Environ. Sci. Technol. 2008, 42, 3849–3855
Approach for Energy Saving and Pollution Reducing by Fueling Diesel Engines with Emulsified Biosolution/ Biodiesel/Diesel Blends Y U A N - C H U N G L I N , †,‡ W E N - J H Y L E E , §,| HOW-RAN CHAO,⊥ SHU-LI WANG,# TSUI-CHUN TSOU,# G U O - P I N G C H A N G - C H I E N , †,‡ A N D P E R N G - J Y T S A I * ,§,∇ Department of Chemical and Materials Engineering and Super Micro Mass Research & Technology Center, Cheng Shiu University, Kaohsiung County 833, Taiwan, Sustainable Environment Research Center and Department of Environmental Engineering, National Cheng Kung University, Tainan 701, Taiwan, Department of Environmental Science and Engineering, National Pingtung University of Science and Technology, Neipu, Pingtung 912, Taiwan, Division of Environmental Health and Occupational Medicine, National Health Research Institutes, Miaoli 350, Taiwan, and Department of Environmental and Occupational Health, Medical College, National Cheng Kung University, Tainan 704, Taiwan
Received November 23, 2007. Revised manuscript received February 5, 2008. Accepted February 6, 2008.
The developments of both biodiesel and emulsified diesel are being driven by the need for reducing emissions from diesel engines and saving energy. Artificial chemical additives are also being used in diesel engines for increasing their combustion efficiencies. But the effects associated with the use of emulsified additive/biodiesel/diesel blends in diesel engines have never been assessed. In this research, the premium diesel fuel (PDF) was used as the reference fuel. A soy-biodiesel was selected as the test biodiesel. A biosolution made of 96.5 wt % natural organic enzyme-7F (NOE-7F) and 3.5 wt % water (NOE-7F water) was used as the fuel additive. By adding additional 1 vol % of surfactant into the fuel blend, a nanotechnology was used to form emulsified biosolution/soybiodiesel/PDF blends for fueling the diesel engine. We found that the emulsified biosolution/soy-biodiesel/PDF blends did not separate after being kept motionless for 30 days. The above stability suggests that the above combinations are suitable for * Corresponding author phone: +886-6-2088390; fax: +886-62752484; e-mail:
[email protected]. † Department of Chemical and Materials Engineering, Cheng Shiu University. ‡ Super Micro Mass Research & Technology Center, Cheng Shiu University. § Sustainable Environment Research Center, National Cheng Kung University. | Department of Environmental Engineering, National Cheng Kung University. ⊥ Department of Environmental Science and Engineering, National Pingtung University of Science and Technology. # Division of Environmental Health and Occupational Medicine, National Health Research Institutes. ∇ Department of Environmental and Occupational Health, National Cheng Kung University. 10.1021/es702835n CCC: $40.75
Published on Web 04/18/2008
2008 American Chemical Society
diesel engines as alternative fuels. Particularly, we found that the emulsified biosolution/soy-biodiesel/PDF blends did have the advantage in saving energy and reducing the emissions of both particulate matters (PM) and polycyclic aromatic hydrocarbons (PAHs) from diesel engines as compared with PDF, soy-biodiesel/PDF blends, and emulsified soy-biodiesel/ PDF blends. The results obtained from this study will provide useful approaches for reducing the petroleum reliance, pollution, and global warming. However, it should be noted that NOx emissions were not measured in the present study which warrants the need for future investigation.
Introduction The problem associated with the emissions of smoke, PM, sulfur oxide (SOx), PAHs, and odor from the exhaust of diesel engines has been widely been a concern in many countries (1–3). Therefore, developing and seeking alternative diesel fuels, without modifying engines, has become an important issue. Biodiesel is now playing an important role on the alternative fuel market. Several states in the U.S. are pushing for a greater use of biodiesel, and the federal government is using a tax credit as the incentive for developing biodiesel (4). It has been known that the use of biodiesel in diesel engine can reduce hydrocarbons (HC), carbon monoxide (CO), carbon dioxide (CO2), sulfur dioxide (SO2), and PAHs emissions and slightly increases the brake specific fuel consumption (5–12). However, it should be noted that the use of biodiesel might lead to an increase on NOx emissions (13). But in our previous research, no statistically significant differences on NOx emissions were found when fueled biodiesel blends with the diesel engine in comparison with the use of premium diesel fuel (PDF) (14, 15). Similar results can also be seen in other studies (5, 6, 10). In addition, both positive or negative effects on particulate matter (PM) emissions were found in different types of biodiesel (12, 16–21), vehicle engine (5, 18, 19), and engine load (12). Our previous research has found that PM emission levels were decreased with the content of palm-biodiesel from 0% to 10% in palm-biodiesel blends but increased from 10% to 100% (22). In order to achieve low emissions from diesel engines, both the use of emulsified diesel and the use of additive have also been investigated. The use of water emulsified diesel could not only slightly improve the brake efficiency but also significantly reduce the formation of thermal nitrogen monoxide (NO), soot, hydrocarbons, and PM in diesel engines (23–32). In order to further improve the physical properties of emulsions, methanol has been added into the animal fats to form a more stable biofuel emulsion (33). Regarding adding additive in diesel fuel, an oxygenated diglyme additive was known to enhance both the nitrogen dioxide (NO2) emission and combustion efficiency, accompanied with the decrease in the fuel consumption rate, brake-specific fuel consumption, smoke opacity of PM, and emission of CO (34). The use of coagulant as an additive was found to be able to significantly improve the operating time of the media filter by reducing the rate of clogging and enhancing the turbidity removal (35). Recently, a biosolution of the natural organic enzyme-7F (NOE-7F) has been used as an additive in emulsified fuels by our research group. NOE-7F was found with a catalytic effect to elevate the combustion efficiency and decrease pollutant emissions during the combustion process. In addition, NOE-7F could also stabilize the emulsified fuels and enhance energy saving (36). VOL. 42, NO. 10, 2008 / ENVIRONMENTAL SCIENCE & TECHNOLOGY
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TABLE 1. Physical and Chemical Properties of PDF and Pure Soy-Biodiesel (B100)
a
fuel parameter
PDFa
pure soy-biodiesel
Analytic method
flash point, °C pour point, °C viscosity, cSt at 40 °C cetane index cetane number sulfur content, ppmw polyaromatic content, wt % density, g mL-1 at 15 °C carbon residue, wt % distillation, T90, °C ash, wt % residue, vol % lower gross heating value (cal g-1) corrosiveness (3 h at 50 °C)
89 -10 2.70 52.4 55.7 29 0.5 0.8310 0.06 315 0.001 0.03 10485 1a
168 14 4.41 49.3 61.3 NDc (
