For optimum results, centrifugal purification of heavy fuel oil should be accomplished with the fuel at the lowest practicable __________.

Correct Answer: Option A — throughput

Centrifugal purification efficiency is inversely related to throughput. Reducing the flow rate increases the residence time within the bowl, allowing more time for the centrifugal force to act upon fine particles and water droplets. Lowering throughput ensures the highest possible degree of separation for heavy fuel oil.