Rotary Cooler — Product Stabilisation After Drying
Granules leaving the dryer are hot, and hot granules cake in storage, damage bags and keep curing reactions running. The rotary cooler brings product temperature close to ambient using controlled counter-current air flow, protecting granule quality from the dryer discharge to the warehouse.
Why Cooling Is a Process Step, Not an Accessory
In fertilizer production, warm granules stored in bulk continue to exchange moisture and heat, which leads to caking — fused lumps that destroy product value. Cooling the granules to near-ambient temperature before storage or bagging interrupts this mechanism and keeps the product free-flowing.
The cooling drum works like a dryer in reverse: ambient or conditioned air flows counter-current to the hot granules, picking up their heat while flights shower the material through the air stream. Air volume, drum geometry and retention time are calculated from the required temperature drop and the granule properties.
Typical Applications
- Granular NPK and organomineral fertilizer after rotary drying
- Compost-based granules before bagging
- Mineral granules and processed sand products
- Any granular product where storage temperature drives caking risk
Technical Features
Counter-current air design
Maximum temperature difference along the drum for efficient heat removal.
Flight geometry
Cascading patterns that expose granules to air without degrading them mechanically.
Dust-controlled circuit
Cooler exhaust air routed to cyclone and filter, recovering fines to the process.
Mechanical package
Riding rings, rollers and drive identical in quality to our dryer line.
Data Required for Cooler Sizing
| Design input | Role in the calculation |
|---|---|
| Product and granule size | Air velocity limit to avoid carry-over |
| Inlet product temperature (°C) | Heat load to be removed |
| Target outlet temperature (°C) | Air volume and retention time |
| Capacity (t/h) | Drum volume and mechanical sizing |
| Ambient conditions at site | Cooling air design temperature |
Cooler dimensions are determined per project from the heat balance; site climate data improves accuracy.
Why Pro Makina
Manufactured in Turkey
Design and fabrication are carried out in our own facility in Eskişehir, Turkey, with full in-house engineering control.
Project-based engineering
Every machine is sized around your raw material, moisture content and capacity target — not sold from a fixed catalogue.
Export experience
We prepare international technical proposals, shipping documentation and commissioning support for overseas projects.
Single point of responsibility
Process design, fabrication, automation and commissioning are managed by one engineering team.
Frequently Asked Questions
Is a cooler always required after a dryer?
For bagged or bulk-stored granular fertilizer it almost always pays back through avoided caking. For products consumed immediately or insensitive to temperature it can be omitted — we assess this in the line design.
Can the cooler share the dust collection of the dryer?
Depending on air volumes and temperatures, cooler exhaust can be combined into a common filter or handled separately. Both variants are engineered case by case.
What temperature drop can be achieved?
Typically the product is brought to within a defined margin above ambient temperature; the exact figure depends on climate data, air volume and retention time and is stated in the project design.
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Share Your Project Details
Send us your raw material, capacity and process data. Our engineering team will review your requirements and prepare a project-specific technical proposal.
Rotary Cooler — Product Stabilisation After Drying
Final dimensions, capacity and drive power are determined per project, based on your raw material analysis, moisture content and process calculations.