Les réseaux de neurones pour la modélisation et le contrôle du procédé d'évaporation : expérimentations et applications industrielles en sucrerie de canne

This research work, devoted to the synthesis of a neural network model based predictive command of a multiple-effect evaporation process, is in keeping with the continuation of the research works undertaken for several years within the Industrial Engineering Laboratory. The thesis consists in five chapters. The first one presents the evaporation stage in the production line, as well as both the theoretical and experimental developments required in order to identify a dynamic model of the plant. Chapter two lays the theoretical foundation of the technological transfer made up of the implementation of neural networks for the modelling and control of industrial processes. The first part of this technological transfer, described in chapter three, deals with the identification of evaporation process, as well as the simulation of identified models. These one has been identified using experimental data collected during measurement campaigns at the sugar factory of Bois-Rouge, Reunion Island, in 1997 and 1998. In chapter four, the problematic of the process control, confronted with the limits encountered by the traditional regulation schemes, warrant the implementation of a advanced control strategy. This approach, which makes up the second part of the technological transfer undertaken, leads us to the implementation of a mono variable predictive command scheme of the plant, based on a neural network model, which is tested through simulations in chapter five. The comprehensive results of the simulations are promising, which allows us to consider the implementation of a similar strategy in situ very soon.Ce travail de recherche, consacré à la synthèse d'une commande prédictive à modèle neuronal du procédé d'évaporation en multiple-effets, s'inscrit dans la continuité des travaux menés au L.G.I. depuis plusieurs années. Le mémoire de thèse s'articule en cinq chapitres : le premier présente l'atelier d'évaporation dans la chaîne de fabrication du sucre, et les développements théoriques et expérimentaux nécessaires à l'identification d'un modèle dynamique du procédé. Le chapitre 2 pose les bases théoriques du transfert technologique que constitue l'application des réseaux de neurones pour la modélisation et le contrôle des procédés industriels. La première partie de ce transfert technologique, décrite dans le chapitre 3, concerne l'identification de modèles du procédé d'évaporation, à partir de données expérimentales issues des campagnes de mesure menées à la sucrerie de Bois Rouge, La Réunion, en 1997 et 1998, et la simulation des modèles identifiés. Dans le chapitre 4, la problématique de l'automatisation du procédé, confrontée aux limites rencontrées par les schémas de régulation traditionnels, justifie la mise en oeuvre d'une stratégie de commande avancée. Cette démarche, qui constitue la deuxième partie du transfert technologique que nous avons entrepris, aboutit à la mise en oeuvre d'un schéma de commande prédictive mono variable basée sur un modèle à réseau de neurones, testé en simulation dans le chapitre 5. L'ensemble des résultats de simulation sont prometteurs, ce qui permet d'envisager l'implantation d'une stratégie similaire in situ dans les meilleurs délais

Assessment of medium and long term scenarios for the electrical autonomy in island territories: The Reunion Island case study

Island territories, due to their specific energy context, are at the forefront of energy transition studies with the aim of achieving energy autonomy. This is the case of Reunion Island, where the electricity mix is currently 70% carbon-based and where imports provide 80% of the energy consumption. In this context, this article assesses the facilities to install in the medium and long term to progressively reduce energy imports. Several scenarios of installed power generation capacities are studied for 2030 and 2050, associated with two scenarios for electricity consumption. Simulations are performed according these scenarios in order to define the electricity mix and the investments in new batteries and in the electricity transmission network reinforcement. For 2030, results show that a reduction in consumption compared with the trend could enable reduce costs and environmental impacts. For 2050, investments in new electricity generation technologies are essential to meet the needs of a 100% electrified vehicle fleet. If the overall consumption does not follow an energy demand management plan, all the energy sources on the island will have to be exploited to their maximum. The energy transition will also require large storage facilities and little reinforcement in the current electricity high voltage network

Modeling and Sizing of a Hydrogen Bus Refueling Infrastructure - A Case Study for Reunion Island

In order to achieve energy autonomy in island systems, the heavy mobility sector is considering hydrogen in order to reduce its dependence on fossil fuels and its emissions. This paper shows that hydrogen could be integrated on Reunion Island to decarbonise a fleet of 100 buses and assesses the impacts of such an integration. Through a novel methodology for the sizing of hydrogen refueling stations, the modelled stations are integrated into the island's overall electricity network. Three scenarios on the number of stations to be installed are presented in order to analyse their impact. The results show a total need of 7.6 MW of electrolyser, 5.3 MW of compressor and 951 kgH2 of hydrogen storage distributed among the installed stations. Installing four stations on the island would imply higher storage needs. The choice between installing two or three stations can be made according to cost, regulations or footprint criteria

A Novel Generic Diagnosis Algorithm in the Time Domain Representation

The health monitoring of a system remains a major issue for its lifetime preservation. In this paper, a novel fault diagnosis algorithm is proposed. The proposed diagnosis approach is based on a unique variable measurement in the time domain and manages to extract the system behavior evolution. The developed tool aims to be generic to several physical systems with low or high dynamic behavior. The algorithm is depicted in the present paper and two different applications are considered. The performance of the novel proposed approach is experimentally evaluated on a fan considering two different faulty conditions and on a proton exchange membrane fuel cell. The experimental results demonstrated the high efficiency of the proposed diagnosis tool. Indeed, the algorithm can discriminate the two faulty operation modes of the fan from a normal condition and also manages to identify the current system state of health. Regarding the fuel cell state of health, only two conditions are tested and the algorithm is able to detect the fault occurrence from a normal operating mode. Moreover, the very low computational cost of the proposed diagnosis tool makes it especially suitable to be implemented on a microcontroller

Intégration de l'hydrogène dans le réseau électrique de La Réunion : scénarios et impacts

International audience<font face="arial, helvetica"&gt<span style="font-size: 13px;"&gtLes îles françaises sont </span&gt</font&gt<span class="Object" role="link" id="OBJ_PREFIX_DWT2822_com_zimbra_date" style="color: rgb(0, 0, 0); font-family: arial, helvetica; font-size: 13px;"&gtaujourd’hui</span&gt<font face="arial, helvetica"&gt<span style="font-size: 13px;"&gt dépendantes à plus de 80% des imports d’énergies fossiles. Un des objectifs fixés par la loi relative à la Transition Energétique est leur autonomie énergétique d’ici 2030. Pour y parvenir, l’hydrogène pourrait être introduit localement, dans les véhicules lourds ou bien en stockage stationnaire. Le présent article évalue l’impact qu’aurait l’hydrogène sur le réseau électrique de l’île de La Réunion. Pour ce faire, un scénario de production et un de consommation électrique pour l’île en 2050 ont été développés. L’intégration d’un parc de véhicules individuels électrifié à 100 % a été considérée. De plus, une demande en hydrogène est introduite à cet horizon, en considérant un réseau de bus à pile à combustible. Afin d’étudier la place de l’hydrogène sur l’île à long terme, une modélisation du réseau électrique a été réalisée, suivi d’une optimisation mono-objectif. Les résultats obtenus montrent la pertinence d’installer des stockages hybrides batterie-hydrogène d’environ 60 MWh en soutien au réseau électrique. De plus, il est montré que seulement quelques lignes électriques seraient impactées à&nbsp;long terme, demandant des augmentations de puissance d’une dizaine de MVA.</span&gt</font&gt<div style="color: rgb(0, 0, 0); font-family: arial, helvetica; font-size: 13px;"&gt<br&gt</div&gt<div style=""&gt<div style=""&gt<font face="arial, helvetica"&gt<span style="font-size: 13px;"&gtABSTRACT - French islands are currently more than 80% dependent on imported fossil fuels. One of the objectives of&nbsp;</span&gt</font&gt<span style="font-size: 13px; font-family: arial, helvetica;"&gtthe French law on Energy Transition is their energy autonomy by 2030. To reach it, hydrogen could be introduced locally,&nbsp;</span&gt<span style="font-size: 13px; font-family: arial, helvetica;"&gtin heavy vehicles or in stationary storage. This article assesses the impact of hydrogen on the electrical grid of Reunion&nbsp;</span&gt<span style="font-size: 13px; font-family: arial, helvetica;"&gtIsland. To do so, one scenario of electricity production and one of electricity consumption for the island in 2050 have been&nbsp;</span&gt<span style="font-size: 13px; font-family: arial, helvetica;"&gtdevelopped. The integration of a fleet of individual vehicles electrified at 100% has been considered. In addition, a hydrogen&nbsp;</span&gt<span style="font-size: 13px; font-family: arial, helvetica;"&gtdemand is introduced at this horizon, considering a fuel cell bus network. In order to study the place of hydrogen on the&nbsp;</span&gt<span style="font-size: 13px; font-family: arial, helvetica;"&gtisland in the long term, a modelling of the electrical network was carried out, followed by a single-objective optimisation.&nbsp;</span&gt<span style="font-size: 13px; font-family: arial, helvetica;"&gtThe results obtained show the relevance to install hybrid battery-hydrogen storage of about 60MWh in support of the&nbsp;</span&gt<span style="font-size: 13px; font-family: arial, helvetica;"&gtelectrical network. Furthermore, it is shown that only a few power lines would be impacted in the long term, requiring&nbsp;</span&gt<span style="font-size: 13px; font-family: arial, helvetica;"&gtpower increases of about 10MVA.</span&gt</div&gt<div style=""&gt<br&gt</div&gt</div&g

Neural Model-Based Self-Tuning PID Strategy Applied to PEMFC

International audienceno abstrac

Soft-sensor for industrial sugar crystallization: On-line mass of crystals, concentration and purity measurement

International audienceThis paper deals with the design of a model-based soft-sensor to improve the process monitoring and control in industrial sugar crystallization. This soft-sensor is based on an original model dedicated to the last stage of crystallization, avoiding the solving of the population balance. Additional information like the mass of crystals in the solution, the concentration of dissolved sucrose and the purity are relevant to improve the manufacturing process. As these physicochemical properties are not measurable on-line, a model based soft-sensor is developed. The effectiveness of the soft sensor is demonstrated using real plant data from an industrial crystallization process

Accurate determination of parameters relationship for photovoltaic power output by augmented dickey fuller test and engle granger method

Power output from photovoltaic (PV) systems in outdoor conditions is substantially influenced by climatic parameters such as solar irradiance and temperature. PV manufacturers always provide technical specifications in laboratory conditions but reliable relationship for the power output must be determined for accurate prediction under real operating conditions. For the present study, solar irradiance G, temperature T and electrical power output P data under real conditions are methodically and regularly inscribed in dataloggers. Hence, in this paper, we investigate rigorous and robust statistical methods for small sample such as Augmented Dickey-Fuller and Engle Granger for stationary series to determine the estimate regression between variables P, G &amp; T. A first regression of power output P time series variable on solar irradiance G time series has shown spurious results and thus spurious regression. The first differences of such time series are stationary and a regression is proposed whereas temperature variable is identified as not significant and where autocorrelation of residuals is suspected. Finally, the novelty of this paper is the Engle &amp; Granger method that is used to provide a relationship between variables P and G in a difference level. A final relationship without suspicious heteroscedasticity has been determined. Our model is formulated on the basis of PV real conditions statistical approach and is more realistic than steady approach models

Non-linear PID control strategy using NN to improve the control of industrial sucrose crystallization

National audienceno abstrac