Innovation for drying sewage sludge: The benefits of the HUBER Disc Dryer RotaDry®

Extensive know-how, decades of experience and intensive studies and discussions: building on this foundation in sewage sludge treatment and recycling, HUBER launched the new HUBER Disc Dryer RotaDry® in 2020. The dryer is based on the functional principle of contact drying via steam-heated discs and, compared to other drying processes, impresses with its compact design as well as several innovative features, functionalities and decisive advantages for reliable state-of-the-art drying of sewage sludge.

Fully automatic control

• Online measurement of the dry residue at the inlet and (optionally) outlet of the dryer
• Improved processing of different sludge qualities
• Foresighted process operation and comprehensive operational control through early detection of fluctuating sludge quality
• Reduced operating effort and relief of the operating personnel
• Patent pending

Steam-heated discs: optimised design and fully automatically welded by robot

• Parallel steam-heated discs for drying the sludge
  • Uniform movement and distribution of a larger quantity of dried material
  • Continuously larger contact areas between sludge and disc
  • Optimised drying process
• Longer service life of the rotor discs due to reduced tolerable residual wall thickness of approx. 3.5 mm
• All welding points and seams are protected and thus less susceptible to wear and leakage
  • Significant reduction of the wear limit
  • Wear protection ring on the circumference of the disc to protect the weld seam underneath
  • Replacement of the wear protection ring is possible without extensive rotor disassembly to maximise the service life of the disc
• Central tube machined and drilled fully automatically in one operation
  • For stability reasons in structural steel, completely covered by the stainless steel discs
  • Greater wall thickness and smaller diameter to increase active disc areas
  • Higher water evaporation of the dryer with the same construction volume
  • Maintenance-free discharge of the steam condensate by rotation

Frequency converter-controlled direct drive of the rotor

• Variable speed via frequency converter to adapt to different sludge qualities and required capacities
• Higher efficiency of the dryer drive
• Significantly reduced noise emissions
• Significant reduction of wear
• Less maintenance-intensive components and thus relief for operating personnel
• Special seals between rotor and housing to prevent sludge leakage
• SEW gearbox with directly coupled motor for optimum lubrication of the high-speed bearing
• Automatic grease lubrication of the rotor and discharge screw bearings
• High-performance SKF bearings for long service life
• Chesterton packings for optimum safety and performance

Other specific product features

• Additional insulation of the dryer's head sides to increase working safety and significantly reduce heat loss
• Increased corrosion protection of the dryer through special covers with complete sealing of the flange connection between rotor and shaft end
• Components in contact with sludge made of stainless steel
• Automatic emergency water injection to avoid the sludge-specific glue phase
• Flow-optimised vapour dome to minimise the discharge of black water and deposits in the downstream pipelines
• Flexibility in the steam and condensate system to ensure an optimal overall solution for the plant
• HUBER steam control with minimum pressure drop due to optimised valve control during dryer heating and control operation
• Increased heating surface due to optional steam jacket
• Fully equipped with load cells, pressure transmitters, temperature transmitters, automatic control valves, inverter-controlled sludge discharge, HUBER measuring system for dry substance control for automatic operation

Certifications of production

• Pressure approval according to ASME Code, PED (Pressure Equipment Directive 2014/68/EU) or any other requirement in the country where the dryer is to be installed
• A machine manufactured in Europe in a manufacturing workshop certified according to DIN EN ISO 3834 / AD2000 HPO

Engineering, supply, installation, commissioning and HUBER Global Service

In addition to engineering, delivery, installation and commissioning of the disc dryer, HUBER also offers its proven Global Service. For further information, please contact us directly – we will be happy to help you at any time: sludge@huber.de.