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Why can’t we make Biodiesel from algae at home. It will be bit costlier process, but if we tie up with bigger companies, who gives subsidy for production.
A common method of obtaining pure cultures is serial dilution. Cultivators dilute a wild sample or a lab sample containing the desired algae with filtered water and introduce small aliquots into a large number of small growing containers. Dilution follows a microscopic examination of the source culture that predicts that a few of the growing containers contain a single cell of the desired species. Following a suitable period on a light table, cultivators again use the microscope to identify containers to start larger cultures.
Alternatively, mixed algae cultures can work well for larval mollusks. First, the cultivator filters the sea water to remove algae which are too large for the larvae to eat. Next, the cultivator adds nutrients and possibly aerates the result. After one or two days in a greenhouse or outdoors, the resulting thin soup of mixed algae is ready for the larvae. An advantage of this method is low maintenance.
Water, carbon dioxide, minerals and light are all important factors in cultivation, and different algae have different requirements. The basic reaction in water is carbon dioxide + light energy = glucose + oxygen.
The water must be in a temperature range that will support the specific algal species being grown.
Light and mixing
In most algal-cultivation systems, light only penetrates the top 3 to 4 inches (76–100 mm) of the water. As the algae grow and multiply, the culture becomes so dense that it blocks light from reaching deeper into the water. Direct sunlight is too strong for most algae, which need only about 1/10 the amount of light they receive from direct sunlight.
To use deeper ponds, growers agitate the water, circulating the algae so that it does not remain on the surface. Paddle wheels can stir the water and compressed air coming from the bottom lifts algae from the lower regions. Agitation also helps prevent over-exposure to the sun.
Another means of supplying light is to place the light in the system. Glow plates made from sheets of plastic or glass and placed within the tank offer precise control over light intensity.
Odor and oxygen
The odor associated with bogs, swamps, indeed any stagnant waters, can be due to oxygen depletion caused by the decay of deceased algal blooms. Under anoxic conditions, the bacteria inhabiting algae cultures break down the organic material and produce hydrogen sulfide and ammonia which causes the odor. This hypoxia often results in the death of aquatic animals. In a system where algae is intentionally cultivated, maintained, and harvested, neither eutrophication nor hypoxia are likely to occur.
Nutrients such as nitrogen (N), phosphorus (P), and potassium (K) can serve as fertilizer for algae. Silica and iron, as well as several trace elements, may also be considered important marine nutrients as the lack of one can limit the growth of, or productivity in, a given area.
Pond and bioreactor cultivation methods
Algae can be cultured in open-ponds (such as raceway-type ponds and lakes) and photobioreactors. Raceway ponds may be less expensive.
Raceway-type ponds and lakes are open to the elements. Open ponds are highly vulnerable to contamination by other microorganisms, such as other algal species or bacteria. Thus cultivators usually choose closed systems for monocultures. Open systems also do not offer control over temperature and lighting. The growing season is largely dependent on location and, aside from tropical areas, is limited to the warmer months.
Open pond systems are cheaper to construct, at the minimum requiring only a trench or pond. Large ponds have the largest production capacities relative to other systems of comparable cost. Also, open pond cultivation can exploit unusual conditions that suit only specific algae. For instance, Spirulina sp. thrives in water with a high concentration of sodium bicarbonate and Dunaliella salina grow in extremely salty water. Open culture can also work if there is a system of culling the desired algae and inoculating new ponds with a high starting concentration of the desired algae.
Some chain diatoms fall into this category since they can be filtered from a stream of water flowing through an outflow pipe. A “pillow case” of a fine mesh cloth is tied over the outflow pipe allowing other algae to escape. The chain diatoms are held in the bag and feed shrimp larvae (in Eastern hatcheries) and inoculate new tanks or ponds.
Enclosing a pond with a transparent or translucent barrier effectively turns it into a greenhouse. This solves many of the problems associated with an open system. It allows more species to be grown; it allows the species that are being grown to stay dominant; and it extends the growing season – and if heated the pond can produce year round.
Algae can also be grown in a photobioreactor (PBR). A PBR is a bioreactor which incorporates a light source. Virtually any translucent container could be called a PBR, however the term is more commonly used to define a closed system, as opposed to an open tank or pond.
Because PBR systems are closed, the cultivator must provide all nutrients, including CO2.
A PBR can operate in “batch mode”, which involves restocking the reactor after each harvest, but it is also possible to grow and harvest continuously. Continuous operation requires precise control of all elements to prevent immediate collapse. The grower provides sterilized water, nutrients, air, and carbon dioxide at the correct rates. This allows the reactor to operate for long periods. An advantage is that algae that grows in the “log phase” is generally of higher nutrient content than old “senescent” algae. Maximum productivity occurs when the “exchange rate” (time to exchange one volume of liquid) is equal to the “doubling time” (in mass or volume) of the algae.
Different types of PBRs include:
* Polyethylene sleeves or bags
* Glass or plastic tubes.
With the current prices of oil going up in the Middle East, the constant rallying of the environmentalist to save and protect our planet and the constant clamor of people around the world to find ways to have an alternative sources of fuel. To alleviate the every rising cost of fuel in the world market, scientist and inventors are finding ways to provide and develop alternative fuel that can be beneficial for everyone, and one of this through the use of Algae biodiesel.
Why algae? Kerogen is the primary source of petroleum, with the right temperature kerogens can be turned into oily substances under the ground which are now being mined as petroleum. Kerogen is formed from the following matters algae, biodegraded organic compounds, plankton, bacteria, plant material, to name a few. And through this findings scientist has made several studies to replicate the actual process of this elements to produce petroleum in a controlled environment such the diagenesis and catagenesis. It is found that algae grown in CO2 enriched environment can be converted to algae biofuels. This is good news because you eliminate 2 major problems at the same time. In order to produce oil from algae it has to grow on a CO2 enriched environment meaning you can be able to rid of air pollution and at the same time provide algae biofuels to ease the burden of high gasoline cost.
Algae biofuels have the same chemical composition and burning capacity as of fossil fuel. And so far this are the benefits that they are found out in the use of biodiesel. So that it can be a better alternative fuel in the future. The benefits of using algae biofuels are:
1. Algae biofuelsbiodegradable, it does not pose harm in the environment unlike the commercial diesel oils which emits carbon dioxide in the environment.
2. It is non-toxic it has no lead content and sulphur and other additives or aromatics that are added on the fuel.
3. It can be used by any diesel based engine.
4. Improve lubrication in the engine for smooth engine run.
5. High octane number. Meaning there is a great burning capacity for better engine torque and performance.
6. Improved conductivity of the car compared to the commercially produced diesel fuel.
The best advantage of algae biodiesel is that it is a renewable source of energy. Algae abundantly grow in all conditions that are favorable to its synthesis and propagation. Though this technology has its own merits the manufacturer of this technology hasn’t perfected this technology yet. Although the potential are there and the possibilities are right in their hands there are many things that has to be considered in order for algae biodiesel to go mainstream. Like mass production, extraction of water in algae and oil, and all of the engines and parts that are manufactured nowadays are made using the petroleum based fuels. Reverting to biodiesel the neat petrol will however affect the performance of the engine parts. Though biodiesel will make the car run but the capacity of the engine to burn natural gas still remains under research and study. The Department of Energy is constantly doing research to improve the usage of algae as alternative for the ever increasing fuel in the world market.
Algae Oil Extraction
The race to produce a lower cost of biodiesel to replace fossil fuel are on the rise. This mainly due to over mining of fossil fuels that will not last if we keep on extracting them, due to the increase of price of crude oil in the world market today, that affects the prices of prime commodities life food and fuels. Since then scientist have been researching to find ways to have a fuel that could be of equal standards of fossil fuels. And there are a number of sources that are found to be a viable source of energy there is corn, soya, palm oil, and waste oil. All of these has a great potential to be a source of biodiesel but there is one organism that are found to have a greater potential to produce more oils than crop based oils which in turn can have a great effect on food production in the long run and this is algae oil.
Many big companies are also in search to have an alternative way to lower the cost of gasoline. They are teaming up with startup companies to fund their research on finding the right strain of algae that can be harvested to produce more oils to meet the demands of the world market for oil. The United States Department of Energy has been on its feet in developing algae for this alternative biodiesel. In fact one of its department has partnered with chevron one of the number players and importer of fuels in the world have team up with the National Renewable Energy Laboratories to find ways to mass produce biodiesel from algae. Besides finding way on how to mass produce and process the oils from algae another obstacle for scientist is the extraction of algae oil in the process. There are numerous ways of algae oil extraction and they are:
1. Expeller/Press – a tried and tested method of extraction. By letting the algae dry out and then pressed to extract the oil
2. Hexane Solvent Method – this makes use of a chemical hexane that can be mixed with the algae. Then using the expeller is pressed to extract the oils from the algae then it can undergo another extraction because of the hexane. Hexane are then separated through distillation. Much yield could be produce in this method. What’s more hexane is inexpensive.
3. Supercritical Fluid Extraction – this is the most viable way of extracting 100% oil from the algae the only downside of this process is the need for a special machinery and equipment for extraction. It liquefies the carbon dioxide under pressure and heated until that both elements are in its liquid state and gas. These liquids acts as a solvent to extract the oils from the algae’s.
4. Ultrasonic-assisted extraction –as the name implies it makes use of ultrasonic devices to extract oils from algae’s. In this process ultrasonic waves are being sent around the algae’s sending shock signals on to the organism as a reaction to the wave they release oil substances onto the solvent that can now be easily extracted.
These kinds of processes is too expensive for a startup company that is why many companies that grows algae’s are teaming up with oil company giants because they have the capabilities to provide such kinds of process of extraction. Biodiesel from algae has a great potential but we still have to wait a little longer for its release to the public there is still much to be done and studied the public may have to tighten their belt a little while.