Influence of vertical heat exchanger tubes, their arrangement and the column diameter on the hydrodynamics in a gas–solid bubbling fluidized bed

Abstract

The hydrodynamic behavior of a cold-flow gas–solid fluidized bed with an inner diameter of 22 cm is investigated by means of an ultra-fast X-ray tomographic setup. In the case of an exothermal reaction, heat exchanger tubes are required to remove the reaction heat out of the bubbling fluidized bed reactor. For the examined cold-flow model, the heat exchanger tubes are replaced by vertical internals that serve as placeholder. The influence of vertical internals on the bubble properties for different spatial configurations (square and circular arrangements) is investigated in addition to measurements without internals. Furthermore, the hydrodynamic results of the Ø 22 cm column are compared with an available data set which is based on measurements that were conducted in a column with an inner diameter of 14 cm. The objective of this paper is to provide measurement data for the scale-up process as well as for various computer models simulating a bubbling fluidized bed with vertical internals. It was found that the scale-up process from pilot plants to an industrial scale may be simplified if vertical internals are present, independently of the geometric arrangement.