- 學位論文
甲醇快速催化燃燒器溫度分佈之控制
Control of Temperature Profile for a Rapid Catalytic Methanol Combustor
摘要
本研究將Pt/BN/γ-Al2O3觸媒及空白觸媒(γ-Al2O3載體)混合後填充於不銹鋼管中，並在室溫通入甲醇及空氣使之快速催化燃燒，以探討填充觸媒密度、空間速度及過量空氣對甲醇快速催化燃燒器中溫度分佈之影響，並探討如何控制上述三個因素，使整個燃燒器之溫度分佈落在300℃到500℃之間。實驗中利用21支熱電偶、LabVIEW資料擷取軟體及相關硬體以記錄燃燒器溫度分佈之快速變化。在溫度變化較大區域，每5mm量測並記錄一點溫度，溫度變化較小之區域，則每20mm量測並記錄一點溫度，至於溫度之擷取頻率則為每秒鐘1點。 實驗結果顯示：甲醇催化燃燒在10分鐘內便會啟動，且溫度達到500℃以上；燃燒器最高溫度及最大溫差，隨WHSV增大而增大；觸媒密度降低，最高溫度亦降低；隨著過量空氣的增加，入口溫度及最高溫度皆下降，但出口溫度則提高。綜合言之，在觸媒密度為0.401 g/cm3，WHSV為0.8 h-1及過量空氣為300 %時，我們可以控制燃燒器之溫度分佈在295~497℃之間。在多次相同實驗中，實驗數據之再現性良好，顯示本研究之數據為可信。
關鍵字
甲醇快速催化並列摘要
In this study, Pt/BN/γ-Al2O3 catalyst was mixed with blank catalyst (γ-Al2O3 support) and packed in a stainless steel tube for methanol combustion starting from room temperature. The effects of catalyst density, space velocity and excess air on temperature profiles along the catalytic methanol combustor have been studied. It was also investigated to control the above mentioned factors such that the temperature of the whole combustor could be controlled between 300℃ and 500℃. Twenty one thermocouples, LabVIEW data acquisition software and related hardware were used in the experiment to record the rapid change of the temperature profile in the reactor. One thermocouple was used every 5 mm for area with large temperature gradient, and every 20 mm for area with small temperature gradient. The frequency of temperature acquisition was one per second. The Experimental results show that the catalytic combustion of methanol starts within 10 min, and the temperature can be over 500℃. The maximum temperature and maximum temperature difference in the combustor increase with increasing WHSV. Decreasing density of catalyst decreases the maximum temperature. Increasing excess air decreases the inlet temperature and the maximum temperature, however, it increases the outlet temperature. In summary, when catalyst density is 0.401 g/cm3, WHSV is 0.8 h-1 and excess air is 300%, the temperature profile of the combustor can be controlled between 295℃ and 497℃. Repeated experimental runs give similar results, indicating the reproducibility of the experiment is good.