What is the difference between a high-mounted fuel tank and a parking fuel tank?

The high-position oil tank is primarily used to ensure lubrication and cooling of the unit during shutdown due to abnormal circumstances that result in the shutdown of the circulation oil pump, thereby maintaining safety.

I’ve never heard of a “parking fuel tank”; it’s probably just another name for a high-mounted fuel tank. The high-level oil tank is one of the safety protection devices for steam turbine units. The normal supply of oil to the turbine is provided by the main oil pump; in the event of a power outage that causes the turbine to stop, the auxiliary oil pump cannot start up in time to supply oil. However, the turbine continues to rotate due to its inertia, which increases the risk of bearing damage. To prevent such accidents, a high-level oil tank is installed; in this way, the lubricating oil flows through the inlet pipelines, passes through each bearing, and then returns to the main oil tank. This ensures an adequate supply of lubricating oil during the unit’s coasting phase, thereby guaranteeing a safe shutdown of the unit. The fuel storage capacity of the tank must be sufficient to meet the idling time requirements of the unit; therefore, this needs to be confirmed by the turbine manufacturer or the design institute.