Question

# 2. A hot two-phase stream from the outlet of a heat exchanger is flashed in a separator releasing gases from the top. The separator is maintained at 150°C and 200 kPa. The bottom stream from the separator goes to a pump which pumps it through a heat exchanger and then to a reactor and then to a separator that is maintained at 400 kPa and 120°C. Bottom of the first separator and feed nozzle of the 2nd separator are at 3 m above the ground while the pump is at the ground level. The heat exchanger and reactors are at 15 m and 10 m above the ground, respectively, and their outlet temperatures are 200°C and 125°C, respectively. Equivalent length of the entire system from the pump discharge to the 2nd separator including the heat exchanger and reactor is 300 m with D=0.2 m and f(friction factor) =0.03. Assume turbulent flow conditions. Assume that the frictional pressure drop in the pump suction line is negligible. Other data: Vapor pressure of the material in the bottom stream is given by: In P* = 10–5000/T when P* is in kPa and T is in K. Density of the stream at the 1s separator bottom till the 2nd separator inlet can be assumed to be 900 kg/m³ \text { Pump curve is given by: } \Delta P_{p=\infty}(k P a)=350-6 \dot{v}^{2} \text { where } \dot{v} \text { is flowrate in } m^{3} / m i n NPSHR of the pump is given by: NPSH,(kPa)=7+5v^2 where i is flowrate in m³/min a. What is the maximum suction flowrate to the pump? b. What is the maximum discharge flowrate of the pump assuming there is no control valve? c. A control valve is now installed for which it is determined that at a flow of 120 m³/h, the pressure drop through the valve is 24 kPa even when the control valve is fully open. What is the maximum flowrate possible in this system?  Fig: 1  Fig: 2  Fig: 3  Fig: 4  Fig: 5  Fig: 6  Fig: 7