Steam-Injected Gas Turbines

1987 ◽  
Vol 109 (1) ◽  
pp. 55-63 ◽  
Author(s):  
E. D. Larson ◽  
R. H. Williams
Keyword(s):  
Gas Turbines ◽  
High Efficiency ◽  
Steam Injection ◽  
Capital Cost ◽  
Part Load ◽  
Economic Significance ◽  
Commercial Technology ◽  
Combined Cycles ◽  
Injection Technology ◽  
Central Station

Among cogeneration and central station power generating technologies, gas turbine systems are attractive largely because of their low capital cost and simplicity. However, poor part-load efficiencies have restricted simple-cycle gas turbines largely to base-load cogeneration applications, while relatively low efficiencies for the production of power only have restricted gas turbines largely to peaking central station applications. Steam-injected gas turbines overcome cogeneration part-load problems by providing for steam in excess of process requirements to be injected into the combustor to raise electrical output and generating efficiency. For central station applications, proposed steam-injected gas turbines would achieve higher efficiencies at smaller capacities than any existing commercial technology, including combined cycles. Their high efficiency and expected low capital cost would make them highly competitive for baseload power generation. This paper provides an overview of steam-injection technology, including performance calculations and an assessment of the economic significance of the technology for cogeneration and central station applications.

Water Recovery Systems for Steam-Injected Gas Turbines: Size Optimization and Life Cycle Savings

2002 ◽  
Author(s):  
Gabriel Blanco ◽  
Lawrence L. Ambs
Keyword(s):  
Environmental Impacts ◽  
Gas Turbines ◽  
Steam Injection ◽  
Economic Feasibility ◽  
Operating Costs ◽  
Exhaust Gas ◽  
External Costs ◽  
Water Recovery ◽  
Power Requirement ◽  
Injection Technology

Steam injection in gas turbines has been used for many years to increase the power output as well as the efficiency of the system and, more recently, to reduce the formation of NOx during the combustion. The major drawback in steam-injection technology is the need of large amounts of fresh water that is eventually lost into the atmosphere along with the exhaust gas. This loss not only increases the operating costs of the system, but also creates other “external” costs in terms of environmental impacts. In order to take advantage of the steam-injection technology and reduce both operating costs and potential environmental impacts, water recovery systems to recuperate the injected steam from the exhaust gas can be implemented. This paper briefly describes the computer models developed at the University of Massachusetts Amherst to optimize water recovery systems. As an example, the optimum size, power requirement and capital cost for two different systems applied to the GE LM2500 gas turbine are shown. Finally, a comparative economic analysis between the costs of installing and operating a water recovery system and the costs of buying and treating water on a regular basis during the lifetime of the project is presented. The results support the economic feasibility of water recovery for mid-size steam-injected gas turbines before having introduced the external costs associated with the use of water resources.

scholarly journals Externally Fired Combined Cycles (EFCC): Part B — Alternative Configurations and Cost Projections

1996 ◽  
Author(s):  
Stefano Consonni ◽  
Ennio Macchi
Keyword(s):  
High Temperature ◽  
Heat Exchangers ◽  
Gas Turbines ◽  
High Efficiency ◽  
Complete Combustion ◽  
Economic Issues ◽  
Temperature Heat ◽  
Combined Cycles ◽  
Power Outputs ◽  
The Cost

Externally Fired Combined Cycles (EFCC) constitute one of the options allowing the use of “dirty” fuels like coal, biomass or waste in conjunction with modern, high efficiency gas turbines. This two-part paper discusses thermodynamic, technological and economic issues crucial to the successful realization of EFCCs. Part B discusses the cycle arrangement, its implications for the design and the cost of the high temperature heat exchangers, the effects of scale and the economic prospects. An “enhanced” configuration whereby the excess air sent to the combustor is limited to the minimum required for complete combustion can reach net LHV efficiencies above 50%, with relatively low high-temperature heat transfer surface requirements. Cost projections are hindered by the uncertainty on the cost of the high temperature heat exchangers. Estimates based on published and proprietary data collected by the authors indicate that EFCCs should be cost-competitive with IGCCs, especially at medium-low power outputs.

scholarly journals Externally Fired Combined Cycles (EFCC): Part A — Thermodynamics and Technological Issues

1996 ◽  
Author(s):  
Stefano Consonni ◽  
Ennio Macchi ◽  
Francesco Farina
Keyword(s):  
Atmospheric Pressure ◽  
Gas Turbines ◽  
Large Scale ◽  
High Efficiency ◽  
Combined Cycle ◽  
Indirect Contact ◽  
Economic Issues ◽  
Combustion Gases ◽  
Combined Cycles ◽  
Gas Turbine Compressor

Externally Fired Combined Cycles (EFCC) are one of the options allowing the use of “dirty” fuels like coal, biomass or waste in conjunction with modern, high efficiency gas turbines. The plant concept comprises an indirect-contact ceramic heat exchanger where compressed air exiting the gas turbine compressor is heated by hot combustion gases; the combustor is placed downstream the turbine and operates at nearly atmospheric pressure. From a thermodynamic standpoint, the cycle is equivalent to a combined cycle with supplementary firing. Attainable efficiencies are higher than those achievable by steam cycles (even the most advanced ultra-supercritical), as well as those of most other coal-based technologies (PFBC and IGCC). These efficiency advantages must be weighted against the uncertainty (and risk) of the realization of high temperature ceramic heat exchangers, and the challenges for the design of the combustor. This two-part paper discusses thermodynamic, technological and economic issues crucial to the success of EFCCs, both for large scale utility service (3–400 MWe1 and more) and for medium/low scale applications (down to 30–50 MWe1). Part A addresses the most relevant thermodynamic and technological issues, performing comparisons with the technologies which will presumably dominate the coal-based power generation market of the next century.

New Cycles for Methanol-Fuelled Gas Turbines

1987 ◽  
Author(s):  
M. M. S. Klaeyle ◽  
R. Laurent ◽  
F. Nandjee
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Nuclear Power ◽  
Power Plants ◽  
Steam Injection ◽  
Energy System ◽  
Capital Cost ◽  
Maximum Heat ◽  
Steam Reforming Of Methanol ◽  
Cumulative Duration

Assuming that methanol is employed as fuel, the heat released from the gas turbine discharges can be used to cause an endothermic catalytic reaction: CH3 OH + H2 O + heat → 0,5 CO + 0,5 CO2 + 2,5 H2 + 0,5 H2 O; this produces a gaseous fuel, the lower heaving value of which exceeds that of methanol by 18%. Combining both steam reforming of methanol and steam injection in the combustor by using the maximum heat available in the exhaust gases, very interesting cycle characteristics can be achieved (more than 50% efficiency (LHV basis), same capital cost per kW as simple cycle gas turbine (9000E engine), low emissions of NOx and SO2). Reheating the gas during the expansion will improve the efficiency by 2–3 points allowing an increase in power output without increasing the capital cost per kW. At the end of the century, these types of cycles could be applied to all the new, non-nuclear power plants in the French energy system. The annual cumulative duration of such generators will not be greater than 2000 hours.

Economic Assessment of Evaporative Gas Turbine Cycles With Optimized Part Flow Humidification Systems

2003 ◽  
Author(s):  
Maria Jonsson ◽  
Jinyue Yan
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Economic Assessment ◽  
Steam Injection ◽  
Cost Of Electricity ◽  
Specific Investment ◽  
Combined Cycles ◽  
The Cost ◽  
Flow Case

This study is an economic assessment of evaporative and steam-injected cycles based on three gas turbines (Trent, GTX100 and Cyclone). The evaporative cycles included part or full flow humidification and steam injection. For the Trent and GTX100, part flow cases had the lowest costs of electricity (32.6 mills/kWh and 30.9 mills/kWh, respectively), while a full flow case had the lowest cost of electricity (35.3 mills/kWh) for the Cyclone. However, the cost variations between different cycles were small: below 1% (0.4 mills/kWh) for the GTX100 and Cyclone cases and below 3% (0.9 mills/kWh) for the Trent cases. The specific investment costs were lower for part flow evaporative cycles than for full flow cycles, while steam-injected cycles had the lowest specific investment costs. The Trent and GTX100 evaporative cycles had significantly lower total and specific investment costs than combined cycles, while the costs of electricity were approximately the same.

scholarly journals Performance Modeling of Aeroderivative Steam-Injected Gas Turbines and Combined Cycles Fueled From Fixed or Fluid-Bed Biomass Gasifiers

1996 ◽  
Author(s):  
Eric D. Larson ◽  
Wendy E. M. Hughes
Keyword(s):  
Gas Turbines ◽  
First Generation ◽  
Performance Modeling ◽  
Fixed Bed ◽  
Cost Savings ◽  
Steam Injection ◽  
Combined Cycle ◽  
Total Power ◽  
Fluid Bed ◽  
Combined Cycles

First-generation biomass integrated-gasifier/gas turbine (BIG/GT) technology, based on combined cycles and fluid-bed gasifiers, is likely to be commercially ready by the turn of the century, with ten or more commercially-oriented demonstration projects presently ongoing worldwide. In development and demonstration efforts to date, relatively little attention has been given to alternative cycle configurations or gasifier designs. Performance modeling is described here for steam-injected and combined cycle systems built around gas turbines resembling the GE LM2500, with fuel delivered from integrated fluid- or fixed-bed gasifiers. Some features of fixed-bed gasification appear to offer benefits, particularly for steam-injected cycles. A primary motivation for examining steam injection is expected capital cost savings compared to combined cycles, especially at total power plant capacities below 100 MW. (due to scale economies associated with steam bottoming cycles). Because of the inherently dispersed nature of biomass production, first-generation BIG/GT applications in the sub-100 MW. range will be common.

scholarly journals Part Load Operation of a Combined Plant Using a Closed Circuit Blade Cooled Gas Turbine

1999 ◽  
Author(s):  
Shin’ya Marushima ◽  
Shin’ichi Higuchi ◽  
Takashi Ikeguchi
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Pressure Loss ◽  
Rotor Blade ◽  
Steam Pressure ◽  
Combined Cycle ◽  
Closed Circuit ◽  
Part Load ◽  
Hot Gas ◽  
Combined Cycles

Closed circuit blade cooled gas turbines are drawing attention because of their efficiency compared with that of a conventional air cooled gas turbine. In a closed circuit blade cooled gas turbine, coolant is not discharged into the gas path, so dilution of the hot gas stream, rotor blade pumping loss and pressure loss due to mixing of coolant with the stream are drastically reduced. In this paper, two types of combined cycles, a closed circuit steam cooled gas turbine combined cycle CCSC, and a closed circuit air cooled gas turbine combined cycle CCAC are analyzed to verify the part load performance. The blade temperatures of both combined cycles are lower than at full load, that is, the blades are sufficiently cooled. Under 30% load in the CCSC, the coolant steam pressure is lower than the main gas stream because of a shortage of coolant steam.

Sign in / Sign up

Export Citation Format

Share Document