August 25, 2020
For the transportation industry, liquid biofuel is considered as alternative fuel source for petrol and diesel. Main reasons for this are increasing amount of fossil fuel imports and environmental concern. However, We don’t foresee a complete substitution of petroleum derived fuels by biofuel because of production capacity and engine compatibly point of view. Marginal replacement or blending is the solution that can reduce the fossil fuel imports significantly (*e.g. one crore litre of E10 saves Rs.28 crore of forex). And abate the radical climate change caused by automotive pollutants (*e.g., one crore litre of E-10 saves around 20,000 ton of CO2 emissions.)
Liquid biofuel is produced from biomass resources and used in place of, or in addition to, diesel or petroleum fossil fuels for the transportation industry.
Mainly from two processes:
Transesterification is a process of converting vegetable and plant oils into biodiesel fuel. It is a chemical reaction where lipids (fats and oils) reacts with alcohol (typically methanol or ethanol) to produce biodiesel and glycerol (an impure product).
Fermentation is a metabolic process in which an organism converts a carbohydrate, such as starch or a sugar, into an alcohol or an acid. For example, yeast perform fermentation to obtain energy by converting sugar into alcohol.
What is Bioethanol?
Bioethanol is mostly used as blending agent with petroleum to cut down smog-causing emissions for cars and automobiles.
What is Biodiesel?
Biodiesel is used as an additive to reduce vehicle emissions or in its pure form, as a renewable alternative fuel for fossil diesel (also called, petrodiesel) engines of automobiles.
Energy density: It is the amount of energy stored in a fuel per unit volume, expressed in SI units as joule per litre (J/L) or equivalent units.
Bioethanol has much lower energy content than petrol (about two-third of the energy content of gasoline on a volume base).
Biodiesel has lower energy content (about 8% less) than diesel – (about two-third of the energy content of gasoline on a volume base).
Bioethanol and Biodiesel are mixed with gasoline and petrodiesel for usage. These are called blends.
Bioethanol (also known as ethyl or grain alcohol) is a clear, colourless liquid that can be produced by the fermentation of virtually any source of sugar or starch, the most common sources being sugar cane, corn, wheat and sugarbeets.
The combustion of bioethanol results in a clean emission: heat, steam ad carbon dioxide. This infinite cycle of creation and combustion of energy makes bioethanol a carbon neutral fuel source.
|E10||A fuel mixture of 10% ethanol (as additive) and 90% gasoline
E10, a “substantially similar” gasoline, reduces dependence on fossil fuels and improves air quality.
|E15||A fuel mixture of 10.5% – 15% ethanol (as additive) and gasoline
E15 reduces dependence on fossil fuels and improves quality.
|E85||E85 consists of 51%-83% ethanol by volume
Flex Fuel Vehicle (FFV) use E85 (a high level ethanol-gasoline blend, also called flex fuel)
2% methanol is added to make the bioethanol denatured.
E85: reduces dependence on fossil fuels in future years.
Bioethanol is considered to be renewable because of these reasons:
1). Quick growth of trees that act as sources of bioethanol
2) The source plants use photosynthesis process that captures sunlight and CO2
3) Vehicle’s CO2 emission is in fact should be reused by the trees
Production of Biofuel: Future trend changes from using food-biomass to non-food biomass.
Lastly, all the above processes are apparently considered to be carbon-neutral.
Bioethanol is an environment-friendly transportation fuel.
*Typical value. Values depend on types of bioethanol and used vehicles.
Bioethanol burns cleaner.
For bioethanol, results show:
17% reduction in Hydrocarbon (HC) emissions
73% reduction in Carbon Monoxide (CO) emissions
19-48% reduction in Carbon Dioxide (CO2) emissions
*Values depend on types of bioethanol to be used.
Ethanol poses no threat to surface water and ground water.
Bioethanol is biodegradable; any kind of spill does not impact the environment like the gasoline spill.
In India, the use of ethanol will reduce import of fossil fuel (crude oil)
Focus in India: Developing biofuels produced from non-food biomass.
The definition of biodegradable is simple: It means an item that can break down into natural materials in the environment without causing harm. Other items also may biodegrade relatively easily, such as paper. Some products will biodegrade eventually decomposed into CO2, water and other natural materials in the environment with causing any harm.
Question: How does bioethanol reach you?
Production, delivery and transportation – from harvest field to the fuel station.
For Bioethanol production, lignocellulose needs pretreatment which breaks complex lignocellulose into simple sugars.
In the US and in Canada, most trucks on the road today run on a blend of 20% biodiesel (B20) and 80% (fossil-based) diesel . Some cars run on 5% to 10% biodiesel blend as well.
A diesel engine is compression-ignited (CI) where chemical (in fuel) is converted to mechanical energy.
Biodiesel is the environment-friendly fuel for compression-ignited (CI) diesel engines.
How does a compression-ignited (CI) diesel engine work?
Diesel engines (of vehicle) can run on biodiesel blends of 5% to 20% with little or no modification. An interchangeable fuel with conventional fossil diesel.
Diesel engines can run on biodiesel blend B2 to B20 with little or no modification.
But engine modification is necessary for biodiesel B100. When B100 is used, biodiesel is no longer a drop-in fuel for these vehicles.
Question: How do you know which vehicle needs what type of biodiesel?
Recommended by the manufacturer for each vehicle.
Biodiesel is a Drop-in Fuel*
Mileage compared – distance travelled
Better smoke and better odour. Biodiesel reduces toxic emissions.
Reduction of harmful emission by different blends.
1). Plant-based feedstock
Photosynthesis converts CO2 to feedstock
2). Short gestation crops
The trees or plants that require minimal investment and much less time to grow and require minimal maintenance (for example, Jatropha)
3). Used Cooking Oil
Trees take in carbon dioxide from the atmosphere for photosynthesis so plants can grow into tress and grow in relatively short time (12-18 months). Fossil fuel took million years.
Biodiesel facility converts feedstock to biodiesel and CO2.
Vehicles burn biodiesel to release CO2 which is recycled.
In India, the 2018 biofuel policy includes used cooking oil as a feedstock for the purpose of producing biodiesel. More information on biodiesel can be found on Chapter 10.
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