Phi-TEC II | Adiabatic Calorimeter for Vent Sizing & Thermal Runaway Testing

The Phi-TEC II is a low thermal inertia (low phi-factor) adiabatic calorimeter with the capability of producing the conditions in large-scale chemical reactors. This key to this is the low operation at low phi-factor (see below) which is not possible in standard “ARC-type” adiabatic calorimeters but this capability opens up many new applications.

The system can run samples in the range 1 to 100ml in volume, with the small size being used for screening of hazards (similar to conventional “ARC” testing) and the larger volume for the low phi-factor type tests. All samples can be stirred with magnetic flea as the system is fitted with this feature but in addition, overhead mechanical agitation is also possible where higher viscosity or multiphase samples is a concern. Standard Pre-programmed Tests make runs quick and efficient and simple standard test cells keep consumable costs to a minimum.

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The Phi-Factor

When it comes to safety, getting the right answers is a must. A second point to consider on calorimeters is the Phi-Factor.

In an exothermic reaction, a proportion of the energy released is absorbed by the test cell in which the test is performed – this is expressed in terms of the Phi-Factor. In a test in which the phi-factor is high, means a large amount of heat is lost to the test cell and this effectively slows down the temperature rise rate and reduces the final temperature. In a test allowing low phi-factor conditions, virtually all the energy of the reaction is retained in the sample, which is closer to the conditions of large scale plant and hence represents data that is ideal for scale-up simulation.

Phi-TEC II can be run under both low and high phi-factor conditions, depending on the application.

Only a low-phi factor calorimeter such as the Phi-TEC II can deliver the accurate, scalable safety vital for transferring processes from the lab to pilot or plant scale. For example, this low thermal inertia will enable vent sizing under runway conditions including situations where two-phase venting is involved.



The system will allow tests that might otherwise be performed in TSu & Phi-TEC I -type devices. Key data produced includes

  • So-called “Onset” Temperatures for exotherms
  • Runaway data, such as rates of pressure and temperature rise
  • Enthalpy of reaction
  • Reaction kinetics


Applications of the data include:

  • Determination of Venting behaviour (Gassy, tempered, hybrid)
  • Determination of Flow Regime (Two-phase or single-phase)
  • Kinetic data (eg for TMR, or TNR calculations)
  • Safe transport and storage prediction


Process Safety Scale Up Brochure 0620.pdf

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