Premix Technologies designs side-entry long shaft paddle agitators for biogas and CBG plants where high-viscosity slurry, fibrous feedstock and high total-solids substrates must be mixed without upsetting biological activity. The low-speed, high-torque design supports gentle circulation, floating-layer breakup and settled-solids suspension in primary digesters, secondary digesters and digestate storage tanks.
Introduction: Long Shaft Paddle Agitator for Biogas Plant
Premix Technologies designs side-entry long shaft paddle agitators for biogas and CBG plants where high-viscosity slurry, fibrous feedstock and high total-solids substrates must be mixed without upsetting biological activity. The low-speed, high-torque design supports gentle circulation, floating-layer breakup and settled-solids suspension in primary digesters, secondary digesters and digestate storage tanks.
Design Features
Slow speed, high torque operation: engineered for low-RPM mixing where high-solids substrates need strong movement with controlled shear.
Long shaft construction: shaft length, support arrangement and paddle spacing are customized for large tank diameters and deep reactor geometry.
Multi-paddle design: inclined paddles create bulk circulation, break floating layers and keep settled solids in motion.
External drive assembly: motor and gearbox remain outside the tank for easier access and maintenance.
Mechanical sealing and bearing support: sealing, external bearings and internal guide support are selected for gas-tight biogas service.
Energy-efficient operation: low speed reduces power demand while maintaining dependable digester circulation.
Biogas slurry, manure, fibrous feedstock and high-viscosity substrate
Tank Diameter
Typically 15 m to 30 m and project-specific larger tanks
Impeller
Long shaft paddle type with multiple inclined paddles
Speed Range
Low-speed operation, commonly 6 to 15 RPM depending on reactor duty
Motor Range
Application-specific selection, typically 11 kW to 22 kW or as required
Shaft Length
Customized, commonly 5 m to 11 m for large digesters
Material
SS, galvanized steel, coated steel or project-specific corrosion protection
Benefits
Floating-layer breakup, sediment control, better gas yield, low noise and easy external maintenance
CFD Assisted Agitator Engineering Review
Computational Fluid Dynamics (CFD) is used as an engineering support method to understand liquid circulation, velocity distribution, turbulence, vortex tendency and possible dead zones before finalizing agitator configuration. This helps our team match impeller type, RPM, shaft position, baffle arrangement and motor power with the actual process requirement.
For industrial agitators, CFD review is useful for blending, solid suspension, heat transfer, gas dispersion, slurry handling, fermentation and high-viscosity mixing duties. It gives customers a clearer view of how the mixer will perform inside the vessel, especially where tank geometry, viscosity, solids loading or batch quality is critical.
Engineering Points We Review
Flow pattern, circulation path and tank turnover
Dead zones near the wall, bottom dish and process nozzles
Impeller tip speed, shear level and velocity profile
Baffle requirement to reduce vortex and improve mixing
Power draw, torque and gearbox loading for reliable operation
Scale-up behavior from pilot trials to production vessels
Customer Benefits
Better agitator selection for the real process duty
Improved mixing uniformity and batch consistency
Reduced risk of sedimentation, floating layers and unmixed pockets
More confidence in motor, shaft, impeller and seal selection
Useful technical support for new tanks and retrofit applications
CFD flow visualization used for agitator selection, impeller performance review and mixing improvement.
Related Products
Agitator Impellers
Paddle, propeller, turbine, anchor, rushton turbine, gate, disperser, helical ribbon and hydrofoil impellers for industrial mixing duties.
Premix Technologies supported us with a reliable dosing system and quick technical response. The equipment quality and installation support were very professional.
Water Treatment Client
Google Review★★★★★
The agitator supplied by Premix is performing smoothly in continuous operation. Their team understood the process requirement and suggested the right configuration.
Chemical Process Customer
Google Review★★★★★
Good product finishing, timely communication and dependable service. The dosing pump package was delivered as committed and worked well after commissioning.
Industrial Utility Project
Google Review★★★★★
We appreciate their practical engineering approach and support after supply. Premix is a good partner for agitators, dosing pumps and chemical dosing systems.
