AbstractsChemistry

This thesis is based on seven publications dealing with the Vapor Liquid Equilibrium (VLE) measurements which are necessary for pure components process. Two VLE measurements sections were comprised in this thesis. Firstly, VLE runs were conducted with a circulation still at both atmospheric pressure and isothermal conditions under low atmospheric pressure. Secondly, the static apparatus has been used in isothermal VLE for six binary pairs of C4 hydrocarbons and 2-propanone in a range from 69.6 kPa to 610.9 kPa. In addition, the VLE modeling was considered to determine the parameters in thermodynamic models. The selected components are in area of great industrial interest in view of developing gasoline additives to replace MTBE (2-methoxy-2-methylpropane), such as transform old MTBE plants to produce isooctene. Especially ETBE (2-Ethoxy-2-methylpropane) has emerged as an alternative to MTBE, because ETBE can be produced from ethanol made of renewable resources. The experimental data were correlated using activity coefficient models for the liquid phase and equation of state (EOS) for the vapor phase. These models were also compared with a predictive activity coefficient models. The estimations made with various different predictive coefficient models gave worse description of the measurements than by fitting the data with the Wilson equation. The experimental apparatus and the procedure presented were shown to be reliable, particularly the computer-controlled static apparatus. Moreover, these results seem to be reliable since they passed thermodynamic consistency tests. Most VLE and excess enthalpy measurements in this thesis are for binary systems that have not been measured previously.