The Rotary Drum Dryer is easy to operate, versatile, and capable of handling high throughput despite variance in feed stock. The technology is simple in design and robustly built. These advantages lead to a widespread use of the technology all over the world.
Rotary drum dryers work with co-current heating where product and hot gas flow in parallel through the drum. Alternatively, they operate in counter-current mode, where hot gases circulate in opposite direction of the product direction. The ultimate configuration depends on the process requirements and how much the product may heat up. Powders, filter cakes, fibrous materials, chunks, and even sticky materials can all be processed. Heat carriers may be hot air, combustion gases, or even exhaust gases from other processes. Fuel can be almost anything and single fuel or dual fuel.
Wet product enters the drum either through a feeding device or just by gravity through a feed pipe. Guiding plates or baffles assist the wet product distributing itself homogeneously inside the slowly revolving drum. While revolving, specially designed lifting flights pick up the product and drop it down as a curtain. The hot air stream passes around the particles and exchanges its heat. On average, residence times are longer than many other technologies, and range for most applications between 30 to 60 minutes. The Rotary Drum Dryer is a technology very well suitable for unevenly shaped larger particles. And for products that come in a whole range of different particle sizes. Conversely, small particles are less suitable for this technology as they would be carried out with the hot gas stream.
Lifting flights and cruciforms inside the drum.
Cruciforms
Different to many other rotary drum dryers in the market, the Ingetecsa Rotary Drum Dryer uses cruciforms in the centre part of the dryer. Cruciforms are cross shape plates that sit almost along the entire length in the drum. All particles cross these ‘internal heat exchange plates’ while traveling to the opposite end of the drum. Cruciforms not only reduce fire danger, but also increase homogeneity of the heating up and drying phases. The result is a better quality end product than when produced in the simpler drums without this feature. There are many different shapes of cruciforms and Ingetecsa selects the best configuration for each application.
Our rotary drum dryers let themselves easily combine with our other machines, such as our fluidised bed dryer or fluidised bed cooler, or our flash cooler. Also, we offer different feeding and metering solutions. These are robust and designed to avoid bridging and blocking. Furthermore, a range of self-adapting sealing solutions are available to chose from depending on the product and the application. These highly developed special seals can do without a regular servicing as well as ensure absence of oxygen in the hot areas to minimise risk of fire.
Configurations
There are several configurations possible for all the different products. The Rotary Drum Dryer usually works with direct heat, where hot gases come in contact with the product.
For products that require indirect heating, we heat the shell on the exterior with hot gasses. Some rotary kilns use this concept, often for calcination processes. Substantial energy savings are possible by reusing the exhaust gases, for instance to pre-heat the product or to pre-dry. For more information on the calcination process and technology, please read here further.
Lastly, we design and manufacture 2-stage or 3-stage drums. Here, product enters through a centrally positioned inner drum and returns via the outer drum.
There are many, many configurations possible, based on different construction materials and fuels.
Contact us if you like to know how we can assist you selecting the best configuration for your application.
