Kawasaki Heavy Develops New Gas Turbine Combustion Technology for Record Low NOx Emissions of 15 ppm
Kawasaki Heavy Industries, Ltd. (KHI) has developed a new gas turbine combustion technology for its proprietary dry low emission (DLE) combustion system used mainly in natural gas-fired turbines. This development in premix combustion technology has enabled Kawasaki to build a gas turbine with the lowest NOx emissions yet.
Kawasaki has successfully lowered the guaranteed maximum NOx emissions level of its 7 MW-class M7A-03 gas turbines from 25 ppm to an all time low of 15 ppm (converted at 15% O2). This is a milestone achievement for DLE combustion systems of this class, according to KHI.
NOx is generated during the gas turbine fuel combustion process and released into the atmosphere. The amount of NOx generated largely depends on combustion temperature. DLE combustors employ a premix combustion method that minimizes combustion temperature without the use of injected water or steam by premixing the fuel with air.
Since they provide an economical solution that significantly reduces NOx emissions, DLE combustors are employed in most gas turbines. The big problem with premix combustion, especially when used to lower NOx emissions, is that it is unstable. This had always been a major technological stumbling block to lowering DLE combustor NOx emissions.
Kawasaki focused on combining premix with supplemental burners, enabling combustion stability. This latest lowering of NOx emissions is built on a solid foundation of DLE combustor R&D. Kawasaki has leveraged the technological expertise it has gained over the years to upgrade the burners and develop a compact recombustion burner with enhanced mixing performance.
Since stationary gas turbines emit NOx gasses that result in photochemical smog and acid rain, they are subject to strict regulations across the globe. An increasing number of local governments in the US and Europe, where public awareness about preserving air quality is high, are implementing even stricter NOx emissions standards that lower the acceptable emissions level from 25 ppm to 15 ppm. These new regulations are seen as just the beginning of a growing trend.
Kawasaki is working to develop new types of DLE combustion systems with a guaranteed maximum NOx emissions level of 15 ppm for its other major models and plans to launch them onto the market in the near future.
NOx emissions regulations are likely to become even stiffer, with requirements for less than nine-ppm NOx emissions looming over the horizon. To meet these increasingly tougher NOx emissions standards, Kawasaki is moving ahead with R&D efforts that build on the low NOx combustion technology employed in its DLE combustion systems boasting a NOx emissions level of less than 15 ppm.