I haven't seen a gas fired rod oven.
Water vapor is a byproduct of combustion with gas burners, the very thing we want to avoid in low hydrogen electrodes. Unburned gas could be a source of hydrogen as well. I really don't know if these would be absorbed into an electrode coating at temps above 250 deg F but I have a feeling it could be a problem.
I would think that in order to avoid contamination an oven would need to be indirectly fired and vented. That sounds complicated and bulky compared to electric ovens.
Not being in an area where natural gas is readily available yet I have to ask, would you be saving that much money by using gas?
If you do find gas rod ovens, I'd be interested in the info for comparisons.
Just some thoughts
CHGuilford
As far back as June, 1973, I authored a short article on Power magazine explaining how I built an electrode drying oven using LPG (liquefid petroleum gas) as a fuel.
The problem arose because we were constructing a natural gas compressing station in the Patagonian desert of the south of Argentina, 70 miles away from civilization. Power for the jobsite was supplied by a 45 kW diesel generator set and I wasn't willing to have it running all night just to keep the electrodes oven turned on.
So, we designed and built an electrode oven heated by the combustion of LPG. Special precautions were taken to prevent the electrodes from getting into contact with the combustion gases, which, as Chester Guilford points out quite correctly, contain water vapor.
If interested, let me know your address and I'll send you a copy of the article.
Giovanni S. Crisi
Sao Paulo - Brazil