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The feasibility of producing synthesis gas by the combination of partial oxidation and steam reforming of natural gas on a Pt-based catalyst in forced unsteady-state catalytic reactors has been considered by means of numerical simulations. A network of three reactors with periodical change of the feed position has been investigated as an alternative to the well-investigated reverse-flow reactor: these modes of reactor operation may lead to lower syngas manufacturing costs than the conventional unidirectional fixed-bed reactor because external heat exchangers are no longer required. A cyclic steady-state condition and autothermal behavior can be obtained by feeding low-temperature reactants. The influence of the main operating parameters (inlet temperature, switching time, inlet flow rate, and composition) on the performance of the device has been investigated, proving that the network can be competitive with traditional technologies, allowing for higher reactant conversion and product selectivity. The possibility of tailoring the H 2 /CO ratio to the value required for the production of methanol or Fischer-Tropsch synthesis has also been addressed.

Turbulent precipitation is an important topic in chemical reaction engineering because of its numerous industrial applications. Several modeling approaches have been used in the past, but in recent years, computational fluid dynamics (CFD) coupled with micromixing models has been successfully applied to predict the influence of mixing on the crystal size distribution (CSD). The micromixing model is generally based on the presumed probability density function (PDF) approach, such as finite-mode PDF or beta PDF, and the aim of this work is to compare presumed PDF predictions and full PDF predictions with experimental data. The experimental data were obtained from a tubular reactor in which turbulent precipitation of barium sulfate is carried out from aqueous solutions of barium chloride and sodium sulfate. The implementation of the presumed PDF model was done using FLUENT user-defined subroutines, whereas the full PDF calculations were carried out with an in-house code based on Monte Carlo methods using the flow field prediction from FLUENT. Turbulent precipitation is an important topic in chemical reaction engineering because of its numerous industrial applications. Several modeling approaches have been used in the past, but in recent years, computational fluid dynamics (CFD) coupled with micromixing models has been successfully applied to predict the influence of mixing on the crystal size distribution (CSD). The micromixing model is generally based on the presumed probability density function (PDF) approach, such as finite-mode PDF or beta PDF, and the aim of this work is to compare presumed PDF predictions and full PDF predictions with experimental data. The experimental data were obtained from a tubular reactor in which turbulent precipitation of barium sulfate is carried out from aqueous solutions of barium chloride and sodium sulfate. The implementation of the presumed PDF model was done using FLUENT user-defined subroutines, whereas the full PDF calculations were carried out with an in-house code based on Monte Carlo methods using the flow field prediction from FLUENT. Disciplines Chemical Engineering | Process Control and Systems Comments

The present paper presents the preliminary results of the ongoing Italian METERGLOB project on the contribution given by the exposed conductive parts to a Global Grounding System. One of the expected results of METERGLOB is to carry out guidelines for the identification of a Global Grounding System. These guidelines must be defined on the basis of the definitions and methods present in the current international standards on grounding and safety. In the paper some definitions and elements to be taken into account for the identification of a Global Grounding System are given