Bio-fuels

A biodiesel is a non-petroleum-based diesel fuel made up of short chain alkyl (methyl or ethyl) esters, generally produced by the transesterification of vegetable oils, animal fats or other organic materials which can be used (alone, or blended) in unmodified diesel-engine vehicles.
There are many different types of bio-fuels such as: bio-alcohol (ethanol, propanol, butanol), bio-diesel (most common bio-fuel in Europe), bio-gas, solid bio-fuels (wood, grass cuttings), syngas.
biofuelsCycle.jpg
Image (W): <http://arstechnica.com/old/content/2008/08/engineering-better-biofuels-through-genome-research.ars>



Image (W) shows the cycle of bio-fuels. The solar energy and carbon dioxide from the atmosphere help the plants to grow (biomass) then the organic compounds are harvested and pre-processed. The next part of the cycle shows the cellulose being broken down into sugars, and then into ethanol. The ethanol is used as the bio-fuel and is disributed to cars, trucks and airplanes. These release CO2 back into the atmosphere and with the solar energy from the sun, the cycle is able to start over.

History of Bio-fuels


Bio-fuels have been in use ever since man discovered fire. Wood was the very first bio-fuel used long, long ago for making fires for heat and cooking. Bio-fuel was used long before the discovery of fossil fuels. The original way to use energy was by burning the organic, bio-fuels found in the environment. Once fossil fuels were found, bio-fuels were forgotten. At the time, the fossil fuels were plentiful, so they were very inexpensive, then as time went on, and the fossil fuels began to ran out, scientists looked back at what their ancestors used before them.

Rudolf Diesel invented the diesel engine. His design was for the engine to run on peanut oil, and as time went on new and better inventions were created. They were able to run completely on bio-fuel, but the crude oil being found at the time was much cheaper and more efficient, so that was used instead. During World War II, there was a shortage of fuels, so bio-fuels were needed. Once the war was over however, the oil was once again being traded, so bio-fuel was no longer a necessity. With the increased supply of fossil fuels the interest in bio-fuel disappeared. Throughout the past few decades, the need for a new, cleaner fuel source has been growing and growing because of our diminishing supply and because of all of the environmental problems we now know it causes.

Bio-fuel Applications

buysss.jpg
Image (Y): <http://en.wikipedia.org/wiki/Biodiesel#Applications>

B100 is 100 % biodiesel. Biodiesel can be used in it's pure form (B100), or with different amounts of petrodiesel blended in (i.e. B5, B25, B50 etc). Bio-fuels are used to power many different types of machinery, including vehicles, trains, buses (like Image (Y) to the right, it is run on bio-diesel from soybean) and other forms of transportation and
pure_biodiesel_from_soybeans.jpg
Image (Z): <http://en.wikipedia.org/wiki/Biodiesel#Applications>
farm machinery. It can also be used to produce heat (to fuel fireplaces - that do not need a chimney). Bio-fuels are a renewable energy source that we can use as a substitute for our presently used petroleum and other fossil fuels. Most machinery that uses non-renewable diesel fuels as a power source often can handle a blend of bio-diesel and petrodiesel without modification, but they can usually be easily adjusted if needed. Likewise, E100 is 100% ethanol. It can also be blended in different concentrations, and that is told by the number following the E. To use ethanol in an engine instead of regular gasoline, it must be a special type (cars - "flex-fuel") that can handle both fuels.

Canola and soybean (Image (Y) and (Z) ) oils are often used to produce bio-diesel. Ethanol is often produced from corn.

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Graph 1: <http://biofleet.net/index.php?option=com_content&task=view&id=36&Itemid=45>
This graph clearly shows how the more percent bio-diesel used, the less emissions produced.



Pros and Cons of Using Bio-Fuels

Pros

Cons

  • Bio-fuels are biodegradable, they can be produced by organic materials and are a renewable fuel source.

  • We can produce the fuel here, so we do not need to be dependant on foreign countries for our fuel source (also, we can produce it here so diminishes transport costs and pollution). We can be more independent as a nation.

  • Bio-fuels are made out of organic materials; crops can easily and quickly be produced (grown on a farm), instead of fuels that take thousands of years to be produced (fossil fuels) and are difficult to extract (i.e. mining).

  • The abundance of crop and it's ability to be extracted easily allow the cost of bio-fuels to sometimes be less than other types of fuels.

  • There are many eco-benefits in addition to the economic benefits. Bio-fuels are much cleaner / better for the environment.They produce way less harmful emissions than burning gasoline, coal or other fossil fuels.

  • Emit less particulate pollution.

  • Only emit into environment the carbon dioxide that their original plants absorbed (they are carbon neutral/have a net zero carbon footprint or emissions).

  • Don't just have to grow crops to produce bio-fuels, but any organic waste (such as vegetable oils or coffee grinds) can be used. These are saved from just being thrown out to the landfills, and are reused in the production of bio-fuels. This organic waste will have provided us with 2 very important processes. Giving us nutrition (food) and powering our vehicles (fuel).

  • It is easy to convert to this type of green energy - just keep using the machinery you have and add in the bio-fuel, instead of having to get a special apparatus to receive the energy.

  • Bio-fuels are not as effective as fossil fuels or other non-renewable power sources. They do not generate as much power as petroleum or diesel fuels.

  • To be able to produce enough crops for mass production of bio-fuels, a huge amount of land would need to be reserved for growing them. This land would need to be cleared, and dedicated solely to growing crops for the production of bio-fuels. This would result in many of the natural plants and animals of the area to lose their homes and habitats. There will be no where for them to go, as our space on Earth is already limited, so they would suffer the consequences.

  • The great need for crops for the production of bio-fuels would cause there to be a decreased amount of crops being grown for food. There are already so many starving people in world. If a large amount of our food source was cut out, people all over the place would starve. Many, many more people would get sick or die if the amount of food is not kept up.

  • This decreased amount of food would cause the price of it to increase (as there would no longer be enough of it). Even more people would go hungry (not just the developing countries, but even lower and middle class people of all parts of the world) because they would not be able to afford the food that we do have left.

  • Fermentation is often used for producing bio-fuels, and that is very expensive process.

  • Bio-diesel has different solvent properties than petrodiesel, so it degrades the rubber gaskets and hoses on older cars faster (newer cars have better materials).

  • To replace only 5% of America's diesel with bio-diesel, it would use up about 60% of today's soy crops. That would be a drastic amount of loss of soybeans for such a small amount of fuel.

  • 2005 study by David Pimental concluded that to grow and convert crops of corn to ethanol takes 29% more energy than the final bio-fuel is able to generate. Similar results for soybeans into bio-diesel. No energy benefit.
  • People will assume that this is perfectly green, so they don't need to conserve it, but it still costs a lot of money and uses a lot of energy to produce. People will adopt a "false sense of security".
  • Sometimes - depending on organic produce used - an offensive smell is produced (i.e. greasy fries).

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Image (V): <http://www.celsias.co.nz/article/kiwi-biofuel-initiative-scores-international-recog/>

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Bio-fuels are being used more and more. As you can see in Image (V), there is a gas pump that pumps out bio-fuels. The green pump is bio-diesel B20 (20% bio-diesel), the yellow pump is E85 (85% ethanol) and the blue is B10 (10% bio-diesel). Hopefully as our world continues to develop, we will see more and more of these pumps available for people to use.

Many places around the world (including the UK and the state of Minesota) have decreed that all diesel sold must have a certain percentage of bio-diesel blended in. They may just be small amounts like 2-3%, but for every bit of diesel in the whole state to have 2%, it makes a big difference.


Research and Development

Organic Chemistry Bio-fuel Production

In 2009 researchers at the University of Wisconsin-Madison developed the first single step production of a bio-fuel precursor from untreated biological/agricultural waste. They have been able to directly convert corn stover (stalks and leaves of corn) into 5-hydroxymethyl-fufural (HMF) by using N,N-dimethylacetamide (DMA) (containing lithium chloride as solvent and chromium catalyst). The chloride ions dissolve and break up interactions between the cellulose molecules.

Image (X) shows this conversion. HMF can be easily changes into a potential bio-fuel: dimethylfuran (DMF). DMF has 40% higher energy content than ethanol, which means it has the same energy content as gasoline. It has been

Raines-biofuels-paper-400_tcm18-144094.jpg
Image (X) : <http://www.rsc.org/chemistryworld/News/2009/February/11020901.asp>

proven to be an effective fuel additive. Gasoline has high energy because of its high carbon content (more carbons able to combust), so to make a good fuel out of cellulose (structure of cell walls), we must try to make the bio-fuel a high carbon content. To do this, the oxygen must be removed from the molecule. As the cellulose breaks down, the 3 hydroxyl groups become water molecules, also hydrogen gas is added to remove more oxygens (create more water molecules) and so the HMF is reduced into DMF.

The University of Wisconsin-Madison team was

able to produce a yield of over 50% using this process.

This organic chemistry approach is thought to be a much more efficient than the fermentation in mass production of fuels. DMF is not yet a perfect, suitable fuel, but this is a major step in the direction of creating a more efficient process of fuel production.


Coffee as a Bio-diesel

At the university of Nevada Dr. Mirsa started to research using coffee as a biofuel. He thought of this after he found an oil on top of his coffee after leaving it over night. He looked into this further and found out that coffee was an excellent biofuel because it burns clean, is less thick, doesn’t have a bad smell, and burned in an engine with little or no tinkering. 1 litre of biodiesel requires 5-7 kg of coffee grounds, it costs around 1$ per gallon.

How it’s made:
To make coffee into a biofuel you need to dry the coffee grounds and add a chemical like hexane, ether and dichloromethane so that they dissolve the oils in the coffee. Then the grounds and the chemicals are separated because they can be re-used. Then the biofuel is heated to remove any water, then add a catalyst and methanol so that transesterification can happen. After it cools the biofuel floats to the top and the glycerine sinks to the bottom.


How Biodiesel is Made

Step 1: Titration

This is the method of determining how much catalyst is needed to neutralize the fatty acids in the used vegetable oil

Titration Equation

7.0 g KOH + L = X

Where L is the number of grams of KOH necessary to neutralize and react one liter of used vegetable oil and X the number of milliliters of KOH/water solution dropped into the oil alcohol mixture

Step 2: Measure the Reactants

  • Vegetable oil
  • Rubbing Alcohol
  • Methanol
  • Potassium hydroxide
  • Distilled water
Step 3: Dissolve the KOH in the Methanol

Step 4: Mix the Reactants

Step 5: Allow the Glycerin to Settle




475px-Transesterification_of_triglycerides_with_ethanol.png
http://en.wikipedia.org/wiki/Biodiesel_production

This shows triglycerides react with an alcohol such as ethanol and produces ethyl esters and glycerol.




Generic_Biodiesel_Reaction1.gif
http://en.wikipedia.org/wiki/Biodiesel_production



This shows the reaction of Triglyceride and Methanol reacting to produce Glycerol and Methyl Esters. This is a transesterification reaction.



Biodiesel_Reaction2.gif
http://en.wikipedia.org/wiki/Biodiesel_production



This shows another reaction like the one above but this one creates multiple methyl esters.


When the esterification process is happening, you need the triglyceride to react with alcohol and a catalyst. A reason for doing a titration to produce biodiesel, is to figure out how much alkaline is requires to neutralize free fatty acids, to make sure a complete transesterification happens. This reaction happens when the alcohol reacts with the fatty acids to make the biodiesel and crude glycerol. This reaction can be reversed so alcohol must be steadily added to make sure the reaction goes right and to make sure the complete change.



References