Mordechay Herskowitz

Using Sonochemical Methods for the Preparation of Mesoporous Materials and for the Deposition of Catalysts into the Mesopores

Ultrasound radiation can be used to synthesize a variety of mesporous materials. The reaction time is considerably shorter than the conventional methods. Ultrasonic waves can be further used for the insertion of amorphous nanosized catalysts into the mesopores. A detailed study demonstrates that the nanoparticles are deposited as a monolayer on the inner mesopores walls without blocking them. When the ultrasonically prepared catalyst/mesoporous-subtrate composite is used in catalysis a high conversion into product is obtained.

A simple approach to highly sensitive tubular reactors

The steady state operation of a long tubular fixed-bed reactor in which a single highly exothermic reaction is occurring is analyzed. To avoid temperature runaways, such reactors must be operated so that their temperature rises

Modelling of a trickle-bed reactor—the hydrogenation of xylose to xylitol

\Delta T

Wetting efficiency in trickle-bed reactors. The overall effectiveness factor of partially wetted catalyst particles

are small fractions of the adiabatic temperature rise

Silica-supported small crystals of ZSM-5 zeolite

\Delta T_{{\text{ad}}}

Runaway in highly sensitive tubular reactors

. So here asymptotic methods based on

Wetting efficiency in trickle-bed reactors: its effect on the reactor performance

\Delta T/\Delta T_{{\text{ad}}} \ll 1

Deep hydrodesulfurization of atmospheric gas oil; Effects of operating conditions and modelling by artificial neural network techniques

are used to determine the radial temperature and concentration profiles. A simple one-dimensional (z only) reactor model is then derived by substituting these asymptotically correct radial profiles into the full two-dimensional reactor equations and then averaging in r. By comparing with numerical solutions of the two-dimensional reactor equations, it is found that the one-dimensional model accurately simulates the two-dimensional equations, even in the highly sensitive runaway region. It is also shown that a runaway criterion derived from the model accurately predicts the runaway transition of the original two-dime...

Equilibrium Temperture profiles in highly sensitive tubular reactors

Modele de prediction de la conversion de xylose en xylitol dans un reacteur a ruissellement

Liquid-solid mass transfer in a trickle-bed reactor measured by means of a catalytic reaction

Abstract Expressions of the overall effectiveness factor as a function of the wetting efficiency, the Biot numbers for the gas liquid covered parts of the catalyst and the Thiele modulus have been developed for a slab, a cylinder and a sphere. The effect of particle shape on the overall effectiveness factor is discussed. Its significance over a wide range of wetting efficiencies, Biot numbers and Thiele moduli is pointed out.