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Workshop Notes
Workshop 9.1 This is a design problem using shortcut methods. After providing an
exchanger specification (i.e., hot stream outlet temperature and an overall heat transfer
coefficient, both defined in the workshop description), the design is straightforward.
Workshop 9.2 The results of Workshop 9.1 are duplicated.
Workshop 9.3 As this is a simulation workshop it is necessary to change the spec-
ification of Workshop 9.1 to simulation and to insert the value of UA calculated by
Workshop 9.1. The hot stream specification must also be removed. The simulation
duplicates the results of Workshop 9.1.
Workshop 9.4 Use of the exchanger design from Workshop 9.1 but with cocurrent
flows results in poorer performance. The heat transferred in Workshop 9.3 is about
131,000 Btu/hr, compared to 99,000 Btu/hr in Workshop 9.4. The log mean temperature
difference for the two cases is 35.1 and 26.6 F, respectively, which explains the poorer
performance of Workshop 9.4.
Workshop 9.5 The solution is straightforward.
Workshop 9.6 The hot stream specification is taken from the solution of Workshop
9.5. The results are virtually identical to those of Workshop 9.5.
REFERENCES
Aspen Plus version 7.0, Heaters documentation.
Aspen Plus version 7.0, Help: EDR, Exchanger Configuration, Heatx Reference, and Model Reference.
Hewitt, G. F., Ed., Handbook of Heat Exchanger Design , Begell House, New York, 1992.
Nagle, W. M., Mean temperature differences in multipass heat exchangers, Ind. Eng. Chem. , 25, 604-609
(1933).
Perry,R.H.,andGreen,D.W., Perry's Chemical Engineers' Handbook on CD- ROM, 7th ed., McGraw-Hill,
New York, 1999, Table 11.2.
Underwood, A. J. V., The calculation of the mean temperature differences in multipass heat exchangers,
J. Inst. Pet. Technol. , 20, 145-158 (1934).
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