Heat-resistant Silicon Carbide Refractories for Gasification Reactors

Gisela Standke, Jörg Adler, Mathias Herrmann, Sören Höhn, Steffen Kunze, Gert Himpel, Heike Heymer

Fraunhofer Institute for Ceramic Technologies and Systems (IKTS), 01277 Dresden/Germany

Revision

Volume 5, Issue 4, Pages 75 - 82

Abstract

New high-efficiency gasification reactors with higher temperatures and pressures and with different temperature cycles than used previously require new types of refractory linings. Besides the oxide materials currently in use, SiC ceramics show great promise as refractories in the reducing atmospheres found in gasifiers. For this reason, recrystallised silicon carbide (RSiC) materials as well as RSiC materials infiltrated with either carbon or ZrO2 were prepared and the corrosion resistance in an acidic ash was investigated at 1300 °C for 100 h in a flowing CO/H2-containing Ar atmosphere. SEM, EDS and XRD analysis of the surfaces and cross sections of the corroded materials revealed the high stability of the modified RSiC materials. Two different mechanisms for corrosion protection were observed. Carbon-infiltrated SiC showed nearly no wettability and very little infiltration of the molten ashes into the RSiC. In contrast, a small amount of slag infiltration was observed for zirconia-infiltrated RSiC materials. At a high degree of pore filling, good protection was obtained through reaction of the ash with zirconia. In all cases no or only minor attack of the SiC skeleton was observed. The results demonstrate the potential of the optimised materials for refractory applications in different environments.

Keywords

recrystallized silicon carbide, RSiC, corrosion, gasification reactors

References

[1] San-Miguel, L.; Schumann, M.; His, C.: High per formance refractories for gasification. refractories WORLDFORUM 3 (2011) 4–7 [2] Gehre, P.; Aneziris, C.G.: Investigation of slag containing refractory materials for gasification processes. J. Europ. Ceram. Soc. 32 (2012) 4041–4042 [3] Private communication by H. Gutte and M. Klinger, TU-BAF 201 [4] Crowley, M.S.: Refractory problems in coal gas - ification reactors. Amer. Ceram. Soc. Bull. 54 (1975) 1072–1074 [5] Dogan, C.P.; et al.: Refractory loss in slagging gasifiers. Proc. UNITECR 2001 (2001) 270– 275 [6] Bonar, J.A.; Kennedy, C.R.; Swaroop, R.B.: Coal-ash slag attack and corrosion of refrac - tories. Amer. Ceram. Soc. Bull. 59 (1980) 473– 478 [7] Poirier, J.; Colombel, L.; Prigent, P.: The corrosion mechanisms of SiC refractory lining in waste incineration plants and in reactors of biomass gasification. Proc. Int. Col. Ref. (2009) 49–52 [8] Salmang, H.; Scholze, H.; Telle, R.: Keramik. 7th Ed. Berlin, Heidelberg, 2007 [9] Dial, R.E.: Refractories for coal gasification and liquefaction. Amer. Ceram. Soc. Bull. 54 (1975) 640–643 [10] Herrmann, M.; et al.: High-temperature corrosion of silicon carbide ceramics by coal ashes. Ceramics Int., in print [11] http://www.rath-group.com, 30 April 2013 [12] Factsage 6.3, Thermfact and GTT-Technology, FactPS Database, 2012 [13] Ewais, E.: Carbon based refractories. J. Ceram. Soc. of Japan 112 (2004) [10] 517–532 [14] Klinger, M.: Internal report. TU Bergakademie Freiberg, Department of Energy Process Engineering and Chemical Engineering, Freiberg/ DE

Copyright

Göller Verlag GmbH