Jerzy Szczygieł

Supercritical gas extraction of Polish brown coals

Abstract Properties of nine selected samples of Polish brown coals from both strip mines and perspective deposits varying in lithotype have been determined. This involved technical analysis of the elementary, group and petrographie compositions. The coals were extracted with supercritical toluene at 410 °C and 13 M Pa. The humic acid content and humodetrinite content were found to be well correlated with the yield of coal extract. The optimal conditions of gas extraction for a selected coal sample were determined.

Diffusion in a bidispersive grain of a reforming catalyst

Abstract An attempt is made to assess the effective coefficients of diffusion for the group components of a reforming mixture. The group components form in the interior of the catalyst grain. The equation proposed in this paper makes it possible to calculate the numerical values of these coefficients as a function of the parameters of the porous structure. On the basis of experimental data, a method is suggested for determining the efficiency of grain utilization. Some properties of bidispersive catalytic structures are analysed in more detail.

DFT modeling of CO2 adsorption on Cu, Zn, Ni, Pd/DOH zeolite.

This study is the analysis of the adsorption process of the CO2 molecule on the cationic sites of the DOH zeolite. Based on the DFT method, we have been able to identify several adsorption sites containing extra-framework cations and evaluate the value of the adsorption energy with respect to the distance from the adsorption site. The zinc cation has been found to cause the strongest interaction with the CO2 molecule. Subsequently, the adsorption process has been investigated by means of the Molecular Dynamics simulations. The results of the MD simulations are consistent with the geometry optimizations, and confirm the activation of CO2 molecule adsorbed in the Zn site.

Reaction of thiophene with hydrogen over CoMo/γ-Al2O3 catalysts. The role of cobalt.

Abstract The reaction of thiophene (T) and hydrogen on sulfided Mo/γ-Al2O3 and CoMo/γ-Al2O3 catalysts is described. The organic sulfur compounds were found in the product. The level of cobalt content in catalyst influences the composition of the products. Different types of active centers have been postulated.

Diffusion and kinetics of reaction over bidispersive reforming catalyst

The objective of the study was to construct a mathematical model for optimizing the porous structure of the reforming catalyst. Using a layered model of the catalyst grain and the kinetic scheme adopted for the process, equations were derived to describe the mass transport in the catalyst grain under conditions of reforming. Particular consideration was given to the problem of how the parameters of the porous structure affected the efficiency of the process. Substantiated was the favourable influence of an appropriate macropore (transport pore) proportion in the catalyst grain on the course of the process. The optimum quantitative ratio of wide to narrow pores in the catalyst grain was established for determined pore radii.

Reaction of thiophene with hydrogen over cobalt-molybdenum/γ-alumina catalysts. II: The kinetics of the reaction

Abstract The kinetics of the hydrogenolysis of thiophene on molybdenum/alumina and cobalt—molybdenum/alumina were studied in the temperature range 469–509 K and 583–623 K for hydrogen pressures of 0.10–1.81 MPa. Twenty-six rate equations of the Langmuir-Hinshelwood type were examined. The new kinetic equation for thiophene hydrogenolysis is proposed.

Mathematical analysis of the kinetics of hydrogenating depolymerization of benzene-insoluble coal extract fraction in the absence of catalyst

Abstract The paper analyses some kinetic models for the process of hydrogenating depolymerization of benzene-insoluble fractions of coal in the absence of a catalyst. Considerations as to the direction of decomposition of benzene-insoluble fractions to oils are presented.

GCMC simulations of CO2 adsorption on zeolite-supported Ir4 clusters.

We have studied the adsorption of CO2 molecules inside the pores of faujasite zeolite and evaluated the influence of the Ir4 clusters on the intensity of the adsorption. The force field designed for CO2 adsorption in zeolites has been extended with the parameters for the CO2/Ir4 interactions, taking the Density Functional Theory (DFT) energies as a reference. We have found that despite the fraction of the pore volume that is occupied by the Ir4 cluster, the adsorption is more intense than that of empty faujasite. The adsorption sites next to the cluster are very characteristic, and the interactions are more intensive due to the interactions of zeolite and the Ir cluster both playing an important role.

Mathematical analysis of hydrogenating depolymerization of asphaltenes from coal extracts

Abstract The mathematical analysis of hydrogenating depolymerization of asphaltenes from coal extracts is presented. The experiments were carried out in an autoclave in the presence of natural aluminosilicate with high content of iron at temperatures 673–733 K, and under hydrogen pressure 9.8–29.4 MPa. The parameters of the process have been optimized and suggestions regarding the conversion routes for asphaltenes formulated. An extensive depolymerization of asphaltenes into oils is possible in the presence of a disposable, natural aluminosilicate catalyst.

Statistical and mathematical analysis of the catalytic hydrogenating depolymerization of benzene-insoluble coal extract fraction

Abstract This Paper presents a statistical and mathematical analysis of hypotheses concerning the autoclave hydrogenating depolymerization of coal extract fractions insoluble in benzene. From comparison of theoretical and experimental data the most probable reaction mechanism was selected.