Technologies

Spray Drying

Among the integrated technologies of Nol-Tec Europe systems, provided under the brand NTE Process, the Spray Drying is a very important process that allows to obtain high quality engineered powders for various industries (Food, Pharmaceutical, Ceramic, Environment, exc).

Nol-Tec Europe combines its own experience in powder Material Handling with the powder production thanks to the partnership with the Japanese company Ohkawara Kakokhi, worldwide leader in Spray Dryer production with patented technologies.

The Spray Drying technologies allow to atomize slurry and liquid compounds with different degree of viscosity, producing fine powders with precise particle sizes, thanks to patented atomizing nozzles. Furthermore, the obtained powders have a high degree of fluidity and solubility, thanks to the perfect distribution of the shape and of the particle size that is obtained by the atomizing process.

Nol-Tec Europe offers solutions with different approaches, from turnkey plants to retrofitting of existing systems, and also closed loop laboratory spray dryers.

Principles of Spray Drying
Spray & Dry Nol-Tec technology is the most dependable process for producing dry powders from any type of liquid solution or slurry feed. The feed is dispersed into a mist of fine droplets either by means of a rotary disc atomizer or a spray nozzle.
This spray mist is distributed into a cylindrical drying chamber along with a stream of hot gas and typically blown dry within a second split. After remaining in the chamber for a certain residence time - for further reduction of the residual moisture - the generated dry powders are separated from the gas flow either directly at the base point of the chamber or via downstream aero cyclones and bag filters.

No Heat Deterioration
On account of the comparably high drying speed and the short residence times, even
heat-sensitive materials such as pharmaceuticals or foodstuff and dairy may be dried without difficulty using spray dryers. If a rather slow rise in temperature of the spray mist droplets is required, also countercurrent flow systems are feasible.

Inflammable Solvents Manageable
For water-based feeds the drying media is filtered air in an open system. For inflammable or in any other way hazardous feeds, nitrogen in a closed loop dryer is used. This way, also all solvent is recovered and may be reused.

Consistency
In general, the particle size distribution of the acquired powders is sharp and consistent, due to easy control and reproducibility of the drying properties.
Spray dried powders exhibit high flowability, high solubility and dispersibility, allowing for facile transport, storage and subsequent processing.

High Purity & Easy Cleaning
Cleaning of all spray dryer components is straightforward and can be completed in just a short amount of time. Impurities and cross-contaminations can be avoided reliably. Automated WIP, CIP and SIP systems can be applied to spray dryers without difficulty.

Versatile Atomizers
Spray dryers can feature various atomizers for any type of feed or desired powder properties: rotary discs of different shapes and materials, single fluid pressure nozzles, twofluid nozzles, in-line intermixing nozzles, ultrasonic nebulizers and many more. Nol-Tec atomizer distributes the feed liquid to a mist of fine droplets with a high surface to volume ratio - essential for fast, accurate and gentle drying. Its design strongly influences the final product properties in terms of particle size & size distribution, shape, porosity, flowability and many more. The rotary disc and spray nozzle atomizers can easily cover all types of feeds at flow rates from less than one kilogram up to se-veral tons per hour and allow for dependable reproducibility and easy up-scaling. Feasible droplet sizes range from one single up to hundreds of microns in diameter.

Custom design
Laboratory use, medium-scale production and large industrial open and closed spray dryers, open and closed spray coolers, fluidized bed systems, exhaust gas coolers and treatment equipment, modifications of all basic model series on customer request.


Rotary Discs
This type of atomizer uses a vaned, serrated or perforated disc rotating at high speeds. The centrifugal energy provided by means of an electric motor or an air turbine drive translates into formation of a fine horizontal droplet spray.
With rotary disc atomizers also highly viscous and abrasive feeds or feeds with very high solid content may be processed while always maintaining easy control and a homogenoeus spray. Our rotary disc atomizers are available in capacities up to 12000 kg/h.

M-Disc
The curved teeth of the unique M-disc cause the feed liquid film to form a layer of uniform thickness over the entire height of the disc. This results in a remarkably sharp droplet size and therefore sharp particle size distribution, compared to other disc types. Narrow distribution of the atomized droplets will not only result in perfect flowability of the acquired powders, but also increase your overall yield.

Spray Nozzles
Nozzles convert pressure energy provided by the feed pump into kinetic energy resulting in single droplets. With exchangeable orifices nozzles can be adjusted to various operational conditions. Nozzles permit multiple atomizers in one single chamber and can therefore also cover largest capacities.

TwinJet-Nozzles
The newly developed RJ- and TJ-series TwinJet spray Nozzles cover the operating range of ultra-fine particles (single micrometer range) at both - low (RJ: 1 to 25 kg/h) and high (TJ: 25 kg/h to 1 t/h) feed rates in a single nozzle setup.
Their patented two-step atomizing technology, using pressurized air to break the surface tension of the liquid, extends the working range to particle diameters unrivaled by conventional spray nozzles or rotary disc atomizers.

Nol-Tec Europe has a Test Plant at its Research Centre in Pessano con Bornago (Italy) where spray drying test can also be performed for the customers, in order to optimize the engineering process both during quotation or job step and to test innovative products or processes together with the customer.

Our potential customer can research and design new products or verify how NTE Process Spray Dryer performance can be improved.

Furthermore, the test can prevent any critical issue that can occur during the plant start up, shortening the testing time.

A further test analysis provides relevant information for the design of the suitable engineering and the best settings for the performance control during the plant start up.

 

VISIT THE OHKAWARA'S WEB SITE: http://www.oc-sd.co.jp/english/

Spray Drying