Good work Brian , i would have bet my last penny that there would be nothing left of that pipe after 1 hours run but Tom beat me too it !
If i were you i would just carry on and run that as is so you can at least see what will happen and in the mean time start work on a flute style nozzle for speed , cheapness and in keeping with simple ,once your nozzle has melted away just cap off that pipe and drill a new hole and insert a flute nozzle and a water drip and away you go .
I love simple so try that before paying out money for copper pipe or even the silicon carbide that i use that’s still in my gasifier since Aug 2018 .
Here is a link to all types of nozzles we have used
Dave