(115d) Example of Design and Installation of Reactor Emergency Relief Device, Knock-out Tank and Vent Line System for a Vapor/Gas Hybrid System

In a pharmaceutical manufacturing process, a hydroxylamine/acetic acid premix was formed in a glass-lined reactor since the presence of metals will reduce the thermal stability of hydroxylamine. To design the reactor pressure relief system for the double charge of hydroxylamine with exposure to metal upset scenario, adiabatic calorimeter tests using VSP (Vent Sizing Package) for hydroxylamine/acetic acid mixture were performed. The sizing of the rupture disc for the vapor/gas hybrid system using testing data will be presented. The vent stream from the reactor is discharged into a horizontal knock-out tank (gravity separator) before releasing to atmosphere. The design of the knock-out tank and vent lines will be discussed, including methods to prevent moisture collection in the tank. The steady-state reaction forces for the rupture disc vent line during venting were evaluated. The knock-out tank services several reactors and other pressure vessels in the facility. The design of the relief vent piping and manifolds prior to the knock-out tank will be discussed. Valuable lessons learned and considerations exercised during engineering design and field installation will be presented.