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Exercise 2

Exercise 2. How to chose the best property prediction method for simulation ?. Importance of Selecting the Appropriate Prediction Method. Correct predictions of the physical properties of the mixture as a function of temperature and pressure.

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Exercise 2

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  1. Exercise 2 How to chose the best property prediction method for simulation ? 054402 Design & Analysis II

  2. Importance of Selecting the Appropriate Prediction Method • Correct predictions of the physical properties of the mixture as a function of temperature and pressure. • Each method is suitable only for particular types of components and limited to certain operating conditions. • Choosing the wrong method may lead to incorrect simulation results. • Particularly important for reliable computations associated with separation operations (distillation, LL extraction, etc.). 054402 Design & Analysis II

  3. Principle Steps in Selecting the Appropriate Thermodynamics Package Choosing the most suitable model/thermo method. Comparing the obtained predictions with data from the literature. Adding estimates for components that not available in the chosen thermo package. Can they be neglected? Generation of lab data if necessary to check the thermo model. 054402 Design & Analysis II

  4. Sources of Information • Publications and professional literature that deal with the process in question or with the components that participate in the process. • Simulator reference manual (HELP). • DATABANKS • Rules of thumb. 054402 Design & Analysis II

  5. Issues in Selection of the Appropriate Thermodynamics Package • Nature of mixture (e.g., hydrocarbon, polar, electrolyte, etc.) • Pressure and temperature range • Availability of data. 054402 Design & Analysis II

  6. Recommendations for the Selection of the Appropriate Thermodynamics Package Eric Carlson, “Don’t gamble with physical properties for simulations,” Chem. Eng. Prog. October 1996, 35-46 Prof J.D. (Bob) Seader, University of Utah Hyprotech Recommendations 054402 Design & Analysis II

  7. Non-electrolyte Polar Electrolyte Real All Non-polar Pseudo & Real Vacuum Eric Carlson’s Recommendations Figure 1 See Figure 2 E? Electrolyte NRTL Or Pizer Peng-Robinson, Redlich-Kwong-Soave, Lee-Kesler-Plocker R? Chao-Seader, Grayson-Streed or Braun K-10 Polarity Real or pseudocomponents P? R? P? Pressure Braun K-10 or ideal E? Electrolytes 054402 Design & Analysis II

  8. Yes NRTL, UNIQUAC and their variances Yes P < 10 bar No (See also Figure 3) Yes No Polar Non-electrolytes No Yes P > 10 bar No Figure 2 LL? WILSON, NRTL, UNIQUAC and their variances ij? UNIFAC LLE P? LL? UNIFAC and its extensions Schwartentruber-Renon PR or SRK with WS PR or SRK with MHV2 LL? Liquid/Liquid ij? P? Pressure PSRK PR or SRK with MHV2 ij? Interaction Parameters Available 054402 Design & Analysis II

  9. Hexamers Yes Dimers Wilson NRTL UNIQUAC UNIFAC No Wilson, NRTL, UNIQUAC, or UNIFAC with special EOS for Hexamers Figure 3 DP? Wilson, NRTL, UNIQUAC, UNIFAC with Hayden O’Connell or Northnagel EOS VAP? Wilson, NRTL, UNIQUAC, or UNIFAC* with ideal Gas or RK EOS VAP? Vapor Phase Association UNIFAC* and its Extensions DP? Degrees of Polymerizatiom 054402 Design & Analysis II

  10. Bob Seader’s Recommendations 054402 Design & Analysis II

  11. Yes Yes No Yes Yes No No Yes No No Bob Seader’s Recommendations Figure 4 PSRK HC? Hydrocarbons PC? LG? Light gases E? Electrolyte See Figure 5 LG? PC? Organic Polar Compound See Figure 6 PC? HC? See Figure 5 Modified NRTL E? Special: e.g., Sour Water (NH3, CO2, H2S, H2O) Aqueous amine solution with CO2 and H2S 054402 Design & Analysis II

  12. Critical Cryogenic Narrow or wide Non-Critical HC and/ or LG Non- Cryogenic Very wide Figure 5 PR P? PR, BWRS T? BP? SRK, PR BP? Boiling point range of compound LKP T? Temperature region P? Pressure region 054402 Design & Analysis II

  13. Yes Available No PC with HC Not Available Figure 6 NRTL, UNIQUAC PPS? BIP? Wilson BIP? Binary Interaction Parameters UNIFAC PPS? Possible Phase Splitting 054402 Design & Analysis II

  14. Hyprotech Recommendations 054402 Design & Analysis II

  15. Example • Find the best thermodynamic package for 1-Propanol , H2O mixture. Eric Carlson, “Don’t gamble with physical properties for simulations,” Chem. Eng. Prog. October 1996, 35-46 Prof J.D. (Bob) Seader, University of Utah 054402 Design & Analysis II

  16. Non-electrolyte Polar Eric Carlson’s Recommendationsfor 1-Propanol ,H2O mixture Figure 1 See Figure 2 E? Polarity Real or pseudocomponents R? P? Pressure E? Electrolytes 054402 Design & Analysis II

  17. Yes P < 10 bar No (See also Figure 3) No Polar Non-electrolytes No Figure 2 LL? WILSON, NRTL, UNIQUAC and their variances ij? P? LL? UNIFAC and its extensions LL? Liquid/Liquid P? Pressure ij? Interaction Parameters Available 054402 Design & Analysis II

  18. Yes Yes No Bob Seader’s Recommendationsfor 1-Propanol ,H2O mixture Figure 4 HC? Hydrocarbons LG? Light gases E? Electrolyte LG? PC? Organic Polar Compound See Figure 6 PC? HC? 054402 Design & Analysis II

  19. Yes Available PC with HC Not Available Figure 6 NRTL, UNIQUAC PPS? BIP? BIP? Binary Interaction Parameters UNIFAC PPS? Possible Phase Splitting 054402 Design & Analysis II

  20. 1-Propanol, H2O 054402 Design & Analysis II

  21. TXY macro for HYSYS 054402 Design & Analysis II

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