渦旋式流體化床燃燒爐中燃料特性對NOx排放之效應

The Effect of Characteristics of Fuels on NOx emission in a Vortexing Fluidized Bed Combustor

陳致融(Chih-Jung Chen)

指導教授 ： 錢建嵩

中原大學/工學院/化學工程研究所/碩士(2012年)

https://doi.org/10.6840/cycu201200765

摘要

本研究係於一實驗室規模之渦旋式流體化床燃燒爐中進行，其乾舷區內徑為0.154m，高4m，燃燒室截面積為0.22m × 0.11m，二次空氣由乾舷區下方以切線方向進入爐內，其注入點位於分配板上方0.796m。選用六種不同含氮有機化合物分別為吡啶、吡咯、吡酮、精胺酸、硝基苯及醋酸銨，代表各種官能團的形式，探討不同官能團及操作參數對NOx排放濃度的效應。
Svoboda 與Hartman在1991年進行燃燒六種不同含氮有機化合物的實驗，依其結果，作者認為影響NOx生成的主要因素為溫度，次要因素為燃料氮的結構。然而，作者的研究對象大多為環狀結構，缺少與鏈狀結構的比較。因此本實驗選用較多樣氮鍵結形式的六種含氮有機化合物與玉米穗軸混合，配製出氮含量範圍0.5 – 2.0wt%做為研究對象。
結果顯示，不同官能基對NOx排放濃度的影響，相較於燃燒無混合有機化合物的玉米穗軸所排放NOx濃度，燃燒混合吡啶、吡咯及吡酮這類雜環官能團的玉米穗軸，會增加NOx的排放濃度；反之，燃燒混合非雜環類的精胺酸、硝基苯及醋酸銨的玉米穗軸則會減少NOx的排放濃度。而各項操作參數效應方面，NOx的排放濃度會隨床溫、床下計量氧及乾舷區溫度增加而降低，且隨總燃燒過量氧率增加而增加。此外，NOx排放濃度也會隨著燃料氮含量的增加而增加，但在床溫750℃下則無顯著的效應。

關鍵字

氮氧化物 ； 燃料特性 ； 流體化床

並列摘要

A bench-scale vortexing fluidized bed combustor (VFBC) was set up in this study. The combustor cross area is 0.22 × 0.11 m2, and the freeboard is in 0.154 m I.D. and 4 m height. The secondary air injected nozzles were installed tangentially at the bottom of freeboard. Model compounds containing nitrogen was pyridine, pyrrole, pyridone, arginine, nitrobezene, ammonium acetate used as the fuel in this study. The effects of different functional groups and various operating parameters on NOx emission were investigated.
Svoboda and Hartman(1991) used toluene to mix with six organic compounds contant nitrogen and be burned in a laboratory fluidized bed reactor. According to result, they think that effect of temperature on NOx emission is major factor and the structure of fuel-N is minor. However, most model compounds that they used is cyclic structure and lack comparison with the linear structure. Therefor, this experimant uesd corncob to mixed with various nitrogen functional groups. The nitrogen contant in the model mixtures varied within the range 0.5-2 wt%.
The result show that heterocyclic aromatic groups including pyridine, pyrrole, pyridone can increase NOx emission. But non- heterocyclic aromatic groups including arginine, nitrobezene, ammonium acetate make NOx emission decreace. For various operating parameters, NOx emission decreased as bed temperature, stoichiometric oxygen ratio in the bed and freeboard temperature increased and increase as excess air ratio increased. In addition, NOx emission increase as nitrogen contant of fuel increased, but is insignificant effect under bed temperature 750℃.

並列關鍵字

fluidized bed ； model compound ； combustion

參考文獻

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