An existing landfill gas flare can be upgraded to automatic flame temperature control in about one day, using a PID controller, an actuator to drive the combustion air louvres, and a few relays and timers in the existing panel. This short post describes how that retrofit was scoped for a UK landfill flare, and how the scope was refined over three versions of the quotation.
The challenge: manual air control and a broken controller
The flare had no automatic control of its combustion air, and an existing temperature controller was broken. Without automatic control, flame temperature drifts as gas quality changes.
The approach
The parts needed were:
- A PID controller mounted inside the existing control panel.
- An actuator to drive the louvres.
- Relays and timers in the panel to manage the automated process, with additional wiring to the actuator.
Two people were expected to fit this on site within one day, including commissioning.
How the quotation evolved
- The first version included supplying and fitting the louvres.
- The second removed the louvres and was based on one engineer for one day.
- The third split the work into options: option A, automatic control (controller, relays, timers and actuator); option B, a replacement controller only; and option C, a reduction for ordering both.
The customer confirmed that only option A was needed, since it covered both the automatic control and the replacement of the broken controller.
Why it works
A PID controller compares the actual temperature with a set point and moves the louvres to close the gap. Retrofitting it is cheap compared with replacing the flare, and the flare then holds temperature in its working band as gas quality changes. It is a sensible upgrade for any older unit that must show consistent combustion.
What to consider for your own project
- Check the louvres can move freely before adding an actuator.
- Check panel space for the controller and relays.
- Ask for the scope as options so you can see what each part contributes.
- Look at the permit. See LFTGN05.
FAQ
How long does a retrofit take?
Around one day with two engineers in this example.
What does a PID controller do?
It adjusts the louvres continuously to keep the flame at its set temperature.
Upgrading an older flare?
Tell us the flare type and panel. Related: modulating valve failure.