Friday, November 27, 2015

Why is 'flame impingement' bad for the catalyst?



Simply put...direct flame contact is death to the catalyst.

A catalyst burns the byproducts in the smoke. The gases such as CO, HC, and O2 ignite with each other in a chemical reaction in the presence of the catalyst (while passing through the honeycomb configuration).

Direct flame inhibits this reaction by changing the chemical make-up of the catalyst breaking down the substrate or ceramic.

Today's modern wood burning stoves are designed so that flame impingement is unlikely. However, it is not impossible. A strong fast draft can pull the flames into the catalyst. A hot fire with all the primary air controls wide open or perhaps the firebox door or ash pan door ajar are other ways the catalyst might receive flame impingement.

1 comment:

E.K. Fults said...

I'm placing this comment here, in hopes that it might benefit some owners of the Dutchwest Federal 2462 (extra large) woodstove, who have experienced back puffing and steelcat combustor failures. After replacing two steelcats prematurely, I can attest that the factory supplied steel combustor deforms after a relatively short period of use, and worsens with time. It severely inhibits draft flow, so much so as to cause back puffing and poor combustor performance. The Firecat ceramic completely cured mine. This problem isn't as noticeable with the smaller Federals, due to the firebox volume. The Firecat ceramic also provides and much more consistent and longer lasting temperature profile than the factory steel combustor. Hopes this helps someone else. I'm a ceramic convert. Nothing else will ever burn my smoke again. Thanks Firecat.