| 摘要註: |
本研究主要以二階段流體化氣化爐做為討論,探討氣化過程中產氣組成與重金屬之流佈,並以添加劑(活性碳、氧化鈣、石英砂、鍛燒煤、沸石)做為吸附重金屬的討論對象。結果顯示當第一階段操作溫度由700{212B68}增加至900℃時,產氣效率相對提升,但對重金屬底渣截留效果較差且增加逸散濃度,ER值由0.2提升至0.4時有較高之產氫量,但總熱值與總產氣量降低,重金屬則在較高ER值時,底渣截留率較佳,S/B比由0提升至0.5,雖提高甲烷-水氣反應,但熱值與總產氣量亦相對減少,而S/B比對重金屬則較無影響。因此本研究以兩階段操作溫度同為900℃,ER為0.3、S/B為0.5的參數條件做為最佳產氫操作設計。另外添加劑粒徑的研究結果顯示,當添加劑粒徑為0.545 mm時,添加CaO產生之合成氣有較高熱值,Zeolite與SiO2則有較高產氫量。粒徑為0.775 mm時,AC有較高產氫量與熱值。對重金屬的吸附結果顯示比表面積較大對重金屬吸附量較佳,較大粒徑下 (平均粒徑0.775 mm) 活性碳對重金屬Cu、Pb、Zn吸附濃度分別為0.24 mg/g、0.15 mg/g、0.11 mg/g,較小粒徑下(0.545 mm)沸石也有較佳的重金屬吸附量,Cu、Pb、Zn吸附濃度分別為0.12 mg/g、0.08 mg/g、0.049 mg/g。因此添加劑對於重金屬吸附效果,以活性碳較佳,沸石與氧化鈣次之。 This research applied the two-stage fluidized gasifier procedure to discuss the composition of syngas and the distribution of heavy metals. Five additives (active carbon, zeolite, calcined cal, calcium oxide, silica sand) were used to adsorb heavy metal during gasification. The results showed that rising temperature from 700℃ to 900℃ at the first stage promotes the efficiency of gasification. Oppositely, the retention rates of heavy metal ash in bottom ash reduced and the concentration of heavy metal in fly ash increased. With Equivalence ratio (ER) rising from 0.2 to 0.4, the productivity of hydrogen increased, but the total yield and total heat value of gas decreased. Although the Steam/Biomass ratio (S/B) increases from 0 to 0.5, that enhance the methane-steam reaction, the total yield and heat value of produced gas reduces. S/B had less effect on distribution of heavy metal. Therefore the best parameter is T= 900℃,ER=0.3,and S/B=0.5. This condition will produce more hydrogen. For additives results, the the syngas had higher heat value with adding CaO but higher productivity of hydrogen added zeolite and SiO2 as the particle size was 0.545 mm. As the particle size was 0.775 mm, AC had higher productivity of hydrogen and heat value. The results of adsorption of heavy metals showed that the high surface area lead to more adsorption efficiency. As a result, the best adsorption efficiency of heavy metal among these additives was active carbon and followed by zeolite and calcium oxide. |