Researchers at Harper Adams University College in Newpoprt, Shropshire, are investigating the viability of using oilseed rape straw (OSR) pellets as an alternative to traditional fuels, reducing the need for fossil fuels and adding value to existing food crops.
Using agricultural residues can avoid the food versus. fuel dilemma that currently calls into question the use of some 'food' crops as a source of biofuel.
Current research, which is funded by the Claas Stiftung Foundation and the Douglas Bomford Trust, includes investigating the pelletisation of the straw, the effect that storage has on their value and quality, and the combustion behaviour of OSR straw pellets.
“There are two main sources of biomass for energy generation: purpose-grown energy crops and residual materials from food crops," said postgraduate researcher Leticia Chico-Santamarta (pictured). “At the moment, there isn’t a significant market for OSR straw in the UK, and a lot of it is chopped into the soil through ploughing. Developing a market would add value to the gross margin of the crop at farm level.
“By making the straw into pellets and increasing the bulk density, the net energy content per unit volume is also increased. Storage, transport and handing of the material are easier and cheaper, with pellets having a 42 per cent weight advantage over straw. To investigate the quality during storage, we have been conducting different tests, such as durability and compression tests, to see what effect handling and storage has on the material.”
The final stage in the investigation is a combustion test at the Energy Technology Centre at Cranfield University. For each combustion test, the emissions, temperature and amount of ashes are recorded.
Converting the straw into pellets has other benefits. Because generally it doesn’t need to be dried, the energy required to do so is low compared with other materials— approximately five per cent of the energy available in the straw.
