Surface adhesion of low rank coal ash: (Quarterly technical progress report): October 1-December 31, 1986

Technical Report · Sun Feb 01 04:00:00 EST 1987

OSTI ID:6535300

Austin, L G; Conn, R E

Darco (TX) lignite was ion-exchanged with ammonium acetate. The amount of ASTM ash (dry basis) was reduced from 11.3 to 7.1 wt % after the lignite was ion-exchanged. The amount of exchangeable sodium and calcium were found to be 90% and 78%, respectively. The gas-fired drop tube furnace was used to produce deposits with raw and ion-exchanged Darco lignite on mild steel substrates at conditions similar to those producing utility boiler slagging. The hot zone temperature was held at 1500/sup 0/C and the constrictor temperature was held at 1300/sup 0/C for these tests. The estimated particle residence time within the hot zone was approximately one to two seconds. The sticking fraction of the Darco lignite ash was 0.45 for a 20 minute test duration and a feed rate of 0.35 g/minute. The resultant deposit was very fused at the top and had a high strength (>5.5 MPa). Increasing the oxygen partial pressure to 60% did not have a significant effect on deposit formation rate or strength for Darco lignite. The electrically-heated drop furnace was used to form deposits with raw and ion-exchanged Darco lignite on stainless steel substrates at conditions similar to those producing utility boiler convective fouling. The hot zone temperature and constrictor temperature were held at 1500/sup 0/C and 1200/sup 0/C, respectively. The estimated particle residence time within the hot zone was about 2.0 to 3.5 seconds. The gas velocity at the constrictor was held at 15 m/second. The sticking fraction of the Darco lignite ash was 0.42 for a 20 minute test period; the resultant deposit was strongly sintered at the top and had a moderate strength of 2 to 6 MPa.

• Research Organization: Pennsylvania State Univ., University Park (USA). Coll. of Earth and Mineral Sciences
• DOE Contract Number: AC21-85FC10627
• OSTI ID: 6535300
• Report Number(s): DOE/FC/10627-2361; ON: DE87011271
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
014000* -- Coal
Lignite
& Peat-- Combustion
20 FOSSIL-FUELED POWER PLANTS
200101 -- Fossil-Fueled Power Plants-- Cooling & Heat Transfer Equipment & Systems
ADHESION
ALLOYS
ASH CONTENT
ASHES
BOILERS
BROWN COAL
CARBONACEOUS MATERIALS
CHEMICAL REACTIONS
CHROMIUM ALLOYS
COAL
COHERENT SCATTERING
COMBUSTION
CORRELATIONS
CORROSION RESISTANT ALLOYS
DEPOSITION
DEPOSITS
DIFFRACTION
ELEMENTS
ENERGY SOURCES
FOSSIL FUELS
FOULING
FUELS
ION EXCHANGE
IRON ALLOYS
IRON BASE ALLOYS
LIGNITE
MATERIALS
MECHANICAL PROPERTIES
MELTING
NONMETALS
OXIDATION
OXYGEN
PARTIAL PRESSURE
PHASE TRANSFORMATIONS
RESIDUES
SCATTERING
STAINLESS STEELS
STEELS
THERMOCHEMICAL PROCESSES
X-RAY DIFFRACTION