System Analysis and Simulation of the Process of Destructive Hydrogenization of Deasphaltisate of Heavy Oil

The article presents a systematic analysis and simulation of the process of destructive hydrogenation of deasphalted oil. The process of thermoregeneration of spent zeolite and the surface - acid properties of CaA zeolite catalysts are also studied. It has been established that such patterns that allow predicting their influence and to regulate the quality of the hydrogenation obtained on one or another form of the catalyst obtained from the studied factors and catalysts. In addition, the obtained data can be used in the search for the optimal process modes of the process under consideration on the specific form of the catalyst.

Theoretical Studies on the Mechanism of deNOx Process in Cu–Zn Bimetallic System—Comparison of FAU and MFI Zeolites

In the present study we propose a more promising catalyst for the deNOx process to eliminate harmful nitrogen oxides from the environment. The study was performed with a computer calculation using density functional theory (DFT) based on an ab initio method. Two zeolite catalysts, FAU and MFI, were selected with additional Cu–O–Zn bimetallic dimer adsorbed inside the pores of both zeolites. Based on the analysis of preliminary studies, the most probable way of co-adsorption of nitric oxide and ammonia was selected, which became the initial configuration for the reaction mechanism. Two types of mechanisms were proposed: with hydroxyl groups on a bridged position of the dimer or a hydroxyl group on one of the metal atoms of the dimer. Based on the results, it was determined that the FAU zeolite with a bimetallic dimer and an OH group on the zinc atom was the most efficient configuration with a relatively low energy barrier. The real advantage of the Cu–Zn system over FAU and MFI in hydrothermal conditions has been demonstrated in comparison to a conventional Cu–Cu catalyst.

Hydrodemethoxylation/Dealkylation on Bifunctional Nanosized Zeolite Beta

Mono-, and bimetallic Ni-, Ru-, and Pt-modified nanosized Beta zeolite catalysts were prepared by the post synthesis method and characterized by powder X-ray diffraction (XRD), nitrogen physisorption, HRTEM microscopy, temperature-programmed reduction (TPR-TGA), ATR FT-IR spectroscopy, and by solid-state MAS-NMR spectroscopy. The presence of nanosized nickel-oxide, ruthenium-oxide, and platinum species was detected on the catalysts. The presence of Brønsted and Lewis acid sites, and incorporation of nickel ions into zeolite lattice was proven by FT-IR of adsorbed pyridine. The structural changes in the catalyst matrix were investigated by solid state NMR spectroscopy. The catalysts were used in a gas-phase hydrodemethoxylation and dealkylation of 2-methoxy-4-propylphenol as a lignin derivative molecule for phenol synthesis.

Strikingly Distinctive NH3-SCR Behavior over Cu-SSZ-13 in the Presence of NO2

Commercial Cu-exchanged small-pore SSZ-13 (Cu-SSZ-13) zeolite catalysts are highly active for the selective catalytic reduction (SCR) of NOx with NH3, but distinct from other catalyst systems, their activity is unexpectedly inhibited in the presence of NO2. Here, we combined kinetic experiments, in-situ/operando X-ray absorption spectroscopy, and density functional theory (DFT) calculations to obtain direct evidence that under reaction conditions, strong oxidation by NO2 forces Cu ions to exist mainly as fixed framework Cu2+ species (fw-Cu2+), which impede the formation of dynamic binuclear Cu+ species that serve as the main active sites for the standard SCR (SSCR) reaction. As a result, the SSCR reaction is significantly inhibited by NO2 in the zeolite system, and the NO2-involved SCR reaction occurs with an energy barrier higher than that of the SSCR reaction on dynamic binuclear sites. Moreover, the NO2-involved SCR reaction tends to occur at the Brønsted acid sites (BAS) rather than the fw-Cu2+ sites. This work clearly explains the strikingly distinctive selective catalytic behavior in the zeolite system.

Bioisobutanol as a Promising Feedstock for Production of “Green” Hydrocarbons and Petrochemicals (A Review)

The existing approaches to bioisobutanol synthesis and commercial production are considered. Ways of using bioisobutanol as a component of motor fuel and as a promising feedstock for the production of “green” hydrocarbons and other petrochemicals that favor the progress of low-carbon economy are discussed. Particular attention is paid to catalytic processes of isobutanol conversion to isobutylene and butenes, aromatic hydrocarbons, C2–С4 olefins, and hydrogen-containing gases. Data on the mechanism of isobutanol transformations on zeolite catalysts are given.