Information Technology Reference
In-Depth Information
CHAPTER TWO
PROPERTIES
Aspen Plus offers two possibilities for accessing properties: Property Analysis and
Property Estimation. Each is invoked from the drop-down, Run-type menu (Figure 2.1).
The Property Analysis function can display pure component values such as the criti-
cal compressibility factor, temperature-dependent properties such as the ideal gas heat
capacity, and mixture properties from a variety of data banks and mixture properties
from multicomponent functions such as equations of state. The Property Estimation
capability can be used to estimate virtually the same values as are stored in the Aspen
Plus database for user-defined components. References in this chapter to pure compo-
nent properties, equations of state, activity coefficient equations, and property equations
can all be found in the Aspen Plus Physical Property System documentation.
2.1 PURE COMPONENT DATA BANKS
All of the many data banks available in the Aspen Physical Property System can be
identified by clicking the Help button at the top of Figure 2.1. The primary database is
Pure22. To see the details of its content, searching Help for Pure22 will present various
alternatives, one being to display the Pure22 Databank. The list below, taken from
Aspen Plus's documentation, describes the property categories for which parameters
are stored.
• Universal constants, such as critical temperature and critical pressure
• Temperature and property of transition, such as boiling point and triple point
• Reference-state properties, such as enthalpy and Gibbs free energy of formation
• Coefficients
for
temperature-dependent
thermodynamic properties,
such as
liquid-vapor pressure
