CH_4化学链燃烧串行流化床连续实验研究

Continuous Operation of Interconnected Fluidized Bed Reactor for Chemical Looping Combustion of CH_4

在新设计的串行流化床反应器系统中,采用天然赤铁矿作为氧载体进行了连续CH_4化学链燃烧实验.研究了在不同反应温度(900,℃、950,℃、1,000,℃)、不同热功率(1.00,k Wth、1.25,k Wth、1.50,k Wth)时燃料反应器对CH_4转化率及CO_2气产率的影响.对新鲜和反应后的赤铁矿氧载体的比表面积(BET)、扫描电子显微镜(SEM)和X-射线衍射仪(XRD)的表征测试表明:表面轻微的烧结和磨损导致使用过的氧载体比表面积有所下降;氧载体仍保持多孔结构,有利于其与燃料气体之间的充分接触和反应;氧载体颗粒之间没有团聚现象.对新鲜样品和连续运行100,h后的样品在TGA上进行载氧能力测试,结果表明,连续运行100,h后的氧载体载氧能力保持良好.CH_4化学链燃烧串行流化床连续运行实验验证了反应器设计和运行的可行性,同时也证明该种赤铁矿是实现化学链燃烧比较理想的氧载体.

Chemical looping combustion （CLC） is a novel technology for CO2 capture with low energy cost and high efficiency. In the newly-designed interconnected fluidized bed reactors, natural hematite was continuously tested as oxygen carrier and CH4 as fuel. The effects of operational parameters, such as operational temperature （900 ℃, 950 ℃ and 1 000 ℃）, and thermal power（1.00kWth, 1.25 kWth and 1.50 kWth） , on CH4 conversion and CO2 yield were investigated. Fresh and used oxygen carriers were observed by specific surface area （BET）, scanning electron microscope （SEM） and X-ray diffraction（XRD）, which showedthat the BET surface ofused sample decreased due to slight sintering and attrition on the surface. However, the porous structure on the oxygen carrier ensures a sufficient contact between oxygen carrier and CH4. No agglomeration of used particles was observed. The thermogravimetric analysis results of used samples showed that the oxygen carrier maintained good reactivity. The feasibility of reactor design and operation was verified by the continuous operation of interconnected fluidized bed. At last, the hematite was proved to be a good choice as oxygen carrier.