Hydrochars were prepared by hydrothermal carbonization (HTC) of maize silage previously treated at 55°C in a two-stage solid-state reactor system. The HTC was carried out in a 1-L stirred pressure reactor with pH regulation by citric acid. The treated silage carbonized at relatively mild conditions (190°C, 2h), and the hydrochars showed mainly amorphous macro-size features with a carbon content of 59-79% (ash-free, dry) and a higher heating value of 25-36MJkg -1. Temperature was the main influencing factor. The surface area according to Brunauer-Emmett-Teller (BET) analysis was highest at 190°C (12.3m 2g -1). Based on these results, the hydrochars are potentially interesting for applications such as an alternative fuel or a soil conditioner.
- Hydrothermal carbonization