Calculating vents. DIERS methods — Hybrid systems

DIERS (Design institute for emergency relief systems) methods are used to protect reactors and enclosed vessels from runaway reactions. DIERS methods have already been the subject of two articles in Techniques de l'Ingénieur.

The article [SE 5 041] [1] provides an overview of DIERS' methods for sizing emergency vents to protect reactors and other equipment against runaway condensed-phase reactions.

DIERS methods distinguish three categories of reaction systems according to the type of pressurization they produce:

• High vapor systems are the subject of the same article [SE 5 041] . They account for 90% of vent sizing for reaction control.

• Gassy reactions are the second category of reaction systems for which we have specific methods of sizing emergency vents. These reaction systems are the subject of the article [SE 5 042][2] in Techniques de l'Ingénieur. They account for less than 10% of emergency vent sizing cases.

• Finally, hybrid systems are reaction systems that pressurize enclosures by steam pressure and incondensable gas production simultaneously. They are the subject of this article [SE 5 043] .

The demand for sizing this type of reaction system is relatively low, due to the complexity of the situation, the complexity of vent calculation methods and the difficulty of obtaining the experimental data required for the calculation. Hybrid reaction systems do exist, however, for which empirical...