Dear Gregg 8
As S/C ratio increases carbon deposition reduces. But higher S/C ratio needs more fuel at same tube outlet temperature and same H2 production. In terms of operating cost S/C ratio should be increased after executing various solution like removing thermal cracking before and inside...
I want to ask about material of tray and thermosyphon type heat exchanger in bottom. 99.999% oxygen is likely to combust with aluminium metal. NASA has experienced that and lost lots of space pilots by implosion with oxygen and cloths made of aluminium.
In addition 99.999% oxygen means 1 ppm...