A high-temperature landfill gas flare earns trust through a test certificate, not a brochure claim. For a 500 m³/h ground flare designed for 1,200°C, an independent laboratory measured combustion chamber temperature on site and recorded an average of 1,215°C across a methane range of 25% to 50%. This post explains the design, the proof and the practical details a buyer should settle before ordering.

The challenge: a buyer who needed evidence

A distributor supplying a landfill in southern Europe needed a flare that would hold a high combustion temperature and keep working as gas quality changed. The end client’s engineers wanted documentary evidence, not assurances. Over several months they also raised questions about electrical supply, analysers, warranty and payment security.

The approach: an MC Range ground flare

The design

• Flow: 500 m³/h with a 5:1 turndown, giving a minimum flow of about 100 m³/h.
• Temperature: a design temperature of 1,200°C when methane is above 28%, falling as methane drops towards 20%.
• Residence time: at least 0.6 seconds.
• Thermal output: about 2.5 MW at 50% methane.
• Shroud: 7 m high, with an adjustable-height muffle to help retain heat. The chimney was specified hot-dip galvanised, with pins to hold 150 mm of ceramic blanket.
• Control: a PID controller moving a combustion air louvre, with a PLC sequencing ignition. Ignition is more than a spark. It involves the igniters, a UV flame sensor and a secondary air damper that is set mechanically at start-up and then returns to PID control.

The Environment Agency’s guidance on monitoring enclosed flares (LFTGN05) gives 1,000°C and 0.3 seconds as the indicative UK standard. A design at 1,200°C and 0.6 seconds sits comfortably above it.

The proof

The supplier’s flare type had been tested on site by a specialist landfill gas testing laboratory. The certificate states the equipment was inspected and tested against the contract requirements, and that it operated at an average of 1,215°C within a methane range of 25% to 50% by volume. The buyer asked for the original documentation and was sent it.

If you are buying a flare for any market, ask for this: who tested, where, at what methane range, and what the average and range of temperature were.

Why it works: the details that get settled in negotiation

Booster and power

The booster delivered a total head of about 300 mbar. Its 7.5 kW motor was limited to a maximum absorbed power of 90% of rating. At 415 V the full load current is 15 A, and the maximum starting current is 38 A in star configuration. The engineers also asked about protection, so the answers were written down:

• an adjustable overload on the star contactor, set 2 A above full load current;
• a 20 A motor-rated miniature circuit breaker on the contactor feed;
• individual breakers on transformers and power supplies, and a single breaker on the 110 V AC control system;
• a 63 A door-interlocked isolator at the incomer, with a recommended 63 A switched fuse isolator and a 300 mA earth leakage detector on the customer’s feed.

NOx

The base flare produces NOx at up to 200 mg/m³. Exhaust gas recycle and fuel staging can reduce that to a maximum of 100 mg/m³ and were offered as an extra. High-temperature flares trade lower trace-gas emissions against higher NOx, so the limit that matters most for your permit should drive the choice.

Analysers

Analysers were not in the original scope. When the buyer asked about a nitrogen analyser, the supplier advised that it would be costly, and that a methane, oxygen and carbon dioxide package lets the nominal nitrogen content be calculated by difference. It is a practical way to get the information without a specialist sensor.

Warranty, flow measurement and commissioning

• A two-year warranty covering defects in materials and workmanship.
• An orifice plate flow meter and flow totaliser, brought into the base scope during negotiation.
• Commissioning within one to two days.

What to consider for your own project

1. Ask for the test certificate early. It takes a long time to arrange if it does not already exist.
2. Define the methane range you need. A flare certified at 25–50% methane may not suit gas that falls below that.
3. Send electrical queries in one list. Motor current, protection and isolator ratings are all standard questions.
4. Decide on NOx limits before pricing. Retrofitting is harder than specifying it.
5. Settle payment security with an overseas buyer. This project used a confirmed letter of credit, and amendments to it slowed the delivery schedule. Allow time.

FAQ

What is a high-temperature landfill gas flare?

An enclosed ground flare that holds the combustion chamber at a controlled high temperature, here 1,200°C by design, to destroy trace gases and keep the flame out of sight.

How is flare temperature verified?

By on-site measurement from an independent laboratory, recorded in a certificate of test and conformity that states the methane range and average temperature.

Why does a high-temperature flare produce more NOx?

Nitrogen oxides form more readily at higher flame temperatures. Exhaust gas recycle and fuel staging can reduce them.

Can I get nitrogen content without a nitrogen analyser?

Nominally, yes. With methane, oxygen and carbon dioxide measured, the nitrogen content can be calculated by default.

Need a flare with documented performance?

Talk to our engineers about temperature, methane range and test evidence for your site.