Omförestrad rapsolja : egenskaper och framställning
The area of oil crops, mainly rape, in Sweden today is about 165 000 hectares. About 280 000 tonnes of the harvest are processed and give about 100 000 tonnes of vegetable oil. The main part is exported to a low world market price. This oil could better be used as a fuel in Sweden. Using the oil would give us a better environment and make us more independent of the oil producing countries. When the rape oil is transesterified, it can be used in all types of diesel engines. Much test work have been carried out, both short time bench tests and longtime practical tests. All the tests have shown good results. The main advantages are that the fuel is renewable and doesn’t give any addition of CO2 to the atmosphere. The transesterified vegetable oil is possible to mix with diesel oil. It also has a high flame point and is therefore easy to handle and store. Transesterified vegetable oil gives a little bit higher fuel consumption and a lower effect than diesel. To transesterify rape oil an alcohol, methanol or ethanol, is needed. To maintain the reaction at room temperature a catalyst is also needed, which can either be NaOH or KOH. The reaction formula is: 1 mol triglycerid + 3 mol methanol + catalysis <=> 3 mol ester + 1 mol glycerol + catalysis To get a high value fuel the ester also needs to be cleaned, which could be done with water. Much research at universities and industries around the world has been done on transesterified vegetable oil. The production is fully developed and tested. But so far only Austria has taken the step from research to industrial production through investment subsidies and tax allowance. They also allow the companies to buy the oil seed to world market prices. A lot of countries have plans to follow. In the northern countries both Sweden and Finland have far going plans. In Europe, France is building an industrial plant for a production of 400 000 tonnes of oil per year. One important factor for the production is the economy. The cost for transesterification in Sweden is 1.85 kr/l for a production of 13 000 tonnes per year and 2.95 kr/1 for a production of 400 tonnes per year. Totally the cost for the oil is 4.10 kr/l respectively 5.60 kr/l. This should be compared with the diesel fuel price which is 3 kr/l, taxes included. Transesterified rape oil is one of the best substitutes for diesel oil we have today, both from an economical and an environmental view. The vegetable oil however can only substitute a part of the diesel fuel consumption.
omförestring; rapsolja; alternativa drivmedel; biodisel; framställning; energi
Rapport - Sveriges lantbruksuniversitet, Institutionen för lantbruksteknik
Publisher: Institutionen för lantbruksteknik, Sveriges lantbruksuniversitet
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