Spray drying turns a liquid or slurry into a dry powder quickly using a hot gas. This is the suggested drying procedure for many heat-sensitive goods, such as those used in the food and pharmaceutical industries. Items dried with spray dryers may do so much faster than with conventional methods. They also simplify the process and increase profit margins by turning liquids into dried powders in a single step.
Process of Spray Drying
The most popular type of spray dryers is the single effect type. They make use of one drying air supply at the top of the chamber. Often, the air blows in the same direction as the liquid being sprayed, or in a co-current. Although it can flow slowly and produce more dust than other methods, it produces a fine powder. Multiple effect spray dryers, a more modern type of spray dryer, are used to address the dust and inadequate powder flow. Rather than drying the liquid in one phase, the drying process consists of two. The first phase is at the top, just like with a single effect dryer.
Application
In the manufacturing of pharmaceuticals, spray drying is used to uniformly distribute the active ingredients into a polymer matrix for administration as an amorphous solid. In this state, the medication’s active components are more energetic, which facilitates the drug’s distribution throughout the patient’s body. Moreover, chemicals, pharmacological substances, and antibiotics are produced via spray drying.
The food sector uses the spray drying encapsulation method to dehydrate products without the need for water, resulting in powder form. For example, numerous chemical components of a beverage are sprayed-dried to create quick drink mixtures. This technique can also be used to dewater food items like powdered milk, particularly skim. Thermal degradation of products can be reduced by using larger chambers for longer residence times and lower operating temperatures. This process is also used to create nutraceuticals, colorings, animal feed, spices, coffee, tea, eggs, flavorings, enzymes, vitamins, and sugar replacements like stevia.
Principle
By reducing the liquid to tiny droplets, a significant surface area is created for the mass and heat transmission. To turn the drops into solid particles, heated air is sprayed on them.
Construction
It consists of conical-base drying chambers. All components are composed of stainless steel. Both a hot air input at the bottom and a second intake for the spray disc atomizer are located at the top. Using nozzles, the drying chamber is connected to a cyclone separator for single- or dual-fluid atomization. The bottom of the separator is where the dry product is collected.
Working
Spray drying is a technique where liquid atomization is passed through a heated, gaseous drying medium and transformed into dry droplets. Before drying, atomization, spray air mixing, moisture evaporation, and the separation of the dry product from the exit air are the processes that happen in a spray drier. The first step in spray drying is atomization. The liquid feedstock is broken up into small droplets using a nozzle or rotary atomizer during the atomization process. Next, the suspension or solute is taken out of the solvent, first as a solid and then as a gas. Particle size and viscosity are two of the many desirable properties that are developed during this phase.
The droplets dried in atomizers and nozzles to create a powder that was convenient to package and transport. After drying, the droplets harden. Solids are typically gathered using cyclones or drums. The physicochemical properties of the feed along with the design and operation of the spray dryer determine the final product. Powder is frequently dried using hot air. The ultimate moisture content of the powder can be regulated by varying the hot air temperature. The powder can be recovered from the exhaust gas by circulating it again for a short while.
Uses
- Spray drying is used in the production of several medicinal products, such as enzymes, vitamins, yeast, vaccines, and plasma.
- A lot of industries, including non-pharmaceutical ones, use spray drying technology.
- Pharmaceutical gums, serums, spores, bacitracin, penicillin, streptomycin, tetracycline, sulfathiazole, yeast products, tannin products, and amino acids can all be dried using this drying agent in addition to other items.
- Microcapsules, gastro-resistant microspheres, and controlled-release systems can be made using dried liposomes, amorphous medications, and micro adhesive microspheres.
Depending on the fluid or slurries being treated, Kerone manufactures spray dryers ranging in complexity from simple to exceedingly difficult. Different design elements include the atomization, airstream pattern, air heating systems and techniques, separation and collection unit, and others. The main components of a spray dryer are an air heating system, a drying chamber, an atomization and dispersion system for introducing fluid into the chamber in tiny droplets, and a separation unit to collect the dried output.
Kerone has vast experience in designing and constructing spray drying machines, which are useful for several applications across multiple industries. Many of our clients have previously benefited from our assistance with their drying needs. Our excellent manufacturing processes and highly qualified technical team enable us to achieve precision and product quality.