本研究應用熱再循環原理與觸媒燃燒技術，發展一過焓觸媒燃燒器。主要設計概念是以蜂巢式白金觸媒作為燃燒室主體，利用氫氣不需加熱便可與觸媒反應之特性，解決燃燒器的引燃問題，而且使氫燃料在極貧油的情況下仍可穩定進行反應，使燃料利用更有效率。實驗重點針對預混氫氣/空氣燃料於白金蜂巢式觸媒表面催化後所產生之熱流場作研究，使用熱電偶溫度量測系統獲得瑞士捲燃燒器溫度分佈，主要是在瑞士捲燃燒器入口、出口、觸媒段入口與出口處等，將熱電偶埋入至瑞士捲燃燒器流道中，藉由改變燃氣雷諾數（Ref）、當量比（?）及觸媒段長度（Lc）等實驗參數探討其對燃燒器溫度分佈變化之影響，本實驗有助於建立觸媒燃燒與熱再循環之整合技術。同時針對觸媒材料使用之限制，我們定義出此燃燒器最佳化操作區域，以充分掌握燃燒器關鍵操作技術。過焓觸媒燃燒器之實驗結果顯示，氫氣與空氣混合體積濃度比Cvp = 0.27%時仍可穩定產生熱釋放，大幅地延伸傳統貧油可燃極限(氫氣的貧油可燃極限為Cvp = 4%)。有關燃氣雷諾數和停滯時間對觸媒段出口溫度Tc-out之影響如下，在Lc = 3.0 cm與固定?值條件下和Ref ? 380 ~ 630的範圍內，Tc-out將隨 Ref增加而上升，這可能是因為氫氣在觸媒表面擁有極佳的吸附能力和解離能力，在很短的停滯時間內便可以啟動觸媒燃燒反應，所以停滯時間效應對觸媒段出口溫度影響並不明顯。至於燃燒器應用方面，我們串聯多個熱電材料(Bi2Te3)元件，以建構一簡易熱電產生器。初步實驗結果顯示，串聯2個熱電元件可產生約5.2伏特無負載電壓，可輕易讓低功率燈泡發亮和驅動馬達，但目前輸出電壓的穩定度仍然不佳，我們將繼續提升系統穩定度，以邁向最佳化設計。 This study applies heat recirculation and catalytic combustion technologies to develop an excess enthalpy catalytic burner. We use honeycomb Pt catalyst as the main body of the combustor, so that hydrogen gas can react with Pt catalyst even at room temperature without extra ignition energy. This avoids several ignition problems and makes the use of fuel more efficient. Many K-type thermocouples are inserted into the channels of the Swiss-roll burner to measure the temperature distributions at various different experimental parameters, such as the flow Reynolds number (Ref = VfD/?) ranging from 380 to 630, fuel/air mixture by volume (Cvp) ranging from 0.27% to 8% and the length of the honeycomb catalyst (Lc) ranging from 0.5 cm to 3.0 cm, where Vf is the gas velocity, D is the width of the channel, and ? is the kinematic viscosity of reactants. From these temperature measurements, the integration of heat recirculation and catalytic combustion technologies can be achieved. The optimum operating region in using the Swiss-roll catalytic burner is identified. The results indicate that our burner can be operated at extra lean condition with only Cvp = 0.27%, which is much less than the common lean flammability limit of H2/air mixtures (Cvp = 4%). The effect of Ref on Tc-out (outside temperature of the honeycomb catalyst) at fixed Cvp and Lc = 3.0 cm is discussed. For the practical use, we apply Bismuth Telluride thermoelectric (TE) chips in series to construct a small TE power generator, where the TE materials are purchased from Hi-Z technology company with model HZ-2 (~3 cm x 3 cm area). The preliminary results show that the Swiss-roll catalytic TE generator can easily produce about 0.46 watts if only two TE chips in series are used. Areas for future study and further improvement are discussed, such as the stability of the power output and the optimal operating conditions.
