Ni-Rhodanine Complex Supported on FSM-16 as Mesoporous Silica Support: Synthesis,Characterization and Application in Synthesis of Tri and Tetrasubstituted Imidazoles and 3,4-Dihydropyrimidine-2-(1H)-Ones

A new, efficient and recoverable heterogeneous catalyst was successfully synthesized by functionalization of mesoporous silica FSM-16. The FSM-16/CPTMS-Rh-     

A pore-scale model for microfibrous ammonia cracking microreactors via lattice Boltzmann method

Microfibrous microreactors with high reactive surface-to-volume ratio are good choices for ammonia cracking, which is one of the main strategies for CO-free hydrogen production. In the current study, a numerical model based on the lattice Boltzmann method (LBM) is presented to investigate ammonia cracking microreactors with coupled physiochemical thermal processes at the pore scale. Several sets of transport phenomena such as fluid flow, species transport, heat transfer and chemical reaction are taken into account. Moreover, to model the species transport in the ammonia cracking microreactor an active approach is applied for the first time. The model is validated and then employed to simulate the reactive transport in five different microreactors with dissimilar structural parameters. Comparison of the results shows that the fibers orientation is an effective geometric parameter that can greatly influence the hydrogen production efficiency.     

Shift catalysts in biomass generated synthesis gas

One of the CHRISGAS project objectives is to study the shift catalysts in biomass-generated synthesis gas. The water gas shift reaction is ruled by equilibrium, and the state of the gas can for a given H₂/CO ratio be shifted by addition/removal of water, CO₂ and/or by a change in the temperature. Stability area in respect to gas composition, sulphur content, pressure and temperature for FeCr shift catalyst has been investigated by thermodynamic equilibrium calculations. The calculations show that carbide formation is favourable in the “Normal water” case without sulphur in the gas. If sulphur is present in the gas, the situation improves due to sulphide formation.     

The release of organic compounds during biomass drying depends upon the feedstock and/or altering drying heating medium

The release of organic compounds during the drying of biomass is a potential environmental problem, it may contribute to air pollution or eutrophication. In many countries there are legal restrictions on the amounts of terpenes that may be released into the atmosphere. When considering bioenergy in future energy systems, it is important that information on the environmental effects is available. The emissions of organic compounds from different green and dried biofuels that have been dried in hot air and steam medium, were analyzed by using different techniques. Gas chromatography and gas chromatography mass spectrometry have been used to identify the organic matter. The terpene content was significantly affected by the following factors: changing of the drying medium and the way the same biomass was handled from different localities in Sweden. Comparison between spectra from dried and green fuels reveal that the main compounds emitted during drying are monoterpene and sesquiterpene hydrocarbons, while the emissions of diterpene hydrocarbons seem to be negligible. The relative proportionality between emitted monoterpene, diterpene and sesquiterpene change when the drying medium shifts from steam to hot air. The obtained result of this work implies a parameter optimization study of the dryer with regard to environmental impact. With assistance of this result it might be foreseen that choice of special drying medium, diversity of biomass and low temperature reduce the emissions. A thermo-gravimetric analyzer was used for investigating the biomass drying rate.     

Catalytic properties of oxide nanoparticles applied in gas sensors

A series of gas sensing layers based on indium oxide doped with gold were prepared by using the aerosol technology for deposition as the active contact layer in a metal oxide semiconductor capacitive device. The interaction between the measured species and the insulator surface was quantified as the voltage changes at a constant capacitance of the device. The sensor properties were investigated in the presence of H₂, CO, NH₃, NO, NO₂ and C₃H₆ at temperatures between 100–400 °C. Significant differences in the morphology of the layer and its sensitivity were noted for different preparation methods and different gas environments.     

Deactivation of Pt/wire-mesh and vanadia/monolith catalysts applied in selective catalytic reduction of NO<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> in flue gas

In this study the deactivation of Pt/wire mesh and vanadia/monolith catalysts by aerosol particles of some inorganic salts (K₂SO₄, KCl and ZnCl₂) with high or low melting points has been investigated. The aerosol particles may either diffuse within the matrix of the catalysts and block the mezzo and micro pores, or deposit on the outer surface of the catalysts and form a porous layer causing a mass transfer resistance that ultimately deactivates the catalysts. It has been observed that in both Pt/wire mesh and vanadia/monolith catalysts the deactivation effect of ZnCl₂ was more pronouced compared to other salts. As an example, after 31 hours of exposure to ZnCl₂, 10% of the catalysts activities was lost. This may be related to the ZnCl₂ lower melting point in comparison with other poisons. These results are in agreement with the previous findings for deactivation of wire-mesh catalysts used for oxidation of volatile organic compounds (VOC) and CO by exposing the catalysts to the aerosols generated from inorganic salts.     

The Investigation of Vertical Wells' Optimum Two-phase Flow Empirical Correlation for the Ab-Teymour Reservoir

Abstract

There are different procedures for predicting pressure drop in two-phase flow pipelines. However, for each reservoir one or two correlations or mechanistic models give more accurate results. The authors investigated various correlations and mechanistic models in order to match fluid pressure losses considering all parameters such as friction, liquid holdup, superficial velocities, densities, viscosities, and interfacial tension. Commercial software, Pipesim, was used to simulate the fluid pressure losses. Drift flux modeling for predicting pressure profile was also investigated. A program for calculating pressure drops and average deviation of calculated pressures using this drift flux model was developed and the results were compared with other correlations.     

The technical feasibility of biomass gasification for hydrogen production

Biomass gasification for energy or hydrogen production is a field in continuous evolution, due to the fact that biomass is a renewable and CO₂ neutral source. The ability to produce biomass-derived vehicle fuel on a large scale will help to reduce greenhouse gas and pollution, increase the security of European energy supplies, and enhance the use of renewable energy. The Värnamo Biomass Gassification Centre in Sweden is a unique plant and an important site for the development of innovative technologies for biomass transformation. At the moment, the Värnamo plant is the heart of the CHRISGAS European project, that aims to convert the produced gas for further upgrading to liquid fuels as dimethyl ether (DME), methanol or Fischer–Tropsch (F–T) derived diesel. The present work is an attempt to highlight the conditions for the reforming unit and the problems related to working with streams having high contents of sulphur and alkali metals.     

Investigation of the corrosion behavior of cathodic arc evaporated stainless steel coating in 3.5% NaCl

In this paper, two major technical problems (growth defects and chromium content loss) encountering when cathodic arc evaporation physical vapor deposition (CAE-PVD) was used for deposition of stainless steel and their subsequent effects on corrosion behavior of the coating in 3.5 wt % NaCl solution have been investigated. Growth defects in spherical and needle-like shapes were the common defects that resulted from CAE-PVD of a stainless steel and played a major role in determining the corrosion behavior of the coating. The results showed a composition difference between the coating matrix (with ~11 at % Cr) and the growth defects, particularly needle-like ones (with ~15 at % Cr). According to SEM images, it seemed that the needle-like defects were passivated and were susceptible to pitting corrosion while coating matrix was corroded. The results also showed that the corrosion of the coating was influenced by two factors: building up micro-galvanic cells between the needle-like defects (as passivated regions) and both coating matrix and the spherical defects (as active sites). In addition, an intense localized corrosion (as micro-crevice corrosion) was observed around the growth defects.