Page 202 - Chemical process engineering design and economics

184 Chapter 4

Table 4.8 Continued

3. Calculate the coolant exit temperature, fe, from Equation 4.7.6.

4. Calculate the logarithmic-mean temperature difference, (At)i_M. from Equation
4.7.5.

5. Calculate the logarithmic-mean temperature-difference correction factor, F,
from Equation 4.7.4.

6. Calculate the overall heat-transfer coefficient, U 0, from Equation 4.7.3.
7. Calculate the clean overall heat-transfer coefficient, Doc, from Equation 4.7.11.

8. Calculate the available fouling resistance, R OA, from Equation 4.7.10 and the
require fouling resistance, R OR, from Equation 4.7.9.

9. If ROA ^ ROR, the condenser will be adequate for the process.

NOMENCLATURE

English

A surface area
outside surface area of a tube
A 0
Cc capital cost per unit area

CM maintenance cost per unit area
Cp heat capacity at constant pressure
total cost
C T
C w cost of water per unit mass
D tube diameter
F logarithmic mean temperature correction factor or degrees of freedom
h heat transfer coefficient or enthalpy

k thermal conductivity
m mass flow rate
Q heat transfer rate

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