Spray drying is a process that uses hot gas to quickly dry a liquid or slurry into a dry powder. Many thermally sensitive products, such as foods and pharmaceuticals, as well as those requiring extremely constant, tiny particle sizes, favor this type of drying. The heated drying medium is air; however, nitrogen is used instead of the liquid that is flammable, such as ethanol, or if the product is oxygen-sensitive. ALAQUA is a spray dryer supplier as well as other processing equipment suppliers like evaporators, crystallizers, heat exchangers, distillation equipment, and solvent recovery systems.
Spray dryer transforms liquid into solid by vaporizing the solvent in a hot stream, with a drum collecting the solid. To maximize heat transfer and the rate of water vaporization, one typically uses a nozzle to reduce the droplets to the smallest size possible. While, depending on the nozzle, droplet sizes can vary from 20 to 180 m. Two types of nozzles exist: single-fluid high-pressure nozzles and two-fluid nozzles, where one fluid dries, and the other compresses gas.
When compared to other drying technologies, spray dryers can dry a product quite quickly. They streamline the process, converting a solution to dried powder in one step, boosting profits.
In pharmaceuticals, spray drying disperses active ingredients evenly into a polymer matrix, producing Amorphous Solid Dispensation. Moreover, the state boosts drug energy, facilitating better dispersion in the patient’s body for improved effectiveness.
Principle of Spray Drying Method:
Spray drying, the favored method, atomizes liquid into droplets for direct contact with hot gas, yielding powder through evaporation and separation. And, a solution, an emulsion, or a suspension, as well as a molten liquid or a paste, may be used as the raw material liquid. So, you can use air, nitrogen, or superheated steam for drying.
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Applications of Spray Drying Method:
Spray drying excels in pharmaceutical and food industries, meeting GMP criteria and delivering superior results, making it highly favored. And, it works well for drying and granulating Chinese and Western medications and foods. Therefor, highly disintegrating granules with excellent fluidity and rapid solubility are suitable for direct use in tableting, capsule filling, and solid beverages.
The spray drying process is an active method employed in dye drying. So, it’s enables the dry dyeing of fine powder, super-fine powder, dust-free powder, and hollow granules.
We divide this procedure into three groups:
- Airflow Atomization, which uses compressed air or water vapor to atomize the material liquid;
- Pressure Atomization, which uses a high-pressure pump to force the material liquid out of the nozzle at a high rate, resulting in a mist;
- Rotary Atomization, where the liquid material is introduced to the atomizer’s high-speed spinning disc (7000–28000r / min), then swiftly flung out and atomized. Hence, Rotational atomization is preferred in the dyestuff business for its efficiency, speed, and high labor productivity. However, it necessitates a significant capital investment and substantial energy usage.
Spray drying is an example of material drying technology that has been implemented in a systematic way. Once the material atomizes in the drying chamber, the heated air quickly evaporates the moisture, producing the dried product. Hence, evaporation and crushing can be avoided with this strategy. Quick heat transfer, short water evaporation, and quick drying time are all advantages of spray drying. While, spray drying accelerates dissolution in formulations, ideal for heat-sensitive meds; it also produces microcapsules.
Advantages of spray dryer Method:
- Process of rapid drying
- Drying materials directly into powder are possible.
- It’s simple to tweak product quality criteria and vary drying conditions.
- Drying chamber maintains hygienic conditions, prevents dust in workshop, and enhances product purity with slight negative pressure.
- There are fewer operators and higher manufacturing efficiency.
- The production facility can apply several hundred tonnes of high-quality spray in an hour.
Disadvantages of Spray Drying Method:
- The complicated machinery spans a wide area and requires a substantial financial investment.
- A spray dryer and powder recovery system costs a lot of money.
- The heat consumption is significant and the thermal efficiency is low.