廢棄活性碳於TGA及流體化床中燃燒之研究

A Study of Spent Activated Carbon Combustion in TGA and Fluidized Bed

王志庭(Jing-Ting Wang)

指導教授 ： 錢建嵩

中原大學/工學院/化學工程研究所/碩士(2013年)

https://doi.org/10.6840/cycu201300987

摘要

本研究分為兩部分，先以TGA計算廢棄活性碳於不同溫度之活化能，其次於實驗室規模之渦旋式流體化床燃燒爐中進行，其高4m，燃燒室截面積為0.22 m × 0.11m，乾舷區內徑為0.154 m，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0.796 m。選用汙水處理之廢棄活性碳為燃料，探討不同操作參數對床溫及CO排放濃度的效應。
結果顯示出廢棄活性碳熱值約4700 kcal/kg，活化能約為300 kJ/mol，活化能隨著溫度、氧濃度增加而減少，粒徑對於活化能則沒有影響，於VFBC燃燒之下證明廢棄活性碳是可以燃燒的。各操作條件對床溫及CO排放濃度之影響，由P-value顯示出床下計量氧率影響效應最大，過量氧率對床溫影響最小，隨著床下計量氧增加，會造成床溫升高，CO濃度排放下降。隨著配風比值增加，會造成床溫下降，CO濃度排放增加。操作條件對床區燃燒份額及乾舷區燃燒份額之影響，床區燃燒份額隨著床下計量氧率增加而增加，乾舷區燃燒份額則相對的減少; 床區燃燒份額隨著配風比值及過量氧率增加而減少，乾舷區燃燒份額則相對的增加，其中床下計量氧率影響效應最大。
整體而言，廢棄活性碳於VFBC燃燒，在不控制床溫之下，操作條件為配風比值1.08且床下計量氧率90%時為最佳操作條件，能有效降低CO濃度排放，但床溫則達到950℃以上。

關鍵字

廢棄活性碳 ； 流體化床

並列摘要

This study entails TGA activation energy calculation and bench-scale vortexing fluidized bed combustion (VFBC). The combustor cross section is 0.22 m × 0.11 m, and the freeboard is 4 m height and 0.154 m in I.D. The secondary air injection nozzles are installed tangentially at the bottom of freeboard. The spent activated carbon is used as fuel in this study. The effects of various operating parameters on CO emission are investigated.
The results show that spent activated carbon heating value is about 4700 kcal/kg, and activation energy value is about 300 kJ/mol. Activation energy decreases as temperature increases, while particle diameter has less effect on activation energy. This shows the spent activated carbon is combustible. Excess oxygen ratio has little effect on the bed temperature. Bed temperature increases and CO emission decreases as stoichiometric oxygen ratio in the bed increases. With higher staging degree air, the lower bed temperature and the higher CO emission. Bed zone combustion proportion increases as stoichiometric oxygen ratio in the bed increases. Bed zone combustion proportion decreases as staging degree air and excess oxygen ratio increases. The stoichiometric oxygen ratio in the bed zone has the greatest impact on combustion proportion.
Generally speaking, the optimal operating condition is 1.08 air flow ratio and 90% stoichiometric oxygen ratio in the bed zone. Under these conditions, as the bed temperature reach 950℃, CO emission reaches a minimum.

並列關鍵字

spent activated carbon ； fluidized bed

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