Experimental study on the energy conversion of food waste via supercritical water gasification: Improvement of hydrogen production

• Published in: International journal of hydrogen energy 2019-02, Vol.44 (10), p.4664-4673
• Main Authors: Yan, Mi, Su, Hongcai, Hantoko, Dwi, Kanchanatip, Ekkachai, Shahul Hamid, Fauziah Binti, Zhang, Sicheng, Wang, Guobin, Xu, Zhang
• Format: Article
• Language: English
• Subjects: Catalyst; Food waste; Gasification; Hydrogen; Supercritical water
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2018.12.193

In this study, the model food waste was gasified to hydrogen-rich syngas in a batch reactor under supercritical water condition. The model food consisted of rice, chicken, cabbage, and cooking oil. The effects of the main operating parameters including temperature (420–500 °C), residence time (20–60 min) and feedstock concentration (2–10 wt%) were investigated. Under the optimal condition at 500 °C, 2 wt% feedstock and 60 min residence time, the highest H2 yield of 13.34 mol/kg and total gas yield of 28.27 mol/kg were obtained from non-catalytic experiments. In addition, four commercial catalysts namely FeCl3, K2CO3, activated carbon, and KOH were employed to investigate the catalytic effect of additives at the optimal condition. The results showed that the highest hydrogen yield of 20.37 mol/kg with H2 selectivity of 113.19%, and the total gas yield of 38.36 mol/kg were achieved with 5 wt% KOH addition Moreover, the low heating value of gas products from catalytic experiments with KOH increased by 32.21% compared to the non-catalytic experiment. The catalytic performance of the catalysts can be ranked in descending order as KOH > activated carbon > FeCl3 > K2CO3. The supercritical water gasification (SCWG) with KOH addition can be a potential applied technology for food waste treatment with production of hydrogen-rich gases. •Energy conversion of food waste in supercritical water was investigated.•Four different catalysts were employed to catalyze the SCWG of food waste for Improving of hydrogen production.•The maximum H2 yield (20.37 mol/kg) was achieved at 500 °C, 60 min, 2 wt% feedstock with addition of KOH.•Performance of the catalysts was ranked in the order KOH > activated carbon > FeCl3 > K2CO3.