A heat-exchanger/reactor (HEX reactor) is a kind of plug-flow chemical reactor which combines high heat transfer ability and chemical performance. It is a compact reactor designed under the popular trend of process intensification in chemical engineering. Previous studies have investigated its characteristics experimentally. This paper aimed to develop a general numerical model of the HEX reactor for further control and diagnostic use. To achieve this, physical structure and hydrodynamic and thermal performance were studied. A typical exothermic reaction, which was used in experiments, is modeled in detail. Some of the experimental data without reaction were used for estimating the heat transfer coefficient by genetic algorithm. Finally, a non-linear numerical model of 255 calculating modules was developed on the Matlab/Simulink platform. Simulations of this model were done under conditions with and without chemical reactions. Results were compared with reserved experimental data to show its validity and accuracy. Thus, further research such as fault diagnosis and fault-tolerant control of this HEX reactor could be carried out based on this model. The modeling methodology specified in this paper is not restricted, and could also be used for other reactions and other sizes of HEX reactors.

-Vers une intensification des procédés économiquement viable : une nouvelle génération de réacteur-échangeur de chaleur-L'intensification des procédés (IP) constitue une des préoccupations majeures de l'industrie chimique. Parmi les nombreuses options possibles pour intensifier un procédé, lorsque le sujet concerne la sélectivité et l'échange thermique, la transposition d'un réacteur discontinu à un réacteur tubulaire continu paraît une bonne alternative. Dans ce contexte, le projet de R&D RAPIC consiste à développer un composant innovant à bas coût (environ 10 kg/heure). Ce projet porte sur la phase de conception, du niveau local au niveau global, et sur la phase de tests, depuis les maquettes élémentaires jusqu'aux essais pilote. Cet article propose une description détaillée de ce projet de recherche et présente les principaux résultats obtenus sur la définition et la spécification du canal de réaction, ainsi que les premières maquettes simples.

The intensified technologies offer new prospects for the development of hazardous chemical syntheses in safer conditions: the idea is to reduce the reaction volume by increasing the thermal performances and preferring the continuous mode to the batch one. In particular, the Open Plate Reactor (OPR) type ``reactor/exchanger" also including a modular block structure, matches these characteristics perfectly. The aim of this paper is to study the OPR behaviour during a normal operation, that is to say, after a stoppage of the circulation of the cooling fluid. So, an experiment was carried out, taking the oxidation of sodium thiosulfate with hydrogen peroxide as an example. The results obtained, in particular with regard to the evolution of the temperature profiles of the reaction medium as a function of time along the apparatus, are compared with those predicted by a dynamic simulator of the OPR. So, the average heat transfer coefficient regarding the ``utility" fluid is evaluated in conductive and natural convection modes, and then integrated in the simulator. The conclusion of this study is that, during a cooling failure, a heat transfer by natural convection would be added to the conduction, which contributes to the intrinsically safer character of the apparatus.

Numerous continuous intensified reactors are now accessible on the market that offer enhanced thermal performances in a continuous reactor. Such reactors are then particularly suited to fast and highly exothermic reactions. In this paper, the ability to also manage a slow and equilibrated system, the methyl acetate esterification reaction, on condition of intensification in terms of design and operating conditions is presented. To achieve this purpose, a new kinetics model has been developed and validated from experiments carried out in a lab scale batch reactor. Implemented in a simulation framework, this model leads to an intensified design of the reactor and the associated operating conditions. All this intensification methodology has been supported and validated by experimental studies.