Thermodynamic Models
Thermodynamic methods
INDISS™ has its own thermodynamic module - called native or integrated thermodynamics - and may also work with external thermodynamic packages - called Property Packages - which are specific to Oil & Gas Industry: Upstream, Refining, Petrochemicals.
In all cases, streams handled in INDISS™ simulators are based on material, enthalpy and entropy balances. All stream properties are represented by means of a fully compositional approach with consistent phase behaviour in each simulation domain. The available thermodynamic models use either cubic equations of state or classical dissymmetric methods widely implemented in design software. In the same way as a design approach, High Fidelity phase behaviour calculations are obtained from models by Chao-Seader or Grayson-Streed for classical Refining and low pressure Petrochemical applications, to a flexible NRTL approach allowing satisfactory representations of complex mixtures of polar compounds.
HP Thermo (Upstream)
Property Package dedicated to High Pressure Petroleum applications with a high level true three-phase algorithms. This proprietary flash algorithm developed by TOTAL uses efficient oil-gas-aqueous stability tests. This algorithm works with most up-to-date numerical techniques insuring a reliable calculation under high pressure. Well and reservoir conditions are covered especially in the vicinity of the critical point. This algorithm uses the stability criteria by Baker (1981) and Michelsen (1982) with proprietary features. It operates and organises several levels of total convergence from the most common to the most sophisticated. At last, phase stability diffusion tests are used to provide the best deal between robustness and computation time saving. HPThermo includes a hydrate detection module. Hydrates checked may be of structure (I) or (II) and the model uses the van der Waals and Platteeuw theory (1959) to compute the activity of water in the solid phase. Functions of temperature of Langmuir constant is that suggested by Péneloux for the Peng-Robinson equations of state, while the correlation by Munk et al. (1988) is used with the Redlich-Kwong based equations of state. Furthermore, HPThermo implements more recent works developed on group contribution mixing rule approach by Péneloux et al. (1989), Abdoul et al. (1992). These characterization methods deal with reservoir, well and transport applications, Neau et al. (1993), Avaullée et al. (1997)(1997bis)(1997ter)(2001).
INDISS Thermo (Refining/Petrochemicals)
Property Package implements phase equilibria models for refining and petrochemical applications and addresses most widely used methods including:
- Ideal Raoult Low using reduced Antoine expression
- Equations of state like Peng-Robinson based equations of state (1976)(1978) and Mathias (1983) or Redlich-Kwong based equations of states (1949), Soave (1972)and Mathias (1983)
- Fugacity and activity coefficients models like Chao-Seader (1961) and Grayson-Streed (1963) methods, enhanced by Hildebrand-Flory combinatorial contribution; this property package includes a configurable NRTL model (1969)(1969bis), able to represent polar component / hydrocarbon interactions
- Enthalpy and entropy calculation using either equations of state or Hougen, Watson and Ragatz correlations (1959).
Bibliography
RSI SIMCON thermodynamicists actively contribute to develop modeling of thermodynamic methods.