Spray Drying – How and Why It Works
Spray drying is a continuous direct heat transfer process used to produce free-flowing dry powder in the form of small relatively uniform particles. The liquid solution or slurry to be dried is pumped to an atomizer located at the top of the drying chamber. The atomizer is designed to disperse the liquid into fine uniform droplets which are rapidly dried to form individual particles when coming into direct contact with hot air (gas) in the drying chamber. By controlling the droplet size, hot air flow rate and/or drying chamber temperature, the resulting residence time allows droplets to dry before reaching the walls of the drying chamber and form a free-flowing powder. The conical drying chamber design allows gravity and air flow from the process to convey the product to cyclone or baghouse collection systems prior to packaging.
The desired final product moisture content and particle size of the powder can be altered by adjusting the liquid droplet size, hot air flow rate and/or drying chamber temperature.
Spray Drying – Valentine Chemicals
Valentine Chemicals operates three on-site spray dryers to assist customers with all phases of product development, scale-up and commercialization. Each multipurpose individual drying system utilizes a Bowen spray dryer equipped with a 304 stainless steel conical atomizer wheel configuration.
Our 30 Inch Pilot Dryer is primarily used to validate viability of spray drying, produce samples for product qualification, quickly compare the performance of modified liquid formulations and establish preliminary operating parameters for production scale-up.
30″ Pilot Dryer
Our 7 Foot Commercial Dryer is routinely used for intermediate production scale-up and production of small commercial campaigns.
7′ Commercial Dryer
Our 28 Foot Commercial Dryer is primarily used for production of large commercial campaigns.
28′ Commercial Dryer
Valentine Chemicals’ integrated spray drying systems have processed aqueous solutions/slurries ranging from 5% to 65% solids at water evaporation rates ranging from 1 to 3,000 lbs./hr. By focusing on our versatility, flexibility, experience, and responsiveness, we are able to deliver a wide range of spray drying solutions to accommodate almost any customer challenge.
If spray drying is not a viable cost-effective option for your particular product, Valentine Chemicals has the ability to evaluate both Drum Drying and Paddle Drying concurrently for alternate solutions.
Spray Drying vs. Drum Drying – What’s the Difference?
Determining the best method of drying unique aqueous solutions, slurries and sludges can be a difficult task given the range of chemistries and applications requiring products in dry form. Understanding that there are a number of special techniques that can be used to allow liquids to be dried using various methods, some general guidelines will aid in selecting the most effective drying method.
Spray Drying is more suitable for low to moderate Viscosity materials that can be effectively atomized to produce fine liquid droplets. High Viscosity materials that do not properly atomize can often accumulate on the drying chamber wall as a mud-ring and fail to produce flowable dry powder.
Drum Drying is more suitable for moderate to high Viscosity materials that can effectively adhere to the drum surface as a thin layer or film. Low Viscosity materials that do not adequately adhere to the drum surface can often leak in the gap between the two drums and fail to produce powder or flakes.
Spray Drying is more suitable for producing powder with a smaller more uniform particle size which in turn creates a product with a consistent bulk density. In general, particle size is limited by the maximize liquid droplet size that can be generated by the atomizer during production.
Drum Drying is more suitable for producing powder or flakes with a larger less uniform particle size and a wider particle distribution. The particle size and particle distribution are also a function of the hammer mill and screening process used to produce the final product before packaging.
Spray Drying – Applications
Spray drying is an efficient chemical manufacturing process that uses a liquid feedstock to produce free-flowing dry powders. At Valentine Chemicals, spray drying is integral to our complete manufacturing solutions for an array of market applications and customized products, including:
O & G
- Friction Reducers
- Fluid Loss Additives
- Crop Application Enhancers
- Skin Care Additives
- Feed Enhancers