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Performance of Na2CO3-CaO sorbent in sorption-enhanced steam methane reforming
Journal of CO2 Utilization ( IF 7.2 ) Pub Date : 2021-07-08 , DOI: 10.1016/j.jcou.2021.101634
Dyovani Bruno Lima Santos 1 , Ana Caroline Pereira Oliveira 1 , Carla Eponina Hori 1
Affiliation  

The addition of alkali molten salts has been reported as a strategy to overcome the sintering problem presented by calcium oxide in CO2 capture systems. In this work, the influence of sodium doping in a CaO sorbent was investigated in the sorption enhanced steam methane reforming process (SE-SMR). The goal was to increase the stability of the sorbent and, consequently, the efficiency of the process. For that, a Na-containing sorbent was prepared using the precipitation technique and a pure calcium oxide was obtained by calcination of CaCO3. The sorbents were physically mixed with 10 % Ni/Al2O3 catalyst and tested in 10 cycles of SE-SMR at 600 °C and CH4:H2O equals to 4. In general, both materials showed 100 % of CH4 conversion and H2 molar fraction of 93.5 vol.%. However, regarding the stability over the SE-SMR cycles, it was evidenced that the addition of sodium decreased the duration of pre-breakthrough comparing with the non-doped material. The XRD, SEM, and TGA results allowed us to observe an inverse relationship of particle diameter and CO2 capture performance. Na2CO3-CaO presented a larger average crystallite size compared to the pure CaO which led to a higher probability of the CaCO3 layers to inactivate the calcium oxide and, consequently, caused a strong sintering effect. Besides the presence of sodium, the precipitation method and the synthesis conditions could have favored the low initial CO2 uptake and poor stability of the Na2CO3-CaO sorbent.



中文翻译:

Na 2 CO 3 -CaO吸附剂在吸附强化蒸汽甲烷重整中的性能

据报道,添加碱性熔盐是克服 CO 2捕集系统中氧化钙带来的烧结问题的一种策略。在这项工作中,在吸附增强蒸汽甲烷重整过程 (SE-SMR) 中研究了钠掺杂对 CaO 吸附剂的影响。目标是提高吸附剂的稳定性,从而提高过程的效率。为此,使用沉淀技术制备含钠吸附剂,并通过煅烧CaCO 3获得纯氧化钙。吸附剂与 10% Ni/Al 2 O 3催化剂物理混合,并在 600 °C 和 CH 4 :H 2 条件下进行 10 次 SE-SMR 循环测试O等于4。通常,两种材料都显示出100%的CH 4转化率和93.5 vol.%的H 2摩尔分数。然而,关于 SE-SMR 循环的稳定性,有证据表明,与非掺杂材料相比,钠的添加减少了预击穿的持续时间。XRD、SEM 和 TGA 结果使我们能够观察到粒径和 CO 2捕获性能的反比关系。与纯 CaO 相比,Na 2 CO 3 -CaO 呈现出更大的平均微晶尺寸,这导致 CaCO 3 的概率更高层使氧化钙失活,从而引起强烈的烧结效应。除了钠的存在外,沉淀方法和合成条件可能有利于Na 2 CO 3 -CaO 吸附剂的初始 CO 2吸收低和稳定性差。

更新日期:2021-07-08
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