More fundamentally, chemical catalysts by definition are not consumed by the reactions they catalyze.
Think: a cheese grater. It doesn't react with the cheese, so a few ounces of grater could make hundreds of pounds of grilled cheese.
A hypothetical 300 tons of catalyst is not limited stoichiometrically to how much substrate it would affect.
More fundamentally, chemical catalysts by definition are not consumed by the reactions they catalyze.
Think: a cheese grater. It doesn't react with the cheese, so a few ounces of grater could make hundreds of pounds of grilled cheese.
A hypothetical 300 tons of catalyst is not limited stoichiometrically to how much substrate it would affect.