Paper details

Title:

Modelling of Boiler Tube Deposit Formation and Deposit Aging for Waste Wood Fired Biomass Boilers

Author(s):

Blank, M., Brunner, T., Obernberger, I.

Document(s):

Abstract:

Deposit formation and associated problems such as fouling and corrosion are crucial when firing waste wood due to its, compared to chemically untreated wood fuels, clearly elevated contents of Na, S, Cl and heavy metals (especially Zn and Pb). In modern waste wood fired boilers based on extreme air staging technology (biomass gasification coupled with gas combustion) these elements are partly released from the fuel to the gas phase during gasification and later provide significant contributions to the formation of boiler tube deposits. To understand the fundamental processes regarding the formation of aerosol deposits on the heat exchanger tubes and their aging (chemical reactions between deposits and flue with a special focus on chlorination and sulphation reactions) a new model has been developed which is presented in this paper. The model transiently simulates changes in deposit build-up and deposit composition in the different boiler sections over defined boiler runtimes. Comparisons with deposit analyses data from a real-scale 40 MW waste wood combustion plant have shown a good agreement with the modelling results. Moreover, the model allows detailed insights into the behaviour of the key elements K, Na, Zn, Pb, S and Cl during deposit formation and deposit aging.

Keywords:

fouling, waste wood, deposit formation, deposit aging, counter-current gasification, gas combustion

Topic:

Biomass Conversion for Bioenergy

Subtopic:

Advanced biomass combustion

Event:

32nd European Biomass Conference and Exhibition

Session:

4CO.15.4

Pages:

517 - 527

ISBN:

978-88-89407-24-0

Paper DOI:

10.5071/32ndEUBCE2024-4CO.15.4

Price:

FREE