Producing biochar from forest residues can help resolve environmental issues by reducing forest fires and mitigating climate change. However, transportation and storage of biomass to a centralized facility are often cost-prohibitive and a major hurdle for the economic feasibility of producing biobased products, including biochar. The purpose of this study was to evaluate the environmental impacts and economic feasibility of manufacturing biochar from forest residues with small-scale portable production systems. This study evaluated the environmental performance and economic feasibility of biochar produced through three portable systems (biochar solutions incorporated (BSI), Oregon Kiln (OK), and air curtain burner (ACB)) using forest residues in the United States (US). Cradle-to-grave life-cycle assessment (LCA) and techno-economic analysis (TEA) were used to quantify environmental impacts and minimal selling price (MSP) of biochar respectively considering different power sources, production sites, and feedstock qualities. The results illustrated that the global warming (GW) impact of biochar production through BSI, OK, and ACB was 0.25–1.0, 0.55, and 0.61-t CO2eq/t biochar applied to the field, respectively. Considering carbon-sequestration, 1-t of biochar produced with the portable system at a near-forest site and applied to the field reduced the GW impact by 0.89–2.6 t CO2eq. For biochar production, the environmental performance of the BSI system improved substantially (60–70%) when it was powered by a gasifier-based generator instead of a diesel generator. Similarly, near-forest(off-grid) biochar production operations performed better environmentally than the operations at in-town sites due to the reduction in the forest residues transportation emissions. Overall, the net GW impact of biochar produced from forest residues can reduce environmental impacts (i.e., 1–10 times lower CO2eq emissions) compared with slash-pile burning. The MSP per tonne of biochar produced through BSI, OK, and ACB was $3,000–$5,000, $1,600, and $580 respectively considering 100 working days per year. However, with improved BSI systems when allowed to operate throughout the year, the MSP can be reduced to below $1000/t of biochar. Furthermore, considering current government grants and subsidies (i.e.,$12,600/ha for making biochar production from forest residues), the MSP of biochar can be reduced substantially (30–387%) depending on the type of portable system used. The portable small-scale production systems could be environmentally beneficial and economically feasible options to make biochar from forest residues at competitive prices given current government incentives in the US where excess forest biomass and forest residues left in the forest increase the risk of forest fires.

中文翻译：

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使用便携式系统从森林残留物中生产生物炭的生命周期评估和技术经济分析

从森林残留物中生产生物炭可以通过减少森林火灾和缓解气候变化来帮助解决环境问题。然而，将生物质运输和储存到集中设施通常成本高昂，并且是生产生物基产品（包括生物炭）的经济可行性的主要障碍。本研究的目的是评估使用小型便携式生产系统从森林残留物中制造生物炭的环境影响和经济可行性。本研究评估了通过三个便携式系统（结合生物炭解决方案 (BSI)、俄勒冈窑 (OK) 和空气幕燃烧器 (ACB)）使用美国 (US) 的森林残留物生产的生物炭的环境性能和经济可行性。考虑到不同的能源、生产地点和原料质量，从摇篮到坟墓的生命周期评估 (LCA) 和技术经济分析 (TEA) 分别用于量化生物炭的环境影响和最低售价 (MSP)。结果表明，通过 BSI、OK 和 ACB 生产生物炭对全球变暖 (GW) 的影响分别为 0.25–1.0、0.55 和 0.61-t CO2eq/t biochar。考虑到碳封存，在近森林地点使用便携式系统生产的 1 吨生物炭应用于田间，可将 GW 影响减少 0.89-2.6 吨二氧化碳当量。对于生物炭生产，当 BSI 系统由基于气化器的发电机而不是柴油发电机供电时，其环境性能显着提高（60-70%）。相似地，由于森林残留物运输排放量的减少，近森林（离网）生物炭生产作业的环境表现优于城内作业。总体而言，与斜堆燃烧相比，由森林残留物生产的生物炭的净 GW 影响可以减少环境影响（即，二氧化碳当量排放量降低 1-10 倍）。考虑到每年 100 个工作日，通过 BSI、OK 和 ACB 生产的每吨生物炭的 MSP 分别为 3,000-5,000 美元、1,600 美元和 580 美元。然而，随着 BSI 系统的改进，当允许全年运行时，MSP 可以降低到 1000 美元/吨以下。此外，考虑到当前的政府补助和补贴（即，利用森林残留物生产生物炭需要 12,600 美元/公顷），根据使用的便携式系统的类型，生物炭的 MSP 可以显着降低（30-387%）。考虑到美国政府目前的激励措施，在美国，过量的森林生物量和森林残留物会增加森林火灾的风险，因此便携式小规模生产系统可能是对环境有益且经济上可行的选择，以具有竞争力的价格从森林残留物中制造生物炭。