In the present study, the effect of temperature and residence time during microwave hydrothermal pretreatment (MHT) on hydrochar properties and pyrolysis behaviors was investigated. Experimental results indicated that higher heating value (HHV) and fixed carbon content gradually increased with increased pretreatment severity. Obvious reduction of oxygen content was found under MHT at 230 °C-15 min and 210 °C-35 min. Although lower mass yield was observed under severe conditions, corresponding energy yield was relatively higher. Crystallinity indexes of hydrochar demonstrated an upward trend with increased residence time. Unlike hydroxyl group, dissociation of acetyls was more favorable under prolonged residence time rather than increased temperature. Peaks in thermogravimetric and derivative thermogravimetric curves shifted to higher temperature region under severe conditions, indicating better thermal stability. Py-GC/MS analysis suggested that acids content was decreased but sugars increased with increased MHT severity. Moreover, compared to temperature, residence time was mainly responsible for acetic acid formation.
Bibliographical noteFunding Information:
We gratefully acknowledge the financial support from the National Natural Science Foundation of China (Nos. 21766019 and 21466022 ), International Cooperation Project of MOST. P.R. China ( 2015DFA60170-4 ), The Key Research and Development Program of Jiangxi Province ( 20171BBF60023 ), Science and Technology Research Project of Jiangxi Province Education Department (No. GJJ150213 ), Innovation and Entrepreneurship Development Fund of “Thousand talents program” Talent (No. 1001-02102082 ), Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development (No. Y707sb1001 )”.
© 2017 Elsevier Ltd
- Hydrochar properties
- Hydrothermal pretreatment
- Microwave irradiation
- Pyrolysis behaviors