Enclosed Flares for Biogas and CBG Plants
Enclosed biogas flares that safely burn surplus and off-spec gas at biogas and CBG plants.
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A safe route for surplus and off-spec biogas
CRA's enclosed biogas flares burn surplus, off-spec and emergency gas at biogas and CBG plants, with no visible flame and destruction efficiency above 98%.
Destruction efficiency
>98%
Methane operating range
20 to 80% CH₄
Flame visibility
Zero (enclosed chamber)
Operation
Fully automated
When does a biogas or CBG plant use its flare?
Digesters produce gas continuously, whether or not the plant can use it. When the engines, boilers, upgrading plant or compressors are down, or the gas is off specification, the surplus goes to the flare. The flare lights automatically, burns the gas inside its enclosure and shuts down once the main user is back.
How it works
The flare connects to the gas line after the gas holder, usually with a booster blower and a flame arrestor in its gas train.
A rising gas holder level or a trip of the main user calls the flare.
The flare lights its pilot and proves the flame.
Surplus gas burns inside the enclosure.
The flare follows the surplus flow as it changes.
When the main user is back, the flare shuts down automatically.
Key Benefits
Surplus and off-spec gas has a safe route whenever the main user is down.
The flare is designed to destroy more than 98% of the methane it burns.
The flare burns gas across a wide methane range.
Combustion stays inside the enclosure.
The flare starts, proves its flame and shuts down on its own.
Projects That Push Boundaries
Designed with continuous flame supervision and fail-safe shutdown for a public utility.
Designed for reliable, smokeless performance across variable gas quality and flow conditions.
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
Built to help you specify.
Sizing tools, decision guides, and technical references. Use them before, during, and after your evaluation.
Frequently Asked Questions
Why does a CBG plant need a flare?
When the upgrading plant or compressor trips, the digesters keep producing gas. The flare burns it safely so the plant does not vent methane.
How should the flare be sized?
The flare should be sized for the full gas production with the main gas user offline.
Can the flare burn off-spec gas?
Yes. CRA's biogas flares burn gas across methane contents from 20 to 80%.
What data does CRA need to size a biogas or CBG plant flare?
CRA needs the maximum and minimum gas flow, the methane content range, the supply pressure and the site conditions.
Does CRA supply flares for small plants?
Yes. CRA's semi-enclosed biogas flares come in standard models from 500 to 2,500 Nm³/h.