Bed-inventory overturn mechanism for pant-leg circulating fluidized bed boilers

► A model was established to study the overturn mechanism for a pant-leg CFB riser. ► High particle volume ratio along the central plane of CFB enhances the overturn. ► A self-balance ability exists for the pant-leg CFB, though it is relatively slow. ► The performance curve of the primary air supply is very critical to the overturn.