JGSEE and Kyoto University 2nd Joint Int. Conference on "Sustainable Energy and Environment" swissotel NAI LERT PARK, Bangkok, Thailand Nov. 21-23, 2006 Influence of the Biodiesel Tempura Oil on Diesel Vehicles K. Nakamura / City of Kyoto M. Shioji / Kyoto University M. Ikegami / Fukui Institute of Technology Y. Hanada / Mitsubishi Fuso Truck and Bus Co. M. Matsushita / Shimadzu Techno-Research Inc.
BDF Production Project in Kyoto City since 1997 - Challenge of Kyoto City - Waste Edible Oil (used "Tempura Oil") 220 vehicles B100 Garbage Truck Biodiesel Fuel (BDF) B20 City Bus 80 vehicles - Use of BDF about 5,000 liters / day 1.5 million liters / year - Reduction in CO 2 by about 4,000 tons / year
Viewpoints of BDF Production Project in Kyoto City - Waste edible oil recycling - Reduction of automobile exhaust emissions - Reduction of carbon dioxide emissions - Live education about environmental problems - Vitalization of local communities
Contents of this paper - Motives and Objectives - Short-term influence on diesel vehicles fuel injection and supply equipment fuel filter plugging / deposit formation in injection pump - Long-term influence on diesel vehicles metals and rubbers corrosion and degradation state of fuel supply system
Motives and Objectives - Apart from the virgin vegetable oil, edible oil contains a variety of components A great fluctuation of the properties Some troubles in vehicle operation - Investigate the short-term and long-term influences on the actual vehicles (garbage trucks in Kyoto City) - Demonstrate the results of fleet tests -Examine the solutions for trouble and improvement measures Reflect the preliminary standards of BDF
Background in short-term influence with the use of BDF - Stringent regulation of exhaust-gas emissions from the diesel vehicles has stimulated to develop the technologies for clear diesel engine mainly in fuel-injection systems including fuel pump, injector and filter. - Such engine modifications may influence the operation with different qualities of BDF. - In a shorter period after the start of the BDF production project in Kyoto City, several troubles such as engine starting happened. - The short-term influence accompanied by the use of BDF is investigated.
Situations of the trouble happened with the vehicles at the long-term exhaust emission standards (1998 regulation) - number of garbage trucks in Kyoto City 1994 regulation; 121 in 2001 43 in 2004 1998 regulation; 78 107-1998 reg. suffered the engine starting trouble exchange fuel filter and fuel pump(!!) - Those troubles scarcely happened in 1994 reg. - Difference in vehicle construction between 1994 and 1998 regulation vehicles
Specifications of both engines and fuel-injection systems in 1994 and 1998 regulation vehicles - distribution pump and increase in fuel flow-rate in-line pump distribution pump injection pressure is elevated injection pump was cooled by the fuel increase the fuel flow-rate - fine-mesh filter and aspiration fuel-supply system filter mesh-size; 12 µm 5 µm filter area increases more than four times fuel supply system; pressurized aspiration fuel-supply pressure was lowered
Decomposition research of the fuel injection systems at 1998 regulation vehicle dark brown and tar-like matter Accumulated matter at the bottom of TCV hole
Analysis of adhesive substances to fuel filter - Fine-mesh fuel filter was frequently clogged in 1998 regulation vehicle - Adhesive substances were analyzed: a) Glycerin as a by-product Test sample includes glycerin a lot. b) Epoxy resin as a paint Benzene ring, aromatic ether bond and epoxy resin were not detected. c) Primary elements of catalyst and metals K, Al, Si, Fe, Zn, Al as a pipe material were detected.
Analysis of residuals in injection pump - Engine starting trouble is recovered by the change of injection pump - Viscous matters at the TCV hole were analyzed: a) Glycerin Glycerin content was 40 % b) Metals Fe; 26 mg/kg, K; 48,000 mg/kg Cu, Zn, Al and Pb were not detected c) Paint and Polymer Sample contained no paint and polymers.
Solutions for Vehicle Trouble (1998 regulation vehicles) - Fuel-filter plugging and bad operation of fuel pump and TCV caused engine troubles. - In the severe conditions of a higher fuel flowrate and a finer-mesh fuel filter, the residuals adhere to the filter and accumulate in the pump. - When the insufficiently refined fuel is supplied, solved glycerin is extracted to accumulate due to the change of temperature and pressure. - Viscous matters arise the bad operation of the sliding parts, and at last the trouble of engine stop happen.
Technical Measures for Improvement - To solve the trouble, the degree of the fuel refinery must be elevated as high as possible. - Fuel refinery method was changed from dry process to wet process and completely remove the contaminants such as the remaining glycerin. - Modification in the fuel production process: a) decompression removal of water and methanol b) introduction of wet refinery (wash with water) c) alteration of the filter mesh-size from 5 to 1 µm
Change of properties with the alteration to fuel production method year of production until 2001 from 2002 Process dry refinery wet refinery Water content (ppm) 649-800 300 Flash point (degc) 32-33 198 Mono-glyceride (%) 0. 57-0.76 0.82 Di-glyceride Tri-glyceride (%) 1.17-1.26 1.31 (%) 10.16-11.28 7.94 Free glycerin (%) 0.059-0.300 0.005 Methanol (%) 0.76-0.80 < 0.01 Alkali metal (mg/kg) 101 2
Change of the fuel filter with the use of different BDF (a) until 2001 (b) from 2002 Outside look of fuel filter
Change of the fuel filter performance 100 Pressure Loss kpa 10 1 within the usual operation Operation Limit beyond the usual operation year of prod. filling ratio in tank capacity 2001 half 2001 full 2002 half 2002 full New element 0.1 1 10 Flow rate L/min Pressure drop with filter against flow rate
Background and Contents in long-term influence with the use of BDF - Engine body and elements of injection systems in current diesel vehicles are designed on the supposition that diesel oil is used as a fuel. - It is necessary to investigate the long-term influence of BDF on the materials such as metals and rubbers. - Corrosion of covered cupper and deterioration of fuel hoses were investigated on fuel systems with the neat use (100% BDF) for four years.
Elements of fuel system for research and their materials 1. Feed pipe Steal (Copper plate) 4. Feed pipe Steal (Copper plate) 5. Return pipe Steal (Copper plate) 6. Hoses NBR 13 1 8. Suction pipe Steal (Copper plate) 12. Injection pipe Steal 12 13. Leak off pipe Steal (Copper plate) 4 5 6 8
Situation of deterioration in metals Corrosion hole: depth about 15 µm 25 µm 25 µm Microscope photograph of the crystal structure in the return pipe at cross-sectional view
Situation of deterioration in rubbers - Micro-crack occurred in the inner side and the rubber became harder, thus reaching the time for changing. - It was necessary to select the fluorine rubber and string-slot rubber applicable to BDF at the purchase of new vehicle. - After the alteration for fluorine rubber in packing of fuel-tank cap and for string-slot rubber in fuel hoses, the problem has never occurred.
Summary (1/2) Feasibility of biodiesel fuel application on diesel vehicles are demonstrated. For all garbege trucks (about 220 vehicles) in Kyoto City in Japan, the short-term and long-term influences of BDF was investigated; 1. When insufficiently refined fuel is supplied to injection pump, contaminations are accumulated in the fuel filter, resulting in the engine starting trouble. 2. Insufficient refined fuel contains by-product glycerin and potassium used as catalyst, which adhere to the fuel filter for plugging.
Summary (2/2) 3. To solve the trouble, it is necessary to alter the BDF production method from dry process to wet process. In addition, the contaminations are removed by using a fine-mesh filer. 4. For the long-term influence on the vehicle with the neat use (100% BDF), in the return pipe with a higher temperature, a progress in the corrosion was observed. 5. For the NBR rubber hoses, the micro-crack occurred in the inner side, however, use of the fluorine rubber and the string-slot rubber can solve this problem.
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