Persistent organic pollutants from a diesel engine generator fueled by waste cooking oil-based biodiesel blended with butanol and acetone

• Main Authors: Jheng, Bo-Cheng, 鄭博丞
• Other Authors: Chen, Shui-Jen
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/6w442y

碩士 === 國立屏東科技大學 === 環境工程與科學系所 === 105 === This study focuses on the effects on the emissions of persistent organic pollutants (POPs), including polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs), and polybrominated diphenyl ethers (PBDEs) by using multi-components waste cooking oil-based biodiesel blends. The base fuel was traditional diesel (abbreviated as D), while the additives included various fractions of butanol (B), 5% water-containing butanol (B’), acetone (A), 5% water-containing butanol (A’), isopropyl alcohol (I), and waste cooking oil-based biodiesel (W). The fuel blends, B30, B'30, A3, A'3, B30A3, and B'30A'3, were tested at 1.5 and 3.0 kW engine output power to analyze all the aforementioned POPs collected in the engine exhaust. The emission concentrations of four POPs were in the order PBDEs ≫ PBDD/Fs > PCBs > PCDD/Fs, despite using different blending fuels at both engine loads. PBDE had the highest level among the POPs, being equal to 2–3 times to the others. On the other hand, the order of emitted toxicity followed PCDD/Fs > PCBs ≈ PBDD/Fs, while the toxicity of PCDD/F emissions were about 10 times higher than those of PCBs and PBDD/Fs. Among the dioxin compounds, the emissions of PCDDs represented 46–73% (57% in average) and 50–72% (59% in average) of total PCDD/F mass and toxicity concentrations, respectively, and were significantly higher than those of PCDFs. Specifically, the highly chlorinated PCDD/Fs (OCDD, OCDF, 1,2,3,4,6,7,8-HpCDD, and 1,2,3,4,6,7,8-HpCDF) contributed 83% of total PCDD/Fs mass concentration. However, the low-chlorinated PCDD/F congeners played important roles in the toxicity emissions; 2,3,7,8-TeCDD and 1,2,3,7,8-PeCDD dominated the B30A3 and B'30A'3 emissions and 1,2,3,7,8-PeCDD and 2,3,4,7,8-PeCDF were dominant by using the other fuels. The Non-o-PCB contributed almost all toxicity (~100%) of 14 dioxin-like-PCBs, even though its contribution in mass was only 9–32% (16% in average) among the congeners. Specifically, PCB-118, -105 and -77 had the three higher mass contents among the PCB congeners, while PCB-126 dominated 90% of PCB toxicity emissions. A similar case was found in PBDFs, which exhibited ~100% toxicity of PBDD/Fs. Additionally, the mass emissions of PBDEs were mostly provided by deca-BDEs (47.0–90.5%, 82.4% in average), while nona-BDEs and tri- to octa-BDEs were only contributed 10% and 8%, respectively. The reductions of POPs were observed by using various diesel blends in comparison to using W20. The mass reduction amounts (%) of four POPs were in the order PCDD/Fs > PCBs ≈ PBDD/Fs > PBDEs, and the order of toxicity reductions was PCDD/Fs > PCBs > PBDD/Fs. For PCDD/Fs, the mass and toxicity levels of 17 congeners were reduced by using various additives, when the OCDD and OCDF mass emissions showed the most significant improvement. The highest reduction in toxicity was found for 2,3,7,8-TeCDD at 1.5 kW and for 1,2,3,7,8-PeCDD at 3.0 kW. For dioxin-like PCBs, the greatest decreases of mass and toxicities were both observed from PCB-126 (82.1% in mass and 80.0% in toxicity). Consequently, the additive of butanol and acetone, including pure and hydrous mixtures, could further effectively reduce the POP emissions from W20.