Conversion of organic residue from solid-state anaerobic digestion of livestock waste to produce the solid fuel through hydrothermal carbonization

• Published in: Environmental engineering research Vol. 23; no. 4; pp. 456 - 461
• Main Authors: Yang, Seung Kyu, Kim, Daegi, Han, Seong Kuk, Kim, Ho, Park, Seyong
• Format: Journal Article
• Language: Korean
• Published: 2018
• Subjects: Organic waste; Hydrothermal carbonization; Hydrochar production; Renewable solid fuel; Solid-state anaerobic digestion
• ISSN: 1226-1025; 2005-968X

The solid-state anaerobic digestion (SS-AD) has promoted the development and application for biogas production from biomass which operate a high solid content feedstock, as higher than 15% of total solids. However, the digested byproduct of SS-AD can be used as a fertilizer or as solid fuel, but it has serious problems: high moisture content and poor dewaterability. The organic residue from SS-AD has to be improved to address these problems and to make it a useful alternative energy source. Hydrothermal carbonization was investigated for conversion of the organic residue from the SS-AD of livestock waste to solid fuels. The effects of hydrothermal carbonization were evaluated by varying the reaction temperatures within the range of $180-240^{\circ}C$. Hydrothermal carbonization increased the calorific value through the reduction of the hydrogen and oxygen contents of the solid fuel, in addition to its drying performance. Therefore, after the hydrothermal carbonization, the H/C and O/C atomic ratios decreased through the chemical conversion. Thermogravimatric analysis provided the changed combustion characteristics due to the improvement of the fuel properties. As a result, the hydrothermal carbonization process can be said to be an advantageous technology in terms of improving the properties of organic waste as a solid-recovered fuel product.