氢溢流强化菱镁矿热解耦合逆水煤气反应研究

陆叶; 付彧; 张军

doi:10.13226/j.issn.1006-6772.GPF25020101

氢溢流强化菱镁矿热解耦合逆水煤气反应研究

Promoting dolomite pyrolysis coupled with reverse water-gas shift reaction through hydrogen spillover

摘要

摘要: 为降低耐材工业生产中菱镁矿(主要成分MgCO₃)热分解过程的能耗与碳排放，研究了菱镁矿热解耦合催化加氢的节能减碳效果，并探讨了氢溢流对该过程的强化机制。结果表明催化剂的添加对菱镁矿分解率和CO₂转化率有显著影响，尤其是对于RuNi/TiO₂/CeO₂催化剂，其在合成过程中原位形成的TiO₂可以通过调控SMSI效应促进活性组分Ni还原，增强催化剂的氢溢流效应，从而高效的将CO₂转化为CO，促进菱镁矿分解反应平衡正向移动。实现在500 ℃条件下，菱镁矿分解率达到83.17%，CO₂转化率达到55.58%，CO选择性>99%，较参比催化剂RuNi/CeO₂ (71.09%、42.36%、84.12%)有显著提升。磁选分离实验表明RuNi/TiO₂/CeO₂催化剂可以与固态产物有效分离，回收率大于95%。原位DRIFTS表征发现*COOH物种是该过程的关键中间体，其进一步解离为CO。

Abstract: Abstract: To reduce energy consumption and carbon emissions during the thermal decomposition of magnesite （primarily composed of MgCO₃） in the production of refractory materials, the energy-saving and carbon-reducing effects of coupling magnesite pyrolysis with catalytic hydrogenation were investigated. Additionally, the role of hydrogen spillover in enhancing this process was explored. The results demonstrated that the addition of a catalyst had a significant impact on both magnesite decomposition and CO₂ conversion, particularly with the RuNi/TiO₂/CeO₂ catalyst. The TiO₂ that form in situ during the synthesis process can enhance hydrogen spillover, which efficiently converts CO₂ into CO and helps shift the magnesite decomposition equilibrium to the forward direction. Under conditions of 500 ℃, the decomposition of magnesite reached 83.17%, CO₂ conversion reached 55.58%, and CO selectivity exceeded 99%, showing a notable improvement over the reference catalyst RuNi/CeO₂ （71.09%, 42.36%, 84.12%）. Magnetic separation experiments confirmed that the RuNi/TiO₂/CeO₂ catalyst could be effectively separated from the solid products, with a recovery rate of over 95%. In situ DRIFTS characterization revealed that *COOH species are key intermediates, which further dissociate into CO.

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