Mercury_vapour_turbine
A mercury vapour turbine is a form of heat engine that uses mercury as the working fluid of its thermal cycle. A mercury vapour turbine has been used in conjunction with a steam turbine[1] for generating electricity. This example of combined cycle generation was not widely adopted, because of high capital cost and the obvious toxic hazard if the mercury leaked into the environment.
The mercury cycle offers an efficiency increase compared to a steam-only cycle because energy can be injected into the Rankine cycle at higher temperature. Metallurgical developments have allowed steam-only plants to increase in efficiency over time, making the mercury vapour turbine obsolete. Modern combined cycle power plant generating stations operate at 61% efficiency, and with none of the safety issues inherent to a binary mercury Rankine cycle steam power plant.