Phi-TEC I | Adiabatic Reaction Calorimeter For Hazard Screening

Rapid reactions

If there is a need to characterize especially rapid decompositions, the Phi-TEC I offers a high data-rate acquisition option, which provides higher resolution data on the rate of pressure

and temperature changes. When scaling up a process, accurate knowledge of an exothermic event is vital to ensure the magnitude of the thermal runaway risk is fully understood.

Adiabatic calorimetry

Large scale reactors lose very little of the heat generated in a reaction to the surroundings. This poses a potential hazard when operating at large scale, as that heat will be retained within the reactor. At best this will require plant cooling and at worst may trigger a thermal runaway.

The Phi-TEC I mimics the processes at large scale, while operating at laboratory volumes.

Characterizing the thermal runaway (4)

Secondary thermal runaway riskProviding a direct measurement of the sample temperature, coupled with a rapid response to thermal changes, the Phi-TEC I accurately tracks exothermic events and maintains adiabatic conditions.

Adiabatic screening of a process enables accurate characterization of the onset temperature (Td) and facilitates calculation of the time to maximum rate (TMRd), the adiabatic temperature rise (ΔTad,d) and the rate of pressure change. These key parameters can help describe the magnitude of the thermal runaway hazard.

 

 

 

 

 

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The system is completely computer-controlled and features a range of high-pressure test cells, magnetic stirring and pressure and temperature logging. Standard pre-programmed Tests make runs quick and efficient and simple standard test cells keep consumable costs to a minimum.

A time-consuming feature of traditional “ARC-type” calorimeters, which also leads to poor results, is the empirical method used to “calibrate” the system in order to produce adiabatic conditions. HEL uses a proprietary model developed exclusively for phi-tec that uses an on-line calibration technique based on a mathematical model and which keeps the system in constant calibration without the need for lengthy runs.

Samples are stirred as standard and both liquid and powder samples can be tested.

The system employs two standard test types

  • Rapid hazard Screening…

…For the early screening of liquids and powders, with a view to assessing their thermal stability and explosion potential in a matter of an hour or so. This involves ramping the sample temperature until an exotherm is induced – analogous to a DSC test, but with the added feature of pressure data, a larger and more reliable sample size and ability to stir the sample while heating.

  • Heat – Wait – Search…

This is the classical “ARC” test developed by Dow and widely used for decades. This provides more accurate data as the sample is heated stepwise with pauses in between heatings to “search” for an exotherm within the sensitivity of the device. Once an exotherm is detected, adiabatic tracking commences, without any external heating, essentially allowing the exotherm to drive the runaway.