下抽式氣化爐之空氣進氣及投料系統改良設計對產氣狀況之影響研究

Abstract

生質是一種重要永續能源，它的主要來源為廢竹木及收成後之農作物根莖與穀殼和水生植物等，使用生質當燃料來發電可減少地球溫室氣體的排放。本實驗之向下氣流式氣化爐可製造出低焦油量之乾淨產氣，適合可作為燃氣引擎與為渦輪機等之燃料。因此，本研究以向下氣流式式氣化爐（高度1000mm與直徑200mm）來探討操作條件對產氣狀況之影響研究。 本氣化爐針對空氣流量、進料方式、上噴空氣、燃料種類、燃料含水量等變因，探討其燃料消耗率、產氣成份與熱值，經由本實驗可得知最佳操作範圍，當燃料供給率之範圍為9.至9.5 Kg/hr時，其最佳空燃比之範圍為2 至2.2之間；此時可輸出最佳之產氣熱值範圍為4.5至4.7 MJ/Nm3，且其產氣率範圍為20-23 Nm3/h。根據歷代爐子的比較結果可以得知,燃料水分進料與進氣控制與爐體保溫對於單位面積燃燒速率與產氣熱値影響很重大。

Biomass is an important renewable energy resource produced from trees, agriculture crops and aduatic plants. Using biomass as fuel for power generation is carbon neutral and helps to lower the emission of global warming gases. Downdraft gasifier is suitable for gas engine and micro turbine due to the fact that its producer gas contains low tar and clean producer gas. Therefore this downdraft gasifier with 1000mm height and 200mm diameter is used in this study to investigate the relations between quality of producer gas and operation conditions. The effect of air flow rate, feeding manner, upper air feeding system, fuel kind and moisture content on the fuel comsuption rate, gas composition and calorific value is presented. The optimum operation of this gasifier is in the range of 9 to 9.5 Kg/h at air to fuel ratio between 2 and 2.2.The best range HHV of producer gas is 4.5 to 4.7 at producer gas flow rate between 20 and 22 Nm3/h. Comprehensive comparison on the performance of gasifier with the previous studies of our laboratory has been performed in this work. Results indicate that the moisture content of fuel, the feeding of fuel and air, as well as the insulation of the gasifier reactor are significant to the fuel conversion rate and producer gas heating value.