Influence of Distributed Secondary Gas Injection on the Performance of a Bubbling Fluidized-Bed Reactor

Distributed secondary gas injection via a fractal injector was studied in a lab-scale 3-D fluidized bed to determine its effect on bubble size, bubble fraction, residence time, mixing, and conversion. The experimental results indicate improved reactor performance and are consistent with earlier work in 2-D beds. A model was developed based on simple two-phase theory that describes the effect of distributed secondary injection on the performance of ozone decomposition in a bubbling fluidized bed. The model was used to predict the performance of a reactor for the production of maleic anhydride from n-butane, which includes consecutive and side reactions. The results showed that the production and selectivity of maleic anhydride were significantly improved. It can be concluded that distributed secondary gas injection improves the mass transfer and gas-solid contact, which results in increased reactor performance. It likely achieves these improvements by enhanced gas flow through the dense phase and more micromixing around the injection points, which causes greater interaction between the phases. Some aspects of applying this technology in industry are discussed. © 2008 American Chemical Society.