Kyambogo’s bio-ethanol fuel research promising
Sep 10, 2006
THE recent bio-ethanol fuel tests done by Dr. Bagenda Ssengonzi, the head of Kyambogo University Department of Mechanical Engineering and his team, have proved that ethanol distilled from Ugandan cereals and tubers can power industrial machinery.
THE recent bio-ethanol fuel tests done by Dr. Bagenda Ssengonzi, the head of Kyambogo University Department of Mechanical Engineering and his team, have proved that ethanol distilled from Ugandan cereals and tubers can power industrial machinery. The research started eight months ago.
Peter Okello-obeli, the university workshop manager, says two vehicles, Suzuki Samurai 1.5cc and Toyota Town ACE 1.8cc, which were formerly consuming petrol have responded well to the fuel, but the research is still going on. The university’s four-stroke generator has also worked well with the fuel.
“Ethanol is an organic chemical product distilled from local raw plants like cassava, millet, sorghum, maize and sugarcane (cereals and tubers) that contain carbohydrates and sugars. It is a hydro-carbon composition like oil,†Okello-obeli says.
He says the chemical is mixed with yeast, which catalyses the action of sugars and carbohydrates to form brew or beer. The process involves heating the beer. The vapour is cooled in a distillation column, forming ethanol. To a layman, ethanol is alcohol or crude liquor.
“So far, the distillation tests we have produce 93% alcohol content above the industrial fuel alcohol content. The production of liquor is the same, but the difference arises in the alcohol content of 40%,†Okello-obeli says. Industrial ethanol is supposed to have an alcohol content of 86% to run any machinery.
“This research looks at alternative fuel,†says Eng. Robert Kafeero Smart Motor World Limited’s general manager and a member of the research team. The Bio-ethanol research involved three stages. In the first stage, petrol and diesel engines were tested including the two and four-stroke generators.
The second stage targeted attaining the ethanol alcohol content of 86%. Before distillation, the mixed plant cereals produced 7% alcohol content. This stage is still being researched on.
The third stage looks at sustainability. Okello-obeli says the price of ethanol fuel must be competitive enough to beat the existing price of petrol or diesel.
“After achieving the last stage, we shall announce that there is market for the product. The engineering research is spread out to other stakeholders in different fields,†he explains.
The research team’s main challenge is sourcing funds. “We have funded the project and designed five distillation columns like the one we secured from USA,†he says.
Okello-obeli says their ethanol can be blended with petrol, but the ethanol must be 100% pure. However, Ethanol can be blended in various proportions with petrol, usually 5% to 10%.
Many states including USA blend 10% of ethanol with petrol to get the fuel that cars use. However, Brazil mixes 24% of ethanol.
According to Enger Smith’s Environmental Science , Brazil is the largest producer of ethanol fuel from biomass. The low price of sugar coupled with the high price of oil prompted Brazil to use sugarcane as an energy source.
Ethanol fuel is exploited on a large-scale in Zimbabwe, Malawi and Kenya. Malawi and Zimbabwe, being landlocked countries have reduced their expenditure on on fuel imports.
Ethanol acts as an octane enhancement, fuel extender or replacement, anti-knocking and an oxygenating agent.
Ethanol also comprises oxygen and alcohol, therefore, petroleum with ethanol as an anti-knocking agent protects the engine. Using ethanol in place of tetraethyl lead prevents poisonous emissions. Ethanol can be used as an alternative to leaded fuel.
The United Nations Environment Programme (UNEP) has spearheaded and coordinated a programme to phase out leaded petrol worldwide.
In 2001, UNEP sponsored a continental conference to draw a programme that would phase out the use of lead in Dakar, Senegal.
The Dakar Declaration set December 2005 as the deadline for the complete phase-out. Other countries including Uganda are now importing only unleaded petrol.
Vehicles that use leaded petrol produce exhaust fumes that are harmful to our health. Lead enters the body through inhalation or ingestion of lead-contaminated soil, dust or paint.
Elevated levels can adversely affect the mental development and performance of the kidney and blood chemistry.
In congested urban areas, exhaust fumes from vehicles using leaded petrol account for 90% of airborne lead pollution. Lead also contains green house gases contributing to environmental degradation and global warming.
Okello-obeli says the bi-products of ethanol combustion are normal compounds in the air and are not dangerous to the environment.
“Ethanol is not corrosive and is lighter than petrol. Petrol additives make it heavier. Petroleum’s ability to vapourise and flare up is higher than ethanol. During combustion, petroleum burns faster,†he adds.
Okello-obeli says when using ethanol fuel, one must first alter the main metering jet in the carburettor. In most carburetors, there is a threaded brass plug with a specific sized hole drilled through the centre. This hole, the main jet orifice, and its diameter, dictate how rich or lean the air/fuel mixture will be when a car is travelling.
He says the smaller the hole, the less the fuel will blend with the air and the leaner the mixture. As the orifice is enlarged, the mixer gets richer. Since alcohol requires a richer air/fuel ration, it is necessary to bore out the main jet orifice when using ethanol fuel ranging from 20 to 40%.
Okello-obeli says if you choose to drill the jet to a larger dimension, the diameter should be increased between 10 to 32%.
He says in extremely cold climates, it may be necessary to preheat alcohol fuel before it enters the carburettor float bowl. Alcohol doesn’t vapourise as easily as petrol.
Starting a car in cold weather can be a problem, especially if the engine is cold. To alleviate this undesirable situation in the morning, you must open up an air cleaner and apply thinner, which is used in the paint industry.
Since diesel engines do not use conventional spark ignition systems, it is difficult for pure ethanol fuel to ignite within the combustion chamber. In this case, you can use vapourised ethanol along with diesel. The simplest way is to mount an automobile carburettor onto the diesel’s air intake.
To successfully run a generator, you need to control the amount of air inside by putting the choke midway. In case of cold starting, open the generator plug and put a little petrol on plug spark and the engine will start. According to the research, one litre of petrol and 1.2litres of ethanol can run a 2.1kVA generator for one hour.
“A generator running on ethanol fuel can be run inside the house without being worried about emitting carbon monoxide, unlike the petrol generator,†says Okello-obeli.