The potential of coffee stems  gasification to provide bioenergy for coffee farms: a case study in the Colombian coffee sector

Abstract

The coffee industry constitutes an important part of the global economy. Developing countries produce over 90% of world coffee production, generating incomes for around 25 million smallholder farmers. The scale of this industry poses a challenge with the generation of residues along with the coffee cultivation and processing chain. Coffee stems, obtained after pruning of coffee trees, are one of those abundant and untapped resources in the coffee supply chain. Their high lignocellulosic content, the low calorific value ranging between 17.5 and 18 MJ kg −1 and the low ash content make them a suitable solid fuel for thermochemical conversion, such as gasification. This research evaluates the feasibility of using these residues in small-scale downdraft gasifiers coupled to internal combustion engines for power and low-grade heat generation, using process modelling and the Colombian coffee sector as a case study. The producer gas properties (5.6 MJ Nm −3) and the gasifier's performance characteristics suggest that this gas could be utilized for power generation. A cogeneration system efficiency of 45.6% could be attainable when the system's low-grade heat is recovered for external applications, like in the coffee drying stage. An analysis of the energy demand and coffee stems availability within the Colombian coffee sector shows that the biomass production level in medium-to large-scale coffee farms is well matched to their energy demands, offering particularly attractive opportunities to deploy this bioenergy system. This work assesses the feasibility of providing coffee stem-sourced low-carbon energy for global coffee production at relevant operating scales in rural areas. Keywords Gasification. Coffee residues. Process modelling. Power and heat generation. Coffee sector. Energy demand Abbreviations CHP Combined heat and power CGE Cold gas efficiency daf Dry ash-free composition d.b. Dry-basis composition ER Equivalence ratio HGE Hot gas efficiency ICE Internal combustion engine LI Low income LMI Low-middle income LHV Low heating value MC Moisture content UMI Upper-middle income * Samira Garcia-Freites

Does coffee taste better with latte art? A neuroscientific perspective

“…The coffee industry is an important part of the global economy, considering that coffee is the second most-traded commodity worldwide (Hsu and Hung, 2005;Ida and M€ unchow, 2016;Liu et al, 2019). Coffee production in developing countries accounts for over 90% of the world's total coffee production, bringing income to 25 m farmers (Garcia-Freites et al, 2019). According to the statistics of the International Coffee Organization, the total consumption of coffee has increased by 2.2% from 2016/2017 to 2019/ 2020 (International Coffee Organization, ICO, 2020), which indicates that the global demand for coffee continues to increase.…”

Analysis and availability of lignocellulosic wastes: Assessments for Indonesia and Peru

“…Indonesia is recognized as a major coffee producer worldwide, being Brazil the largest producer. In contrast, Brazil produces about 3.9 times more MT of coffee beans than Indonesia, and an estimated stem biomass potential (2.7 kg of coffee stems per 1 kg of dry parchment of coffee) in the same proportions (Garcia‐Freites et al., 2019). Given massive production of residues, Brazil operates on the most advanced biomass energy recovery programs (de Oliveira et al.).…”

Mapping the Sustainability of Bioenergy to Maximise Benefits, Mitigate Risks and Drive Progress Toward the Sustainable Development Goals

“…The BSIM was applied to assess a case study of a full bioenergy value chain e using coffee stem residues in Colombia to provide feedstock for electricity generation. This case study was selected to undertake a full sustainability appraisal to complement previous techno-economic and GHG lifecycle assessments [73] and bioenergy process modelling studies [74] for the same project. This case study providing an opportunity to map sustainability of a bioenergy project developed specifically to drive sustainable development.…”