During the design process two key areas have been considered; the Life Cycle Assessment (LCA) of 1 tonne of Biodiesel and the Waste Management Strategy for the production process.
Life Cycle Assessment (LCA)
The Life Cycle Assessment (LCA) completed was based on the ISO-standard 14040, which defines LCA and sets out the procedures for its implementation. The steps taken were; goal and scope definition, inventory analysis, impact assessment and interpretation.
The goal and scope definition set out the boundaries for the assessment, which started at the cultivation of the seed through the oil extraction process to the refining of Biodiesel from oilseed rape oil.
The inventory analysis considered all of the inputs and outputs from the processes within the defined limits.
The impact of each of these items was then given a ranking (from 1 to 5) depending on the expected significance of the impact.
The interpretation showed that there are clear environmental benefits to be gained from the use of Biodiesel. The impact assessment demonstrates that the negative impacts of production of the fuel are not expected to be severe. The average ranking given to items was 3; this means that the item has a small impact and is within existing regulations.
A carbon balance for Biodiesel was performed based on previously published studies. The key conclusion was that Biodiesel absorbs approximately as much carbon dioxide during cultivation as it releases when burnt; therefore Biodiesel is approximately carbon neutral.
Waste Management Strategy
Waste products were considered in terms of their quantity and the methods available for their disposal. The materials considered were:
- Waste plant material and stones from oil extraction - expected to go to landfill or returned to be spread over the agricultural farm land where appropriate.
- Press cake - high protein bi-product from oil extraction to be sold as animal feed within the agricultural industry.
- Glycerol - a bi-product of the refining of Biodiesel from oilseed rape oil, which can be sold to the pharmaceutical industry.
- Waste water - produced at two stages of the refining process and is to be treated and recycled at the refinery.
- Methanol - used in the initial reaction to produce Biodiesel, but is not consumed, therefore it can be recovered and recycled within the refining process.
