Fluidized bed granulation
A fluidized bed granulator comprising one or more compartments with a floor with openings for the supply of a fluidization medium and a plurality of sprayers. The sprayers are connected to a supply of a granulating liquid and are configured to spray the liquid in one or more spraying zones next to one or more unsprayed zones of the fluidized bed.
1. A fluidized bed granulator comprising a compartment with walls and a floor with an inlet for nuclei, the floor having a plurality of openings for a supply of a fluidization medium and a plurality of individual sprayers connected to a supply of a granulating liquid, the sprayers being arranged at spaced apart positions on the floor, wherein the sprayers are configured to spray the granulating liquid in one or more parallel linear spraying zones extending over the floor between a first wall and a second wall alternating with one or more unsprayed zones of the fluidized bed granulator and wherein the sprayers are arranged in clusters.
2. The granulator according to claim 1 wherein the sprayers are spaced at uneven distances from each other.
3. The granulator according to claim 2 wherein the shortest distance between adjacent sprayers in a cluster is less than the shortest distance between two adjacent clusters.
4. The granulator according to claim 1 wherein a distance between parallel clusters is about 0.4-1 meter.
5. The granulator according to claim 3 , wherein the distance between sprayers in a cluster is about 0.1-0.4 meter.
6. The granulator according to claim 3 , wherein for at least a part of the sprayers the distance between clusters is about 2-3 times the distance between sprayers within a cluster.
7. The granulator according to claim 1 wherein a sprayer density in the compartment is at least 7 sprayers per m 2 , whereas a density per cluster of sprayers is at least 25 sprayers per m 2 .
8. The granulator according to claim 7 wherein the compartment has a sprayer density of at least 9 sprayers per m 2 whereas the density per cluster of sprayers in the compartment is at least 29 sprayers per m 2 .
9. The granulator according to claim 1 wherein the floor is a grid floor.
10. The granulator according to claim 1 , wherein an outlet of the granulator opens into an aftercooler.
11. The granulator according to claim 10 wherein the aftercooler is a fluidized bed cooler.
12. The granulator according to claim 7 and further comprising a second compartment configured to receive nuclei from the compartment and to provide nuclei for discharge through an outlet, the second compartment having a second plurality of openings for a supply of the fluidization medium and a second plurality of sprayers connected to the supply of the granulating liquid, wherein the second plurality of sprayers are configured to spray the granulating liquid in the second compartment in one or more spraying zones next to one or more unsprayed zones, wherein the second plurality of sprayers are arranged in clusters and wherein the clusters are parallel clusters extending in a flow direction for nuclei.
13. The granulator according to claim 12 wherein a sprayer density of the second plurality of sprayers is at least 7 sprayers per m 2 , whereas the density per cluster of sprayers of the second plurality of sprayers is at least 25 sprayers per m 2 .
14. A fluidized bed granulator comprising a compartment with a floor with openings for a supply of a fluidization medium and a plurality of individual sprayers connected to a supply of a granulating liquid, wherein the sprayers are configured to spray the granulating liquid in one or more spraying zones next to one or more unsprayed zones of the fluidized bed granulator, wherein a distance between sprayers in a cluster is 0.1 to 0.4 meter.
15. A fluidized bed granulator comprising a compartment with a floor with an inlet for nuclei, a plurality of openings for a supply of a fluidization medium and a plurality of individual sprayers connected to a supply of a granulating liquid, the compartment defining a flow direction for nuclei from said inlet to an outlet, wherein the sprayers are configured to spray the granulating liquid in one or more spraying zones next to one or more unsprayed zones of the fluidized bed granulator, wherein the sprayers are arranged in clusters and wherein sprayers of each cluster are arranged in parallel lines extending in said flow direction.
16. A fluidized bed granulator comprising a compartment with a floor and with an inlet for nuclei, the floor having a plurality of openings for a supply of a fluidization medium and a plurality of individual sprayers connected to a supply of a granulating liquid wherein the sprayers are arranged in clusters parallel to each other, each cluster being elongated and comprising first sprayers at a first end of the cluster and second sprayers at a second end of the cluster with further sprayers spaced apart from each other and disposed between the first sprayers and the second sprayers, and wherein at least one unsprayed zone also extends between adjacent parallel clusters, the unsprayed zone defined by being free of sprayers wherein a transverse spacing, transverse to the elongation of the clusters, between two adjacent clusters exceeds intra-transverse spacing, transverse to elongation of the clusters, between the sprayers within each respective cluster.