Characterization and Failure Analysis of Ceramic Filters Utilized for Emission Control Coal Gasification

Technical Report · Sun Mar 01 04:00:00 EST 1998

DOI:https://doi.org/10.2172/2223· OSTI ID:2223

Mei, Daniel ^[1]; Zhou, Jianren; Huque, Ziaul

---

1. Federal Energy Technology Cente

Advanced integrated gasification combined cycle (IGCC) and pressurized fluidized bed combustion (PFBC) power system requires both hot gas desulfurization and particulate filtration to improve system thermal efficiency and overall performance. Therefore, effective high temperature ceramic filters are indispensable key component in both of the advanced IGCC and PFBC coal based power systems to perform hot gas cleanup work. To meet the environmental particulate emission requirements and improve thermal efficiency, ceramic filters are mainly utilized to cleanup the hot gas particulate to protect downstream heat exchanger and gas turbine components from fouling and corrosion. The mechanical integrity of ceramic filters and an efficient dust cake removal system are the key issues for hot gas cleanup systems. The filters must survive combined stresses due to mechanical, thermal, chemical and steam attack throughout normal operations (cold back pulse cleaning jets), unexpected excessive ash accumulation, and the start up and shut down conditions. To evaluate the design and performance of ceramic filters, different long term filter testing programs were conducted. To fulfill this purpose, two Advanced Particle Filter (APF) systems were complete at Tidd PFBC Demonstration Plant, in Brilliant, Ohio in late 1990 as part of the Department of Energy's (DOE) Clean Coal Technology Program. But the most undesirable thing ever happened was the sudden functional and physical failures of filters prior to its designed life time. In Tidd APF filter vessel, twenty eight (28) filters failed one time. Significant research effort has been carried out to find out the causes that led to the early failure of filters. In this work, the studies are emphasized on the possible failure causes analysis of rigid ceramic candle filters. The objectives of this program were to provide an systematic study on the characterization of filters, material laboratory analysis on filter micro-structure, the dust cake dislodging mechanism and possible causes led to failures of ceramic filters. These research work includes 1) characterization on filter properties, 2) material laboratory investigation on cracked and un-cracked filter batches, 3) a thermal numerical simulation, 4) various physical testing on filter mechanical integrity and 5) the back pulse cleaning mechanism. These studies provide insights into variations of filter permeability, filter toughness against different mechanical loading impact, microstructure changes of filters, coal ash bridging and micro-thermal cracks induced during the cold back pulse cleaning process. To characterize the physical properties of used and unused ceramic filters, filter permeabilities and the pressure field of the gas stream were measured within a filter chamber with the use of fast response pressure transducers and an automatic data acquisition system. Used filters displayed non-uniform permeability distribution along its axis; and these variations developed asymmetric flow pattern in the filter chamber.

• Research Organization: Federal Energy Technology Center, Morgantown, WV, and Pittsburgh, PA
• Sponsoring Organization: USDOE
• DOE Contract Number: FG21-94MC31203
• OSTI ID: 2223
• Report Number(s): DE-FG21-94MC31203--99; ON: DE00002223
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
Ceramics
Coal
Filters
Gasification