Development Potential of Combined-Cycle (GUD) Power Plants With and Without Supplementary Firing

1992 ◽  
Vol 114 (4) ◽  
pp. 653-659 ◽  
Author(s):  
H. H. Finckh ◽  
H. Pfost
Keyword(s):  
Steam Generator ◽  
Heat Recovery ◽  
Power Plants ◽  
Plant Size ◽  
Combined Cycle ◽  
Nox Emissions ◽  
Heat Recovery Steam Generator ◽  
Low Emission ◽  
Combined Cycles ◽  
Interesting Alternative

Unfired combined cycles achieve superior efficiencies at low emission levels. The potential and efficiency limits are investigated and the possibilities for enhancing efficiency are described. It is demonstrated that limited supplementary firing of the heat recovery steam generator can be an interesting alternative and that this allows efficiency and plant size to be increased. The effects of supplementary firing on NOx emissions are also shown.

scholarly journals Development Potential of Combined-Cycle (GUD) Power Plants With and Without Supplementary Firing

1991 ◽  
Author(s):  
H. H. Finckh ◽  
H. Pfost
Keyword(s):  
Steam Generator ◽  
Heat Recovery ◽  
Power Plants ◽  
Plant Size ◽  
Combined Cycle ◽  
Nox Emissions ◽  
Heat Recovery Steam Generator ◽  
Low Emission ◽  
Combined Cycles ◽  
Interesting Alternative

Unfired combined cycles achieve superior efficiencies at low emission levels. The potential and efficiency limits are investigated and the possibilities for enhancing efficiency are described. It is demonstrated that limited supplementary firing of the heat recovery steam generator can be an interesting alternative and that this allows efficiency and plant size to be increased. The effects of supplementary firing on NOx emissions are also shown.

scholarly journals Gas Turbine Heat Recovery Steam Generators for Combined Cycles Natural or Forced Circulation Considerations

1988 ◽  
Author(s):  
Akber Pasha
Keyword(s):  
Gas Turbine ◽  
Steam Generator ◽  
Heat Recovery ◽  
Power Plants ◽  
Natural Circulation ◽  
Combined Cycle ◽  
Heat Recovery Steam Generator ◽  
Steam Generators ◽  
Forced Circulation ◽  
Gas Turbine Exhaust

In recent years the combined cycle has become a very attractive power plant arrangement because of its high cycle efficiency, short order-to-on-line time and flexibility in the sizing when compared to conventional steam power plants. However, optimization of the cycle and selection of combined cycle equipment has become more complex because the three major components, Gas Turbine, Heat Recovery Steam Generator and Steam Turbine, are often designed and built by different manufacturers. Heat Recovery Steam Generators are classified into two major categories — 1) Natural Circulation and 2) Forced Circulation. Both circulation designs have certain advantages, disadvantages and limitations. This paper analyzes various factors including; availability, start-up, gas turbine exhaust conditions, reliability, space requirements, etc., which are affected by the type of circulation and which in turn affect the design, price and performance of the Heat Recovery Steam Generator. Modern trends around the world are discussed and conclusions are drawn as to the best type of circulation for a Heat Recovery Steam Generator for combined cycle application.

Design, Part Load and Transient Operation of Combined Cycle Plants With Water Flashing

1995 ◽  
Author(s):  
P. J. Dechamps
Keyword(s):  
High Pressure ◽  
Steam Generator ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Vapour Phase ◽  
Pressure Level ◽  
Combined Cycle ◽  
Saturated Steam ◽  
Heat Recovery Steam Generator ◽  
Combined Cycles

The last decade has seen remarkable improvement in gas turbine based power generation technologies, with the increasing use of natural gas-fuelled combined cycle units in various regions of the world. The struggle for efficiency has produced highly complex combined cycle schemes based on heat recovery steam generators with multiple pressure levels and possibly reheat. As ever, the evolution of these schemes is the result of a technico-economic balance between the improvement in performance and the increased costs resulting from a more complex system. This paper looks from the thermodynamic point of view at some simplified combined cycle schemes based on the concept of water flashing. In such systems, high pressure saturated water is taken off the high pressure drum and flashed into a tank. The vapour phase is expanded as low pressure saturated steam or returned to the heat recovery steam generator for superheating, whilst the liquid phase is recirculated through the economizer. With only one drum and three or four heat exchangers in the boiler as in single pressure level systems, the plant might have a performance similar to that of a more complex dual pressure level system. Various configurations with flash tanks are studied based on commercially available 150 MW-class E-technology gas turbines and compared with classical multiple pressure level combined cycles. Reheat units are covered, both with flash tanks and as genuine combined cycles for comparison purposes. The design implications for the heat recovery steam generator in terms of heat transfer surfaces are emphasized. Off-design considerations are also covered for the flash based schemes, as well as transient performances of these schemes, because the simplicity of the flash systems compared to normal combined cycles significantly affects the dynamic behaviour of the plant.

scholarly journals The Optimization of Combined Cycle HRSGs as a Function of the Plant Load Duty

1996 ◽  
Author(s):  
P. J. Dechamps
Keyword(s):  
Power Generation ◽  
Steam Generator ◽  
Heat Recovery ◽  
Power Plants ◽  
Combined Cycle ◽  
Load Factor ◽  
Heat Recovery Steam Generator ◽  
Economic Optimization ◽  
Cost Of Electricity ◽  
The Cost

Natural gas fired combined cycle power plants now take a substantial share of the power generation market, mainly because they can be delivering power with a remarkable efficiency shortly after the decision to install is taken, and because they are a relatively low capital cost option. The power generation markets becoming more and more competitive in terms of the cost of electricity, the trend is to go for high performance equipments, notably as far as the gas turbine and the heat recovery steam generator are concerned. The heat recovery steam generator is the essential link in the combined cycle plant, and should be optimized with respect to the cost of electricity. This asks for a techno-economic optimization with an objective function which comprises both the plant efficiency and the initial investment. This paper applies on an example the incremental cost method, which allows to optimize parameters like the pinch points and the superheat temperatures. The influence of the plant load duty on this optimization is emphasized. This is essential, because the load factor will not usually remain constant during the plant life-time. The example which is presented shows the influence of the load factor, which is important, as the plant goes down in merit order with time, following the introduction of more modern, more efficient power plants on the same grid.

Repowering an Existing Power Generating Plant

2003 ◽  
Author(s):  
Mohammad R. Shahnazari ◽  
Abbas Abbassi
Keyword(s):  
Steam Turbine ◽  
Steam Generator ◽  
Heat Recovery ◽  
Power Plants ◽  
Combined Cycle ◽  
Heat Recovery Steam Generator ◽  
Combined Cycle Plant ◽  
The Cost

A common repowering option is converting a fossil-fired steam unit to a gas-fired combined-cycle plant by addition of a combustion turbine and a Heat Recovery Steam Generator. In this approach the existing steam turbine and related auxiliaries are typically retained and some plant modification is applied. This paper intends to study this option for two old power plants. In this study the HRSGs are modeled, designed and their costs are estimated. Total generating cost for both plants are calculated in order to show whether or not the final cost is competitive with the cost of a new combined cycle unit.

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