Scale-up of Vent Size Package VSP Results

The Vent Size Package (VSP) apparatus was described in Section 3.3.2.6. The relatively small 100-cm3 test cell size implies that the samples tested may not be fully representative of commercial scale systems in some cases. The contents of the test vessel may be stirred, although the stirring facilities are not 

A simplified VSP procedure which enables a quick estimate of the required vent diameter is discussed in [191]. The venting characteristics in connection with runaway chemical reactions can be related to vapor and gassy (including hybrid) systems. 

For a pure vapor system (AT/At driven), where the runaway reaction can be kept under control by the latent enthalpy of evaporation (tempered system), a relatively simple expression can be used for the estimation of the necessary vent diameter. 

For some gassy systems (Ap/At driven), viscosity considerations become important which make testing difficult if not prohibitive. 

For gassy and for tempered systems, the flow rate can also be measured in a simulated vent line (same 1/d ratio) of diameter do. Additional calculation formulas are given in [191]. 

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