Car chow: Russian scientists may turn discarded food into fuel for automobiles
The methods put forward by the scientists are more energy-efficient when compared to other alternatives and enable the conversion of all raw materials into biofuel with a minimal amount of discharge possible. Additionally, the method of hydrothermal liquefaction can be conveniently used in directly transforming wet biomass into biofuel without the energy-consuming stage of drying the raw materials.
Studies carried out by the United Nations revealed that about one-third of all food products created for human consumption are thrown away. The volume of discarded products varies from 100 kg per person in Europe and North America to 10 kg per person in the poor regions of Africa and Asia. The total volume of discarded products comes to about 1.3 billion tonnes annually.
The remains can be recycled by transforming them into biofuel that result in a win-win situation for ecology and energy-use. The conversion method used at present — fermentation of hydrocarbons and interesterification of lipids — are suitable for transforming only a portion of food waste (mostly of lipids), while the remains still have to be discarded.
The researchers applied the method of hydrothermal liquefaction where the waste is heated until 370 degrees Centigrade under pressure of 25 MPa. As a result, the remains transform into a brown liquid, which is a complex mixture resembling petrol.
To study the prospects of turning discarded food into biofuel, the scientists examined the products yielded through the hydrothermal liquefaction of (parmesan), cheese, meat (ham), and apples. The molecular composition of the ensuing biofuel was analyzed with high-resolution mass-spectroscopy.
«We discovered that the products from the hydrothermal liquefaction of meat and cheese are comprised of water-soluble and water-insoluble fractions. Apples furnish an only water-soluble fraction. The molecular composition of the resulting biofuel is quite varied and is reminiscent of products from wood pyrolysis (tar) rather than petrol. It turned out that the products from converting meat and cheese were quite similar to each other, while those of apples were substantially different,» said Yury Kostyukevich, a Skoltech research assistant.
Knowledge of the molecular composition of the products obtained from the hydrothermal liquefaction will allow scientists to develop the most optimal methods for their subsequent processing to produce fuel suitable for automobiles.
The results of the study have been published in The European Journal of Mass Spectroscopy.