Software overview

The CPA equation of state is an equation of state (EoS) combining the Soave-Redlich-Kwong (SRK) EoS association term of Statistical Associating Fluid Theory (SAFT). It has been originally published by Kontogeorgis et al. (1996).

The CPA model is available, by CERE, in various formats and for different types of applications as mentioned below:

• SPECS: VLE and LLE calculations for various associating mixtures can be carried out.

• ThermoSystem: The CPA module can be used in any CAPE-OPEN compliant process simulators (e.g. Aspen HYSYS®, SimSci PRO/II) using. It also provides the option to use the CPA module in Aspen Plus® as a user model.

• Electrolyte CPA (eCPA) : MATLAB® tool for the calculation of activity coefficients and solubility plots for aqueous salt solutions including mixed salts

• Asphaltenes: MATLAB tool for the calculation of asphaltene phase envelope (PT plot including upper and lower onset boundaries) with gas injection effect.

• Gas Hydrate: MATLAB tool for the calculation of hydrate formation using CPA/qCPA with vdW-Platteeuw hydrate model.

• MAPS: Multicomponent adsorption calculations can be carried out using the MAPS software, combined with the MPTA theory by Alexander Shapiro and Erling Halfdan Stenby.

• Stand-alone program: The CPA model is available as a dynamic-link library (DLL), which can be used to access required thermodynamic properties and their derivatives so that it (CPA module) can be used in any in-house simulator. The stand-alone program to estimate pure compound CPA parameters is also available.

• CPA Dew Point Calculator: Dew point calculations, three-phase equilibrium temperatures, hydrate and frost formation calculations for natural gas containing water and/or production chemicals can be performed using the dew point calculator. The GERG based model calculator is also developed for the comparison of dew point.

Software Availability

SPECS and general CAPE-OPEN (ThermoSystem) description and instruction videos (for simulation of flow-sheet for natural gas processing) can be downloaded from the members section for the CERE member companies.

The Dew point calculator can be also downloaded from the member section for the CERE member companies.

All other CPA based modules/tools mentioned above are available for the members of CHIGP joint industry project.

Extended UNIQUAC (Universal QuasiChemical) is a thermodynamic (activity coefficient) model, specially designed for electrolyte solutions (both aqueous solutions and mixed solvents).

The vapor phase is described by the SRK equation of state. The model has been developed by Kaj Thomsen and Peter Rasmussen and it has been found widespread applicability. Both the model description and applications of the model can be found in an extensive material prepared by Kaj Thomsen which can be downloaded here

In CERE, Extended UNIQUAC can be used in many forms and for various applications as mentioned below:

• SPECS: For diverse calculations (activity coefficients, solid-liquid equilibria, thermal properties and binary, ternary and quaternary phase diagrams…) using the Extended UNIQUAC model. All calculations in SPECS are for aqueous electrolyte solutions. 
  
  A separate Electrolyte database is provided in SPECS.

• SCALE-CERE: For determining the risk of scale formation (precipitation of salts) as a function of temperature, pressure and composition of formation water/brine.

• CAPCO2: This module can be used in any process simulator, through CAPE-OPEN interface, to simulate the rate based column (absorber/desorber) for CO2 capture unit with aqueous ammonia or alkanolamines.

• Aspen Plus® User Model: The Extended UNIQUAC thermodynamic property package is developed in the form of user model to be used in Aspen Plus.

In addition to extended UNIQUAC, CERE has developed an extensive electrolyte database with over 150.000 experimental data collected from almost 3000 scientific papers.

Finally, CERE offers an on-line course on Electrolyte Solution Thermodynamics.

Software Availability

SPECS and SCALE-CERE can be downloaded from the members section for the CERE member companies.

Member companies can also order data free of charge from the electrolyte database.

Perturbed-Chain-Statistical-Associating-Fluid-Theory (PC-SAFT) is an equation of state developed by Gross and Sadowski (2001).

In CERE software, it is used in the simplified form developed a few years later by von Solms, Michelsen and Kontogeorgis (2003).The PC-SAFT model is available, by CERE, in various formats as mentioned below:

• SPECS: VLE and LLE calculations for both polymer and non-polymer systems can be carried out using PC-SAFT. A special PC-SAFT database should be selected under SPECS.

• ThermoSystem: The PC-SAFT/CPA module can be used in any CAPE-OPEN compliant process simulators (e.g. Aspen HYSYS®, SimSci PRO/II) using ThermoSystem. It also provides the option to use the CPA module in Aspen Plus® as a user model.

• Asphaltenes: MATLAB tool, based on the CPA/PC-SAFT module, for the calculation of asphaltene phase envelope (PT plot including upper and lower onset boundaries) with gas injection effect.

• Stand-alone program: The PC-SAFT model is available as a dynamic-link library (DLL), which can be used to calculate phase envelope, 2-phase flash and fugacity coefficients of multicomponent system. It can also be used to regress the pure compound PC-SAFT parameters.

Software Availability

SPECS and PC-SAFT/CAPE-OPEN in ThermoSystem, stand-alone DLL and executables as well as instruction videos can be downloaded from the members section for the CERE member companies.
CPA models and Asphaltene tool are available for the members of CHIGP joint industry project.

Various petroleum-related calculations are possible using the CERE software.

Using SPECS

It is possible to perform Slimtube simulations, performing minimum miscibility calculations, simulation of standard laboratory experiments with petroleum mixtures and investigation of equilibria in petroleum reservoirs. It is possible to perform oil characterization.

Using SNY

It is possible to evaluate formation damage under water flooding of a petroleum reservoir. The damage happens if the injection water contains particles that can penetrate and plug the porous rock.

Software availability

SPECS and SNY can be downloaded from the members section for the CERE member companies.

VLE (including at infinite dilution) and LLE calculations for polymer-solvent solutions can be carried out using SPECS.

The calculations can be performed with various activity coefficient models (Entropic-FV, UNIFAC-FV and UNIFAC) and with the PC-SAFT equation of state. Several polymers and solvents can be selected.

A special Polymer and PC-SAFT database should be selected under SPECS.

Software Availability

SPECS can be downloaded from the members section for the CERE member companies.

Transport Properties

Various transport properties can be calculated using CERE software.

Viscosity calculations can be made using SPECS.

Thermodiffusion coefficient calculations can be made using a special software (both in formats of excel and dll) and the results are compared to a large database of experimental data.

Software Availability
SPECS and Thermodiffusion can be downloaded from the members section for the CERE member companies.

Contact person: Associate professor Alexander Shapiro, ash@kt.dtu.dk