Tutorial #4 - DOC by 4jV64J


									                                           CHEE 221
                                           Fall 2007

                         Tutorial 9: Energy Balances (No Reaction)

Tutorial Date: 9 November 2007

Question 1 (Problem 8.24 F&R)

Propane gas enters a continuous adiabatic heat exchanger at 40 °C and 250 kPa (abs) and exits at
240 °C. Superheated steam at 300 °C and 5.0 bar enters the exchanger flowing countercurrently
to the propane and exits as a saturated liquid at the same pressure.

   (a) Taking as a basis 100 mol of propane fed to the exchanger, draw and label a process
       flowchart. Include in your labelling the volume of propane fed (m3), the mass of steam
       fed (kg), and the volume of steam fed (m3).

   (b) Construct a inlet-outlet enthalpy table for the process, and calculate values for required
       specific enthalpies. It is convenient to use H2O (l, 0.01 °C) and C3H8 (g, 40 °C) as
       reference states. Why?

   (c) Use an energy balance to calculate the required mass feed rate of the steam. Then
       calculate the volumetric feed rate of the two streams (m3 steam fed/ m3propane fed).
       Assume ideal gas behaviour for the propane but not the steam and recall that the
       exchanger is adiabatic.

   (d) Calculate the heat transferred from the water to the propane (kJ/m3 propane fed). (Hint:
       Do an energy balance on either the water or the propane rather than on the entire heat

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