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Utility bounds for nonconstant Q Δ T for heat‐integrated distillation sequence synthesis
Author(s) -
Westerberg A. W.,
Andrecovich M. J.
Publication year - 1985
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690310909
Subject(s) - reboiler , condenser (optics) , distillation , simple (philosophy) , constant (computer programming) , work (physics) , sequence (biology) , fractionating column , thermodynamics , diagram , mathematics , enthalpy , process integration , chemistry , computer science , process engineering , physics , chromatography , engineering , statistics , light source , philosophy , biochemistry , epistemology , optics , programming language
In earlier work the authors presented a simple method to synthesize heat‐integrated distillation sequences through the use of simple sketches on a diagram displaying temperature vs. enthalpy. Embedded in that work is the useful but in‐correct assumption that the reboiler/condenser heat loads and the temperature‐difference across the column are independent of the temperature (pressure) level at which the column is operated. This assumption of constancy is removed here, and it is shown how to calculate the minimum utility target using a small linear programming formulation. It is also shown how to use the results of this calculation to synthesize distillation sequences that approach the bound discovered. For the example problems solved, the minimum utility target calculated increases about 25 to 60% over that calculated assuming constant Q Δ T . The sequences synthesized based on this improved target are virtually the same as the constant Q Δ T method produces, suggesting that the earlier method is indeed a useful approach.