Charles L. Peterson

CARBON CYCLE FOR RAPESEED OIL BIODIESEL FUELS

Abstract The greenhouse effect, thought to be responsible for global warming, is caused by gases accumulating in the earths atmosphere. Carbon dioxide, which makes up half of the gas accumulation problem, is produced during respiration and combustion processes. This paper provides an outline of the carbon cycle for rapeseed oil-derived fuels. Plant processes, fuel chemistry and combustion are examined with respect to carbon. A diagram is presented to interpret the information presented graphically. A comparison of carbon dioxide emissions from the combustion of rapeseed oil biodiesel and petroleum diesel is made. Complete combustion converts hydrocarbon fuels to carbon dioxide and water. The carbon cycle consists of the fixation of carbon and the release of oxygen by plants through the process of photosynthesis, then the recombining of oxygen and carbon to form CO 2 through the processes of combustion and respiration. The carbon dioxide released by petroleum diesel was fixed from the atmosphere during the formative years of the earth. Carbon dioxide released by biodiesel is fixed by the plant in a recent year and is recycled. Many scientists believe that global warming is occurring because of the rapid release of CO 2 in processes such as the combustion of petroleum diesel. Using biodiesel could reduce the accumulation of CO 2 in the atmosphere.

Winter rape oil fuel for diesel engines: recovery and utilization.

Although vegetable oil cannot yet be recommended as a fuel for general use, considerable progress in recovery and use of rapeseed oil (Brassica napus L.) for diesel operation has been made. Operation of a small-scale screwpress plant (40 kg/hr) was demonstrated. Maintenance of screw and end rings was a major problem. The plant has operated with a recovery efficiency of 77% and has processed 10,100 kg of seed in 230 hr. High viscosity of the rapeseed oil and its tendency to polymerize within the cylinder were major chemical and physical problems encountered. Attempts to reduce the viscosity of the vegetable oil by preheating the fuel were not successful in sufficiently increasing the temperature of the fuel at the injector to be of value. Short-term engine performance with vegetable oils as a fuel in any proportion show power output and fuel consumption to be equivalent to the diesel-fueled engines. Severe engine damage occurred in a very short time period in tests of maximum power with varying engine rpm. Additional torque tests with all blends need to be conducted. A blend of 70/30 winter rape and No. 1 diesel has been used successfully to power a small single-cylinder diesel engine for 850 hr. No adverse wear, effect on lubricating oil or effect on power output were noted.

Ethyl ester of rapeseed used as a biodiesel fuel—a case study☆

Abstract A 1994 Dodge 2500 turbocharged and intercooled diesel pickup fueled with 100% ethyl ester of rapeseed oil was driven by personnel representing the University of Idaho, Agricultural Engineering Department from Moscow, Idaho to Los Angeles, California and back to Moscow and then from Moscow to Ocean City, Maryland, east of Washington, D.C. and back to Moscow, Idaho. These trips covered a total of 14,069 km (8742 miles). The truck averaged 7.76 km/l (18.7 mile/gal) using 1772 l (468 gal) of ethyl ester of rapeseed oil fuel. No problems or unusual events were encountered with the trucks operation. The truck was completely unmodified as to the engine and fuel system. The fuel required for the trip was all processed in the Agricultural Engineering Laboratory at the University of Idaho and was carried on-board as no refueling facilities were available away from Moscow, Idaho. This is believed to be the first coast-to-coast and back run on 100% biodiesel.

A rapid engine test to measure injector fouling in diesel engines using vegetable oil fuels

Short engine tests were used to determine the rate of carbon deposition on direct injection diesel nozzles. Winter rape, high-oleic and high-linoleic safflower blends with 50% diesel were tested for carbon deposit and compared to that with D-2 Diesel Control Fuel. Deposits were greatest with the most unsaturated fuel, high-linoleic safflower, and least with winter rape. All vegetable oil blends developed power similar to diesel fueled engines with a 6 to 8% greater fuel consumption.

Used Vegetable Oil Fuel Blend Comparisons Using Injector Coking in a DI Diesel Engine

An imaging system was used to compare injector coking when used vegetable oil from local grocery store deli fryers was used as a diesel fuel replacement in small proportions. Fuel blends containing from 2.5% to 20% used vegetable oil were studied to determine which oil fuel blend would be optimal for future engine testing. The 2.5% oil fuel blend had injector coking levels slightly more than that of diesel fuel, while higher blends tended to have significantly higher injector coking levels.

Biodiesel Testing in Two On-Road Pickups

Two on-road diesel pickups were operated on a mixture of 20% Biodiesel and 80% diesel for 80,000 kilometers (km). The engines were unmodified, but modifications were made to the vehicles for the convenience of the test. Fuel mixing was done on-board to extend the driving range to over 5,000 km between Biodiesel fill ups. Chassis dynamometer testing, injector coking, engine compression, injector valve opening pressures, and engine oil analyses were done at regularly scheduled intervals to monitor the engine performance parameters. RME produced 5% less power than D2, while 20RME and 20RAW produced one percent less power than D2. Smoke density was reduced 39% with RME, while 20RME increased 18%, and 20RAW decreased smoke density by 3.1 times that of D2. Emissions tests with a chassis transient dynamometer at the Los Angeles Metropolitan Authority Emissions Test Facility resulted in a decrease in HC (20%), CO (25%), NOx (2.6%), PM (10.9%), and there was no difference in CO{sub 2} with 20 RME compared to D2.