Anaerobic digesters for biogas and compressed biogas (CBG) need the substrate distributed through the tank. Without mixing, fibrous material floats into a scum layer and grit settles on the floor, both taking up active volume and leaving dead zones.
Side entry mixers suit the large, low, round digesters common in CBG plants. They need no penetration of the gas-holding roof or membrane, and the drive stays outside. FMT digester mixers are heavy duty, with a gear or belt drive, a single mechanical seal, SS 304 or SS 316 wetted parts, and FLP motors where the gas zone requires them.
Typical applications
- Anaerobic digesters
- Slurry and substrate (feed) tanks
- Press mud, dung, food-waste and agri-residue digesters
Mixing objectives
- Distribute substrate through the digester
- Fewer dead zones and less solids accumulation
- Help manage scum, where the system is designed for it
FMT configuration for CBG & Biogas
| Drive | Gear or single-stage belt |
|---|---|
| Mechanical seal | Single mechanical seal |
| Motor | FLP or NFLP* |
| Wetted parts | SS 304 / SS 316 |
| Non-wetted parts | MS |
| Motor ratings | 2.2 to 37 kW |
| Mixer shaft speed | 280 or 450 rpm |
| Impeller | Hydrofoil or propeller |
* A flameproof (FLP) motor is supplied where the site's hazardous-area classification requires it. A non-flameproof motor is offered only where the area allows it.
Every unit is made to order for your tank. See the full side entry mixer range and specifications.
What we look at when sizing
- Feedstock and total solids (TS %)
- Fibre length and slurry rheology
- Gas zone classification and temperature
- Digester construction (steel or concrete) and nozzle position
- Corrosion and seal arrangement
- Continuous or timed operation