Abstract Asymmetric alumina hollow fibres produced by the phase inversion/sintering method present advantages in that high area/volume ratios and low mass transfer resistances are achieved due to the geometric configuration and the pore size distribution, respectively. Here we characterise hollow fibres that were prepared with different internal coagulants and at different sintering temperatures. Additionally, a palladium membrane was deposited on these different hollow fibres and hydrogen permeabilities through them were compared. More fingers were obtained when a mixture of solvent with water was used as internal coagulant, instead of pure water. At the same sintering temperature, nitrogen permeance through the fibre was increased 5-fold when a mixture of solvent and water was used as internal coagulant instead of pure solvent, and the water flux was increased 7-fold. The decrease in the sintering temperature increased the water permeance through the fibre from 21.4 to 63.9 L h-1 m-2 kPa-1, but decreased its mechanical strength from 74 to 41 MPa. The hydrogen permeance at 450 °C was increased from 5.54x10-5 to 3.06 x10-3 mol m-2 s-1 kPa-1 when using a more permeable hollow fibre as substrate. These results elucidate better conditions to fabricate hollow fibres that present low mass transfer resistances.

The objective of this study was to estimate thermodynamic data, such as standard enthalpy, entropy and Gibbs free energy changes of reaction and, consequently, chemical equilibrium constants, for a reaction system describing the hydrogen production from Liquefied Petroleum Gas (LPG). The acquisition of those properties was made using computational chemistry methods and the results were compared with experimental data reported in the literature. The reaction system of steam reforming of LPG was reported as a set of seven independent reactions involving the chemical species n-C4H10, C3H8, C2H6, C2H4, CH4, CO2, CO, H2O, H2 and solid carbon. Six computational approaches were used: Density Functional Theory (DFT) employing Becke's three parameter hybrid exchange functional, and the Lee-Yang-Parr correlation functional (B3LYP) using the 6-31G++(d,p) basis set and the composite methods CBS-QB3, Gaussian-1 (G1), Gaussian-2 (G2), Gaussian-3 (G3) and Gaussian-4 (G4). Mole fractions of the system components were also determined between 873.15 and 1173.15 K, at 1 atm and a feed with a stoichiometric amount of water. Results showed that the hybrid functional B3LYP/6-31G++(d,p), G3 and G4 theories were the most appropriated methods to predict the properties of interest. Gaussian-3 and Gaussian-4 theories are expected to be good thermodynamic data predictors and the known efficient prediction of vibrational frequencies by B3LYP is probably the source of the good agreement found in this study. This last methodology is of special interest since it presents low computational cost, which is important when more complex molecular systems are considered.

In this paper, a novel approach for establishing the route for process intensification through the application of two developed softwares to characterize reactive mixtures is presented. A robust algorithm was developed to build up reactive phase diagrams and to predict the existence and the location of reactive azeotropes. The proposed algorithm does not depend on initial estimates and is able to compute all reactive azeotropes present in the mixture. It also allows verifying if there are no azeotropes, which are the major troubles in this kind of programming. An additional software was developed in order to calculate reactive residue curve maps. Results obtained with the developed program were compared with the published in the literature for several mixtures, showing the efficiency and robustness of the developed softwares.