Effects of dry and wet torrefaction pretreatment on microalgae pyrolysis analyzed by TG-FTIR and double-shot Py-GC/MS

• Main Authors: Gan, Yong Yang, Chen, Wei-Hsin, Ong, Hwai Chyuan, Sheen, Herng-Kuang, Chang, Jo-Shu, Hsieh, Tzu-Hsien, Ling, Tau Chuan
• Format: Article
• Published: PERGAMON-ELSEVIER SCIENCE LTD 2020
• Subjects: QR Microbiology
• Online Access: http://eprints.um.edu.my/36284/
• Institution: Universiti Malaya

TG-FTIR and double-shot Py-GC/MS were executed to investigate the effects of torrefaction pretreatment on microalga (Chlorella vulgaris ESP-31) pyrolysis. TG-FTIR was performed to analyze the pyrolysis and combustion gas of raw and wet torrefied microalgae, whereas double-shot Py-GC/MS was applied to investigate the product distributions of single and two-stage thermal degradation of the microalgae. From the result, wet torrefaction successfully eliminated the release of CO in the pyrolysis gas. The highest generation of C-H during pyrolysis was achieved by the microalgae pretreated with dilute sulfuric acid. In the combustion gas, the intensity of O-H absorption band was removed in the first stage after wet torrefaction. The Py-GC/MS analysis revealed that the fatty acids (48.22%) were the dominant component in the bio-oil derived from the microalgae pretreated by the dilute sulfuric acid in wet torrefaction. Meanwhile, the productivity of carbohydrate-derived products (anhydrous sugars) decreased from 18.58 to 0.39% in the pyrolytic bio-oil after the wet torrefaction pretreatment. In contrast, carbohydrate- and lipid-derived products were decreased in the bio-oil after the dry torrefaction pretreatment. Similarly, microwave-assisted wet torrefaction in sulfuric acid is an effective pretreatment technique to produce high-quality pyrolytic bio-oil for biofuel production. (C) 2020 Elsevier Ltd. All rights reserved.