Publications de Albert Renken | EPFL Graph Search

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Background. The small characteristic sizes (in the range of 102 - 103 μm) of Microstructured reactors (MSR) lead to very high specific interfacial area which, in turn, increases heat- and mass transfer efficiency. However, for quasi instantaneous exothermic reactions, the overall reaction kinetics in MSR is strongly influenced by mixing. The characteristic time of the latter phenomenon varies from millisecond to seconds depending on the operating conditions used. If mixing is the rate determining step for h

This study addresses the development of a compact reactor for oxidative steam-reforming of methanol (OSRM) to produce hydrogen in autothermal mode for fuel cells. The string reactor uses catalytically active brass wires with a diameter of 500 mu m placed i ...

A non-thermal plasma rector with a catalytic electrode made of sintered metal fibres (SMFs) was tested for the oxidative decomposition of a model VOC toluene. The input energy was varied in the range 160-295 J/I by varying the applied voltage between 12.5 ...

Catalytic purification of air containing 250 ppm of toluene assisted by non-thermal plasma was carried out with a novel dielectric barrier discharge (DBD) reactor with an inner electrode made of sintered metal fibers (SMF). The optimization of the reactor ...

Small nanosized clusters of Co3O4 coated on PTFE (polytetrafluoroethylene) flexible film is reported as a novel supported photocatalyst effective in the fast discoloration of the azo-dye Orange II under simulated solar radiation in the presence of oxone (2 ...

Novel efficient structured combustion catalysts based on sintered metal fiber filters (MFF) were developed. To increase sp. surface area (SSA), metal fibers were coated by crack-free porous oxide films of SiO2, Al2O3, porous glass, and mesoporous SBA-15 silica. The composite materials presented uniform open macrostructure of the non-treated MFF filters and were suitable supports for deposition of catalytically active phases (Pd, Pt, and Co3O4). These catalysts were tested in hydrocarbon (CH4, C3H8) combusti

Ultrasound propagates through an elastic medium at a rate or speed named the ultrasound propagation velocity (UPV). This velocity is detd. by the rate at which the wave energy is transmitted, inversely related to the square root of the d. and compressibility of the medium. This technique is based on the increase of UPV with rising elasticity of the medium due to polymn. As monomer is transformed to polymer, both the d. and adiabatic compressibility change, making the UPV closely related to monomer conversio

Hydrogenation of 2-butyne-1,4-diol catalyzed by Pd nanoparticles on activated carbon fibers (ACFs) was studied. The ACF support in the form of woven fabrics provides the basis for structured catalytic fixed beds. In the present study, this catalyst was int ...

Hydrogen production by non-thermal plasma (NTP) assisted direct decomposition of hydrogen sulfide was carried out in a novel dielectric barrier discharge (DBD) reactor with the inner electrode made of sintered metal fibers (SMF) also functioning as catalys ...

Novel micro-structured string-reactor designed as catalytically active wires placed in parallel into a tube was developed. The small diam. of the channels (.apprx.100 mm) leads to a short radial diffusion time, a narrow residence time distribution, and a low pressure drop. This reactor was applied for the oxidative steam-reforming of methanol to produce hydrogen in autothermal mode for fuel cells. The heat generated during methanol oxidn. at the reactor entrance is axially transferred to the reactor zone of

Quasi-instantaneous exothermic reactions lead to the formation of unwanted hot spots even when carried out in conventional microstructured reactors (MSR) with tube diameter of 100 − 1000 μm. For this reason, alternative MSR designs are warranted to enable ...

Transient response and temperature-programmed desorption/reaction (TPD/TPR) methods were used to study the formation of adsorbed NOx from N2O and its effect during N2O decomposition to O2 and N2 over FeZSM-5 catalysts at temperatures below 653 K. The react ...

Detailed thermodynamic and kinetic study of the aqueous Kolbe-Schmitt synthesis of beta-resorcylic acid has been carried out in a laboratory-scale batch reactor operated under ambient pressure. The dependence of the conversion on partial pressure of carbon dioxide (4 x 10(-4) - 1 bar), initial concentration of resorcinol (0.4-0.8 M), initial concentration of potassium bicarbonate (0.4-6 M) and temperature (348-428 K) was studied. The reaction was found to be reversible and exothermic (Delta H = -30.4 kJ/mol

The low-pressure cold microwave (MW) plasma is shown as an efficient method to increase acidity of the ACF within less than 1 min treatment without affecting the fiber morphol. and strength. The ion-exchange capacity was 1.6 times higher compared to the no ...

The repetitive discoloration kinetics of the azo-dye Methyl Orange (taken as a model organic compound) was followed under solar simulated radiation (90 mW/cm2) to assess the performance of the TiO2/Tedlar® composite photocatalyst. The influence of solution ...

The kinetics and the mechanism of the selective reduction of nitric oxides (NOx) by hydrogen is studied on a trimetallic Pt–Mo–Co/a-Al2O3 catalyst under oxidising conditions. This system is interesting in view of an exhaust gas control of power plants or lean-burn cars. It can be shown that the NO dissociation is the crucial step, dominating the overall reaction behaviour and that it depends on temperature and on the partial pressure of H2. With increasing temperatures the reaction reveals an autocatalytic

A novel catalytic reactor with dielectric barrier discharge (DBD) at atmospheric pressure was developed for the abatement of volatile organic compounds (VOCs). The novelty of DBD reactor is the metallic catalyst serving also as the inner electrode. The cat ...

A review, with 89 refs., is presented on the subject of periodic operation of catalytic reactors by compn. forcing. Possible objectives of this mode of reactor operation are increased conversion, improved selectivity, reduced catalyst deactivation and insight into mechanisms of reactor models. Several forcing strategies may be used: manipulating one or more reactant concns., or interspersing pulses of inerts between pulses of reactants. These strategies are distinct from the variables in periodic operation,

The deactivation kinetics of a V/Ti oxide catalyst were studied in partial oxidn. of toluene to PhCHO and PhCO2H at 523-573 K. The catalyst consists of a monolayer of VOx species, and after oxidative pretreatment, contains isolated monomeric and polymeric metavanadate-like vanadia species under dehydrated conditions as was shown by FT Raman spectroscopy. Under the reaction conditions via in situ DRIFTS, fast formation of adsorbed carboxylate and benzoate species was obsd. accompanied by disappearance of the

A comprehensive review. The kinetics of various types of chem. reactions and the influence of transport processes on the effective reaction velocity (macrokinetics) are described. A survey is given on methods to det. the kinetics of reactions. Criteria for the selection and dimensioning of reactors and the choice of reaction conditions are discussed on the basis of reaction kinetics and with respect to efficiency, yield, and thermal safety. The behavior of reactors for single- and multi-phase systems is des

Albert Renken

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Effect of hot spots in microstructured reactors on product distribution during quasi-instantaneous exothermic reactions

Compact string reactor for authotermal hydrogen production

Catalytic non-thermal plasma reactor for abatement of toluene

Catalytic abatement of volatile organic compounds assisted by non-thermal plasma - Part II. Optimized catalytic electrode and operating conditions

Highly dispersed PTFE/Co3O4 flexible films as photocatalyst showing fast kinetic performance for the discoloration of azo-dyes under solar irradiation

Structured combustion catalysts based on sintered metal fibre filters

On-line conversion monitoring through ultrasound velocity measurements in bulk styrene polymerization in a recycle reactor - part I: experimental validation

Solvent-Free Selective Hydrogenation of 2-Butyne-1,4-diol over Structured Palladium Catalyst

Non-thermal plasma catalytic reactor for hydrogen production by direct decomposition of H2S

Micro-structured string-reactor for autothermal production of hydrogen

Multi-injection microstructured reactor for intensification of fast exothermic reactions: proof of concept

Role of adsorbed NO in N2O decomposition over iron containing ZSM-5 catalysts at low temperatures

Kinetic and thermodynamic study of the aqueous Kolbe–Schmitt synthesis of beta-resorcylic acid

Microwave plasma assisted preparation of Pd-nanoparticles with controlled dispersion on woven activated carbon fibres

Stabilization mechanism of TiO2 on flexible fluorocarbon films as a functional photocatalyst

Kinetics and mechanism of the reduction of NOx by H2 in oxygen - rich atmospheres on a Pt-Mo-Co / a-Al2O3 catalyst

Catalytic abatement of volatile organic compounds assisted by non-thermal plasma - Part 1. A novel dielectric barrier discharge reactor containing catalytic electrode

Periodic operation of catalytic reactors - introduction and overview

Deactivation kinetics of V/Ti-oxide in toluene partial oxidation

Chemical reaction technology