Wu Songbin, Zhuang Xiaomin, Ma Mingjing, Niu Le, Wang Jiaoyue, Xi Fengming
Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China; Key Laboratory of Pollution Ecology and Environmental Engineering, Chinese Academy of Sciences, Shenyang 110016, China; Key Laboratory of Terrestrial Ecosystem Carbon Neutrality, Liaoning Province, Shenyang 110016, China.
Sci Total Environ. 2024 Dec 1;954:176460. doi: 10.1016/j.scitotenv.2024.176460. Epub 2024 Sep 26.
A considerable amount of biomass ashes, resulting from agricultural waste field burning, wildfire, and solid biofuel incineration, is typically discarded in field or stored in dumps, where the alkaline oxides (CaO, MgO) they contain undergo carbonation and weathering-erosion processes over extended periods, continuously absorbing CO from the atmosphere and soil. However, their CO absorption behavior under natural conditions remains insufficiently explored in China. Using life cycle assessment (LCA) and material flow analysis (MFA) methods, this study developed a CO absorption analysis model for biomass ashes under natural conditions. We estimated the CO absorption of 9 different types of biomass ash from 1950 to 2022 through Monte Carlo uncertainty simulation. The results show that biomass ashes in China absorbed approximately 24.17Mt/year (95 % CI, 11.10-43.56) of CO under nature conditions, with the annual average CO uptake showing a steady increase from 1950 to 2022. The total CO uptake reached 856.85Mt (95 % CI, 368.73-1526.01) over these decades, mainly due to the significant contribution of biomass ash produced by domestic straw burning and fuelwood combustion, which accounted for 51.97 % and 22.08 %, respectively. Our findings highlight the substantial carbon sink benefits of biomass ash, providing valuable insights for further studies on carbon cycles in natural ecosystems and the potential integration of biomass ash in Carbon Capture, Utilization, and Storage (CCUS) technologies.
大量生物质灰源自农业废弃物田间焚烧、野火以及固体生物燃料焚烧，通常被丢弃在田间或存储于垃圾场，其中所含的碱性氧化物（CaO、MgO）会在较长时期内经历碳酸化和风化侵蚀过程，持续从大气和土壤中吸收二氧化碳。然而，在中国，它们在自然条件下的二氧化碳吸收行为仍未得到充分研究。本研究采用生命周期评估（LCA）和物质流分析（MFA）方法，建立了自然条件下生物质灰的二氧化碳吸收分析模型。通过蒙特卡洛不确定性模拟，我们估算了1950年至2022年9种不同类型生物质灰的二氧化碳吸收量。结果表明，中国的生物质灰在自然条件下每年吸收约2417万吨（95%置信区间，1110 - 4356万吨）二氧化碳，1950年至2022年期间年均二氧化碳吸收量呈稳步上升趋势。这几十年间二氧化碳吸收总量达到85685万吨（95%置信区间，36873 - 152601万吨），主要得益于国内秸秆焚烧和薪材燃烧产生的生物质灰的显著贡献，分别占比51.97%和22.08%。我们的研究结果突出了生物质灰巨大的碳汇效益，为进一步研究自然生态系统中的碳循环以及生物质灰在碳捕获、利用与封存（CCUS）技术中的潜在整合提供了有价值的见解。
