Post-extractivism and Bioeconomy: An Experimental Analysis of Combustion and Pyrolysis Processes as Alternatives to Add Value to Agro-Residues (Coffee Husks) Generated in Farmer Cooperatives of the Ecuadorian Amazon

In practice, a post-extractivist vision for farmer communities in the Amazon demands the study and demonstration, in the field, of alternative economic activities that are not based on resource extraction but on adding value to currently generated residual biomass. Following principles of bioeconomy, this study presents an experimental analysis of a retort burner and a pilot-scale auger-type pyrolysis reactor used to convert coffee husks generated in a post-harvesting facility of a farmer´s cooperative into thermal energy and biochar, respectively. The study shows that use of coffee husks, whether for combustion or pyrolysis processes, can supply the thermal energy required by the post-harvesting processes. The combustion or pyrolysis of coffee husks avoids its accumulation and decomposition while replacing the fossil fuels used in post-harvesting operations, reducing costs and making the farmers independent of fossil fuel subsidies. Unlike combustion, the CO concentration in the flue gas during the pyrolysis process was below the eco-design standard of 500 mg/Nm3. According to the European Biochar Certificate, carbonized coffee husks can be regarded as biochar for soil amendment and carbon sequestration. A study is required to assess the ability of cooperatives to generate and trade carbon credits linked with the application of biochar in their cropping systems.