Durability testing of ceramic candle filters in pressurized-fluidized bed combustion environments

Ceramic candle filters were subjected to 500 hour high temperature/ high pressure (HTHP) exposure tests to examine their extended durability in simulated coal pressurized-fluidized bed combustion (PFBC) environments. The candle filter materials analyzed included two SiC filters, one with clay binder and one with a minimal amount of clay binder, a cordierite filter, a mullite candle filter and an aluminosilicate refractory concrete filter. Exposure testing conditions included a range of temperature from 700-850°C and a pressure ranging from 1.7-1.8 MPa. The HTHP tests included exposing the ceramic filter materials to steam and steam-alkali environments. The presence of alkali significantly accelerated the deterioration of the filters. The results of the analysis show that significant crushing strength losses were exhibited by the SiC filters after exposure to HTHP alkali-steam conditions at temperatures as low as 700°C. The expansive and destructive cristobalite phase developed in the SiC filters after most of the treatments. The cordierite candle filter showed a decrease in crushing strength associated with grain growth after each high temperature exposure but few other signs of deterioration were detected. The mullite candle filter and the refractory concrete candle filter showed the least amount of change in crushing strength and overall the most candle stability.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Materials Science and Engineering

Department dc:contributor.department

Materials Science and Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

1993

Author dc:creator

• Valentino, Karen Rose

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Dc Identifier Other

etd-04252009-040418

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/42200