Modeling the Use of Sulfate Additives for Potassium Chloride Destruction in Biomass Combustion

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• 作者：Hao Wu ; Morten Nedergaard Pedersen ; Jacob Boll Jespersen ; Martti Aho ; Juha Roppo ; Flemming Jappe Frandsen ; Peter Glarborg
• 刊名：Energy & Fuels
• 出版年：2014
• 出版时间：January 16, 2014
• 年：2014
• 卷：28
• 期：1
• 页码：199-207
• 全文大小：470K
• ISSN：1520-5029

文摘

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 and HCl. In the present study, the rate constants for decomposition of ammonium sulfate and aluminum sulfate were obtained from experiments in a fast heating rate thermogravimetric analyzer. The yields of SO₂ and SO₃ from the decomposition were investigated in a tube reactor at 600鈥?00 掳C, revealing a constant distribution of about 15% SO₂ and 85% SO₃ from aluminum sulfate decomposition and a temperature-dependent distribution of SO₂ and SO₃ from ammonium sulfate decomposition. On the basis of these data as well as earlier results, a detailed chemical kinetic model for sulfation of KCl by a range of sulfate additives was established. Modeling results were compared to biomass combustion experiments in a bubbling fluidized-bed reactor using ammonium sulfate, aluminum sulfate, and ferric sulfate as additives. The simulation results for ammonium sulfate and ferric sulfate addition compared favorably to the experiments. The predictions for aluminum sulfate addition were only partly in agreement with the experimental results, implying a need for further investigations. Predictions for the effectiveness of the sulfur-based additives indicate that ferric sulfate and ammonium sulfate have similar effectiveness at temperatures ranging from approximately 850 to 900 掳C, whereas ferric sulfate is more efficient at higher temperatures and ammonium sulfate is more effective at lower temperatures.