Introduction

Gas turbines are high tech, high efficiency engines that convert chemical energy into work. Their high power to weight ratio make them the engine of choice for aircraft propulsion. Gas turbines are also at the heart of all modern gas fired power stations making electrical efficiencies above 60% possible. Beside the high power to weight ratio and the high cycle efficiency other advantages of gas turbines are the low emissions, the flexibility in operation and the applicability of the high grade waste heat either in a bottoming steam cycle or for industrial objectives.

Gas Turbine chair

The Gas Turbine chair at the department of Process and Energy of Mechanical Engineering (3ME) at the TU Delft has a long history in delivering high level education and world class research in the field of gas turbines. The chair is financially supported by the SGO (Stichting Gasturbine Onderwijs) and has excellent relationships with the Dutch and international gas turbine industry.

Research

The research field of gas turbines covers a broad range of engineering sciences that all come together in the gas turbine (system) design: aerodynamics, combustion, material engineering, thermodynamics, structural engineering, vibrations, controls, acoustics etc.

The research at the Gas Turbine chair focuses mainly on application of land based gas turbine (power generation and combined heat & power). The Gas Turbine chair has close cooperation with the other chairs within the Process and Energy Department, the Flight Performance and Propulsion department at Aerospace Engineering and the Materials Science and Engineering Department at 3ME.

The main research areas of the Gas Turbine chair are:

-          Flexibility of gas turbine operation

-          Alternative fuels & hydrogen combustion

-          Advanced high efficiency hydrogen-oxygen cycles

-          Impact of operations on gas turbine performance

Flexibility of gas turbine operation

The rapid growth of renewable generation has modified the role of combined cycle power stations. Due to the strong increase of intermittent renewable sources, (solar, wind) the key feature for the operational excellence of combined cycle power stations is flexibility.

Research themes are:

-          Part load efficiency improvement by external flue gas recirculation

-          Optimization of start up of gas turbine based installations using model based control, see Nannarone (2018) in Publications

-          Optimal configuration of low carbon and flexible combined heat and power installations, see Klein (2018) in Publications

Part load efficiency improvement by external flue gas recirculation

Part load efficiency for combined cycle and cogeneration installation can be improved by reduction of the stack losses by minimizing the air flow through the system. The standard way to minimize flow through a gas turbine, is the closure of the inlet guide vanes. An alternative approach is to preheat the inlet air. The free heat source for preheating are the exhaust gases from the stack.

The potential increase in efficiency is up to 18% for cogeneration installations and 5% for combined cycle installations. More information can be found in

The main challenge, next to prevention of condensation of water from the flue gases in the air inlet system, is the stability of combustion due the reduced oxygen concentration in the oxidizer (air mixed flue gas). The lower O2 concentration leads to lower NOx emissions both for premixed and non-premixed combustion. This will enable emission compliant operation at very low loads.

Please refer to the Publications from Prakash (2018) and Steimes (2018) and the MSc thesis by Prakash.

Alternative fuels & combustion

Due to the increasing focus on the reduction of carbon emissions in combination with the increasing share of renewable future land based gas turbine installations will run on other fuels like hydrogen or (waste) gases from biomass gasification. In the meantime the requirements with respect to NOx emissions will also become sharper.

Hydrogen is seen as an important “battery fuel” as excess energy produced by wind and solar can be used to produce hydrogen through electrolysis. The stored hydrogen will be converted back to power during periods with shortage of renewable energy production to ensure electrical grid stability with a zero carbon footprint. Gas turbine based power plants are very well positioned to convert the hydrogen back to power, because of their high efficiency (~60%), installed capacity and inherent flexibility.

Pertaining to gas turbine combustion, hydrogen is a highly reactive fuel and presents challenges for existing combustors to switch between natural gas and hydrogen while remaining stable and with NOx emissions always below stringent limits.

TU Delft cooperates in the HighHydrogen project with other companies on the development on a 100% premixed hydrogen gas turbine burner based upon the FlamesheetTM technology. The focus of TU Delft is on the development of a flash back model (see Publications).

TU Delft flashback model

The TU Delft has developed a boundary layer flashback model based on the boundary layer stability theory from Stratford. The model has shown to predict boundary layer flashback well .

The model can be coupled as a post processor to steady CFD calculations.

More information can be found in the Publications and in the MSc theses by Tober and Bjornson.

TU Delft hydrogen combustion laboratory

The Process & Energy has a state of the art atmospheric combustion laboratory. Hydrogen gas turbine combustion is one of the main focal research areas. Advanced laser diagnostics like PIV, PLIF, LDA and CARS are available.

Please refer to the thesis by Faldella about interesting features of hydrogen flames.

Research themes are:

-          Fully premixed hydrogen combustion in gas turbine applications

-          Application of biomass gasification gases

-          Thermo-acoustics

Advanced high efficiency hydrogen-oxygen cycles

Very high cycle efficiencies (up to 85%!) can be achieved in power cycles by using both the hydrogen and oxygen that are produced by electrolysis of water. These significantly higher efficiencies than the current state of the art of LHV efficiencies of around 60% are achieved by an advanced integrated thermodynamic cycle consisting of a fuel cell, Brayton cycle and Rankine cycle using hydrogen an oxygen as an input and pure water as an output.

 

 

 The Sankey diagram shows that the main losses occur due the thermodynamic irreversability’s in the Rankine and Brayton cycle.

 

The current research decribes the maximum theoretical potential. See e.g. MSc thesis from Schouten or ASME Turbo paper from Schouten in Publications.

We are now working on more realistic version of this cycle.

It is expected that these cycles can be applied in the future for powering large scale transportation like marine freight transport.

Impact of operations on gas turbine performance

The increased flexible operation and the application of other non-conventional fuels will have serious impact on the hardware and the performance of the gas turbine.

Research themes are:

-          Reducing stresses during CCGT power plant start up

-          Big data analysis and machine learning for asset performance improvement.

Publications

Journal publications

A. Gangoli Rao, F.S.C. van den Oudenalder, S.A. Klein,  Natural gas displacement by wind curtailment utilization in combined-cycle power plants. DOI:10.1016/j.energy.2018.11.119

A. Nannarone, S.A. Klein: Start-Up Optimization of a CCGT Power Station Using Model-Based Gas Turbine Control, Journal of Engineering for Gas Turbines and Power 10/2018; 141(4)., DOI:10.1115/1.4041273

M. del Grosso, B. Sridharanb, C. Tsekosa, S. Klein & W. de Jong, A modelling based study on the integration of 10 MWth indirect torrefied biomass gasification, methanol and power production, Biomass and Bioenergy, Vol 136 May 2020, https://doi.org/10.1016/j.biombioe.2020.105529

Bjornson, O.H., Klein, S.A. and Tober, J., Boundary layer flashback model for confined hydrogen flames including the effect of adverse pressure gradient flow, Journal of Engineering for Gas Turbines and Power 2020, GTP 20-415, https://doi.org/10.1115/1.4048566

Schöffer, S.I. , S.A. Klein, S.A.,  Aravind, P.V., Pecnik, R., A solid oxide fuel cell- supercritical carbon dioxide Brayton cycle hybrid system, Applied Energy, 2020, 115748, doi.org/10.1016/j.apenergy.2020.115748

Conference publications

S. Klein: ON THE IDENTIFICATION OF COMBUSTION INSTABILITY MECHANISMS IN INDUSTRIAL GAS TURBINE COMBUSTORS. 1st Global Power and Propulsion Forum, Zurich; 01/2017

V. Prakash, J. Steimes, D. J. E. M. Roekaerts, Sikke Klein: Modelling the Effect of External Flue Gas Recirculation on NOx and CO Emissions in a Premixed Gas Turbine Combustor With Chemical Reactor Networks. ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition, Oslo; 06/2018, DOI:10.1115/GT2018-76548

A. Nannarone, S.A. Klein: Start-up Optimization of a CCGT Power Station Using Model Based Gas Turbine Control. Proceedings of ASME Turbo Expo 2018 - The 2018 Turbomachinery Technical Conference & Exposition presented by the ASME International Gas Turbine Institute, Lillestrøm (Oslo), Norway; 06/2018, DOI:10.1115/GT2018-76230

S. Klein: Enabling efficient and low emissions deep part load operation of combined cycles and combined heat and power plants with external Flue Gas Recirculation. GPPS Forum 18 - Global Power and Propulsion Society, Zurich; 01/2018

S.A. Klein, F.van Deursen: Evaluation of the Optimum Hybrid Power to Heat Configuration for a Gas Turbine Based Industrial Combined Heat and Power Plant. ASME Turbo Expo 2019: Turbomachinery Technical Conference and Exposition; 06/2019, DOI:10.1115/GT2019-90946

Bjornson, O.H., Klein, S.A. and Tober, J., Boundary layer flashback model for confined hydrogen flames including the effect of adverse pressure gradient flow, ASME Turbo Expo 2020, GT 2020-14164

Schouten, B. and Klein, S.A. Hydrogen and oxygen fired turbine cycle optimization , ASME Turbo Expo 2020, GT 2020-14592

https://www.researchgate.net/profile/Johan_Steimes/publications

Education

The chair is responsible for the MSc course: Turbomachinery (ME45170, 4 ECTS). The course is delivered by Prof. Dr. Ir. S.A. Klein, Dr.Ir. R. Pecnik and Dr.V.Popovich

Contact

For more information, please contact professor Sikke Klein: s.a.klein@tudelft.nl