I dont do 10 gallon batches but, 1 BTU raises 1 lb of water 1o f. Burners are usually rated BTU per hour. Raise 10 gallons, say 85 lbs-ish of wort from say 68 to 212 in an hour is about (85x(212-68))= 12240 BTU, if all the heat from the burner transfers to the wort. It wont, some will go to air, plus heat loss from the liquid through the pan, so add in a percentage. 20% would get to about 15000 BTU. I would guess this would get u to boiling in an hour. More would be faster.
I use a 30,000 camp chef for 5 gallons and it will boil within half hour running at about 1/2 flame. A 55,000 BTU "should" be plenty, but bigger ones arent that much more if you may do keggles some day.