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CHEMCAD Introduction Fundamentals John Edwards, P&I Design Ltd January 2015

CHEMCAD Introduction Fundamentals John Edwards, P&I Design Ltd January 2015. www.chemstations.com. INTRODUCTION. Process simulation principles CHEMCAD modular structure CHEMCAD main features and interfaces Report format selection Modelling Procedure Convergence parameters

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CHEMCAD Introduction Fundamentals John Edwards, P&I Design Ltd January 2015

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  1. CHEMCAD Introduction Fundamentals John Edwards, P&I Design Ltd January 2015 www.chemstations.com

  2. INTRODUCTION • Process simulation principles • CHEMCAD modular structure • CHEMCAD main features and interfaces • Report format selection • Modelling Procedure • Convergence parameters • Standard conditions review • Units selection • Tutorial Case 2.01 • Draw flowsheets – palette use – zoom – copy - move • Stream calculator – bubble point – dew point • Heat exchanger utility option and area calculation • Controller to establish T&P design conditions • Sensitivity study to aid setting design conditions • Plot facilities saving, axes and export to Excel • Graphics – Fonts – lines – colours www.chemstations.com www.chemstations.net www.chemcad.co.uk

  3. PROCESS SIMULATION • Modelling requires engineering judgement • Estimates based on known practice used in initial simulations • Modelling enables the engineer to make mistakes faster • Simulation sometimes will give a result different to intuition > check • Plant problems should be reproducible in simulation • Always verify results with independent calculation>known practice www.chemstations.com www.chemstations.net www.chemcad.co.uk

  4. CRYOGENIC BATCH REACTOR OPTIMISATION SIMULATION PRINCIPLES Dynamic Based on real time or speed updynamics Realplant behaviour and equipment performance, retentiontimes Requires more information and more difficult to set up Ideal for troubleshooting, control loop tuning and real time study Steady State Based on direct substitution of value each iteration withspeed up principles Models plant behaviour usingcontinuous,time interval based, steady state estimates Requires least effort to set up and calibrate the flowsheet Ideal for economic analysis and process optimisation www.chemstations.com www.chemstations.net www.chemcad.co.uk

  5. SIMULATION PRINCIPLESINDIVIDUAL UNITS AND TOTAL PLANT Mass and Energy Balances Feeds Recycles Products SIMULATION SUITE Batch – Cycle Time, Volume Scale CHEMCAD SOFTWARE Continuous Steady State – Varying Throughput Continuous Dynamic – Start up, Shutdown, Feed Change , Composition Change Dynamic simulation is series of steady state cases www.chemstations.com www.chemcad.co.uk Demand driven simulation

  6. SIMULATION REALITY SIMULATION SUITE CHEMCAD SOFTWARE www.chemstations.com www.chemcad.co.uk

  7. CHEMCAD MODULES CHEMCAD Steady State CC-BATCH Batch Distillation FLASH Physical Properties Database CC-Dynamics Reactors-Columns Relief-Piping CC-THERM Heat Exchangers SAFETYNET Relief-Piping Dynamics www.chemstations.com www.chemstations.net www.chemcad.co.uk

  8. CHEMCAD MAIN FEATURES • Equipment Sizing and Rating • Pipe networks • Pump sizing • Ventilation systems • Relief devices • Packed & plate towers • Orifice plates • Control valves • Shell and tube heat exchanger • Air cooled heat exchanger • Plate heat exchangers • Pipe in pipe heat exchanger • Software and Component Data Bank • Component library > 2000 DIPPR • Phase Data from DECHEMA • Extensive Physical Property Data (PPD) • Regress user PPD and bips • Extensive K and H model capability • User Component specification • Export to Excel • Sensitivity and optimisation capability www.chemstations.com www.chemstations.net www.chemcad.co.uk

  9. CHEMCAD INTERFACES • Report Formats • Microsoft Word • Microsoft WordPad • Microsoft Excel • User Adaptations • User Components and Binary Interaction Parameters • VBA/VSTA • Simulation Control • Data Map with Excel • On-line Process Control & Optimisation • OPC-OLE for process control www.chemstations.com www.chemstations.net www.chemcad.co.uk

  10. REPORT FORMATS & FAST KEYS Reporting in Excel allows data manipulation Fast Keys F6 Units Converter F7 Calculator www.chemstations.com www.chemstations.net www.chemcad.co.uk

  11. MODELLING PROCEDURE Draw Flowsheet Set Engineering Units Select Convergence Select Components Consider Electrolytes Select Thermodynamics Run Wizard Specify T & P Adjust K Set Local K Set Global Phase SLV Adjust H Set Local H Specify Feed Streams Specify UnitOps Controllers & Convergence Data Map & Execution Rule Run Simulation Equipment Sizing Sensitivity Analyses Optimise SIMULATION SUITE CHEMCAD SOFTWARE Analyze Results TPxy-UnitOp Plots Sizing Reports Final PFD Report Component PPD Plots Consider Data Maps GUI Presentation www.chemstations.com www.chemstations.net www.pidesign.co.uk

  12. UNITS & STANDARD CONDITIONS TAB Select & Save Custom Profiles Load Profile Alt SI / ENGLISH www.chemstations.com www.chemstations.net www.chemcad.co.uk

  13. CONVERGENCE PARAMETERS www.chemstations.com www.chemstations.net www.chemcad.co.uk

  14. CONVERGENCE PARAMETERS DIRECT SUBSTITUTION Results from previous iteration used as starting value for the next iteration (Default) WEGSTEIN ACCELERATION Value replaced after 3iterations with speed up frequency (Default 4) DOMINANT EIGENVALUE (DEM) Value replaced after 4iterations with speed up frequency (Default 4) CALCULATION STEPS / ITERATIONS Number of iterations run before stopping if no convergence (Default 40) CONVERGENCE PARAMETERS How close value of property in iteration i+1 is to previous value in iteration i Tolerance 0.001 equivalent 10-3 absolute value > Flash tolerance by 1 to orders DAMPING FACTOR (WEGSTEIN - DEM) Specify value between 0 to 1 to stabilise calculation (Default 0.7) www.chemstations.com www.chemstations.net www.chemcad.co.uk

  15. CRYOGENIC BATCH REACTOR OPTIMISATION CASE 2.01 TUTORIAL Set recycle 20000 kg/h at -10C SAVE!!! www.chemstations.com www.chemstations.net www.chemcad.co.uk

  16. CRYOGENIC BATCH REACTOR OPTIMISATION THERMODYNAMIC K - VALUE TAB Set Global Phase V/L/S or V/L/L/S Override Global K UnitOp Local K Use V/L/L/S for extraction & azeotropes Check when Electrolytes Adjust K Set Local K Adjust H Set Local H www.chemstations.com www.chemstations.net www.chemcad.co.uk

  17. THERMODYNAMIC REVIEW CHEMCAD DATA BANK • Thermodynamics Enthalpy and Phases • Thermodynamic Selection Review • CHEMCAD Wizard • Refinery Thermodynamics • Component Data Bank Navigation • Library Equations • Physical Property Plots • TPxy Plots • Residue Curves www.chemstations.com www.chemstations.net www.chemcad.co.uk

  18. THERMODYNAMICSENTHALPY ISOBAR Section 4 page 58 www.chemstations.com www.chemstations.net www.chemcad.co.uk

  19. THERMODYNAMICsFLUID PHASES Section 4 page 61 www.chemstations.com www.chemstations.net www.chemcad.co.uk

  20. THERMODYNAMIC SELECTION CHEMCAD WIZARD COMP SINGLE MULTI CHEMICAL OTHER CHEM<13BAR OTHER SYSTEM SYSTEM HEAVY HC >70°C Data > 50% NRTL, Wilson UNIQUAC Data < 50% UNIFAC H=LATE (all) TEMP K=VAP H=LATE K=VAP H=SRK CHEM>13BAR K=SRK H=SRK SPECIAL METHODS AMINE K=AMINE H=AMINE SOUR K=SOUR H=SRK POLYMER K=UPLM H=LATE HCL/NH3 K=PPAQ H=SRK HTSL <70°C K=PSRK H=MIXH < 7 BAR > 7 BAR PRESS K=ESSO 90 to 200 °C H=LEE KESLER K=GS (P < 200 BAR) H=LEE KESLER K=PR H=PR www.chemstations.com www.chemstations.net www.chemcad.co.uk

  21. THERMODYNAMIC SELECTION PHASE BASED PHASE LIQUID GAS VAP ONLY LIQUID NAT GAS VLE SYSTEM SYSTEM LLE GAS EQUATION SOAVE REDLICH KWONG(SRK) BENEDICT WEBB RUBIN IDEAL VAPOR PRESSURE BIP MODEL LLE BIPS AZEOTROPE HYDROCARBON H=LATENT HEAT H=LEE KESLER H=LATENT HEAT NRTL (5 PAR) UNIQUAC (2 PAR) UNIFAC(INCREM) PENG ROBINSON GRAYSON STEED NO YES IDEAL NRTL (5 PAR) UNIQUAC (2 PAR) UNIFAC(INCREM) IDEAL VAP PRESS GAS EQUATION BIP MODEL H=LATENT HEAT H=LATENT HEAT H= SRK H=LEE KESLER www.chemstations.com www.chemstations.net www.chemcad.co.uk

  22. THERMODYNAMIC SELECTION POLAR NON-ELECTROLYTES Section 9 page 335 www.chemstations.com www.chemstations.net www.chemcad.co.uk

  23. REFINERY THERMODYNAMICS www.chemstations.com www.chemstations.net www.chemcad.co.uk

  24. REFINERY THERMODYNAMICS Grayson-Streed K model is primarily applicable to systems of non-polar hydrocarbons.   Good for modelling hydrocarbon units, depropanizers, debutanizers, or reformer systems. The approximate range of its applicability is as follows: Temperature Range                Pressure Range 0  to  800 F                         <  3000 psia (-18 to  430C)                        (< 20000 KPA) ESSO K model predicts K-values for heavy hydrocarbon materials effectively at pressures below 100 psia. Good for modeling vacuum towers. Average error for pure hydrocarbons is 8% for p* > 1 mmHg, and 30% for p* between 10E-6 and 1 mmHg according to the API Technical Data Book Vol 1 Lee-Kesler H model is good for hydrocarbon systems www.chemstations.com www.chemstations.net www.chemcad.co.uk

  25. CRYOGENIC BATCH REACTOR OPTIMISATION COMPONENT DATABASE LIBRARY EQUATIONS Thermophysical > Component Database > Physical Properties > Temperature Dependent Physical Properties > Library Equations www.chemstations.com www.chemstations.net www.chemcad.co.uk

  26. TPxy PLOTS & RESIDUE CURVES Nitrogen Ethanol Benzene Toluene Water NRTL V/L/L/S Latent Heat TPxy Residue Curve OHTC 500 Utility Option Controller Sensitivity Compressor Option www.chemstations.com www.chemstations.net www.chemcad.co.uk

  27. THERMODYNAMIC RESIDUE CURVES • Low boiling node • High boiling node • Saddle • Distillation boundary • Residue curves Section 9 page 339 www.chemstations.com www.chemstations.net www.chemcad.co.uk

  28. THERMODYNAMIC RESIDUE CURVES Section 9 page 339 Benzene Water Ethanol www.chemstations.com www.chemstations.net www.chemcad.co.uk

  29. TPxy PLOTS BUBBLE & DEW POINTs Section 9 page 337 Dew Point Bubble Point www.chemstations.com www.chemstations.net www.chemcad.co.uk

  30. CRYOGENIC BATCH REACTOR OPTIMISATION REFLUX RATIO METHODS • Ratio UnitOp • Heat exchanger utility option and area calculation • Flash UnitOp modes Inlet T&P and Set T&P • Controller to establish reflux ratio conditions • Data Map – Execution Rules - Excel Control • Plot Column Profiles www.chemstations.net www.chemcad.co.uk

  31. CRYOGENIC BATCH REACTOR OPTIMISATION CASE 2.02 RATIO CONTROL TUTORIAL www.chemstations.net www.chemcad.co.uk

  32. CRYOGENIC BATCH REACTOR OPTIMISATION CASE 2.02 RATIO CONTROL TUTORIAL www.chemstations.com www.chemstations.net www.chemcad.co.uk

  33. CRYOGENIC BATCH REACTOR OPTIMISATION CASE 2.03 COLUMN OVERHEADS TUTORIAL Process to separate Acetone from Toluene Temperature Bubble Point vf=0 Pressure 1.2 bar Nitrogen 2 kg/h Toluene 500 kg/h Benzene 500 kg/h HT Oil Option Dowtherm J or Syltherm XLT Hydrocarbon emission EPA regulation Check units CEiP page 11 In gases(volume basis) ppm V = mole fraction x 106 HC concentration 300 ppm V 0.0003 mole fraction Process Requirements Reflux flow (L) No sub-cooling, control ratio L/D Rundown (D) Cool for storage 35°C Cooling water Supply 15°C ∆T 10°C Heat Transfer Oil Supply -30°C(min) ∆T 5°C www.chemstations.net www.chemcad.co.uk

  34. CRYOGENIC BATCH REACTOR OPTIMISATION CASE 2.03 COLUMN OVERHEADS TUTORIAL Stream Calculator Unit Converter F6 Calculator F7 Gibbs Phase Rule 2 variables define state (CEiP p56) Bubble Point vf=0 (CEiP p57) Dew Point vf=1 Total Flow Basis Must select component mf or wf More unit options available Component Flow Total flow set by component flows! Reference stdL and stdV Heat Exchangers Utility Option ∆T approach 10°C OHTC CEiP page 247 Area calculated Flash UnitOp Condenser Mode Specify T and P Phase Separation Use Inlet T and P www.chemstations.net www.chemcad.co.uk

  35. CRYOGENIC BATCH REACTOR OPTIMISATION CASE 2.03 COLUMN OVERHEADS TUTORIAL www.chemstations.net www.chemcad.co.uk

  36. CRYOGENIC BATCH REACTOR OPTIMISATION DATA MAP EXCEL INTERFACE Execut ion Rules www.chemstations.net www.chemcad.co.uk

  37. CRYOGENIC BATCH REACTOR OPTIMISATION CUSTOMISED EXCEL REPORTS www.chemstations.net www.chemcad.co.uk

  38. CRYOGENIC BATCH REACTOR OPTIMISATION COLUMN PROFILES www.chemstations.net www.chemcad.co.uk

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