以负碳排放为目标的生物质灰矿化CO2路径研究

将生物质能源开发利用与碳捕获、利用与封存结合，可实现CO₂负排放，是能源领域降低CO₂排放的重要技术之一。生物质直接燃烧后产生的生物质灰理论上可吸收并永久封存CO₂,但其能否实现负碳排放还需进行深入研究。基于此，分别在自然状态（空气氛围）、中等CO₂初始分压（101.3 kPa）和高CO₂初始分压（300～1 400 kPa）条件下开展了生物质灰矿化CO₂试验，测试了生物质灰的CO₂矿化量，并评估了3种矿化路径的负碳排放量。结果表明，从空气中吸收CO₂时，生物质灰的CO₂矿化性能最差，40 d内的最高CO₂矿化量仅为60.66 g/kg。在中等CO₂分压101.3 kPa条件下，可最高实现121.68 g/kg的矿化量，而初始分压1 400 kPa下的CO₂矿化量可达216.85 g/kg。综合考虑矿化过程的能源消耗和生物质灰...

CO2 Mineralization Pathway Investigation Using Biomass Ash for Achieving Negative Carbon Emissions

Combining the development and utilization of bioenergy with carbon capture, utilization and storage (BECCUS) is one of the important methods to reduce CO2 emissions in the energy field as it can achieve the negative carbon emissions. Biomass ash (BA) generated from the direct combustion of biomass, can be used to absorb and sequestrate CO2 permanently. However, the issue adopting biomass ash to achieve the negative carbon emissions should be investigated carefully. CO2 mineralization performance of biomass ash from atmospheric CO2 and CO2-rich gas streams with a moderate (101.3kPa) and high CO2 partial pressure (300~1400kPa) was experimented in terms of CO2 sequestration capacity. Moreover, negative carbon emissions of these three mineralization pathways were evaluated as well. Results showed that among all the three pathways, the lowest CO2 sequestration capacity with 60.66g/kg after 40 days was acquired when CO2 came from atmosphere. Comparatively, when the initial CO2 partial pressure was elevated to about 101.3kPa (i.e., the moderate CO2 partial pressure case), the maximum CO2 sequestration capacity of 121.68g/kg can be achieved. When CO2 partial pressure was increased to about 1400kPa (i.e., the high CO2 partial pressure case), a CO2 sequestration capacity of 216.85g/kg was obtained. The actual negative carbon emissions of three mineralization pathways of biomass ash were assessed by comparing CO2 emissions reduction ascribed to CO2 sequestration of biomass ash and CO2 emissions related to energy consumption in the mineralization process and biomass ash transportation. When the transportation distance of biomass ash was less than 207km, adopting this mineralization pathway in which CO2 came from the CO2-rich gas streams with a moderate CO2 partial pressure (101.3kPa) might be reasonable for achieving a highest negative carbon emission. When the transportation distance was above 207km, the pathway in which CO2 came from the gases with a high CO2 partial pressure should be sensible.