A numerical algorithm is presented for the filling process of a cylindrical column with equilateral cylinders. The process is based on simplified mechanics - the elements are added one by one until the mechanical equilibrium is reached. The final structure is examined with respect to the global and local porosity distribution. Oscillating radial porosity profile is obtained in accordance with experimental data.

Fixed beds were adopted for removal of organic dye from water by photocatalytic decomposition or adsorption. To this end, macroporous titania or silica micro-particles were synthesized from emulsions as micro-reactors and packed in the bed. During feeding aqueous methylene blue solution, UV light was irradiated for generation of active radicals for removal of dye by photocatalytic decomposition. Porous silica particles were also used as adsorbents in the bed for continuous adsorption of organic dye. For regeneration of the porous titania or silica particles, rinsing with fresh water was carried out before repeated cycles.

The development of efficient carbon dioxide sequestration and utilization technologies is an indispensable aspect of a wide range of measures directed at reducing the negative effects of anthropogenic emissions on the environment. One route is its capture via physical adsorption and further conversion to methane in the Sabatier reaction. The sorption process can be carried out, among others, in fixed-bed adsorptive reactors, in which the packing is made up of adsorbent and catalyst particles. Proper structuring of such a hybrid bed can contribute to increasing the efficiency of both stages of the process. Of importance in this regard is, first of all, the proper management of heat transfer. This study examines the sorption step of the operation of an adsorptive reactor for CO2 sequestration and methanation using a one-dimensional non-isothermal model of a layered fixed bed. Numerical calculations for different configurations and different volume adsorbent to catalyst ratios were carried out to determine how the hybrid structure of the bed and the atypical thermal waves it induces affect the sorption process. The results obtained prove that proper tailoring of the bed can be an excellent tool to control the temperature profiles and thus the performance of the apparatus and possibly its optimization.

The paper aims to show a search method for optimal conditions of 3A, 13X, ZSM-5 zeolite thermal regeneration after adsorption from a liquid water-isopropanol mixture. Comparative TGA-DTG results for heating of wet zeolites with different structure and hydrophobicity showed characteristic effects corresponding to the optimal temperature of zeolite regeneration. The consequences of overheating and collapse of the 3A, 13X, ZSM-5 zeolite structure at temperatures of 850, 900, 1000 °C, respectively, were recorded with XRD method. Moreover, XRD and NIR/DRS tests of loaded and regenerated zeolite samples showed interaction of adsorbate and co-adsorbed water with adsorbent and revealed influence of adsorption and regeneration processes on the adsorbent structure. Investigations of the regeneration of the zeolite 3A bed after adsorption of water from the isopropanol solution in the temperature swing adsorption (TSA) process were carried out by heating the bed with inert gas at 250 °C and different purge gas streams in the range of 1.68–2.40 kg/h. Four stages of wet bed regeneration were distinguished, which corresponded to the effect observed during TGA-DTG tests. For each stage, the specific demand for purge gas and energy was determined depending on the gas stream and its minimum value of 2.16 kg/h was indicated.

On the basis of hydrogen peroxide decomposition process occurring in the bioreactor with fixed-bed of commercial catalase the optimal feed temperature was determined. This feed temperature was obtained by maximizing the time-average substrate conversion under constant feed flow rate and temperature constraints. In calculations, convection-diffusion-reaction immobilized enzyme fixed-bed bioreactor described by a coupled mass and energy balances as well as general kinetic equation for rate of enzyme deactivation was taken into consideration. This model is based on kinetic, hydrodynamic and mass-transfer parameters estimated in earlier work. The simulation showed that in the biotransformation with thermal deactivation of catalase optimal feed temperature is only affected by kinetic parameters for enzyme deactivation and decreases with increasing value of activation energy for deactivation. When catalase undergoes parallel deactivation the optimal feed temperature is strongly dependent on hydrogen peroxide feed concentration, feed flow rate and diffusional resistances expressed by biocatalyst effectiveness factor. It has been shown that the more significant diffusional resistances and the higher hydrogen peroxide conversions, the higher the optimal feed temperature is expected.

Optimal feed temperature was determined for a non-isothermal fixed-bed reactor performing hydrogen peroxide decomposition by immobilized Terminox Ultra catalase. This feed temperature was obtained by maximizing the average substrate conversion under constant feed flow rate and temperature constraints. In calculations, convection-diffusion-reaction immobilized enzyme fixed-bed reactor described by a set of partial differential equations was taken into account. It was based on kinetic, hydrodynamic and mass transfer parameters previously obtained in the process of H2O2 decomposition. The simulation showed the optimal feed temperature to be strongly dependent on hydrogen peroxide concentration, feed flow rate and diffusional resistances expressed by biocatalyst effectiveness factor.