Abstract
Reactions and transformations that result in chemical degradation of castable refractories used as liners for coal gasification reactors have been studied. In addition to phase analysis of laboratory and pilot plant specimens by conventional X-ray powder diffraction, a new test method was developed that permits changes in the phase composition to be observed without removing the specimen from the test atmosphere. Two candidate castable refractories were included in the study, a high purity CaO-Al2O3 composition with tabular alumina aggregate (93.7 wt pct Al2O3, 5.6 wt pct CaO) and a CaO-Al2O,- SiO2 composition with calcined kaolinite aggregate (55 wt pct Al2O3, 36 wt pet SiO2, 5 wt pct CaO). Specimens were exposed to steam, steam/CO2, and a simulated coal gasification atmosphere at a pressure of 7 M Pa (1000 psig) and temperatures up to 1000 °C. Frequent changes in the bonding phases, and intervals in which a bonding phase was in transition were observed in the case of the high purity castable refractory. The silicacontaining refractory, on the other hand, formed bonding phases which were stable in steam over a large range of temperatures and pressures.
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Robbins, C.R., Mauer, F.A. Chemical degradation of castable refractories in coal gasification process environments. JMES 3, 32–42 (1981). https://doi.org/10.1007/BF02833527
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DOI: https://doi.org/10.1007/BF02833527