ALSTOM Power’s GT13E2 gas turbine has been successfully commissioned in a refinery residual oil gasification process (api Energia, Italy) operating on Medium Btu gas (GT13E2-MBtu). The modification of the standard GT13E2 to operate with MBtu fuel has resulted in an improvement in the performance of the GT13E2 to exceed 192 MW and 38% efficiency (simple cycle) at ISO conditions. The GT compressor has been upgraded to incorporate an extra-end stage to boost the pressure ratio to 17:1 and improve performance. Syngas from residual oil gasification has a typical volumetric composition of 45% H2, 48% CO and 7% CO2 and a lower heating value of 13.9 MJ/kg. This syngas has been diluted with N2 to reduce the heating value to 7 MJ/kg lowering reactivity and allowing partially premixed operation. In order to operate with syngas a redesign of the standard EV burners was necessary to deal with the associated high flame velocities and volume fluxes. The fuel injection for syngas operation was placed at the burner end and the gas injected radially inward to obtain inherently safe operation. The gas turbine demonstrated successful operation with both syngas and oil No. 2 fuels. At the standard dilution of 7MJ/kg NOx emissions are in the 20–25 vppm range and the CO emissions are below 5 vppm independent of load. The modified burners demonstrated safe operation on syngas with and without dilution of nitrogen in a tested LHV range from 6.8 to 14 MJ/kg. This behavior allows high flexibility of the entire power plant. Changeover from oil no. 2 to syngas and vice versa can be done between 50 and 100% load. The gas turbine components have been inspected several times during the commissioning period and shown to be in good condition.

This paper describes the development and test results of the low emission combustion system for the new industrial gas turbines in the 6–7 MW class from MAN Diesel & Turbo. The design of a robust combustion system and the achievement of very low emission targets were the most important design goals of the combustor development. During the design phase, the analysis of the combustor (i.e. burner design, air distribution, liner cooling design) was supported with different CFD tools. This advanced Dry Low Emission can combustion system (ACC) consists of 6 cans mounted externally on the gas turbine. The behavior and performance of a single can sector was tested over a wide load range and with different boundary conditions; first on an atmospheric test rig and later on a high pressure test rig with extensive instrumentation to ensure an efficient test campaign and accurate data. The atmospheric tests showed a very good performance for all combustor parts and promising results. The high pressure tests demonstrated very stable behavior at all operation modes and very low emissions to satisfy stringent environmental requirements. The whole operation concept of the combustion system was tested first on the single-can high pressure test bed and later on twin and single shaft gas turbines at MAN’s gas turbine test facility. During the engine tests, the can combustors demonstrated the expected combustion performance under real operation conditions. All emissions and performance targets were fully achieved. On the single shaft engine, the combustors were running with single digit ppm NOx levels between 50% and 100% load. The validation phase and further optimization of the gas turbines and the engine components are ongoing. The highlights of the development process and results of the combustor and engine tests will be presented and discussed within this paper.

MAN Diesel & Turbo has developed a new gas turbine in the 6 MW-class for both mechanical drive and power generation applications. The lay-out of the Gas Turbine has been driven by opportunities in current and future markets and the positioning of the competition, and this has determined the characteristics and technical parameters which have been optimized in the 6 MW design. The design makes use of extremely high precision engineering so that the assembly of sub components to modules is a smooth flowing process and can guarantee both the high standards in quality and performance which MAN Diesel & Turbo is aiming for. Individual components have been tested and thoroughly validated. These tests include in particular the compressor of the gas turbine and the combustion chamber. The commissioning of the gas turbine prototype engine had been prepared with a numerous number of measuring probes and carried out at the Oberhausen plant gas turbine test field. Results of component and the gas turbine prototype tests will be presented and discussed.

In this paper a semi-empirical method is presented to predict the NOX emission of a pilot stabilized, technically premixed gas turbine combustor for arbitrary combustor inlet conditions. The method is based on measurement data for a reference operation cycle and ISO ambient condition. A model based correction function is used to account for the change of NOX emission, which results from combustor inlet condition and/or operation cycle deviating from reference data. The proposed method assumes that a pilot stabilized, technically premixed flame can be simplistically modeled as two separate combustion regimes: An assumed perfectly premixed regime, and an assumed diffusion flame regime. The emission of the combustor is then modeled as a superposition of the emissions from both individual combustion regimes. The emissions from the diffusion flame regime are the dominant contribution, although only a comparably small share of fuel is burnt in this regime. The emission of the perfectly premixed combustion regime can be modeled as a sole function of flame temperature. On the other hand, the emissions from the diffusion regime are strongly affected by combustor inlet pressure and temperature, which are in turn a function of the gas turbine operation cycle and inlet conditions. To simplify matters, only the change in NOX emission from the diffusion regime, which results from deviation of combustor inlet pressure and/or temperature from values expected for a reference operation cycle and ISO ambient condition, is modeled. NOX emission data for this reference operation cycle is necessary experimental input for the method. The proposed method can — with minimum experimental input — predict the NOX emission of a pilot stabilized, technically premixed combustor with good accuracy for arbitrary engine operation cycles and inlet conditions. It is aimed at providing reliable NOX emission estimates without the need for time intensive CFD or expensive experimental investigations. Typical applications are the assessment of a gas turbine’s NOX potential for feasibility studies of new operation or engine concepts with a proven combustor design, and for NOX estimates for out-of-experience ambient or site conditions for existing engines.

Industrial gas turbines like the MGT6000 are often operated as power supply or as mechanical drives. In these applications, liquid fuels like 'Diesel Fuel No.2' can be used either as main fuel or as backup fuel if natural gas is not reliably available. The MAN Gas Turbines (MGT) operate with the Advanced Can Combustion (ACC) system, which is capable of ultra-low NOx emissions for gaseous fuels. This system has been further developed to provide dry dual fuel capability. In the present paper, we describe the design and detailed experimental validation process of the liquid fuel injection, and its integration into the gas turbine package. A central lance with an integrated two-stage nozzle is employed as a liquid pilot stage, enabling ignition and start-up of the engine on liquid fuel only. The pilot stage is continuously operated, whereas the bulk of the liquid fuel is injected through the premixed combustor stage. The premixed stage comprises a set of four decentralized nozzles based on fluidic oscillator atomizers, wherein atomization of the liquid fuel is achieved through self-induced oscillations. We present results illustrating the spray, hydrodynamic, and emission performance of the injectors. Extensive testing of the burner at atmospheric and full load high-pressure conditions has been performed, before verification within full engine tests. We show the design of the fuel supply and distribution system. Finally, we discuss the integration of the dual fuel system into the standard gas turbine package of the MGT6000.