Biodiesel is an alternative fuel, quite similar to the conventional fossil diesel, which is produced from an increasingly diverse mix of sources such as recycled cooking oil, soybean oil, or vegetable and animal fats. Unlike conventional diesel, biodiesel is renewable, clean, and a biodegradable alternative. It meets both the biomass-based diesel and the overall advanced biofuel requirements of the Renewable Fuel Standard. Calling biodiesel an alternative means it can be used in place of the conventional fossil diesel, in engines without modification
Created by chemically treating vegetable oil or animal fat with alcohol generating compounds, biodiesel is the revolution that is helping several countries overcome their dependence on diesel. It can be operated in any diesel engine with little or no modification to the engine or the fuel system.
In other words, biodiesel is domestically produced, clean-burning fuel that can be produced from waste vegetable oils, animal fats, or recycled restaurant grease for use in diesel vehicles. It is biodegradable, less toxic and produces fewer pollutants when burnt completely. It can be used in pure form (B100) or blended with petroleum diesel. Most of the common blend include B2 (20% biodiesel, 80% petrodiesel), B5 (5% biodiesel, 95% petrodiesel) or B20 (20% biodiesel, 80% petrodiesel).
Biodiesel exists in a liquid form and is often referred to as B100 or neat biodiesel in its pure and unblended form. Its performance in cold weather is dependent on its blend, the feedstock and the petroleum diesel characteristics. Generally, blends with smaller percentages of biodiesel perform better in cold weather.
However, fuel-grade biodiesel has to be produced in accordance with strict industry specifications, to ensure its proper performance. As raw vegetable oil does not meet these biodiesel fuel specifications, it cannot be considered biodiesel, on its own.
Biodiesel is made through a process known as transesterification, which converts these oils to biodiesel. The process will be discussed below. The largest possible source of suitable oil comes from oil crops such as rapeseed, palm or soybean. Most contemporary biodiesel is produced from waste vegetable oil sourced from restaurants, chip shops, and industrial food producers.
Such waste vegetable oil is often sourced for free or for a small price. Oil straight from the agricultural industry could represent the greatest potential source but unfortunately is not produced commercially as the raw oil is too expensive. Insisting on such fuel will mean a product that is too expensive than the common fossil diesel
How to Make Biodiesel? (Process of Making Biodiesel)
1. Collecting the oil
Oil is the main ingredient in biodiesel and comes from various sources. You can use waste vegetable oil, collected from restaurants, for little to no cost. It can also come from certain field crops like soybeans and canola. Oil can be extracted from these and more field crops in various ways, depending on the crop itself.
The most common method is cold pressing where cold press extruders extract the oil. The seeds are put under immense amounts of pressure which eventually squeezes the oil out. The remaining part, also known as a meal, can be used as a protein source for livestock feed.
2. Cleaning the oil
Before using the oil as a biofuel, it needs to be thoroughly cleaned. Filter out the solid particles and water from the waste vegetable oil and crushing, to make the resulting biodiesel to be of high quality. Some other chemicals and physical processes can also be used to help out int eh removal, although the most common is head-space desiccation.
3. Adjust the oil’s pH
Use titration to ensure only the correct amount of catalyst is added to the reaction, allowing all the triglycerides in the oil are converted into biodiesel. Using data from the titration procedure, mix ethanol and catalyst and this methoxide mix will go into the smaller cone bottom tank to be injected into the reactor tank.
This is the process that converts vegetable oil into biodiesel. During the procedure, the oil which is predominantly made up of triglycerides is split into glycerol and fatty acid ethers or biodiesel, through the use of alcohol, typically methanol. The reactor tank will then heat the oil to 120˚F and circulate the oil and methoxide for about two hours.
5. Washing and cleaning
Once the oil is converted into biodiesel, separate the glycerine from the mixture. Glycerine is a by-product of the aforementioned transesterification process, but is of low value, making it lack value. It is therefore commonly disregarded unless the process is large scale. The easiest way to separate them is to use gravity as glycerine settles and can be drawn off the bottom of the reactor tank.
Any excess methanol and catalyst can be removed by cleaning the product with water. Wash the product twice, circulate the biodiesel by heating it to about 90˚F for about 1.5-2 hours until the biodiesel is clear and all the water has evaporated. Dry solids like sawdust can also achieve the same result as water, although they must be filtered out before the biodiesel is used
6. Quality testing
This is the final process and is crucial to test the quality of the biodiesel before it is used. If too much water was used or is still present in the fuel, it will be a source of impurities. The impurities could also come from the incomplete conversion of oil into biodiesel.
There are kits available to test for all of the characteristics of biodiesel and they should be used for each batch. If biodiesel is to be burned in cold temperatures, you still have to test for cloud point and mix with petroleum diesel at no more than a 5% rate.
7. Making biodiesel at home
It is also possible to produce biodiesel at home, with only about a litre of vegetable oil, at least 6g of sodium hydroxide, lye or caustic soda, which is mainly used as a drain cleaner, and at least 250ml of methanol which is used as an antifreeze. The procedure might be a little different but the processes are the same. You will make the methoxide by mixing the methanol and NaOH (CAUTION: this is very dangerous as the methoxide is highly toxic), make the biodiesel, wash it and then dry it. This process is explained here
Various Differences Between Biodiesel and Diesel
Petroleum diesel is obtained from the fractional distillation of crude oil. The crude oil is mined below the surface of the earth and then distilled until diesel is obtained. On the other hand, biodiesel is obtained through the transesterification process, which converts oils into biodiesel. Such oils are obtained from oil crops like rapeseed, palm or soybean. Most contemporary biodiesel is produced from waste vegetable oil sourced from restaurants, chip shops, and industrial food producers.
Biodiesel has higher lubricity, meaning it is more slippery than petroleum diesel. This makes it ideal for use as it can reduce engine wear. It, therefore, follows that petroleum diesel is less slippery and could result in engine wear over time
3. Presence of sulfur
Biodiesel, practically contains no sulfur, primarily because of how it is made. The absence of sulfur in biodiesel makes it safer for the environment as it reduces pollution, or at least does not emit the harmful gases and particles that pollute the environment
4. Relationship with the environment
Biodiesel is renewable, clean, and a biodegradable alternative to petroleum diesel. Petroleum diesel, once used up in an engine, releases carbon gases as well as other harmful gases which not only cause a warming effect on the atmosphere but also adversely affect the environment. Biodiesel, on the other hand, is safer and can safely be used without harming the environment.
5. Presence of oxygen
Biodiesel has a higher oxygen content as compared to fossil diesel, of up to between 10% and 12%. Because of this, any engine that runs on biodiesel will release fewer pollutants or emissions. Unfortunately, in comparison to petroleum diesel, a biodiesel-powered engine has a lower or reduced peak engine power by about 4%.
6. Toxicity levels
Biodiesel is much less toxic than petroleum diesel. This makes it ideal for spill clean-ups as explained above.
7. Oxidation levels
Biodiesel is more likely to react with oxygen, forming a semisolid gel-like mass. It is a particular concern especially for extended fuel storage and when using engines that are only operated occasionally, like standby generators. Therefore, to properly store biodiesel, use a dry, semi-sealed, cool, and light-tight container.
8. Behaviour in cold temperatures
Biodiesel tends to thicken and gel-up especially in low temperatures. It presents a particular type of problem in comparison to petroleum diesel and is a concern especially for cold winters and temperatures.
Petroleum diesel is extracted through the fractional distillation of crude oil, meaning it is uniform and reliable. On the other hand, biodiesel can be generated from various sources, such as waste recycled cooking oil, soybean oil, or vegetable and animal fats. This means biodiesel comes in various qualities with some being not so good.
Various Uses of Biodiesel
The primary reason for making biodiesel is to have a renewable, clean, and biodegradable alternative to conventional fossil diesel. This means it will primarily be used in the transportation industry. The transportation industry is responsible for 24% of energy and over 60% of absorbed oil all over the world, with more than 30% of the energy consumed in the US alone. This means that over a third of the oil in the world is used to operate vehicles. Biodiesel is therefore an improvement in the industry as it is a renewable alternative to fossil diesel.
2. Generating energy and electricity
Biodiesel can also be used to generate power in backup systems where emissions matter most, like schools, hospitals and residential areas. Biodiesel will therefore be an addition to the fuel cells that have a power-generating application, available for electricity.
Consumers can also use biodiesel in place of batteries to charge and power electric devices such as computers and cell phones. Such cells are still in development but have the potential to become a steady source of power.
3. Providing heat
Over the last few years, the concept of bioheat has continued to grow. It relies on using biofuel such as biodiesel, being used as a source of heating. It replaces wood, which is the most practical heating method.
A blend of biodiesel for heating can also reduce the emission of both sulfur dioxide and nitrogen. This heat can also be used in cooking, replacing kerosene which is primarily used in stoves and non-wick lanterns.
4. Cleaning oil spills
Biofuel is environmentally-friendly and can therefore be used to clean up oil spills and grease. It has been tested to work as a potential cleaning agent for areas where crude oil contaminates the water. The results have also been found to increase the recovery areas and allow it to be removed from the water even if biodiesel is spilled or released into the environment, it causes far less damage than fossil diesel, as it is less combustible. It is safe to handle, store, and transport, making it ideal for cleaning oil spills
Biodiesel is vital in vehicle engines as it reduces the sulfur concentration, where sulfur provides the most lubricity of the fuel. As such, biodiesel keeps the engine functioning properly and avoids premature infection failure
Benefits of Biodiesel fuel
Biodiesel is made from renewable resources mainly from agricultural co-products and byproducts such as soybean oil, other natural oils, and greases and thereby is a solution for our green concerns. The emissions are lower as compared to those from diesel (petroleum). A detailed explanation would state that biodiesel, reduces unburned hydrocarbons, particulate matter and other gases as compared to petroleum diesel. In the United States of America, it is produced on a large scale in a bid to reduce dependency on other countries for oil needs. This had led to several green jobs being created and has also contributed to the economy.
It produces less carbon output and fewer pollutants than traditional petroleum products. When compared to petroleum diesel, biodiesel produces less soot (particulate matter), carbon monoxide, unburned hydrocarbons, and sulfur dioxide. Pollution from oil causes more air pollution and many people fall sick every day. With the use of biodiesel, people have got huge health benefits as they need to spend less money on healthcare products.
As more crops are grown to produce biodiesel, it has created vast employment opportunities. Local people are employed in biofuel production plants and an increase in demand for biodiesel may create more jobs. People who create crops to be used in biodiesel enjoy benefits as an increase in demand for biodiesel leads to an increase in demand for suitable biofuel crops.
The last few years have seen the upsurge of several vehicles and machines, with engines that run on biodiesel. One constantly hears and reads about the same in newspapers and automobile magazines. A large number of vehicles in the United States of America, come with options of biodiesel engines, talking volumes about the boom of this technology.
Biodegradation rates of biodiesel is another area of discussion. It degrades much faster than petrol and diesel. The area of concern with the generation of biodiesel is a rut in the agricultural patterns for rearing biodiesel crops. The monotonous growth of the same crop will affect the ecology and the quality of the land.
The debate on biofuels still on and its effects are still being accessed. But that does not dampen the ambitions of Biodiesel. Biodiesel is fast catching up in other countries too, as they snowball into an economically competitive alternative for energy. With Biodiesel making it big, the companies that manufacture it are acting increasingly as power companies. With the sky-rocketing prices of oil and petroleum, several investors are moving towards investing in Biofuels citing greener pastures and a better future on this side.