Surveillance des Systèmes Dynamiques Hybrides : Application aux procédés

Ces travaux présentent une méthodologie de détection et localisation de défauts pour la surveillance des Systèmes Dynamiques Hybrides. La méthodologie développée repose sur une approche mixte qui combine une méthode à base de modèles pour la détection de fautes et une approche à partir de données de reconnaissance de formes pour l’indentification de la ou les faute(s). Elle se décompose en trois grandes étapes :\ud - La première étape consiste en la reconstruction de l’état à partir d’un filtre de Kalman étendu et en la génération de résidus par comparaison de l’état reconstruit à celui obtenu par la simulation en parallèle du modèle de référence ;\ud - La seconde étape réside dans l’exploitation des résidus générés précédemment pour la construction d’une structure plus complexe, les signatures (non binaires);\ud - La troisième et dernière étape s’apparente à la résolution d’un problème de reconnaissance de formes dans lequel la signature générée est comparée à une matrice d’incidence (signatures de défauts théoriques) au sens d’une distance.\ud Cette approche a été intégrée au sein de la plate-forme de simulation PrODHyS, au travers du développement du module PrODHySAEM. Son utilisation est illustrée par l’étude de problèmes de diagnostic dans le domaine des procédés. ________________________________________________________________________________________ These works present a fault detection and isolation methodology for the monitoring of Hybrid Dynamic Systems. The developed methodology rests on a mixed approach which combines a model-based method for the fault detection and an approach based on data (pattern matching) for the identification of fault(s). It is divided into three parts :\ud - The first part concerns the reconstruction of the state of the system, thanks to the Extended Kalman Filter and the generation of the residuals by comparison between the predicted behavior (obtained thanks to the simulation of the reference model) and the real observed behavior (estimated by the Extended Kalman Filter). \ud - The second part exploits these residuals for the generation of a complex structure: the non binary signatures. \ud - The last part deals with the diagnosis of the fault and is based on a problem of pattern matching: the signature obtained in the previous part is compared with the theoretical fault signatures by means of distance. \ud This methodology is integrated within the simulation platform PrODHyS, through the development of the module PrODHySAEM. Its use is illustrated by the studies of diagnosis problems in the field of Chemical Process System Engineering.\ud \u

Model based fault diagnosis for hybrid systems : application on chemical processes

The complexity and the size of the industrial chemical processes induce the monitoring of a growing number of process variables. Their knowledge is generally based on the measurements of system variables and on the physico-chemical models of the process. Nevertheless, this information is imprecise because of process and measurement noise. So the research ways aim at developing new and more powerful techniques for the detection of process fault. In this work, we present a method for the fault detection based on the comparison between the real system and the reference model evolution generated by the extended Kalman filter. The reference model is simulated by the dynamic hybrid simulator, PrODHyS. It is a general object-oriented environment which provides common and reusable components designed for the development and the management of dynamic simulation of industrial systems. The use of this method is illustrated through a didactic example relating to the field of Chemical Process System Engineering

Towards the modelling of a heat-exchanger reactor by a dynamic approach

The aim of this paper is to present the development of a simulation tool in order to assess the inherently safe characteristics of a heat‐exchanger reactor(HEX) operating reaction systems. The modelling of steady and transient states of a HEX reactor is performed following a hybrid dynamic approach. The global dynamic behaviour of this reactor can be represented by several continuous models, which are bounded by state or time events. Each continuous model is defined as a system of partial differential‐algebraic equations. The numerical scheme is based on the method of lines. Special attention is paid to the model initialization and a simulation strategy of the start‐up phase is presented. The validation of the model is made by numerous examples, such as the simulation of an exothermic reaction

Safety enhancement by transposition of the nitration of toluene from semi-batch reactor to continuous intensified heat exchanger reactor

The behaviour of a continuous intensified heat exchanger (HEX) reactor in case of process failure is analysed and compared to the behaviour of a semi-continuous reactor. The nitration of toluene is considered as test reaction to identify the main failure scenarios that can lead to thermal runaway in both processes using the HAZOP method.No flow rate of process fluid and utility fluid in the continuous process. No stirring during feeding of the reactor followed by normal stirring for the semi-continuous reactor. These scenarios are simulated for both processes and the temperature profiles are observed. This study shows that the temperature is better controlled in the continuous process because of the intrinsic characteristics of the HEX reactor. In fact, this device has a low reactive volume relative to the mass of the reactor, allowing a good dissipation of the heat produced by the reaction, even in case of failure. This characteristic of the intensified reactor is confirmed by an experimental work

Integration of a failure monitoring within a hybrid dynamic simulation environment

The complexity and the size of the industrial chemical processes induce the monitoring of a growing number of process variables. Their knowledge is generally based on the measurements of system variables and on the physico-chemical models of the process. Nevertheless this information is imprecise because of process and measurement noise. So the research ways aim at developing new and more powerful techniques for the detection of process fault. In this work, we present a method for the fault detection based on the comparison between the real system and the reference model evolution generated by the extended Kalman filter. The reference model is simulated by the dynamic hybrid simulator, PrODHyS. It is a general object-oriented environment which provides common and reusable components designed for the development and the management of dynamic simulation of industrial systems. The use of this method is illustrated through a didactic example relating to the field of Chemical Process System Engineering

Dynamic Simulation for Risk Analysis : Application to an Exothermic Reaction

Currently, there is a strong demand for quantitative process risk analysis. There is a challenge in describing the process dynamic behaviour in case of failures. We suggest a methodology that combines dynamic simulation (Aspen Plus Dynamics tool), risk analysis (HAZOP review) and risk matrices. The hazardous scenarios leading to major accidents are identified, some of them are simulated which allows the determination of consequences and quantification of severity. Moreover, the knowledge of the process dynamic behaviour and the evolution of the operating parameters during a degraded mode permits adequate safety barriers recommendation. In this paper, the aim is to apply this methodology to a case study concerning an exothermic reaction in a semi-batch reactor. The chosen reaction is the oxidation reaction of sodium thiosulphate by hydrogen peroxide. Advantages and limitations of the proposed approach are revealed and discussed

Towards an organizational and socio-technical context-aware adaptation of emergency plans

International audienceIn France, facilities listed under environment protection regulations are required to draw up emergency plans. During a crisis situation, facing an unexpected event, these plans may be irrelevant. They have to be adapted to the current crisis situation and its observed or anticipated evolutions, using data emitted by the crisis ecosystem. But this adaptation requires lots of effort and is time-consuming. This article aims at presenting an approach to ensure the dynamic adaptation of emergency plans. We propose to identify generic configuration variables (representing interactions of physical phenomena and human factors on the facility) and to feed these configuration variables by collecting and processing data emitted by sensors, social networks, official reports, etc. Therefore, emergency plans could natively integrate agility by their ability to detect and take into account a change in the crisis situation and decision makers will be supported since the early stage of the crisis respons

De la simulation dynamique hybride vers la conduite de procédés batch et semi-continus.

PrODHyS est un environnement de simulation dynamique hybride dont la particularité est de fournir des composants orientés objets généraux et réutilisables pour la modélisation d'appareils et d'opérations présents dans les procédés industriels. Les grands principes sur lesquels est fondé PrODHyS sont d'abord exposés en développant plus particulièrement les aspects relatifs au niveau commande. Ces concepts sont ensuite illustrés à travers la simulation d'un exemple académique de procédé batch permettant d'illustrer les potentialités du simulateur. Enfin, la dernière partie aborde brièvement des travaux en cours montrant l'exploitation de ce simulateur pour la conduite de ce type de procédés (ordonnancement et supervision)