The alloys K90941 and N08811 were tested under conditions simulating a pyrolysis process of post-consumer plastics. Impurities in the plastic feedstock like chlorine containing materials or organic components yield HCl and H2S respectively during the cracking process. The reactor material must be able to withstand these harsh corrosive conditions.In lab-scale test equipment, process conditions of the reactor zone of the pyrolysis process were simulated at temperatures of 420 °C and 580 °C for 72 h. The gas atmosphere consisted of either 200 ppm or 20000 ppm H2S and 3.8 vol% HCl, 1.9 vol% CO2, 0.3 vol% CO, 2.8 vol% H2, bal. N2. After the corrosion experiments, the samples were analyzed by metallography, SEM/EDX, and XRD. Additionally, the mass loss was evaluated. Results show that the ferritic K90941 is more aggressively attacked than the austenitic N08811 and that for both materials the mass loss rises with increasing H2S content in the gas atmosphere and increasing temperature.
In several industrial processes, metallic materials suffer from chlorine- and sulfur-induced high-temperature corrosion. In previous studies, several steels have been tested at laboratory scale in a simulated gas atmosphere of a pyrolysis process of anthropogenic resources. In this paper, we propose a model on the course of corrosion in a H2S and HCl-containing atmosphere for N10276, which contains, besides iron, chromium, and nickel, also molybdenum as main alloying element. Bearing in mind the impact of the main alloying elements, as well as thermodynamic considerations and kinetic effects, the corrosion behavior of N10276 in a H2S and HCl-containing atmosphere at 480 °C and 680 °C can be explained. In addition, the corrosion behavior of N10276 is compared with earlier tested Fe-Cr-Ni alloys and differences in the corrosion behavior are stated within this paper.
High-temperature corrosion mechanisms in reducing atmospheres containing HCl (3.8 vol%) and a varying amount of H 2 S (0.02 -2 vol%) were developed for several alloys between 420°C and 680°C. These mechanisms are mainly based on practical observations and kinetic considerations-and less on thermodynamic data. This is due to the complexity of these mixed gas atmospheres, volatile corrosion products, and the ever-changing conditions within the corrosion layer, which made it not possible to predict and calculate the actual conditions in the corrosion zone. In this article, a detailed thermodynamic analysis of previously achieved corrosion mechanisms and experimental observations is presented. Correlations and deviations between thermodynamic calculations and practical findings are stated and discussed. The corrosion behavior of ferritic K90941, which performs worse than corrosionresistant austenitic alloys, except for one test condition at 580°C in the atmosphere with 0.2 vol% H 2 S, is explained and supported by thermodynamic data. By combining experiments with thermodynamics, corrosion mechanisms in reducing HCl and H2S-containing atmospheres are explained.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.