As the typical pollutants from marine LNG engines, CH4 and NOx can be addressed simultaneously through the nonthermal plasma-catalyst method. To reveal the mechanism behind the plasma-catalyst removal of CH4 and NOx, an experimental and chemical kinetic study was performed under the LNG engine exhaust environment. Specifically, a plasma-catalyst experiment was performed over the newly designed combined catalyst Cr-In/SSZ-13+Co/SSZ-13, and influences of temperatures, specific energy inputs (SEIs) and inlet concentrations of species on removal efficiencies of CH4 and NOx were analyzed. On this basis, a catalyst chemistry model for CH4-NOx was developed and optimized considering the interaction between CH4 and NOx and the impacts of species from the plasma on the catalyst. Then a plasma-catalyst kinetic model of CH4-NOx was proposed by integrating the developed catalyst chemistry model with our previous plasma model, and its good performance was validated against the newly obtained experimental values at the concerned conditions. Finally, a kinetic analysis was conducted to understand the evolution mechanism of CH4 and NOx in the plasms-catalyst process. The result shows that as SEIs increased, up to 60 % of CH4 was converted to CO in the plasma reactor, with 77 % of CH4 and all CO converted to CO2 in the catalytic reactor. For NOx, additional NOx was produced through N oxidation. Then in the subsequent catalytic reactor, NO was oxidized to NO2, which then was reduced to N2 by CH4. In addition, the conversion of CH4 to CO in the plasma reactor inhibited NO catalytic oxidation.

中文翻译：

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深入了解船用 LNG 发动机排气条件下 CH4-NOx 的等离子体催化剂去除过程：实验和化学动力学


作为船用 LNG 发动机的典型污染物，CH4 和 NOx 可以通过非热等离子体催化剂方法同时处理。为了揭示等离子体催化剂去除 CH4 和 NOx 背后的机制，在 LNG 发动机排气环境下进行了实验和化学动力学研究。具体来说，对新设计的复合催化剂 Cr-In/SSZ-13+Co/SSZ-13 进行了等离子体催化剂实验，分析了温度、物质比能量输入 （SEI） 和入口浓度对 CH4 和 NOx 去除效率的影响。在此基础上，考虑到 CH4 和 NOx 之间的相互作用以及等离子体中物质对催化剂的影响，开发并优化了 CH4-NOx 的催化剂化学模型。然后，通过将开发的催化剂化学模型与我们以前的等离子体模型相结合，提出了 CH4-NOx 的等离子体-催化剂动力学模型，并在相关条件下根据新获得的实验值验证了其良好的性能。最后，进行了动力学分析以了解 CH4 和 NOx 在等离子体催化剂过程中的演化机制。结果表明，随着 SEI 的增加，高达 60% 的 CH4 在等离子体反应器中转化为 CO，77% 的 CH4 和所有 CO 在催化反应器中转化为 CO2。对于 NOx，通过 N 氧化产生额外的 NOx。然后在随后的催化反应器中，NO 被氧化成 NO2，然后被 CH4 还原成 N2。此外，等离子体反应器中 CH4 转化为 CO 抑制了 NO 催化氧化。