Boosting the Conversion of CO2 with Biochar to Clean CO in an Atmospheric Plasmatron: A Synergy of Plasma Chemistry and Thermochemistry
Boosting the Conversion of CO2 with Biochar to Clean CO in an Atmospheric Plasmatron: A Synergy of Plasma Chemistry and Thermochemistry
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DOI：
10.1021/acssuschemeng.2c01778
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发表时间：
2022-05
期刊：
影响因子：
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通讯作者：
Hao Zhang;Qinhuai Tan;Qun-xing Huang;Kaiyi Wang;X. Tu;X. Zhao;Chunfei Wu;Jian-hua Yan;
中科院分区：
文献类型：
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作者：
Hao Zhang;Qinhuai Tan;Qun-xing Huang;Kaiyi Wang;X. Tu;X. Zhao;Chunfei Wu;Jian-hua Yan;
在这项工作中，CO2转化为无O2的CO已被研究在常压等离子体通过反应与生物炭。在不同进料流量下，考察了生物炭来源、热解温度、气固反应方式（固定床和流化床）对反应性能的影响。利用原位发射光谱法探讨了CO2转化的基本机制，重点是了解等离子体化学和热化学在CO2转化中的作用。结果表明，生物质炭和等离子体的共同存在显著促进了CO2的转化。与热CO2裂解相比，等离子体CO2+ C工艺显著提高了CO2转化率，从0提高到27.1%。在较高热解温度下制备的核桃壳生物炭由于碳含量较高，有利于CO2转化。令人惊讶的是，固定床提供了比流化床更好的CO2+ C反应性能，受益于生物炭迅速消耗所产生的O2。在等离子体管（1015 cm-3）中实现的高电子密度允许高处理能力，并且获得的具有增强的振动能量（6300-8200 K）的中等电子温度（1.1-1.5 eV）通过振动激发激发最有效的CO2活化路线。在核心等离子体区域（2100-2400 K）和气-固反应区域（<1573 K）中的相对高的旋转（气体）温度通过热化学分别间接地驱动CO2分解的逆反应并且有利地促进生物炭涉及的反应。等离子体化学主导的CO2解离和热化学主导的CO2+ C和O2+ C反应的协同作用解释了在等离子体CO2+ C过程中获得的高CO2转化率。该研究为等离子体化学和热化学耦合高效转化CO2提供了一条新途径。
In this work, the conversion of CO2into O2-free CO has been investigated in an atmospheric plasmatron via the reaction with biochar. The effects of the biochar source, pyrolysis temperature for biochar preparation, and gas–solid reaction patterns (fixed bed and fluidized bed) on the reaction performance were evaluated under different feed flow rates. The underlying mechanisms were explored usingin situoptical emission spectroscopy focusing on understanding the role of plasma chemistry and thermochemistry in CO2conversion. The results revealed that the presence of both biochar and plasma significantly facilitate CO2conversion. In comparison to thermal CO2splitting, the plasmatron CO2+ C process dramatically enhanced the CO2conversion from 0 to 27.1%. Walnut shell biochar prepared at relatively high pyrolysis temperatures favored CO2conversion due to a high carbon content. A fixed bed surprisingly provided remarkably better performance than a fluidized bed for the CO2+ C reaction, benefiting from a prompt consumption of the generated O2by biochar. The high electron density achieved in the plasmatron (1015cm–3) allows for a high processing capacity, and the moderate electron temperature (1.1–1.5 eV) with enhanced vibrational energy (6300–8200 K) obtained stimulates the most efficient CO2activation routes through vibrational excitation. The relatively high rotational (gas) temperatures in the core plasma area (2100–2400 K) and in the gas–solid reaction region (<1573 K) detrimentally drive the reverse reactions of CO2splitting and advantageously boost the biochar-involved reactions, respectively, by thermochemistry. The synergy of plasma-chemistry-dominated CO2dissociation and the thermochemistry-dominated CO2+ C and O2+ C reactions accounts for the high CO2conversion obtained in the plasmatron CO2+ C process. The immediate study provides a novel route for efficient CO2conversion by coupling plasma chemistry and thermochemistry.