Pots and pans.....A CO connection?

[doug112959]

Correct me if I am wrong. When burning fuel, the nitrogen and carbon mixed with oxygen and burns. The nitrogen burns quicker than the carbon. The carbon has to make it to the outside of the flame where as it gets its oxygen and burns off. When the carbon does not completely burn off the result is CO... Incomplete combustion. I have had 2 maintenance mechanics where I work tell me that certain types of pots or pans will trigger CO detectors. Anyone ever heard this before? I am ALMOST sure that CO is ALWAYS from incomplete combustion. (Maybe heated pots produce something other than CO that set off detectors)

[glewis29]

http://en.wikipedia.org/wiki/Combustion
http://en.wikipedia.org/wiki/Carbon_monoxide

From what I'm reading there, most of the Nitrogen that is present comes from the air and most of that isn't burnt (consumed). The majority of what is burnt is Methane (Ethane, Propane and Butane to a lesser degree). Some of the nitrogen can be oxidized, but it's not a major factor. Any incomplete combustion appears to be due to an insufficient amount of oxygen to fully use up the fuel (Hydrocarbon) present (resulting in Soot and CO instead of CO2 & Water).

From the article, in complete combustion CO appears to be a result of a side reaction of the oxidation of N2 in the air (air being 78% N2) in addition to being a result of incomplete combustion. Thus it seems that while incomplete combustion will raise the CO level, it is not the only source of CO

On a side note is something I learned while getting my science teaching credential. A complete combustion flame burns cleaner and thus has a blue flame. Any time the combustion isn't complete it gets contaminated with soot and shifts toward a white, yellow, orange, red color depending on temperature (hot to cold)...fun stuff
http://en.wikipedia.org/wiki/Flame

How that relates to pots and pans... no clue.

[davidr]

As the water in the pan is heated up the CO level production will drop off.

If it is being heated internally in a gas oven the CO is coming from the flue collar on the oven if it is unvented.

[craig1]

I have had 2 maintenance mechanics where I work tell me that certain types of pots or pans will trigger CO detectors. Anyone ever heard this before? I am ALMOST sure that CO is ALWAYS from incomplete combustion. (Maybe heated pots produce something other than CO that set off detectors)

theoretically copper and aluminum pots and pans could produce more CO than steel ones. the reason is that they conduct more heat away from the flame, resulting in incomplete combustion. if they are filled with something cold the problem would be worse. i still doubt it would be enough CO to trigger a detector.

[mark beiser]

On a side note is something I learned while getting my science teaching credential. A complete combustion flame burns cleaner and thus has a blue flame. Any time the combustion isn't complete it gets contaminated with soot and shifts toward a white, yellow, orange, red color depending on temperature (hot to cold)...fun stuff
http://en.wikipedia.org/wiki/Flame

You can still have high levels of CO production from a nice pretty blue flame.

[glewis29]

http://www.cdc.gov/nasd/docs/d000701...6/d000766.html

"FLAME INDICATES EFFICIENCY

The flames on most burners that use a gaseous fuel such as natural gas or liquified petroleum gas should burn steadily with a clear, blue flame, except for special designs such as fireplace logs and torches. A wavering, yellow flame on a normal gas burner indicates that the burner is out of adjustment or the air inlet is restricted. As a result, the burner may be producing excessive amounts of CO"

Under what circumstances would a blue flame be producing high levels of CO?

[mark beiser]

http://www.cdc.gov/nasd/docs/d000701...6/d000766.html

"FLAME INDICATES EFFICIENCY

The flames on most burners that use a gaseous fuel such as natural gas or liquified petroleum gas should burn steadily with a clear, blue flame, except for special designs such as fireplace logs and torches. A wavering, yellow flame on a normal gas burner indicates that the burner is out of adjustment or the air inlet is restricted. As a result, the burner may be producing excessive amounts of CO"

Under what circumstances would a blue flame be producing high levels of CO?

From the same article:
* Improper fuel-air mixture.
* Insufficient ventilation of combustion gases.
* Insufficient fresh air intake.

I have worked on many furnaces that had a nice blue flame off the burners, but were producing >400 ppm of CO in the flue gasses.
I have even run into some burners on stoves that were making >200 ppm of CO, but the flame was just as nice and blue as the burner next to it that was making <10 ppm CO.

This is why nobody should be allowed to work on combustion appliances without a combustion analyzer, or at the very least a CO meter that can do flue gas sampling.
IMO, it literally should be illegal.

[glewis29]

Good to know, thanks