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THERMODYNAMIC MODELING AND
THERMODYNAMIC COMPUTER SCIENCE


© 1998-2002 Gleb V. Belov                                                                                                                         

e-mail: gbelov@imail.ru

Glushko Thermocenter, IHED IVTAN Association of Russian Academy of Sciences

ВАРИАНТ НА РУССКОМ ЯЗЫКЕ             PAGE IN RUSSIAN


I would like to submit a kind of article concerning thermodynamic modeling. I did not plan to write the complete history of thermodynamic modeling, so, I did not touch the questions concerning the vapor-liquid equilibrium and the thermodynamics of the non-ideal solutions. This article reflects my personal vision of the state of the art.

DOWNLOADS

  1. Introduction
  2. Thermodynamic model
  3. Historical
  4. Thermodynamic and Thermochemical Properties of Individual Substances
  5. IVTANTHERMO for Windows
  6. Thermodynamic modeling at high pressure
  7. Thermodynamics in Internet
  8. Thermodynamic computer science
  9. Recent Publications

Introduction

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Methods of computational thermodynamics have been successfully used for the investigation of various processes and the development of new technologies for many years. Now there is no need to prove the practical value of calculation of equilibrium composition and properties of thermodynamic systems. A number of examples illustrating how thermodynamic calculations may be used as a basic tool in the development and optimization of materials and processes are presented in the excellent book

Hack, K. (ed). Thermodynamics at Work. Institute of Materials, London, 1996.
Below are listed some field of science and technology where thermodynamics works best

Thermodynamic model

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The basic concept of thermodynamics is thermodynamic equilibrium. Thermodynamic equilibrium is some final state of a thermodynamic system insulated from the external medium, i.e., there exists thermal, mechanical and chemical equilibrium in each point of the system and there are no flows. In practice, the requirement of isolation means that the processes leading to equilibrium occur faster than the changes on the system’s boundaries (external change of pressure, temperature and chemical composition, etc.) take place (local equilibrium hypothesis). For example, when thermodynamic examination of the combustion process is accomplished the adiabatic assumption is usual, i.e. heat losses are not taken into consideration. When the processes in chemical reactor are modeled, the common assumption is that the rates of chemical reactions are much higher than the velocity of flow, so, while the flow is in the reactor the chemical equilibrium is reached. Now, there are many evidences that the equilibrium model is valid for the high temperature processes (T > 1500 K) or when there is enough time to reach the equilibrium. Two examples of equilibrium systems are combustion products in the rocket engine chamber where equilibrium is reached in approximately 0.00001 s; some parts of the earth crust where millions of years required to reach equilibrium. However, sometimes another less restrictive hypothesis is used, which assumes partial equilibrium in the system. According to this hypothesis, due to slow rates of several reactions full chemical equilibrium cannot be reached, nonetheless it can be reached partially because another chemical reactions are fast enough.

The components of thermodynamic model are

So, the results of modeling depend on many parameters. The software for thermodynamic modeling now (see below) is usually supplied with a database on thermodynamic properties of substances. And the list of substances included in the system is determined mostly by the content of the corresponding database. The questions of quality of thermodynamic properties (uncertainties of the data) often are not taken into account. However, variation of the heat of formation of a substance in the system may often significantly change the results of calculations. In general, there is some contradiction between the quantity of substances in the system and the quality of their thermodynamic properties. One can say that often it is equally unreasonable to use for modeling too small list of substances with the reliable thermodynamic properties and an extensive list of substances with unreliable properties.

Often the question arise, can we believe the results of modeling? There is no definite answer to this question, it depends. The best way to get the answer is the comparison of results of calculations with the experimental data when possible. The researcher should have the answer to the following questions:

Sometimes the specific behavior of the system caused by the chemical kinetics of the processes may be taken into account by exclusion of some substances from the system if one knows from experiment that these substances cannot be formed. Another possibility is assignment of concentrations for one or several substances if there are some grounds to do that.

So, one may conclude that thermodynamic modeling is science and the art simultaneously. The researcher should "feel" the system that he/she investigates. 

Historical

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The famous study

Gibbs J.W. On the Equilibrium of Heterogeneous Substances. Trans. Connect. Acad., 1876, 3, pp. 108-248; 1878, 3, pp. 343-524.

provided the theoretical background for thermodynamic examination of complex chemically reacting system. The next remarkable book

Lewis G.N., Randall M. Thermodynamics and the Free Energy of Chemical Substances. NY. McGraw-Hill, 1923.

provided the bridge from the theory to practice. But only the appearance of computers allowed developing of appropriate instruments for thermodynamic modeling. One of the first algorithms of calculation of equilibrium composition was developed by S.R. Brinkley and H.J. Kandiner

Brinkley, S.R. Calculation of Equilibrium Composition of Systems of Many Constituents. J. Chem. Phys., 1947, v. 15, No 2, pp.107-110.

Kandiner H.J., Brinkley, S.R. Calculation of Complex Equilibrium Problem. Ind. Eng. Chem., 1950, v. 42, No 5, pp. 850-855.

Their algorithm used the concept of equilibrium constants. Then another algorithm based on minimization of the Gibbs energy appeared

White W.B., Johnson S.M., and Dantzig G.B. Chemical Equilibrium in Complex Mixtures. J. Chem. Phys. 1958, v. 28, No 5, pp.751-755.

The first "industrial" computer program supplied with the database on thermodynamic properties of substances has been developed by F.J. Zeleznik, S. Gordon and B.J. McBride

Zeleznik F.J., Gordon S. A General IBM 704 or 7090 Computer Program for Computation of Chemical Equilibrium Compositions, Rocket Performance, and Chapman-Jouget Detonations. NASA TN D-1454, 1962.

Gordon S., McBride B.J. Computer Program for Calculation of Complex Chemical Equilibrium Composition, Rocket Performance, Incident and Reflected Shocks and Chapman-Jouget detonations. NASA, 1971, SP-273.

See http://www.grc.nasa.gov/WWW/CEAWeb/ for more details.

The similar program has been developed in Russia, see

Alemasov V.E., Dregalin A.F., Tishin A.P. et al. Thermodynamic and Thermophysical Properties of Combustion Products. Moscow, 1971.

One should admit that the intensive development of the methods of thermodynamic modeling was caused by the development of the rocket engines. It would be impossible to create the modern rocket engines without the preliminary theoretical investigation of the combustion processes and the processes of the combustion products expansion where hundreds of simultaneous chemical reactions occur.

The next stage of the development of thermodynamic modeling is linked with metallurgy. Traditional metallurgical chemistry was based on investigation of the leading (or dominating) reactions. But this approach is very unreliable, as variation of parameters (temperature, pressure, source composition) often changes the list of the leading reactions. So, computational thermodynamics appeared helpful for the examination of metallurgical processes, see

Eriksson G. Thermodynamic Studies of High Temperature Equilibria. Acta Chem. Scand., 1971, v.25, No 7, pp.2651-2658.

Eriksson G., Hack K. ChemSage - a Computer Program for the Calculation of Complex Chemical Equilibria. Metallurgical Trans. B, 1990, v. 21B, pp.1013-1023.

Siniarev, G.B., Vatolin, N.A., and Trusov B.G. Primenenie EVM dlia termodinamicheskih raschetov metallurgicheskih processov (ThermodynamicModeling of Metallurgical Processes with Computer). Nauka, Moscow, 1982.

The last book (Siniarev et al.) contains FORTRAN source codes of the powerful computer program for the calculation of complex chemical equilibrium developed by Prof. B.G. Trusov (Bauman Moscow State Technical University). Now, there exist hundreds of algorithms and computer programs intended for the calculation of equilibrium composition of thermodynamic systems. A detailed review of many of them is presented in

Van Zeggeren F., Storey S.H. The Computation of Chemical Equilibria. Oxford: Cambridge Univ. 1970.

Holub R., Vonka P. The Chemical Equilibria of Gaseous Systems. Dordrecht: Reidel Pub. Comp. 1976.

Smith W.R., Missen R.W. Chemical Reaction Equilibrium Analysis: Theory and Algorithms. NY, John Wiley, 1982.

The last book (Smith) also contains the FORTRAN and BASIC source codes for the calculation of complex chemical equilibrium.

There are several reasons for the existence of this lot of algorithms. The first one is the great variety of thermodynamic systems with their specific features (e.g. combustion processes and the processes in the earth crust) and as a result, there are many thermodynamic models. Parameters of most models are known only for small group of substances. Determination of parameters of models requires in general reliable experimental data and sound theoretical basis, so it is the problem itself. The situation is complicated by the fact that the relations among equilibrium composition and the model parameters are nonlinear. Phase composition of the equilibrium system is usually unknown a priori and it must be found in calculation process. So, the target function is not continuous, it can have disruptions at the phase transitions points. This circumstance embarrasses the solution of the problem. Besides, sometimes approximately the same value of the target function exists for different phase and chemical compositions of thermodynamic system examined and it is very easy to find the false solution. One should also take into account the  "limited" mathematics of the computer, which can accomplish calculations only with limited number of significant digits. Therefore, even if mathematics guarantees the solution for some algorithm the computer version of the algorithm will fail in some cases.

Calculation of the equilibrium composition of the system may be accomplished through the solution of a set of the nonlinear equations. The questions of existence and uniqueness of the solution are reviewed in many sources, see Smith W.R., and Missen R.W. for example. It is shown that if the gas phase behavior is described by the ideal gas equation of state and the condensed mixtures are ideal the target function is convex and there usually exists a unique solution.

Thermodynamic and Thermochemical Properties of Individual Substances

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The basis, the intrinsic part of any serious computer system, intended for accomplishing thermodynamic modeling, is a database on thermodynamic properties of individual substances. The main sources of this information are the reference books

Gurvich, L.V., Veitz, I.V., et al. Thermodynamic Properties of Individual Substances. Fourth edition in 5 volumes, Hemisphere Pub Co. NY, L., Vol1 in 2 parts, 1989, etc.

Chase M.W., Curnutt J.L., Hu A.T., Prophet H., et al. JANAF Thermochemical Tables. Third Edition, 1985.

Barin I., Knacke O., Kubaschewski O. Thermochemical Properties of Inorganic Substances. Springer-Verlag, Berlin, 1977.

The problems concerning the quality of thermodynamic data are discussed in

Iorish V.S., Belov G.V. On Quality of Adopted Values in Thermodynamic Databases. Netsu Sokutei, 1997, 24 (4), pp. 199-205.

G. V. Belov, B. G. Trusov,  Influence of Thermodynamic and Thermochemical Data Errors on Calculated Equilibrium Composition, Ber. Bunsenges. Phys. Chem. v. 102, No. 12, pp.1874 -1879, 1998

The last references contains information about other data sources.

IVTANTHERMO for Windows

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In Thermocenter of the Russian Academy of Science during many years is being carried out a theoretical study of thermodynamic properties of individual substances and accumulation of this information in form of the reference book and a database. This information is intended for scientists and engineers who work in various branches of science and engineering and it must be delivered them in an easy-to-handle form.

The most characteristic feature of IVTANTHERMO is that the stored information is not borrowed from any other data bases or reference books. This information is obtained by means of critical analysis and treatment of the original data available in literature. Primary information analysis and all necessary calculations have been performed with the use of original methods, algorithms and software, developed for the ‘Thermodynamic Properties of Individual Substances’ handbook and updated by its authors for the IVTANTHERMO database. Now the database contains information about approximately 2500 substances formed by 96 chemical elements.

To enable the researchers and engineers to investigate thermodynamic systems of various kinds the software IVTANTHERMO has been developed. Recently a new version of the software appeared, which consists of six programs and the database on thermodynamic properties of individual substances. The software has an intelligible interface, which does not require from user special computer knowledge. All six programs with the database represent one complex - IVTANTHERMO for Windows. The programs are

Prof. Trusov B.G. (Bauman Moscow State Technical University, e-mail: trusov@iu7-head.bmstu.ru) participated in the development of the software IVTANTHERMO for Windows.

Download the trial version of the software (includes THERBASE, EQUICALC and small database), about 0.9 MB.

Download the manual, about 0.4 MB.

Download the list of substances, about 20 KB.

Thermodynamic modeling at high pressure

The ideal gas equation of state is most frequently used in thermodynamic calculations. And this assumption is valid for many cases. However, if the density of the gas phase is high enough (e.g., temperature is low or pressure is high) a real gas equation of state should be used. Click here for more details. 

 

Thermodynamics in Internet

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The appearance and wide spreading of the world wide nets mark the new stage in development of thermodynamic modeling. Now one can use the remote computers for the calculations. However the standalone computers still keep their positions and it is more comfortable to have own software on the table.

Below are listed the references to some interesting sites where thermodynamic and thermochemical information can be found. The list inevitably is not full and contains only those references that I have managed to find. The brief descriptions are borrowed from the original sources.


http://www.kintech.ru/

Chemical WorkBench  the simulation software tool intended for modeling, optimization and design of a wide range of industrially, environmentally or educationally important chemistry loaded processes, reactors and technologies. Chemical WorkBench  is a chemistry-centered, desktop simulation environment for detailed, user-friendly, complete-cycle physico-chemical modeling of  the chemically-related processes, reactors and technologies. Chemical WorkBench is a well-furnished suite of software tools enables researchers and engineers to model the "virtual prototypes" of chemically-active systems, and to simulate their operation behavior before detailed engineering and physical prototyping. Its most attractive feature is possibility to model real complicated process by means of chains of reactors. Among the reactors available there are not only equilibrium thermodynamic reactor, but also nonequilibrium reactors that take into account chemical kinetics, these are plug-flow reactor, calorimetric bomb, well-stirred reactor, etc. The researcher can combine these reactors on the virtual workbench, define links among them, set input species and parameters, accomplish calculations and visualize the results of modeling.


http://www.ReactionDesign.com

 

Reaction Design of San Diego, California, USA, was founded in 1995 to provide software simulation and modeling tools to help process engineers create more efficient and environmentally friendly manufacturing processes.  In 1997, Sandia National Laboratories selected Reaction Design as the exclusive worldwide licensee for its CHEMKIN Collection and other software, which it had developed to aid in the design of processes that 
utilize chemical reactions. 

Reaction Design is focusing its development, consulting and marketing efforts on four chemistry-intensive process areas: 

 

The flagship product of the company is CHEMKIN software

The CHEMKIN Collection facilitates the formation, solution, and interpretation of problems involving gas-phase and heterogeneous (gas-surface) chemical kinetics. The Collection's programs and subroutine libraries are flexible and powerful tools for incorporating complex chemical kinetics into simulations of reacting flow. CHEMKIN tools provide solutions for Combustion, catalysis, chemical vapor deposition, and plasma etching. 

The CHEMKIN Utilities consist of the Following Subroutine Libraries and Pre-processors: 

 


http://www.kintecus.com/

 

Kintecus - chemical modeling software for simulation of combustion, nuclear, biological, enzyme, atmospheric and many other processes. One prime feature is the ability to quickly run Chemkin/SENKIN II/III models without the use of supercomputing power or FORTRAN compiling/linking. Multiple Chemkin/freestyle thermodynamic databases can be used. Isothermal/Non-isothermal, adiabatic constant volume, constant pressure (variable volume) can easily be modeled with a flick of a switch. Programmed volume (replicating engine piston motion), programmed temperature, programmed species concentration can all easily be included in user's model WITHOUT C/FORTRAN programming. Heterogeneous chemistry is also easily modeled.

 

Kintecus is a compiler to model the reactions of chemical, biological, nuclear and atmospheric processes using three input spreadsheet files: a reaction spreadsheet, a species description spreadsheet and a parameter description spreadsheet. For thermodynamics, an optional thermodynamics description spreadsheet can be supplied.

 


 

http://webbook.nist.gov

The NIST JANAF Thermochemical Tables provide a compilation of critically evaluated thermodynamic properties of approximately 1800 substances over a wide range of temperatures. Recommended temperature-dependent values are provided for inorganic substances and for organic substances containing only one or two carbon atoms. These tables cover the thermodynamic properties with single-phase and multi- phase tables for the crystal, liquid, and ideal gas. The properties tabulated are:  heat capacity, entropy, Gibbs energy function, enthalpy, enthalpy of formation, Gibbs energy of formation, logarithm of the equilibrium constant for formation of each compound from the elements in their standard reference states. This database is consistent with the Third Edition of the JANAF Thermochemical Tables, published as Supplement No. 1 to Vol. 14 of the Journal of Physical and Chemical Reference Data.


http://www.trc.nist.gov

    The Thermodynamics Research Center (TRC) specializes in the collection, evaluation and correlation of thermophysical, thermochemical and transport property data for organic compounds.  As a part of the Physical and Chemical Properties Division at National Institute of Standards and Technology, TRC is located in Boulder, Colorado. 

    A goal of TRC is to establish a large, general-purpose archive of experimental data covering thermodynamic, thermochemical, and transport properties for pure compounds and mixtures of well-defined composition, and to maintain coverage as new data appear.  It is critically important that the data evaluation includes the estimated uncertainties for practically all the numerical data stored.  This feature allows, in principle, determination of the quality of recommended data based upon the original experimental data collected at TRC.

    There are four major types of information stored in this archive - an in-house database.

·        Compound Identification. Registry numbers identify pure compounds and components of mixtures throughout the archive. Registry numbers link to an empirical formula, a coded representation of the structural formula, and to one or more names. The database contains 113,000 registry numbers and 218,000 names. Reacting systems of one or more compounds also receive registry numbers. Among the stored compounds, approximately 15,800 pure compounds, 9,000 binary and ternary mixtures, and some 2,500 reaction systems have data records. Chemical reactions have a classification code and registry numbers of four species in the reaction.

·        Sample Descriptions. The database describes over 17,900 distinct samples used in property measurements. The description includes: source of sample, method of purification, and final purity as reported by the authors of the document. Formal abbreviations exist, and by sample numbers identify different samples of the same compound used for measurements in the same document.

·        Literature References. The database contains citations of original documents and associated information (such as titles, document types, classification of information, and comments) and links to data values. Names of authors appear in a dedicated table linked to the citations. Thus, it is possible to retrieve literature references by year of publication, author, compound identity, property, or combinations of them. The database contains 82,000 citations, of which, over 22,000 citations contribute numerical values to the database.


http://www.lerc.nasa.gov/WWW/CEAWeb/

 

The NASA Computer program CEA (Chemical Equilibrium with Applications) calculates chemical equilibrium compositions and properties of complex mixtures. Applications include assigned thermodynamic states, theoretical rocket performance, Chapman-Jouguet detonations, and shock-tube parameters for incident and reflected shocks. CEA represents the latest in a number of computer programs that have been developed at the NASA Lewis (now Glenn) Research Center during the last 45 years. These programs have changed over the years to include additional techniques. Associated with the program are independent databases with transport and thermodynamic properties of individual species. Over 1900 species are contained in the thermodynamic database. The program is written in ANSI standard FORTRAN by Bonnie J. McBride and Sanford Gordon. It is in wide use by the aerodynamics and thermodynamics community.

 


 

http://www.npl.co.uk/npl/cmmt/mtdata/mtdata.htm

MTDATA is a software/data package for the calculation of phase equilibrium in multicomponent multiphase systems using, as a basis, critically assessed thermodynamic data. It has numerous applications in the fields of metallurgy, chemistry, materials science, and geochemistry depending only on the data available. Problems of mixed character can be handled, for example equilibrium in involving the interaction between liquid and solid alloys and matte, slag and gas phases. The thermodynamic models necessary to describe the properties of a wide range of phase types are incorporated in the software and database structures.


http://www.thermocalc.se

Thermo-Calc is a software package for equilibrium and phase diagram calculations. It can be applied to any thermodynamic system in the fields of chemistry, metallurgy, material science, alloy development, geochemistry, semiconductors etc. depending on the kind of database it is connected to. It can also be used as a subroutine package in application programs, for example in phase transformation or process simulations. Thermo-Calc consists of modules for the various tasks the user may be interested to perform. There are modules for the selection of database and data, for listing thermodynamic data or interactive manipulation and entering of such data. The most important module for equilibrium calculation together with its post processor makes it possible to calculate and plot diagrams of many different kinds on all kinds of devices. A useful facility in Thermo-Calc is the module for assessment of experimental data in terms of thermodynamic models. There is also a module for tabulation of data for substances or chemical reactions. The user may also develop and add own modules by using a documented software interface. With Thermo-Calc one may simulate processes where the time-dependence can be ignored, for example by stepwise calculation of a sequence of equilibria with transfer of heat and matter between the equilibria.


http://www.kagaku.com/malt

MALT2 is a comprehensive Materials-oriented Little Thermodynamic Database for Personal Computers. The task group of the thermodynamic database was organized in the Japan Society of Calorimetry and Thermal Analysis. MALT2stores thermodynamic data such as the standard enthalpy change for formation, DfH(298.15 K), the standard Gibbs energy change for formation, DfG(298.15K), the standard entropy, S(298.15 K), the heat capacity, Cp, and the transition temperature and the enthalpy change for transition, if any, for 4931 species; this covers those compounds important to ceramic materials, semiconductors, inorganic /organic gasses for plasma processes in semiconductors, transition metal oxides, nuclear fuels, nuclear reactor materials etc. From such stored data, the thermodynamic tables and the equilibrium constants at any temperatures can be calculated. In addition, molecular mass, coefficient of heat capacity equation, and references for data can be also available.


http://www.outokumpu.fi/hsc/

HSC Chemistry is made in Outokumpu Research Oy. However, many of the important calculation options are based on the code and ideas from other sources. The aim of this software is to simulate the chemical reaction equilibrium and processes in the personal computer in order to develop new processes and improve the old ones. HSC Database is a compiled database on thermodynamic properties of individual substances. The number of species in the database is more than 10000. These data are not critically evaluated, but give a fast access to data and references, which can be found from the literature. The database also has fields for Structural Formula, Chemical Name, Common Name, CAS number, melting point, boiling point, color and solubility to H2O. The data in these fields are not yet complete but even now they can help, for example, to identify organic substances.


http://www.uic.edu/~mansoori/Thermodynamic.Data.and.Property_html

Thermodynamic Data and Property Calculation Sites on the Web.


http://blue.caltech.edu/tcc/index.html

ThermoChemical Calculator (TCC)  is a WWW tool to carry out thermochemical calculations for ideal gas mixtures. It makes use of Chemkin, and includes a database of properties for many species of interest for combustion, atmospheric chemistry, or chemical vapor deposition problems.

Some of the things you can do are


http://www.mathtrek.com/

EQS4WIN is a powerful and easy-to-use software package that solves a wide range of problems related to the calculation of the reaction and phase equilibrium composition of complex chemical systems. EQS4WIN incorporates up-to-date technology in numerical analysis, programming, and thermodynamics. It was written under the supervision of Dr. W. R. Smith, senior author of a classic text in the field (see Ref. above). EQS4WIN solves equilibrium problems by minimizing the overall Gibbs free energy of systems involving up to 4 multi-species ideal-solution phases (a gas phase and up to 3 condensed liquid or solid solutions) and any number of pure (condensed) phases. Calculations can be performed for several different types of thermodynamic conditions, either at a single state point, or for up to two simultaneously varying parameters. All versions of EQS4WIN incorporate a thermochemical database based on the species listed in the JANAF Tables.


http://www.crct.polymtl.ca/fact/fact.htm

 

F*A*C*T - Facility for the Analysis of Chemical Thermodynamics. The F*A*C*T is a fully integrated thermochemical database which couples software for thermodynamic modeling with critically assessed thermodynamic data. Originally developed as a research tool for chemical metallurgists, F*A*C*T is now employed in many diverse fields of chemical thermodynamics by chemical engineers, corrosion engineers, organic chemists, geochemists, ceramists, electrochemists, and so on. Information about F*A*C*T databases as well as many references to similar WWW sites in inorganic chemical thermodynamics may be found at this site.


http://gttserv.lth.rwth-aachen.de/~sp/tt

 

ChemSage is a direct descendant of the widely used SOLGASMIX Gibbs energy minimiser program developed by Dr. Gunnar Eriksson nearly 30 years ago. ChemSage was first released in 1987 and represented a significant development of the original program. In combination, the two programs have the greatest frequency of quotation in the technical literature. The ChemSage 'engine' also forms the basis for a number of other similar software programs. ChemSage modules permit calculation of thermodynamic properties of single solution and stoichiometric condensed phases with respect to a chosen reference state, calculation of the chemical equilibrium state of a system that is defined with regard to temperature, pressure or volume, and total amounts and/or equilibrium activities of any phase constituent in the system, calculation of temperatures when precipitates are formed from the liquid, of adiabatic temperatures, simulation of a multi-stage reactor by defining energy and material flows between stages , optimisation of thermochemical data based on experimental information, results to be saved as plot-files, displayed and printed graphically, or exported to other applications. Every copy of ChemSage comes with a basic thermochemical database of approx. 1300 substances.


http://www.olisystems.com

 

Over the past 25 years, OLI has refined software which accurately models multiphase, multicomponent aqueous solutions for virtually any mixture of chemicals. The basis for OLI’s Software is the "OLI Engine." The OLI Engine is made up of the Solvers and the software packages StreamAnalyzer, OLI Express, and the WaterAnalyzer.

 

The OLI Thermodynamic Framework provides accurate prediction of multicomponent aqueous systems including aqueous liquid, vapor, organic liquid, and multiple solid phases over the general range of 0 to 30 molal, -50 to 300 °C, and 0 to 1500 Bar. Computed thermodynamic properties such as pH, ionic strength, enthalpy, density, osmotic pressure are supplied automatically.

 

The OLI Databank contains thermodynamic, transport, and physical properties for 79 inorganic elements of the periodic table, and their associated aqueous species, as well as over 3000 organics. Thus, most mixtures of chemicals in water can be modeled, provided the solvent of the solution is water.

 

The Environmental Simulation Program (ESP) is a steady-state process simulator with a proven record in enhancing the productivity of engineers and scientists.  ESP provides the engineer or scientist accurate answers to questions involving complex aqueous systems.  The dynamic response of a process can be studied using the dynamic simulation program, DynaChem, to examine control strategy, potential upsets, scheduled waste streams, controller tuning, and startup/shutdown studies.

 


Thermodynamic computer science

The wide spread of computers and introduction of methods of mathematical modeling into the practice of scientific and engineering researches caused an intensive development of many branches of science and technology. Thermodynamic modeling may be treated as a kind of mathematical modeling, and for many years it is used successfully for the investigation of high temperature processes in complex systems. In order to stress the role of computer in thermodynamic research such terms as “computational thermodynamics”, “applied chemical thermodynamics” and “thermochemical informatics” were proposed by various authors. We think “thermodynamic computer science” is more appropriate term in this case taking into account that computer is used in thermodynamics not only for calculation purposes but also for gathering, storage, search, treatment, transformation, dissemination and utilization of the data about physico-chemical properties of substances. In other words there exists the branch of thermodynamics that uses methods and instruments of computer science to solve its specific problems with the aid of computer.

The following items may be related to the jurisdiction of thermodynamic computer science:

  1. assessment of thermodynamic and thermochemical properties of individual substances;  
  2. development of data storage and data exchange formats;
  3. development of databases on physico-chemical properties of substances;
  4. development of data access methods in databases, which provide the possibility of data import and export, and presentation of thermodynamic information in table and graphical forms;
  5. creation of new thermodynamic models and perfection of existing ones;
  6. development and perfection of methods, algorithms and software for thermodynamic modeling of complex chemical equilibria;
  7. development of methods of analysis of the results of thermodynamic calculations;
  8. development of methods of evaluation of model parameters’ uncertainties upon the results of calculation of equilibrium composition;
  9. development of user’s interface for thermodynamically oriented software;
  10. development of thermodynamic and thermochemical class libraries to facilitate the execution of such routine procedures as data storage, calculation of thermodynamic functions of a substance or thermodynamic properties of chemical reaction for assigned pressure and temperature, etc.

 

Feedback: gbelov@imail.ru

Last modified January, 2002
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