鄭福田臺灣大學：環境工程學研究所余奕賢Yu, Yi-HsienYi-HsienYu2007-11-292018-06-282007-11-292018-06-282007http://ntur.lib.ntu.edu.tw//handle/246246/62816機車為我國廣為應用之交通工具，然而以往移動源研究對象以汽車為多，機車相關研究十分有限。以往探討三元觸媒轉化器劣化機制 之研究，亦多侷限以汽車為對象。有鑑於此，本研究利用配製模擬廢氣及實驗室加速劣化程序，檢討操作溫度、操作時間及廢氣含氧量對三元觸媒轉化器之影響。本研究利用排氣分析儀配製模擬廢氣通入觸媒中並加以高溫進行劣化程序，再將經劣化後之觸媒樣品，進行特性分析及相關檢討。 觸媒因高溫操作導致熱劣化之機制主要分為載體燒結、活性金屬 燒結及具有活性之結晶因高溫轉變成不具活性。由比較面積分析儀、X光粉末繞射儀、掃瞄式電子顯微鏡—能量分散光譜儀分析結果顯示：在機車操作溫度範圍內，主要熱劣化機制為載體燒結，不論在何種劣化條件下，觸媒之比表面積及孔徑分佈隨劣化溫度提高而往低比表面積及大孔徑分佈方向成長。 在不同劣化條件劣化之觸媒，其起燃溫度曲線呈現不同特性的改變，經5 小時劣化之觸媒活性測試結果與其他條件劣化之觸媒呈趨勢不規則之變化。經當量點及氧化性劣化之觸媒活性測試結果相似，而經還原性劣化之觸媒，活性指標T75 優於其餘二者。溫度與廢氣含氧量對觸媒熱劣化影響較劣化時間顯著。在本研究設定之劣化條件範圍內，本研究建構之模式可合理推估觸媒經長時間操作後之比表面積變化情形。Motorcycles constitute important parts of air pollution emission in Taiwan. However, only limited studies were focused on the deactivation mechanisms of three-way catalyst converters used in motorcycles. Furthermore, the performance of deactivated catalyst converters on motorcycles has not been extensively studied. In this study, thermal aging of the catalyst is simulated in laboratory scale. Based on results of several surface characterization techniques, the effects of aging test exhaust, temperature, and time were examined. Thermal deactivation mechanism is a combination of several aging phenomena, including sintering of active phase, the collapse in surface area and the thermal deactivation of solid phase. According to the measurement results of specific surface area, XRPD, SEM-EDS, the main mechanism of thermal deactivation is deduced as the collapse in surface area. For all thermal aging operating modes studied, the temperature increase reduced the specific surface area and increased the pore size. For all thermal aging operating modes studied, light-off curves of aged catalysts were different. The activity test results of 5 hours aged catalysts were differ from others. The results of activity test of during stochiometric and oxidative aging were similar, and the activity indicator, T75 of during reductive aging catalysts, was lower than the others. The aging temperature and composition of test exhaust are more effective than aging time. The constructed model has good performance on predictions within the thermal aging operating range studied.第一章 前言·························································································· 1 1.1 研究緣起························································································· 1 1.2 研究目標························································································ 2 第二章 文獻回顧·················································································· 3 2.1 機動車輛排氣特性及貢獻····························································· 3 2.1.1 台灣機車現況分析·································································· 3 2.1.2 機動車輛排放特性·································································· 3 2.1.3 移動源廢氣排放成因與對人體健康危害······························ 6 2.1.4 機動車輛排氣特性影響因子·················································· 8 2.1.5 我國機車排氣管制措施························································ 10 2.2 三元觸媒轉化器··········································································· 14 2.2.1 活性金屬················································································ 15 2.2.2 基材························································································ 18 2.2.3 載體························································································ 19 2.2.4 促進劑···················································································· 20 2.3 觸媒熱劣化················································································· 22 2.3.1 熱劣化機制············································································ 22 2.3.2 熱劣化影響因子···································································· 24 2.3.3 加速劣化試驗方法································································ 25 2.4 三元觸媒其他劣化機制······························································· 26 2.4.1 化學性劣化—毒化································································ 26 2.4.2 物理性劣化—阻塞、固相反應與機械磨損························ 27 2.5 觸媒劣化預測模式之探討··························································· 28 第三章 研究方法················································································ 32 3.1 研究規劃······················································································ 32 3.2 試驗參數設定·············································································· 36 3.3 機車使用觸媒熱劣化方法··························································· 40 3.3.1 熱劣化設備介紹···································································· 41 3.3.2 熱劣化程序············································································ 41 3.4 三元觸媒特性分析······································································· 42 3.4.1 表面特性分析儀器及基本原理············································· 42 3.4.2 活性測試設備········································································ 43 3.4.3 活性測試分析程序································································ 45 第四章 結果與討論············································································ 46 4.1 熱劣化對觸媒表面特性之影響··················································· 46 4.1.1 熱劣化對觸媒比表面積之影響············································ 46 4.1.2 熱劣化對觸媒孔徑之影響·················································· 54 4.2 熱劣化引起之固相反應······························································· 58 4.3 熱劣化對觸媒活性之影響························································· 72 4.3.1 活性測試前置試驗······························································ 72 4.3.2 經劣化後之觸媒活性測試····················································· 81 4.4 觸媒比表面積燒結動力模式······················································· 92 4.4.1 燒結動力模式建構································································ 92 4.4.2 經驗模式適用性探討···························································· 98 第五章 結論與建議·········································································· 104 5.1 結論···························································································· 104 5.2 建議···························································································· 106 參考文獻 ···························································································· 107 附 錄 ···························································································· 112 附錄一 儀器分析原理···································································· 113 附錄二 觸媒孔徑分佈圖································································ 119 附錄三 觸媒SEM-EDS 圖譜························································· 122 附錄四 劣化預測模式模擬結果···················································· 14915912775 bytesapplication/pdfen-US三元觸媒轉化器實驗室加速劣化程序熱劣化活性測試起燃溫度曲線熱劣化預測模式three-way catalystlaboratory scale agingthermal deactivationactivity testlight-off curvepredictive modelthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/62816/1/ntu-96-R94541116-1.pdf