Session: 20-01 Compressor and Gas Turbine Development and Testing

Paper Number: 120965

120965 - Gas Turbine Drives for Pipeline-Compressors: Assessing the Influence of H2-Blends on Performance, Load Dynamics, and Emissions of a Gas Turbine With DLE Technology in a Real-World Field-Study 

Amidst the development of energy concepts, hydrogen is a promising energy carrier that can shape a sustainable energy supply for the future. During the transition phase of replacing natural gas with hydrogen, it becomes crucial for the gas infrastructure to adeptly manage a wide array of hydrogen/natural gas blends while ensuring safety, availability, and efficiency. Until now, compressors are predominantly driven by gas turbines, which use the conveyed gas as fuel. With the increasing importance of integrating hydrogen into the natural gas grid, plant equipment, in particular gas turbines with dry-low-emission (DLE) combustion systems, must undergo comprehensive testing for their hydrogen compatibility.

For this purpose, a test operation using a 15 MW gas turbine equipped with DLE combustion technology was conducted within the framework of a locally defined part of the natural gas grid. The gas turbine was equipped with special-purpose measurement instruments, e.g., additional thermocouples, to meet monitoring requirements. The test operation was performed within a collaboration of transport system operators MEGAL JV (OGE, GRTgazDeutschland)and GRTgaz, and the OEM Solar Turbines. The modified gas turbine was operated with natural gas/hydrogen mixtures containing hydrogen concentrations between 0 and 25 vol%. The natural gas/hydrogen mixture was supplied and controlled by a blending unit specifically developed for this test by OGE.

This work focuses on technical and project-related aspects of the conducted field study, considering established methods and policies to ensure safe operation (HAZOP, ATEX), the methodology for commissioning, and finally, the execution of continuous operation. In particular, the novel blending unit based on a turbulent-mixing chamber and its associated control concept are examined with respect to the ability to maintain temperatures, pressures, and H₂-fractions on demand. Furthermore, greater emphasis is placed on the modification and operation of the gas turbine. Moreover, the behavior of the gas turbine when operating with various H₂-blends is investigated, assessing its performance in continuous and transient operation, as well as its emissions profile and the activation of the DLE mode.

The comprehensive testing performed under various H₂ and load variations yielded several findings. Firstly, the novel blending unit demonstrated the capability to continuously provide H₂/natural gas mixtures of up to 25% H₂ maintaining a deviation of 5% between setpoint and the measured value recorded for verification by gas chromatography. Secondly, the tests revealed maximum thermal efficiencies between 35% (0% H₂) and 36% (25% H₂) and slightly reduced fuel consumption at full load, confirming the marginal impact of H₂-addition in the investigated range on the overall performance. Additionally, carbon-based emissions, such as CO, are negligible with increasing H₂-blend. Instead, NOx emissions increased with increasing H₂ fraction, however, compliance with the mandatory emission limits is ensured. It must be noted that the activation of the dry-low-emission mode associated with the control of the fuel flow through the main and pilot burner is possible with any H₂-blend studied. Transient operation, especially during fast load changes, were impacted by the H₂-blend, leading to an extended settling period of up to 300 seconds. Moreover, the test proved the mechanical integrity of the gas turbine as dynamic parameters, e.g., shaft and casing vibration, remained well below best-practice limits established by the OEM throughout and no emergency shutdown occurred. In addition, the post-test boroscopic examination revealed no surface changes on the inspected parts. In summary, the test impressively demonstrated the suitability of the gas turbine for use as a drive in the natural gas grid with H₂ mole fractions of up to 25% within a real-world scenario.

Presenting Author: Charlotte Rudolph Open Grid Europe GmbH

Presenting Author Biography: Dr.-Ing. Charlotte Rudolph,
Project Engineer for Rotating Equipment
Open Grid Europe GmbH, Germany

Ms. Charlotte Rudolph did her Ph.D. at the University of Duisburg-Essen in the field of Thermodynamics and Reaction Kinetics. She has experience in the thermodynamic and kinetic analysis of heat engines operating under alternative conditions, in particular energy storage and carbon dioxide utilization conditions. In her current role at Open Grid Europe, Ms. Rudolph is workin in the field of rotating machinery such as gas turbines, turbo-compressors and related equipment.
She will present "Gas Turbine Drives for Pipeline Compressors: Assessing the Influence of H2-Blends on Performance, Load Dynamics, and Emissions of a Gas Turbine With DLE Technology in a Real-World Field-Study," providing valuable insights into the impact of H2 on gas turbine drives from the perspective of a transmission system operator.

Authors:

Charlotte Rudolph Open Grid Europe GmbH
Maurizio Sciancalepore Open Grid Europe GmbH
Deborah Vesper Open Grid Europe GmbH
Tobias Schiffer Open Grid Europe GmbH
Francis Bainier GRTgaz
Thorsten Lauzat Open Grid Europe GmbH