Modifying pyrolysis behavior and products distribution of sewage sludge and water hyacinth by microwave pretreatment and subsequent calcium oxide catalytic co-pyrolysis

作者：Wei, Chen; Chen, Liyao; Yu, Zhaosheng^*; Liang, Jianyi; Ma, Xiaoqian

来源：Biomass Conversion and Biorefinery, 2023, 13(13): 11853-11864.

DOI：10.1007/s13399-022-02911-5

• Catalytic pyrolysis
• Sewage sludge
• Water hyacinth
• Calcium oxide
• Microwave pretreatment

With the continual increase of sewage sludge (SS) and water hyacinth (WH), it became an emergency to dispose these two wastes in an efficient and sustainable way. In this study, pyrolysis behavior and products distribution of SS and WH by microwave pretreatment and subsequent calcium oxide catalytic co-pyrolysis was analyzed by thermo-gravimetric analysis and pyrolysis gas chromatography/mass spectrometry. Promotion effect was found during the pyrolysis process when the proportion of WH exceeding 50%. WH5SS5 was the best mixing ratio due to its lowest average activation energy (199.70 kJ/mol) and highest total peak area (2.10x10(9)). The addition of CaO reduced the yields of acids and sugars by 10.52% and 5.08%. Meanwhile, aldehydes and ketones became the main products after adding CaO, with the proportion of 20.05% and 21.12%, respectively. Increasing microwave pretreatment power and time could reduce the activation energy with the minimum value of 199.70 kJ/mol (P567). The total peak area was also evaluated from 1.41x10(9) to 2.22x10(9) (T10). Comparing with increasing microwave pretreatment power, extending microwave pretreatment time was more effective. Besides, microwave pretreatment increased the yields of aldehydes while the yields of ketones reduced. Pentanal accounted for the largest proportion of pyrolysis products with the maximum yields of 25.62% at WH0SS10, which indicating that microwave pretreatment and subsequent calcium oxide catalytic co-pyrolysis of SS and WH has potential to produce pentanal.