From foods to minerals, a variety of industries use industrial coolers to cool bulk solids for subsequent handling, storage, or transportation. When selecting industrial cooling equipment, the choice often comes down to a rotary cooler or a fluid bed cooler.
In general, rotary coolers have been used in settings requiring a more robust solution, such as in the mining industry, while fluid bed coolers have been reserved for lighter-duty applications such as pharmaceuticals and food stuffs. In some cases, the selection of one type of cooler over the other may simply be one of preference.
Despite some overlap between the two devices and comparable capital costs, both cooler types offer distinct advantages and disadvantages that may offer better performance in a given setting. The many factors to consider between rotary coolers and fluid bed coolers are summarized here.
Rotary Cooler Basics
A rotary cooler is a robust and long-lasting industrial cooling solution. The main advantage this cooler type has to offer is its heavy-duty construction; the robustness of a rotary drum accepts a broad range of feedstock at a high capacity, making it the workhorse of the bulk solids processing industry for both drying and cooling procedures.
Rotary coolers use a counter-current air-flow design, along with ambient or chilled air, to more efficiently cool material compared to cross flow fluid bed coolers. Additionally, flights lift and cascade material as it tumbles through the drum, enhancing the cooling process.
Typical rotary cooler process applications include:
- Fertilizers
- Industrial Waste
- Limestone
- Minerals and Ore (e.g. copper)
- Municipal Waste
Fluid Bed Coolers
A fluid bed cooler is a modular cooling solution. It suspends material in a flow of air or gas, causing material to behave as a fluid. The resulting fluidization provides gentle material handling capabilities. Additionally, the entire surface area of the material is exposed while it is suspended in a fluidized state, increasing cooling efficiency in certain applications.
Typical process applications include:
- Chemicals
- Food Processing (e.g. sugar)
- Pharmaceuticals
- Minerals (e.g. Sand)
Considerations When Choosing an Industrial Cooler
Though cooling is not required in all material processing applications, when it is required, it is essential for cooling equipment to be the most effective and efficient cooling solution possible. When choosing between a rotary cooler and a fluid bed cooler, factors such as the material to be cooled, spatial footprint, operational considerations, and energy consumption will help to determine which cooler is most appropriate.
Material Considerations
As mentioned, rotary coolers are generally better suited for more heavy-duty materials. This is because it requires significant energy to fluidize large or heavy materials, making fluid bed coolers less practical in such settings.
Since most material processing issues are resolved prior to the cooling process, there are typically fewer concerns to resolve in the cooling process. Consequently, the equipment is often designed with process efficiency in mind, with each unit providing advantages to a wide range of materials. However, if feedstock uniformity is a concern (moisture content, particle size distribution, etc.), rotary coolers will provide a better fit, as they are much more tolerant of variation in feedstock.
When the material to be cooled must not suffer any degradation, the fluid bed cooler may be a better option. As a result of the cascading action imparted by the rotary cooler, some, albeit little degradation and attrition can occur.
Spatial Footprint
A rotary cooler is typically larger than a standard fluid bed cooler. Some facilities are simply not big enough to accommodate the larger footprint of a rotary cooler, making a fluid bed cooler the obvious choice. The fluid bed cooler’s modularity also leaves open the opportunity to add on more units in the future when operational growth is a likelihood.
Operational Considerations
Though perhaps less of a concern than when compared with dryers, fluid bed coolers are less tolerant of operational instabilities and subsequently, require more supervision. Fluid bed coolers require as much uniformity in process conditions as possible and can be highly problematic in situations where this is not the case.
Energy Consumption
Because a typical rotary cooler is larger than a fluid bed cooler, it is assumed that a fluid bed cooler is more efficient. Surprisingly, this is not true.
Because fluid bed coolers work by fluidizing material, a high magnitude of air is required. Furthermore, because it takes a certain amount of energy to fluidize a given material, energy costs are not reduced when running at lower capacities. Additionally, as mentioned, it may not be practical to use fluid bed coolers for high volume, heavy materials, as this will also increase energy costs.
Rotary coolers generally require less energy to cool material, and energy consumption is reduced when running at a lower capacity.
Maintenance & Lifespan
When properly maintained, rotary coolers and fluid bed coolers have a comparable life span. Their maintenance requirements are also comparable.
The chart below summarizes some of the most important considerations to examine when choosing between a rotary and fluid bed cooler.
Rotary |
Fluid Bed | |
|---|---|---|
| Energy Consumption | Requires less energy | Requires more energy |
| Thermal Efficiency | Comparable | |
| Capital Costs | Comparable | |
| Spatial Footprint | Large footprint | Smaller footprint
Modular design |
| Maintenance & Lifespan | Comparable | |
| Feedstock Variance | Insensitive to variance | Highly sensitive to variance |
| Industry | Minerals
Fertilizers Raw Materials | Pharmaceuticals
Specialty Chemicals Foodstuffs |
| Material Considerations | Some attrition
Some degradation due to dropping action | Less attrition
Little material degradation |
| Operational Considerations | Easily automated
Requires less skilled operator Operational consistency less of a concern | Requires a watchful eye
Requires highly consistent operational considerations |
Conclusion
While the choice between a rotary cooler and a fluid bed cooler may seem complex, ultimately, it comes down to material characteristics, spatial requirements, and operational considerations.
FEECO provides custom rotary coolers engineered and manufactured around the unique requirements and material characteristics of a project. Our extensive experience around hundreds of materials allows us to provide the most effective cooling solution possible. For more information on our industrial cooling solutions, contact us today!