CFD intensification of coal beneficiation process in gas-solid fluidized beds

Abstract

Coal beneficiation technology using gas-solid fluidized bed is a hot topic in recent decade, however its proper design and scale-up remain a great challenge due to the very complex gas-solid flow involved. To this end, an Eulerian-Lagrangian-Lagrangian (ELL) model (Zhang et al., Renewable Energy, 2019, 136:193-201) was used to intensify the coal beneficiation process, by systematically studying the effects of particle property, operating gas velocity, initial bed height, design of gas distributor and the size of fluidized bed. It was found that (i) coal beneficiation process can be improved significantly by using coarser beneficiated coal particles, adopting smaller initial bed height (or shallow fluidized bed) and/or operating at a properly selected gas velocity, all findings indicate that the process intensification can be realized via proper selection of operating conditions; (ii) the design of gas distributor was critical for process intensification and it should be designed properly to make the gas flow as uniform as possible; and (iii) there will be no scale-up effect, if ideally uniform gas flow at the inlet can be achieved. Present study demonstrates that computational fluid dynamics is a cost-effective tool for process intensification of gas-solid fluidized beds.