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.