|
Cultivation of Algae Strains for Biodiesel
From Oilgae.com – Oil from Algae (So what’s the Oilgae story?)
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|
Nature gave us oil from algae; perhaps we should try Nature’s way again
You are at: Oilgae Home > About Algae > Algae Oil > Biodiesel from Algae Oil > Algae Cultivation for Biodiesel
Oilgae Highlights
Notes:
See also: For all aspects of Biodiesel production, uses, research and case studies, please refer to our Biodiesel Section @ Oilgae Energy Portal
! Are you an inventor or equipment producer for fuel from algae, or part of a company that is involved in the algal fuel efforts? Please see this section in order that you can help us list your company or efforts @ Oilgae
Cultivation of Algae Strains for Biodiesel
Like plants, algae require primarily three components to grow: sunlight, carbon-di-oxide & water. Like plants again, they use the sunlight for the process of photosynthesis. Photosynthesis is an important biochemical process in which plants, algae, and some bacteria convert the energy of sunlight to chemical energy. This chemical energy is used to drive chemical reactions such as the formation of sugars or the fixation of nitrogen into amino acids, the building blocks for protein synthesis. (see Photosynthesis – from Wikipedia). Algae capture light energy through photosynthesis and convert inorganic substances into simple sugars using the captured energy.
Finding algea strains to grow isn't too difficult. Cultivating specific strains of algae for biodiesel could be however a bit more difficult, as they can require high maintenance and could get easily contaminated by undesirable species.
Since algae need for their growth sunlight, carbon-di-oxide and water, they can be cultivated in open ponds & lakes. Due to the fact that these systems are "open", they are much more vulnerable to being contaminated by other algal species and bacteria. The real challenge with open air bioreactors (like a pond) is that the species of algae that have the highest oil content are not necessarily the quickest to reproduce. This creates a problem where other species take over the pond. Undesirable algal species taking over specific strains is one of the more significant problems in algaculture, For this reason, the number of species that have been successfully cultivated for a given purpose in an open system is relatively small. In addition, in open systems there is relatively less control over water temperature, carbon-di-oxide concentration & lighting conditions. These imply that the growing season is largely dependent on location and, aside from tropical areas, is limited to the warmer months. While the above are the disadvantages with “open systems”, some of the benefits of this type of system are that it is one of the cheaper ones to produce - at the most basic you only need to dig a trench or pond.
A variation on the basic "open-pond" system is to close it off, to cover a pond or pool with a greenhouse. While this usually results in a smaller system, it does take care of many of the problems associated with an open system. It allows more species to be able to be grown, it allows the species that are being grown to stay dominant, and it extends the growing season, only slightly if unheated, and if heated it can produce year round. It is also possible to increase the amount of carbon-di-oxide in these quasi-closed systems, thus again increasing the rate of growth of algae.
The ponds in which the algae are cultivated are usually what are called the “raceway ponds”. In these ponds, tha algae, water & nutrients circulate around a racetrack. With paddlewheels providing the flow, algae are kept suspended in the water, and are circulated back to the surface on a regular frequency. The ponds are usually kept shallow because the algae need to be exposed to sunlight, and sunlight can only penetrate the pond water to a limited depth. The ponds are operated in a continuous manner, with CO2 and nutrients being constantly fed to the ponds, while algae-containing water is removed at the other end.
Alternatively, algae could be grown in closed structures called photobioreactors, where the environment is better controlled than in open ponds. While the costs of setting up and operating a photobioreactor would be higher than for those for open ponds, the efficiency and higher oil yields from these photobioreactors could be significantly higher as well, thus offsetting the initial cost disadvantage in the medium and long run.
Photobioreactors
A photobioreactor is an equipment that is used to harvest algae. A photobioreactor is basically a bioreactor that incorporates some type of light source. The term photobioreactor is more commonly used to define a closed system, as opposed to an open pond. A pond covered with a greenhouse could also be considered a photobioreactor. Because these systems are closed everything that the algae need to grow, (carbon dioxide, water and light) need to be introduced into the system.
Photobioreactors can be set up to be continually harvested (the majority of the larger cultivation systems), or by harvesting a batch at a time (like polyethlyene bag cultivation). A batch photobioreactor is set up with nutrients and algal seed, and allowed to grow until the batch is harvested. A continuous photobioreactor is harvested either continually, as daily, or more frequently.
Some types of photobioreactors include: · glass or plastic tubes · tanks · plastic sleeves or bags
Growing algae at home
Take a container and add a small amount of algae culture. If your plans for growing algae are towards producing biodiesel feedstock, you will need to find specific algae strains. Adding an aquarium bubble stone increases growth and circulates the algae. The only requirements for this type of system are CO2, (ambient CO2 is sufficient, though you're growth rate will be slower), nutrients, such as fertilizer or manure, and a light source. The optimal temperature range will depend on the strain you are using.
Some questions found at a message board re growing algae at home: Is it possible to grow the required algae on a small scale? How much know-how do you need? How high are the initial costs? Would growing algae be very complicated? Could they even grow it indoors?..Do you know of any websites that give instructions for do-it-yourself biodiesel (or even ethanol?)...
See also: Can Oil-producing Algae be Grown at Home? – Biodiesel Now Forum, In-home Photosynthetic Bio-reactor Lighting
Some sources that can be used to provide the light energy required to sustain photosynthesis include
· Fluorescent bulbs · LEDs, or · Natural sunlight
Some more thoughts on algae growth and cultivation
· It could also be worth thinking about how (or if) marine algae could be grown – perhaps through iron fertilization - in otherwise unproductive (high-nitrogen-low-chlorophyll) regions of the open oceans.
Research on Algae Cultivation
· The NREL (national Renewable Energy Laboratory, part of the Department of Energy) conducted research into algae production. NREL favoured unlined “raceway” ponds which were stirred using a paddle wheel, and had carbon dioxide bubbled through it. The water used for these ponds is wastewater (treated sewerage) freshwater, brackish water, or salt water, depending on the strain of algae grown. The algae should be a native to the region. · Other countries, notably Japan, are interested in closed systems; however these systems (at least from NREL perspective) are very expensive.
Related Links:
The Existing Large-scale Natural Sources for Biodiesel
The existing large-scale natural sources are of algae are:
Terrestrial & Aquatic Plants
Bogs, marshes & swamps - Salt marshes and salt lakes Swamps & marshes fall into two categories; forested swamps and shrub swamps. Forested swamps are dominated by specific types of trees. They also have other varieties of trees and plants. A shrub swamp has mostly shrubs in it rather than trees. It is the shrub swamp that is usually dominated by algae, apart from grass, reeds, and many types of shrubs.
Sewages & Garbage
Farm Dams & Large Water Reservoirs
Hot springs
Rivers, Lagoons, Lakes & Ponds, Puddles etc. – also Saline Lagoons, Saline Lakes & Marshes
Snow, Soil, Mud, Sand & Rocks (internal & and on surface)
Purchasing Algal Strains for Biodiesel
Some web resources on algal cultures availability for purchase, includes international organizations involved in culture collections:
More articles & news on algae cultivation for biodiesel: Visitors may kindly have a look at the Oilgae Blog Directory for relevant blog articles.
Oilgae.com Main Sections
Algal Oil Related
About Algae > Where do Algae Grow, Algae Composition, Algae Left-over Extract
Algae Oil > Oil Yield from Algae, Algal Oil Extraction
Biodiesel from Algae Oil > Algae Cultivation for Biodiesel, Biodiesel Production from Algal Oil, Algae Biodiesel Properties, Large-scale Algae Biodiesel Production, Algae Biodiesel Reference, Algae Biodiesel News, Algae Biodiesel Research, Algae Biodiesel - Companies
Energy & Alternative Energy
Energy Portal – Discussed topics such as alternative & renewable energy, peak oil, energy industry inventions & discoveries, and more.
Check out the latest inventions and breakthroughs in energy & alternative energy, on the following topics @ NewNergy Blog
Add Links/Submit Links: Do you have a web resource that belongs to here? If you have a web site that you wish to include in this page, do let us know the details by sending a note about your URL to [narsi]@[esource].[in] to add URL (pl remove the [ ] to get my email address!). We’ll quickly review the web site, and if found relevant, add it to the database. Thanks!
Oilgae.com content is available under GNU Free Documentation License: All content at Oilgae.com is licensed under the GNU Free Documentation (GFDL). Put simply, under this license, anyone is free to copy & use any amount of content @ Oilgae.com, make changes to it and use it in any way they wish, as long as they also allow the same rights to anyone else for this content. To those who wish to use content from Oilgae.com, our only request is that they acknowledge the source and provide a link back to Oilgae.com. Put not so simply, see the Oilgae.com GNU Free Documentation License .
Some interesting resources
Agriculture Directories
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
