Paddelrührwerke für Biogasanlagen
Effizienz, Homogenität und Zukunftssicherheit
Unsere Paddelrührwerke für Biogasanlagen
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Paddle agitators for biogas plants
Paddle agitators are now regarded as the modern, energy-efficient solution for biogas plants – particularly when processing demanding or fibre-rich substrates such as maize silage, manure and grass silage. They set the standard for mixing quality, reduce operating costs and maximise biogas yield.
An overview of the advantages of paddle agitators
- Optimal, homogeneous mixing: No risk of floating or sinking layers; maximum biological stability.
- High gas yield: Efficient distribution of microbes and faster substrate conversion thanks to uniform agitation.
- Energy efficiency: Reduced electricity consumption thanks to highly optimised paddle geometry – often requiring only around two-thirds of the energy used by propeller or submersible motor agitators.
- Low-maintenance and durable: Externally mounted, easily accessible drive unit and wear-free plain bearings – no need to enter the tank.
- Trouble-free operation even with difficult substrates: Substrates containing 15 % dry matter or more, as well as fibre-rich materials, can be processed without any problems.
- Flexibility in installation: Can be retrofitted; suitable for both concrete and steel tanks.
- Safety: Optional ATEX version available for potentially explosive atmospheres.
Comparison table: Paddle agitator vs. shaft-driven, submersible motor agitator & central agitator
| Feature | Paddle agitator (e.g. Varibull) | Shaft-driven agitator | Submersible motor agitator | Central agitator |
|---|---|---|---|---|
| Mixing | Very homogeneous, prevents stratification | Homogeneity is often insufficient; stratification is possible | Often strong locally, but poor mixing over a large area | Prone to ‘dead zones’, particularly with large diameters |
| Suitability for fibrous substrates | Excellent, particularly for high dry matter content and fibre content | Risk of rapid overload and winding | Rapid blockage with fibrous media | Sub-optimal flow with high viscosity and solids |
| Energy efficiency | Low power consumption thanks to optimal paddle geometry | Higher energy consumption, particularly with viscous substrates | Very high power consumption during prolonged operation | Varying; high drive power is often required |
| Maintenance & Service | Easy to access from the outside, low-maintenance, long service life | More complex maintenance, usually requiring access to the hopper | Regular maintenance inside the tank, close to the motor, wear parts | Sometimes complex: maintenance usually required inside the tank |
| Flexibility in installation | Can be retrofitted, variable installation position | Usually cannot be retrofitted | Good adjustment options, but limited mixing effect | Fixed central position, little scope for adjustment |
| Operational stability | High reliability even at high dry matter content | Problematic with higher dry matter (DM) and solids content | Performance losses with viscous substrates | Sensitive to fluctuating fill levels |
| Service life | Very high, wear-resistant bearings | Wear parts, frequent replacement | High wear, short service life | Sometimes long service life, but high maintenance requirements |
| Capital expenditure | Medium, very economical to run | Moderate, but higher running costs | Initially inexpensive, with additional costs due to maintenance | Often expensive in relation to benefits and maintenance |
Varibull Paddle Agitator – The Original for Your Biogas Plant
The Varibull paddle agitator offers innovation and safety from a single source:
- Large, angled mixing paddles ensure rapid, uniform and energy-efficient mixing.
- Durable construction, maintenance-free seals and simple external maintenance for maximum operational reliability.
- Maximum gas yield through optimal mixing.
- Low power consumption and robust enough for any tank size.
- Suitable for all substrates, including fibre-rich media and high dry matter (DM) contents.
Paddle agitators in biogas plants - Benefits and applications - Frequently asked questions (FAQ)
A paddle agitator ensures uniform mixing of the process fluids and helps to homogenise the suspension in biogas plants. This optimises microbial activity and increases biogas production. The effective flow patterns and the appropriate paddle geometry make the fermentation process more efficient, leading to a higher methane yield.
A paddle agitator is particularly well suited to energy-efficient mixing in biogas plants. Thanks to its robust agitator blades and the correct rotational speed, it requires less power to mix large quantities of substrate evenly. This reduces operating costs and improves the energy efficiency of the biogas plant.
Yes, paddle agitators are specifically designed for processing fibre-rich substrates such as grass, maize silage or manure. They prevent blockages and ensure uniform mixing, which optimises gas and methane production. The paddle geometry is designed to function effectively even at high viscosities.
Thanks to its effective mixing technology, the paddle agitator ensures that substrates are mixed quickly and evenly. This reduces mixing times, which optimises energy consumption and makes gas production more efficient.
A paddle agitator can operate reliably even when liquid levels fluctuate in biogas plants, as it distributes the substrate evenly provided it is installed at the correct height within the tank.
Thanks to its robust drive system and maintenance-free plain bearings, the paddle agitator requires very little maintenance. It has a long service life and is characterised by low maintenance costs, which improves the economic efficiency of the biogas plant.
Yes, paddle agitators can be easily retrofitted into existing biogas plants. They are compatible with various types of digesters, whether steel or concrete tanks. This enables cost-effective and rapid retrofitting.
The paddle agitator ensures uniform mixing and prevents foaming, which improves gas quality in the biogas plant. It maximises methane production and ensures higher gas output.
What are the main differences between a propeller mixer and a paddle mixer in biogas plants?
Rod agitators operate with a vertical stirring motion. However, they offer a lower mixing efficiency with fibrous substrates or high viscosities. Paddle agitators, with their horizontal stirring motion, ensure uniform mixing of the substrates, even when fill levels fluctuate, making them ideal for biogas production.
Paddle agitators are more energy-efficient due to their agitation technology and the effective geometry of the paddles. They require less power and are ideally suited to biogas plants for reducing energy consumption. Rod agitators have a lower circulation capacity and require more energy; they are therefore less energy-efficient.
Paddle agitators are significantly better suited to fibrous substrates such as maize silage or manure. They prevent blockages and ensure uniform mixing, whereas propeller agitators often encounter problems with high viscosities and fibrous materials.
Thanks to their robust drive technology and maintenance-free plain bearings, paddle agitators require less maintenance. They have a long service life and incur lower maintenance costs. Rod agitators, on the other hand, often require regular maintenance as they are more prone to mechanical faults.
Paddle agitators offer a high degree of flexibility and are suitable for various types of substrate. They operate effectively even at high liquid levels and can cope with fluctuating substrate conditions. Rod agitators are less flexible and are only suitable for specific applications, particularly with homogeneous liquids.
The paddle agitator ensures uniform mixing of the process fluids, which optimises microbial activity and thus methane production. Better homogenisation of the suspension leads to stable gas production, whilst propeller agitators are less efficient when dealing with heterogeneous substrates.
Paddle agitators require less maintenance due to their robust construction and low susceptibility to wear. Shaft agitators are often more expensive to maintain, as they require more spare parts and frequently cause problems with difficult substrates.
Paddle agitators are better suited to large fermenters as they have a significantly higher circulation capacity. This agitation technique ensures even distribution and higher gas production, which is often not the case with rod agitators.
Paddle agitators are more cost-effective in the long term, as they consume less energy and require less maintenance. Shaft agitators have higher operating and maintenance costs, particularly when used in challenging applications.
The Varibull mixer is based on the same tried-and-tested technology as the Paddelgigant, which we originally developed ourselves. Whilst other manufacturers have relocated their production abroad, we continue to manufacture the Varibull mixer in Germany. This enables us to ensure consistently high quality and durable workmanship. We have also further refined the design in a number of areas to enable even more efficient mixing and a longer service life.
