Fuel properties of avocado stone

- The consumption of avocado (Persea americana L.) has increased worldwide in recent years.
- The avocado stone was obtained from avocado industry.
- Till now avocado stone as a thermal energy source was not studied.
- The HHV obtained for avocado stone was 19.145 MJ/kg.
- The avocado stone added in biofuel technologies offers new perspectives for its valorisation.

The consumption of avocado (Persea americana L.) has increased worldwide in recent years. Part of this food (skin and seed or stone) is lost during industrial processing. Avocado is the fourth largest selling tropical fruit in the world, with an estimated global production of 4,717,102 t in 2014 and an increase of 139% in the last 20 years. Residual biomass produced in the avocado sector results from the large amount of guacamole manufacturers that generate byproducts with potentially high energy content, suitable for thermal energy production. The main residue, avocado stone, could be an important biofuel, but its potential usefulness as biomass is unknown. Therefore, the main objective of this study is to describe avocado stone energetic properties and to evaluate these parameters before consumption. For this purpose, the parameters analysed in this wok were: Moisture (35.2%), HHV (19.145 MJ kg−1), LHV (17.889 MJ kg−1), elemental composition (e.g. 48.01% C, 5.755% H, 0.447% N), Ash content (2.86%), or oil content (1.715%). The results were compared to olive stone and almond shell, having intermediate values between both. Finally, a correlation between the ultimate analysis and higher heating values (HHV) of avocado stone has been evaluated, being the best correlation HHV = 0.4373 C − 1.6701 with a bias error of −0.94% which indicates that it can be successfully used as a faster tool to accurately estimate avocado stone HHV. As main conclusion, this work opens new perspectives for using of avocado stone as a fuel for domestic or industrial heating.