ANDRITZ Gouda paddle dryer

The ANDRITZ Gouda paddle dryer is a robust, energy-efficient solution for continuous, indirect drying of products.

Engineered for high thermal efficiency and uniform product quality, it is ideal for environmental, chemical and food industry applications. Its compact design and plug flow operation make it a preferred choice for demanding drying processes.

Advanced technology for indirect contact drying

The paddle dryer operates on a once-through principle, ensuring that each particle of product experiences a consistent residence time. Inside the omega-shaped trough, two counter-rotating shafts with wedge-shaped paddles provide optimal heat transfer. These paddles generate shear forces that prevent buildup of materials on the paddles (encrustation) and maintain high thermal conductivity. The dryer has precise temperature control, residence time, and uniform end product because it is a plug flow reactor.

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ANDRITZ Gouda paddle dryer

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ANDRITZ Gouda paddle dryer for sludge

Key features and benefits

Plug flow design of the paddle dryer ensures that the product is treated uniformly in the dryer, resulting in a product which meets the desired design moisture content and product quality.
Designed to operate in vacuum conditions for low-temperature operation, which is ideal for heat-sensitive materials such as food ingredients or polymers.
Compact dryer with low footprint bringing a large, heated surface in small volume. No additional air is introduced into the dryer and therefore the amount of gas is reduced to a minimum. This feature makes it an ideal dryer for problematic or chemical processes or residues.
Can be used for solvents recovery in low temperature, vacuum, applications.
High temperature execution (up to 300°C) for heat treatment processes, driving crystal water in mineral processing.
Plug flow design for consistent product quality.
Self-cleaning paddles prevent buildup and maintain heat transfer.
Vacuum drying for low-temperature, sensitive applications.
Compact footprint with high thermal efficiency.
Modular configuration with multiple heat zones.
Low emissions and odor control for environmental compliance.
Customizable feed/discharge systems for various material types.
Certified to ATEX, PED, ASME, NFPA, TÜV standards.

Versatile applications across industries

Designed to handle a wide range of materials, the ANDRITZ Gouda paddle dryer is used in:

Environmental applications: Municipal and industrial sludge, pulp and paper sludge, drilling mud, digested manure, biomass treatment, waste heat recovery, fertilizer production.
Minerals and Mining: Rare earth mineral processing, minerals, metal powders
Chemical processing: Polymers (PET, SAP, PA) fertilizers and salts
Food industry: Milk powder, starch, cocoa, flour, sugar, hazelnuts, infant food cereals.

Its adaptability makes it suitable for drying, heating, cooling, reacting, roasting, calcining, sterilizing, and solvent stripping.

Customizable process configuration

ANDRITZ offers modular configurations tailored to specific process needs. Options include:

Two heat zones for staged drying.
Vacuum models for low-temperature applications.
Gas-tight covers for safe solvent recovery.
Compliance with international standards: ATEX, NFPA, TÜV, PED, ASME.

The entire unit can be inclined to optimize product flow, and feed/discharge systems are customizable for various material consistencies.

Sludge drying plant featuring ANDRITZ Gouda paddle dryer

Technical specifications of the ANDRITZ Gouda paddle dryer

The dryer is designed for indirect contact drying, offering precise thermal control and high energy efficiency. Unlike convective drying systems, which rely on hot air to transfer heat and remove moisture, contact drying uses heated surfaces to directly transfer energy to the product. This method minimizes dust generation, reduces odor emissions, and allows for better control over product quality, especially important for sensitive or hazardous materials.

Core specifications include:

Drying surface area: Available from 2.2 m² to 300 m², depending on model size.
Paddle design: Hollow, wedge-shaped paddles mounted on dual counter-rotating shafts; ensures continuous self-cleaning and efficient heat exchange.
Trough geometry: Omega-shaped trough facilitates plug flow and prevents back-mixing.
Heating medium: Steam, thermal oil, or hot water; adaptable to process requirements.
Operating pressure: Up to 30 bar(g) for steam-heated models.
Temperature range: Up to 300°C depending on heating medium and product sensitivity.
Vacuum execution: Available for low-temperature drying of heat-sensitive materials.
Material of construction: Stainless steel (AISI 304, 316), Hastelloy, or other alloys based on product compatibility.
Compliance meets global standards such as ATEX, PED, ASME, NFPA, and TÜV standards.
Drive system: Heavy-duty gearboxes with variable speed control; optional frequency converters.
Instrumentation: Integrated sensors for temperature, pressure, and level monitoring.

Sustainability and environmental impact

Drying sludge with the ANDRITZ Gouda paddle dryer reduces volume by a factor of 4–5, reducing significantly disposal costs. In the process Class A biosolids are produced, suitable as fertilizer or biofuel. Heat recovery from the condenser (up to 80°C) enhances energy efficiency. The enclosed system minimizes odor and emissions, supporting environmentally responsible operations.

Paddle package to boost performance, cut downtime, and lower costs

A newly developed paddle package has been designed to significantly extend service life and reduce maintenance costs in high-wear applications:

Extended wear protection preventing unplanned downtime: Engineered for abrasive environments, the new paddle components are built to last up to 2 years in continuous operation.
Quickly replaceable wear-parts instead of time-consuming and costly weld-on repairs: Featuring a bi-metal wear plate and a fully cast paddle nose, the new design allows for easy and fast replacement, minimizing downtime.
Planned maintenance breaks and spare parts on stock are minimizing total cost of ownership: With a fast return on investment, this upgrade delivers long-term savings and improved machine availability.

Currently available for new machines, this paddle package sets a new standard in performance and maintenance efficiency for the ANDRITZ Gouda paddle dryer.