Adiabtic Reaction Calorimeter

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Analyzing & TestingBusiness Unit

Adiabatic Reaction CalorimetryMethod, Technique, Applications


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Measurement Results

A thermal runaway reaction is usu-ally investigated with the patentedHeat-Wait-Search mode (HWS).The temperature of reaction as wellas the temperature and pressure in-crease are measured. Additionally,the temperature and pressure in-crease rates can be determined.These are important values in orderto characterize the worst case sce-

nario of a substance.

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Thermal runaway reaction of a 20% solution of di-tert. butyl peroxide(DTBP) in toluene.


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Accelerating Rate Calorimeter 244

The cost-effective Accelerating RateCalorimeter 244 is designed to safelymeasure the amount and rate ofheat release associated with theprocessing or storage of chemicalswith a sample volume of 0.5 ml to7 ml. The key features are high per-formance, safety, usability, and flexi-bility with data integrity and robust-ness in a temperature range fromambient to 500C.

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Model 244


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Features Advantages Benefits

Over-Temperature Protection Two redundant safety thermocou-ples monitor calorimeter temper-atures and shut down the systemindependent of the software

Protects heaters and otherinstrument parts from runaways

Tube Heater Heats the pressure transfer tube tothe same temperature as the sam-ple

Prevents refluxing and sampleloss which can cause greatunderestimation of heats of reac-tion and temperature and pres-sure rates

Iso-Fixed Mode Allows the user to run isothermalaging tests for many days with mi-nimized drift

More accurate and reliable data

Automated Anneal,Temp. Calibration & Drift Tests

The user can quickly set-up theanneal-calibration-drift test se-quence. The software will auto-matically go from one test to thenext

No operator interventionnecessary, improved efficiency

Operating Modes

Heat-Wait-Search test for thermal runaway reactions Iso-Fixed / Iso-Track for studying storage/conditions/auto-catalytic

reactions (iso-aging technique) Ramp mode for fast screening of unknown samples

Optionally with VariPhi:

Scanning and isothermal modes allow detection of exothermic and

endothermic effects; similar to DSC method

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Model 244 Calorimeter Assembly


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Accelerating Rate Calorimeter 254

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The advanced Accelerating Rate Calorimeter 254 helps engineers and scien-tists to identify potential hazards and tackle key elements of process optimi-zation and thermal stability. As a highly versatile, miniature chemical reactor,it allows tests even at subambient temperature.

Features* Advantages Benefits

Motorized Headlift Operator not required to liftcalorimeter lid and can setworking height based onpersonal preference

Easy for all operators to use safelyand quickly

Temperature TrackingRate up to 200 K/min

Fast reactions can be trackedwithout the need to increase ther-mal inertia

More reliable data and widerapplication range

Machined Gas-TightCeramic Insulation

Provides consistent insulationproperties (i.e. density, geometry)

Constant insulation propertiesprovide for accurate test results,easy cleaning

Electrical ConnectionManagement

Separation of electrical connec-tions and measuring part

Easier maintenance

Operating Modes

Heat-Wait-Search test for thermal runaway reactions Iso-Fixed / Iso-Track for studying storage/conditions/auto-catalyticreactions (iso-aging technique)

Ramp mode for screening unknown samples


Scanning and isothermal modes allow detection of exothermic andendothermic effects; similar to DSC method

7* in addition to Model 244 features


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Automatic Pressure Tracking Adiabatic Calorimeter 264

APTAC 264 is a pressure balancing system for studying reactions withsample volumes of 5 ml to 75 ml. The pressure tracking rates amount tomax. 680 bar/min. As an adiabatic calorimeter, APTAC 264 can detect andtrack exotherms at heat generation rates ranging from 0.04 K/min to

400 K/min.

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APTAC 264


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Features* Advantages Benefits

Automated needle valve usedfor pressure balancing control

Capability to change the pressurein small increments

- Improves calorimetricperformance

- Reduces noise- Allows the usage of very thin-

walled or fragile sample vessels

Temperature Tracking Rate max.400 K/min

- Faster reactions can be trackedwithout the need to increasethermal inertia

- Increased sample size

- More reliable data and widerapplication range

- Better low-end thermal inertiaand more accurate onsettemperatures

Highest sensitivity

(0.002 K/min)

Detection of smallest

caloric effects even at lowestonset temperature

Extended range of applications

Injection, venting and stirring Completely integrated into thehardware and software

No additional costs orspace required

Operating Modes

Heat-Wait-Search test for thermal runaway reactionsIso-Fixed / Iso-Track for studying storage/conditions/auto-catalyticreactions (iso-aging technique)Ramp mode for screening unknown samples


Scanning and isothermal modes allow detection of exothermic andendothermic effects; similar to DSC method

Fire-exposure mode for simulation of thermodynamic andkinetic parameters of the reaction in a single test

Numerous automated features Easy to maintain andcalibrate

- Low operation cost- Higher sample throughput

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Lithium-ion battery

* in addition to Model 244 / 254 features


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The basis of the VariPhi is an additional controlled variable DC heater. With this option it is possible to define thethermal inertia in order to allow real-world thermal environment by compensating for heat lost from the sample to

the vessel. By operating different modes such as isothermal or scanning, endothermic and exothermic transitionscan be quantified, pressure data can be measured and the heat capacity of the sample can be determined.

VariPhi

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Theory

Sample holders absorb some of theenergy from the reaction. Howmuch heat is absorbed dependsupon the mass and heat capacity ofthe sample container. The ratio be-tween the product of the sample

mass and heat capacity to the prod-uct of the container mass and heatcapacity is what is known as ther-mal inertia.

When the sample mass is largecompared to the container mass,the thermal inertia approaches one.These tests are often called lowphi tests. They are important be-

mc x Cp,cms x Cp,s

mc is the mass of the containerCp,c is the heat capacity

of the containerms is the mass of the sampleCp,s is the heat capacity of the

sample

cause most industrial scale pro-cessing or storage conditions arelow thermal inertia conditions. Themass of a large storage container isvery small compared to the mass ofthe stored material. Since this is not

always true it is important to be ableto run multiple tests at varying ther-mal inertia. The VariPhi gets itsname because the user can quicklyand easily run low and high thermalinertia (Phi) tests in the same calo-rimeter using a small and inherentlysafer sample size.

=1+

Formula for thermal inertia

(-factor):


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Testing Vessels for the Accelerating Rate Calorimeters

A broad variety of testing vessels are available to meet different test requirements. Tube-type vessels are available forrunning smaller APTAC samples or energetic materials and for use with solids and pastes in the VariPhi. For bat-

tery testing, specific holders are designed for common commercial sizes. Custom vessels can also be designed.

MaterialsSpherical vessels with a wallthickness between 0.4 mm and5.1 mm are made of glass,Hastelloy, Inconel, stainless steel,

tantalum and titanium

Tube-type vessels with a wallthickness of 0.4 mm and0.7 mm are made of stainless

steel and titanium

Volume1 ml to 130 ml forspherical vessels0.1 ml to 9 ml fortube-type vessels

PressureUp to 1000 bar forspherical vesselsUp to 200 bar for

tube-type vessels

Standard Modes such as Heat-Wait-Search, Iso-Fixed orIso-Track

Compensation for heat lost to the sample container during test

Thermal inertia or Phi () factor can be definedSample heat capacity can be measured as a function of timeEndothermic transition can be analyzed

Scanning Mode

Reduces test time by 75% or more without loss of sensitivitySample heat capacity can be measured as a function of temperature

Endothermic transition can be analyzed

Fire-Exposure Mode

Simulation of additional heat to the sample

Thermocouples

SampleHeater

GuardHeater

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Diagram of the VariPhi


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Most important features of the three adiabatic calorimeters

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Software Solutions

The Accelerating Rate Calorimeters and APTAC run under a 32-bit Windows software package which includeseverything needed to carry out a measurement. The combination of easy-to-understand menus and automated

routines makes this software very user friendly.

Technical Features

Calorimeter Type 244 254

Temperature range

Pressure range(Standard)

Lift mechanism

Sample volume

Max. tracking rate

264

RT to 500C


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Measurement TaskThe measurement software for theAccelerating Rate Calorimeters andthe APTAC offers easy setup of ameasurement, selection of themeasurement mode and follow-upof the test progress. All raw datasignals are accessible on the screen,switches can be set with one mouseclick and simple plots of the runningmeasurements can be generated.The software stores data in binaryand ASCII formats, making it easy toload results into other softwarepackages for advanced analysis.

Advanced Thermokinetic andThermal SimulationMost decomposition reactions can-not be explained by simple kinetic

approaches. In most cases the na-ture of a reaction is based on var-ious steps (consecutive, parallel orcompetitive reactions). Multiple-stepreactions (up to 6 different steps)with more than 15 different reactiontypes can be used in NETZSCHThermokinetics for the analysis ofthe results. This is the ideal tool forunderstanding the real chemistryand kinetics behind a reaction.

Evaluation SoftwareAnalysis of the measurements isdone using the well-known Proteus

Thermal Analysis software. Presenta-tion of measurement results such asvarious temperatures, heat genera-tion rates or the pressure develop-ment can be done in one plot. Eval-

uation of characteristic tempera-tures (onsets, peaks, end tempera-tures) can be done on each signalcurve. Direct evaluation of decom-position enthalpies and standardkinetic analysis is possible.

Software Solutions

Screenshot of the measurement software

Screenshot of the Proteus evaluation software

Comparison of measured and calculated data for different phi-factors

Calculation of heat distributionfor chemical reactors


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Typical Applications

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Accelerating Rate Calorimeters by NETZSCH can be used for the thermal analysis of solid or liquid chemicals or forgas/liquid, liquid/liquid, gas/solid, and liquid/solid mixtures. They can also be used for process simulation of batchand semi-batch reactions, fire exposures, emergency relief venting, and physical properties measurement.

Autocatalytic Behavior

3-methyl 4-nitrophenol displays au-tocatalytic behavior when heated todecomposition temperatures. Thismay be studied using the Iso-Trackor Iso-Fixed feature of the calo-rimeter control software. Using theVariPhi option allows measure-ment of the sample under true iso-thermal conditions. The plot showsthe autocatalytic nature of the ma-terial where the sample heat flux ini-tially increases and then decreasesdue to consumption of reactant.The total heat release during the de-composition is simply obtained byintegration of the heat flux signal.

Energetic Materials

Ammonium nitrate is a base mate-rial for various applications, such asfertilizers. Measured here are solid-state phase transitions and melting(at 166C) as well as the decompo-sition behavior, starting at 221C.Such tests are crucial for safetystudies on such highly energeticmaterials.

Autocatalytic behavior of 3g 3-methyl 4-nitrophenol at 180C (isothermal)

Analysis of the phase changes and decomposition behavior of ammonium

nitrate using the VariPhi-option


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Vented Tests

The instrument may be operated invented or open vessel mode. Forvented tests a computer-controlledvalve is opened which allows ma-terial to flow to a 500 ml drop-outpot. If the pressure in the reactionvessel ceases to rise and the sam-ple temperature remains flat or istempered, then the reaction maybe classified as a vapor system. Thepressure in the reaction vessel maycontinue to rise, but at a reducedrate because of the increase in thehead space of the reaction vessel. Atthe end of the test, the contents ofthe drop-out pot are available for

analysis.

Battery Testing

Adiabatic reaction calorimeters al-low the researcher the ability to testfull cells in an adiabatic environmentto determine how well they performin real and exaggerated conditions.Cells can be charged and dis-charged while inside the calorimeterso many use scenarios can be test-ed. With the VariPhi option, cellscan be held isothermally during thecharge and discharge process inorder to get important data on heatenergy management.

3 vented tests showing increasing tempering as the vent set pressure

is reduced

Effect of state-of-charge on the thermal stability


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NETZSCH-Gertebau GmbHWittelsbacherstrae 4295100 Selb, GermanyPhone: +49 9287 881-0Fax: +49 9287 881-505E-mail: [email protected]

www.netzsch.comNGB

ARC/APTACE20000709MMM

Adiabtic Reaction Calorimeter

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