Fuel Gas Heaters

[Deremis]

I would like to know what parameters to look at when chcking the efficiency of fuel gas heaters. For instance, is it possible to make any assumptions from the bridgewall or skin temperatures. The flowrate through the plant was increased for a while and I would like to know what parameters I can look at to determine the effect this had on the heaters.

Thanks!

 

[MariusChE]

Deremis

Define what you mean by "fuel gas heater efficiency". Do you mean: How much of the heat is taken up in the product stream? Or do you mean: How efficient is the combustion?

What types of furnaces are these? If they are coking/liquid cracker furnaces then one of the most important parameters is the dP over the passes.

Bridgewall temperatures are useful for checking NOx. Skin temperatures are good indicators of fouling in the tubes. If you had a rise in skin temps after the high-load run then you probably hurt the tubes.

Most operators hurt their furnaces during high-load runs because they do not adjust the air flow and they also do not adjust the fuelgas quality (if it can be done). The result is that the adiabatic flame temps can go over 2000F. The radiative heat goes up almost exponentially, through the roof, and if your process does not forgive you then it's time to get the pig out!

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