Life cycle analysis of charcoal production in masonry kilns with and without carbonization process generated gas combustion

Abstract

New technologies and emissions controls have been developed for the production of charcoal, but are not widely used in the industry. The present study seeks to evaluate the potential environmental impact of these new technologies as compared to traditional ones. A Life Cycle Assessment (LCA) of Brazilian charcoal produced with different technologies without and with the combustion of the gases in burners or furnaces was carried out. The inclusion of furnaces for the combustion of gases reduces all categories of potential environmental impacts by approximately 90% in both a circular masonry kiln and a rectangular masonry kiln with gas combustion. In the process of producing charcoal (gate-to-gate system boundary), in terms of climate change, the rectangular masonry kiln with gas combustion was approximately 63% less impactful than the circular masonry kiln with gas combustion. In the gate-to-gate analysis, the rectangular masonry kiln with gas combustion presented the best performance when not considering NO2 and SO2. Considering these emissions, there were changes in the impact categories of particulate matter emission and terrestrial acidification, and the circular masonry kiln with gas combustion presented better performance (for cradle-to-gate system boundary). The process in a rectangular masonry kiln without gas combustion presented a greater contribution to the categories of terrestrial impact ecotoxicity (98%), due to the emission of acetic acid especially.