Emerging potential of spent coffee ground valorization for fuel pellet production in a biorefinery

A. E. Atabani, Eyas Mahmoud, Muhammed Aslam, Salman Raza Naqvi, Dagmar Juchelková, Shashi Kant Bhatia, Irfan Anjum Badruddin, T. M.Yunus Khan, Anh Tuan Hoang, Petr Palacky

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)

Abstract

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.]

Original languageEnglish
Pages (from-to)7585-7623
Number of pages39
JournalEnvironment, Development and Sustainability
Volume25
Issue number8
DOIs
Publication statusPublished - Aug 2023

Keywords

  • Biorefinery
  • Calorific value
  • Circular bioeconomy
  • Defatted spent coffee grounds
  • Fuel pellets
  • Spent coffee grounds
  • United Nations Sustainable Development Goals
  • Valorization

ASJC Scopus subject areas

  • Geography, Planning and Development
  • Economics and Econometrics
  • Management, Monitoring, Policy and Law

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