Production of Biofuel from Algae

Summary: Fuel crises increases in the world day by day, so the need and demand of economical fuel also increases. About 9.3 billion gallons of biodiesel are consu

Project Title

Production of Biofuel from Algae

Project Area of Specialization

Biomedical Engineering

Project Summary

Summary:

Fuel crises increases in the world day by day, so the need and demand of economical fuel also increases. About 9.3 billion gallons of biodiesel are consumed in at least 56 countries annually, and 58 percent of that is consumed by only five countries. so, to fulfill that requirement alternative sources of energy such as biodiesel are becoming more and more popular. Biofuel can be produced from algae, which is an economical and renewable source. It can be grown anywhere, so using algae as a source eliminate a lot of requirements such as large land. It is also environmentally friendly and not hazardous to the nature as in the case of obtaining fuel from the fossils. Algae are organisms that grow in aquatic environments and use light and carbon dioxide (CO2) to create biomass. There are two classifications of algae: macroalgae and microalgae. Macroalgae, which are measured in inches, are the large, multi-cellular algae often seen growing in ponds. These larger algae can grow in a variety of ways. The largest multicellular algae are called seaweed; an example is the giant kelp plant, which can be more than 100 feet long. Microalgae, on the other hand, are measured in micrometers and are tiny, unicellular algae that normally grow in suspension within a body of water. Algae are sunlight-driven cell factories that convert carbon dioxide to potential biofuels, foods, feeds and high-value bio actives. Biodiesel is produced currently from plant and animal oils, but not from microalgae. This is likely to change as several companies are attempting to commercialize microalgal biodiesel. The algae can be grown using open pond system or closed loop system, the open pond is cost less to build but the chances of contamination are high, therefore closed loop system is preferred. A bioreactor is design which acts as a closed loop system. The algal oil is extracted and then by transesterification biodiesel is obtained. The comparison between the use of conventional diesel and the various biodiesels showed that, if the engine is correctly tuned for biodiesel operation, it can produce the same level of performance (torque and power) as with diesel fuel, but producing less smoke. And it was also possible to show that for the same level of allowable smoke the power and the efficiency were higher with biodiesel, when compared to diesel. This means that if an engine is carefully tuned, it is possible to switch from diesel to biodiesel without having to sacrifice performance.

Project Objectives

• To contribute to energy security by providing domestically sourced fuels.
• To maintain and enhance the natural resource base and environmental quality.
• To produce fuel that is economically viable.
• To enhance the quality of life for society as a whole.

Project Implementation Method

Algal production:

microalgae is grown in the photobioreactor. nutrients such as phosphorus, nitrogen and silicate is provided along with co2, water and sunlight

algal harvesting:

microalgae can be harvested by some conventional processes, which include filtration, flocculation, centrifugation, foam fractionation, sedimentation, froth floatation, and ultrasonic separation.

Extraction of Oil from Algal Biomass:

microalgae produce a cell wall containing lipids and fatty acids, which differ them from higher animals and plants. There are different methods of oil extraction from algae, such as mechanical and solvent extraction.

Mechanical oil extraction:

The oil from nuts and seeds is extracted mechanically using presses or expellers, which can also be used for microalgae. The algal biomass should be dried prior to this process. The cells are just broken down with a press to leach out the oil. About 75% of oil can be recovered through this method and no special skill is required. The topare extracted oil through screw expeller by mechanical pressing (by piston) and osmotic shock method and recovered about 75% of oil from the algae.

Solvent based oil extraction:

Oil extraction using solvent usually recovers almost all the oil leaving only 0.5–0.7% residual oil in the biomass. Therefore, the solvent extraction method has been found to be suitable method rather than the mechanical extraction of oil and fats. The amount of lipid extracted from microalgal biomass and further yield of highest biodiesel depends mainly on the solvent used. Several organic solvents such as chloroform, hexane, cyclo-hexane, acetone, and benzene are used either solely or in mixed form. The solvent reacts on algal cells releasing oil, which is recovered from the aqueous medium. This occurs due to the nature of higher solubility of oil in organic solvents rather than water. Further, the oil can be separated from the solvent extract. The solvent can be recycled for next extraction. Out of different organic solvents, hexane is found to be most effective due to its low toxicity and cost.

Transesterification:

This is a process to convert algal oil to biodiesel, which involves multiple steps of reactions between triglycerides or fatty acids and alcohol. Different alcohols such as ethanol, butanol, methanol, propanol, and amyl alcohol can be used for this reaction. However, ethanol and methanol are used frequently for the commercial development due to its low cost and its physical and chemical advantages he reaction can be performed in the presence of an inorganic catalyst (acids and alkalies) or lipase enzyme.In this method, about 3 mol of alcohol are required for each mole of triglyceride to produce 3 mol of methyl esters (biodiesel) and 1 mol of glycerol (by-product). Glycerol is denser than biodiesel and can be periodically or continuously removed from the reactor in order to drive the equilibrium reaction.

Benefits of the Project

• biodiesel benifit:
•  Biodiesel is a domestically produced, clean-burning, renewable substitute for petroleum diesel. Using biodiesel as a vehicle fuel increases energy security, improves air quality and the environment, and provides safety benefits.
• Biodiesel is Cleaner Fewer pollutants, less soot, hydrocarbons, carbon monoxide, and sulfur dioxide are produced. It is non-toxic and biodegradable.
• Safer: Petroleum diesel has a flash point of 52°C, so storing and transporting it can be hazardous. However, biodiesel has a much higher flashpoint of 150°C.
• Produced locally: Biodiesel eliminates the issues that come with mining, drilling, transportation, and processing of coal and oil/natural gas. 
• benifits of using algae as a source:
• Algae grows at higher efficiency levels than other biofuel crops.
• Algae is more productive than other forms of biomass.
• Algae is a renewable resource.
• Algae is something that almost anyone can grow
• Algae biofuels work with our current distribution system
• Ability to grow throughout the year, therefore, algal oil productivity is higher in comparison to the conventional oil seed crops
• Higher tolerance to high carbon dioxide content
• The consumption rate of water is very less in algae cultivation
• No requirement of herbicides or pesticides in algal cultivation
• The growth potential of algal species is very high in comparison to others
• Different sources of wastewater containing nutrients like nitrogen and phosphorus can be utilized for algal cultivation apart from providing any additional nutrient;
• The ability to grow under harsh conditions like saline, brackish water, coastal seawater, which does not affect any conventional agriculture

Technical Details of Final Deliverable

Production of economical and environmental friendly biodiesel using renewable source. 

Final Deliverable of the Project

Hardware System

Core Industry

Energy

Other Industries

Petroleum , Transportation

Core Technology

Shared Economy

Other Technologies

Sustainable Development Goals

Affordable and Clean Energy, Climate Action

Required Resources

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