LIFE CYCLE ASSESSMENT OF PYROLYSIS-DERIVED BIOCHAR FROM ORGANIC WASTES AND ADVANCED FEEDSTOCKS

摘要

Recent interest in reducing stress on the food-energy-water (FEW) nexus requires the use of renewable, organic products that can subsequently address environmental sustainability concerns, such as mitigating greenhouse gas emissions. Pyrolysis-derived biochar from organic wastes (e.g., nutrient-rich agricultural wastes and leftovers, forest harvest residues, and cattle manure) and advanced feedstocks (e.g., algae) is capable of addressing ever-increasing global FEW concerns. Biochar water-nutrient holding capacity and carbon sequestration are key attributes for improving organic farming and irrigation management. The major challenge to commercialize biochar production from organic wastes is the conversion process. Pyrolysis process is a cost-effective and successful approach in comparison to other conversion technologies (e.g., gasification) due to low energy requirement and capital cost, as well as high process efficiency and biochar quality. To determine the environmental impacts of the biochar production process, an analysis of the material, energy, and emission flows of a small-scale pyrolysis process is conducted for a real case study, using life cycle assessment method with the assistance of available life cycle inventory databases within OpenLCA software. The results demonstrate that this study is able to enhance sustainability aspects across FEW systems by (a) employing a portable refinery to address upstream challenges (i.e., collection, transportation, and preprocessing) of waste-to-biochar life cycle, (b) recycling domestic forest and agricultural residues (e.g., pine wood), (c) producing organic biochar-derived soil conditioners that can improve organic cropping and FEW systems. Ultimately, we conclude by discussing techno-economic and socio-environmental implications of biochar production from organic wastes and advanced feedstocks.