Synopsis

• Introduction• Biofuel Sources• Generations• Waste water treatment mthods• Cost of biofuel• Applications of biofuel• Future aspects• Conclusion• References

INTRODUCTION

• The term biofuel is referred to liquid, gas and solid fuels predominantly produced from biomass. Biofuels include bioethanol, biomethanol, vegetable oils, biodiesel, biogas, bio-synthetic gas (bio-syngas), bio-oil, bio-char, Fischer-Tropsch liquids, and biohydrogen.

• Biomass refers to a wide variety of organic and natural resources that include solid biomass, liquid fuels and different types of biogases. Biofuels can actually be extracted or derived from both living and nonliving (they were at one point) materials.

BIOFUEL SOURCES

• Biofuel is actually generated through 100% renewable resources.

• Examples of renewable resources include forests and crops. Today, renewable biofuels are produced from a variety of different types of biomass that include sugar crops, corn crops, vegetable oil, algae, wood and wood by products.

GENERATIONS

• First generation of biofuel:• Bioethanol and biobutanol• Bio-ethanol can be produced from different kinds of raw

materials. These raw materials are classified into three categories of agricultural raw materials : simple sugars, starch and lignocellulose.

• Bio-ethanol is derived from alcoholic fermentation of sucrose or simple sugars, which are produced from biomass by hydrolysis process.

Cont…

• Biodiesel production:• Biodiesel is a renewable replacement to petroleum-

based diesel. Biodiesel is an alternative liquid fuel that can be used in any diesel engine without modification.

• Biodiesel is produced by a mono-alcoholic trans-esterification process, in which triglycerides reacts with a mono-alcohol (most commonly methanol or ethanol) with the catalysis of alkali, acids, or enzymes.

Cont...There are three basic methods of biodiesel production from oils and fats:* Base catalyzed transesterification of the oil.* Direct acid catalyzed transesterification of the oil.• Conversion of the oil to its fatty acids and then to

biodiesel.

Most of the biodiesel production is done with the base catalyzed reaction for several reasons:* It is low temperature and pressure.* It yields high conversion (98%) with minimal side reactions and reaction time.* It is a direct conversion to biodiesel with no intermediate compounds.

Biodiesel production process

Cont…

• The base catalyzed production of biodiesel generally occurs using the following steps:

• Mixing of alcohol and catalyst • Reaction• Separation • Alcohol Removal• Glycerin Neutralization• Methyl ester Wash• Product Quality and Registration

Second Generation• Jatropha

J. curcas containing highly unsaturated and fattyacids. It is probably the most highly promoted oilseed crop.The seeds contain alkaloids as well as curcin, a toxalbumin then the oil contain a fatty acid ‘‘curcanoleic acid’’.

• Castor beanCastor oil contains about 90% of the triglyceride as ricinoleic acid, a C18 monounsaturated and monohydroxylated fatty acid, without acute toxicity, i.e. a C12 hydroxylated derivative of oleic acid.  

Third Generation

• The extensive collections of microalgae have been created by researchers in different countries.

• Examples – Freshwater Microalgae Collection (University of Coimbra (Portugal).

• Then the collected strains were used in pharmaceutical purposes, food crops for human consumption and as energy source.

• Microalgae can fix CO2 from three different sources, namely:

CO2 from the atmosphere,CO2 in discharge gases from heavy industry, CO2 from soluble carbonates.

Cont..

• The lipid content of Nannochloropsis strains ranging from 39.4% to 44.9% of dry weight biomass.

• Transesterification of the lipids yielded 25 - 51% of fatty acid methyl ester (FAME) i.e. In biodiesel, total FAME content ranged between 11 and 21% of dry weight biomass.

• There are four major types of cultivation conditions for microalgae:

Photoautotrophic,Heterotrophic, Mixotrophic,Photoheterotrophic cultivation.

Phototrophic cultivation

• In Phototrophic method the microalgae use sunlight, as the energy source, and inorganic carbon (e.g., carbon dioxide) as the carbon source to form chemical energy through photosynthesis.

• In phototrophic cultivation of lipid content of microalgae, ranging from 5 % to 68%, depending on the type of microalgae species.

• The highest lipid productivity is about 179 mg/ L / d by Chlorella sp. under phototrophic cultivation.

Open pond production system

• This system can be categorised into natural waters (lakes, lagoons, and ponds) and artificial ponds or container.

• Raceway ponds are the most commonly used artificial system.

• In 2008, the unit cost of producing Dunaliella salina, one of the commonly cultivated algae strains, in an open pond system was about 2.55 per kilogram of dry biomass, was considered to be too high production for biofuels.

• There are several factors are determined, including, evaporation losses, temperature fluctuation in the growth media, CO2 deficiencies, inefficient mixing, and light limitation.

Race way ponds

Closed photo bioreactor

• Microalgae production based on closed photobioreactor technology .

• Closed systems include the tubular, flat plate, and column photobioreactors. The costs of closed systems are higher than open pond systems.

• It consist of an array of straight glass or plastic tubes .

Basic design of a horizontal tubular photobioreactor

Hetrotrophic cultivation

• The microalgae use organic carbon as the source of energy and carbon source is called heterotrophic cultivation.

• Some microalgae species (Chlorella protothecoides) show higher lipid content (40%)during heterotrophic growth.

Mixotrophic cultivation

• The microalgae use both organic and inorganic carbon (CO2) as a carbon source for growth.

• The microalgae are able to live under phototrophic or heterotrophic conditions, or both.

• Photoheterotrophic cultivation:• the microalgae require light using organic compounds

as the carbon source. • In photoheterotrophic cultivation needs both sugars and

light.

Algal biomass conversion processes

Thermochemical conversion

• It covers the thermal decomposition of organic components in biomass to yield fuel products, and is achieved by different processes such as;

Direct combustion, Gasification, Thermochemical liquefaction, Pyrolysis.

Biochemical conversion

• The biological process of energy conversion of biomass into other fuels includes anaerobic digestion, alcoholic fermentation and photobiological hydrogen production.

FOURTH GENERATION

• Biological hydrogen generation system is achieved by co-cultivating a unicellular green alga whose photosynthesis is driven by the visible light.

• The purple photosynthetic bacterium adsorbed infrared light . The system works only at low light intensities.

waste water treatment methods• wastewater treatment methods are broadly classified

into three categories; • physical• chemical • biological treatment• These methods are used to remove contaminants from

wastewater. • wastewater treatment procedures are classified as

primary, secondary, and tertiary wastewater treatment.

wastewater treatment processes

Cost of biofuel (ethanol)• In 200 5 and May 200 7 prices for ethanol feedstock is

between 6% and 68%. 

Current and projected future ethanol production costs, compared with recent (pre-tax) gasoline prices / litre of gasoline equivalent.

Cost of biodiesel

• The production costs falling by up to 37% between 2005 and

2030 in the United States.

Current and projected future biodiesel production costs, compared with recent(pre-tax) gasoline prices.

Applications of biofuel

1. Cells which use a primary fuel (usually an organicwaste such as corn husks) and generate a material such as hydrogen, which is then used as a secondary fuel within a conventional hydrogen/oxygen fuel cell.

2. Cells which generate electricity directly from an organic fuel such as glucose, using either enzymes or complete microorganisms.

3. Cells which combine the utilisation of photochemically active systems and biological moieties to harvest the energy from sunlight and convert this into electrical energy.

Future Aspects

• Currently total fossil fuel consumption levels of approximately 757 billion liters (200 billion gallons) per year, this requires the United States to develop a commercial infrastructure capable of producing approximately 227 billion liters (60 billion gallons) of biofuel per year.

• The production level of 24.6 billion liters (6.49billion gallons) in 2007, it is estimated that the maximum production levels of corn ethanol in the United States will reach approximately 57 billion liters (15 billion gallons) per year by 2015.

Conclusion

• The role of sustainable, cost-effective, and scalable feedstock production is one of the most pressing needs in the realization of a biofuels industry capable of replacing a significant portion of the fossil-fuel consumption of the United States. It is important to recognize that different feedstocks will need to be grown in different regions to meet the tonnage required.

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