Explosion Protection Concept for a Production Scale Reaction in a Pure Oxygen Atmosphere Explosionsschutzkonzept einer Reaktion in Sauerstoffatmosphäre im Produktionsmassstab

Abstract

The implementation of a catalyzed oxidation, as part of a new production plant launch, describes a challenging situation with regard to safety requirements. The reaction runs under a low pressure of pure oxygen. In order not to accumulate undesired byproducts during the reaction, a continuous purge stream removes such compounds. Without a well-founded safety concept, a pure oxygen atmosphere, solvent vapour and an exothermic reaction could result in a highly explosive mixture. This could be due to an ignition spark, in particular at reduced minimum ignition energy in pure oxygen. Due to the lack of information from the literature, further trials have been conducted to gain more safety data. Various single tests and simulated series of experiments have been adopted as a basis for the plant & process design. Data could be gained from the purge-pipe detonation on the vessel top, the flame speed and from the maximum explosion pressure. The explosion-protection concept resulting from the above trials includes the following: a) The oxidation vessel needs to have an explosion-resistant construction; b) decoupling the explosion is enabled by reducing pressure with a flame interrupter and an explosion barrier, a so-called fast acting valve; c) the production steps prior and after the oxidation step are protected through inertisation and follow the concept of avoiding inflammable atmospheres.