Proses Anticaking Pupuk NPK [PDF]

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ASKOCOATTM Spray Curing Process Resins for Fertilizer Coatings, 2019



ASKOCOATTM – Resins for Fertilizer Coatings  ASK Chemicals offers 2K PU resin systems for the production of polymer coated controlled release fertilizers based on all kind of granules.  Part A contains a modified solvent-free phenolic resin formulation with natural oils.  Part B contains a modified isocyanate formulation including a bench life extender to inhibit the acceleration and to achieve a controllable reaction in the mixing equipment.  Amines accelerate this reaction; so far recommendation of gaseous DMIPA.



 ASK developed a new coating process using a liquid catalyst.  Advantages, coatings procedures and results will be presented on the next slides.



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Agenda  Equipment  General Information  Experimental Part



 Results  Summary



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Coater



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Dosing pumps



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Conductivity Equipment



Cold-Water test 29.07.2019



Hot-Water test Confidential



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Gas Curing Process (5 x 2wt% PU, coating procedure @ 70 °C) Experimental Part:



 2 kg fertilizer granules (NPK) are preheated to 70°C and filled into the coating drum  Prepare a mixture of 20 g Askocoat 420 and 20 g Askocoat 500 (2 wt% with respect to NPK fertilizer)  Slowly add the premix to the preheated fertilizer granules



 Add gaseous catalyst stream and wait until curing occurs (this will take several seconds)  Remove catalyst by flushing with air and transfer to an acid-scrubber  Repeat coating procedure to achieve the appropriate release properties (recommendation of 5 steps).



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Askocoat 420 + Askocoat 500 (standard, gas curing)



conductivity / mS cm-1



20



Increasing PU-layer thickness!



1 x 2wt% PU-coating (2wt%)



15



2 x 2wt% PU-coating (4wt%) 3 x 2wt% PU-coating (6wt%)



10



4 x 2wt% PU-coating (8wt%) 5 x 2wt% PU-coating (10wt%)



5



0



0



1



2



3



4



5



6



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9



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Why using the Spray Curing Process?  Gaseous catalyst, e.g. dimethyl-N-propylamine (DMIPA), needs a special handling due to high volatility (including hazardous materials transportation) Easy handling of catalyst desired  Gaseous catalyst needs a special nozzle-system in order to ensure a good distribution Easy dosing of catalyst desired  Gaseous catalyst emissions are caught with an acid scrubber No acid-scrubber required to remove emissions of amine in the case of liquid catalyst  Curing with gaseous catalyst needs ATEX equipment No ATEX equipment required for liquid catalyst with high flash point (fp)



Low-cost alternative while maintaining all safety standards!



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Alternatives to Gaseous Catalyst Gaseous catalyst DMIPA,



fp ~ -11°C, ATEX-equipment absolutely recommended! bp ~ 65 °C



Liquid catalyst Cat 804,



fp ~ 40°C: Easy handling, ATEX-equipment recommended bp ~ 134°C



Liquid catalyst Cat 806,



fp ~ 88°C: Easy handling, no ATEX-equipment necessary bp ~ 204 °C CH3



 Cat 804 and Cat 806 differ in chemical structur –R– HO



 Hydroxy-functionality –OH irreversibly reacts with isocyanate



R



N CH3



No emissions!



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Spray Curing Process (5 x 2wt% PU; coating procedure @ 70 °C) Experimental Part:



 2 Kg fertilizer granules (NPK) are preheated to 70°C and filled into the coating drum  1st step: Prepare a mixture of 20 g Askocoat 420 and 20 g Askocoat 500 (2 wt% with respect to NPK fertilizer)  Slowly add the premix to the preheated fertilizer granules



 Spray curing with 2 mL Cat806  2nd – 5th step: Prepare a mixture of 20 g Askocoat 420 and 20 g Askocoat 500 (2 wt% with respect to NPK fertilizer)  Slowly add the premix to the preheated fertilizer granules  Spray curing with 1 mL Cat806



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Askocoat 420 + Askocoat 500 (Spray Curing)



conductivity / mS cm-1



20



Increasing PU-layer thickness! Improved performance!



15



1 x 2wt% PU-coating (2wt%) 2 x 2wt% PU-coating (4wt%)



10



3 x 2wt% PU-coating (6wt%) 4 x 2wt% PU-coating (8wt%)



5



5 x 2wt% PU-coating (10wt%)



0 0



1



2



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Summary  The use of liquid curing agents with high flash points opens the path for a straightforward



coating process  Curing agents with high flash and boiling points allow easy handling and avoid the installation of ATEX equipment  Hydroxy-functionality of liquid curing agents results in an incorporation of the catalyst in the



PU-shell No emissions of amine, no acid scrubber  Spray curing process offers comparable nutrient-release characteristics



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Thanks!



© ASK Chemicals 2015