PHI-TEC

The PHI-TEC II adiabatic calorimeter as shown in Figure 12-17 was developed by Hazard Evaluation Laboratory Ltd. (UK). The PHI-TEC can be used both as a high sensitivity adiabatic calorimeter and as multi-purpose vent sizing device [17,18]. The PHI-TEC employs the principles established by DIERS and includes advanced features compared to the VSP. It also provides important information for storage and handling and provides useful insight into the options suitable for downstream disposal of vented material. 

Figure 12-17. PHI-TEC adiabatic calorimeter. (Source Hazard Evaluation Laboratory Ltd.)...

The first derivative of Equation 12-22, denoted by the subseript s, eorresponds to the heating rate at the set pressure, and the seeond derivative, denoted by subseript m, eoiTesponds to the temperature rise at the maximum turnaround pressure. Both derivatives are determined from an experiment (e.g., in the PHI-TEC or VSP). 

The PHI-TEC or VSP bench scale apparatus can be employed to determine information about the self-heat rate and vapor disengagement when this is not readily available. Additionally, the VSP equipment can be used for flashing flow characteristics using a special bottom vented test cell. Here, the flowrate, Gq (kg/sm ), is measured... 

Singh, J., PHI-TEC Enhaneed Vent Sizing Calorimeter Appliea-tion and Comparison with Existing Deviees, Proeeeding of the Int. Symp. on Runaway Reaetions, AIChE/CCPS, pp. 313-330, Boston, MA, Mareh 7-9, 1989. 

The original Vent Size Package (VSP) became available first in the United States, and is currently distributed by Fauske and Associates. A very similar type of equipment, called PHI-TEC, is available in Europe. 

In this context, the term adiabatic refers to calorimetry conducted under conditions that minimize heat losses to the surrounding environment to better simulate conditions in the plant, where bulk quantities of stored or processed material tend to minimize cooling effects. This class of calorimetry includes the accelerating rate calorimeter (ARC), from Arthur D. Little, Inc., and PHI-TEC from Hazard Evaluation Laboratory Ltd. 

Singh, J. (1993) Reliable scale-up of thermal hazards data using the Phi-Tec II calorimeter. Thermochimica Acta, 226 (1-2), 211-20. 

VSP , the PHI-TEC II , the RSST and the Chilworth stainless-steel dewar, as well as the self-made types. On top of these there are several other measuring set-ups, which are more or less modified versions of those mentioned. The general discussion of adiabatic calorimetry shall be conducted on the basis of the general dewar technique as a comparative study of the commercially available devices is not the subject of this book. 

Another development is the Phi-Tec adiabatic calorimeter (Figure 3.14). It is broadly similar to the VSP but the cell contents can be vented outside the equipment rather than into the containment vessel. 

Singh, J 1989, PHI-TEC enhanced vent sizing calorimeter, Int Symp on Runaway Reactions. 313-330 (CCPS, AIChE. USA). 

Adiabatic reaction calorimeter sample volume 7-11 ml. Phi-TEC II Different cells from 10 to 120 ml temperature range up to 500 °C pressure range up to 138 bat... 

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