velocity through the heat exchanger is very high and must be reduced by half. It is proposed to add a bypass line with a valve around the heat exchanger. The valve will be adjusted so that the flow through the heat exchanger is \(50 \%\) of the current flow. The control valve, cv-1, will remain wide open. For the proposed change, find the following:

a. The pressure drop across the heat exchanger.

b. The total flowrate of fluid passing through the pump.

c. Assume that all the resistance to heat transfer is on the process fluid side and that the temperature of the condensing steam remains constant. Determine the temprature of the fluid entering Tank 2.

Transcribed Image Text:

Tank 1 50 Pressure Drop, psi Temperature, "C Proposed Bypass cv-1 100 Tank 2 Condensate Steam 160C 160C Figure P22.15(a). Process Flow Diagram for Problem 22.15 30 25 20 15 10 10 5 D 0 20 40 60 80 100 120 Volumetric Flowrate, gpm Pump Curve Equation 4P(psi) =32.72[1-(vol. flow (gpm)/120)*1 10 140