Spray drying is the process of turning liquids into solids in one step. It is commonly used in industry and has a variety of applications. Spray drying has applications in a range of diverse fields such as food, chemical, pharmaceutical and nanotechnology industries. There are several types of spray dryers. The Mini Spray Dryer is a laboratory grade machine that is used to spray dry and encapsulate pharmaceuticals, food products, catalysts, feeds, cells, fragrances, etc. Mini spray dryers are available from several manufacturers such as Buchi, Bergman Labora and Yamato Scientific.
BuchiMini Spray Dryer B-290 Source: www.buchi.com
A spray dryer produces dry powder from a liquid base by rapidly drying it by bringing droplets of the liquid with a hot gas. Spray drying is a speedy and time saving method of obtaining even the smallest amounts of substances in powder form. When compared to other methods such as freeze drying, spray drying offers higher throughput rate and shorter processing times. The thermal load is further reduced with organic solvents are used.
Thermally sensitive products such as certain foods and pharmaceutical formulations cannot be dried using conventional drying methods as it can result in the breakdown of the molecules. Spray drying, on the other hand, doesn’t result in fluctuations in the temperature applied and therefore doesn’t result in chemical breakdown. Spray drying also produces consistent particle sizes and is suitable for industrial grade products such as catalysts.
Mini spray dryers are suitable for producing powder at laboratory scale. They can be used for performing preliminary experiments or drying works at general laboratories. Due to smaller size, they cannot be used to process larger amounts of liquids. These devices are suited level applications. Since the mini spray dryer applies heat on fine samples instantly and doesn’t involve the application of heat to the dried powder, it can be used to dry substances that are broken down by heat. It also reduces the risk of oxidation and contamination of the end product.
Mini spray dryers have a number of applications. These include spray drying:
- Food and pharmaceutical products such as powdered milk, egg yolk, coffee, protein, hormones, antibiotics, fragrances, perfumes, essences, etc.
- Organic compounds such as waxes, cleaning agents, surface acting agents, resins, pigments, agricultural chemicals, etc.
- Inorganic chemicals such as ferrites, ceramics, printer toners, photosensitive materials, magnetic tape materials, industrial chemicals, etc.
Commercially available mini spray dryers also come with computerized operating panel displays that allow fine tuning of the parameters such as input and output temperatures and gas flow control for optimal operation. The instruments are versatile and can be used for particle coating, immobilization of liquids and solids in matrices, manufacture of microcapsules and modification of particle sizes. They also allow agglomeration of nanoparticles.
Solutions or suspensions containing the sample can be converted directly without the need for methods such as filtration or pulverization that are need for other methods of drying. Mini spray dryers can be also be connected to specialized units such as mini-bed attachment, solvent recovery unit, magnetic mixer unit, etc. to perform specialized functions.