Multi-objective operation optimization of spent coffee ground torrefaction for carbon-neutral biochar production
Document Type
Article
Publication Date
2-1-2023
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 degrees 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
Torrefaction and biochar, Multi-objective optimization, Power consumption, Spent coffee grounds (SCGs), Non-dominated sorting genetic algorithm II (NSGA-II)
Divisions
nanocat
Funders
National Science and Technology Council, Taiwan, R.O.C. (Grant No: MOST 109-2221-E-006-040-MY3, MOST 110-2622-E- 006-001-CC1 & MOST 110-3116-F-006-003-)
Publication Title
Bioresource Technology
Volume
370
Publisher
Elsevier Science Ltd
Publisher Location
THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND