間歇式進料對先導型流體化床焚化爐中 燃燒行為之效應

The Study of Combustion Behavior in A Pilot Scale Fluidized Bed Incinerator with Intermittence Batch Feeding.

陳學融(Hsueh-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(2009年)

https://doi.org/10.6840/CYCU.2009.00739

摘要

中 文 摘 要
一般大型焚化爐都以連續進料燃燒，鮮少使用間歇式進料燃燒。而在處理特殊的有害廢棄物，如醫療廢棄物，係因具危害性，而不可進行切割、破碎等處理，則必須採取批次或間歇式進料於焚化爐內燃燒，以防有害物質外漏釀成災害，因此本研究選用此方法進行實驗。
本研究於一總高4.6 m，乾舷區內徑0.75 m，燃燒室為0.8 m × 0.4 m之渦旋式流體化床焚化爐(Vortexing Fluidized Bed Incineration, VFBI)中以大型木塊( 10.5 cm × 28 cm)與橡膠球( 9.4 cm)進行研究，採取間歇式進料，模擬不同廢棄物於間歇式進料流體化床焚化爐中對其燃燒行為之影響。並藉由改變操作參數如：投料時間間隔、靜床高與床下計量氧比，探討操作參數對於溫度分佈與氣態污染物NOx跟CO的關係，以瞭解爐內之燃燒情形。
本研究以橡膠模擬人工廢棄物並利用回應曲面法(RSM)進行分析，而以木頭模擬天然廢棄物利用單因子分析以進行對照。結果顯示，爐內溫度會隨進料時間點改變而呈現週期變化，最高溫度出現於飛濺區。橡膠於床內燃燒對於每次投料後爐內床溫會出現兩階段的溫度上升，前者代表揮發物之釋放與燃燒，後者則為固定碳燃燒所帶來之熱量變化。
燃燒橡膠時，經因子效應顯著性檢定顯示，床下計量氧比則對於爐出口CO平均濃度之影響較大；但各操作參數對於爐出口NOx平均濃度之效應則較不明顯，皆低於90%信心水準。燃燒木頭時，爐出口CO平均濃度隨著床下計量氧比增加而呈現先升後降之趨勢。靜床高增加，CO濃度有先降後升之變化。進料時間間隔拉長時，CO濃度亦隨時間間隔增加而上升。改變床下計量比或進料時間間隔對於爐出口NOx影響較不明顯，但在最高之靜床高下，NOx濃度則較高。
以爐出口CO濃度最低之前提下，以橡膠與木頭為進料物之最適化操作條件為：床下風量=3 Nm3/min，二次風風量＝1.5 Nm3/min，過量空氣80%，靜床高＝38cm，進料時間間隔＝1batch/10min，橡膠需操作於床下計量氧比為100%，而木頭則操作於床下計量氧比為140%。

關鍵字

間歇式 ； 流體化床焚化爐

並列摘要

Abstract
It always uses continuous feeding in incinerator. In medical waste combustion which is usually enwrapped in package to prevent hazardous material emitting to the environment. Intermittent batch feeding is applied for this kind feeding material.
In this study, all the experiments were carried out in a pilot scale vortexing fluidized bed incineration of 0.75 m I.D. and 4.6 m in height. The intermittent feeding was used in this investigation. The woodblock (ø 10.5 cm × 28 cm) and Rubber (ø 9.4 cm) were used as feeding material to simulate the artificial and nature waste, also silica sand was employed as the bed material. The effects of various operating conditions on mean bed temperature, mean freeboard temperature, mean CO and NOx emissions were investigated. The operating parameters including under bed stoichiometric ratio, static bed height and interval time of feeding were studied.
The experimental results show that the highest temperature of the incinerator takes place in splash zone. There are two stages increasing in the bed temperature when rubber is as the fuel. It can be attributed to the combustion in the first stage. Then the char burns in the second stage. In rubber combustion, the CO emission increase with under bed stoichiometric ratio or interval time of feeding. But it increase first and then decreasing with static bed height increasing. The NOx emission increase with static bed height increasing. But it also rises first and then decreasing in interval time of feeding increasing. The NOx emission in the 140% under bed stoichiometric ratio is the lowest in different under bed stoichiometric ratio. In the woodblock combustion process, the CO emission increases with interval time of feeding increasing. The CO emission rises first and then decreasing with under bed stoichiometric ratio. But it is opposite tendency in static bed height increasing. In NOx emission, the effect with under bed stoichiometric ratio and interval of feeding times is not significant. It is the highest NOx emission in the highest static bed height. The optimum operating condition for the experiments are primary air=3Nm3/min, second air flow rate=1.5Nm3/min, excess oxygen 80%, static bed height 38cm, 140% under bed stoichiometric ratio for woodblock and 100% under bed stoichiometric ratio for rubber.

並列關鍵字

Fluidized Bed Incinerator ； Intermittence Batch Feeding

參考文獻

顏維生，《流體化床燃燒爐中醋酸對氮氧化物排放之效應》，私立中原大學化學工程學系碩士論文，(2008)。

Anthony, E. J., “Fluidized Bed Combustion of Alternative Solid Fuels; Status Successes and Problems of the Technology,” Progr. Energy Combust. Sci. 21, 239-268 (1995).

Atimtay , T. Aysel and H. Topal, “Co-combustion of olive cake with lignite coal in a circulating fluidized bed,’’ Fuel 83, 859-867 (2004)

Atimtay , T. Aysel and K. Burçak,“ Co-combustion of peach and apricot stone with coal in a bubbling fluidized bed,’’ Fuel Process. Technol. 89, 183-197 (2008)

Abelha, P., I. Gulyurtlu and I. Carbrita, “Release of nitrogen precursors from coal and biomass residues in a bubbling fluidized bed,” Energy and Fuels 22, 363-371 (2008).