A CASE STUDY OF A SYNTHESIS GAS SYSTEM (H2) FAILURE IN AN AMMONIA PRODUCTION FACILITY

Abstract

The effect of pressurized hydrogen on pipeline walls is an important phenomenon that can cause damage to the integrity of the pipeline structure during transport and storage of gases. Hydrogen can penetrate the wall of metallic pipelines (alloy steel or carbon steel) and cause cracking or rupture of the material, which can lead to pressure loss or even serious effects (explosions, fires). The embrittlement of the metal by hydrogen is a phenomenon of degradation of the mechanical properties of the metal, as a result of the penetration of hydrogen into the crystalline structure of the metal, by diffusion, leading to the weakening of the atomic bonds, and then to the decrease in the ductility of the material, manifested by cracking or breaking it in areas exposed to mechanical stress or vibrations. The article aims to present a case study, starting from a recent failure of a synthetic gas (H2) system within an ammonia production facility at a chemical plant in Romania, consisting of an explosion followed by a fire, the support being synthesis gas (mainly H2, 70%), gas escaping through the crack created in a pipe in the welding joint area, where the working pressure was about 140 bar. The mechanism of the event was elaborated on the basis of the material made available by the research bodies, the results obtained by the expertise of the material samples at the scene and in the laboratory, as well as the relevant technical-scientific reasoning.