An assessment of the thermodynamic performance of mixed gas-steam cycles. Part A: Intercooled and steam-injected cycles
- Politecnico di Milano, Milan (Italy). Dipartimento di Energetica
This paper discusses the thermodynamics of power cycles where steam or water are mixed with air (or combustion gases) to improve the performance of stationary gas turbine cycles fired on clean fuels. In particular, the authors consider cycles based on modified versions of modern, high-performance, high-efficient aeroderivative engines. The paper is divided into two parts. After a brief description of the calculation method, in Part A the authors review the implications of intercooling and analyze cycles with steam injection (STIG and ISTIG). In Part B they examine cycles with water injection (RWI and HAT). Due to lower coolant temperatures, intercooling enables us to reduce turbine cooling flows and/or to increase the turbine inlet temperature. Results show that this can provide significant power and efficiency improvements for both simple cycle and combined cycle systems based on aero-engines; systems based on heavy-duty machines also experience power output augmentation, but almost no efficiency improvement. Mainly due to the irrepressibilities of steam/air mixing, intercooled steam injected cycles cannot achieve efficiencies beyond the 52--53 percent range even at turbine inlet temperatures of 1,500 C. ON the other hand, by accomplishing more reversible water-air mixing, the cycles analyzed in Part B can reach efficiencies comparable (RWI cycles) or even superior (HAT cycles) to those of conventional ``unmixed`` combined cycles.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 109813
- Report Number(s):
- CONF-940626--
- Journal Information:
- Journal of Engineering for Gas Turbines and Power, Journal Name: Journal of Engineering for Gas Turbines and Power Journal Issue: 3 Vol. 117; ISSN JETPEZ; ISSN 0742-4795
- Country of Publication:
- United States
- Language:
- English
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