5 replies to this topic

[pasquale]

Hi guys

Can anyone explain me what are the risk in a fired heater (fired with gas) when the pilot gas has an high- high pressure or a low-low inlet pressure , or when the fuel gas has a low low or an high high inlet pressure

Best regards

[gvdlans]

Well, basically the PSHH and PSLL are there to prevent loosing the flame. When a (pilot) burner has been lit and fuel gas pressure remains within the required pressure range (as per burner curve), you can safely assume that there will indeed be a flame. The PSHH/PSLL combined with flame detection (e.g. thermocouple for pilot flame and UV detection for main burners) ensure that there is a flame.

When you loose the flame and heater is not tripped, an explosive atmosphere can build-up in the heater box. If this is subsequently ignited this results in an explosion damaging the heater (and maybe hurting people).

[pasquale]

Thanks for the reply basically I knew that there is the possibility of loss of flame but I don't understand why it happens.

So, you can explain me ?

Moreover what are the burner curve ?

Thanks

Best regards

[gvdlans]

Burner curve of a particular burner is a curve showing amount of heat released vs. burner fuel pressure. It should be provided by the heater supplier (who should obtain it from the burner supplier).

If fuel pressure is too high the air/fuel mixture at the burner would become too rich (flame is "blown off"), while if fuel pressure is too low the air/fuel mixture would become too low. Both cases result in loss of flame.

[pasquale]

Thanks gvdlans
Basically if i have a high fuel gas pressure at the burner the gas flowrate is too high and i have a air/gas mixture less than the correct molar or weight ratio.

on the contrary for fuel gas low pressure.

It's correct?

Thanks

Best regard

[gvdlans]

Correct, and the heater/burner vendor can tell you in what pressure range the burner can operate safely.