Solid flux measurement in dual fluidized bed processes based on solid samples

Chemical looping gasification is a novel dual fluidized bed technology for the conversion of solid feedstock to a nitrogen-free syngas without the need of pure oxygen. Recently, a pilot plant has been erected to advance chemical looping gasification towards autothermal operation. For autothermal operation, the solids flux between the two reactors becomes important, as it transports the required sensible heat in addition to the oxygen required for the process. As a reliable method to accurately measure the solids flux under process conditions currently does not exist, a method has been devised to measure the solid circulation for dual fluidized bed systems and tested utilizing the process specifics of chemical looping gasification to allow for calibration of online measurement equipment without opening the reactor system. This method utilizes solid samples from coupling elements to calculate the solids flux in chemical looping gasification with an overall uncertainty smaller than 20%.