Pressurized oxy-combustion is a promising technology for carbon capture, utilization, and storage. For the captured CO₂ to be used for enhanced oil recovery or stored in geological formations, flue gas impurities, including residual O₂ in the CO₂ stream, must be purified to meet the purity specifications. A catalytic approach to reducing residual O₂ with CH₄ was investigated in this study. Five CoMn- and Cu-based catalysts were synthesized or acquired, and a reverse-flow fixed-bed reactor was used to assess their performance for O₂ removal from a simulated oxy-combustion flue gas at 15 bar. The impacts of the operating parameters on O₂ removal, such as temperature, gas hourly space velocity, O₂/CH₄ ratio, and gas pressure, were investigated. Among the tested catalysts, the two CoMn catalysts were superior in both activity and selectivity, with the reaction lighting off at about 350 °C and achieving 99% O₂ removal at about 500 °C. The kinetics of the catalytic reaction is discussed, and the Mars–van Krevelen redox mechanism is deemed valid for describing the reaction pathway for the top-performing CoMn catalysts. The catalytic reaction was determined to be first order in CH₄ and zero order in O₂ under the test conditions.

中文翻译：

---

高效催化还原残留氧气，以净化高压氧气燃烧系统中的二氧化碳流

加压氧燃烧是一种用于碳捕获，利用和储存的有前途的技术。为了将捕获的CO ₂用于提高石油采收率或将其存储在地质构造中，烟道气杂质（包括CO ₂流中残留的O _2）必须进行净化，以满足纯度要求。在这项研究中研究了一种用CH ₄还原残留O _2的催化方法。合成或获得了五种基于CoMn和Cu的催化剂，并使用逆流固定床反应器评估了它们在15 bar下从模拟的氧燃烧烟道气中去除O ₂的性能。操作参数对O _2的影响研究了温度，气体时空速度，O ₂ / CH ₄比和气体压力等去除率。在所测试的催化剂中，两种CoMn催化剂在活性和选择性上均优异，反应在约350°C时熄灭，在约500°C时达到99％的O ₂去除率。讨论了催化反应的动力学，并且认为Mars-van Krevelen氧化还原机理对于描述性能最佳的CoMn催化剂的反应途径是有效的。在测试条件下，确定催化反应在CH _4中为一级，在O _2中为零级。