RECENT PUBLICATIONS

V.S. Iorish, G.V. Belov. On Quality of Adopted Values in Thermodynamic Databases. Netsu Sokutei (Calorimetry and Thermal Analysis), v. 24, No. 4, 1997, pp.199-205.

**Abstract**

Thermodynamic data bases are widely used in scientific research, engineering calculations, physicochemical experiments planning as well as for teaching and other purposes. Progress of recent decades in petrochemistry and metallurgy, creation of rocket engines and modern structural materials, development of traditional and nuclear power engineering and many others could not have been achieved without preliminary thermodynamic analysis of the relevant processes. Successful solution of many global problems facing humankind today depends to some extent on the reliability of theoretical models of complex physicochemical systems. One of the most important parts of such models is set of thermodynamic properties of the system being studied. The development of new methods of supplying humankind with energy, the choice of the optimum ways for utilization of industrial wastes, solution of the safety problems of nuclear power engineering, as well as solution of many other problems will be impossible without preliminary analysis based on thermodynamic modeling.

Basic part of any complex petrochemical system's model incorporates an idea about individual substances. The characteristics of the whole system are largely determined by the properties of substances, which form the system. That is why so necessary are further experimental and theoretical study of thermodynamic properties of individual substances and accumulation of this information. 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 intelligible form. One may regard the thermodynamic properties of substances (enthalpy of formation, heat capacity, entropy etc.) as fundamental physicochemical properties, which are used for analysis of processes with participation of these substances in a wide range of pressure and temperature. However the array of thermodynamic properties as distinct from fundamental physical constants is practically unlimited, it is determined first of all by multitude of species in various phase states. Because of perpetual growth of the experimental and theoretical information about substances it is necessary to systematize it in the form of reference books, as well as in the electronic form (data bases and data banks).

The evaluation of quality of the information published in reference books and stored in data bases is a very complicated task. Still more difficult and practically insoluble task is the evaluation of results of the use of unreliable information for thermodynamic analysis of various processes. Main reason of complexity of the first task is absence of the complete information about the adopted values, i.e. absence of all primary data and details of their processing. It should be mentioned here that well known problem of thermodynamic consistency can't be investigated within limited set of data, it's necessary to take into consideration information from other data bases or original data sources. Another reason of the problem complexity is difficulties of algorithmization of the data quality expert analysis procedure, which is usually fulfilled by qualified specialists. At present it is not easy to find financial support for such investigations, and the number of qualified specialists in this area is very small.

In present report we are trying to evaluate data quality of one of known data bases by means of computer processing, to carry out the analysis of reasons that caused gross errors and to discuss possible ways of their preventing.

V.S. Iorish, G.V. Belov, V.S.
Yungman

IVTANTHERMO FOR WINDOWS AND
ITS USE FOR THE APPLIED THERMODYNAMIC ANALYSIS (Preprint of IVTAN), 1998.

**Abstract**

The present study consists of two parts. The first part contains a detailed description of the concept and basic abilities of IVTANTHERMO for Windows. The software includes a database on thermodynamic properties of approximately 2600 substance formed by 96 chemical elements, and six independent programs that allow to work with database, to calculate equilibrium composition and thermodynamic parameters of complex chemically reacting systems, to investigate possible correlation among thermodynamic properties of substances stored in the database, to compute polynomial coefficients that fit the temperature dependent thermodynamic properties, to accomplish heat balance calculations.

In the second part the algorithm of calculation of equilibrium composition of thermodynamic systems implemented in IVTANTHERMO is described. Some results of calculations that demonstrate the abilities of the software are presented.

Belov G.V. Thermodynamic analysis of combustion products at high pressure and temperature. Propellants, Explosives, Pyrotechnics. v.23, No 2, pp. 86-89, 1998.

**Abstract**

**C**hemical energy of the fuel, which during burning process is
converted into the heat energy, is wide spread an energy source for thermal
energy units. The transformation of the heat energy into mechanical is
performed with the use of working body, which used to be formed by combustion
products. In order to enhance energy and performance characteristics of the
latter special additions to the fuel are used. These additions may contain
various chemical elements different from traditional C, H, O and N. Evaluation
of thermodynamic and physical properties of combustion products in order to
detect optimal parameters of working processes in energy units is often
necessary. Experimental ways of obtaining of this information are expensive and
time consuming, because the gas temperature is usually very high.

In the high temperature range is often successfully used an equilibrium model, which allows to use methods of thermodynamics for analysis of the processes. In this case the task is reduced to calculation of phase and chemical composition, which in its turn is used for computation of equilibrium parameters of the system.

Common way of enhancing performance characteristics of thermal energy units is pressure growth. If temperature of the system is more than 1000 K and pressure is below 20 MPa, the behavior of the gas phase is adequately described by the ideal gas equation of state. However if pressure in the system is very high, the deviation from ideal gas behavior becomes significant and a real gas equation of state should be used in calculations.

Objective of this work was development of an algorithm intended to perform computer modeling of a complex chemically reacting system. The algorithm is derived from an older version of well known in Russia ASTRA algorithm. The latter is based on fundamental thermodynamic principle, formulated by Gibbs, from which it follows that entropy of insulated system is maximum in equilibrium state. The developed algorithm was used for elaboration of a computer program REAL, supplied with an extensive data base on thermodynamic properties of individual substances.

A.K. Zaytsev, L.I. Leontiev, Y.S.
Yusfin, G.V. Belov, V.S. Iorish On principles of thermodynamic modeling of
dioxins formation and behavior in thermal processes. Organohalogen Compounds,
v. 36, 1998, pp. 197-200

**Abstract**

The investigation of formation and behavior in thermal processes of polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF), both of which are often named “dioxins”, is important in two aspects. On the one hand, various thermal technologies including the incineration of the domestic and industrial wastes are recognized as a significant source of the dioxins emission into environment. On the other hand, these technologies are recognized as one of the main methods of the annihilation of these extremely toxic compounds. So, the theoretical analysis and prediction of PCDD/F formation in the wide range of temperature values, redox conditions and the source composition is of primary importance. The best way of obtaining of this information is the thermodynamic modeling (TM) based on calculation of equilibrium composition. The equilibrium concentrations of PCDD/F should be regarded as maximum available values, what is the goal of an ecological examination. It should be noted that TM allows take into account some kinetic restrictions by excluding some substances from the list of possible products or by assigning the fixed values for the concentrations of some products.

To apply the TM to the problem discussed one should create a database on thermodynamic properties of individual substances and develop the algorithms and related software. The database and software should make it possible to accomplish all necessary calculations, informativity and the simplicity of the analysis of the results of calculations, because the hundreds of substances may be regarded as possible products. The solution of these tasks led to the development of the new version of IVTANTHERMO for Windows, which is supplied with the extensive database on thermodynamic properties of substances.

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

**Abstract**

Thermodynamic modeling is widely used now for the investigation of metallurgical and other high temperature processes. So the problem of reliability of the results of thermodynamic modeling is very important. Reliability of the results of thermodynamic modeling is determined mostly by the following factors:

- adequacy of the process model used, i.e., by the correctness of the adopted assumptions and, first of all by the correctness of the assumption concerning the existence of thermodynamic equilibrium in the system examined;
- quality of the information on thermodynamic and thermochemical properties of individual substances, i.e., by the errors of the data;
- completeness of the list of substances taken into account.

In present study an attempt is made to estimate the
influence of the errors in thermodynamic and thermochemical data upon the
results of thermodynamic calculations. It was found that this factor often
being neglected may be very important. Special attention to data errors should
be paid when a complicated model with many parameters is used for analysis of
the process.

In practice investigators often explain discrepancy between the
experimental data and the results of calculations by absence of chemical
equilibrium in the system or by wrong parameters of the model used, while the
true reason may be the errors of thermodynamic data. This problem has
been examined in the past. But the approach used in these works is based on an
assumption that the thermodynamic data errors does not influence upon the phase
composition of the system investigated. This assumption is not valid in general
case.

While investigating the influence of thermodynamic data errors upon the results of modeling one needs an answer to the following questions:

- how will change the results of calculations with variation of standard chemical potential of a substance or group of substances (sensitivity analysis); the sign and magnitude of the change are interesting first of all;
- which will be the scatter of calculated values because of the possible changes of the adopted value of standard chemical potential of a substance (or group of substances) within its uncertainty interval.

The answers to these questions allow on the one hand to detect the upper and the lower limits of the calculated results. On the other hand this information may help to define more precisely the uncertainties of properties of individual substances by comparing the experimental data and the results of modeling.

G.V. Belov, V.S. Iorish, V.S.
Yungman. IVTANTHERMO for Windows – Database on Thermodynamic Properties and
Related Software. CALPHAD, Vol. 23, No. 2, 1999, pp. 173-180.

**Abstract**

Importance of thermodynamic modeling cannot be overestimated. 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 *Thermodynamics at Work*. Of course,
thermodynamic modeling cannot absolutely substitute the experiments. However,
it may help to estimate the area of parameters where the experiment should be
accomplished. As the computer becomes more custom instrument for a researcher,
applicability field of methods of computational thermodynamics is perpetually
growing. And the requirements to related software are growing too. Now any
serious computer program intended for thermodynamic modeling of processes
should contain at least three parts: the database on thermodynamic properties
of substances, modeling software itself and special service software for
database handling. A software interface should be clear and intelligible. The
user should not spend too much time for reading manuals before he can
accomplish simple calculations. The database on thermodynamic properties should
be reasonably extensive and reliable, as incompleteness of information or wrong
data may easily result in errors of modeling and therefore in lost of time and
efforts.

All the requirements mentioned were taken into consideration at the development of IVTANTHERMO for Windows.

The whole software package IVTANTHERMO contains the database and six programs:

- THERBASE - tool for database handling;
- EQUICALC - tool for modeling;
- APPROX - a supplementary tool for the new thermodynamic data input;
- DATANAL - a program for statistical analysis of information in the database;
- HB - a program which calculates heat and material balance in thermodynamic system;
- REPORTER - supplementary tool for printing results.

The database and software allow to carry out theoretical study of the

- possibility and optimal parameters of various new high temperature processes;
- optimization of conditions for the synthesis of chemical compounds including refractory materials and materials for microelectronics;
- stability of refractory materials at high temperature and in aggressive atmosphere;
- processes that occur in power-generating facilities including nuclear ones;
- conditions for the optimization of chemical engineering and metallurgical processes;
- optimization of utilization of raw materials and the processing of industrial waste products;
- processes resulting in emission of noxious combustion products and gas phase industrial waste into the atmosphere;
- methods intended for prevention of environmental pollution etc.

An extensive database on thermodynamic properties of individual substances and modeling abilities make IVTANTHERMO a useful tool for scientists, chemical engineers, who investigate high temperature processes with chemical transformations, and for the senior students of chemical engineering departments. As the software has relatively simple interface, accomplishing of thermodynamic calculations is possible without the thorough study of documentation. The basic modules of IVTANTHERMO are supplied with a chart analyzer. So the user can easily convert most of the data or the results into curves, which can be modified, printed or exported to other programs.

G. V. Belov, V. S.
Iorish, and V. S. Yungman. Simulation of
Equilibrium States of Thermodynamic Systems

Using IVTANTERMO for Windows. High Temperature. Vol. 38, No. 2, 2000, pp.
191 - 196.

**Abstract**

An algorithm is suggested for the
calculation of the equilibrium composition of multicomponent heterogeneous
thermodynamic systems, as well as a method and algorithm for the calculation of
the pressure of saturated vapors over the condensed phase. These algorithms
were used in developing the IVTANTERMO software package for Windows.

Belov G.V.** **Computation of Equilibrium
Composition and Properties of Thermodynamic Systems at High Pressure.//Mathematical Modeling. – 2001. - V.13, No. 8.
- P.9-12.

**Abstract**

** **

A
method, algorithm and a software for calculation of equilibrium composition and
properties of thermodynamic systems at high pressure are presented. Some
results of thermodynamic modeling that demonstrate the abilities of the
algorithm and software are shown.