The analysis of the shed thickness was carried out in a made of Plexi-glas. Figure
a)
Figure 2-1. a) Fluidized bed apparatus components and instrumentation: Blower (1), air by-pass (2), orifice plate for flow measurement (3), wind box (4), air distributor (5), radioactive tracer-agglomerate
(9), 1.3 m of disengagement section (10), cyclone (11), fine powder collect
(12), shed (13). b) Schematic of the conical section of the fluidized bed with the single shed plus six layers of simulated foulant on top of it.
Four kilograms of fluid coke provided by Syncrude Canada, LTD, was fluidized material [particle density ranges from 1440 and 1520 kg/
Soundararajan, 2001], with Sauter mean diameter of 98
Experimental Technique and its Accuracy
ioactive Particle Tracking technique applied to fluidized beds consists of detecting the amount of radiation in the form of γ-rays, emitted by a single radioactive
. The radiation of a tracer-agglomerate is detected by an array of scintillation detectors surrounding the vessel. The signal from each detector is proportional to the distance between the tracer-agglomerate and the detector. At least tracer-agglomerate location is estimated by analyzing the signals coming from all detectors.
ental Setup
The analysis of the shed thickness was carried out in a bubbling fluidized bed Figure 2-1-A, presents the schematics of the apparatus.
b)
Fluidized bed apparatus components and instrumentation: Blower (1), air pass (2), orifice plate for flow measurement (3), wind box (4), air distributor (5), agglomerate (6), NaI scintillation sensors (7), USB hub (8), computer (9), 1.3 m of disengagement section (10), cyclone (11), fine powder collect
) Schematic of the conical section of the fluidized bed with the single hed plus six layers of simulated foulant on top of it.
Four kilograms of fluid coke provided by Syncrude Canada, LTD, was particle density ranges from 1440 and 1520 kg/m3 (
, with Sauter mean diameter of 98 µm [obtained using a Mastersizer
Experimental Technique and its Accuracy
technique applied to fluidized beds consists of rays, emitted by a single radioactive is detected by an array of ng the vessel. The signal from each detector is d the detector. At least location is estimated by analyzing the signals
bubbling fluidized bed A, presents the schematics of the apparatus.
Fluidized bed apparatus components and instrumentation: Blower (1), air pass (2), orifice plate for flow measurement (3), wind box (4), air distributor (5), (6), NaI scintillation sensors (7), USB hub (8), computer (9), 1.3 m of disengagement section (10), cyclone (11), fine powder collector recipient ) Schematic of the conical section of the fluidized bed with the single
Four kilograms of fluid coke provided by Syncrude Canada, LTD, was used as the (Furimsky, 2000; m [obtained using a Mastersizer
S-series Long Bench (Malvern, Worcestershire, UK)]. Fluid coke particles fall in between type A and B particles in the Geldart classification (Geldart, 1973; Song et al., 2006). A 1.63 mm diameter, Epoxy/Gold (E/G) trace
kg/m3 (type D in the Geldart classification of particles), was selected for this test. It is very clear that the tracer
fluidized bed material (coke); this results in locating the bottom-zone of the fluidized b
going to be shown in the results section.
Figure 2-2. Schematic of the single shed structure with variable thicknesses of simulated
foulant in the observation space. The height has a value of 8.5 cm divided in sections of 0.5 cm, which are 19 divisions.
A single tracer-agglomerate
superficial air velocity of 0.38 m/s at the distributor and 0.09 m/s in the upper sect the bed; the Industrial Fluid
al., 2006). Eight experiments with different shed conducted; 250,000 tracer
A 4 cm by 4 cm,
shed and foulant simulation material as presented in
series Long Bench (Malvern, Worcestershire, UK)]. Fluid coke particles fall in between type A and B particles in the Geldart classification (Geldart, 1973; Song et al.,
iameter, Epoxy/Gold (E/G) trace-particle with a density of 2300 (type D in the Geldart classification of particles), was selected for this test. It is tracer-agglomerate of Epoxy/Gold is bigger and denser than the terial (coke); this results in locating the tracer-agglomerate
zone of the fluidized bed with much more frequency than in the upper zones, as is going to be shown in the results section.
Schematic of the single shed structure with variable thicknesses of simulated foulant in the observation space. The height has a value of 8.5 cm divided in sections of 0.5 cm, which are 19 divisions.
agglomerate was introduced into the conical fluidized bed with a superficial air velocity of 0.38 m/s at the distributor and 0.09 m/s in the upper sect
luid Cokers run with a superficial gas velocity of 0.24 m/s (Cui et t experiments with different shed thicknesses Figure
tracer-agglomerate coordinates were obtained for each experiment. A 4 cm by 4 cm, 0.7 cm thick 90 degree angle plywood profile was used as the shed and foulant simulation material as presented in Figure 2-2. The characteristics of the series Long Bench (Malvern, Worcestershire, UK)]. Fluid coke particles fall in- between type A and B particles in the Geldart classification (Geldart, 1973; Song et al.,
particle with a density of 2300 (type D in the Geldart classification of particles), was selected for this test. It is of Epoxy/Gold is bigger and denser than the agglomerate at the in the upper zones, as is
Schematic of the single shed structure with variable thicknesses of simulated foulant in the observation space. The height has a value of 8.5 cm divided in sections of
was introduced into the conical fluidized bed with a superficial air velocity of 0.38 m/s at the distributor and 0.09 m/s in the upper section of okers run with a superficial gas velocity of 0.24 m/s (Cui et Figure 2-1-B were coordinates were obtained for each experiment. 0.7 cm thick 90 degree angle plywood profile was used as the
eight experiments are described in Table 2.1. At the beginning of the eight experiments, the tracer particle had a radiation of 41,880 Bq (measured by putting the tracer 5 cm away from one of the scintillation detectors) and at the end; it was estimated at 25,015 Bq. The RPT technique using a single computer, presents detectors saturation with a tracer-agglomerate radiation above 45,000 Bq.
Table 2.1. Description of the eight experiments used for evaluating the RPT technique in
detecting the amount of fouling that a shed has. Experiment
Number Description
Height of Foulant from the Shed Surface
1 Shed. 0 cm
2 Shed plus 1 cm of thickness. 1 cm
3 Shed plus 2 cm of thickness. 2 cm
4 Shed plus 3 cm of thickness. 3 cm
5 Shed plus 4 cm of thickness. 4 cm
6 Shed plus 5 cm of thickness. 5 cm
7 Shed plus 6 cm of thickness. 6 cm
8 No internals inside the vessel. None