In 1914, William Leroy Emmett, a research engineer at General Electric, first proposed using mercury vapor instead of water vapor to rotate a turbine wheel. But scientists and engineers at the time argued that although the physical characteristics of mercury (boiling point, specific heat, etc.) make the idea theoretically possible, there are insurmountable obstacles to its implementation in practice.
However, Emmett refused to listen to the problems and "impossibility" and built an experimental setup. In his further work, T. G. Soren, vice president of the Hartford Electric Company, was so impressed with the results of Emmett's first tests that he struck a deal with him. And in 1923, an experimental 5,000 horsepower mercury plant was built and launched at the Dutch Point power plant.
There were predictable problems: the boiler head burst and the valuable mercury “ran away”, creating a loss of thousands of dollars. The turbine wheel fell apart and caused a stop for several months. The workers were poisoned by the fumes of toxic mercury. But no one was seriously hurt thanks to the unusual precautions the company took to protect people.
After revision and new tests, the company decided to build a mercury plant for real commercial use at its plant in Yuzhny Luga. South Meadow generated up to 143 kilowatt hours of electricity for every 100 pounds of coal burned. For comparison, the best steam power plant of the time produced only 112 kilowatt-hours of energy from this amount of coal. Ninety tons is the weight of the liquid mercury in the South Meadow boiler.
The plant consisted of seven forged steel drums, each containing 440 mild steel heat transfer tubes. The protruding ends of the pipes formed a “spiked” wall of the furnace chamber in which powdered coal was burned.
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Liquid mercury boiled in these pipes, the vapors moved through the pipe to a turbine connected to an electric generator. After the rotation of the turbine wheel, mercury vapors condensed and gave off the remaining heat to the water in the boiler, generating steam. This steam drives another turbine generator and the mercury, again in liquid form, is returned to the boiler through a reheater located in the furnace chamber. Mercury simply circulates in the system without being lost or consumed.
The power plants, designed by William Leroy Emmett, were built by General Electric and operated between 1923 and 1950. Large power plants were in Hartford, Connecticut, with a capacity of 1.8 MW (in 1922, and 15 MW in 1949). Generating station in Kearney, New Jersey, a 20 MW mercury turbine + 30 MW steam, started in 1933. Another in Portsmouth, New Hampshire, 40 MW. There are no such stations in operation today.
Based on the March 1931 issue of Popular Science magazine.
