Thermal instability and runaway criteria: The dangers of disregarding dynamics

Ball, Rowena; Gray, B.F.

doi:10.1016/j.psep.2012.05.008

Cited by 17 publications

(15 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In the application of FDI, many authors have confined their works to a simplified model in which the chemical reaction is not included (see References [15,16,[19][20][21][22]). However, there are many parameters which should be taken into consideration when a chemical reaction is introduced.…”

Section: Introductionmentioning

confidence: 99%

“…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.Processes 2019, 7, 454 2 of 20 essential to completely understand the dynamic characteristics of a new piece of equipment in terms of process safety [8,22] and further control. Like most cases, a cell-based model was used in this paper, i.e., each cell is modeled by means of energy and mass balances [23][24][25][26][27].…”

mentioning

confidence: 99%

See 1 more Smart Citation

Development of a Numerical Model for a Compact Intensified Heat-Exchanger/Reactor

Han

et al. 2019

Processes

View full text Add to dashboard Cite

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.Processes 2019, 7, 454 2 of 20 essential to completely understand the dynamic characteristics of a new piece of equipment in terms of process safety [8,22] and further control. Like most cases, a cell-based model was used in this paper, i.e., each cell is modeled by means of energy and mass balances [23][24][25][26][27]. The aim of this paper was to implement the concept of general modeling and validate it on a particular intensified HEX reactor which has already been studied at LGC (Laboratoire de Génie Chimique) [9]. During modeling, the thermal and hydrodynamic performances of the pilot under the condition of a chemical reaction which brings highly non-linear features were investigated. Once the detailed model is set up and validated, further research, for example on optimal control, adaptive control, fault diagnosis, and fault tolerant control could be carried out on it.The first part of this paper gives a brief description of the specific intensified HEX reactor. After that, mathematical equations, as well as model structure, are presented according to different parts of the pilot. In addition, parameters which were used to identify the heat transfer coefficient are identified using a genetic algorithm with some of the experimental data. Simulations were carried out in order to investigate the performance of the model. Considering the different aspects involved in the model (hydrodynamic, heat transfer, and reaction), the validation study was conducted in two parts: experiments with water and experiments with the highly exothermic reaction of sodium thiosulfate oxidation. Finally, the results of simulations and real experiments are compared in order to demonstrate the relevance and precision of the developed model.

show abstract

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

Development of a Numerical Model for a Compact Intensified Heat-Exchanger/Reactor

Han

et al. 2019

Processes

View full text Add to dashboard Cite

show abstract

“…Thus, the parametric sensitivity analysis allows identifying temperature maxima (hot spots) into the reactor and runaway criteria; while the dynamic one lets to track thermal stability, showing how the thermal behavior is changing under the variations of different operational parameters . It has already been demonstrated that dynamic analysis based on the singularity theory is a reliable tool to study exothermic reactive systems . It provides a useful framework for classifying branching phenomena in which different types of multiplicity of the nonlinear model can be found.…”

Section: Introductionmentioning

confidence: 99%

The application of dynamic modeling for thermal risks analysis of the acid‐catalyzed hydrolysis of glycidol

2016

View full text Add to dashboard Cite

The aim of this work was to determine the limits of safe operation of continuous flow stirred‐tank reactor (CSTR) for the acid‐catalyzed hydrolysis of glycidol. The stability analysis was performed by dynamic modelling. The obtained results were compared with the experimental data reported in the open literature. For this purpose, dimensionless variables and parameters were introduced and unstable material and energy balances were defined. The system equations were solved using Matcont (Matlab® software). Thus, bifurcation diagrams (in one and two dimensions) were mapped. All different dynamic states were identified and studied (thermal stability and instability, with unique and multiple solutions; Hopf bifurcations; turning points and envelope of periodic solutions). Finally, the intrinsic thermal unstable and cycle behavior of the acid‐catalyzed hydration of glycidol to produce glycerol was identified. The appropriate conditions to guarantee safe operation of CSTR were found. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4418–4426, 2016

show abstract

“…The main reasons are the nonlinear behaviour (Kvasnica et al, 2010), multiple steady states (Švandová et al, 2005), potential safety threats in reactors with exothermic chemical reactions (Ball and Gray, 2013) or presence of various uncertainties. Some of them arise from varying or not exactly known parameters, as e.g.…”

Section: Introductionmentioning

confidence: 99%

Robust MPC of an unstable chemical reactor using the nominal system optimization

Bakošová

Oravec

2014

Acta Chimica Slovaca

View full text Add to dashboard Cite

The continuous stirred-tank reactor with uncertain parameters was stabilized in the open-loop unstable steady state using the robust model predictive control. The gain matrices of the robust state-feedback controller were designed using the nominal system optimization and the quadratic parameter-dependent Lyapunov functions. The controller was verified by simulations using the non-linear model of the reactor and compared with the robust model predictive controller designed using the worst-case system optimization. The values of the quadratic cost function and the consumption of coolant were observed. Both robust model predictive controllers stabilized the reactor despite constrained control inputs and states. The robust model predictive control based on the nominal system optimization improved control responses and decreased the consumption of coolant.

show abstract

Thermal instability and runaway criteria: The dangers of disregarding dynamics

Cited by 17 publications

References 30 publications

Development of a Numerical Model for a Compact Intensified Heat-Exchanger/Reactor

Development of a Numerical Model for a Compact Intensified Heat-Exchanger/Reactor

The application of dynamic modeling for thermal risks analysis of the acid‐catalyzed hydrolysis of glycidol

Robust MPC of an unstable chemical reactor using the nominal system optimization

Contact Info

Product

Resources

About