CCS AND POWER SYSTEMS
ADVANCED ENERGY SYSTEMS - GASIFICATION SYSTEMS
LONG-TERM CANDLE FILTER TESTS
Performer: Southern Company Services, Inc.
Project No: NT0000749
- Extensive testing with ceramic, composite, sintered metal powder, and sintered metal fiber elements has shown that the mass concentration of gasification ash can be reduced from 10,000–30,000 parts per million by weight (ppmw) at the filter inlet to less than 0.1 ppmw at the filter outlet. Experience at the PSDF has shown that ceramic filter elements are prone to crack and fail during thermal excursions associated with coal feeder trips and other system upsets. To avoid these failures, recent testing at the PSDF has focused on metal filter elements.
- Since initiating gasification operations in 1999, multiple test campaigns, each 250 to 1,500 hours in duration, have been completed. During this time, the PCD candle filters have been consistently reliable and available for testing, demonstrating collection efficiencies greater than 99.999 percent.
- To date, iron aluminide sintered metal powder elements and Haynes HR-160 sintered metal fiber elements have the longest exposure times. Progressive corrosion and an increase in pressure drop have been noted in the iron aluminide elements, although the corrosion has not had significant impact on mechanical integrity of the filter media. Less corrosion or plugging has been found in the HR-160 elements, but they also have had much less exposure time than have the iron aluminide elements.
- Accomplishments at the PSDF in fail-safe development include the following: (1) new types of fail-safes were developed; (2) the fail-safe concept in the particulate control device (PCD) for Integrated Gasification Combined Cycle technology was promoted and vendors were motivated and supported to develop new fail-safes per PSDF test results and specifications; (3) fail-safes from PSDF’s own design and from vendors were tested systematically under actual gasification operating conditions; and (4) fail-safes were eventually incorporated into the commercial PCDs as a standard and required item.