- 學位論文
銻化鉍低溫熱電模組於下抽式氣化爐廢熱回收之應用
The Waste Heat Recovery Application of Low-Temperature Bi2Te3 Thermoelectric Modulus on Downdraft Gasifier
摘要
近年來由於東日本大地震的影響，加以核四的各項不安全因素，使得反核的聲浪日漸高漲，同時暴露出能源短缺的問題。氣化技術做為高端的技術，已漸漸成為獲取能源一個不錯的選擇。此外，由於材料科技的興起與製程的改進，在熱電材料這一塊領域已有相當廣泛的應用。 本研究主要探討銻化鉍低溫熱電材料於下抽式氣化爐做廢熱回收的情形，實驗總共分為三部分：首先量測熱電模組之各項特性參數與性質，其次研究稻殼和柳杉在不同比例的混合情形下於下抽式氣化爐氣化產氣的情形，最後將熱電模組貼附於氣化爐的觸媒管壁上做廢熱回收的探討。 實驗結果發現，熱電模組的開路電壓高溫端溫度升高、低溫端入水溫度降低而升高，且在高溫端溫度500℃，低溫端入水溫度5℃時有最大值為59.85V，同時輸出功率有最大值為33.15W；轉換效率和ZT值最大分別為3.6%和0.186。在氣化方面H2、CO和CH4的最大含量為17.82 vol.%、24.73 vol.%及3.72 vol.%；產氣熱值與冷煤氣效率為5.75MJ/m3及64.55%。廢熱回收方面熱電模組產生之最大功率、電能輸出及能量密度分別為2.633W、16177.68J及86.61W/m2。
並列摘要
Due to influences of east Japan earthquakes and unsafe factors of 4th nuclear power plant, opposition to nuclear electricity generation has snowballed in recent years. As an outstanding technique, gasification technology has become a better choice to generate energy. Besides, as material technology grows and manufacturing process improved, there has been a wide variety applications in the field of thermoelectric materials. This study aims at waste heat recovery by low-temperature Bismuth-Telluride thermoelectric material on downdraft gasifier. The experiment was devided into 3 parts. First, measuring parameters and properties of thermoelectric modulus. Second, investigating syngas produced from downdraft gasifier under different blending ratio of rice husk and Japanese cedar. At last, combining thermoelectric modulus with catalyst tube of gasification system to investigate waste heat recovery. The result has shown that open –circuit voltage rise when hot side temperature increase and inlet temperature of cold side decrease. There are maximum value 59.85V and maximum power output 33.15W with hot side temperature 500℃ and cold side water inlet temperature 5℃; the optimum value of conversion efficiency and the figure of merit are 3.6% and 0.186, respectively. The maximum amount of H2, CO and CH4 are 17.82 vol.%, 24.73 vol.% and3.72 vol.%, while high heating value and cold gas efficiency have optimum value of 5.75MJ/m3 and 64.55%. The maximum value of power, electric energy output and power density of waste heat recovery are 2.633W, 16177.68J and 86.61W/m2.