Teixeira Paula, Fernandes Auguste, Ribeiro Filipa, Pinheiro Carla I C
CQE-Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa, Portugal.
Materials (Basel). 2021 Aug 5;14(16):4379. doi: 10.3390/ma14164379.
The use of wastes of marble powder (WMP) and dolomite as sorbents for CO capture is extremely promising to make the Ca-looping (CaL) process a more sustainable and eco-friendly technology. For the downstream utilization of CO, it is more realistic to produce a concentrated CO stream in the calcination step of the CaL process, so more severe conditions are required in the calciner, such as an atmosphere with high concentration of CO (>70%), which implies higher calcination temperatures (>900 °C). In this work, experimental CaL tests were carried out in a fixed bed reactor using natural CaO-based sorbent precursors, such as WMP, dolomite and their blend, under mild (800 °C, N) and realistic (930 °C, 80% CO) calcination conditions, and the sorbents CO carrying capacity along the cycles was compared. A blend of WMP with dolomite was tested as an approach to improve the CO carrying capacity of WMP. As regards the realistic calcination under high CO concentration at high temperature, there is a strong synergetic effect of inert MgO grains of calcined dolomite in the blended WMP + dolomite sorbent that leads to an improved stability along the cycles when compared with WMP used separately. Hence, it is a promising approach to tailor cheap waste-based blended sorbents with improved carrying capacity and stability along the cycles under realistic calcination conditions.
将大理石粉废料（WMP）和白云石用作二氧化碳捕集吸附剂，极有可能使钙循环（CaL）工艺成为一种更具可持续性和生态友好型的技术。对于二氧化碳的下游利用而言，在CaL工艺的煅烧步骤中产生浓缩的二氧化碳流更为现实，因此煅烧炉需要更严苛的条件，例如高浓度二氧化碳（>70%）的气氛，这意味着更高的煅烧温度（>900℃）。在这项工作中，使用天然氧化钙基吸附剂前驱体，如WMP、白云石及其混合物，在温和（800℃，氮气）和实际（930℃，80%二氧化碳）煅烧条件下，在固定床反应器中进行了CaL实验测试，并比较了各循环中吸附剂的二氧化碳承载能力。测试了WMP与白云石的混合物，作为提高WMP二氧化碳承载能力的一种方法。对于在高温高浓度二氧化碳下的实际煅烧，煅烧白云石中的惰性氧化镁颗粒在混合的WMP + 白云石吸附剂中具有很强的协同效应，与单独使用WMP相比，这使得沿循环的稳定性得到提高。因此，定制廉价的基于废料的混合吸附剂，使其在实际煅烧条件下具有更高的承载能力和沿循环的稳定性，是一种很有前景的方法。
