Co-pyrolysis of food waste with coconut fiber: thermogravimetric analyzes and hydrogen yield optimization

ABSTRACT

Co-pyrolysis of food waste with coconut fiber to produce hydrogen is considered an effective strategy for clean waste disposal and high value-added product synthesis. This study investigated the co-pyrolysis mechanism and hydrogen yields of food waste and coconut fiber at different blending ratios by thermogravimetric analysis and regression optimization. A heating rate of 10 ℃/min ranging from 30 ℃ to 900 ℃ coupled with the Svante August Arrhenius kinetic equations were utilized to derive the activation energies of the samples. Thermogravimetric analysis presented positive synergistic effects between coconut fiber and food waste to accelerate weight loss rate, and the main pyrolysis peak (200 ~ 450 ℃) moved to low temperature areas as the coconut fiber proportion increased. Additionally, kinetics showed that the lowest activation energy was 29.28 kJ at 1:3 blending ratio of coconut fiber to food waste. Based on this, response surface methodology (RSM) by Design-Expert.V8.0.6 ((Box-Behnken Design) (BBD)) was applied to optimize the microwave co-pyrolysis parameters (1600 W microwave power, 5 mm feedstock size, and 74% food waste proportion), thus the predicted maximum hydrogen yield was 46.20 vol.%. This study contributes to ameliorating the potential for solid waste microwave co-pyrolysis for value-added products production, therefore providing a reference for the further development of clean disposal technology and waste resource utilization.

GRAPHICAL ABSTRACT

KEYWORDS:

• Co-pyrolysis
• food waste
• coconut fiber
• microwave
• biomass
• hydrogen yield

Abbreviations

FW	=	Food waste
CF	=	Coconut fiber
TGA	=	Thermogravimetric analysis
DTG	=	Differential Thermogravimetry analysis
E/(kJ·mol−1)	=	Activation energy
k0	=	Pre-exponential factor
R2	=	Correlation coefficient

Acknowledgments

This research was conducted at the College of Engineering, Nanjing Agricultural University, Nanjing, Jiangsu, China. The authors gratefully acknowledge the support of the National Key R&D Program of China [grant number 2019YFC1906103].

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by The National Key R&D Program of China [grant number 2019YFC1906103].

Notes on contributors

Jufei Wang

Jufei Wang is a PhD student, mainly engaged in biomass conversion research.

Chao Li

Chao Li is a PhD student, mainly engaged in biomass conversion research.

Samuel Mbugua Nyambura

Samuel Mbugua Nyambura is a PhD student, mainly engaged in biomass conversion research.

Jialiang Xu

Jialiang Xu is a post-graduate student, mainly engaged in biomass conversion research.

Hua Li

Hua Li is a professor, doctoral supervisor, mainly engaged in precision planting and harvesting equipment and biomass conversion technology equipment research.

Chunlei Geng

Chunlei Geng is a PhD student, mainly engaged in biomass conversion research.

Xuhui Li

Xuhui Li is a university lecturer, mainly engaged in biomass conversion technology equipment research.

Xuebin Feng

Xuebin Feng is a associate professor, mainly engaged in precision planting and harvesting equipment and biomass conversion technology equipment research.

Xueru Zhu

Xueru Zhu is a post-graduate student, mainly engaged in intelligent research and biomass conversion research.