Biogas Systems for Dairies
Biogas handling systems that clean, dry, boost and flare the biogas from dairy effluent digesters for use in boilers and engines.
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Dairy biogas cleaned and delivered to the boilers
CRA supplies the gas side of dairy biogas plants: hydrogen sulphide scrubbing, moisture removal, boosting, metering, flaring and gas trains for boilers and engines.
Gas use
Boilers and engines
H₂S removal
Scrubber and carbon
Surplus gas
Enclosed flare
Scope
Gas handling
What does a biogas system do at a dairy?
Dairy effluent is rich in fats, proteins and sugars that break down in an anaerobic digester to form biogas. The biogas system cleans and dries that gas and raises its pressure so the plant can burn it.
How it works
Gas the plant cannot use goes to a flare, so the digester can keep running whatever the steam demand.
Biogas leaves the digester at low pressure.
A scrubber takes out the hydrogen sulphide.
Chilling and knock-out remove the moisture.
A blower raises the pressure for the burners.
The flare burns any gas the plant cannot use.
Key Benefits
Clean biogas replaces part of the fuel used for steam and hot water.
Scrubbing protects boilers, engines and pipework from corrosion.
Moisture removal stops condensate building up in lines and burners.
Blowers raise the gas to the pressure the burners need.
An enclosed flare burns gas that the plant cannot use.
The CRA Edge
CRA has more than 30 years of experience in gas handling and flare engineering.
Design, R&D and manufacturing are carried out under one roof.
ISO 9001 certified through TÜV NORD, with designs aligned with ASME, API and CE.
Designs are customised to the process needs and the regulations that apply at site.
Applications
Frequently Asked Questions
How can a dairy use its biogas?
Most dairies burn it in their steam boilers or hot water generators. Some generate power in gas engines.
Does dairy biogas need H₂S removal?
Yes. Hydrogen sulphide corrodes boilers, engines and pipework, so CRA removes it in a scrubber, with carbon polishing below 5 ppm where the gas user needs it.
Why does the system include a flare?
The digester keeps producing gas when the boilers are down or need less. The flare burns the surplus safely.
What data does CRA need to design a dairy biogas system?
CRA needs the biogas flow and how it varies, the gas analysis, the boilers or engines to be fed and the site conditions.
Can an existing boiler burn biogas?
Often it can, with a biogas or dual-fuel burner. CRA reviews the boiler and supplies the burner and gas train to suit.