Shedding light on the governing mechanisms for insufficient CO and H2 burnout in the presence of potassium, chlorine and sulfur

FUEL

卷:273

Article

Vilches, Teresa Berdugo¹  Weng, Wubin²  Glarborg, Peter³  Li, Zhongshan²  Thunman, Henrik¹  Seemann, Martin¹ 

[1] Chalmers Tekniska Hgsk, Div Energy Technol, Gothenburg, Sweden

[2] Lund Univ, Div Combust Phys, POB 118, S-22100 Lund, Sweden

[3] Tech Univ Denmark, Chem Engn, DK-2800 Lyngby, Denmark

关键词: CO oxidation;    Potassium;    Inhibition;    Combustion;    UV absorption spectroscopy;    TDLAS;   

DOI  :  10.1016/j.fuel.2020.117762

来源: Elsevier

【 摘 要 】

Based on the experiences of insufficient burnout in industrial fluidized bed furnaces despite adequate mixing and availability of oxidizer, the influence of potassium on CO and H-2 oxidation in combustion environments was investigated. The combustion environments were provided by a laminar flame burner in a range relevant to industrial furnaces, i.e. 845 degrees C to 1275 degrees C and excess air ratios ranging from 1.05 to 1.65. Potassium, in the form of KOH, was homogeneously introduced into the hot gas environments to investigate its effect on the radical pool. To quantitatively determine key species that are involved in the oxidation mechanism (CO, H-2, KOH, OH radicals, K atoms), a combination of measurement systems was applied: micro-gas chromatography, broadband UV absorption spectroscopy and tunable diode laser absorption spectroscopy. The inhibition effect of potassium on CO and H-2 oxidation in excess air was experimentally confirmed and attributed to the chain-terminating reaction between KOH, K atoms and OH radicals, which enhanced the OH radical consumption. The addition of chlorine or sulfur could reduce the concentrations of KOH and K atoms and consequently eliminated the inhibition on CO and H-2 oxidation. Existing kinetic mechanisms underestimate the inhibiting effect of potassium and they fail to predict the effect of temperature on CO and H-2 concentration when potassium and sulfur coexist. This work advances the need to revise existing kinetic mechanisms to fully capture the interplay of K and S in the oxidation of CO and H-2 in industrial fluidized bed furnaces.

【 授权许可】

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