Gilles Hétreux

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.

Use of an Object Oriented Dynamic Hybrid Simulator for the Monitoring of Industrial Processes

PrODHyS is a dynamic hybrid simulation environment, which offers extensible and reusable object oriented components dedicated to the modelling of processes. The purpose of this communication aims at presenting the main concepts of PrODHyS through the modelling and the simulation of a hydraulic system. Then, the feasible use of hybrid simulation in a supervision system is underlined. Copyright

Analysis of Operational Heat Exchanger Network Robustness via Interval Arithmetic

This work is part of the RREFlex project whose general objective is the development of robust software dedicated to the synthesis of flexible heat exchanger networks. This paper presents a methodology for analyzing the robustness of a Heat Exchanger Network (HEN) subject to fluctuations of process parameters (inlet temperature, heat transfer coefficient, etc.). It helps operational staff to locate sensitive streams and quantify the impact of these disturbances on the performance of the entire system. Based on a linear system and interval arithmetic, the computational effort is minimal and it allows the study of a great number of scenarios.

Dynamic hybrid simulation of batch processes driven by a scheduling module

Simulation is now a CAPE tool widely used by practicing engineers for process design and control. In particular, it allows various offline analyses to improve system performance such as productivity, energy efficiency, waste reduction, etc. In this framework, we have developed the dynamic hybrid simulation environment PrODHyS whose particularity is to provide general and reusable object-oriented components dedicated to the modeling of devices and operations found in chemical processes. Unlike continuous processes, the dynamic simulation of batch processes requires the execution of control recipes to achieve a set of production orders. For these reasons, PrODHyS is coupled to a scheduling module (ProSched) based on a MILP mathematical model in order to initialize various operational parameters and to ensure a proper completion of the simulation. This paper focuses on the procedure used to generate the simulation model corresponding to the realization of a scenario described through a particular scheduling.

Fault detection and isolation based on the model-based approach: Application on chemical processes

Abstract In this paper, we present a method for the fault detection and isolation based on the residual generation. The main idea is to reconstruct the outputs of the system from the measurement using the extended Kalman filter. The estimations are compared to the values of the reference model and so, deviations are interpreted as possible faults. The reference model is simulated by the dynamic hybrid simulator, PrODHyS. The use of this method is illustrated through an application in the field of chemical process.

Fault diagnosis and process monitoring through model-based and case based reasoning

In this paper, we present a method for the fault detection and isolation based on the residual generation coupled with a case based reasoning approach. The main idea is to reconstruct the outputs of the system from the measurement using the extended Kalman filter. The estimations completed with qualitative information are included in a Case Based Reasoning system in order to discriminate the possible faults and to have a reliable diagnosis. The reference model is simulated by the dynamic hybrid simulator, PrODHyS. The use of this method is illustrated through an application in the field of chemical process

Decision-making tool for scheduling of batch processes: the dynamic hybrid simulation kernel

Abstract PrODHyS is a dynamic hybrid simulation environment, which offers extensible and reusable object oriented components dedicated to the modeling of processes. The purpose of this communication is to illustrate the potentialities of PrODHyS through the use of hybrid simulation for the scheduling of semi-continuous processes.

Object-oriented components for dynamic hybrid simulation of a reactive distillation process

Abstract PrODHyS (Process Object Dynamic Hybrid Simulator ) is an object-oriented environment for the hybrid dynamic simulation of chemical processes. The aim of this paper is to introduce a small part of the main reusable object components available in this library and to illustrate its potentialities through the modeling and the simulation of a reactive distillation column.

Computer aided system for short term scheduling of batch processes based on hybrid simulation

Publisher Summary This chapter discusses the computer-aided system for the short-term scheduling of batch processes based on hybrid simulation. The hybrid simulator described is implemented in a software package. To meet the needs of batch-process scheduling, a global decision module has to be added. The work presented provides a first response against a type of implausibility often encountered in the schedule established by only simulation. Concerning the continuous aspect, it is envisaged to link the simulator to a general differential algebraic equation (DAE) integration module. This feature would allow the undertaking of more detailed and generic models of processes. Concerning the scheduling aspect, the second phase of the proposed method has to be developed to improve the final solution. It seems interesting to take into account set-up operations (such as cleaning operations) more precisely to reduce lost time in the decision-making module. In the case where the decision module cannot find a solution, some batches may be splitted into smaller batches and then a new simulation can be computed.