Hydrothermal carbonization (HTC) of marine plastic debris

Once removed from the sea, some plastics cannot be recycled or reused. This debris has high calorific value which makes it suitable to use as fuel. For this reason, a mixture of plastic materials was subjected to hydrothermal carbonization using seawater as solvent. We could thus examine the characteristics of the final products obtained and test the feasibility of converting marine plastic debris into fuel. Results showed that raising the temperature of the process reduced the inorganic anions content and increased hydrochar NCV. In addition, thermobalance was used to look for differences in the thermal decomposition of the different solid residues, being hydrochar at 300 °C the most affected material. The content of inorganic compounds in the HTC-liquor increases as the process temperature rose. Amides, alcohols and alkanes were the main organic compounds found in all cases. Gases emissions also increased with temperature.Support for this work was provided by the CTQ2016-76608-R project from the Ministry of Economy, Industry and Competitiveness (Spain). The author M.E. Iñiguez also thanks the Ministry of Economy, Industry and Competitiveness (Spain) for a Ph.D. grant (contract grant number BES-2014-069473)