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BIOFUEL IN RWANDA: Potentialities and opportunities of the methyl ester vegetable oil (MEVO) and of the pure vegetable oil (PVO)

Launched in 1992 on the initiative of the oilseeds producers joined together within the die of oils and plant proteins, the Diester - contraction of Diesel and Ester - is the name given to biofuel resulting from vegetable oils. It is just a methyl ester of vegetable oils (MEVO) obtained according to the following equation:
1 ton of vegetable oil + 0, 1 T of methanol = 1 T of diester + 0, 1 T of glycerin.

Experimental Procedure

Palm oil transesterification with methanol using NaOH as catalyst in a batch was studied using a methanol/oil weight ration and we followed the progress of the reaction by the determination of total methyl esters and glycerol.

How Biodiesel works

Biodiesel runs in any unmodified diesel engine. There is no “engine conversion” typical of other alternative fuels. The diesel engine can run on biodiesel because it operates on the principle of compression ignition whereby air is compressed and the fuel is sprayed into the ultra-hot, ultra-pressured combustion chamber. Unlike gasoline engines, which use a spark to ignite the fuel/air mixture, diesel engines actually use fuel to ignite hot air. This simple process allows the diesel engine to run on thick fuels. Since biodiesel is chemically similar to petroleum diesel fuel, you can pour biodiesel right into the fuel tank of any diesel vehicle. Biodiesel has lower emissions, it is made domestically (which increases national security), it does not affect engine performance and biodiesel is produced from plants. Since plants are a product of solar energy, biodiesel is “liquid solar fuel”.

Biodiesel Benefits

 Biodiesel runs in any conventional, unmodified diesel engine. Non engine modifications are necessary to use biodiesel and there is no “engine conversion”. In other words, “you just pour it into the fuel tank”.

 Biodiesel can be stored anywhere that petroleum diesel fuel is stored. All diesel fueling infrastructure including pumps, tanks and transport trucks can use biodiesel without modifications. Biodiesel reduces carbon dioxide emissions, the primary cause of the Greenhouse Effect, by up to 100 %. Since biodiesel comes from plants and plants breathe carbon dioxide, there is no net gain in carbon dioxide from using biodiesel.

 Biodiesel can be used alone or mixed in any amount with petroleum diesel fuel. A 20 % blend of biodiesel with diesel fuel is called “B20”, a 5 % blend is called “B5” and so on.

 Biodiesel is more lubricating than diesel fuel, it increases the engine life and it can be used to replace sulfur, a lubricating agent that, when burned, produces sulfur dioxide - the primary component in acid rain. Instead of sulfur, all diesel fuel sold in France contains 5 % biodiesel.

 Biodiesel is safe to handle because it is biodegradable and non-toxic. According to the Biodiesel Board, “neat biodiesel is as biodegradable as sugar and less toxic than salt”.

 Biodiesel is safe to transport. Biodiesel has a high flash point, or ignition temperature, of about 300 deg. F compared to petroleum diesel fuel, which has a flash point of 125 deg. F.

 Engines running on biodiesel (add a verb here) normally and have similar fuel mileage to engines running on diesel fuel. Autoignition, fuel consumption, power output, and engine torque are relatively unaffected by biodiesel.

 Biodiesel has a pleasant aroma similar to popcorn popping in comparison to the all-too-familiar stench of petroleum diesel fuel.

Conclusions

 In Rwanda, several oil plants hold high potential for use in biodiesel production. These plants and their potential reported oil yields are:

 Palm oil (yield 5,950 liters/ha), avocado (yield 2,638 liters/ha), jatropha (yield 1,900 liters/ha), and castor bean (yield 1,413 liters/ha). By comparison, reported oil yields from soybean, which is commonly used to produce biodiesel in temperate climates is only 446 liters/ha.

 Palm oil has the highest yield of common agricultural crops, and new varieties have been developed for high altitude (950 m) and low temperature production. These varieties have great potential for cultivation in Rwanda. However, as full production from time of planting requires approximately three years, intermediate crops must be considered. Avocado is widely cultivated in Rwanda, and currently the oil containing seeds are not utilized. This may be an excellent source of oil for biodiesel production and could provide additional income for rural farmers. Another option might be to intercrop new palm oil plantings with a fast growing, high oil yielding plant such as castor bean. This could allow immediate return while oil yield palm plants are maturing.

 Finally, drought tolerant plants such as jatropha which can live for 40 years, and provide a high value oil, might be suitable for marginal areas.

 In the area of biodiesel, the IRST, is at the cutting edge of research aimed at improving biodiesel production using micro-technology. The IRST has developed a working prototype of a chemical reactor for manufacturing biodiesel that is so efficient and portable it could enable farmers to produce a cleaner-burning diesel substitute on their farms using seed crops they grow on their own land.

Persons in charge of the project

 Dr. Ir. NDUWAYEZU Jean-Baptiste: Ph. D. in Agroforestery, Director General of the IRST.
 Dr. Ir. RURIHOSE Fidèle: Ph. D. in Applied Mechanics (Energy), Director of the CRSA.
 Dr. KARANGWA Pierre-Célestin: Ph. D. in Physical Science, Researcher within the l’IRST-CRSA and Coordinator of the Project.
 HAKIZIMANA Cyprien: M.Sc. in Chemical Science, Researcher within the l’IRST-CRSA.
 NSABUMUHIRE Innocent: M.Sc. in ICT, Researcher within the l’IRST-CRSA.
 NIYIBIZI Ananie: A0 in Chemistry, Technician within the l’IRST-CRSA.
 NGIRABAKUNZI RUDATINYA Benjamin: A0 in Chemistry, Technician within the l’IRST-CRSA.
 NZABONANTUMA Léonard: A0 in Civil Engineering, Technician within the l’IRST-CRSA.
 NYOMBAYIRE Lambert: A0 in Electricity, Technician within the l’IRST-CRSA.
 GIOVANNINI Philip: Ph. D. Biological and Agricultural Engineering, Technical expert in charge of mission - California, USA

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Références

1. Biodiesel Rwanda