Copper-Decorated Hematite as an Oxygen Carrier for in Situ Gasification Chemical Looping Combustion of Coal

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• 作者：Weijing Yang ; Haibo Zhao ; Jinchen Ma ; Daofeng Mei ; Chuguang Zheng
• 刊名：Energy & Fuels
• 出版年：2014
• 出版时间：June 19, 2014
• 年：2014
• 卷：28
• 期：6
• 页码：3970-3981
• 全文大小：818K
• 年卷期：v.28,no.6(June 19, 2014)
• ISSN：1520-5029

文摘

Iron ore is a cheap and nontoxic oxygen carrier in chemical looping combustion (CLC) systems. However, iron ore exhibits low reactivity with solid fuels. In this work, hematite decorated with Cu via impregnation was used as an oxygen carrier. Experiments were conducted in a batch fluidized bed reactor using Shenhua (SH) bituminous coal and Gaoping (GP) anthracite as fuels. The effects of Cu loading in the hematite, reaction temperature, supply oxygen coefficient, and coal type on the CLC performance of coal were investigated. It was found that hematite loaded with 6% Cu (6CuHem) had better reactivity with the gasification products (CO and H₂) of coal than hematite (Hem) alone. Furthermore, 6CuHem was found to accelerate the gasification rate of GP anthracite char. A reaction temperature higher than 900 掳C was conducive to fast and complete conversion of carbon in coal. As the supply oxygen coefficient was increased, the rate of carbon conversion and the combustion efficiency of coal increased. Multiple redox cycles were performed to study the stability of these oxygen carriers. It was found that the reactivity of 6CuHem was mostly stable after three redox cycles. SEM-EDX analysis revealed a shell enriched with copper on the outside of fresh 6CuHem particles. After 29 cycles, the shell nearly disappeared, and the copper content on particle鈥檚 surface was decreased due to surface abrasion and migration of copper toward the internal part of the particle.