| 摘要: | 根據國際能源總署（International Energy Agency，IEA）2011年的統計資料，目前生質能為全球第四大能源，僅次於石油、煤及天然氣，供應了全球約19%的初級能源需求，同時也是目前最廣泛使用的再生能源，約占世界所有再生能源應用的80%。
生質燃料是一種從可再生生物資源，例如生質物，已處理城市廢棄物以及工業垃圾所製造的燃料。生質燃料被廣泛的分類為初級生質燃料與次級生質燃料。本研究以稻殼之生質物為原料，並由流體化條件、液態產率及熱裂解條件與化學分析進行相關研究與探討。
首先，影響最小流體化速度的因素主要有：顆粒直徑、流體黏度等；當載氣流速在0.35m/s (2.33umf)時，平均生質油產率約在20wt%左右，優於其他流速，此時流體化床狀態較佳，使得生質原料裂解效果較好，生質油pH值酸性較弱，酸性物質不易與生質油本身發生二次反應，化學性質安定。溫度對於流體化床壓降的影響不大，同一粒徑的壓降值幾乎相同；當床質尺寸為0.40mm (粒徑比為5.15)時，生質油產率表現最佳(32.18wt%)，流體化程度較完整，碳轉化率最高，生質油pH值酸性較弱，不易發生二次反應，性質安定，元素種類含量，以C、H、O三元素佔大多數，其中碳元素含量最高(約20wt%)，氫元素則在10-15wt%，氮元素與硫元素極低，其餘為氧元素。
第二，在反應溫度500℃時，生質油產率較高 (23wt%-32wt%)，而焦炭與合成氣則隨之下降，HHV表現較佳 (7254.1kcal/kg)，pH值酸性較弱，生質油裂解及轉換效率較佳，反應較完全。另因升溫模式的TGA分析模型已有研究者完成，且等溫模式到達穩態溫度所需的時間較短，反應條件較穩定，故本研究使用模式為等溫模式TGA測定原料之熱重損失，觀測原料裂解之特性，並利用等溫模式計算其裂解反應動力參數；熱裂解後生質油化合物的面積濃度含量較明顯的為：Acetic anhydride(乙酸酐)、1,2-benzenediol(鄰苯二酚)、2-methylphenol(2-甲基苯酚)、phenol(苯酚)。
最後，由相關係數判斷，在粒徑等於0.1、0.4、0.8mm時，流體化壓降對生質油產率為負相關，壓降越小(越接近0.30m/s，2umf)，生質油產率越大，可見最小起泡流體化速度umb (實際操作氣速)相當接近0.30m/s (2umf)；液態產物中，甲基環戊烯醇酮的表現極突出，在碳元素含量、生質油HHV、生質油pH值變化均呈正相關；而乙酸酐、甲苯則在碳元素含量、碳轉化率、生質油HHV變化為負相關；對苯甲酚(4-methylphenol)在碳轉化率呈高度正相關。
;The research can be discussed in two aspects, including fluidizing condition-liquid yield and pyrolysis condition-chemical analysis.
Firstly, the main factor that affects minimum fluidizing velocity (umf) is particle size. When gas velocity falls on 2.33 umf, average oil yield is about 20wt.% which is better than other values, and the pH value is higher, which means bio-oil is hard to second-react with acidic matters in it. Temperature doesn’t have many things to do with fluidizing pressure drop as the value of each size keeps the same; When particle size falls on 0.40mm, there is the best yield of all, 32.18 wt.%. And carbon conversion rate is also higher as acidity is weaker. C, H, O three elements take the majority in bio-oil. For C, is about 20wt.%, for H, is about 10-15wt.%, for the rest part is O as N and S are very few.
Secondly, at 500℃, there are higher oil-yield of 23wt%-32wt%, and so as HHV, the best one is 7254.1kcal/kg. And acidity is weaker while conversion rate is better. For the reason that TGA analysis models of biomass in heating mode have been set up by some researchers while isothermal mode haven’t and needs shorter time to reach steady temperature, this research use isothermal mode to test the thermal-gravimetric loss of biomass observe the properties of pyrolysis, and calculate the pyrolysis dynamic parameters. The chemicals that have apparent area concentration in bio-oil are Acetic anhydride, 1,2-benzenediol, 2-methylphenol and phenol.
Finally, consider those correlation coefficients, the fluidizing pressure drops are negatively related to oil yields. When pressure drops get smaller, closer to 2 umf, the oil yields get higher, which means that the minimum bubbling velocity, umb, is quite close to 2umf ; In chemicals contained in the oil, 2-hydroxyl-3-methyl-2-cyclopenten-1-one is dominant in carbon content, HHV and pH value, and is positively related to them; Meanwhile, acetic anhydride and toluene are negatively related to carbon content, HHV, carbon conversion rate; 4-methylphenol is highly positively related to carbon conversion rate. |
