串行流化床内气体串混特性

Gas leakage properties of chemical looping combustion in interconnected fluidized bed

串行流化床反应器间的气体串混是影响化学链燃烧过程的关键因素之一,采用串行流化床冷态试验装置,通过改变各反应器入口流化数,考察反应器间的串混量及串混率。反应器之间的气体串混路径可能有空气反应器和燃料反应器之间的气体串混、燃料反应器内气体向旋风分离器串混、隔离器气体在空气反应器和燃料反应器内的分布。结果表明,在空气反应器和燃料反应器之间加设隔离器能有效阻止两个反应器之间发生气体串混;燃料反应器内少许气体通过反应器内料腿向上串混到旋风分离器排气中,串混率约为2%,这使得该串行流化床化学链燃烧的理论碳捕集效率可以达到98%;燃料反应器流化风速对隔离器内气体在两个反应器的分布影响较小,采用水蒸气流化可避免隔离器气体向空气反应器和燃料反应器内串混所带来的影响。

Chemical looping combustion（CLC）is an efficient technology with inherent separation of greenhouse gas CO2.The gas leakage between reactors is an important factor for CLC.Gas leakage was experimentally investigated in an interconnected fluidized bed reactor.There were several possible routes for gas leakage in the reactors：from air reactor（AR）to fuel reactor（FR）and from FR to AR,from FR to cyclone（CL）,from loopseal（LPS）to AR and from LPS to FR.The leakage was measured according to different fluidization numbers of AR,FR and LPS.The experimental results demonstrated that the gas leakage between AR and FR could be effectively prevented by adding a LPS between them.A little gas leakage from FR to cyclone was through the downcomer,and the ratio of gas leakage was about 2%,making carbon capture efficiency as high as 98%.The fluidizing velocity of FR had much less effect on the distribution of gas leakage in the two reactors.Moreover,the influence of gas leakage could be prevented by using steam as fluidizing agent.