(696e) Gas-Solid Flow Hydrodynamics Characteristics in a Circulating Fluidized Bed Riser with External Heat Exchanger

To investigate the gas-solids flow hydrodynamics characteristics in a cold circulating fluidized bed (CFB) loop with external heat exchanger (EHE), electrical capacitance tomography (ECT) and pressure sensor are used to measure the solids concentration and split-flow rates in the EHE with a new type of ash-controlled valve. The CFB facility includes the riser, cyclone separator, external heat exchanger chamber with heating surface and chamber without heating surface.  Two ECT sensors with eight electrodes were mounted in the pneumatic pipe between the controlled valve and the EHE. The experiment results indicate that the split-flow rates increase linearly with the increase of the opening of the controlled valve. The solid flow rate from the EHE to the CFB riser is increased with the increase of the fluidization air flow rate in the chamber with heating surface. The increase of the air flow rate in the chamber without heating surface will enhance the transportation of the solids from the chamber without heating surface to the chamber with heating surface. The test results for solids flow and regulating characteristics provide useful information for CFB boiler with EHE.