How the presence of O2 and NOx influences the alternate cycles of CO2 adsorption and hydrogenation to CH4 on Ru-Na-Ca/Al2O3 dual function material
How the presence of O2 and NOx influences the alternate cycles of CO2 adsorption and hydrogenation to CH4 on Ru-Na-Ca/Al2O3 dual function material
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DOI：
10.1016/j.jcou.2022.102343
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发表时间：
2022-11-29
影响因子：
7.7
通讯作者：
Gonzalez-Velasco, Juan R.
中科院分区：
文献类型：
--
作者：
Bermejo-Lopez, Alejandro;Pereda-Ayo, Benat;Gonzalez-Velasco, Juan R.
综合碳捕集利用-甲烷化（ICCU-Methanation）需要一种双功能材料（DFM），它首先捕获二氧化碳，然后将其转化为CH4，在交替的吸附和氢化周期中工作。ICCU技术可直接应用于离开燃烧室的烟气，其中通常含有氧化物质，如氧和氮氧化物。本文研究了组成为4%Ru-8%Na2CO3-8%CaO/Al2O3的DFM在O2（0-10%）和NOx （0-2000 ppm）交替循环中对CO2的吸附和加氢的稳定性。在通常的烟气范围内（5-15%）CO2浓度的变化对综合控制单元技术的整体性能影响不大。然而，在吸附期间，O2的掺入会降低CH4的产量，并且随着氧浓度的增加，这种降低甚至会加剧。这主要是由于金属位的氧化限制了还原行为。另一方面，NOx的加入与CO2竞争碱性吸附位点，这略微限制了CO2的储存量，从而限制了CH4的产生。有益的是，该DFM在207个循环中表现出高稳定性，相当于34小时的运行时间，包括不同的CO2浓度，以及存在或不存在O2和/或NOx。结果表明，所提出的DFM配方能够在CO2吸附期间存在O2和NOx的情况下长期运行。
The Integrated Carbon Capture and Utilization-Methanation (ICCU-Methanation) requires a Dual Function Material (DFM), which firsts captures CO2 and then converts it into CH4, working in alternating adsorption and hydrogenation periods. The ICCU technology can be applied directly to a flue gas leaving a combustion chamber, which usually contains oxidizing species such as oxygen and nitrogen oxides. In this work, the stability of a DFM with composition 4%Ru-8%Na2CO3-8%CaO/Al2O3 is studied for the CO2 adsorption and hydrogenation in alternate cycles including O2 (0-10%) and NOx (0-2000 ppm) during the adsorption period. The variation of CO2 concentration in the usual range of flue gases (5-15%) has little influence on the global performance of the ICCU technology. However, the incorporation of O2 during the adsorption period decreases the production of CH4, and this decrease is even accentuated with increasing the oxygen concentration. This fact is mainly attributed to the oxidation of metal sites that limits the reduction behavior. On the other hand, the addition of NOx competes with CO2 for the basic adsorption sites, which slightly limits the amount of CO2 stored, and consequently the production of CH4. Helpfully, the proposed DFM presents high stability during the 207 cycles here performed, which corresponds to 34 h of time-on-stream, including different CO2 concentrations, and in the presence or absence of O2 and/or NOx. It is concluded that the proposed DFM formulation is competent for long-term operation in the presence of O2 and NOx during the CO2 adsorption period.