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Aspen Physical Property System - Physical Property Models

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General Pure Component Heat<br />

of Vaporization<br />

The <strong>Aspen</strong> <strong>Physical</strong> <strong>Property</strong> <strong>System</strong> has several submodels for calculating<br />

pure component heat of vaporization. It uses parameter THRSWT/4 to<br />

determine which submodel is used. See Pure Component Temperature-<br />

Dependent Properties for details.<br />

If THRSWT/4<br />

is<br />

2 Thermodynamic <strong>Property</strong> <strong>Models</strong> 191<br />

Then this equation is used And this parameter is<br />

used<br />

0 Watson DHVLWT<br />

106 DIPPR DHVLDP<br />

301 PPDS DHVLDS<br />

401 IK-CAPE DHVLPO<br />

505 NIST TDE Watson equation DHVLTDEW<br />

DIPPR Heat of Vaporization Equation<br />

The DIPPR equation is used to calculate heat of vaporization when THRSWT/4<br />

is set to 106. (Other DIPPR equations may sometimes be used. See Pure<br />

Component Temperature-Dependent Properties for details.)<br />

The equation for the DIPPR heat of vaporization model is:<br />

Where:<br />

Tri = T / Tci<br />

Note: Reduced temperature Tr is always calculated using absolute<br />

temperature units.<br />

Linear extrapolation of �vapHi * versus T occurs outside of temperature bounds,<br />

using the slope at the temperature bound, except that �vapHi * is zero for<br />

.<br />

Parameter Symbol Default MDS Lower<br />

Name/Element<br />

Limit<br />

Upper<br />

Limit<br />

Units<br />

DHVLDP/1 C 1i — x — — MOLE-ENTHALPY<br />

DHVLDP/2, ..., 5 C 2i, ..., C 5i 0 x — — —<br />

DHVLDP/6 C 6i 0 x — — TEMPERATURE<br />

DHVLDP/7 C 7i 1000 x — — TEMPERATURE<br />

TC T ci — — 5.0 2000.0 TEMPERATURE<br />

Watson Heat of Vaporization Equation<br />

The Watson equation is used to calculate heat of vaporization when<br />

THRSWT/4 is set to 0. See Pure Component Temperature-Dependent<br />

Properties for details.

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