Design of a Heat Exchanger You have been asked to perform a complete design of a suitable heat exchanger for handling the cooling process in a chemical process dealing with methanol cooling. It is desired to cool down 33.33 kg/s of methanol from 65oC to 30oC using cooling water at 25oC. The cooling water outlet temperature must not be higher than 40oC because of cooling system restrictions. It should be noted that pressure drops of 1.50 x 105 N/M2 for the process stream and 1 x 105 N/M2 for the cooling water are allowed. The total fouling resistance must be 5 x 10-4 (s.m2.K)/J. The physical properties of methanol are:
k = 0.21 J/(m.s.K)
ρ = 800 kg/m3
c = 2508 J/(kg.K)
Viscosity [kg/(m.s)]:
T(oC) 74 60 50 40 30
μ 0.00030 0.00036 0.00040 0.00047 0.000
It should be noted that any assumptions made in the calculations are to be explicitly stated and justifiable reasons to avoid penalty during assessment of individual report submissions.
Hints:
• Fix a tentative geometry and perform all standard calculations;
• Verify the adequacy of your proposed design in terms of operating parameters; and
• Modify the proposed design to make them compatible with the required allowances of parameters.