A fuel analysis report for a gas turbine propelled vessel indicates a calcium level in excess of 0.5 ppm. High calcium levels in distillate fuels for gas turbines can cause which of the following?

Correct Answer: Option C — Calcium deposits which can clog cooling holes in the turbine section.

Calcium, often present in fuel as a contaminant, reacts with sulfur during combustion to form calcium sulfate. These compounds have high melting points and deposit on turbine blades and nozzles, specifically clogging the intricate film-cooling holes designed to protect turbine components from extreme gas temperatures, leading to localized overheating.