Development of small-scale experimental method for vent sizing and observation of runaway reaction

Abstract

Safety valves for reaction runaway are important to install in order to prevent ruptures of equipment. However, safety valves are not easy to accurately design for a pressure increase due to a runaway reaction. A vent-sizing method for two-phase flow was developed by the Design Institute for Emergency Relief Systems (DIERS) under the auspices of AIChE in 1987, and the API standard 520 and ISO 4126–10 was published in 2010s’. These standards defined conservative assumptions. Therefore, sometimes non-realistic results, such as bigger safety valves than the reactor diameter, are obtained. For the investigation of a more accurate design, detailed analysis of safety valves with Aspen were studied in my previous study. Simulation technology gives a great deal of useful knowledge. However, it is necessary to verify the simulation results. Therefore, a 40 mL-scale small test instrument with a safety valve was developed, and runaway experiments were carried out in this study. The results of case studies of simulation corresponded to experimental results. Furthermore, this experimental method can estimate the vent size directly without complicated analysis, such as the ISO method or a detailed simulation. In addition, the combination of case studies of the experiment and simulation provides various additional knowledge, such as moderating measure for runway reaction and preventing measure for occurrence of two-phase flow in the reactor. This study contributes to the design of resilient processes for process upsets and will lead to sustainable and economical design.