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Report 3 (of 5): Dunuts for
Diesel - United Kingdom
Introduction
Fuel energy on a large, useable scale
is available only from fossil sources. These sources
are finite and when burned cause pollution that damages
the environment. The need to reduce global warming
and harness sustainable energy has led to a search
for alternative fuel sources. Hydrogen and bio-fuels
such as alcohols and biodiesel are being made from
sustainable agricultural crops, producing valuable
by-products in the process.
Biodiesel is a renewable fuel that
can be manufactured in the kitchen using vegetable
oil or waste fat from restaurants and canteens. Making
biodiesel from waste fat is an alternative means of
disposing of a waste product that would otherwise
be sent to landfill sites, which are growing at an
unsustainable rate. Biodiesel is safe, biodegradable,
and better for the environment than petroleum diesel.
One of the main sources of the air pollution that
causes global warming is exhaust smoke from diesel
engines. Biodiesel has lower carbon dioxide (CO2)
emissions, it is non-toxic and it reduces serious
air pollutants such as particulates, carbon monoxide
and hydrocarbons.
One UK supermarket chain, Asda, is
doing its bit for sustainable waste management by
taking the waste fat from its canteens, restaurants
and rotisseries and turning it into a cleaner biodiesel
fuel which will soon to be used in Asda's fleet of
trucks, transporting produce around the country.
Sustainable Waste Management
In the UK, Asda produces between 50
and 90 million litres of waste cooking oil every year,
while its lorries clock up around 100 million road
miles each year. Individually, these factors can cause
damage to the environment through landfill waste and
CO2 emissions, but together they provide an environmentally
friendly solution. Trials undertaken showed that emissions
from using biodiesel are 20- 40 per cent lower than
those from low sulphur diesel (LSD) and 10-29 per
cent lower than emissions from ultra low sulphur diesel
(ULSD). Two Asda lorries have already begun testing
the fuel on the road and it is hoped that many more
will follow.
Biodiesel
Biodiesel can be used in any diesel
engine with few or no modifications. Although biodiesel
does not contain petroleum, the two fuels can be blended
successfully. Blends of 20 per cent biodiesel with
80 per cent petroleum diesel (B20) can be used in
unmodified diesel engines, or biodiesel can be used
in its pure form (B100), although engine modifications
are required to avoid maintenance and performance
problems, and more frequent cleaning may be necessary.
Biodiesel is virtually identical to
traditional petro-diesel in terms of performance and
fuel consumption (mileage), and has many advantages:
- It has a much higher flashpoint
than petro-diesel, making it safer to store, handle
and use.
- It is less toxic if ingested or
spilt.
- It requires no specialised dispensing
or storage equipment.
- It is more lubricating than diesel
fuel, which can increase the life of an engine.
Biodiesel is much better for the environment,
too.
- Biodiesel is more biodegradable.
Neat biodiesel degrades as fast as sugar and an
80/20 per cent petro/bio blend degrades twice as
fast as pure petro- diesel.
- Substituting 1 tonne of biodiesel
for petro-diesel prevents 3 tonnes of carbon dioxide
from entering the atmosphere.
- Biodiesel use reduces gas emissions
by up to 55 per cent.
How is it Made?
Biodiesel is made through a chemical
process called transesterification. Fats and
oils are chemically reacted with an alcohol to produce
chemical compounds known as fatty acid methyl esters.
Biodiesel is the name given to these esters when they
are intended for use as fuel.
A vegetable oil molecule is
made up of three esters attached to a molecule of
glycerin. To make biodiesel, the esters in
vegetable oil are separated from the glycerin.
During the process, the glycerin component
of vegetable oil is replaced with an alcohol. Either
ethanol or methanol can be used. Ethanol can be made
from sugar cane, cassava, or grains such as corn (maize)
or sorghum, and methanol can be made from coal, natural
gas or wood. Although methanol produces a more stable
biodiesel reaction, it is more dangerous and can be
fatal if swallowed. Ethanol is considered to produce
a superior grade of fuel, though it is more expensive
to buy.
Biodiesel can be made at home or in
schools, provided that the right supervision is available.
Understanding the necessary safety precautions before
attempting to use the chemicals involved is very important.
Please note: Due to the potential
hazards associated with producing biodiesel, the following
information is not intended as a recipe, but simply
provides a basic overview of one way to produce biodiesel
on a small scale. For more detailed explanations,
including quantities, times and temperatures, please
consult the Further Reading section.
Safety precautions
The essence of transesterification
safety is proper handling and storage of components
and maintenance of equipment.
If you are intending to make biodiesel
you should first read more widely and study these
safety rules:
- Pay attention to detail and be
patient.
- Avoid working quickly; work at
a leisurely place and do not under any circumstances
handle chemicals under the influence of alcohol
or drugs.
- Always wear proper safety equipment.
- Store all components out of reach
of children and away from heat and open fire.
- Never smoke within the working
area.
- Clean up spilled chemicals and
fats promptly and completely.
- Use your equipment according to
the manufacturer's recommendations.
- Be sure to strictly follow the
instructions given by the chemical manufacturers.
Equipment and materials
The best approach to making biodiesel
is to start off small and learn about what is involved.
This helps in working out the correct amounts of chemicals
such as lye to use per litre of vegetable oil. The
following equipment is recommended to make a small
batch of biodiesel using a blender (which must not
be used for food preparation):
- a clean workspace such as a laboratory,
garage or workshop;
- scales sensitive to at least 1
gram;
- litmus paper or a pH meter (pH
measures the acidity of a substance);
- a blender with a glass container;
- safety equipment such as goggles,
gloves, protective clothing, eye wash and vinegar
(to neutralise spilt chemicals);
- lye, also known as sodium hydroxide
or caustic soda, used as a catalyst;
- methanol or ethanol stored in a
fuel container;
- used cooking oil; and
- other equipment such as beakers,
paper towels, glass container and a small pump or
ladle.
Procedure
- Determine the amount of catalyst
(lye) needed for the batch of oil.
- Measure the quantity of methanol,
lye and vegetable oil.
- Dissolve lye into methanol by mixing
for up to 5 minutes.
- Mix this with vegetable oil in
a blender for 15 minutes.
- Allow glycerin to settle at the
bottom of the blender.
- Separate the glycerin from the
biodiesel after 8 hours.
- Clean up by properly storing leftover
chemicals in clearly labelled bottles and cleaning
all equipment. Do not use blender for food!
Figure 1. Procedure for making biodiesel. Based
on diagram by Tickell
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The Future of Biodiesel
Biodiesel offers an unrivalled range
of environmental benefits compared with alternative
transport fuels. It is sustainable and renewable;
it is safely biodegradable; it is much better in terms
of greenhouse gas emissions than fossil fuels; it
offers scope for recycling waste oils; it recycles
carbon; and it produces far fewer local air pollutants
than petroleum diesel. This renewable source of energy
also contributes to local development as biodiesel
is produced domestically and not imported from other
countries. Development of biodiesel industries could
strengthen domestic, and particularly rural economies.
Biodiesel is becoming ever more popular
with governments looking to reduce harmful emissions
and help the environment. France is the world's biggest
producer of biodiesel and its use in all diesel engines
is required by law. In America, the US Postal Service
uses biodiesel in all its fleet of vehicles. The European
Commission's (EC) Green Paper has the objective of
substituting 20 per cent of fuel energy by alternative
fuels such as biodiesel by the year 2020.
Please Note: In the UK, it is illegal
to use untaxed biodiesel in your engine for road use
under Customs and Excise law. For those who wish to
use biodiesel, it is advised that you contact us for
a registered list of suppliers and garages in the
UK.
For more information on Asda's biodiesel
scheme, please contact:
Public Relations
ASDA
Asda House, Southbank
Great Wilson Street
Leeds LS11 5AD
United Kingdom
Tel: 0113 241 8857
Fax: 0113 241 8015 |
General information on biodiesel
Canadian Renewable Fuels
Association (CRFA)
31 Adelaide Street East
P.O. Box 398
Toronto
Ontario M5C 2J8
Canada
Tel: (416) 304-1324
Fax: (416) 304-1335
The CRFA is a non-profit organisation
mandated to promote renewable bio-fuels (ethanol,
biodiesel) for automotive transportation through
consumer awareness and government liaison
activities. |
Further Reading
From the Fryer to the Fuel Tank:
The Complete Guide to Using Vegetable Oil as an Alternative
Fuel
Joshua and Kaia Tickell
£19.95, Ecologic Books, 1999, ISBN: 0966461614
This book, packed with photographs, graphs and diagrams,
provides concise, easy to understand instructions
for running a diesel engine on vegetable oil. It can
be bought from any good bookshop
Websites
There are many websites dedicated
to making biodiesel, most from America. Here are just
some of them.
journeytoforever.org/biofuel.html
Provides information on everything from biodiesel
and organic gardening to solar cookers.
http://www.eugenebiosource.org/
Eugene BioSource is dedicated to the education, research,
and development of regionally-based energy derived
from contemporary biological sources.
http://www.veggievan.org/
Website of the authors of the book, From the Fryer
to the Fuel Tank, and includes the video that
accompanies the book.
www.afdc.doe.gov/altfuel/biodiesel.html
Glossary
Catalyst: A catalyst is a substance
that starts a reaction between other substances. In
making biodiesel, sodium hydroxide (lye) or potassium
hydroxide can be used. The amount of catalyst used
in the biodiesel reaction depends on the pH of the
vegetable oil. A successful biodiesel reaction depends
on the ability to measure the pH of the oil.
Free fatty acids: Fats and
oils are often called fatty acids because they are
acidic. Used vegetable oil is more acidic than new
oil because it has been heated. It is important to
remove free fatty acids to stop the oil from solidifying.
To eliminate them, a catalyst is used to neutralise
the free fatty acids. More catalyst needs to be used
the greater the acidity of the oil.
Glycerin: Glycerin is a neutral,
sweet-tasting, colourless, thick liquid that freezes
to a gummy paste and which has a high boiling point.
Glycerin can be dissolved in water or alcohol, but
not oils. Glycerin has more than 1,500 known end uses,
including many applications as an ingredient or processing
aid in cosmetics, toiletries, personal care, drugs,
and food products.
Titration: A titration is a
reaction between the catalyst and the vegetable oil
to neutralise the free fatty acids. When the pH value
of diluted vegetable oil rises significantly, free
fatty acids will be neutralised (a pH of around 8
or 9).
Vegetable oil: Vegetable oils
contain concentrated energy from the sun. There are
many different vegetable oils that can be used to
make biodiesel, including palm, coconut, rapeseed,
peanut, sunflower, soybean and corn (maize). The main
advantage of vegetable oil is that it takes as little
as a few months to grow from seed.
This document is an output from
a project funded by the UK Department for International
Development (DFID) and the European Commission (EC)
for the benefit of developing countries. The views
expressed are not necessarily those of DFID or the
EC.
Acknowledgements
ITDG would like to thank Rachel
Fellows at ASDA for providing information on the project.
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