Scale-up Example for Storage

Liquids and solids are frequently handled in bulk at ambient temperatures. The heat generated by thermally unstable materials is generally quite low under such conditions. However, because of the large masses involved, even 

A comparison has been made between small scale test results and a field trial at a 17-ton scale for a solid compound [217]. The test results from a very sensitive calorimeter (Thermal Activity Monitor from ThermoMetric, Sweden) were substituted in a model, and the self-heating situation in bulk containers was predicted. The large-scale trial was carried out in a steel rectangular container lined with polyethylene. A control device was used to keep the container at a temperature of 40 to 45°C. Several thermocouples enabled monitoring of the temperature as a function of time in different places in the large container. 

The following conclusions were drawn. Microcalorimetry can be used to evaluate the heat generation characteristics of a solid material directly at the temperature of practical interest. However, in order to determine the worst case, the variability between batches of the substance must be determined which requires a considerable number of tests (over 100 trials in this specific case). Having obtained the heat generation as a function of temperature for with worst case, the safe storage diameter of storage vessels can be calculated and the equipment appropriately designed. 

The results of a number of tests such as those described in Chapter 2 led to classifications for the peroxide group. These tests included the determination of the hazards of decomposition (deflagration and detonation), bum rate, fire hazard, and reactivity hazards. Five different classes were formulated, as listed in the NFPA 43B Hazard Class, from the test results. Emergency procedures have been established for these five classes. 

Contamination of peroxides has been a major source of accidents by runaway decompositions, particularly during handling and use. Therefore all equipment that is in contact with peroxides must be thoroughly cleaned. When a diluent is used, it should be properly selected and its purity must be strictly controlled. The use of dedicated loading/unloading equipment and avoidance of the use of shared or manifold equipment are methods to reduce the possibility of cross-contamination. 

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