Mechanisms of fouling, slagging and corrosion by pulverized coal combustion

Technical Report · Fri Jun 01 04:00:00 EDT 1984

OSTI ID:5875208

Hsu, L L; Kubarych, K G; Stetson, A R; Metcalfe, A G

The objective of this program is to conduct a detailed and comprehensive study of the mechanisms of fouling, slagging and corrosion in pulverized coal combustors by employing well controlled model systems which simulate the coal combustion environment. A combustion test rig was designed, constructed and calibrated for parametric tests in which the following variables were evaluated: Non-condensing alkali (NaCl), condensing alkali (Na/sub 2/SO/sub 4/, K/sub 2/SO/sub 4/), alkali ratio (Na/K) - melting point depression, inert particles (Al/sub 2/O/sub 3/), reactive particles (SiO/sub 2/ and Fe/sub 2/O/sub 3/), ash viscosity (SiO/sub 2/, Al/sub 2/O/sub 3/, CaO, Fe/sub 2/O/sub 3/ glasses), sulfur (SOx gas, SO/sub 4//sup 2 -/), incomplete combustion - reducing agent (carbon), reactive surface area (SiO/sub 2/ particle size > standard SiO/sub 2/ particle size), gas stream and particle velocity, and tube material and tube temperature. Four target tube materials were employed: SiC (2000/sup 0/F), Hastelloy X (1600/sup 0/F), Croloy (1100/sup 0/F) and SA-210 (800/sup 0/F). Particulate fouling species used in the rig tests ranged from SiO/sub 2/ and Al/sub 2/O/sub 3/ to complex glasses simulating coal ash. In reviewing the wealth of information generated in the test program, a number of significant findings emerge as being most urgent to fouling/slagging: Target tube temperature, viscosity profile, fouling medium particle size and shape, reactivity of fouling medium, aerodynamic flow, dewpoint/condensation of sulfates, particle loading rate, and surface finish. Four approaches are recommended as being potentially capable of reducing fouling and slagging: Chemical control, mechanical erosion (deposit removal), aerodynamic optimization, and elimination of tube corrosion by ceramic coatings. 46 refs., 105 figs., 23 tabs.

• Research Organization: Solar Turbines, Inc., San Diego, CA (USA)
• DOE Contract Number: AC22-81PC40272
• OSTI ID: 5875208
• Report Number(s): DOE/PC/40272-8; ON: DE85008002
• Country of Publication: United States
• Language: English

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