Worked example using Huffs method

In addition to data already supplied in 6.5 (and repeated here), the Boyle time has been measured as 3.75 seconds. The Table below gives data (see 6.5) at the maximum accumulated pressure of 2 6 bara 

This calculated relief area is very close to the 0.0378 m2 calculated using Leung s method in 6.5. 

Fauske s method14,51 (given below) is based on emptying the reactor (or achieving vapour/ liquid disengagement) before the pressure has risen from the relief pressure to the maximum accumulated pressure in a vented system. The method incorporates the simplified equilibrium rate model, ERM, for saturated liquid inlet (see 9.4.2) together with the Clausius-Clapeyron relationship (discussed in 6.3.3). The method makes use of adiabatic experimental rate data for the runaway, whose measurement is described in Annex 2. 

The version of Fauske s method given in A5.3.2 below is simplified by assuming that two-phase relief occurs until the reactor is empty (a safe assumption for vapour pressure systems). This makes the results directly comparable with those from Leung s method (in 6.3). The full version of Fauske s method14,51 allows account to be taken of vapour/ liquid disengagement before the vessel has emptied. This method is given in A5.3.4 below. 

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A worked example of the use of Huffs method is given below. 

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