No abstract

The new approach for simulation and optimization of a continuous catalytic regenerative (CCR) reformer process is proposed. Typical CCR reforming processes consist of three to four reactors with recycle. The reaction patterns and reactors are typically modeled using a system of partial differential equations (PDEs). The numerical simulation solution of the entire model for a process system consisting of multiple reaction zones with recycle is extremely time-consuming and, thus, impractical in optimization studies. That is why we proposed a more efficient simulation and optimization scheme based on quasi-steady-state assumptions. We define criteria for reactor fragmentation to avoid the introduction of large errors in the quasi-steady-state calculations. The optimization problem is formulated with the objective of minimizing fuel consumption. The employed objective function constitutes a combined measure for economic and environmental performance. It is shown that the proposed approach identifies considerable improvements for the process.

Densities, speeds of sound, and refractive indices of methyl laurate, ethyl laurate, ethyl myristate, and ethyl oleate in the temperature range 288.15−343.15 K and viscosities from 288.15 to 373.15 K were measured at atmospheric pressure. The measured properties were in good agreement with several available literature data, finding an overall absolute average percentage deviation (AAD) of 0.04%, 0.07%, 3%, and 0.1% for density, speed of sound, viscosity, and refractive index, respectively. The densities of mentioned esters were also measured along 15 isotherms from 293.15 to 413.15 K and at pressures up to 60 MPa using an Anton Paar DMA HP densimeter. Based on the literature data selected for comparison, in the studied ranges of temperature and pressure, the AADs of high-pressure densities were 0.08% for methyl laurate, 0.06% for ethyl laurate, and 0.05% for ethyl myristate. The obtained density values were correlated through the modified Tammann−Tait equation with an AAD lower than 0.009% for all the studied esters. The adjusted parameters were used to calculate the isothermal compressibility, isobaric thermal expansivity, internal pressure, and difference in isobaric and isochoric heat capacities. It was found that methyl laurate has higher density, speed of sound, and refractive index than ethyl laurate of the same fatty acid, while viscosities for the ethyl are slightly higher than those of the methyl laurate. The values of the isothermal compressibility and the isobaric thermal expansivity for ethyl laurate are slightly higher than those for methyl.

No abstract

Densities data of n-hexane, toluene and dichloromethane at temperatures 288.15-413.15 K and at pressures 0.1-60 MPa, determined in our previous work, were fitted to the modified Tait equation of state. The fitted temperature-pressure dependent density data were used to calculate the derived properties: the isothermal compressibility, the isobaric thermal expansivity, the difference between specific heat capacity at constant pressure and at constant volume and the internal pressure, over the entire temperature and pressure intervals specified above. In order to assess the proposed modeling procedure, a comparison of the obtained values for the isothermal compressibility and the isobaric thermal expansivity with the corresponding literature data were performed. The average absolute percentage deviations for isothermal compressibility were: for n-hexane 2.01-3.64%, for toluene 0.64-2.48% and for dichloromethane 1.81-3.20%; for the isobaric thermal expansivity: for n-hexane 1.31-4.17%, for toluene 0.71-2.45% and for dichloromethane 1.16-1.61%. By comparing the obtained deviations values with those found in the literature it can be concluded that the presented results agree good with the literature data. [Projekat Ministarstva nauke Republike Srbije, br. 172063]

No abstract

Densities, refractive indices, and viscosities of 1-amino-2-propanol (monoisopropanolamine (MIPA)) + 1-butanol and 1-amino-2-propanol + 2butanol solutions are reported over the entire range of mole fractions and the temperature range from (288.15 to 333.15) K. The Redlich−Kister relation was used for correlation of measured results of excess molar volumes, viscosities, and refractive indices as a function of temperature and composition. Partial molar volumes at infinite dilution were determined from apparent molar volumes. Negative values for excess molar volumes, refractive indices, and viscosity deviations are observed over the entire composition range. The viscosities of 1amino-2-propanol with 1-butanol and 1-amino-2-propanol with 2-butanol are well represented by an Arrhenius equation. Activation energies for viscous flows are determined by linearization of the Arrhenius equation, providing a clear explanation of the influence on hydrogen bonding. In order to confirm molecular interactions between compounds obtained by analysis of infinite dilution of solute, a FT-IR spectroscopy study was performed at T = 298.15 K. Interactional and structural effects were investigated through calculations of excess Gibbs free energy of activation of viscous flow.

No abstract