88
C. Neugebauer et al.
comprehensive knowledge about the transport behavior of gas-solids flows, especially at high solids loading.
4 Experimental Studies on Continuous Spray Granulation
in Horizontal Fluidized Beds
4.1 Experimental Setup
The experiments have been carried out in a pilot-scale horizontal fluidized bed plant
(Fig. 12; ProCell 25, Glatt Ingenieurtechnik GmbH Weimar, Germany). Combined
with an external pneumatic conveying and a screening-milling cycle, this process
was operated continuously.
The process chamber, presented in Fig. 12a, has a length of 1 m, a width of 0.25 m
and a height of about 0.40 m and can be divided into four different compartments
by introducing weirs. The aim was to analyze the influence of thermal conditions
on product quality. The process conditions in every stage were the same, operated
with constant inlet gas velocity of 3 m/s. The solution was injected by four two-fluid
nozzles in bottom-spray configuration (see Fig. 12b). Atomization was supported
by compressed air. The spray solution consisted of 35 wt.-% of sodium benzoate
dissolved in demineralized water. The hold-up material consisted of sodium benzoate
particles in a size range of 0.5 m to 2.5 mm (undersize, product and oversize material)
and an apparent density of 1440 kg/m
3 .
Nuclei were exclusively produced by grinding of oversized material in a pin mill.
Hence, no external feed of solid material was required in these experiments. The
process was operated with a constant bed mass of 25 kg, while starting with a bed
that contained 50 wt% product particles, 25 wt% oversized and 25 wt% undersized
particles.
The thermal conditions of the spray granulation process can be varied, not only
changing the process temperature, but also by changing the spray rate of the solution.
For this reason, those two parameters, given in Table 6, have been selected as variables
in the experiments.
During the experiments samples were taken from the process chamber for an offline measurement of the moisture content of the solid material and for tracking the
Table 6 Parameter variations to investigate the influence of the thermal conditions on product
properties [1]
Parameter
Values
Gas inlet temperature
( ◦ C)
100
150
200
Spray rate (kg/h)
40
80
120
C. Neugebauer et al.
comprehensive knowledge about the transport behavior of gas-solids flows, especially at high solids loading.
4 Experimental Studies on Continuous Spray Granulation
in Horizontal Fluidized Beds
4.1 Experimental Setup
The experiments have been carried out in a pilot-scale horizontal fluidized bed plant
(Fig. 12; ProCell 25, Glatt Ingenieurtechnik GmbH Weimar, Germany). Combined
with an external pneumatic conveying and a screening-milling cycle, this process
was operated continuously.
The process chamber, presented in Fig. 12a, has a length of 1 m, a width of 0.25 m
and a height of about 0.40 m and can be divided into four different compartments
by introducing weirs. The aim was to analyze the influence of thermal conditions
on product quality. The process conditions in every stage were the same, operated
with constant inlet gas velocity of 3 m/s. The solution was injected by four two-fluid
nozzles in bottom-spray configuration (see Fig. 12b). Atomization was supported
by compressed air. The spray solution consisted of 35 wt.-% of sodium benzoate
dissolved in demineralized water. The hold-up material consisted of sodium benzoate
particles in a size range of 0.5 m to 2.5 mm (undersize, product and oversize material)
and an apparent density of 1440 kg/m
3 .
Nuclei were exclusively produced by grinding of oversized material in a pin mill.
Hence, no external feed of solid material was required in these experiments. The
process was operated with a constant bed mass of 25 kg, while starting with a bed
that contained 50 wt% product particles, 25 wt% oversized and 25 wt% undersized
particles.
The thermal conditions of the spray granulation process can be varied, not only
changing the process temperature, but also by changing the spray rate of the solution.
For this reason, those two parameters, given in Table 6, have been selected as variables
in the experiments.
During the experiments samples were taken from the process chamber for an offline measurement of the moisture content of the solid material and for tracking the
Table 6 Parameter variations to investigate the influence of the thermal conditions on product
properties [1]
Parameter
Values
Gas inlet temperature
( ◦ C)
100
150
200
Spray rate (kg/h)
40
80
120