Vapor Fugacity Pure Systems

Recap Fugacity is our new definition for equilibrium With IG as a reference state Fugacity coefficient defines relationship to IG state

Consider a pure system Your book uses: IG P (P=0) as reference state Low P as ref state BUT This notation ONLY good for tabulated data

Vapor Fugacity From Steam Tables How do I get g from a steam table? In this notation, how would I get the reference g?

Vapor Fugacity for Steam Table Example Determine the fugacity and fugacity coefficient for Steam at 200oC and 10 bar

Vapor Fugacity for Steam Table Example- Step 1 Look up h and s at the stated T and P

Vapor Fugacity for Steam Table Example- Step 2 Look up h and s at the stated T and P Look up h and s at the stated T and the lowest P you can find (P=10 kPa)

Vapor Fugacity for Steam Table Example- Step 3 Look up h and s at the stated T and P Look up h and s at the ref state Calculate g and ref g

Vapor Fugacity for Steam Table Example- Step 4 Look up h and s at the stated T and P Look up h and s at the ref state Calculate g and ref g Plug and/or chug

Pure Vapor Fugacity from Correlation Tables When considering compressiblity (Z) gases correlate relative to their critical point Tr=T/Tc Pr=P/Pc

Pure Vapor Fugacity from Generalized Correlations Find the fugacity and fugacity coefficient of water using generalized correlations at 212oC and 10 bar Pc=220.48 bar Tc=647.3 K w=0.344

Pure Vapor Fugacity from Generalized Correlations - 2 Look up values Done Calculate reduced P and T

Pure Vapor Fugacity from Generalized Correlations - 3 Look up values Calculate reduced P and T Look up in table, interpolate if need be

Pure Vapor Fugacity from Generalized Correlations - 4 Look up values Done Calculate reduced P and T Look up in table, interpolate if need be Plug and chug

What about mixtures? No tables exist for mixtures EOS (later) –OR- Generalized Correlation tables

Summary Vapor fugacity of pure steam Find h and s at state Find h and s at ref state (10 kPa and same T) Calculate g and ref g Plug and chug Formula is NOT for phi (multiply by low P not system P for f Divide f by system P for phi

Summary Fugacity from correlation tables (pure and mixed) Find or calculate critical info Find reduced P and T Look up values in tables (may need to interpolate) Plug and chug Reminder: log not ln in Koretsky tables