Fire / Feu



Huile végétale, un carburant

Au Canada, 25 % de toute l'énergie utilisée dans les transports pour fins commerciales et récréatives ainsi que dans les véhicules marins, se trouve sous forme de gasoil pour diesels, soit 21 milliards de litres chaque année. Tout ce carburant produit, à son tour, 45 788 000 tonnes de gas à effets de serre. Par ailleurs, les particules de matières en suspension dans les gaz à échappements des moteurs diesel sont 20 % plus nombreuses que dans les moteurs à essence.

Une façon de réduire les effets nuisibles des carburants pétroliers est de permettre à l'huile végétale de prendre sa place parmi les carburants renouvelables utilisés dans le transport et le chauffage. Les huiles de fritures usées de l'industrie alimentaire, les huiles végétales renouvelables produite par l'industrie agricole, et même les gras animaux conviennent comme carburant. Parmi les avantages provenant du remplacement des carburants fossiles, on retrouve la réduction de la pollution de l'air, la réduction de l'émission des gaz à effets de serre et la conservation des ressources limitées en carburants fossiles.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[1] Transport Canada based on data from Statistics Canada Quarterly Report on Energy Supply-Demand in Canada , Cat 57-003

[2] Statistics Canada , CANSIM, Matrix 2483 (Figures are for 1998)

[3] Environment Canada , 1997, Trends in Canada’s Greenhouse Gas Emissions (1990-1995), Catalogue No. En49-5/5-8E, Ottawa (Figures quoted are for 1995)

[4] Environmental Health Criteria 171: Diesel Fuel and Exhaust Emissions. World Health Organization, Geneva 1996.

 

Vegetable Oil as Fuel


Wayne Groszko
Falls Brook Centre
February 2004

In Canada, 25% of all transportation energy use is diesel fuel for commercial, recreational and marine vehicles[1], some 21 billion litres each year [2]. This produces 45,788,000 tonnes of greenhouse gases[3]. Also, airborne particulate matter in exhaust from diesel vehicles is 20 times higher than for gasoline powered vehicles.[4]

One of the ways to decrease these impacts is to consider vegetable oil as a source of renewable fuels for transportation and heating. Waste fry oil from the food industry, fresh-pressed vegetable oil from agriculture, and even animal fat can be used as materials for fuel. The benefits of using these sources to displace fossil fuels can include reduced air pollution, reduced greenhouse gas emissions, and conservation of limited fossil fuels.

There are basically two common ways to use vegetable oil as a fuel in an engine. One way is to use straight vegetable oil, either waste fry oil or fresh-pressed oil. This requires an extra fuel tank and a system for heating and filtering the oil before it reaches the engine, because pure vegetable oil is too thick to work in the engine unless the oil is heated up. Another way is to convert the vegetable oil into biodiesel, which can be used in a diesel engine without any modifications.

What is Biodiesel?

Biodiesel is made from vegetable oil by a chemical reaction with methanol and lye (sodium hydroxide). It can be made using waste vegetable oil from the food industry, including french fry oil, or from fresh-pressed vegetable oil. It is now being made in commercial quantities of thousands of litres by numerous companies around the world. It can also be made at home with some fairly simple equipment and instructions. This requires care and caution because some of the materials are caustic (the lye), flammable (the methanol), and poisonous if ingested (both the lye and the methanol).

Pure biodiesel, called B100, works as a fuel in ordinary, unmodified diesel engines, but certain precautions have to be observed for good results. B100 has two characteristics that need to be considered: (1) it can dissolve neoprene rubber over time, so you would need to ensure that hoses and gaskets in the engine are made of another material, such as Viton, that is resistant to biodiesel; and (2) it "clouds" or "gels" at temperatures below about +5 degrees Celsius, so you have to be careful not to allow the fuel to get cold, or it will gel and block the fuel filter, preventing the engine from running until it warms up again. Other than that, there have been no serious changes in engine performance or durability reported from using B100.

Blends of between 5% and 20% biodiesel (B5 to B20), with the rest being petroleum diesel, have been used successfully in many kinds of diesel vehicles such as buses, cars, and trucks, with no modification to the vehicle. By using a lower blend, there is less risk of dissolving fuel gaskets or gelling in cold weather. For example, 10% biodiesel mixed with "winter" diesel should be operational down to about minus 39 degrees Celsius, according to one operator of biodiesel trucks in Quebec.


(photo: Falls Brook Centre)

In New Brunswick, Falls Brook Centre operated its "Climate Change Bus" on a blend of 30% to 60% biodiesel during its 2003 season (May to October), with excellent success. Montreal's public transportation system has also conducted a trial, using a biodiesel blend in 150 urban transit buses for a full year, including winter.

Biodiesel can also displace heating oil. The Chewonki Foundation in Maine, which produces its own biodiesel from local food industry waste, is using biodiesel in fuel-oil furnaces, in addition to fuelling diesel vehicles with straight B100 biodiesel.[3] (see this PDF file) .

Benefits of Biodiesel

When biodiesel displaces petroleum diesel, there is an estimated 78% average reduction of greenhouse gas emissions per litre, compared with petroleum diesel, over the life cycle of the fuel (National Biodiesel Board of the USA). Actual reductions depend on the source of the materials used to make the biodiesel. Greenhouse gas savings could be higher when biodiesel is made locally from waste food oil products. Several toxic air pollutants are also reduced by using biodiesel, including soot, particulates, carbon monoxide, and sulphur oxides, although nitrous oxide emissions may increase slightly. Biodiesel is non-toxic, biodegradable, and safer to handle than petroleum diesel. It requires no special storage considerations, because its flash point is higher than that of petroleum diesel.

Straight Vegetable Oil:

If you have a diesel vehicle and you are handy with modifying fuel tanks and lines, another way to bring renewable fuel into your life is to use waste fry oil directly in your vehicle. This requires you to install an extra fuel tank and a fuel heating and filtering system that uses the heat from the engine to keep the vegetable oil hot enough to work. In this system, the engine is first started on regular petroleum diesel (or any blend of biodiesel) in the regular tank, and run until it warms up the vegetable oil tank to the proper temperature. Then you turn a switch to bring the hot veggie oil to the engine. Before shutting off the engine, you switch it back to diesel for a couple of minutes.

Tim and Shelley Smith of Bridgewater, Nova Scotia, are using this system to run a Volkswagen Jetta. Straight veggie oil in a similar system was also used by New Brunswick's own Climate Change Caravan to fuel their bus on its cross-Canada journey in 2001. These experiences have shown that good filtering of the vegetable oil is important to lengthen the life of the engine.

The straight vegetable oil system requires some work to the vehicle, but it has advantages. The oil can be used directly, saving the methanol, lye, and processing effort that would have been required to make it into biodiesel.

Resources:

The most comprehensive book on using vegetable oil as a fuel is:  From the Fryer to the Fuel Tank, by Joshua Tickell

Also, there are several people in New Brunswick who are using and/or making fuels based on waste food oil. You can contact Wayne at Falls Brook Centre if you have specific questions. If we don't know the answer, we can try to direct you to someone who does. Phone: 506-375-4310,
email: wayne@fallsbrookcentre.ca