The aim of this section of the website is too work out what quantity of biofuels could be produced from waste. The Biofuels from Waste section of the site describes biofuels produced from waste vegetable oil, used tyres and fuel produced from anaerobic digestors.
This page details the potential in the UK for the production of biodiesel from used cooking oil and the potential for oil produced from the tyre pyrolysis process.
The quantity of biodiesel which could be produced from waste cooking oil can be quantitfied in a manner similar to that of biodiesel produced direct from agriculture, as detailed in the biodiesel production section. The only difference being that rather than calculating crop yields it is nessisary to quantify the amound of waste oil available within the UK. It is very difficult to calculate this value as very few people or buisnesses keep records of their waste oils. However the DETR (Department of Energy Transport and Regions) esimates there is around 100,000 tonnes of recoverable waste oil produced each year within the UK (ref2). The following calculations are based on this estimate.
Biodiesel Yield from Waste Oil
Refering to the what is biodiesel section we know that there is around a 97% conversion
from raw vegetable oil to biodiesel during the transesterification process, this value is unlikly to change much even
if the oil has already been used for cooking.
Therefore:
Biodiesel Yield = 0.97 * 100,000 = 97,000 Tonnes per year or 110,227,000 litres per year
Total Biodiesel Production
The total biodiesel production assuming use of all the available waste oil would be around 110,227,000 litres per
year.
In 2002 the UK released for consumption 19.764 billion litres of diesel. By volume, the biodiesel produced from the waste vegetable oil could displace just under 0.6% of this diesel.
If this displacement is worked out in terms of energy then the value would be around 0.5%.
This is equivelent to around 100 million litres of diesel.
Quantifying the amount of oil which could be produced from tyre pyrolysis can be done in a similar manner to quantifying the amount of biodiesel produced from waste vegetable oil. It is simply a case of equating the amount of waste product available to the production yields. In the case of tyre pyrolysis the number of used tyres produced each year is well documented. What is less certain however is the amount of suitable road transport oil that can be yielded from the pyrolysis process itself. In the following calculations it is assumed that for 10kg of used tyre approximatly 0.85Kg of suitable road transport oil is produced. This number is based on a table of product yields for tyre pyrolysis from (ref20). It is being assumed that this oil is suitable as a diesel substitute.
Waste Tyre Resource
According to the Tyre Working Group 40,000,000 tyres are removed from british vehicle every year (ref3).
Of this 22% is used as
fuel, generally for electricity generation. 10% is used for rubber recycling. 10% is used in civilengineering applications.
12% is exported or used for other miscellaneous purposes. This leaves 46%, or 18.4 million tyres, which are sent to landfill.
These landfill destined tyres can be considered the feedstock for oil produced from tyre pyrolysis.
Oil Yield from Tyres
The average tyres weighs around 11Kg therefore 18.4 million tyres equates to 202.4 million Kg.
From each Kg of used tyre around 0.085Kg of light oil is produced, Therefore:
Total Tyre Pyrolysis oil Production:
= 202.4 million * 0.085 = 17.2 million Kg or 18,142,000 million litres per year
Assuming that this oil is suitable as a diesel substitute then by volume this is enough to displace around than 0.09% of current UK diesel consumption. By energy this figure becones even lower as tyre pyrolysis oil has an energy content of about half that of diesel. The result is a displacement of around 0.045%, a saving of just under 9 million litres of diesel.
SummaryUsing all the waste vegetable oil available to produce biodiesel and all the tyres due to go to landfill to produce fuel oil would result in: