Materials science

Freeboard

Char

Pyrolysis

Physics

Nuclear engineering

Mechanics

Environmental science

Coal

Fluidization

Pellets

Waste management

Engineering

Wood gas generator

Composite material

Fluidized bed

Fuel

Gas-solid fluidized beds play an important role in many industrial operations. However, there still is a lack of knowledge concerning the processes inside the bed, which impedes proper designing and upscaling of fluidized bed reactors. In this work, biomass steam gasification in a fluidized bed reactor is investigated with a coarse-grained CFD-DEM approach. The numerical model in the Eulerian-Lagrangian framework treats the gas phase as a continuum and describes the particle interactions with the discrete element method (DEM). The non-spherical shape of the particles is accounted for in the momentum exchange calculation with the gas phase. The considered systems consist of steam as the fluidization gas, entering the bottom region of the three dimensional reactor geometry through inclined nozzles in an inner duct at the center axis. The wood pellets are fed into the reactor from the top of the freeboard together with a nitrogen purge gas stream. Over time, different operation modes occur, since there is no sol...

Coarse-grained CFD-DEM simulation of biomass gasification in a fluidized bed reactor