COMBINATION OF HYDROTHERMAL CARBONIZATION AND WET OXIDATION

An integrated system of hydrothermal carbonization (HTC) and wet oxidation (WO) as post-treatment technology for the products of HTC was proposed. The objective was to preferentially oxidize the dissolved organic carbon in the process waters over the chars while simultaneously improving the overall heat efficiency of the HTC process. In laboratory experiments, paper and brewer's spent grains were investigated as model biomasses. Furthermore, a new technology concept for HTC and WO was suggested based on the deep shaft -VerTech technology. The efficiency of combing HTC and WO to improve the energy autarchy of the overall process was determined by means of chemical oxygen demand data for chars and dissolved organic matter (DOM). Results provide evidence that both DOM and char underwent oxidation with a decrease in char yields. A promising finding is that the dissolved organic carbon was oxidized to a higher degree than the chars and that sufficient heat could be released under certain WO conditions to thermally sustain the HTC process.