Title:
Modeling the Use of Sulfate Additives for Potassium Chloride Destruction in Biomass Combustion
Author(s):
Wu, H., Nedergaard, M., Jespersen, J.B., Aho, M., Frandsen, F., Glarborg, P.
Document(s):
Paper
Abstract:
Potassium chloride, KCl, formed from biomass combustion may lead to ash deposition and corrosion problems in boilers. Sulfates are effective additives for converting KCl to the less harmful K2SO4. In the present study, the decomposition of ammonium sulfate, aluminum sulfate and ferric sulfate was studied respectively in a fastheating rate thermogravimetric analyzer (TGA) for deriving a kinetic model. The yields of SO2 and SO3 from the decomposition were studied in a tube reactor, revealing that the ratio of the SO3/SO2 released varied for different sulfate and for ammonium sulfate the ratio was affected by the decomposition temperature. Based on the experimental data, a model was proposed to simulate the sulfation of KCl by different sulfate addition, and the simulation results were compared with pilotscale experiments conducted in a bubbling fluidized bed reactor. The simulation results of ammonium sulfate addition and ferric sulfation addition compared favorably with the experimental results. However, the model for aluminum sulfate addition underpredicted significantly the high sulfation degree of KCl observed in the experiments, possibly because of an underestimation of the decomposition rate of aluminum. Under the boiler conditions of the present work, the simulation results suggested that the desirable temperature for the ferric sulfate injection was around 950900 °C, whereas for ammonium sulfate the preferable injection temperature was below 800 °C.
Keywords:
alkali, biomass, combustion, modelling, additives, ashes, modeling
Topic:
R&D on Biomass Conversion Technologies for Heating, Electricity and Chemicals
Subtopic:
Solid biofuel combustion for small and medium scale applications
Event:
21st European Biomass Conference and Exhibition
Session:
2CO.10.2
Pages:
595 - 601
ISBN:
978-88-89407-53-0
Paper DOI:
10.5071/21stEUBCE2013-2CO.10.2
Price:
FREE
