A single-stage landfill gas blower can deliver about 160 mbar at 3,000 Nm³/h, and that is the highest pressure one stage achieves; a two-stage machine reaches more but at considerably higher cost. A standalone blower skid was offered to a landfill operator on that basis, with an optional knockout pot. A related earlier design boosted gas to a thermal oxidiser with a bypass so the downstream plant could run with the blower out of service.
The challenge: moving wet, corrosive gas
Landfill gas is saturated, 40 to 55% methane, with CO₂ and other gases, and can reach 60°C. The blower must be gas-tight, built to hazardous area standards and resistant to corrosion.
The approach: one skid, one drive
Design basis
| Parameter | Value | What it means |
|---|---|---|
| Flow | 3,000 Nm³/h | The design duty |
| Head | About 160 mbar g | The most a single stage delivers |
| Motor | About 30 kW | Variable speed |
| Ambient | 0 to 35°C | Outdoor under a weather shelter |
| Hazardous area | ATEX Zone 2, Cat 3G | Blower and motor both |
Scope
- A 304 stainless steel centrifugal blower, which needs no protective coating.
- A direct-drive Ex ec IE3 motor, with belt drive or cartridge bearing alternatives.
- A variable speed drive in a stainless steel IP56 panel, with an interlocked isolator and air conditioning.
- Inlet flame arrester, inlet and outlet butterfly valves, stainless bellows and anti-vibration mounts.
- Pressure gauges and a low-pressure switch to indicate blockage or failure; emergency stop.
- An optional stainless steel knockout pot with a polypropylene mesh demister (under 3 mbar clean pressure drop, 99% of particles over 6 microns removed) and a gauge that shows when it needs cleaning.
Why it works: variations on the duty
An earlier design for the same site type used about 2,750 Nm³/h at a roughly 150 mbar lift to feed an ammonia stripper’s thermal oxidiser. It used an explosion-proof motor, controlled the speed from the plant’s operator screen with settable duty points, normalised flow with a temperature probe, reused the existing flow meter and pressure instruments, and included a bypass so the plant could run without the blower. It also allowed for a chilled water dewatering circuit on the outlet. That scope included material and weld test certificates and a factory acceptance test.
The choice of head is the main design decision. For a higher-pressure duty, such as feeding engines, see sizing the gas booster. For UK guidance on gas management, see the Environment Agency’s landfill gas guidance.
What to consider for your own project
- Add up the pressure losses before choosing the head.
- Use a variable speed drive to follow gas flow.
- Fit a knockout pot unless one exists upstream.
- Provide a bypass where downstream plant must keep running.
- Check the exclusions: installation, power, foundations and dewatering.
FAQ
What limits blower pressure?
The number of stages. One stage reaches about 160 mbar in this duty.
Why stainless steel?
Landfill gas is corrosive, and 304 stainless needs no coating.
Is a knockout pot needed?
Yes unless liquid is removed upstream. The skid is not designed for liquid.
Can the blower be bypassed?
A bypass line with a manual valve was included in the earlier design.
Need a gas blower?
Tell us your flow and pressure and we will advise.