rotating uidized bed combustor as shown schematically in
Figure 1. The combustor consists of an outer cylindrical
vessel 260 mm ID, which acts as a gas manifold to the
co-axial 200 mm ID and 40 mm high distributor cylinder.
The stainless steel distributor is 5 mm thick with an open
area of 1% made of uniformly distributed 1 mm holes. The
upper and the bottom ends are covered with mild steel
plates, insulated with refractory Kaowool paper. The upper
end wall includes a central outlet opening which forms the
exhaust duct. The upper and lower plates con. ning the bed
are water manifolds interconnected by six water cooling
tubes 27 mm OD, immersed longitudinally in the bed. The
whole assembly including the outer cylinder vessel is
rotated about its vertical axis by means of a hollow drive
shaft connected to a variable speed motor capable of speeds
up to 1000 rpm (100 g-loading).
Air was supplied by a compressor and metered by a
rotameter before being fed into the bed through the hollow
shaft leading into the outer cylinder, from where it was
injected into the bed through the distributor cylinder. The
pressure drop across both the bed and the air distributor
cylinder was measured using a water manometer. The bed
was equipped with three chromel/alumel (Type-K) thermocouples
protruding 2 mm away from the distributor cylinder,
positioned at different heights inside the bed and connected
via a rotating slip ring assembly to the display instruments.
The temperature of the bed surface was measured using a
thermocouple attached to the feeding tube (the thermocouple
tip was 20 mm away from the tube end). The
temperature of the ue gas was measured using a
thermocouple positioned at the exit of the exhaust duct.
The temperatures of the bed near the distributor at the
middle height (Tb), the bed surface (Ts) and the ue gas (Tf )
were continuously recorded using a chart recorder.
A stainless steel probe positioned at the exit duct was
used to extract a sample of the ue gas. The gas sample was
passed through a glass wool . lter, a water cooled heat
exchanger, and a drier consisting of calcium chloride
granules before entering on-line gas analysers. O2 was
measured based on the paramagnetic effect while CO and
CO2 were measured using non-dispersive infrared absorption
spectrometry analysers. The measurement signals were
shown on-line and continuously recorded using a chart
recorder.