TY - JOUR
T1 - Emerging potential of spent coffee ground valorization for fuel pellet production in a biorefinery
AU - Atabani, A. E.
AU - Mahmoud, Eyas
AU - Aslam, Muhammed
AU - Naqvi, Salman Raza
AU - Juchelková, Dagmar
AU - Bhatia, Shashi Kant
AU - Badruddin, Irfan Anjum
AU - Khan, T. M.Yunus
AU - Hoang, Anh Tuan
AU - Palacky, Petr
N1 - Funding Information:
The authors extend their appreciation to the Deanship of Scientific Research at King Khalid University for funding this work through the research groups program under the Grant Number R.G.P.2/105/43.
Publisher Copyright:
© 2022, The Author(s), under exclusive licence to Springer Nature B.V.
PY - 2022
Y1 - 2022
N2 - Abstract: The global market for fuel pellets (FPs) has been steadily growing because of a shift to coal substitutes. However, sustainability and the availability of biomass are the main issues. Various kinds of bio-wastes can be valorized through cutting-edge technologies. In the coffee industry, a valuable organic waste called spent coffee grounds (SCGs) is generated in bulk. SCG can be divided into two components, namely spent coffee ground oil and defatted spent coffee grounds (DSCG). SCG and DSCG can be used to produce FPs with excellent higher heating values. This review highlights that burning FPs composed of 100% SCG is not feasible due to the high emission of NOx. Moreover, the combustion is accompanied by a rapid temperature drop due to incomplete combustion which leads to lower boiler combustion efficiencies and increased carbon monoxide emissions. This was because of the low pellet strength and bulk density of the FP. Mixing SCG with other biomass offers improved boiler efficiency and emissions. Some of the reported optimized FPs include 75% SCG + 20% coffee silverskin, 30% SCG + 70% pine sawdust, 90% SCG + 10% crude glycerol, 32% SCG + 23% coal fines + 11% sawdust + 18% mielie husks + 10% waste paper + 6% paper pulp, and 50% SCG + 50% pine sawdust. This review noted the absence of combustion and emissions analyses of DSCG and the need for their future assessment. Valorization of DSCG offers a good pathway to improve the economics of an SCG-based biorefinery where the extracted SCGO can be valorized in other applications. The combustion and emissions of DSCG were not previously reported in detail. Therefore, future investigation of DSCG in boilers is essential to assess the potential of this industry and improve its economics. Graphical abstract: [Figure not available: see fulltext.]
AB - Abstract: The global market for fuel pellets (FPs) has been steadily growing because of a shift to coal substitutes. However, sustainability and the availability of biomass are the main issues. Various kinds of bio-wastes can be valorized through cutting-edge technologies. In the coffee industry, a valuable organic waste called spent coffee grounds (SCGs) is generated in bulk. SCG can be divided into two components, namely spent coffee ground oil and defatted spent coffee grounds (DSCG). SCG and DSCG can be used to produce FPs with excellent higher heating values. This review highlights that burning FPs composed of 100% SCG is not feasible due to the high emission of NOx. Moreover, the combustion is accompanied by a rapid temperature drop due to incomplete combustion which leads to lower boiler combustion efficiencies and increased carbon monoxide emissions. This was because of the low pellet strength and bulk density of the FP. Mixing SCG with other biomass offers improved boiler efficiency and emissions. Some of the reported optimized FPs include 75% SCG + 20% coffee silverskin, 30% SCG + 70% pine sawdust, 90% SCG + 10% crude glycerol, 32% SCG + 23% coal fines + 11% sawdust + 18% mielie husks + 10% waste paper + 6% paper pulp, and 50% SCG + 50% pine sawdust. This review noted the absence of combustion and emissions analyses of DSCG and the need for their future assessment. Valorization of DSCG offers a good pathway to improve the economics of an SCG-based biorefinery where the extracted SCGO can be valorized in other applications. The combustion and emissions of DSCG were not previously reported in detail. Therefore, future investigation of DSCG in boilers is essential to assess the potential of this industry and improve its economics. Graphical abstract: [Figure not available: see fulltext.]
KW - Biorefinery
KW - Calorific value
KW - Circular bioeconomy
KW - Defatted spent coffee grounds
KW - Fuel pellets
KW - Spent coffee grounds
KW - United Nations Sustainable Development Goals
KW - Valorization
UR - http://www.scopus.com/inward/record.url?scp=85129297737&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85129297737&partnerID=8YFLogxK
U2 - 10.1007/s10668-022-02361-z
DO - 10.1007/s10668-022-02361-z
M3 - Article
AN - SCOPUS:85129297737
SN - 1387-585X
JO - Environment, Development and Sustainability
JF - Environment, Development and Sustainability
ER -