How to chose the best property prediction method for simulation ? Exercise 2 How to chose the best property prediction method for simulation ? 11/23/2018 054402 Design & Analysis II
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.). 11/23/2018 054402 Design & Analysis II
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. 11/23/2018 054402 Design & Analysis II
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. 11/23/2018 054402 Design & Analysis II
Issues in Selection of the Appropriate Thermodynamics Package Nature of mixture (e.g., hydrocarbon, polar, electrolyte, etc.) Pressure and temperature range Availability of data. 11/23/2018 054402 Design & Analysis II
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 11/23/2018 054402 Design & Analysis II
Eric Carlson’s Recommendations Figure 1 Non-electrolyte See Figure 2 E? Polar Electrolyte Electrolyte NRTL Or Pizer Real Peng-Robinson, Redlich-Kwong-Soave, Lee-Kesler-Plocker All Non-polar R? Chao-Seader, Grayson-Streed or Braun K-10 Polarity Pseudo & Real Real or pseudocomponents P? R? P? Pressure Vacuum Braun K-10 or ideal E? Electrolytes 11/23/2018 054402 Design & Analysis II
Figure 2 LL? ij? P? LL? ij? Yes NRTL, UNIQUAC and their variances Yes WILSON, NRTL, UNIQUAC and their variances ij? (See also Figure 3) P < 10 bar No Yes No UNIFAC LLE P? LL? Polar Non-electrolytes P > 10 bar No UNIFAC and its extensions Schwartentruber-Renon PR or SRK with WS PR or SRK with MHV2 LL? Yes Liquid/Liquid ij? P? Pressure No PSRK PR or SRK with MHV2 ij? Interaction Parameters Available 11/23/2018 054402 Design & Analysis II
Figure 3 DP? Wilson, NRTL, UNIQUAC, or UNIFAC with special EOS for Hexamers Figure 3 Hexamers DP? Yes Wilson, NRTL, UNIQUAC, UNIFAC with Hayden O’Connell or Northnagel EOS Dimers VAP? Wilson NRTL UNIQUAC UNIFAC Wilson, NRTL, UNIQUAC, or UNIFAC* with ideal Gas or RK EOS No VAP? Vapor Phase Association UNIFAC* and its Extensions DP? Degrees of Polymerizatiom 11/23/2018 054402 Design & Analysis II
Bob Seader’s Recommendations 11/23/2018 054402 Design & Analysis II
Bob Seader’s Recommendations Yes Figure 4 PSRK HC? Hydrocarbons PC? Yes LG? Light gases No E? Electrolyte See Figure 5 Yes LG? Yes PC? Organic Polar Compound See Figure 6 No PC? HC? No See Figure 5 No Yes Modified NRTL E? No Special: e.g., Sour Water (NH3, CO2, H2S, H2O) Aqueous amine solution with CO2 and H2S 11/23/2018 054402 Design & Analysis II
Figure 5 P? T? BP? Critical PR Cryogenic Narrow or wide Non-Critical PR, BWRS T? HC and/ or LG Non- Cryogenic BP? SRK, PR Very wide BP? Boiling point range of compound LKP T? Temperature region P? Pressure region 11/23/2018 054402 Design & Analysis II
Figure 6 PPS? BIP? Yes NRTL, UNIQUAC Available No PC with HC Wilson Not Available BIP? Binary Interaction Parameters UNIFAC PPS? Possible Phase Splitting 11/23/2018 054402 Design & Analysis II
Hyprotech Recommendations 11/23/2018 054402 Design & Analysis II
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 11/23/2018 054402 Design & Analysis II
Eric Carlson’s Recommendations for 1-Propanol ,H2O mixture Figure 1 Non-electrolyte See Figure 2 E? Polar Polarity Real or pseudocomponents R? P? Pressure E? Electrolytes 11/23/2018 054402 Design & Analysis II
Figure 2 LL? ij? P? LL? Yes WILSON, NRTL, UNIQUAC and their variances (See also Figure 3) P < 10 bar No No P? LL? Polar Non-electrolytes No UNIFAC and its extensions LL? Liquid/Liquid P? Pressure ij? Interaction Parameters Available 11/23/2018 054402 Design & Analysis II
Bob Seader’s Recommendations for 1-Propanol ,H2O mixture Figure 4 HC? Hydrocarbons LG? Light gases E? Electrolyte Yes LG? Yes PC? Organic Polar Compound See Figure 6 No PC? HC? 11/23/2018 054402 Design & Analysis II
Figure 6 PPS? BIP? Yes NRTL, UNIQUAC Available PC with HC Not Available BIP? Binary Interaction Parameters UNIFAC PPS? Possible Phase Splitting 11/23/2018 054402 Design & Analysis II
1-Propanol, H2O 11/23/2018 054402 Design & Analysis II
TXY macro for HYSYS 11/23/2018 054402 Design & Analysis II