Experimental Study on Pyrolysis of Rice Straw Catalyzed by CaO/Al2O3-Phosphate Mixture

• Published in: Bioenergy research 2022-12, Vol.15 (4), p.2006-2025
• Main Authors: Xu, Lianlian, Xu, Zhongwen, Zhang, Feng, Yuan, Yinmei, Cheng, Bin, Zhang, Chuang, Chen, Ping, Huang, Xiangyong, Lin, Yuyu, Gu, Mingyan
• Format: Article
• Language: English
• Subjects: Acetic acid; Acids; Agricultural wastes; Aldehydes; Aluminum oxide; Benzene; Biomedical and Life Sciences; Camphor; Catalysis; Catalysts; Corn straw; Dehydration; Fermentation; Furans; Furfural; Gas chromatography; Hydrocarbons; Jet engine fuels; Ketones; Levoglucosan; Life Sciences; Pesticides; Phenols; Phosphates; Plant Breeding/Biotechnology; Plant Ecology; Plant Genetics and Genomics; Plant Sciences; Potassium; Potassium phosphate; Potassium phosphates; Precursors; Pyrolysis; Pyrolysis products; Rice; Rice straw; Straw; Synergistic effect; Transitional aluminas; Wood Science & Technology
• ISSN: 1939-1234; 1939-1242
• DOI: 10.1007/s12155-022-10393-6

CaO and phosphates showed synergistic effects in the regulation of pyrolysis products in the pyrolysis of when they were directly mixed with camphor wood. The alkyl phenol yield increased during the pyrolysis process of corn straw fermentation residue directly mixed with KH 2 PO 4 supported by γ -Al 2 O 3 . Rice stalks from agricultural crops are often disposed as waste. However, the potassium phosphate impregnated raw straw pyrolysis with CaO and Al 2 O 3 has not been reported. This paper studied the synergistic effects of CaO or Al 2 O 3 and three potassium phosphates (i.e., KH 2 PO 4 , K 2 HPO 4 ·3H 2 O, and K 3 PO 4 ·3H 2 O) in the rice straw pyrolysis through pyrolysis–gas chromatography-mass spectrometer (Py-GC/MS) experiments. The results showed that CaO/Al 2 O 3 and potassium phosphates showed synergistic effects in the regulation of the types or contents of phenols, ketones, aldehydes, etc. and increased the contents of phenols, aldehydes, acids, and levoglucosan (LG) from most samples and increased those of ketones compared with those catalyzed by potassium phosphates alone. They were suitable for the production of ketone-rich and acid-low bio-oil, which is an important precursor for the preparation of power or jet fuel. The highest contents of ketones (HCK) reached 56.65% and 56.02% in the pyrolysis of K 3 PO 4 ·3H 2 O impregnated rice straw with CaO or Al 2 O 3 , respectively. The lowest contents of acids and acetic acid (LCA) were nearly or equal to 0, respectively. HCK and LCA were respectively significantly higher and lower than the values reported in the literatures for biomass catalytic pyrolysis using CaO/Al 2 O 3 and potassium phosphates alone or in combination. Dehydration reactions, etc. were further promoted under the co-catalysis of the two catalysts, and some phenols could be converted to benzene products, etc. For 50% K 3 PO 4 ·3H 2 O impregnated sample, the yields of furans reduced sharply after CaO addition. For most impregnated samples except 50% K 2 HPO 4 ·3H 2 O and 30% and 50% K 3 PO 4 ·3H 2 O samples, the contents of total furans and furfural increased after Al 2 O 3 addition. Highlights CaO/Al 2 O 3 and potassium phosphates showed synergistic effects in the regulation of the types or contents of phenols, ketones, aldehydes, etc. They were suitable for the production of ketone-rich and acid-low bio-oil, which was an important precursor for the preparation of power or jet fuel. Dehydration reactions, etc. were further promote