DE4037866C2 - Continuous fluidized bed process for gentle drying of temperature-sensitive, moist products - Google Patents

Description

Continuous fluidized bed process for gentle drying of temperature sensitive wet products, the wet products in the fluidized fluidized material in a fluidized bed dryer (= moist, too drying product) and at temperatures below the boiling point temperature of the solvent can be dried, the control of the Pro product temperature in the fluidized bed through the mass flow and the tempera Turbine of the fluidizing gas and by the mass flow of the product, The vapors of the solvent are removed by the fluidizing gas and the dried end products are discharged from the fluidized bed.

Come to dry temperature-sensitive, moist products known processes, such as, for example, convective drying processes or Vacuum drying process used.

However, both methods have different disadvantages.

Furthermore, in the dissertation by T. Köblitz, University Erlangen-Nürnberg, year 1984, "The gentle drying of temperature sensitive granules in the radio frequency field ".

This involves gentle drying of temperature-sensitive pharmaceuticals products with a high-frequency field in a vibration flow diagram small dumping heights - ≦ 20 mm - shown.

The fluidized bed is generated mechanically and by the swirling product layer gas flow passed through serves exclusively for quick evacuation of the brothers.

However, this method has the following disadvantages:
the convective part of the drying process is missing,
the low gas flow only serves to remove the vapors,
Defined control of the product temperature in the fluidized bed is not possible
the fluidized bed is generated exclusively via vibration - mechanical energy input - and
only very small layer heights can be used, since otherwise there is a risk of the product to be dried overheating with the known disadvantages for the product quality.

It was therefore the task to develop a method that gentle drying of temperature-sensitive products in the vortex layer - while avoiding the disadvantages shown above - enables.

This object is achieved in connection with the features of the preamble of claim 1 in that the drying by dielectric heating of the moist products by means of a high frequency field and the temperature control over the fluidizing gas inlet temperature he follows.

An embodiment of the invention with the essential, inventive Features are shown in the drawing and will be described in more detail below described.

The drawing shows a fluidized bed dryer 1 with the fluidized fluidized material 2 (= moist product to be dried). The fluidizing gas 3 is heated via a heat exchanger 4 and distributed in the fluidized bed dryer via a distributor base 1 a. Through the filter 1 b fluidizing gas 5 and entrained vapors of the solvent leave the fluid bed dryer. Entry of the moist product to be dried into the fluidized bed dryer and removal of the dried product from the fluidized bed dryer take place via pipelines and known conveying elements 6 and 7 . The fluidized bed dryer is arranged within a device 8 for generating a high-frequency field. Using this high-frequency field, the moist product is dried according to the invention by dielectric heating.

The continuous driving style shown above differs in Ver equal to the discontinuous driving style only in that it is too dry product are not metered into the fluidized fluidized bed, but rather is placed in the fluidized bed dryer.

It goes without saying that in large-scale production plants not the entire fluid bed dryer is embedded in a high-frequency field is, but the dielectric heating of the moist products by means of commercially available magnetrons - arranged in the actual fluidized bed room - is achieved.

Claims (2)

1.Continuous fluidized bed process for the gentle drying of temperature-sensitive moist products, the moist products being metered into the fluidized fluidized bed in a fluidized bed dryer (= moist product to be dried) and dried at temperatures below the boiling point of the solvent, the control of the product temperature in the Fluidized bed occurs through the mass flow and the temperature of the fluidizing gas and through the mass flow of the product, the evaporation of the vapors of the solution is carried out by means of the fluidizing gas and the dried end products are discharged from the fluidized bed, characterized in that the drying is carried out by dielectric heating of the moist Products by means of a high-frequency field and the temperature control via the fluidizing gas inlet temperature. 2. Discontinuous fluidized bed process for gentle drying of temperature-sensitive moist products, whereby the moist Products in a fluid bed dryer (= moist, to be dried Product) submitted and at temperatures below the boiling point the solvent can be dried, the control of the product temperature temperature in the fluidized bed due to the mass flow and the temperature of the fluidizing gas and through the mass flow of the product, which The vapors of the solvent are removed by the fluidizing gas and the dried end products are discharged from the fluidized bed are characterized in that the drying by dielectric Heating the moist products using a high frequency field and the temperature is controlled via the fluidizing gas inlet temperature.