Design and operation of a small-scale carbonization kiln for cashew nutshell valorization in Burkina Faso

This paper describes the process of planning, design, building and first operation tests of a carbonization reactor for the valorization of cashew nutshells, obtained as byproduct from small-scale cashew cultivation and processing in Bobo-Dioulasso, Burkina Faso. The main technical requirements for the reactor were: low cost and ease of construction, robustness, autothermal operation, no need for pre or post-treatments for feedstock and products, and readily useable product fractions in a local scale. Design modifications are discussed and justified. Characterization of the raw material, data from the first successful operational tests, as well as product distribution and characterization, are presented. This carbonization prototype allows for the sustainable valorization of an otherwise problematic biomass residue, creating added-value products that would enhance the economic profitability of local processors. The use of the main charcoal product as a fuel substitute for household cooking is preliminarily assessed, and the recovery of potentially valuable cashew nutshell liquid (CNSL) is accomplished. (C) 2019 International Energy Initiative. Published by Elsevier Inc. All rights reserved.