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1 Determination of Determination of SADT SADT and and TMRad TMRad by Advanced Kinetic Elaboration of DSC Data by Advanced Kinetic Elaboration of DSC Data 2008 2008 Mary Kay O Mary Kay O Connor Connor Process Process Safety Safety Center Center International Symposium International Symposium Beyond Beyond Regulatory Regulatory Compliance Compliance , , Making Making Safety Safety Second Nature Second Nature October October 28 28 - - 29, 2008 29, 2008 Hilton Hilton Conference Conference Center Center College College Station, Texas, USA Station, Texas, USA B. B. Roduit Roduit 1 1 , P. , P. Folly Folly 2 2 , A. , A. Sarbach Sarbach 2 2 , B. , B. Berger Berger 2 2 , J. , J. Mathieu Mathieu 2 2 , M. , M. Ramin Ramin 3 3 , B. , B. Vogelsanger Vogelsanger 3 3 ,R. ,R. Kwasny Kwasny 4 4 1 1 AKTS AG, AKTS AG, TECHNOArk TECHNOArk 3, 3960 3, 3960 Siders Siders , Switzerland , Switzerland 2 2 armasuisse armasuisse , Science and Technology, 3602 , Science and Technology, 3602 Thun Thun , Switzerland , Switzerland 3 3 Nitrochemie Nitrochemie Wimmis Wimmis AG, 3752 AG, 3752 Wimmis Wimmis , Switzerland , Switzerland 4 4 Chilworth Technology, Inc., 08532 New Jersey, USA Chilworth Technology, Inc., 08532 New Jersey, USA

Determination of SADT SADT and TMRad by Advanced Kinetic

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Slide 1Determination of Determination of SADTSADT and and TMRadTMRad by Advanced Kinetic Elaboration of DSC Databy Advanced Kinetic Elaboration of DSC Data
20082008 Mary Kay OMary Kay O’’Connor Connor ProcessProcess SafetySafety CenterCenter
International SymposiumInternational Symposium BeyondBeyond RegulatoryRegulatory ComplianceCompliance, , MakingMaking SafetySafety Second NatureSecond Nature
OctoberOctober 2828--29, 200829, 2008 Hilton Hilton ConferenceConference CenterCenter
CollegeCollege Station, Texas, USAStation, Texas, USA
B. B. RoduitRoduit11, P. , P. FollyFolly22, A. , A. SarbachSarbach22, B. , B. BergerBerger22, J. , J. MathieuMathieu22, M. , M. RaminRamin33, B. , B. VogelsangerVogelsanger33,R. ,R. KwasnyKwasny44 11 AKTS AG, AKTS AG, TECHNOArkTECHNOArk 3, 3960 3, 3960 SidersSiders, Switzerland, Switzerland
22 armasuissearmasuisse, Science and Technology, 3602 , Science and Technology, 3602 ThunThun, Switzerland, Switzerland 33 NitrochemieNitrochemie WimmisWimmis AG, 3752 AG, 3752 WimmisWimmis, Switzerland, Switzerland 4 4 Chilworth Technology, Inc., 08532 New Jersey, USAChilworth Technology, Inc., 08532 New Jersey, USA
2
Determination of the kinetic Determination of the kinetic parameters: simplified reaction modelparameters: simplified reaction model
)1(
E = constant Simplified model f(a) = (1-a)n
Where n-reaction order is assumed to be 0, 1 or 2
n
Still commonly used simplification: ‘ Let‘s assume that the reaction is of n-th order ‘
pre-exponential factor activation energy
4
Problem of interpretation Problem of interpretation of an observationof an observation
What do you see ?What do you see ?
5
)( f RT E expA


Rate of the reaction is expressed by the Arrhenius equationRate of the reaction is expressed by the Arrhenius equation
TR EConst
IsoconversionalIsoconversional methodsmethods (model free):(model free):
There are 3 main modifications of There are 3 main modifications of isoconversionalisoconversional method:method:
-- Differential (Friedman)Differential (Friedman)
-- Integral (FlynnIntegral (Flynn--OzawaOzawa--Wall)Wall)
-- Advanced integral based on nonAdvanced integral based on non--linear procedure (linear procedure (VyazovkinVyazovkin))
Differential isoconversional method of FriedmanDifferential isoconversional method of Friedman
6
22
STANAG 2895STANAG 2895 A2 (Hot dry)A2 (Hot dry)
Beijing Beijing
te m
pe ra
tu re
UpUp--scalingscaling
9
Example of adiabatic runaway scenarioExample of adiabatic runaway scenario
Before :Before :
Example of adiabatic runaway scenarioExample of adiabatic runaway scenario
After :After :
ARC experiments ARC experiments underunder (pseudo(pseudo--) adiabatic conditions) adiabatic conditions
Temperature and pressure dependence on time recorded during ARC Temperature and pressure dependence on time recorded during ARC HWS HWS experiment at air pressure of 1.8 MPa experiment at air pressure of 1.8 MPa
Detection limit = 0.02 K/minDetection limit = 0.02 K/min
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Link between kinetics Link between kinetics and TMR under adiabatic conditionsand TMR under adiabatic conditions
Determination of time to maximum rateDetermination of time to maximum rate under adiabatic conditions (TMRad)under adiabatic conditions (TMRad)
=0=0 Or Or ==
cr iti
ca l
cr iti
Thermal safety diagram: Thermal safety diagram: Dependence of Dependence of TMRadTMRad on starting temperaturestarting temperature
T = 90T = 90°°CC TMRadTMRad = 24 hours= 24 hours
UNSAFE zoneUNSAFE zone
SAFE zoneSAFE zone
Adiabatic runaway scenario: Adiabatic runaway scenario: Time to Maximum Rate under adiabatic conditions Time to Maximum Rate under adiabatic conditions
TT00 = 90= 90°°CC TMRadTMRad = = ~~ 24 hours24 hours
TTadad = 1866= 1866°°CC
Before :Before :
After :After :
wallwall
centercenter
+ +=
-
19
Simulation of time to ignition for 0.1 < Simulation of time to ignition for 0.1 <
< 1 < 1 W(mW(m·· K)K)
20
Tsurrounding
(Experimental)
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Simulation of time to ignition for 0.1 < Simulation of time to ignition for 0.1 <
< 1 < 1 W(mW(m·· K)K)
22
Tsurrounding
(Experimental)
BeforeBefore
AfterAfter
HeatHeat--WaitWait--SearchSearch
23
Simulation of time to ignition for 0.1 < Simulation of time to ignition for 0.1 <
< 1 < 1 W(mW(m·· K)K)
AfterAfter
24
HeatHeat--WaitWait--SearchSearch temperature mode applying temperature mode applying = 0.32 W/m/K = 0.32 W/m/K
Temperature mode: H-W-S Time to ignition (exp): 110.4 hTime to ignition (exp): 110.4 h Ignition temp. (exp): 116.4Ignition temp. (exp): 116.4°°CC Optimal Optimal : 0.320 W/m/K: 0.320 W/m/K
time /h
UN-Regulations…T (°C)
t (h)
SADT SADT is defined asis defined as ““the lowest environment temperature at which overheat the lowest environment temperature at which overheat in the middle of the specific commercial packing in the middle of the specific commercial packing
exceeds 6exceeds 6°°C after a laps of period of seven days (168 hours) or lessC after a laps of period of seven days (168 hours) or less””.. This period is measured from the time when the packaging center This period is measured from the time when the packaging center temperature temperature
reaches 2reaches 2°°C below the surrounding temperature.C below the surrounding temperature.
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Determination of SelfDetermination of Self--Accelerating Accelerating Decomposition Temperature (SADT)Decomposition Temperature (SADT)
SADT is 84SADT is 84°°C. C. This temperature is the lowest environment temperature at which This temperature is the lowest environment temperature at which overheat in the middle of the overheat in the middle of the specific packaging exceeds 6 specific packaging exceeds 6 °°C (C (T6) after a lapse of the period of seven days (168 hours) or T6) after a lapse of the period of seven days (168 hours) or less. This period is measured from the time when the packaging cless. This period is measured from the time when the packaging centre temperature reaches entre temperature reaches
2 2 °°C below the surrounding temperature. This overheat of 6C below the surrounding temperature. This overheat of 6°°C occurs after about 5 days.C occurs after about 5 days.
wallwall
centercenter
overheat = 6overheat = 6°°CC
surrounding surrounding temperature temperature
SADT = 84SADT = 84°°CC
O
O
100 L 50 L 25 L 10 L 5 L 1 L 0.35 L
S A
D T
Determination of SelfDetermination of Self--Accelerating Accelerating Decomposition Temperature (SADT)Decomposition Temperature (SADT)
SADT as a function of the thermal conductivity SADT as a function of the thermal conductivity and sample volume expressed in L. and sample volume expressed in L. The circles represent the simulation of SADT when applying the The circles represent the simulation of SADT when applying the value taken from the value taken from the
HH--WW--SS--mode simulationmode simulation
O
O
100 L 50 L 25 L 10 L 5 L 1 L 0.35 L
S A
D T
Determination of SelfDetermination of Self--Accelerating Accelerating Decomposition Temperature (SADT)Decomposition Temperature (SADT)
SADT for various the sample volume expressed in L. SADT for various the sample volume expressed in L. The circles represent the simulation of SADT when applying the The circles represent the simulation of SADT when applying the value taken from the value taken from the
HH--WW--SS--mode simulationmode simulation
1L
5L
100L
29
ConclusionsConclusions
Independent of the mass of the sample investigated in any Independent of the mass of the sample investigated in any thermoanalyticalthermoanalytical experiment, the correct description of the experiment, the correct description of the
time to thermal ignition of a decomposition reaction requires time to thermal ignition of a decomposition reaction requires the knowledge of the knowledge of two important parameters two important parameters
(i) the kinetics of the investigated reaction and (i) the kinetics of the investigated reaction and (ii) the heat balance of the system.(ii) the heat balance of the system.
Depending on the mass of the sample both these Depending on the mass of the sample both these parameters differently contribute to the reaction progress.parameters differently contribute to the reaction progress.
‘‘Safety through calculations not by accidentsSafety through calculations not by accidents’’
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Advanced Kinetics and Technology Solutions
AKTS AG, C. Borgeat, C. Luyet, L.Xia, N. Solioz, JG. Pont AKTS AG, C. Borgeat, C. Luyet, L.Xia, N. Solioz, JG. Pont
armasuisse, Dr. P. Folly, Dr. A.Sarbach and B. Bergerarmasuisse, Dr. P. Folly, Dr. A.Sarbach and B. Berger Swiss Federal office of Public Health, Dr. V. DudlerSwiss Federal office of Public Health, Dr. V. Dudler
Univ. of Western Switzerland, Prof. J.N. Aebischer, Univ. of Western Switzerland, Prof. J.N. Aebischer, S. Gomez, B. AlonsoS. Gomez, B. Alonso
Swiss Institute of Safety and Security,Swiss Institute of Safety and Security, Dr. P. Reuse, Prof. F. Stoessel, Dr. H. Fierz Dr. P. Reuse, Prof. F. Stoessel, Dr. H. Fierz
Nitrochemie Wimmis AG, Dr. M. Ramin, Dr. U. SchNitrochemie Wimmis AG, Dr. M. Ramin, Dr. U. Schäädeli, deli, Dr. B. VogelsangerDr. B. Vogelsanger
Acknowledgements Acknowledgements Our partners and friendsOur partners and friends
ChilworthChilworth Technology, Inc., Technology, Inc., Dr. R. KwasnyDr. R. Kwasny
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