A study on torrefaction of spent coffee ground to improve its fuel properties

Nepal, Rabin; Kim, Hyeok Jin; Poudel, Jeeban; Oh, Sea Cheon

doi:10.1016/j.fuel.2022.123643

Cited by 20 publications

(19 citation statements)

References 44 publications

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“…In general, a slight decrease in the weight was found around 150 • C and this could be due to the removal of moisture and the release of low molecular weight volatile components. This observance is consistent with the previous study regarding combustion profile of SCG and its prepared solid fuel published by Nepal et al [9]. In addition, a big weight loss was observed in the temperature range of 220-360 • C, which could be related to the decomposition of hemicellulose and cellulose [40].…”

Section: Tga Analysissupporting

confidence: 93%

“…The peaks at 2924 and 2984 cm −1 can be assigned to -CH bonds of methyl (-CH 3 ) group in the caffeine molecule. Similar, the intensity of these peaks of feedstock were stronger than those of hydrochar, implying that the decomposition of big molecules during HTC [9]. Two peaks at 1739 and 1644 cm −1 can be related to the C=O stretching vibration in carboxyl, and their intensities reduced after HTC treatment caused by the decarboxylation reaction.…”

Section: Ftir Analysismentioning

confidence: 77%

“…Alternatively, SCG is a carbonaceous material and can be used as the feedstock to produce useful bioproducts. In particular, converting SCG to solid fuel by improving its fuel properties has been investigated by torrefaction of dried SCG at 250-350 • C for 0-30 min by Nepal et al [9]. Barbanera and Muguerza [10] performed torrefaction of SCG for the production of solid biofuels at 210-260 • C for 90 min.…”

Section: Introductionmentioning

confidence: 99%

“…As earlier described, HTC could be an energy-saving technology for converting high water containing feedstocks such as SCG when compared with conventional approaches such as torrefaction and pyrolysis. Additionally, in consideration of the composition of SCG, it belongs to lignocellulosic biomass primarily containing cellulose, hemicellulose, lignin, fatty acids, and other polysaccharides, thereby ensuring SCGs excellent raw materials for producing fuels and chemicals [9]. Among them, the preparation of solid fuel could be a potential application of SCGs.…”

Section: Introductionmentioning

confidence: 99%

“…Aside from these applications, SCG could be an excellent source for producing solid fuel. In addition, although few studies have investigated the use of SCG for preparing solid fuel, most studies have used traditional torrefaction as the conversion approach, and there is a lack of investigations on the alternative method-HTC [9,10]. As a result, in this study, the non-catalytic HTC of SCG was carried out at temperatures of 150-210 • C, a residence time of 30-120 min, and feedstock to water weight ratio of 1:5-1:15.…”

Section: Introductionmentioning

confidence: 99%

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Hydrothermal Carbonization of Spent Coffee Grounds for Producing Solid Fuel

Gallant

Salaudeen

et al. 2022

Sustainability

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Spent coffee grounds (SCG) are industrial biowaste resulting from the coffee-brewing process, and they are often underutilized and end up in landfills, thereby leading to the emission of toxic gases and environmental damage. Hydrothermal carbonization (HTC) is an attractive approach to valorize wet biomass such as SCG to valuable bioproducts (i.e., hydrochar). Thus, in this work, the HTC of SCG was carried out in a 500 L stainless steel vessel at 150, 170, 190, 210, and 230 °C for 30 min, 60 min, 90 min, and 120 min and a feedstock to water weight ratio of 1:5, 1:10, and 1:15, and the use of the resulting hydrochar as a solid fuel was evaluated. The results showed that a high energy recovery (83.93%) and HHV (23.54 MJ/kg) of hydrochar was obtained at moderate conditions (150 °C, 30 min, and feedstock to water weight ratio of 1:5) when compared with conventional approaches such as torrefaction. Following this, the surface morphology, functionality, and combustion behavior of this hydrochar were characterized by SEM, FTIR, and TGA, respectively. In short, it can be concluded that HTC is an effective approach for producing solid fuel from SCG and the resulting hydrochar has the potential to be applied either in domestic heating or large-scale co-firing plants.

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Section: Tga Analysissupporting

confidence: 93%

Section: Ftir Analysismentioning

confidence: 77%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Hydrothermal Carbonization of Spent Coffee Grounds for Producing Solid Fuel

Gallant

Salaudeen

et al. 2022

Sustainability

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Torrefied spent coffee grounds as biofillers for poly(butylene adipate‐co‐terephthalate) biocomposites

Kim,

Kwon,

Park

2024

J of Applied Polymer Sci

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In this study, poly(butylene adipate‐co‐terephthalate) (PBAT) biocomposites were generated from spent coffee grounds (SCGs) or torrefied SCG (TSCGs) using a melt compounding process. TSCGs were obtained at torrefaction temperatures of 230, 245, 260, 275, or 290°C for a duration of 60 min. Torrefaction enhanced the hydrophobicity, grindability, and biomass stability of the resulting composites by eliminating hemicellulose. Various concentrations of SCGs (10 and 20 wt.%) and TSCGs (10, 20, and 30 wt.%) were compounded into PBAT. The thermal, mechanical, and degradation properties of PBAT biocomposites were investigated. As SCGs and TSCGs were introduced, the crystallization temperature drastically increased. Compared with PBAT biocomposites with SCGs, PBAT biocomposites with TSCGs exhibited higher thermal stability and hydrophobicity, and improved mechanical properties. Further, alkaline hydrolysis occurred at a faster rate for biocomposites with biofillers than for neat PBAT. Therefore, this study demonstrated the improved compatibility between SCGs and PBAT by torrefaction.

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The influence of torrefaction on the biochar characteristics produced from sesame stalks and bean husk

Khairy

Amer

Ibrahim

et al. 2023

Biomass Conv. Bioref.

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Torrefaction encourages homogeneity and enhances the energy-producing capabilities of biomass. In the current study, bean husk (BH) and sesame stalks (SS) were torrefied for 30 and 60 min at operating temperatures of 200, 225, 250 and 275, and 300 °C with nitrogen purging. Mass yield (MY), higher heating value (HHV), energy yields (EY), and torrefaction severity index (TSI) were examined. The variations of the biochar characteristics, pyrolysis kinetics by applying two models (Coats and Redfern (CR) and Direct Arrhenius (DA)), and crystallinity index (CRI) were depicted. Depending on pyrolysis kinetics, thermodynamic activation parameters were derived to elucidate biomass pyrolysis. The alterations in the torrefied materials’ composition were also analyzed using Fourier transform infrared spectroscopy (FTIR). The calculations revealed that the torrefied SS and BH decreased MY by 32.74, 29.02% and decreased EY 26, 20.97%, increased high heating values by 14.1, 13.52%, increased fixed carbon by 55.1, 39.91% respectively, and had a slight reduction in bulk density (approximately 2%). Generally, 275 °C and 30 min were the optimal conditions for a balanced torrefaction of SS and BH based on the HHV that reached to 20.5, 16.2 MJ/kg and EY that reached to 86.16 and 85.56% respectively. The FTIR, XRD, and the thermogravimetric results showed that the torrefaction treatment altered samples owing to carbohydrate breakdown, a rise in lignin, and a reduction in hemicellulose as the temperature of the torrefaction process increased. The CR methodology yielded greater frequency factor (A) and activation energy (Ea) values than the DA method. The broadest peak width, lowest average Ea, and lnA were seen in sesame stalks that had been torrefied at 300 °C and 30 min that reached to 107.85 (kJ/mol) and 13.57 (min−1). Results indicated an excellent linear relationship with the index of comprehensive pyrolysis (CPI), CRI, atomic H/C ratio, severity index, and EY.

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A study on torrefaction of spent coffee ground to improve its fuel properties

Cited by 20 publications

References 44 publications

Hydrothermal Carbonization of Spent Coffee Grounds for Producing Solid Fuel

Hydrothermal Carbonization of Spent Coffee Grounds for Producing Solid Fuel

Torrefied spent coffee grounds as biofillers for poly(butylene adipate‐co‐terephthalate) biocomposites

The influence of torrefaction on the biochar characteristics produced from sesame stalks and bean husk

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