Rotary Drum Dryers / Coolers
Reduced energy consumption and heat recovery with Combined Drying and Cooling
Combined Drum Dryers/Coolers from Allgaier are available in single-shell, double-shell and triple-shell designs. All three designs are combined systems in which drying and cooling take place in a single unit. Therefore, only one drive and one bearing are required in each case. Combined Drum Dryers/Coolers are offered in three types: TK, TK+ and TK-D. While the TK type is cooled by means of ambient air cooling, the TK+ uses evaporative cooling. The TK-D type is a further development. The TK-D complements the previous systems by offering the possibility of cooling to particularly low solid temperatures as well as efficient heat recovery and the resulting energy savings. The systems are particularly suitable for the processing of thermally and mechanically relatively insensitive, free-flowing bulk materials such as gravel, quartz and natural sands as well as limestone crushed sand.
Good to know
Functionality
In the Dying/Cooling Drum TK, cooling takes place by means of ambient air.
In the TK+ model, cooling is achieved by defined controlled admixing of moist material to the dry material within the two-pass drum (evaporative cooling). This process guarantees very energy-saving drying with simultaneous cooling.
With the single-flight TK-D, there are no points of contact between the cooling dry material and the hot inner drum in the inlet area of the dryer. This allows particularly low temperatures of the dried solids up to close to the ambient temperature or the temperature of the cooling air used. By means of a two-part design of the central area for separate extraction of the exhaust air streams from the drying zone and from the cooling zone, separate removal and dedusting of the two exhaust air streams is possible. While the moisture-laden dryer exhaust air is discharged into the atmosphere with dust removed, the warm but dry and dedusted cooler exhaust air can be returned to the process as preheated drying air. This results in heat recovery from the dried, warm solids. This results in an increase in efficiency and savings in necessary energy of up to 20%. In particular, the possible countercurrent flow of drying air and solids flow is suitable for particularly efficient high-temperature treatment and calcination of the solids with directly subsequent cooling.
Benefits
High performance: Very insensitive to fluctuations in material moisture, material grain size and feed rate.
High efficiency: Highest thermal efficiency due to very high hot gas temperatures and very high internal temperature difference.
Robust design: Very robust design for maximum service life with minimum maintenance costs.
Maximum flexibility: Easy to combine with a wide variety of heating systems and different fuels.
Type TK-D:
High performance: Cooling of the dried solids to particularly low temperatures to close the ambient temperature/temperature of the cooling air used.
High efficiency High energy efficiency through heat recovery in the drying process and evaporative cooling in the cooling process.
Multiple usage areas: Can be used for countercurrent calcination with subsequent cooling.
