Less than 10 ppm, down to 50 percent load

MAN Diesel & Turbo recently said it has managed to reduce the nitrogen oxide emissions of their new MGT gas turbine generation to an extremely low level in test stand runs. The new gas turbine is expected to be not only highly efficient, but also particularly low in pollution.

Less than 10 ppm nitrogen oxide (parts per million, of the total volume) were said to be detected in the exhaust gas on the test stand in Oberhausen during all operating conditions between half and full performance of the gas turbine. In comparison, the German Federal Immission Control Act currently specifies a limit value of 36.5 ppm (equivalent to 75mg/Nm3) in the ‘Technical Instructions on Air Quality Control (TA Luft)’.

The new gas turbine generation with six to eight MW output is expected to have a great potential to drive the energy revolution forward. The turbines can supposedly be started up comparatively faster with values of under-10 minutes and can ideally supplement strongly fluctuating renewable energy sources such as wind or solar power as generator drives. Funding was received for development of the new gas turbine under the North Rhine-Westphalia Objective 2 Programme 2007-2013 ‘Regional Competitiveness and Employment (ERDF)’.

Dr. Sven-Hendrik Wiers, Vice President Gas Turbines said, "One of our primary development aims was that the new gas turbine family had to be equally economic and environmentally-friendly all the way down the line. The single digit NOx values now realized in the load range between 50 and 100 percent with the MGT 6100, the single-shaft version of the new MGT gas turbine family, impressively prove that we have achieved this aim."

According to Frank Reiss, Head of Combustion Technology, the manufacturers are convinced that they can repeat the result in further versions of the same type. Further plans are to offer a guarantee on very low nitrogen oxide values based on the test results, thereby increasing the competitiveness of the gas turbine, he said. The development department in Oberhausen is said to have achieved these extremely low emission values with an ACC combustion chamber modified and further developed for the new gas turbine generation.

MAN Diesel & Turbo has already developed and implemented an Advanced Can Combustor (ACC) for their THM gas turbine family. These can-type combustion chambers work on the principle of premix technology. The fuel is already premixed homogeneously with the combustion air before entering the combustion chamber. The result: Fuel-rich hot strands are avoided. This means that significantly less nitrogen oxides, which are harmful to both living beings and plants at higher concentrations, are formed in the exhaust gas.

Dr. Wiers. SolVin, the first customer to put into operation a two-shaft MGT 6200 at their Rheinberg site at the end of June, said, "It is particularly important that we have achieved low nitrogen oxide emissions in a wide load range. It is exactly this flexibility that will be in demand in future, especially for decentralized power generation." As a cogeneration system (CHP), it produces power and process heat for the manufacturer of basic chemicals, with a total efficiency of over 80 percent.