US scientists have designed an experimental gas turbine simulator that is equipped with an ultralow-emissions combustion technology, called the Low Swirl Injector (LSI), and which uses pure hydrogen as a fuel.
Researchers say this is a milestone that indicates a potential to help eliminate millions of tons of carbon dioxide and thousands of tons of NOx from power plants each year.
The LSI designed at the US Department of Energy's Lawrence Berkeley National Laboratory is a mechanically simple device that has no moving parts. It imparts a mild spin to the gaseous fuel and air mixture that causes the mixture to spread out. The flame is stabilized within the spreading flow just beyond the exit of the burner.
According to the design team, not only does this make the flame stable, but it also burns at a lower temperature than that of conventional burners.
The production of nitrogen oxides is highly temperature-dependent, and the lower temperature of the flame reduces emissions of nitrogen oxides to very low levels.
"The LSI principle defies conventional approaches. Combustion experts worldwide are just beginning to embrace this counter-intuitive idea. Principles from turbulent fluid mechanics, thermodynamics, and flame chemistry are all required to explain the science underlying this combustion phenomenon," said Robert Cheng.
Chang designed the LSI together with Berkeley colleagues David Littlejohn, and Kenneth Smith and Wazeem Nazeer from Solar Turbines Inc. San Diego.
Tests at Berkeley Lab and Solar Turbines further showed that the burners with LSI emitted lower levels of NOx (five times less) compared to conventional turbines.
Another advantage, the research team said, is the technology's ability to burn a variety of different fuels from natural gas to hydrogen and the relative ease to incorporate it into current turbine design.