Spray Dryer

A spray dryer is a system that removes moisture using controlled heat and airflow for uniform drying results.

It operates through a process of heat transfer and air circulation to evaporate moisture from materials efficiently.

It provides high efficiency, uniform drying, and low energy consumption.

Industries such as food, chemical, pharmaceutical, and textile rely heavily on these dryers.

Yes, Kerone designs systems tailored to specific process and material needs.

The design ensures quick cleaning and minimal servicing requirements.

Kerone’s systems are optimized for reduced power consumption and higher heat utilization.

Yes, they are available in lab, pilot, and industrial models to suit all capacities.

Dairy and food processing, pharmaceuticals, detergents, ceramics, agrochemicals, and specialty chemicals are the primary users of spray dryers. The reason is that spray drying converts a liquid feed into a dry powder in a single continuous operation, in seconds, while preserving heat-sensitive components. No other single drying technology achieves this combination. For products like infant formula, encapsulated flavours, and inhalation drug powders, the control over particle morphology, size, and moisture content that spray drying offers is unmatched. Competing technologies like drum drying or freeze drying either damage product quality or are economically prohibitive at large production volumes.

Outlet air temperature is the primary control parameter for residual moisture in the final powder. It is maintained by adjusting the feed flow rate rather than the inlet air temperature, because inlet temperature is typically set to a fixed value that balances drying rate and thermal sensitivity. When outlet temperature rises above setpoint, feed rate is increased. When it falls below setpoint, feed rate is reduced. Modern spray dryers use PID-controlled peristaltic or centrifugal feed pumps coupled to the outlet temperature measurement for closed-loop control. Kerone integrates this control into the PLC system with recipe storage, allowing repeatable moisture targets across production batches.

Scale-up from lab-scale to production spray dryers is not linear and requires careful engineering. The key scale-up parameter is the specific evaporation rate; kilograms of water evaporated per cubic metre of chamber volume per hour. However, droplet trajectory, residence time, and wall deposition behaviour change with chamber diameter and height. Kerone operates a pilot-scale spray dryer at its R&D centre where customers can run trials with actual feed material to generate scale-up data. Parameters like inlet temperature, feed rate, atomiser speed, and outlet temperature from the pilot trial are used in proprietary scale-up calculations to specify production chamber dimensions, airflow volumes, and heater capacity.

In a co-current spray dryer, hot inlet air and atomised feed enter from the same end and travel in the same direction. Droplets contact the hottest air first but are protected from high temperatures by evaporative cooling, making this configuration suitable for heat-sensitive materials. Counter-current designs introduce hot air from the bottom while feed is atomised from the top, resulting in longer particle residence time and lower outlet moisture, preferred for materials that need very low final moisture and can tolerate higher temperatures. Mixed-flow designs combine both principles. The large majority of food and pharmaceutical spray dryers worldwide use co-current flow because it is the gentlest to the product.

Yes. Spray dryers can be configured with integrated fluid bed chambers (spray-fluid bed or spray-fluidised bed agglomerators) at the base of the drying chamber. In this configuration, partially dried particles from the spray stage fall into a fluidised bed zone where they contact other particles and form agglomerates before final drying. This produces a porous, open-structure powder with superior instant dispersibility in water, the characteristic of 'instantised' products like coffee creamers, infant formula, and instant soup powders. Fines returned from the cyclone can be re-introduced into the agglomeration zone to improve yield and produce a more uniform granule structure.