Determination of SADT SADT and TMRad by Advanced Kinetic

1

Determination of Determination of SADTSADT and and TMRadTMRadby Advanced Kinetic Elaboration of DSC Databy Advanced Kinetic Elaboration of DSC Data

20082008Mary Kay OMary Kay O’’Connor Connor ProcessProcess SafetySafety CenterCenter

International SymposiumInternational SymposiumBeyondBeyond RegulatoryRegulatory ComplianceCompliance, , MakingMaking SafetySafety Second NatureSecond Nature

OctoberOctober 2828--29, 200829, 2008Hilton 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. KwasnyKwasny4411 AKTS AG, AKTS AG, TECHNOArkTECHNOArk 3, 3960 3, 3960 SidersSiders, Switzerland, Switzerland

22 armasuissearmasuisse, Science and Technology, 3602 , Science and Technology, 3602 ThunThun, Switzerland, Switzerland33 NitrochemieNitrochemie WimmisWimmis AG, 3752 AG, 3752 WimmisWimmis, Switzerland, Switzerland4 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(

RTE expA

dtd

E = constantSimplified 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 factoractivation energy

reaction progressreaction rate

reaction order

3

Determination of the kinetic Determination of the kinetic characteristicscharacteristics

4

Problem of interpretation Problem of interpretation of an observationof an observation

What do you see ?What do you see ?

5

Differential Differential isoconversionalisoconversional method of Friedmanmethod of Friedman

)( fRTE expA

dtd

Rate of the reaction is expressed by the Arrhenius equationRate of the reaction is expressed by the Arrhenius equation

TREConst

dtd 1ln

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

Differential Differential isoconversionalisoconversional method of Friedmanmethod of Friedman

22

TREConst

dtd 1ln

11

22

33

33

Baseline optimizationBaseline optimization

7

STANAG 2895 STANAG 2895 ––climatic categoriesclimatic categories

STANAG 2895STANAG 2895A2 (Hot dry)A2 (Hot dry)

Beijing Beijing

0

10

20

30

40

50

60

0 2 4 6 8 10time /year

tem

pera

ture

/°C

inventedinvented exampleexample

8

UpUp--scaling of DSC resultsscaling of DSC results

UpUp--scalingscaling

9


Example of adiabatic runaway scenarioExample of adiabatic runaway scenario

Before :Before :

10


Example of adiabatic runaway scenarioExample of adiabatic runaway scenario

After :After :

11

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

12

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 rateunder adiabatic conditions (TMRad)under adiabatic conditions (TMRad)

=0=0 Or Or ==

=1=1 ==TTadad

From DSCFrom DSC

adiabatic conditionsadiabatic conditions

> 1000 kg> 1000 kg

13

adiabaticadiabatic induction time (h)induction time (h)

criti

cal

criti

cal s

tarti

ngst

artin

gte

mpe

ratu

rete

mpe

ratu

re(( °°

C)

C)

Determination of TMRadDetermination of TMRad24h24h

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

=0=0Or Or ==

UWithWith

14time (h)time (h)

tem

pera

ture

tem

pera

ture

(( °°C

)C

)Determination of TMRadDetermination of TMRad24h24h

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

UNSAFE zoneUNSAFE zone

SAFE zoneSAFE zone

15

CookCook--offoff

Example of cookExample of cook--off experimentoff experiment

Before :Before :

After :After :

16

CookCook--offoff and SADTand SADT

??HeatHeat

BalanceBalance

DecompositionDecomposition KineticsKinetics

Thermal Thermal ConductivityConductivity

HeatHeatBalanceBalance

Thermal Thermal ConductivityConductivity

??DecompositionDecomposition

KineticsKinetics

DSCDSC

??HeatHeat productionproduction HeatHeat removalremoval

17

Heat Heat balancebalance under nonunder non-- adiabatic conditionsadiabatic conditions

wallwall

centercenter

reactioninput output accumulationheat

conductedin

heatgenerated

within

heatconducted

out

change in energystoredwithin

+ +=

-

Kinetics / DSCKinetics / DSC

18

CookCook--off experimentoff experiment

BeforeBefore

AfterAfter

Tsurrounding

(Experimental)

3.3 K/h3.3 K/h

?

19

Simulation of time to ignition for 0.1 < Simulation of time to ignition for 0.1 <

< 1 < 1 W(mW(m·· K)K)


BeforeBefore

AfterAfter

Tsurrounding

(Experimental)

3.3 K/h3.3 K/h32.2 h32.2 h 34.3 h34.3 h

20

Tsurrounding

(Experimental)


BeforeBeforeAfterAfter

1 K/h1 K/h

21


< 1 < 1 W(mW(m·· K)K)

Tsurrounding

(Experimental)


BeforeBeforeAfterAfter

1 K/h1 K/h

25.2 h25.2 h 33.4 h33.4 h

22

Tsurrounding

(Experimental)


BeforeBefore

AfterAfter

HeatHeat--WaitWait--SearchSearch

23


< 1 < 1 W(mW(m·· K)K)

Tsurrounding

(Experimental)


BeforeBefore

HeatHeat--WaitWait--SearchSearch49 h49 h 120 h120 h

AfterAfter

24

Wall T (calculated)

Center T (Calculated)te

mpe

ratu

re /°

CSimulation of ignition under Simulation of ignition under

HeatHeat--WaitWait--SearchSearch temperature mode applying temperature mode applying = 0.32 W/m/K = 0.32 W/m/K

Temperature mode: H-W-STime to ignition (exp): 110.4 hTime to ignition (exp): 110.4 hIgnition temp. (exp): 116.4Ignition temp. (exp): 116.4°°CCOptimal Optimal : 0.320 W/m/K: 0.320 W/m/K

time /h

Tsurrounding

(Experimental)

Ignition temperatureIgnition temperature

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The concept of SelfThe concept of Self--Accelerating Accelerating Decomposition Temperature (SADT)Decomposition Temperature (SADT)

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.

26

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

7 days or less7 days or less

overheat = 6overheat = 6°°CC

T T surroundingsurrounding --22°°CC

surrounding surrounding temperature temperature

SADT = 84SADT = 84°°CC

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0.1 1 10 100

75

80

85

90

95

100

105

110

OOO

OO

O

O

100 L50 L25 L10 L5 L1 L0.35 L

SA

DT

/°C

/W/(m·K)


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

= 0.32 W/m/K= 0.32 W/m/K

0.35L

25L50L

10L

Sample

volume change

1L

5L

100L

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0.1 1 10 100

75

80

85

90

95

100

105

110

OOO

OO

O

O

100 L50 L25 L10 L5 L1 L0.35 L

SA

DT

/°C

/W/(m·K)


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

= 0.32 W/m/K= 0.32 W/m/K

0.35L

25L50L

10L

Sample

volume change

1L

5L

100L

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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. BergerSwiss 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

Documents

Determination of SADT SADT and TMRad by Advanced Kinetic