Session: 06-11 Innovations in Steam and Bottoming Cycles

Submission Number: 178243

A New Concept of Steam-Injection Inverted Gas Turbines for Efficient Power Generation From High-Temperature Waste Gases 

High-temperature waste heat gases form a significant barrier to the sustainable development of energy and industrial sectors, as large amounts of energy are discharged to the environment. At the same time, these gases represent a recoverable heat source for power-generating cycles. However, the concrete temperature of this heat source follows from the characteristics of the given waste heat stream. Yet, the thermodynamic efficiency can still be enhanced by formulating the cycle systematically from fundamental thermodynamic principles.

This paper proposes a new concept for improving the efficiency of inverted gas turbines through ejector-assisted steam injection. Hereby, the flow of high-temperature waste gases enters an ejector, where it is compressed using high-pressure and high-temperature steam. The resulting high-temperature and high-pressure mixture of gases and steam expands to sub-atmospheric pressure in a turbine, generating power. The low-pressure mixture is cooled firstly in steam-generating heat exchangers and then in an additional heat exchanger. This additional heat exchanger is proposed to cool the wet waste gases below the dew point temperature, where the injected steam condenses. This allows a reduction in the flow rate of the turbocompressor, resulting in a decrease in its power consumption to exhaust the gas from the vacuum into the environment at atmospheric pressure. Finally, the condensed water is pressurized in a pump and, afterwards, is heated and evaporated in the steam-generating heat exchangers.

A thermodynamic model of the system is developed, and its performance is analyzed under varying conditions for the waste gas inlet temperature, vacuum intensity, and steam injection fraction. Results are presented to show their influence on the generated power and efficiency, as well as the interdependencies among these parameters. Recommendations are provided for the parameters of vacuum and steam that maximize the power increase, thereby guiding efficient power generation from high-temperature waste gases. In this context, the study makes a broader scientific contribution by establishing a conceptual framework applicable to advanced cycle investigations for the systematic integration of waste heat.

Presenting Author: Maja Sharevska Department of Thermal and Fluid Engineering, Faculty of Engineering Technology, University of Twente

Presenting Author Biography: Maja Sharevska is a PhD Candidate at the Department of Thermal and Fluid Engineering, University of Twente. Her research focuses on the systematic integration of energy conversion technologies in distributed multi-energy systems. Her recent work explores thermodynamic cycle innovations for industrial waste heat recovery. She holds a MSc in Mechanical Engineering from Saints Cyril and Methodius University in Skopje, Macedonia.

Authors:

Maja Sharevska Department of Thermal and Fluid Engineering, Faculty of Engineering Technology, University of Twente
Monika Sharevska Department of Thermal and Fluid Engineering, Faculty of Engineering Technology, University of Twente
Gerrit Brem Department of Thermal and Fluid Engineering, Faculty of Engineering Technology, University of Twente
Gerwin Hoogsteen Faculty of Electrical Engineering, Mathematics and Computer Science, University of Twente
Johann Hurink Faculty of Electrical Engineering, Mathematics and Computer Science, University of Twente
Yashar Hajimolana Department of Thermal and Fluid Engineering, Faculty of Engineering Technology, University of Twente