An assessment of the thermodynamic performance of mixed gas-steam cycles. Part B: Water-injected and HAT cycles
- Politecnico di Milano, Milan (Italy). Dipartimento di Energetica
Part B of this paper focuses on intercooled recuperated cycles where water is injected to improve both efficiency and power output. This concept is investigated for two basic cycle configurations: a Recuperated Water Injected (RWI) cycle, where water is simply injected downstream of the HP compressor, and a Humid air Turbine (HAT) cycle, where air/water mixing is accomplished in a countercurrent heat/mass transfer column called ``saturator.`` For both configurations the authors discuss the selection and the optimization of the main cycle parameters, and track the variations of efficiency and specific work with overall gas turbine pressure ratio and turbine inlet temperature (TIT). TIT can vary to take advantage of lower gas turbine coolant temperatures, but only within the capabilities of current technology. For HAT cycles they also address the modelization of the saturator and the sensitivity to the most crucial characteristics of novel components (temperature differences and pressure drops in heat/mass transfer equipment). The efficiency penalties associated with each process are evaluated by a second-law analysis, which also includes the cycles considered in Part A. For any given TIT in the range considered (1,250 to 1,500 C), the more reversible air/water mixing mechanism realized in the saturator allows HAT cycles to achieve efficiencies about 2 percentage points higher than those of RWI cycles: At the TIT of 1,500 C made possible by intercooling, state-of-the-art aero-engines embodying the above-mentioned cycle modifications can reach net electrical efficient of about 57 and 55 percent, respectively. This compares to efficiencies slightly below 56 percent achievable by combined cycles based upon large-scale heavy-duty machines with TIT = 1,280 C.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 109814
- 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
Similar Records
Design and off-design performance of advanced mixed gas-steam cycle power plants
A modified, high-efficiency, recuperated gas turbine cycle