Carbon Capture and Storage and Carbon Capture and Utilization refer to carbon dioxide management technologies for its removal from flue-gases, followed by carbon recycling or storage, aiming at limiting global warming. For large-scale deployment, geological storage is the most promising alternative but imposes an economic penalty to the emitting process, while the utilization monetizes carbon dioxide contributing to compensate for the large capture costs. The exergy concept builds a suitable framework to measure useful power according to the Second Law of Thermodynamics, such that maximizing exergy efficiency necessarily promotes sustainability. This work applies a novel framework for exergy assessment of processes with chemical reactions, which is employed to evaluate the performance of two methanol production routes from carbon dioxide from power plant flue-gas: the direct hydrogenation and the indirect conversion through natural gas bi-reforming for synthesis gas production. Exergy efficiency of the direct route is about 66.3%, against 55.8% for the indirect one, indicating the lower sustainability of the latter. Carbon capture and storage had the worst Exergy efficiency, even lower than the emission scenario, accounting for 44.8% against 53.5%. Exergy metrics pinpoint low scalability as the main drawback of the utilization technologies, despite high exergy and capture efficiency.

碳捕集与封存和碳捕集与利用指的是从烟道气中去除二氧化碳，然后再进行碳的再循环或存储，以限制全球变暖的二氧化碳管理技术。对于大规模部署，地质存储是最有前途的替代方法，但对排放过程造成经济损失，而利用则使二氧化碳货币化，从而弥补了巨大的捕获成本。火用概念建立了一个根据热力学第二定律测量有用功率的合适框架，从而使火用效率最大化必然促进可持续性。这项工作采用了一种新颖的框架，可以对具有化学反应的过程进行火用力评估，该方法用于评估电厂烟气中二氧化碳的两种甲醇生产路线的性能：直接加氢和通过天然气双重整转化为合成气的间接转化。直接路线的火用效率约为66.3％，而间接路线的火用效率为55.8％，表明后者的可持续性较低。碳捕集与封存的能效效率最差，甚至低于排放情景，分别占44.8％和53.5％。尽管能效和捕获效率很高，但能值指标将低可扩展性确定为利用技术的主要缺点。间接项目的8％，表明后者的可持续性较低。碳捕集与封存的能效效率最差，甚至低于排放情景，分别占44.8％和53.5％。尽管能效和捕获效率很高，但能值指标将低可扩展性确定为利用技术的主要缺点。间接项目的8％，表明后者的可持续性较低。碳捕集与封存的能效效率最差，甚至低于排放情景，分别占44.8％和53.5％。尽管能效和捕获效率很高，但能值指标将低可扩展性确定为利用技术的主要缺点。