31-01-2013, 10:22 AM
Biodiesel from Algae oil
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What are Algae?
Algae range from small, single-celled organisms to multi-cellular organisms, some with fairly complex and differentiated form. Algae are usually found in damp places or bodies of water and thus are common in terrestrial as well as aquatic environments. Like plants, algae require primarily three components to grow: sunlight, carbon-dioxide and water. Photosynthesis is an important bio-chemical process in which plants, algae, and some bacteria convert the energy of sunlight to chemical energy.
The existing large-scale natural sources are of algae are: bogs, marshes and swamps - salt marshes and salt lakes. Micro-algae contain lipids and fatty acids as membrane components, storage products, metabolites and sources of energy. Algae contain anything between 2% and 40% of lipids/oils by weight.
How to harvest Algae?
The photo-bioreactor is the main equipment used to harvest algae. Photo-bioreactors can be set up to be continually harvested (like the majority of the larger cultivation systems), or by harvesting a batch at a time (like polyethylene bag cultivation). A batch photo-bioreactor is set up with nutrients and algal seed, and allowed to grow until the batch is harvested. A continuous photo-bioreactor is harvested, either continually, as daily, or more frequently.
Challenges in Algaculture
According to an article published in May 2007 by the Nature magazine [19], Algae can also be picky: too much direct sunlight can kill them, temperature must be held steady, overcrowding will inhibit their growth, the ―waste‖ oxygen they produce must be continually removed from the water, open algal ponds are subject to evaporation and rainfall, which cause salinity and pH imbalances, and local species of algae often overgrow the desired strain.
Algaculture for Biodiesel production
Algal-oil processes into biodiesel as easily as oil derived from land-based crops. The difficulties in efficient biodiesel production from algae lie not in the extraction of the oil, but in finding an algal strain with a high lipid content and fast growth rate that isn't too difficult to harvest, and a cost-effective cultivation system (i.e. type of photo-bioreactor) that is best suited to that strain.
Micro-algae have much faster growth-rates than terrestrial crops. The per unit area yield of oil from algae is estimated to be from between 5,000 to 20,000 gallons (18,927 to 75,708 litres) per acre, per year; this is 7 to 31 times greater than the next best crop, palm oil (635 gallons or 2,404 litres).
The production of algae to harvest oil for biodiesel has not yet been undertaken on a commercial scale, but feasibility studies have been conducted to arrive at the above yield estimate. In addition to its projected high yield, algaculture — unlike crop-based biofuels — does not entail a decrease in food production, since it requires neither farmland nor fresh water. Many companies are pursuing the development of algae bioreactors for various purposes – including biodiesel production and CO2 capturing.
Patents in the Algae oil sector
There are a number of patents of photo-bioreactor and algae pond layouts as well as optimization processes, but the procedure of production biodiesel from Algae oil is fairly simply. We can predict that more photo-bioreactor, pond layouts as well as new processes of production will emerge as more R&D is being conducted. At present most companies in the sector are early stage start-ups and involved in R&D rather than commercialisation. To date, none has launched full commercialisation/industrialization of biodiesel from Algae oil on a large scale. Patents could prove to be play important factor in the future, especially when companies start raising money from venture capital (VC) firms which tend look at intellectual property as well as technological know-how and expertise.