Biofuels Biodiesel and bioethanol

Exercise in groups For what purposes do we use energy? Which energy sources do you know ?

World energy consumption

XXs energy consumption (Please add statistic showing energy consumption by source for your own country)

Fossil fuels FOSSIL FUELS originate from organisms that lived millions of years ago. Examples of fossil fuels: coal, oil, natural gas,

Biofuels BIOFUELS originate from organisms that lived recently. Examples of biofuels: wood, straw, biodiesel, bioethanol, biogas

CO 2 is developed- whether you burn biofuels or fossil fuels. The difference is... Energi, vand og CO 2

CO 2 Fossil fuels are not CO 2 -neutral When you burn fossil fuels the atmospheric concentration of CO 2 rises

CO 2 Biofuels are CO 2 -neutral When wood - or another biofuel – is burned, the CO 2 concentration will not rise. CO 2 is developed but only the same amount that the trees (plants) have used in photosynthesis while growing.

Political goals The increased amount of CO 2 in the atmosphere contribute to the greenhouse effect/global warming. EU climate policy has the following main objectives reduction of greenhouse gases use of renewable energy increased energy efficiency. In this context agriculture can play a part by growing crops that are wholly or partly used to produce energy.

Some biofuels Fuel typeSourceKan replace/supplement BiodieselVegetable oils and animal fats Diesel Bio ethanolGrain, corn, grasses, straw, can, willow, residual wood (carbohydrate part ) Gasoline BiogasManure, straw, fat waste, grasses, whey (org. waste) Natural gas

Production of biodiesel FatEthanolBiodiesel

What kinds of fats can be used? For instance Animal fat (abattoir) Used frying oil Rapeseed Discuss the use of these fats

Here you could introduce the biodiesel experiment…

How to make ethanol Alcohol/ethanol can be made by fermentation of sugar. The starting material need not be pure sucrose, but may be biomass/plant material which is rich in carbohydrate. Before the fermentation can take place some preliminary steps are necessary, however Sugar Fermentation Alcohol (ethanol)

Carbohydrates The following slides give a brief overview of carbohydrate structure. In stead of showing the slides you could ask the students find information about mono-, di- and polysaccharides themselves. Types, structure, where do we find the different types etc.

Carbohydrates Carbohydrates are built up of carbon, oxygen and hydrogen. Carbohydrates are divided into monosaccharides, disaccharides and polysaccharides. An example of a simple carbohydrate is dextrose (glucose), which is the sugar made in photosynthesis. In a dextrose molecule the atoms are organized in ring in the shape of a hexagon.

Monosaccharides Other carbohydrates such as fruit sugar (fructose) has a structure like a pentagon. Glucose and fructose are examples of monosaccharides. Mono means one and says they have only contains one “sugar ring”. A lot of different carbohydrates can be made of these simple building stones.

Sugar Plain sugar (sucrose) and maltose is made of two sugar rings that are linked together. Therefore they are called disaccharides (“di” means two).

Starch – a polysaccharide Polysaccharides er made by may ”sugar rings” (poly means many). Starch is one example of a polysaccharide, that is made by long chains of dextrose

Cellulose – another polysaccharide Another example of a polysaccharide which is composed of glucose chains is cellulose, which is found in plant cell walls. The bonds between the dextrose molecules in cellulose are not so easy to break as in starch. This difference also is important in the production of bioethanol

Fremstilling af bioethanol Sugar Fermentation Alcohol (ethanol) During pre-treatment the polysaccharides are cut into monosaccharides before fermentation. The pre-treatment needed depends of the type of biomass used. Pre-treatment

1. generation bioethanol The raw material can be sugar cane and sugar beet (containing carbohydrate in the form of sugar), maize or cereal (containing carbohydrate in the form of starch). This requires only a light pretreatment because starch can be broken down. Light pre-treatment

2. generation bioethanol The raw material can be straw, corn stalks, wood (contains carbohydrates in the form of lignocellulose ) These plants contain carbohydrates that are difficult to extract and convert into ethanol = energy intensive pretreatment. Benefits: The method uses waste material, which is cheap and present in large amounts. Energy intensiv pre- treatment

IBUS-plant – a second generation plant using straw Pretreatment of straw : Chopping (1-5 cm long pieces ) Soaking in water Heating the " straw soup" at high pressure ( ° C, bar) for minutes The carbohydrates in the heated " straw soup" are degraded by a number of enzymes added to the sugar

IBUS-plant – fermentation and waste After pre-treatment, the sugar is ready to be converted to ethanol using yeast. After fermentation, filtration and distillation you have pure ethanol. The residual from the production is solid biofuel and liquid molasses: The biofuel is used as an energy source for the pre-treatment and distillation. The molasses can be used as animal feed.