Aspen Physical Property System - Physical Property Models

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� User models for density and enthalpy. See User Models for Nonconventional Properties in Chapter 6 of Aspen Plus User Models, for details on writing the subroutines for these user models. Notation Most correlations for the calculation of coal properties require proximate, ultimate, and other analyses. These are converted to a dry, mineral-matterfree basis. Only the organic portion of the coal is considered. Moisture corrections are made for all analyses except hydrogen, according to the formula: Where: w = The value determined for weight fraction w d = The value on a dry basis = The moisture weight fraction For hydrogen, the formula includes a correction for free-moisture hydrogen: The mineral matter content is calculated using the modified Parr formula: The ash term corrects for water lost by decomposition of clays in the ash determination. The average water constitution of clays is assumed to be 11.2 percent. The sulfur term allows for loss in weight of pyritic sulfur when pyrite is burned to ferric oxide. The original Parr formula assumed that all sulfur is pyritic sulfur. This formula included sulfatic and organic sulfur in the mineralmatter calculation. When information regarding the forms of sulfur is available, use the modified Parr formula to give a better approximation of the percent of inorganic material present. Because chlorine is usually small for United States coals, you can omit chlorine from the calculation. Correct analyses from a dry basis to a dry, mineral-matter-free basis, using the formula: Where: �w d = Correction factor for other losses, such as the loss of carbon in carbonates and the loss of hydrogen present in the water constitution of clays 298 4 Nonconventional Solid Property Models
The oxygen and organic sulfur contents are usually calculated by difference as: Where: Cp = Heat capacity / (J/kgK) cp = Heat capacity / (cal/gC) h = Specific enthalpy �ch = Specific heat of combustion �fh = Specific heat of formation Ro = Mean-maximum relectance in oil T = Temperature/K t = Temperature/C w = Weight fraction � = Specific density Subscripts: A = Ash C = Carbon Cl = Chlorine FC = Fixed carbon H = Hydrogen H2O = Moisture MM = Mineral matter N = Nitrogen O = Oxygen So = Organic sulfur Sp = Pyritic sulfur St = Total sulfur S = Other sulfur VM = Volatile matter Superscripts: d = Dry basis 4 Nonconventional Solid Property Models 299
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Aspen Physical Property System Phys
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Contents Contents..................
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General Pure Component Solid Molar
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1 Introduction This manual describe
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Pure Component Temperature- Depende
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the Properties Parameters Pure-Comp
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2 Thermodynamic Property Models Thi
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Property Model Model Name Phase(s)P
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Property Model Model Name 2 Thermod
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Where: Parameter Name/Element 2 The
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critical temperature, the critical
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Where the ideal-gas contribution
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, where � For polar, associating
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Parameter Name/ Element 2 Thermodyn
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The denominator of equation 8 is gi
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V. V. De Leeuw and S. Watanasiri, "
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References M. Benedict, G. B. Webb,
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References L. Haar, J.S. Gallagher,
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Parameter Name/Element NTHDDH 0 †
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Gibbs free energy departure: The fo
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For a block copolymer, there is onl
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Copolymer PC-SAFT Dispersion Term T
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The association-site number of the
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Then I2(�) and I3(�) are comput
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A databank called PC-SAFT contains
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Parameter Name/Element PRKBV/1 k ij
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Predictive SRK (PSRK) This model us
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ka,ij kb,ij = = For best results, b
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J. Schwartzentruber and H. Renon, "
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Redlich-Kwong-Soave-MHV2 This equat
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‡ RKUC0, RKUC1, and RKUC2 are tre
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Parameter Name/ Element SRKLIJ/3 l
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Parameter Name/ Element Symbol Defa
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Association Equilibria Every associ
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and respectively. For the reactions
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R. W. Long, J. H. Hildebrand, and W
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Where the L, M, and N are parameter
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Alpha function Model name First Opt
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mi = Computed by equation 6 Equatio
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Parameter Name/Element 2 Thermodyna
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standard RKS alpha function, except
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These mixing rules are discussed se
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Where both Ai* and Am are calculate
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Like Huron and Vidal, the limiting
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Model Type Wilson Local composition
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Therefore, the simplified Pitzer eq
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Parameter Name/Element Symbol Defau
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Where: �i 2 Thermodynamic Propert
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The electrolyte NRTL model uses the
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Parameter Symbol No. of Name Elemen
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with Where: xi = Mole fraction of c
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It should be understood that equati
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The reference Gibbs energy is deter
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Where: j and k can be any species (
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The pure component dielectric const
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2 Thermodynamic Property Models 109
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�I *PDH = Pitzer-Debye-Hückel te
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Where: �i Vi = Activity coefficie
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Recommended cij Values for Differen
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Parameter Name/ Element 2 Thermodyn
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NRTL-SAC Reference States The NRTL-
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For an anionic component, we have M
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For a molecular segment, the activi
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Specifically, The long range intera
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where and are activity coefficients
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and Y+, are used to reflect the wid
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Parameter Name/ Element Symbol Defa
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Reference C.-C. Chen and Y. Song, "
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Parameter Name GMPTPS, GMPTP1, GMPT
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zi = Charge of ion i Subscripts c,
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For option code = 0 (default), the
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and for n-m electrolytes: 2 Thermod
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= 0.00979 Perform the necessary con
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Pitzer, K.S., J.R. Peterson, and L.
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A4,ij = gij / T + hij A5,ij = mij /
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Symmetric and Unsymmetric Electroly
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Parameter Symbol No. of Name Elemen
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Reference state for ionic component
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with 2 Thermodynamic Property Model
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G for these pairs is calculated the
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with 2 Thermodynamic Property Model
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Activity Coefficient Basis for Henr
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Where is the liquid Gibbs free ener
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Ionic components 2 Thermodynamic Pr
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the pure fused salts. Applying Eq.
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�k is the activity coefficient of
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References U. Weidlich and J. Gmehl
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ti' = �ij 2 Thermodynamic Propert
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Wagner Interaction Parameter The Wa
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References G.M. Wilson, J. Am. Chem
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Extended Antoine Equation Parameter
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IK-CAPE Vapor Pressure Equation The
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Harlacher and Braun, "A Four-Parame
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General Pure Component Heat of Vapo
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IK-CAPE Heat of Vaporization Equati
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Where: xp = Mole fraction of pseudo
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Parameter Name/Element VLBROC/1 V i
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Where: Vm l,t = Liquid volume per n
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Debye-Hückel Volume The Debye-Hüc
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DIPPR DIPPR equation 105 is the def
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Rackett The Rackett equation is: Wh
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Rackett/Campbell-Thodos Mixture Liq
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Zm RA Zi *,RA Vcm 2 Thermodynamic P
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General Pure Component Solid Molar
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Liquid Volume Quadratic Mixing Rule
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If THRSWT/6 is This equation is use
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Parameter Symbol Default MDS Lower
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General Pure Component Ideal Gas He
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(Other DIPPR equations may sometime
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General Pure Component Solid Heat C
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The expression for the liquid mole
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� Entropy: � Heat capacity: �
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Parameter Name † /Element CPIXPn/
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Option Codes for Electrolyte NRTL E
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Parameter Name Applicable Component
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For subcritical components: Hm l -H
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The vapor enthalpy is calculated fr
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Where: 2 Thermodynamic Property Mod
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Correlation algorithms for ionic sp
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Model Model name Phase(s) Pure Mixt
Page 249 and 250: Model Type Aspen Liquid Mixture Vis
Page 251 and 252: (Other DIPPR equations may sometime
Page 253 and 254: Parameter Symbol Default MDS Lower
Page 255 and 256: �i = Viscosity of component i (N-
Page 257 and 258: Parameter Name/Element 3 Transport
Page 259 and 260: Where: The Stockmayer or Lennard-Jo
Page 261 and 262: Where: Vcij = �ij = 0 (in almost
Page 263 and 264: Where: Vcij = �ij = 0 (in almost
Page 265 and 266: Jones-Dole Electrolyte Correction T
Page 267 and 268: Letsou-Stiel The Letsou-Stiel model
Page 269 and 270: Where: The parameter is the mole fr
Page 271 and 272: Reference C.H. Twu, "Internally Con
Page 273 and 274: Vcij 3 Transport Property Models 27
Page 275 and 276: You must provide parameters for the
Page 277 and 278: Linear extrapolation of � *,l ver
Page 279 and 280: If TRNSWT/4 is This equation is use
Page 285 and 286: Parameter Symbol Default MDS Lower
Page 289 and 290: References R.C. Reid, J.M. Prausnit
Page 291 and 292: The mixture surface tension is then
Page 295 and 296: Where: �solv = Dielectric constan
Page 297 and 298: 4 Nonconventional Solid Property Mo
Page 299: wij = Mass fraction of the jth cons
Page 303 and 304: Parameter Name/Element Symbol Defau
Page 305 and 306: The complete oxidation of carbon is
Page 307 and 308: Parameter Name/Element Symbol Defau
Page 309 and 310: The equation for �i dm is good fo
Page 311 and 312: 5 Property Model Option Codes The f
Page 313 and 314: Model Name Option Code 5 Property M
Page 315 and 316: Model Name Option Code 5 Property M
Page 317 and 318: Soave-Redlich-Kwong Option Codes Th
Page 319 and 320: Model Name Option Code HLRELNRT and
Page 321 and 322: Model Name Option Code GLRELNRT, GL
Page 323 and 324: Index A activity coefficient models
Page 325 and 326: ideal gas/DIPPR heat capacity model
Page 327 and 328: S Sato-Riedel/DIPPR thermal conduct
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Aspen Physical Property System - Physical Property Models

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