生質柴油發電機排放PM及PM上碳與PAHs特性之研究

Characteristics of PM and particle-bound carbons, and PAHs emitted from a biodiesel-fueled generator

蔡仁雄(Jen-Hsiung Tsai)

指導教授 ： 陳瑞仁 ； 黃國林

國立屏東科技大學/工學院/環境工程與科學系所/博士(2011年)

https://doi.org/10.6346/NPUST.2011.00019

摘要

近年來由於工業與都市快速成長，導致能源消耗不斷增加；加上原油的存量有限與價格不穩定，及對環境的考量，可再生能源之需求更為迫切，而生質柴油是種相當具應用潛力之再生能源。且至目前以生質柴油為柴油引擎之替代燃料已受廣泛地研究與應用，然將生質柴油運用於柴油引擎發電機之研究至今仍甚少。生質柴油是以動、植物油酯與醇類（甲醇或乙醇）轉酯化反應而來，常見以大豆油、油菜籽油、向日葵油及棕櫚油等可食用油作為生質柴油之製作原料，有可能會引起糧食短缺之爭議；因此，尋找非食用油來替代可食用油以轉製成生質柴油已是必然，其中回收廢食用油應為可行之法。因此本研究分別以純石化柴油(D100)及不同掺配比黃豆油生質柴油(soybean biodiesel) [ S10 (10 vol% soybean biodiesel)、S20、S50 ] 與廢食用油生質柴油(waste-edible-oil biodiesel) [ W10 (10 vol% waste-edible-oil biodiesel)、W20、W30、W50 ] 在穩定發電狀態下，分別探討柴油發電機排放粒狀物（particulate matter，PM）、PM上碳成分、總PAHs及其毒性當量(BaPeq)之排放特性。

研究結果顯示：與傳統石化柴油相較，使用黃豆油生質柴油對柴油引擎發電機PM、碳成分、Total-PAHs及其毒性當量（BaPeq）亦均有明顯的減量效果，尤以S20時(掺配比20%)對柴油引擎發電機排放污染物之減量效果最佳 [ PM可減少4~23%；碳成分(TC)可減少9~29%；Total-PAHs可減少12~46%；毒性當量可降低23~35% ]；在能源效率與比耗油率（Brake Specific Fuel Consumption, BSFC）之試驗結果發現，無論在何種負載下，黃豆油生質柴油發電機之BSFC值均與掺配比成正相關(即較耗油)。而柴油引擎發電機使用廢食用油生質柴油亦可有效降低發電機尾氣中污染物排放，其中亦以20%掺配比(即W20)時污染之減量效果較佳 [ PM可減少17~38%；碳成分(TC)可減少32~37%；Total-PAHs可減少16~32%；毒性當量可降低4~54% ]；此外，使用廢食用油生質柴油時亦會稍增加柴油發電機之BSFC (約增加1~11%)。此結果顯示：無論廢食用油生質柴油或黃豆油生質柴油，除可作為石化柴油之替代燃料外，柴油引擎發電機使用生質柴油時亦可大大地降低其排氣中PM及PM上碳成分與PAHs。

關鍵字

廢食用油生質柴油 ； 黃豆油生質柴油 ； 多環芳香烴化合物 ； 碳成分 ； 柴油發電機

並列摘要

International oil price has been going up in recent years because of decrease of crude oil reserves. Therefore many countries have devoted to the research and development of alternative energies. Bio-diesel is one of the alternative energies that have been extensively discussed and studied. Although many studies about the usage of bio-diesels have been conducted, very few researches were conducted to investigate the use of bio-diesels in electricity generators. After generating biodiesel by a transesterification reaction produced by adding alcohol to vegetable oil or animal fat, biodiesel can be catalyzed by acid or alkali. Biodiesel is typically transformed from edible oils such as soybean oil, rapeseed oil, sunflower oil, and palm oil. Nevertheless, compared to fresh edible oil, recycled waste edible oil is a better raw material for biodiesel production given ongoing agricultural land shortages. In this study, tested fuels were prepared by mixing pure diesel oil (D100) with different percentage of soybean biodiesel or waste-edible-oil biodiesel, such as S10 (10 vol% soybean biodiesel+ 90 vol% diesel), S20, S50, W10 (10 vol% waste-edible-oil biodiesel + 90 vol% diesel), W20, W30 and W50. Different fuels were tested as the engine generated stable electricity to investigate the emission characteristics of particulate matter (PM), particle-bound total carbons (TC, including organic/elemental carbons), Total-PAHs and the Total-Toxicity-Equivalency (Total-BaPeq).

The results showed that among the tested diesel blends (D100, S10 (10 vol% soy-biodiesel), S20, and S50), S20 exhibited the lowest PM emission concentration despite the loads (except the 5 kW case), whereas S10 displayed lower PM emission factors when operating at 0 and 10 kW than the other fuel blends. The emission concentrations or factors of EC, OC, and TC were the lowest when S10 or S20 was used regardless of the loading. Under all tested loads, the average concentrations of Total-PAHs emitted from the generator using the S10 and S20 were lower (by 38% and 28%, respectively) than those using pure petroleum diesel fuel (D100), while the emission factors of Total-PAHs decreased with an increasing ratio of biodiesel to premium diesel. With an increasing loading, although the brake specific fuel consumption decreased, the energy efficiency increased despite the bio/petroleum diesel ratio. When using waste-edible-oil biodiesel as an alternative fuel for diesel generators, on average, the PM emission factors of all blends was 30.5% (range, 13.7–52.3%) lower than that of D100 under the tested loads. Substituting pure fossil diesel oil with varying percentages of waste-edible-oil biodiesel reduced emissions of particle-bound TC and EC. The W20 blend had the lowest particle-bound OC emissions. Notably, W10, W20, and W30 also had lower Total-PAH emissions and lower total equivalent toxicity (Total-BaPeq) compared to D100. Compared with traditional petroleum diesel oil, 20% mixture ratios (i.e. S20 and W20) had the best effect in reducing emissions of PM (4–23% and 17–38%, respectively), TC (9–29% and 32–37%, respectively), Total-PAHs (12–46% and 16–32%, respectively), and Total-BaPeq (23–35% and 4–11%, respectively). Additionally, the brake-specific fuel consumption of the generator correlated positively with the ratio of waste-edible-oil biodiesel to pure fossil diesel (increased by 1.04–11.2%). However, generator energy efficiency correlated negatively with the ratio of waste-edible-oil biodiesel to pure fossil diesel. Therefore, either the soybean biodiesel or waste-edible-oil biodiesel may be used as an alternative fuel for diesel generators and reduce the emissions of PM, carbons, and PAHs.

並列關鍵字

Waste-edible-oil biodiesel ； Soybean biodiesel ； Polycyclic aromatic hydrocarbons ； Carbons component ； Diesel generator

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