Performance of Large Scale Prepared Iron-Based Oxygen Carrier

Performance of Large Scale Prepared iron-Based Oxygen Carrier

Ren tian, An Mei, Hu xiude, Guo Qingjie^*

£¨State key laboratory of high-efficiency utilization of coal and green chemical engineering, Ningxia university, yinchuan 750021, China)

Abstract: To screen the low-cost and high-efficient oxygen carrier£¨OC£© that is suitable for coal chemical-looping gasification process, the natural hematite mixed cement, attapulgite (ATP) and bentonite were modified by mechanical mixing grinding ball method, and coal chemical-looping gasification experiments were carried out on the fluidized bed to investigate the redox and cyclic reactivity of modified oxygen carriers. Brunauer Emmett Teller (BET), scanning electron microscope (SEM) and X-ray diffraction (XRD) were used to characterize both fresh and used oxygen carrier particles. The results show that the reactivity order of iron-based composite oxygen carrier with different modifiers was as follow Fe@ATP>Fe@cemenct>Fe@bentonite at 950℃. The addition of cement effectively promotes the water-gas shift reaction, leading to the decrease of CO fraction and the increase of H₂ fraction in coal gasification products. The surface area and attrition resistance of Fe₂O₃/ATP OCs are improved significantly by using ATP as the support. Owing the synergy between ATP and Fe₂O_3, both are catalytic active, carbon conversion is enhanced significantly£®During the multiple cycles of experiments, the composition of the syngas remained stable and the sintering of the surface of the oxygen carriers resulted in a decrease in specific surface area and void volume. However, the particles kept a porous structure facilitating reactions between reactant gases and oxygen carrier particles Therefore, the compound iron oxygen carrier Fe@ATP is appropriate to be used for industrial production.

Key words: mechanical mixing grinding ball method; chemical-looping gasification; coal; oxygen carrier; hematite