Title: Recent Advances in Refractory Concrete Technology
Author(s): Wate T. Bakker
Publication: Symposium Paper
Appears on pages(s): 1-16
Keywords: Aluminum oxide; anchors(fasteners); bonding; calcium aluminates; clay minerals; coal gasification; compressive strength; computer programs; corrosion resistance; cracking(fracturing); creep properties; curing; dehydration; drying; feldspars; fire-cays.
Recent research on refractory concretes for use in energy conversion applications has provided data, useful in other areas. It is shown that refractory concretes, especially those containing a calcined fireclay aggregate, are very tolerant to environments, generally considered corrosive, such as gases containing CO, CO2, H2, H2S and steam at high pressures. Even when the hydrated calcium aluminates are decomposed and some of the CaO is leached out, are fractory with acceptable physical properties remains. In many cases the strength of the material increases during service.
Improved design methods for refractory concrete were also developed. A computer program to calculate heat losses from refractory concrete lined pressure vessels was developed and experimentally verified. This model takes into account the effect of cracks, anchor spacing and different gases in the pores of the concrete. The thermo mechanical behavior of refractory concrete was studied experimentally and modeled by computer. Design and materials selection criteria were developed. To minimize cracking, shrinkage and creep of the concrete should be low, preferably less than 0.1%. Anchor spacing should be wide and the anchors coated with a compliant or combustible material to avoid stress concentrations. Bond barriers between the vessel shell and the refractory and between various refractory layers are also beneficial. Long holding periods during initial heat up of the lining were found superfluous.