Selecting a biogas burner differs from selecting a natural gas burner; you cannot rely solely on boiler capacity. The most critical step is to first determine the biogas composition, calorific value, supply pressure, and flow rate before selecting the specific burner model.

I. Determine 6 Key Parameters First

1. Biogas composition CH₄%, CO₂%, H₂S% ⭐⭐⭐⭐⭐

2. Biogas calorific value kWh/Nm³ or MJ/Nm³ ⭐⭐⭐⭐⭐

3. Biogas flow rate Nm³/h ⭐⭐⭐⭐⭐

4. Biogas pressure mbar / kPa ⭐⭐⭐⭐⭐

5. Boiler/equipment capacity kW ⭐⭐⭐⭐⭐

6. Operating mode Pure biogas / Biogas + Natural gas

II. Consider the CH₄ Content First

Biogas is typically not pure methane; it contains significant amounts of CO₂, resulting in a calorific value that is notably lower than that of natural gas.

For example, the reference conditions specified by Riello for its standard biogas solutions are:

CH₄ ≥ 65%

CO₂ ≤ 35%

H₂S < 0.1%

Relative humidity < 60%

Dew point < -10℃

PCI ≈ 6.46 kWh/Nm³

If the CH₄ content is below 65% (e.g., 50%–55%), Riello explicitly states that a specific application assessment is required, as gas composition affects burner sizing and the selection of accessories.

Therefore:

CH₄ around 65%–70% → Relatively easy to select a standard biogas burner.

CH₄ 50%–55% → Not recommended to simply match the model based on natural gas standards; the manufacturer needs to perform a recalculation.

III. Determine Burner Capacity Based on Boiler Capacity

For example, if you have:

A 4-ton steam boiler

You generally need to determine the boiler's actual fuel input capacity first, rather than simply asking, "What kW rating matches a 4-ton boiler?"

Assuming the final calculation indicates the burner requires:

Approximately 3,000 kW

Then the burner's operating range must cover:

Minimum load < 3,000 kW < Maximum load

Additionally, it is best to avoid running the burner near its maximum capacity for extended periods.