- 學位論文
乳化燃料之微爆現象與燃燒性能分析
Experimental Study on Microexplosion and Combustion Characteristics of Emulsified Fuel
摘要
本研究建立了一套可以觀察液滴受熱行為與微爆現象的實驗裝 置。研究中探討之液滴包括未加水之六號重油與不同含水量之乳化 液。其中乳化液分為由十六烷燃料與不同水含量組合成之乳化液以及 由六號重油與不同水含量組合成之乳化液，觀察其在熱環境中受熱產 生的微爆現象和分析相關參數對微爆特性的影響。實驗中藉由熱電偶 量測受熱液滴的溫度變化及利用高速攝影機擷取影像做觀察，可以成 功描述分析液滴的微爆過程與現象。 本研究之重點在於探討不同的環境溫度(Tsur=300℃、400℃和 500℃)和含水量百分比(Cw=0%、10%、12%、20%、30%和40%)及不 同大小液滴直徑(do ≒0.7 mm 及do ≒1 mm)這三個重要參數對微爆 現象、微爆溫度和微爆時間等微爆特性的影響。同時針對低硫乳化燃 料油(Cw=0%和12%)進行工業燃燒模擬設施之實際測試以評估油品之 節能效益。 十六烷/水乳化液滴的微爆現象，依照高速攝影機影像觀察微爆結果顯示，大液滴(do≒1 mm)之微爆時間比小液滴(do ≒0.7 mm)來得較長。不論含水量多寡，微爆時間隨著環境溫度升高而縮短，且微爆溫度隨環境溫度升高而降低。在含水量的影響方面，當含水量愈高時 愈有助於微爆現象的發生。另外，噴發現象會影響微爆時間，一般而 言，乳化液滴在微爆發生前，若有噴發現象發生，則其微爆時間會提 早。 在工業燃燒模擬設施測試方面，低硫乳化燃料油因添加了12%的 水，雖然加熱效果下降約2.7%(整體平均差約35oC)，但NOX 排放量亦 減少約78 ppm(約下降27%)。另外，因20L/h 的供油率裡實際的低硫 燃料油含量只有17.6 L/h，所以節省了2.4 L/h的燃料油，故使用低硫乳化燃料油可達到節省油量及降低污染排放的目的。
並列摘要
An experimental system for observing drop heating and microexplosion was established. The emulsion drops consisted of either No. 6 heavy oil or N-hexadecane with various water contents. The heating process was recorded by a high-speed video camera while the ambient and drop temperature were measured by a thermocouple. Three ambient temperatures, six water contents, and two drop sizes were adopted to investigate the micro-explosion phenomenon. The results showed that the waiting time for the onset of micro-explosion is longer for a larger drop. With the increase of water content, the temperature range for micro-explosion reduced. In addition, micro-explosion time and temperature decreased with increasing ambient temperature. Low-sulfur emulsion fuel was also tested in an industrial furnace simulator facility. Although the heating power reduced about 2.7% due to the water content in the fuel, the fuel flow rate was reduced by 12% .Emissions were significantly improved. NOX was lowered by about 78ppm (27%). Therefore, using low-sulfur emulsion fuel can improve fuel economy and decrease pollutants emissions.