6- 206.31 (cont’d) c. d. When Tfdecreases, Pfdecreases. Decreasing temperature and increasing pressure both to increase the fractional condensation. When you decrease Tf, less compression is required to achieve a specified fractional condensation. A lower Tfrequires more refrigeration and therefore a greater refrigeration cost (Crefr). However, since less compression is required at the lower temperature, Ccompis lower at the lower temperature. Similarly, running at a higher Tflowers the refrigeration cost but raises the compression cost. The sum of the two costs is a minimum at an intermediate temperature.6.32 a. Basis : 120m min feed @ 1000 C(1273K), 35 atm3o. Use Kay’s rule. Cmpd.atmApply Newton's corrections for HHCO133.034.5COCH2224TK PTPccccorrccorrbgb gb gb gbg.....33212 8413208304 272 9190 7458−−′==+++=∑TyTKcici040 4130351330020 3042
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