The main purpose of this research was to investigate the feasibility of inc
ineration of wool-scouring sludge in a novel vertical-axis-rotating fluidis
ed bed (RFB). The experiment was carried out in a RFB with an internal diam
eter (ID) of 200 mm and height of 50 mm. A cold test was first conducted to
investigate the fluidisation performance of the RFB via parameters such as
the bubbling, gas distribution, bed shape and pressure drop. The tumbling
phenomena was observed in the bed, and this effectively enhanced the axial
mixing. The appropriate range of bed thickness, rotating speed and sand par
ticle size were identified to ensure the full fluidisation and reduce the p
article elutriation. Four wool-scouring sludges from different processes we
re incinerated in the RFB. With 5% support methane, all sludges with a maxi
mum moisture up to 70% as received could be successfully burned in the RFB
at rotating speeds of 200 and 300 rpm. The combustion was found to be inten
se with a high efficiency due to the good turbulence and mixing in the RFB.
The effects of moisture content, feeding rate and rotating speed were inve
stigated. It was found that for sludge (sample B2) with a moisture content
of 5%, the combustion could be sustained at a bed surface temperature of ar
ound 500 degreesC arid freeboard temperature of 900 degreesC without the su
pport of methane. To investigate the special advantages of swirling flow in
the RFB on the combustion and particle elutriation, a CFD model was used.
In the calculated flow field, two flow regions were identified, viz, the ou
ter free vortex region and the forced vortex flow near the axis. Recirculat
ion and turbulence of flow were generated by the pressure gradients and she
ar layers, respectively. The modelling of premixed methane and air combusti
on, which was used to simulate the volatile burning in the freeboard of the
RFB, showed two high-temperature zones near the exit and at the bottom of
the chamber near the core in accordance with the flow field. The high combu
stion efficiency was again predicted in the model, reflecting that the burn
ing was effective due to good mixing and turbulence in the RFB.