Combustion converter design evolution

The early thermionic converters used hemispherical one-inch-diameter hot shells. They were extensively tested in a natural gas, high-temperature furnace. A converter was life tested for 12,500 hours at emitter temperatures above 1700 K. Two-inch diameter converters with both hemispherical and torispherical shapes were developed next. These converters have been tested in both natural gas-, oil-, and coal-oil slurry-fired environments. A prototype converter for cogeneration applications was also developed using this emitter configuration. A six converter module of cogeneration converters has been constructed