Fluidized Bed Dryer/Cooler

Heating of a fluidized bed dryer system

The heating of the air streams in a fluid bed dryer can be carried out with the help of different processes. Basically, the choice of heating system depends on the design options and the available heating media. Classically, the heating can be done directly via a gas/oil burner or with the help of an electric heating coil. Indirect hot gas generation via steam or thermal oil using heat exchangers is also possible. Thermal energy from other processes (waste heat utilization) can also be put to good use. Heat recovery from the process exhaust air or the use of high-temperature heat pumps is playing an increasingly important role in order to increase the efficiency of the overall system and reduce energy costs.

Combined fluidized bed drying and fluidized bed cooling

The combined processes of drying and cooling in one system can be particularly effective and profitable. Cooling of the dried product can be particularly important if further process steps follow after drying, such as screening, storage or bagging. In addition, the waste heat of the product, which is transported away with the exhaust gas flow during cooling, can be used efficiently to preheat the drying gas.

Energy efficiency of a fluid bed dryer

In Zeiten steigender Energiekosten und strikter Emissionsvorgaben ist es umso wichtiger, den energetisch effizienten Betrieb eines Wirbelschichttrocknersystems zu gewährleisten. Gerade die thermischen Prozesse gilt es zu optimieren, da hier die meiste Energie eingesetzt wird bzw. die höchste Emission erfolgt. Besonders große Potenziale zur Effizienzsteigerung bieten Wirbelschicht Trockner mit eingebauten Heizflächen oder die Integration von Wärmerückgewinnungssystemen, sowie die Verwendung von Hochtemperaturwärmepumpen.

In times of rising energy costs and strict emission requirements, it is all the more important to ensure the energy-efficient operation of a fluidized bed dryer system. The thermal processes in particular must be optimized, since this is where the most energy is used and the highest emissions occur. Fluidized-bed dryers with built-in heating surfaces or the integration of heat recovery systems, as well as the use of high-temperature heat pumps, offer particularly great potential for increasing efficiency.

Possibilities for energy recovery and efficiency increase

Energy recovery and the general increase in efficiency of thermal processes are a must today. Allgaier makes thermal drying processes Eco! With this in mind, the LeadingEcoSolutions program focuses on the core concerns of "Reduce CO2", "Reuse Energy" and "Reduce Costs". Based on many years of experience as a supplier of innovative drying systems, Allgaier offers advanced, energy-efficient solution concepts for industrial plants in this segment. In close cooperation with customers, all potential for energy savings is uncovered - always with a view to maximum benefit and a short payback period.

• Effective drying that is gentle on the product due to optimum flow around the particles.
   

• Individually adjustable inflow zones for drying and cooling to ensure an optimum fluidization condition.

• The vibration support enables even difficult-to-fluidize products with a wide particle size distribution or sticky characteristics to be dried effectively. In addition, the vibration support prevents cratering within the product layer.

• Compact designs possible with maximum performance.

• Wide range of applications: For example, for drying plastic granules, animal feed and sugar or expanding foam granules as well as heating urea and cooling cocoa or salts.

• Energy-efficient processes through a small-scale system tailored to the respective application area, optimized heat generation and heat recovery.

Limits of fluidized bed technology

The limits of fluid bed technology are indeed very broad. There is hardly a moisture product among bulk materials or granulates, powders or other granular, flowable materials that cannot be processed accordingly. Allgaier offers its customers drying systems that can be adapted to a wide variety of products. A specific system is available for all industries in which the processes in question play a role - from the processing industry to food-producing or pharmaceutical plants. By using equipment options, such as an agitator in the product feed area or back-mixing possibilities to influence the product properties of the dampening solution, the application limits of fluid bed technology can be pushed further.

What is a fluidized bed dryer?

A fluidized bed dryer is a system in which bulk materials or granulates, powders and granules, powders and other granular, free-flowing moisture products are kept in suspension by a hot gas stream by a hot gas stream and effectively dried in the process. Often, fluid bed drying is combined with a fluid bed cooling within the same apparatus.

How does a fluidized bed dryer work?

A wet product is fed into the fluid bed dryer, where it is efficiently dried and cooled by a drying/cooling zone specially designed to meet specific requirements. This drying technology can be designed for continuous operation or for batch productions (batch operation).

When are fluidized bed dryers used?

Fluidized bed dryers have a wide range of applications. Typical applications are the processing and drying of crystalline products, granulates and powders for the stone and earth, chemical, mining, recycling, pharmaceutical and food industries.

What temperatures does a fluid bed dryer operate at?

The process temperature depends individually on the respective moisture product. Depending on the respective fluid bed technology (static fluid bed dryer, free oscillator, two-mass oscillator), high supply air temperatures of up to 600°C can be realized.