New Ultra-Low Emissions Combustion Technology Developed
It sounds almost too good to be true: just drop the device - dubbed the low-swirl injector (LSI) - into any old gas-burning turbine and watch it achieve low emissions of carbon dioxide and near-zero emissions of nitrogen oxides (NOx). Yet this revolutionary combustion technology - developed jointly by a team of scientists from the Lawrence Berkeley Lab and one from San Diego-based Solar Turbines Inc. - did just that in a recent test using pure hydrogen as a fuel. If incorporated into existing power plants, it could help eliminate thousands of tons of NOx and millions of tons of carbon dioxide every year.
The LSI works by imparting a slight spin to the gaseous fuel and air mixture placed in the gas turbine, causing it to spread out. This helps stabilize the flame used to heat the mixture and, more importantly, allows it to burn at lower temperatures. Since the production of NOx is highly temperature-dependent, the lower flame temperature drastically reduces the level of emissions produced. Natural gas-burning turbines equipped with the LSI emitted 2 ppm of NOx, more than 5 times less the amount emitted by conventional burners.It can also burn a variety of other fuels - including hydrogen - and can easily be fitted into existing gas turbine models without any major redesigns. Further research is being conducted to make carbon-neutral renewable fuels - such as those from landfills and waste treatments - also compatible with the technology.
"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 of the DOE's Lawrence Berkeley National Laboratory, one of the device's inventors.
The DOE has high hopes for the LSI: it is now actively testing it for its ability to burn syngas - a mixture of hydrogen and carbon monoxide - and hydrogen fuels to see whether it could be incorporated into the world's first near-zero emissions coal power plant, FutureGen. The LSI is one among several combustion technologies being evaluated for use in the plant's 200+ MW utility-size hydrogen turbine.