THERMAL SAFETY Software (TS)

Evaluation of Safety Parameters TMRad, Safety Diagrams,
Simulation of ARC and Runaway Reactions, Determination of SADT

Technical comments

Kinetic analysis of solids of the quasi-autocatalytic decomposition type: SADT determination of low-temperature polymorph of AIBN

Simulations of SADT values based on the heat balance of the system are presented for azobisisobutyronitrile (AIBN). These simulations used kinetic parameters obtained from heat flow calorimetry experiments performed at temperatures in the stability range of low-temperature (L-T) polymorph of AIBN. Thermal Activity Monitor (TAM) data were collected in the range of 55-70 °C. The simulated SADT value for L-T AIBN amounts to 46 °C. This is very similar to the computed results obtained in the BAM project for the high-temperature (H-T) form of AIBN which amounts to 47 °C and is also in full agreement with the large scale experimentally found SADT of AIBN (47 °C) …

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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

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) …

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

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 72-94 °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 …

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Parameters Influencing the Correct Thermal Safety Evaluations of Autocatalytic Reactions

The stability of live-attenuated viruses is very challenging due to thermal sensitivity; therefore, solid form is usually required (often freeze-dried products). Micropellet technology is a lyophilization technology that has the potential to provide greater flexibility in the presentation of a given vaccine particularly in multi-dose format or in combination of different vaccines. As a novel vaccine alternative process, this spray freeze-dried (SFD) micropellet technology was evaluated using as a model a yellow fever virus produced in Vero cells (vYF) …

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

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 …

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

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 …

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Kinetic Evaluations for the Transportation of Dangerous Chemical Compounds

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 …

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Consideration of Autocatalytic Behavior in Determination of Self Accelerating Decomposition Temperature

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 …

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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

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 …

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

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) …

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

Two small calibre and four medium calibre types of propellants were investigated non-isothermally (0.25-4 K min-1) 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 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 …

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Evaluating SADT by Advanced Kinetics-based Simulation Approach

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 …

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

An adiabatic calorimeter is very often used for the investigation of runaway of exothermic reactions. However the ideal adiabatic environment is a theoretical state which during laboratory scale testing cannot be obtained but may only be approached. Deviation from the fully adiabatic state comes from (i) the thermal inertia of the test system or heat lost into the sample container and (ii) the loss of heat from the container itself to the environment that reflects the ‘operational adiabaticity’ of the instrument…

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Up-Scaling of DSC Data of High Energetic Materials

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 …

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The Prediction of Thermal Stability of Self-Reactive Chemicals

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 …

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