Upgrading exhausted olive cake to an alternative solid biofuel of higher added value
The present idea includes critical actions for the upgrade of the exhausted olive cake, already sold as a fuel, using appropriate natural processes for the separation of olive pulp-skin and olive stones.
A disadvantage of the exhausted olive cake is that it contains the fraction of olives from their pulp and skin, resulting in characteristic odor that make it often unpleasant to use. Moreover, it contains high ash rates (more than 5%), which cause particulate emissions during its burning. However, it is possible to upgrade the fuel obtained from the processing of the olives by separating the pulp and skin from the olive stone. This separation may be carried out by centrifuging the exhausted olive cake.
Olive stones have very low ash content (less than 1%) which is comparable to the best quality class of wood pellets circulating in the market (A1). Moreover, they have higher net calorific value and during their combustion less dust and fume is produced, in addition to the easiest flow inside the burners. Olive pits have no odor problems and can be stored for a longer time, thus it is a product of higher added value.
Stage of development
The technology has been validated in the lab (TRL4).
Challenge and needs
Next steps target the validation or even the demonstration of the technology to the relevant environment of a potential business/industrial partner (upscaling of the TRL to level 5 or 6). At the premises of a potential partner, the exhausted olive cake will be separated into pulp-skin and stones. Appropriate physicochemical analyses of the olive stones (humidity, ash, volatiles, elemental analysis, calorific, etc.) and a full qualitative characterization of these will be made. Pelletization and torrefaction testing will be used to upgrade the final product. As a centralized action, the overall cost / benefit inventory of fuel from biomass and stones will be conducted.
A prior art research is scheduled to be done
Potential markets and targets
By upgrading exhausted olive cake to a product of higher added value, the industrial sector can increase its profits through the production and sale of a new, upgraded solid biofuel, and reduce its impact by using a more environmental friendly, self-produced alternative fuel.
Operators of pomace oil mills.