Studies in the computation of thermodynamics

Abstract

Thermodynamic properties of substances like entropy and enthalpy are important in the study and design of the processes involving liquefaction, solidification, refrigeration, heat transfer, gas separation, and in chemical reactions, to mention a few. Thermodynamic properties—experimental or calculated—also help in elucidating the intermolecular properties and in testing the theories of gases and liquids. In the present investigation, thermodynamic properties of three chloromethanes namely, carbon tetrachloride, chloroform and methylene chloride, and three industrially important substances namely chlorine, carbon disulphide, and phosgene, and of the chemically reactive system 2NO2⇋2NO+O22NO_2 \leftrightharpoons 2NO + O_22NO2​⇋2NO+O2​ have been calculated. The thesis is divided into four parts. They are: Part 1: This part consists of computation of thermodynamic properties of chloromethanes. The properties have been evaluated utilizing the available data and following the equation of state method to evaluate the properties. This part comprises four sections. Section 1 pertains to the general method followed and the subsequent sections detail the literature and the computation of the properties of each substance. Part 2: This deals with the correlation of evaluated thermodynamic properties of chloromethanes based on the law of corresponding states coupled with the reference substance concept. The properties of methane and methyl chloride have been derived from literature and the properties of methylene chloride, chloroform and carbon tetrachloride used are those computed and presented in Part 1. Part 3: In this part, the thermodynamic properties of the chemically reactive system 2NO2⇋2NO+O22NO_2 \leftrightharpoons 2NO + O_22NO2​⇋2NO+O2​ have been evaluated. In these calculations, the effect of pressure and temperature on the equilibrium constant, the dissociation of NO₂, NO and O₂ have been taken into account. Part 4: The first three sections of this part deal with the computation of thermodynamic properties of some industrially important substances. The last section deals with a note on surface tension and its temperature dependence.