Multi-objective operation optimization of spent coffee ground torrefaction for carbon-neutral biochar production

Wei-Hsin Chen; Kuan-Ting Lee; Kuan-Yu Ho; Alvin B Culaba; Veeramuthu Ashokkumar; Ching Joon Juan

doi:10.1016/j.biortech.2023.128584

Multi-objective operation optimization of spent coffee ground torrefaction for carbon-neutral biochar production

Bioresour Technol. 2023 Feb:370:128584. doi: 10.1016/j.biortech.2023.128584. Epub 2023 Jan 5.

Authors

Wei-Hsin Chen¹, Kuan-Ting Lee², Kuan-Yu Ho², Alvin B Culaba³, Veeramuthu Ashokkumar⁴, Ching Joon Juan⁵

Affiliations

¹ Department of Aeronautics and Astronautics, National Cheng Kung University, Tainan 701, Taiwan; Research Center for Smart Sustainable Circular Economy, Tunghai University, Taichung 407, Taiwan; Department of Mechanical Engineering, National Chin-Yi University of Technology, Taichung 411, Taiwan. Electronic address: weihsinchen@gmail.com.
² Department of Aeronautics and Astronautics, National Cheng Kung University, Tainan 701, Taiwan.
³ Department of Mechanical Engineering, De La Salle University, 2401 Taft Avenue, 0922 Manila, Philippines; Center for Engineering Sustainable Development Research, De La Salle University, 2401 Taft Avenue, 0922 Manila, Philippines.
⁴ Biorefineries for Biofuels & Bioproducts Laboratory (BBBL), Center for Trandisciplinary Research, Department of Pharmacology, SDC, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai 600077, India.
⁵ Nanotechnology & Catalysis Research Centre (NanoCat), Institute of Postgraduate Studies, University Malaya, 50603 Kuala Lumpur, Malaysia.

PMID: 36610482
DOI: 10.1016/j.biortech.2023.128584

Abstract

Many energy-intensive processes are employed to enhance biomass fuel properties to overcome the difficulties in utilizing biomass as fuel. Therefore, energy conservation during these processes is crucial for realizing a circular bioeconomy. This study develops a newly devised method to evaluate SCG biochars' higher heating value (HHV) and predict moisture content from power consumption. It is found that the increasing rates of HHV immediately follow decreases in power consumption, which could be used to determine the pretreatment time for energy conservation. The non-dominated sorting genetic algorithm II (NSGA-II) maximizes SCG biochar's HHV while minimizing energy consumption. The results show that producing SCG biochar with 23.98 MJ∙kg^-1 HHV requires 20.042 MJ∙kg^-1, using a torrefaction temperature of 244 °C and torrefaction time of 27 min and 43 sec. Every kilogram of biochar with an energy yield of 85.93 % is estimated to cost NT$ 12.21.

Keywords: Multi-objective optimization; Non-dominated sorting genetic algorithm II (NSGA-II); Power consumption; Spent coffee grounds (SCGs); Torrefaction and biochar.

MeSH terms

Biomass
Carbon*
Charcoal
Coffee*
Temperature

Substances

biochar
Carbon
Coffee
Charcoal