DUG 48-860-1 Kurko - Consideration of Autocatalytic Behavior

8/13/2019 DUG 48-860-1 Kurko - Consideration of Autocatalytic Behavior

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Consideration of Autocatalytic BehaviorConsideration of Autocatalytic Behaviorin Determination of Self Acceleratingin Determination of Self Accelerating Decomposition TemperatureDecomposition TemperatureKenneth Kurko1, Charles Kozlowski1, Bertrand Roduit2

1Fauske & Associates, LLC, 16W070 83rd

Street, Burr Ridge, IL 60527, USA2AKTS AG Advanced Kinetics and Technology Solutions, TECHNOArk

1, 3960 Siders, Switzerland

Presented by Kenneth Kurko

to 2011 Fall DIERS User GroupOctober 12 2011


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What is a Self AcceleratingWhat is a Self Accelerating

Decomposition Temperature?Decomposition Temperature?United States SADT Test: SADT

is defined as the lowest

environmental temperature atwhich the center of the material

within the package heats to a

temperature 6C greater than

the environmental temperatureafter a lapse of a seven day

period or less. This period is

measured from the time whenthe temperature in the center of

the package reaches 2C below

the environmental temperature.

2Proprietary property of Fauske & Associates, LLC


3/23

What is Needed to Estimate a SADT?What is Needed to Estimate a SADT?

Package properties

- Size

- Heat

transfer

coefficient

Physical

properties

of self-reactive

substance

- Density

- Specific

heat

- Thermal conductivity

Decomposition kinetics



4/23

AzodicarbonamideAzodicarbonamide (CAS: 123(CAS: 123--7777--3)3)


Package properties

- Size (50 kg)

- Heat transfer coefficient (5 W/m2K)

Physical properties of self-reactive substance

- Density (1650 kg/m3)

- Specific heat (1050 J/kgK)- Thermal conductivity (0.1 W/mK)



5/23

AzodicarbonamideAzodicarbonamide (CAS: 123(CAS: 123--7777--3)3)

Package properties

- Size (50 kg)

- Heat transfer coefficient (5 W/m2K)

Physical properties of self-reactive substance

- Density (1650 kg/m3)

- Specific heat (1050 J/kgK)- Thermal conductivity (0.1 W/mK)




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Adiabatic Calorimetry

- ARC- VSP2

- ARSST

Heat Flow Calorimetry- TAM- C80

- DSC

Methods of Investigating Decomposition ReactionsMethods of Investigating Decomposition Reactions


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Methods of Investigating Decomposition ReactionsMethods of Investigating Decomposition Reactions

Adiabatic Calorimetry

- ARC- VSP2

- ARSST

Heat Flow Calorimetry- TAM- C80

- DSC


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NonNon--Isothermal DSC SignalsIsothermal DSC Signals

Temperature (C)

200180160140120

HeatFlow(W/g)

8

6

4

2

0

0.25C/min

0.5C/min

1C/min

2C/min


9/23


Isothermal DSC SignalsIsothermal DSC Signals

Time (h)

65.554.543.532.521.510.50

HeatFlow(W/g)

0.35

0.3

0.25

0.2

0.15

0.1

0.05

0

-0.05

-0.1

170C

165C


10/23


Basic Kinetic EquationBasic Kinetic Equation

Reaction rate is expressed by the equation

- Where A, E, f(), T, and t mean: pre-exponential factor in Arrheniusequation, activation energy, function of the reaction extent

which

form depends on the decomposition mechanism, temperature, andtime, respectively

Isoconversional methods (model free)

- Reaction model is not required

f

tTR

EexpA

dt

d


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Isoconversional MethodsIsoconversional Methods

Reactionrate

expressed

by

the

Arrhenius

equation

Reactionrateatagivenreactionprogress

isonlyafunctionofthetemperature

A()andE()arethepreexponentialfactorandapparentactivationenergy

Isoconversional methods (model free)

- Three main modifications of isoconversional method are applied in the

literature Differential (Friedman)

Integral (Flynn-Ozawa-Wall)

ASTM E698

T

1

R

E)(A'ln

dt

dln

=

fA


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Reaction Progress Under Isothermal (A)Reaction Progress Under Isothermal (A)

& Non& Non--Isothermal (B) ConditionsIsothermal (B) Conditions

Time (h)

4.543.532.521.510.50

Reactionprogress(-)

1

0.8

0.6

0.4

0.2

0

170C 165C

Temperature (C)

205200195190185180175170165160155150145

Reac

tionprogress(-)

1

0.8

0.6

0.4

0.2

0

0.25C/min 0.5C/min 1C/min 2C/min

rHQ

(A)

(B)


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Reaction Rate Under Isothermal (A)Reaction Rate Under Isothermal (A)

& Non& Non--Isothermal (B) ConditionsIsothermal (B) Conditions

Time (h)

4.543.532.521.510.50

Rea

ctionrate(-/s)

2.5E-4

2E-4

1.5E-4

1E-4

5E-5

0

170C

165C

Temperature (C)

205200195190185180175170165160155150145

Reactionrate(-/s)

0.007

0.006

0.005

0.004

0.003

0.002

0.001

0

0.25C/min

0.5C/min

1C/min

2C/min

rH

Q

dt

d

(A)

(B)


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Differential Isoconversional MethodDifferential Isoconversional Method

1000/T (1000/K)

2.352.32.252.22.152.12.05

ln(Reactionrate(-/s))(-)

-4

-6

-8

-10

-12

-14

0.01

0.02

0.050.1

0.7

0.8

0.9

0.95

0.98

0.99

The activation energy is determined from the slope of the lines,

connecting points plotted incoordinates: reaction rate vs. 1/T, obtained for the same reaction progress

at different

heating rates


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Dependence of EDependence of Eaa

& ln(A) on& ln(A) on

the Reaction Progressthe Reaction Progress

Reaction progress alpha (-)

10.80.60.40.20

E(k

J/mol)

200

180

160

140

120

100

80

Ln(A(alpha)f(alpha)(1/s))(-)

45

40

35

30

25

20

15


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Temperature (C)

225220215210205200195190185180175170165160155150145140

Rea

ctionRate(-/s)

0.015

0.01

0.005

0

ReactionProg

ress(-)

1

0.8

0.6

0.4

0.2

0

0.125C/min 0.25C/min 0.5C/min 1C/min 2C/min 4C/min

0.125C/min 0.25C/min

0.5C/min

1C/min

2C/min

4C/min


Simulation of the Reaction Progress (A) and ReactionSimulation of the Reaction Progress (A) and Reaction

Rate (B) Under NonRate (B) Under Non--Isothermal ConditionsIsothermal Conditions

(A)

(B)


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Simulation of the Reaction Progress (A) and ReactionSimulation of the Reaction Progress (A) and Reaction

Rate (B) Under Isothermal ConditionsRate (B) Under Isothermal Conditions

Time (h)

8.587.576.565.554.543.532.521.510.50

Rea

ctionRate(-/s)

3E-4

2E-4

1E-4

0

ReactionProg

ress(-)

1

0.8

0.6

0.4

0.2

0

175C

170C

165C

160C

175C 170C 165C 160C(A)

(B)


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TemperatureTemperature--Time Dependence forTime Dependence for

Different Sample MassesDifferent Sample Masses

with a fewwith a fewDSC or C80DSC or C80

experimentsexperiments

carried out oncarried out on

mgmg--scalescale

SADT

TMRad

Shelf-

life

mgmg

kgkg

tonton

To

=120C?

To

=120C?

Azodicarbonamide (CAS: 123-77-3)

To

=120C?


19/23


Heat Balance: Kilogram ScaleHeat Balance: Kilogram Scale

tC

H

r

T

r

g

r

T

rCt

T

p

r

p

1

Thermal

conductivity

?? Decompositionkinetics

Accumulation

reaction output accumulation

heat

conducted

in

heat

generated

within

heat

conducted

out

change in

energy

stored

within+ +=

Heat balance combined with numerical

analysis enables the determination ofthe

(i) heat accumulation and

(ii) reaction rate and progress

for any surrounding temperature profile

input


20/23


Prediction of SADT Applying HeatPrediction of SADT Applying Heat

Balance & Kinetic DataBalance & Kinetic Data

Time (day)1086420

Temperature(C)

122

120

118

116

114

112

110

SADT=114C,50kg,1650kgm -3,1.05Jg^-1K^-1,0.1Wm -1K^-1,-1373.5Jg^-1,5Wm -2K^-1

overheat 6C

T surrounding -2 C

7 day or less

time = 6.49 day

SADT = 114 C

The SADT is 114C. This temperature is the lowest environment temperature at which overheat in the middle ofthe specific packaging exceeds 6C (T6) after a lapse of the period of seven days (168 hours) or less. This period

is measured from the time when the packaging center temperature reaches 2C below the surrounding

temperature. This overheat of 6C occurs after about 6.5 days.

centersurface

outside


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Simulation of Thermal Explosion of a 50 kgSimulation of Thermal Explosion of a 50 kg

Package of Azodicarbonamide (TPackage of Azodicarbonamide (Tambamb

= 120= 120C)C)


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SADT ResultsSADT Results

SADT predicted: 114C

SADT literature: 115C

(M.W. Whitmore, J.K. Wilberforce, J. Loss Prev. Process Ind., 6 (1993) 95)

The simulated SADT values of azodicarbonamide being in very good

agreement with those already determined indicate the

(i) correct collection of the experimental DSC data,

(ii) accurate procedure of the determination of kinetic parameters, and

(iii) precise evaluation of the thermal safety behavior implemented inAKTS-Thermokinetics software.


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DUG 48-860-1 Kurko - Consideration of Autocatalytic Behavior

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