Investing in an industrial dryer is a major process decision. The equipment needs to achieve the required moisture reduction and throughput while also handling the specific characteristics of the product. But these requirements cannot always be confirmed from equipment specifications alone.
A product that dries successfully in a laboratory or existing process does not automatically mean that the same drying approach will perform as expected at industrial scale. Drying behaviour can change with product characteristics, operating conditions and scale, which is why dryer scale-up needs to account for factors such as final moisture, product quality, throughput and process reliability.
This is where pilot testing becomes valuable. A well-designed pilot trial can provide practical information about how a product behaves under controlled drying conditions and help establish the process parameters needed for a larger system. Before committing to a full-scale industrial dryer, pilot testing can turn assumptions about the process into actual data.
An industrial dryer can be specified for a particular capacity, temperature range, or moisture-removal requirement, but these figures do not necessarily tell you how a specific product will behave inside the dryer. Two products with similar moisture content, for example, can respond differently to the same drying conditions because of differences in particle size, structure, composition, and moisture-binding characteristics.
This is why selecting a dryer based only on nominal capacity or equipment specifications can leave important process questions unanswered.
A pilot trial allows those questions to be tested before moving to full-scale equipment. Instead of asking only “Can this dryer handle the required capacity?”, the evaluation can examine:
• How quickly does the product release moisture?
• What drying conditions are required to reach the target moisture?
• Does the product undergo physical or quality changes during drying?
• How does residence time affect the final product?
• Does the proposed drying method remain suitable as throughput increases?
The distinction is important: equipment specifications describe what the dryer is designed to do, while pilot testing provides evidence of how the product and drying process actually behave. Scale-up studies specifically emphasize maintaining moisture targets, product quality, throughput, and process reliability when moving from smaller-scale testing to industrial production.
For this reason, pilot testing is not simply a preliminary demonstration of machinery. It is a way to generate process information that can influence the design and sizing of the eventual industrial drying system.
A pilot drying trial provides something that a datasheet cannot: actual process data for the product being dried.
The objective is not simply to see whether the product becomes dry. A useful trial helps establish how the material responds to the proposed drying method and which operating conditions produce the required result.
Depending on the product and dryer technology being evaluated, a pilot trial can help determine:
For example, GEA’s drying test facilities use product testing and process data to evaluate process viability, equipment configuration, and scale-up before a high-value capital investment. Their testing approach also considers product characteristics such as solids content, viscosity, and particle size distribution.
The value of the trial therefore lies in reducing unknowns before the industrial dryer is designed or purchased. Instead of relying entirely on assumptions about how a product should behave, the engineering team can work from observed drying performance.
A pilot trial should do more than confirm that the product can be dried. It should help identify the operating window in which the desired moisture level and product characteristics can be achieved consistently.
The exact variables depend on the product and dryer technology, but several are particularly important during pilot evaluation.
The condition of the material entering the dryer can significantly influence drying behaviour. Initial moisture content, particle size, physical form, and product composition should be recorded so that the trial results can be interpreted correctly.
Temperature affects the rate of moisture removal, but increasing temperature is not automatically better. The trial can help establish a suitable temperature range while observing the product’s response.
Air movement influences heat and mass transfer within the dryer. Testing different airflow conditions can help determine how effectively moisture is removed from the product without creating undesirable drying conditions.
The product needs sufficient time under the selected drying conditions to reach its target moisture. Pilot testing can help establish the relationship between residence time and final moisture rather than relying solely on theoretical estimates.
The trial should evaluate more than moisture reduction. The final product should be checked against the characteristics that matter commercially, such as appearance, texture, particle condition, or other product-specific requirements.
These variables are interconnected. Changing one can affect the others, which is why pilot testing is useful for understanding the actual drying window rather than evaluating each parameter in isolation. Scale-up research also highlights the importance of using small-scale experiments to establish conditions that can be translated into the required commercial performance.
The result is a more realistic basis for moving from a pilot system to an industrial dryer: not just knowing that the product can be dried, but knowing under what conditions it can be dried successfully.
The most useful outcome of pilot testing is not simply a set of successful drying conditions. The results can feed directly into decisions about the full-scale dryer.
Pilot data can help engineers determine whether the proposed drying technology is suitable, what process conditions need to be maintained, and what changes may be required when moving to commercial production.
For example, the trial may reveal that the product requires a longer residence time than initially expected, different drying stages are needed to manage moisture removal more effectively, or even the airflow needs to be distributed differently to achieve uniform drying.
This is particularly important during scale-up because the objective is not simply to make a larger version of the pilot dryer. Scale-up needs to maintain the required drying performance while accommodating higher throughput and the physical differences that come with commercial operation. Research on industrial dryer scale-up identifies factors such as final moisture, product quality, throughput, safety, and reliability as key considerations when transferring a process to a larger system.
In practical terms, the pilot trial creates a connection between product behaviour and equipment design. The information gathered can then be used to make more informed decisions about dryer capacity, configuration, operating conditions, and overall process integration before committing to the final installation.
A successful pilot trial should evaluate the complete drying outcome, not just whether moisture is removed.
The product coming out of the pilot dryer should be compared against the specifications expected from the eventual industrial process. This makes it easier to identify problems early, while changes to the process are still relatively straightforward.
Key areas to evaluate include:
Check whether the process consistently reaches the required final moisture level. It is also useful to observe how moisture changes throughout the drying cycle rather than looking only at the final value.
Examine the characteristics that are important for the finished product. Depending on the material, this could include colour, texture, particle integrity, appearance, or other quality specifications.
A trial should establish whether the product dries consistently. Uneven drying can indicate that the selected process conditions or equipment configuration need further adjustment.
Pilot results should provide a basis for understanding how the process could perform when scaled to the required production capacity. Scale-up studies use experimental data to connect smaller-scale drying behaviour with commercial throughput requirements.
One successful run is useful, but repeatability is more valuable. Running trials under comparable conditions can show whether the process produces consistent results or whether performance varies significantly.
The dried material should also be assessed after leaving the dryer. Its condition may affect conveying, cooling, storage, packaging or subsequent processing.
The goal is therefore to leave the pilot stage with evidence that the proposed drying approach can deliver the required product, under defined operating conditions, with a clear path toward industrial scale-up.
Pilot testing can be useful for many drying applications, but it becomes especially valuable when there is significant uncertainty about how the product will behave during drying or when the cost of getting the full-scale design wrong is high.
It is particularly worth considering when:
Scale-up literature identifies the transfer from smaller-scale testing to industrial operation as a significant engineering challenge, particularly when the objective is to maintain product quality and drying performance at higher throughput.
In these situations, the question is not simply whether pilot testing adds another step to the project. It is whether gathering process data before the final equipment decision can reduce the uncertainty surrounding that decision.
The end of a pilot trial should not simply be a statement that “the product dried successfully.” The more useful outcome is a set of practical findings that can support the engineering and investment decision for the full-scale system.
A well-planned trial should ideally establish:
A defined drying process
The trial should identify the conditions under which the product reaches the required final moisture and quality specifications.
Relevant process data
Results such as drying time, moisture reduction, and product response provide a basis for engineering calculations and scale-up.
A clear understanding of product behaviour
The trial should reveal how the material responds to changes in drying conditions and whether any product-specific limitations need to be considered.
A basis for equipment selection and sizing
Pilot results can help determine whether the proposed technology and configuration are appropriate for the intended commercial application.
Identified scale-up considerations
Any changes required when moving from pilot operation to industrial production should be documented rather than left as assumptions.
Most importantly, the trial should leave both the processor and equipment supplier with more certainty about the process than they had before testing. Industrial dryer scale-up is ultimately about translating experimental results into reliable commercial performance, while maintaining the required product characteristics and production objectives.
That makes pilot testing more than a demonstration run. It becomes a technical foundation for the industrial dryer investment.
Pilot testing involves drying a representative quantity of the product on a smaller-scale system to study its drying behaviour and establish suitable process conditions before designing or purchasing the full-scale industrial dryer.
Pilot testing can provide practical data on moisture removal, drying time, product quality, and operating conditions. This helps reduce uncertainty when selecting, sizing, and configuring the industrial drying system.
Depending on the product and drying technology, trials may evaluate factors such as initial and final moisture, temperature, airflow, residence time, drying rate, product quality, and process repeatability.
Pilot testing cannot guarantee identical performance at commercial scale, but properly designed trials can provide valuable data for scale-up and help establish the conditions and equipment requirements needed for industrial operation.
It is particularly useful when the product is new, sensitive to drying conditions, difficult to dry, being produced at a significantly larger scale, or when there is limited process data available for selecting the industrial drying technology.
Pilot testing can provide valuable process data before committing to an industrial dryer. By understanding product behaviour, drying conditions, moisture requirements, and scale-up considerations, processors can make more informed equipment decisions.
At Global Dryers, we develop customised industrial drying solutions based on the product, process requirements, and desired production capacity. Our approach focuses on understanding the application before determining the appropriate drying system.
If you are planning a new drying line or evaluating a drying technology, talk to our team about your product and process requirements.
By T&I Global
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