Learning from Failure: An Attempt to Measure Dissolution Kinetics of High-Chromia Refractories by Petcoke-Derived...

Gasifying petroleum coke (petcoke) offers a promising route to low-carbon energy, hydrogen, and chemical intermediates. However, vanadium- and iron-rich slags aggressively corrode high-chromia refractories in entrained-flow gasifiers, shortening service life and increasing maintenance costs. To address this, we developed an in situ high-temperature X-ray diffraction (HT-XRD) protocol, which involved failure analysis of previous experiments, to attempt the measurement of dissolution kinetics at the liquid petcoke slag/solid high chromia refractory interface under gasifier-relevant conditions (1500 °C, 70% CO-30% CO₂). Thermodynamic modeling (FactSage 8.3, 1100-1500 °C) predicted Pt stability under the defined conditions, and testing in a furnace on unstrained Pt under similar conditions confirmed these predictions; however, experiments performed on the Pt heating strip on an Anton Paar HTK2000 nonambient chamber contradicted these predictions with premature failure of the Pt heating strip. We believe this is related to interfacial reactions with slag/refractory species occurring under tensile stress. SEM-EDS confirmed Pt interdiffusion with Cr, Al, and Si. The addition of a MgO (110) single crystal between the Pt strip and the refractory eliminated this issue and provided a simple, low-cost solution that enabled stable isothermal runs up to just under 2 h. In theory, XRD peak-area decay of Cr₂O₃ should yield time-resolved consumption rates and enable accelerated screening of refractory and slag chemistries. In reality, we were unable to see a significant Cr₂O₃ XRD peak decay under the conditions achievable with the available instrumentation. Improvements in nonambient stage designsuch as enhanced thermal stability and longer high-temperature operation available on newer versions of this nonambient chamber from Anton Paar and lessons learned from this research could further expand the technique's utility across industrial corrosion studies.