渦旋式流體化床燃燒爐中燃燒木屑之研究

The Study of Sawdust Combustion in a Vortexing Fluidized Bed Combustor

蘇冠彰(kuan-chang Su)

指導教授 ： 錢建嵩

中原大學/工學院/化學工程學系/碩士(2006年)

https://doi.org/10.6840/CYCU.2006.00385

摘要

為探討木屑於渦旋式流體化床燃燒爐之燃燒行為，本研究係於一總高4.6 m、底面積0.8 m×0.4 m之渦旋式流體化床燃燒爐中進行實驗。以床內熱傳管水或噴控制床溫，並改變各操作變數，探討各操作條件對各區段之燃燒份額、燃燒效率與溫度分佈的影響。
實驗結果顯示，由於木屑粒子輕且高揮發物含量，因此大部分燃燒於床表面上方進行，造成飛濺區之燃燒份額具較高比例。於固定總空氣量，改變一、二次配風比時，一次風比例越高，飛濺區之燃燒份額越高，亦使細粒子淘淅現象增加，導致燃燒效率降低。反之，二次風增加時，因二次風渦旋效應致使粒子停滯時間增加及擾流度增大，使二次風區之燃燒份額提高。當過量空氣增加時，因二次風區渦旋效應提高，使二次風區與飛濺區的燃燒份額和燃燒效率隨之增加。

關鍵字

木屑 ； 流體化床燃燒爐 ； 生質燃料

並列摘要

In order to understand the combustion phenomena within a vortexing fluidized bed combustor (VFBC), an experiment is conducted in a combustor with a cross-section of 0.76 m × 0.4 m and a height of 4.6 m. The sawdust, a residual product from the timber industry, is used as fuel. The temperature within the combustor is controlled by water injection or the heat transfer tube in the bed. The effects of various parameters on the combustion efficiency, temperature distribution, and combustion proportion are investigated.
The results have shown that the combustion mainly takes place in the splashing zone, where the temperature is higher than that in the other zones. The more the primary air is, the more heat is released in the splashing zone, and the more active the elutriation of the particle is observed. However, the active elutriation reduces combustion efficiency. On the other hand, the more the second air is, the more the retention time of the particles will be, thus, increasing the heating release ratio in the second air zone and the freeboard zone. The study also shows that when excess air increases, the second air zone has enough oxygen to react with the fuel so the combustion efficiency and heating ratio rise in the freeboard zone.

並列關鍵字

fluidized combustor ； sawdust ； biomass

參考文獻

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