AKTS Software Technical Comments

Thermal decomposition of AIBN, Part B: Simulation of SADT value based on DSC results and large scale tests according to conventional and new kinetic merging approach

B. Roduit1, M. Hartmann1, P. Folly2 A. Sarbach2, P. Brodard3, R. Baltensperger3

1AKTS AG, TECHNOArk 1, 3960 Siders, Switzerland, http://www.akts.com
2armasuisse, Science and Technology Centre, 3602 Thun, Switzerland, http://www.armasuisse.ch
3University of Applied Sciences of Western Switzerland, Bd de Prolles 80, 1705 Fribourg, Switzerland, http://www.eia-fr.ch


Abstract

The paper presents the results of the common project performed with the Federal Institute for Materials Research and Testing, Berlin, Germany (BAM) concerning the comparison of the experimental results with simulations based on the application of the kinetic-based method and heat balance of the system for the determination of the self accelerating decomposition temperature (SADT). The substantial potential of the kinetic-based method is illustrated by the results of the simulation of SADT of azobisisobutyronitrile (AIBN). The influence of sample mass and overall heat transfer coefficient on the SADT values were simulated and discussed. Simulated SADT values were verified experimentally with a series of large-scale experiments (UN test H.1 [1]) performed with packaging of 5, 20 and 50 kg of AIBN in an oven at constant temperatures. Additionally, the results of small-scale test H.4 for SADT determination based on the heat loss similarity as described in details in the UN Manual [1] were compared with the simulated data based on kinetic approach. The paper presents also the basic principles of a new kinetic analysis workflow in which the heat flow traces (e.g., DSC) are simultaneously considered with results of large-scale tests as e.g., H.1 or H.4. Application of the newly proposed kinetic workflow may increase accuracy of simulations of SADT based on results collected in the mg-scale and considerably decrease the amount of expensive and time consuming experiments in kg-scale tests.

View Study: Thermochimica Acta, Vol. 621 (2015), 6-24
http://dx.doi.org/10.1016/j.tca.2015.06.014

Determination of Thermal Hazard from DSC measurements. Investigation of Self-Accelerating Decomposition Temperature (SADT) of AIBN

B. Roduit1, M. Hartmann1, P. Folly2 A. Sarbach2, P. Brodard3, R. Baltensperger3

1AKTS AG, TECHNOArk 1, 3960 Siders, Switzerland, http://www.akts.com
2armasuisse, Science and Technology Centre, 3602 Thun, Switzerland, http://www.armasuisse.ch
3University of Applied Sciences of Western Switzerland, Bd de Prolles 80, 1705 Fribourg, Switzerland, http://www.eia-fr.ch


Abstract

The method of determination of the thermal hazard properties of reactive chemicals from DSC experiments is illustrated by the results of SADT simulations performed with azobisisobutyronitrile (AIBN). The kinetics of decomposition of AIBN in the solid state was investigated in a narrow temperature window of 7294 C, just below the sample melting. The kinetic parameters of the decomposition were evaluated by differential isoconversional method. The very good fit of the experimental results by the simulation curves, based on the determined kinetic parameters, indicated the correctness of the kinetic description of the process. Application of the kinetic parameters, together with the heat balance performed by numerical analysis, allowed scale-up of thermal behaviour from mg- to kg-scale and simulation of SADT. The study presents the evaluation of the influence of the overall heat transfer coefficient U on the SADT value. The results obtained clearly illustrate also the dependence of SADT on the sample mass. The tenfold increase of the mass from 5 to 50 kg results in the decrease of the SADT from 50 to 43 C. Determination of the reaction kinetics, describing the rate of heat generation, and the heat balance in the system, based on Frank-Kamenetskii approach, was calculated using AKTS Thermokinetics and Thermal Safety software.

View Study: Journal of Thermal Analysis and Calorimetry, Vol. 117 (2014), 1017-1026
http://link.springer.com/article/10.1007/s10973-014-3903-3

 


 

Estimation of Time to Maximum Rate under Adiabatic Conditions(TMRad) using Kinetic Parameters derived from DSC - Investigation of Thermal Behavior of 3-Methyl-4-Nitrophenol

Bertrand Roduit1, Patrick Folly2, Alexandre Sarbach2, Beat Berger2, Franz Brogli3, Francesco
Mascarello4, Mischa Schwaninger4, Thomas Glarner5, Eberhard Irle6, Fritz Tobler6, Jacques Wiss7,
Markus Luginbühl8, Craig Williams8, Pierre Reuse2, Francis Stoessel9

1AKTS AG, TECHNOArk 1, 3960 Siders, Switzerland, http://www.akts.com
2armasuisse, Science and Technology Centre, 3602 Thun, Switzerland
3Ciba Schweizerhalle AG, P.O. Box, 4002 Basel, Switzerland
4DSM Nutritional Products Ltd., Safety laboratory, 4334 Sisseln, Switzerland
5F. Hoffmann-La Roche Ltd, Safety laboratories, 4070 Basel, Switzerland
6Lonza AG, Safety Laboratory Visp, Rottenstr. 6, 3930 Visp, Switzerland
7Novartis Pharma AG, Novartis Campus, WSJ-145.8.54, 4002 Basel, Switzerland
8Syngenta Crop Protection Münchwilen AG, WMU 3120.1.54, 4333 Münchwilen, Switzerland
9Swiss Safety Institute, Schwarzwaldallee 215, WRO-1055.5.02, 4002 Basel, Switzerland


Abstract

Kinetic parameters of the decomposition of hazardous chemicals can be applied for the estimation of their thermal behavior under any temperature profile. Presented paper describes the application of the advanced kinetic approach for the determination of the thermal behavior also under adiabatic conditions occurring e.g. in batch reactors in case of cooling failure. The kinetics of the decomposition of different samples (different manufacturers and batches) of 3-methyl-4-nitrophenol were investigated by conventional DSC in non-isothermal (few heating rates varying from 0.25 to 8.0 K/min) and isothermal (range of 200-260°C) modes. The kinetic parameters obtained with AKTS-Thermokinetics Software were applied for calculating reaction rate and progress under different heating rates and temperatures and verified by comparing simulated and experimental signals. After application of the heat balance to compare the amount of heat generated during reaction and its removal from the system, the knowledge of reaction rate at any temperature profiles allowed the determination of the temperature increase due to the self-heating in adiabatic and pseudo-adiabatic conditions.
Applied advanced kinetic approach allowed simulation the course of the Heat-Wait-Search (HWS) mode of operation of adiabatic calorimeters. The thermal safety diagram depicting dependence of Time to Maximum Rate (TMR) on the initial temperature was calculated and compared with the results of HWS experiments carried out in the system with F-factor amounting to 3.2. The influence of the F-factor and reaction progress reached at the end of the HWS monitoring on the TMR is discussed. Presented calculations clearly indicate that even very minor reaction progress reduces the TMRad of 24 hrs characteristic for a sample with initial reaction progress amounting to zero.
Described estimation method can be verified by just one HWS-ARC, or by one correctly chosen ISO-ARC run of reasonable duration by knowing in advance the dependence of the TMR on the initial temperature for any F-factor. Proposed procedure results in significant shortening of the measuring time compared to a safety hazard approach based on series of ARC experiments carried out at the beginning of a process safety evaluation.

View Study (pdf, 755 KB)

View Poster (pdf, 294 KB)

 


 

Scale-up Based on Advanced Kinetics. Influence of DTBP/Toluene Ratio on the Thermal Behavior of Samples in mg, kg and ton-Scales

B. Roduit1, M. Hartmann1, S. Kaneko2, P. Folly3, P. Brodard4, S- Gomez4, R. Marti4, J.-N. Aebischer4

1AKTS AG, TECHNOArk 1, 3960 Siders, Switzerland, http://www.akts.com
2Palmetrics Corp., ?350-1328, Hirose-dai 2-16-15, Sayama city, Japan, http://www.palmetrics.co.jp
3armasuisse, Science and Technology Centre, 3602 Thun, Switzerland, http://www.armasuisse.ch
4University of Applied Sciences of Western Switzerland, Bd de Prolles 80, 1705 Fribourg, Switzerland, http://www.eia-fr.ch


Abstract

The runaway reactions are generally investigated by the time-consuming Accelerating Rate Calorimetry (ARC) or in isothermal (ISO-ARC) or heat-waitsearch (HWS) modes. In present poster we discuss the application of the Differential Scanning Calorimetry (DSC) for the determination of the Time to Maximum Rate under adiabatic conditions (TMRad) of various concentrations of Ditert- butyl peroxide (DTBP) in toluene. Additionally we present the method of simulation of the course of ARC experiments. We propose an advanced elaboration of the DSC data leading to the determination of the kinetic parameters of investigated reactions which, in turn, allows the simulation of the reaction course under any temperature mode. These kinetic parameters obtained in mg-scale considered simultaneously with a heat balance give a powerful tool for the prediction of the thermal behaviour of the substance in kg-scale (pseudo-adiabatic conditions: SADT, cook-off) or in ton-scale (adiabatic conditions: TMRad).

View poster (pdf, 411 KB)

 


 

Kinetic Evaluations for the Transportation of Dangerous Chemical Compounds

Marco Dellavedova1, Christian Pasturenzi1,Lucia Gigante1, Angelo Lunghi1

1Innovhub-SSI, Divisione Stazione Sperimentale per i Combustibili, viale A. De Gasperi, 3 - 20097 San Donato Milanese (MI), Italy.





Abstract

Current legislation about goods carriage (ADR - Agreement Concerning the International Carriage of Dangerous Goods by Road) sets the determination of several parameters related to the conditions of the used containers. Several of these parameters are required for the substance classification and the definition of the precautions to be adopted during transportation. One of the main potential hazards during freight is related to the thermal decomposition of the substance. Testing for the identification of decomposition in the carriage conditions can be time consuming and expensive, therefore different solutions have been attempted to simulate thermal behaviour of chemical compounds during transportation. This work focuses on the analysis of such methods and, in particular, on the model free methods for the determination of the decomposition kinetic of the studied compounds. This model is able to fit the kinetic behaviour of complex decomposition mechanisms more than others. The kinetic developed can be subsequently used to develop predictive models for the evaluation of transportation parameters, as for example the Self Accelerating Decomposition Temperature SADT, but also to track the product quality during time aging. Input data for this analysis are Differential Scanning Calorimetric (DSC) tests. They are safe, quick and cheap and can give important information about thermal behaviour of the studied substances. The model free methodology and the SADT determination has been performed for the decomposition of two different organic peroxides and a solid compound.

View Study: http://www.aidic.it/cet/12/26/098.pdf

 


 

Compatibility and simulation of the heating up of the propellant charge body of a high precision machine gun

Manfred A. Bohn1, Axel Pfersmann2

1Fraunhofer ICT, D-76318 Pfinztal, Germany
2Diehl BGT Defence GmbH & Co. KG, D-90552 Roethenbach a. d. Pegnitz, Germany





Abstract

The new precision machine gun in development at company Diehl uses a propellant charge without any case. It is based on consolidated NC double base ball powder. For ballistic reasons a defined distance between propellant charge body (PB) and the wall of the combustion chamber must be adjusted and for this a new feature was developed in cooperation with Fraunhofer ICT. The distance is achieved with foam stripes based on polyurethane energized by HMX. To avoid a degradation of the ballistic properties during use time, compatibility investigations using heat flow microcalorimetry have been performed to select suitable foam formulations. For this special assessment the criteria have been developed. A further design feature is a thermal insulation between the combustion chamber wall and the PB. This is also achieved by the energetic PUR foam. To design and predict this thermal insulation, FE calculations have been made using the thermal property and decomposition characteristics of the energetic foam and the PB, which have been parameterized by iso-conversional analysis. The calculations have been compared with real measurements of the times to autoignition at different burning chamber temperatures.

View study (pdf, 1021 KB)

View presentation (pdf, 798 KB)

 


 

Consideration of Autocatalytic Behavior in Determination of Self Accelerating Decomposition Temperature

Chuck Kozlowski1, Ken Kurko1

1Fauske & Associates, LLC, 16W070 83rd Street, Burr Ridge, Illinois 60527, USA


Abstract

When determining Self Accelerating Decomposition Temperatures (SADT) for shipment purposes, the kinetics of the decomposition reaction of the materials must be known. The simplified models assuming the first order decomposition kinetics are generally applied, however this traditional approach fails in correct SADT determination for autocatalytic and multistage overlapped reactions. For these cases a more universal, yet easily implemented, advanced method will be presented in which the detailed kinetic mechanism does not need to be known to correctly predict SADT. Using a series of DSC tests, AKTS-Thermokinetics software can extract kinetic parameters by the differential isoconversional approach. These kinetic parameters can then be applied for the prediction of the chemicals behavior in the kilogram scale. The results of the determination of the decomposition kinetics of azodicarbonamide is presented and applied to evaluate SADT for a 50 kg package. Results obtained by presented method will be compared to those determined by other methods.

View study (pdf, 182 KB)

View presentation (pdf, 2.28 MB)

 


 

Determination of SADT and Cook-Off Ignition Temperature by Advanced Kinetic Elaboration of DSC Data

B. Roduit1, P. Folly2, A. Sarbach2, B. Berger2, J. Mathieu2, M. Ramin3, B. Vogelsanger3, R. Kwasny4

1AKTS AG Advanced Kinetics and Technology Solutions, http://www.akts.com, TECHNOArk 3, 3960 Siders, Switzerland
2armasuisse, Science and Technology, http://www.armasuisse.ch, 3602 Thun, Switzerland
3Nitrochemie Wimmis AG, http://www.nitrochemie.com, 3752 Wimmis, Switzerland
4Chilworth Technology, Inc., http://www.chilworth.com, 08532 New Jersey, USA


Abstract

The exothermic decomposition parameters of a single-base propellant were obtained using differential scanning calorimeter (DSC) tests conducted at various heating rates. The DSC signals were processed using the Friedman isoconversional method to compute activation energy as a function of conversion. There was excellent agreement between the experimental and the simulation plots, which confirms the validity of the kinetic model used to describe the propellant’s exothermic decomposition. The kinetic parameters and heat balance were subsequently analyzed and used for a simulation of cookoff experiments conducted at different experimental rates (heating rates 3.3 - 1.0 K/h and a heat-wait-search mode). This study presents a simulation of the propellant’s adiabatic behaviour Time to Maximum Rate (TMR) under adiabatic conditions (TMRad) and self-accelerating decomposition temperature (SADT). This study also illustrates and discusses the effect of a material’s thermal conductivity on the time to ignition at various heating modes.

View Study (pdf, 638 KB)

 


 

Advanced Kinetics-based Simulation of Time to Maximum Rate under Adiabatic Conditions

B. Roduit1, W. Dermaut2, A. Lunghi3, P. Folly4, B. Berger4, A. Sarbach4

1 AKTS AG Advanced Kinetics and Technology Solutions, http://www.akts.com, TECHNOArk 3, 3960 Siders, Switzerland
2 Janssen Pharmaceutica NV, http://www.jnj.com, 2340 Beerse, Belgium
3 Stazione Sperimentale per i Combustibili, http://www.ssc.it/, 20097 San Donato Milanese, Italy
4 armasuisse, Science and Technology, http://www.armasuisse.ch, 3602 Thun, Switzerland


Abstract

Kinetic parameters of the decomposition of hazardous chemicals can be applied for the estimation of their thermal behavior under any temperature profile. Presented paper describes the application of the advanced kinetic approach for the determination of the thermal behavior also under adiabatic conditions occurring e.g. in batch reactors in case of cooling failure. The kinetics of the decomposition of different samples (different manufacturers and batches) of 3-methyl-4-nitrophenol were investigated by conventional DSC in non-isothermal (few heating rates varying from 0.25 to 8.0 K/min) and isothermal (range of 200-260°C) modes. The kinetic parameters obtained with AKTS-Thermokinetics Software were applied for calculating reaction rate and progress under different heating rates and temperatures and verified by comparing simulated and experimental signals. After application of the heat balance to compare the amount of heat generated during reaction and its removal from the system, the knowledge of reaction rate at any temperature profiles allowed the determination of the temperature increase due to the self-heating in adiabatic and pseudo-adiabatic conditions.
Applied advanced kinetic approach allowed simulation the course of the Heat-Wait-Search (HWS) mode of operation of adiabatic calorimeters. The thermal safety diagram depicting dependence of Time to Maximum Rate (TMR) on the initial temperature was calculated and compared with the results of HWS experiments carried out in the system with Φ-factor amounting to 3.2. The influence of the Φ-factor and reaction progress reached at the end of the HWS monitoring on the TMR is discussed. Presented calculations clearly indicate that even very minor reaction progress reduces the TMRad of 24 hrs characteristic for a sample with initial reaction progress amounting to zero.
Described estimation method can be verified by just one HWS-ARC, or by one correctly chosen ISO-ARC run of reasonable duration by knowing in advance the dependence of the TMR on the initial temperature for any Φ-factor. Proposed procedure results in significant shortening of the measuring time compared to a safety hazard approach based on series of ARC experiments carried out at the beginning of a process safety evaluation..

View Study: Journal of Thermal Analysis and Calorimetry, Vol. 93 (2008) 1, 163–173
http://dx.doi.org/10.1007/s10973-007-8866-1

 


 

Evaluating SADT by Advanced Kinetics-based Simulation Approach

B. Roduit1, P. Folly2, B. Berger2, J. Mathieu2, A. Sarbach2, H. Andres3, M. Ramin3, B. Vogelsanger3

1 AKTS AG Advanced Kinetics and Technology Solutions, http://www.akts.com, TECHNOArk 3, 3960 Siders, Switzerland
2 armasuisse, Science and Technology Centre, http://www.armasuisse.ch, 3602 Thun, Switzerland
3 Nitrochemie Wimmis AG, http://www.nitrochemie.com, 3752 Wimmis, Switzerland


Abstract

Present study depicts the extension of the method of the application of the advanced kinetic description of the energetic materials decomposition by its combination with the exact heat balance carried out by numerical analysis and the determination of the Self-Accelerating Decomposition Temperature (SADT). Moreover, the additional parameters such as thermal conductivity of the self-reactive substances, the type of containers and insulation layers, and different temperature profiles of the surrounding environment were taken into consideration. The results of DSC experiments carried out with different heating rates in the range of 0.25-4°C/min were elaborated by the Thermokinetics software. The application the Thermal Safety software and the kinetics-based approach led to proper selection of experimental conditions for SADT testing. The applied approach enabled the simulation of such scenario as the thermal ignition of self-reactive chemicals conditioned previously for 12h at 80°C and exposed later isothermally for 8h to temperatures between 120-180°C. Described method can be used for analysis of possible development of runaway during storage or transport of dangerous goods (TDG) and containers, and subsequent choice of the conditions that can prevent an accident.

View Study: Journal of Thermal Analysis and Calorimetry, Vol. 93 (2008) 1, 153–161
http://dx.doi.org/10.1007/s10973-007-8865-2

 


 

The Simulation of the Thermal Behavior of Energetic Materials based on DSC and HFC Signals

B. Roduit1, L. Xia1, P. Folly2, B. Berger2, J. Mathieu2, A. Sarbach2, H. Andres3, M. Ramin3, B. Vogelsanger3, D. Spitzer4, H. Moulard4 and D. Dilhan5

1 AKTS AG Advanced Kinetics and Technology Solutions, http://www.akts.com, TECHNOArk 3, 3960 Siders, Switzerland
2 armasuisse, Science and Technology Centre, http://www.armasuisse.ch, 3602 Thun, Switzerland
3 Nitrochemie Wimmis AG, http://www.nitrochemie.com, 3752 Wimmis, Switzerland
4 ISL, Institut franco-allemand de recherches de Saint-Louis, http://www.isl.eu, 68301 Saint Louis, France
5 CNES Centre National d’Etudes Spatiales, http://www.cnes.fr, 31401 Toulouse, France


Abstract

Two small calibre- and four medium calibre types of propellants were investigated non-isothermally (0.25-4 K/min) by Differential Scanning Calorimetry (DSC) in the range of RT-260°C and isothermally (60-100°C) by Heat Flow Calorimetry (HFC). The data obtained from both techniques were used for the calculation and comparison of the kinetic parameters of the decomposition process. The application of HFC allowed to determine the kinetic parameters of the very early stage of the reaction (reaction progress a below 0.02) what, in turn, made possible the precise prediction of the reaction progress under temperature mode corresponding to real atmospheric changes according to STANAG 2895. In addition, the kinetic parameters obtained from DSC data enabled determination of Self Accelerating Decomposition Temperature (SADT) and comparison of the predicted ignition temperature during slow cook-off with the experimental results. The study contains also the results of the calculation of the Time to Maximum Rate (TMRad) of the propellants under adiabatic conditions.

View Study: Journal of Thermal Analysis and Calorimetry, Vol. 93 (2008) 1, 143–152
http://dx.doi.org/10.1007/s10973-007-8864-3

 


 

Up-Scaling of DSC Data of High Energetic Materials

B. Roduit1, Ch. Borgeat1, B. Berger2, P. Folly2, H. Andres3, U. Schdeli3 and B. Vogelsanger3

1 Advanced Kinetics and Technology Solutions AKTS AG http://www.akts.com, TECHNO-Pôle, 3960 Siders, Switzerland
2 armasuisse, Science and Technology Centre, http://www.armasuisse.ch, 3602 Thun, Switzerland
3 Nitrochemie Wimmis AG, http://www.nitrochemie.com, 3752 Wimmis, Switzerland

Abstract

Differential scanning calorimetry (DSC) carried out with few heating rates was applied in the studies of the thermal properties of four energetic materials: EI® propellant, high explosive PBXW-17, pyrotechnic mixtures with composition B/KNO3 (50:50) and B/KNO3 (30:70). DSC signals, after optimization of the baseline, were used for the calculation of the kinetic parameters (KP) of the decomposition process applying advanced kinetic software designed by AKTS. The determination of the kinetic parameters was based on the differential iso-conversional method of Friedman. The correctness of the estimation of KP was checked by the comparison of the experimental and predicted courses of the decomposition. The slow cook-off experiments of above mentioned energetic materials were carried out with a heating rate of 3.3C h1. For the simulation of the experimental results, the heat balance based on the finite element analysis (FEA) was applied together with the advanced kinetic description of the reaction. The comparison of the experimental and simulated data indicates that applied procedure resulted in a very good prediction of the temperature of the ignition. Application of commonly used, simplified assumptions concerning the mechanism of the decomposition (such as 1 st or n th order mechanisms) led to significantly worse prediction of the cook-off temperatures.

View Study: Journal of Thermal Analysis and Calorimetry, Vol. 85 (2006) 1, 195202
http://dx.doi.org/10.1007/s10973-005-7388-y

 


 

The Prediction of Thermal Stability of Self-Reactive Chemicals

B. Roduit1, Ch. Borgeat1, B. Berger2, P. Folly2, B. Alonso3 and J. N. Aebischer3

1Advanced Kinetics and Technology Solutions AKTS AG http://www.akts.com, TECHNO-Pôle, 3960 Siders, Switzerland
2armasuisse, Science and Technology Centre, http://www.armasuisse.ch, 3602 Thun, Switzerland
3University of Applied Sciences of Western Switzerland, http://www.eif.ch, 1705 Fribourg, Switzerland

Abstract

An advanced study on the thermal behaviour of double base (boost and sustain propellant) rocket motor used in a ground to air missile has been carried out by differential scanning calorimetry (DSC). The presence of two propellants as well as the different experimental conditions (open vs. closed crucibles) influence the relative thermal stability of the energetic materials. Several methods have been presented for predictions of the reaction progress of exothermic reactions under adiabatic conditions. However, because decomposition reactions usually have a multi-step nature, the accurate determination of the kinetic characteristics strongly influences the ability to correctly describe the progress of the reaction. For self-heating reactions, incorrect kinetic description of the process is usually the main source of serious errors for the determination of the time to maximum rate under adiabatic conditions (TMRad). It is hazardous to develop safety predictive models that are based on simplified kinetics determined by thermoanalytical methods. Applications of finite element analysis (FEA) and accurate kinetic description allow determination of the effect of scale, geometry, heat transfer, thermal conductivity and ambient temperature on the heat accumulation conditions. Due to limited thermal conductivity, a progressive temperature increase in the sample can easily take place resulting in a thermal explosion. Use of both, kinetics and FEA [1], enables the determination of the reaction progress and temperature profiles in storage containers. The reaction progress and temperature can be determined quantitatively at every point in time and in space. This information is essential for the design of containers of self-reactive chemicals, cooling systems and the measures to be taken in the event of a cooling failure.

View Study: Journal of Thermal Analysis and Calorimetry, Vol. 80 (2005) 91–102
http://dx.doi.org/10.1007/s10973-005-0619-4