Calculated automatically

Practice-oriented designing for rotary dryers


The following article examines a computation programme for the design of rotary dryers. A practicable method for the determination of the necessary dimensions is based on the volumetric drying rate, also referred to as the coefficient of evaporation. All data relevant for process-engineering purposes, such as throughputs, volumetric flows of gas, temperatures, heat demand and power requirement are determined. The computation programme is notable for the fact that practical experience is incorporated for the various process-engineering variants – with the user enjoying extremely large freedom of design, via the input of his or her own empirical data. This computation programme thus permits optimisation and adjustment to the given operational boundary conditions of the user/the designer of rotary dryers.

1 The practicable design of rotary dryers

The drying process occurring in a rotary dryer can be depicted theoretically by means of combination of the differential equations for heat transfer and mass transfer. These equations can be solved using, for example, similarity indices and the coefficients included in them for idealised cases, such as laminar flow, for example. This method is not appropriate for the practical design of rotary dryers, as a result not only of its restricted applicability, but also, and above all, as a result of the unknown similarity indices of the material to be dried...

Related articles:

Issue 01-02/2020 Allgaier Mozer TK-D rotary drum dryer/cooler system

Combined co-current drying and counter-current cooling in a rotary drum

Allgaier rotary drum dryers/coolers have a worldwide reputation as high-grade, powerful and efficient drying and cooling systems (Fig. 1). They are used, in particular, for processing free-flowing...

Issue 03/2010

Drum dryers or fluidized bed dryers

Criteria for selecting dryers for use in the minerals, chemicals and recycling industries

With its wide range of different drying systems, Allgaier can supply both fluidized bed and drum dryers of different types. On the basis of its experience of many reference applications, it can...

Issue 09/2010

Theory and practice

Drying in mineral processing

1 Basis principles of drying technology During the drying of solid, free-flowing materials, the key objective is to separate the materials from any moisture. The moisture is generally water, but can...

Issue 01-02/2023 Increased energy efficiency in high-temperature processes

Drying, calcination, reaction: higher product quality coupled with lower emissions

When it comes to the processing of minerals, the recycling of batteries or photovoltaic cells or the pyrolysis of biomass, high-temperature processes are integral to a number of industrial...

Issue 11/2019 Computation

The design of FAM special hammer mills for comminution and drying of bulk solids

1??? Introduction Over the last 40 years, the demand for fine- and ultrafine-grained powders has increased exponentially in many branches of industry worldwide, especially in the construction...