introduction: biofuel is a fuel that uses biomass from living organisms which may be plant, animal...

INTRODUCTION:

• Biofuel is a fuel that uses biomass from living organisms which may be plant, animal microorganisms etc.

• It uses sunlight as a renewable source.

• In short, a hope to meet the global energy

demands.

Why biofuels?

BIOETHANOL:

• Ethanol derived from agricultural sources such as sugar cane, corn, potato etc., produced by sugar or cellulosic fermentation is called bioethanol.

• Distinct features: It is renewable Posses a large variety of substrate Biodegradable Less toxic

It has high octane number using lead as an octane enhancer.

Can be integrated into existing road transport fuels.

Blended with petrol in different proportions,

most common blend is 10% ethanol and 90% petrol Known as E10.

BIOMASS SOURCES:

• corn fiber corn starch

sugar cane

cotton woods switch grass stover wood chips paper

MECHANISM:

• Bioethanol is mainly produced in three ways.

Sugar ethanol

Starch sugar ethanol

Cellulose + hemicellulose ethanol

SUGAR CANE

• Fermentation conditions:

Temperature -- 32˚C and 35˚C

pH -- 5.2.

STEPS OF PRODUCTION:• Microbial (yeast) fermentation of sugars

• Distillation

• Dehydration

• Denaturing

Prior to fermentation, some crops require sccharification or hydrolysis into carbohydrates.

FERMENTATION:

• Glycolysis

h

• Alcoholic fermentation

REACTIONS:

• During fermentation glucose and other sugars are converted into ethanol and carbon dioxide.

C6H12O6 → 2 C2H5OH+ 2 CO2 + heat

• During combustion ethanol reacts with oxygen to produce carbon dioxide, water and heat:

C2H5OH + 3 O2 → 2 CO2 + 3 H2O + heat

DISTILLATION:

• Water is removed and purity of obtained ethanol is 95%. The mixture is called hydrous ethanol.

• Dehydration

.• Modern method involves use of sieve tubes.

• Purity achieved by this method is 94%.

STATISTICAL ANALYSIS:

• The top 5 bioethanol producers in 2005 were:

Brazil - 16500 billion liters The United States -16270 billion liters China - 2000 billion liters The European Union - 950 billion liters India - 300 billion liters In Pakistan, bioethanol production during 2004-

2005 were 122,104 metric tons

MERITS:• Uses energy from renewable energy sources; no net CO2 is added to the atmosphere, making ethanol an environmentally beneficial energy source. •Toxicity of exhaust emissions is lower than that of petroleum sources

• Energy crops grown for the production of ethanol absorbs huge amounts of green house gases (GHG) released by the burning of fossil fuels. • Ethanol contains 35% oxygen that helps complete combustion of fuel and thus reduces particulate emission that pose health hazard to living beings.

DEMERITS:•Deriving ethanol from crops (e.g. -- corn) consumes copious amounts of nitrogen fertilizer and extensive top-soil erosion associated with cultivation of this particular crop.•The energy content of the petrol is much higher than the one of bioethanol. Burning 1 liter of ethanol gives 34% less energy than burning the same amount of petrol.

•Growing food crops for ethanol will effect agriculture and let to food crisis.

BIODIESEL:

Discovered by Rudolf Diesel in peanut oil. Alternative

fuel for diesel engines.

• Made from vegetable oil or animal fat

• Biodegradable

• Essentially non toxic.

• Can be used as Pure Biodiesel (B100) or blended

with petroleum diesel (B20).

SOURCES:

• Plants:

Edible and non edible vegetable oils like Jatropha, Sunflower ,canola, almond, Cooking oil etc.

• Animals:

Tallow, Poultry fat etc. • Microorganisms:

Algae, Bacteria, Fungi etc.

METHODS OF PRODUCTION:

• Trans esterification• Most common production method

• Uses vegetable oils and animal fats as feed stocks

• The reaction of a fat or oil with an alcohol to form esters (biodiesel) and glycerol

• Thermal cracking

CHEMICAL DEFINITION:

Chemically biodiesel molecules are mono-alkyl esters produced usually from triglyceride esters.

Triacylglycerol + 3 ethanol

Diesel + glycerol

MECHANISM:Trans esterification

PROCESSING OF BIODIESEL:

STATISTICAL ANALYSIS:

• Top 5 biodiesel producers in 2010:

United states – 750 million tons Argentina – 690 million tons Germany – 660 million tons France -- 630 million tons Brazil -- 510 million tons• In Pakistan, production of biodiesel during 2007-

2008 was 8340860 TOE (tonne of oil equivalent)

• MERITS:• Biodiesel can reduce the dependency on foreign oil. It

can decrease the import bill, by partially replacing the diesel consumption with domestically produced renewable fuel.

• The plantation of feed stocks and the subsequent production would generate significant employment. According to estimates by the Pakistan State Oil (PSO), 5000 acres of feed stock plantations would create 550 new jobs.

• Biodiesel has lower sulfur content and 78% life cycle reduction in carbon dioxide. This renewable fuel is extremely beneficial for the environment.

• Biodiesel provides one of the best energy returns among renewable fuels. It returns about 90% more energy than the energy that is invested to produce it. Ethanol, in comparison, only provides 25% of net energy.

DEMERITS:

•The foremost negative impact of developing a biodiesel industry is its usage of edible oil as an industrial raw material. Using a food product as a fuel would only increase the chances of famine in developing world.•Increased price relative to diesel.•Beginning of industry growth has caused some commodity price increases, that are limiting.

BIOMETHANE:

• Biomethane is also called biogas. It is produced by the anaerobic digestion of organic material by anaerobes.

• After digestion, the solid by-product can be used as fuel or fertilizer.

• It can be produced by either degradable wastage or by the use of energy crops fed into the digesters to supplement gas yields.

ANAEROBIC DIGESTION:

• There are four steps of anaerobic digestion:

Hydrolysis

Acidogenesis

Acetogenesis

Methanogenesis

MERITS:

•Reduced carbon emissions: Just like natural gas, biomethane releases some carbon dioxide and other greenhouse gases into the atmosphere. But these would be released anyway, if the organic matter that is used for biomethane production would simply be left to decompose.• Sustainability: Organic matter that is needed to produce biomethane is indefinite. It is also available in sufficient amounts all over the world regardless of geographical position and weather conditions which play an important role in

utilization of other alternative sources of energy such as solar energy and wind power.

• Energy independence: Unlike most types of energy that depend from international supply in the form of raw material such as uranium for nuclear power plants or direct supply such as fossil fuels, biomethane eliminates vulnerability to disruptions in the international energy supply market.

DEMERITS:•Odor : Some people who live nearby biogas plants complain about them producing unpleasant odors.

•Risk of explosion: Methane is highly explosive. Its production and transportation therefore require a high level of precaution.

•Loss of organic fertilizers and compost: Biomethane production requires large quantities of organic waste and there are concerns that increased production of biogas could cause shortages of supply with organic fertilizers and compost.

•Limited generation of electricity: Even if all organic waste would be collected by biogas plants, the amount of produced electricity would not be able to meet the demand.

• Genetic engineered microbes may enhance process efficiency.

• Dependence on oil producing countries can be reduced.

• Alternative feedstock sources can eliminate the possibility of food crisis.

FUTURE ASPECTS:

• Triacylglycerol and alcohol converts to which of the following:

(a). Biodiesel (b). Bioethanol ( c). Biomethane

• In anaerobic digestion, which of the following category of bacteria is included:

(a). Methanogenic bacteria

(b). Acidogenic bacteria

( c). Both a & b

MCQS

• Which one of the following is the source of bioethanol:

(a). Jatropha (b). Sugar cane

( c). Animal wastes

• Trans esterification is:

(a). Ester formation (b). Acyl group transfer

( c). Transfer of acyl group from ester to alcohol• Which is important in recycling of elements:

(a). Biomethane (b). Biodiesel

( c).bioethanol

• Why we prefer 2nd generation bioethanol over 1st generation?

• What are the four steps of anaerobic digestion?

• How bioethanol is produced from vegetable oil?

• Compare demerits of biodesiel and bioethanol and also conclude which is most beneficial?

SHORT QUESTIONS:

ANS: (1). (a).

ANS: (2). ( c).

ANS: (3). (b).

ANS: (4). ( c).

ANS: (5). (a).

ANSWERS:

THANK YOU FOR YOUR ATTENTION.