Simplified vent sizing equations for emergency relief requirements in reactors and storage vessels

Simplified vent sizing equations for emergency relief requirements in reaction kettles and storage vessels are obtained from analytical consideration. Venting modes include homogeneous‐vessel venting, all‐vacor venting, and all‐liquid venting; energy sources due to runaway chemical reactions and external heating are treated separately. The resulting equations have been shown via numerical examples to yield good agreement with detailed computer simulations, both in terms of temperature and pressure histories during venting and in vent size predictions. These equations are generally applicable over a wide range of overpressure situations and reduce to the correct limit at no overpressure. The relative merit of allowing for overpressure in various venting modes can be demonstrated using these equations. Because of their simple forms, requiring only pertinent physical property and thermal data, these equations readily lend themselves to quick but accurate vent sizing predictions.