In comparison to the established twin-screw machines,the application of a planetary roller granulator for continuous operation of melt granulation is a promising alternative based on the unique process concept.An init...In comparison to the established twin-screw machines,the application of a planetary roller granulator for continuous operation of melt granulation is a promising alternative based on the unique process concept.An initial study focused on the material transport during processing as a key driver for the overall performance.Hereby,the impact of direct process parameters on the residence time distribution was the main objective.These investigations are complemented in this study by considering the free processing volume,which is defined by the number of planetary spindles applied within a module.The impact on the processing conditions is evaluated with respect to the process setting in terms of feed rate and rotation speed.The results highlight the potential of altering the underlying transport function in planetary roller melt granulation(PRMG)via the investigated direct process and equipment parameters.The impact of the feed rate is lower in comparison,while a higher rotation speed as well as a higher free processing volume promote material mixing.Moreover,a normalization of the determined residence time distribution(RTD)model data was feasible with respect to the process settings and the number of applied planetary spindles in the processing zone.This demonstrates the key role of the free processing volume in the fundamental mechanisms of material transport and mixing during PRMG.展开更多
This study focuses on the characterisation of strength, density, and size of granules produced in various scales of a high shear granulator. Calcium carbonate （Durca165） was used as the feed powder and aqueous polye...This study focuses on the characterisation of strength, density, and size of granules produced in various scales of a high shear granulator. Calcium carbonate （Durca165） was used as the feed powder and aqueous polyethylene glycol （PEG 4000） as the binder. The dried granules were analysed for their strength, density, size distribution, and wall make-up. Granules were produced in granulators with four scales, 1, 5, 50, and 250 L under three scale-up rules of constant tip speed, constant shear stress, and constant Froude number. The results show that regardless of equipment scale, increasing the impeller speed has a great effect on crushing strength and stress. The underlying cause is an increase in granule density due to more consolidation at higher impeller speeds. Wall make-up is significantly reduced to less than 5% as the scale is increased from 1 to 250 L. The results of this study corroborate our previous findings that the constant tip speed rule is the best criterion for scale-up of high shear granulators.展开更多
文摘In comparison to the established twin-screw machines,the application of a planetary roller granulator for continuous operation of melt granulation is a promising alternative based on the unique process concept.An initial study focused on the material transport during processing as a key driver for the overall performance.Hereby,the impact of direct process parameters on the residence time distribution was the main objective.These investigations are complemented in this study by considering the free processing volume,which is defined by the number of planetary spindles applied within a module.The impact on the processing conditions is evaluated with respect to the process setting in terms of feed rate and rotation speed.The results highlight the potential of altering the underlying transport function in planetary roller melt granulation(PRMG)via the investigated direct process and equipment parameters.The impact of the feed rate is lower in comparison,while a higher rotation speed as well as a higher free processing volume promote material mixing.Moreover,a normalization of the determined residence time distribution(RTD)model data was feasible with respect to the process settings and the number of applied planetary spindles in the processing zone.This demonstrates the key role of the free processing volume in the fundamental mechanisms of material transport and mixing during PRMG.
基金the EPSRC(Grant No.GR/S25029/01),Borax Europe Ltd.,Hosokawa Micron B.V.,Pfizer Global R&D,and Procter and Gamble for their financial support of this project
文摘This study focuses on the characterisation of strength, density, and size of granules produced in various scales of a high shear granulator. Calcium carbonate （Durca165） was used as the feed powder and aqueous polyethylene glycol （PEG 4000） as the binder. The dried granules were analysed for their strength, density, size distribution, and wall make-up. Granules were produced in granulators with four scales, 1, 5, 50, and 250 L under three scale-up rules of constant tip speed, constant shear stress, and constant Froude number. The results show that regardless of equipment scale, increasing the impeller speed has a great effect on crushing strength and stress. The underlying cause is an increase in granule density due to more consolidation at higher impeller speeds. Wall make-up is significantly reduced to less than 5% as the scale is increased from 1 to 250 L. The results of this study corroborate our previous findings that the constant tip speed rule is the best criterion for scale-up of high shear granulators.
