Preparation and Characterisation of Optimised Hydrochar from Hydrothermal Carbonisation of Macadamia Shells

Fangyu Fan, Zhifeng Zheng, Yun Liu, Yuanbo Huang, Zhengjun Shi

Abstract


The yield of macadamia shells (MSs) is huge. The preparation of hydrochar of MSs for the purpose of energy has broad prospects. This study investigated the possible optimum conditions for the most appropriate yield and higher heating value (HHV) of hydrochar through hydrothermal carbonisation (HTC) of MSs. The yield and HHV via HTC were systematically analysed by response surface methodology (RSM) using a synthetic weighted scoring method. The operating parameters included reaction temperature, reaction time, and water-to-biomass ratio. According to the mathematical model of RSM, the maximum response value was obtained under the following optimum conditions: reaction temperature, 220 °C; reaction time, 60 min; and water-to-biomass ratio, 11. The results showed that the reaction temperature exerted more remarkable influence than time and water-to-biomass ratio. Under the optimal conditions, the hydrochar yield and HHV were 57.58% and 22.69 MJ/kg, respectively. The results of elemental, proximate, Brunauer–Emmett–Teller, scanning electron microscopy, and Fourier transform infrared spectroscopy analyses showed that the hydrochar fuel properties improved compared with those of raw MSs. Furthermore, the surface structure and functional groups changed.

Keywords


Macadamia shells; Hydrothermal carbonisation; Hydrochar; Response surface methodology; Characterisation

Full Text: PDF

Welcome to BioResources! This online, peer-reviewed journal is devoted to the science and engineering of biomaterials and chemicals from lignocellulosic sources for new end uses and new capabilities. The editors of BioResources would be very happy to assist you during the process of submitting or reviewing articles. Please note that logging in is required in order to submit or review articles. Martin A. Hubbe, (919) 513-3022, hubbe@ncsu.edu; Lucian A. Lucia, (919) 515-7707, lucian.lucia@gmail.com URLs: bioresourcesjournal.com; http://ncsu.edu/bioresources ISSN: 1930-2126