The calculation is correct. 5 million tons per year is 100,000 barrels per day.
That is not what is burning. That is the amount offline until the burning stops which apparently takes a few days.
Curious if Ukraine is getting better at hitting critical areas of refineries such as cracking towers. Replacing lost oil and oil tanks would be costly, but if critical refining infrastructure is hit, that, I imagine, would be far more expensive and difficult to repair or replace especially if much of it is western equipment and technology