Chemical reaction conditions in a Danish 80 MW{sub th} CFB-boiler co-firing straw and coal

Conference · Wed Dec 31 04:00:00 EST 1997

OSTI ID:355827

Hansen, P F.B. ^[1]; Lin, W; Dam-Johansen, K ^[2]

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1. Power Co. I/S Midtkraft, Aarhus (Denmark)
2. Technical Univ. of Denmark, Lyngby (Denmark). Dept. of Chemical Engineering

Future boilers to be constructed in Denmark including boilers intended for energy conversion of biomass (straw and wood chips) will be designed for Ultra Super Critical steam data. The high steam temperatures and subsequently metal temperatures in the superheaters will increase the corrosion hazard significantly. Severe superheater corrosion observed in the convective path and on test tubes inserted into the loop seal of a Danish 80 MW{sub th} Ahlstroem Pyroflow CFB boiler co-firing coal and straw initiated this study on the conditions under which the chemical reactions occur and deposits form. Load changes--caused by variations in public demand for district heating shifts the reaction conditions in the loop seal between predominantly reducing and predominantly oxidizing conditions. Furthermore the external particle circulation rate and the local temperatures are strongly affected. Deposits collected in the loop seal on temperature controlled probes reveals Cl concentrations more than Twenty Thousand times higher than found in the surrounding bed material. The results are discussed and suggestions on how to reduce high temperature corrosion and superheater fouling are presented.

• OSTI ID: 355827
• Report Number(s): CONF-9705116--; ISBN 0-7918-1557-9
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
09 BIOMASS FUELS
36 MATERIALS SCIENCE
CHLORINE
CHROMIUM-MOLYBDENUM STEELS
COAL
COCOMBUSTION
CORROSION
FLUIDIZED BED BOILERS
STEEL-CR18NI12
STRAW
SUPERHEATERS
WOOD WASTES