| 摘要: | 柴油引擎廢氣對人類健康與環境衝擊有重要的影響，特別是廢氣中的懸浮微粒。本研究探討柴油引擎發電機使用不同生質柴油配方所排放微粒水溶性離子特性，此外並利用不同油品或加裝濾煙器探討對重型柴油引擎尾氣排放微粒水溶性離子組成的影響。
以不同比例之黃豆生質柴油、95%含水乙醇、丁醇添加於市售柴油中的柴油發電機廢氣微粒中，零負載(0W)時調整柴油配方加入生質柴油有助減少微粒質量的排放強度，但在1600W及3200W的中高度負載其微粒排放係數並未明確減量趨勢，其總水溶性離子排放係數，在相同負載下，生質油與市售柴油排放作比較，零負載減量47.8~67.0%，高負載減量47.3~58.5%，中負載並未有明確減量趨勢。在相同油品與負載下，柴油發電機廢氣的微粒水溶性離子排放係數大小順序為總陰離子、總陽離子、總羧酸，其中單元羧酸類－甲酸會隨市售柴油的比例下降，排放係數降低，其他物種並無此一趨勢，在各種油品配方及負載條件下，甲酸與乙酸都較市售柴油的排放係數低，分別減量19.3~85.1%與0.2~74.0%。在硫酸鹽與硝酸鹽的排放係數，在0W與3200W較市售柴油具分別減量9.0~92.2%與23.5~71.5%。此外廢氣微粒並未出現丙二酸，顯示大氣氣膠丙二酸主要來源並非柴油發電機而是來自大氣光化產物。柴油發電機廢氣微粒的oxalic/sulfate ratio，在0W 與1600W添加生質柴油的油品廢氣微粒之值介於0.07~0.17，較一般大氣氣膠的0.045與0.05高，在acetic/formic ratio隨著甲酸排放係數的下降，其值也跟著上升，比值介於8.7~57之間，遠大於大氣氣膠之值。
重型柴油引擎以市售超級柴油B1(S50)為基準，進行B1(S50)加裝氧化觸媒濾煙器(B1(S50)+DPF)、B1(S50)加裝氧化觸媒(B1(S50)+DOC) 與低硫柴油B1(S10)等不同控制技術之測試。動力計測試條件為美國暫態循環、穩態惰轉與穩態低負載。四種測試條件下，柴油引擎尾氣PM2.5總離子排放係數依序為市售超級柴油B1(S50)的6.68 mg/bhp-h、使用B1(S10)柴油的6.67 mg/bhp-h、裝設DOC之B1(S50)柴油的6.40 mg/bhp-h 、裝設DPF之B1(S50)柴油的2.32 mg/bhp-h。裝設DOC對引擎尾氣PM2.5整體離子物種減量4.2%，DPF減量65.2%，使用B1(S10)對引擎尾氣PM2.5整體離子物種減量0.2%，其中對NO3-及SO42-排放均有減量助益，尤其SO42-減量34.7%，但B1(S50)+DOC因觸媒轉化之故，促使尾氣微粒的NO3-及SO42-生成反而較B1(S50)為高，另外尾氣所排放之oxalic acid卻是以B1(S50)的生質柴油排放係數最小，其他控制技術並無減量。各種控制技術尾氣微粒的總水溶性離子減量主要來自陽離子的減量。B1(S50)+DPF在PM2.5的總水溶性離子為B1(S50)+ DOC的36.3%，顯示DPF的濾煙效果較DOC為佳。此外，B1(S50)柴油引擎在惰轉時所排放之微粒水溶性離子物種排放係數為低負載之10.7~41.2倍，顯示柴油引擎維持怠速運轉，將產生高數值的PM2.5微粒水溶性離子物種排放係數。
Diesel engine emissions on human health and environmental impact has important implications, particularly in suspended particles of emissions. This study investigated the diesel engine generator using a different biodiesel formula for water-soluble ions characteristics of particulate emissions, in addition to using different oils or retrofitting of particulate traps on heavy-duty diesel engine discuss water-soluble ions composed of exhaust particles.
Particles of diesel generators exhaust with soy biodiesel, hydrous ethanol(95%), butanol of different ratios added to commercial diesel, idle (0W) to adjust the formula by adding diesel biodiesel quality will help reduce particulate emissions intensity, However, 1600W and 3200W of high loading particulate emission factor is not clear reduction trend, the total emission coefficient of water-soluble ions in the same load, biodiesel compared with commercial diesel emission, idle reduction of 47.8 ~ 67.0% high loading reduction of 47.3 ~ 58.5%, Intermediate loading did not have a clear reduction trend. In the same formula fuel and load, the diesel generator exhaust particulate emission factor of water-soluble ions in the order of the total anions, total cations, total carboxylic acids, of which unit carboxylic acid－formic acid would decline with the proportion of commercial diesel fuel reduce, other species emission factor do not have this trend, in various oil formulations and load conditions, formic acid and acetic acid are relatively lower than commercial diesel, emission factors were reduction 19.3~85.1% and 0.2~74.0%. Sulfate and nitrate in the emission factors, the 0W and 3200W respectively, compared with commercial diesel fuel with a reduction of 9.0~92.2% and 23.5~71.5%. In addition, particulate emissions does not appear malonic acid, show diesel generators is not the main source of aerosol malonic acid but from atmospheric photochemical reactions. Diesel generator exhaust particulate oxalic/sulfate ratio, in the 0W and 1600W oil add biodiesel, the value of exhaust particles is between 0.07~0.17, higher than normal atmospheric aerosol of 0.045 and 0.05, in the acetic / formic ratio as formic acid emission factors of decline, the value also followed up, the ratio ranged between 8.7~57, much larger than the value of atmospheric aerosol.
The heavy-duty diesel engine was operated with a number of control technologies, including diesel particulate filter (B1(S50)+DPF), diesel oxidation catalyst (B1(S50)+DOC), low sulfur (B1(S50)) and ultra-low sulfur diesel (B1(S10)), in which the baseline is B1(S50) with no after-treatment. The simulated driving conditions include US FTP trancient cycle, idle, and low-load stready-state cruise. Four test conditions, the total water-soluble ions’ emission factor of PM2.5 at the diesel engine exhaust, order of commercial super diesel B1(S50) is 6.68 mg/bhp-h, using the B1(S10) diesel is 6.67 mg/bhp-h, loaded set DOC of B1(S50) diesel is 6.40 mg/bhp-h, the installation of DPF of B1(S50) diesel is 2.32 mg/bhp-h. DOC installed on the engine exhaust PM2.5 ionic species in the overall reduction of 4.2%, DPF reduction of 65.2%, using the B1(S10) on the engine exhaust PM2.5 ionic species in the overall reduction of 0.2%, on the NO3- and SO42- emission reductions are useful, in particular SO42- reduction 34.7%, but B1(S50)+DOC due to catalytic converter, therefore, to facilitate exhaust particulate NO3- and SO42- generated rather than the B1(S50) is higher, while the minimum oxalic acid emission factor of exhaust emissions is B1(S50), a biodiesel, there is no reduction of other control technologies. All kinds of exhaust particulate control technology reducing the total water-soluble ions mainly from the reduction of cations. Total water-soluble ions of B1(S50)+DPF in PM2.5 as B1(S50)+DOC 36.3%, indicating that smoke effect DPF filter is better than the DOC. In addition, the discharge of particulate emission factor of the water-soluble ion species when B1(S50) diesel engine idle for the low load of 10.7~41.2 times, indicating that diesel engine to maintain idle, will produce high values of PM2.5 particles water-soluble ions Species emission factor. |
