How about a green substitute to black gold?

Researchers world over are looking for an alternative source of fuel, which is efficient, environment-friendly and recyclable.

There are many different types of these ‘green’ fuels; composed of different mixtures. Biodiesel is one among many in which animal oil fats, greases and feed stock are used.

There are many plants like jatropha, honge and local palm which contain good percentage of oil and can be easily used in motor vehicles. For example, ethanol, available in pure form, can be made from sugar plant, corn and sorghum. In the United States, ethanol is mixed with gasoline in different proportions (10 to 85 per cent).

State-run buses in Karnataka use ethanol and honge oil mixed with diesel. Cellulosic ethanol or lignocelluloses made of a mass of plants, dried corn stalks and leaves, grasses and wood chips.

The focus is now on algae oil. This is presumed to be the perfect green fuel source. It should be noted that micro algae is used for this purpose as it contains high amount of required fat oils called triaglycerols and not ordinary sea weed which is a macro algae. This product is also called ‘oilgae’ and seems to be the ideal replacement for petrol and diesel without changing the engine.

High yield

Unlike other food crop like corn which requires lots of water, fertiliser and land to grow, algae needs very little space and clean seawater. Its simple structure allows for easier conversion into biodiesel and has a very small carbon footprint. Global warming’s primary gas, carbon dioxide, nourishes algae. When compared to most other biodiesel, algae yields very high energy. Research has begun to develop algae oil to substitute jet fuels too.

Cultivated and harvested algae is squeezed to obtain oil. The residual matter can be used as animal feed or for other high value products. To make biodiesel, algae oil is treated with sodium ethnolate and ethanol in a process called ‘transestrification’. Algal lipids are then turned into biodiesel and non fuel residue.

Pond algae is said to be best suited for biodiesel. This algae, during photosynthesis, absorbs CO2 from the air and replaces it  with Oxygen (O2). This property makes this biofuel sought after by manufacturers and environmentalists. According to one estimate, 100,000 gallons of algae oil per acre can be produced without disturbing the growth of the feedstock. Many experts say over 140 billion gallons of algal biodiesel is required to replace the petrol based products every year. To reach this goal only about 100 million acres of land is necessary as algae can be grown both outdoors and indoors.

Simple extraction

The process of extracting the oil is as simple as squeezing an orange. The oil press is the simplest and most popular method. With this, up to 75 per cent of the oil can be extracted. It’s a two-part process. The press squeezes the oil and the left over algae is mixed with hexane and cleaned so no chemical is left over.

Another method is the supercritical fluid method. Here carbon dioxide acts as a super critical fluid. When a substance is pressurised and heated its composition changes to liquid and gas. The carbon dioxide is mixed with algae, completely converting it to oil.

Once the oil is extracted, it is refined using the fatty chain – a process called transestrification. A catalyst like sodium hydroxide (NaOH) is mixed with alcohol (methanol) which makes the biodiesel fuel combine with glycerol. This is refined to remove the glycerol. The final product is algae biodiesel. In this process almost 100 per cent of the oil can be extracted.

While micro algae has all these advantages, the disadvantages must also be looked into. The negative effects of releasing more oxygen into the air must also be studied.