Low NOx Emission From an Ambient Pressure Diffusion Flame Fired Gas Turbine Cycle (APGC)

2002 ◽  
Vol 125 (1) ◽  
pp. 46-50
Author(s):  
G. Vermes ◽  
L. E. Barta ◽  
J. M. Bee´r
Keyword(s):  
Gas Turbine ◽  
Diffusion Flame ◽  
Power Plants ◽  
Ambient Pressure ◽  
Nox Emission ◽  
Heat Extraction ◽  
Operating Pressure ◽  
Nox Formation ◽  
Experimental Development ◽  
Gas Turbine Cycle

The prospects of reduced NOx emission, improved efficiency, stable, and oscillation-free combustion, and reduced construction costs achieved by an “Inverted Brayton Cycle” applied to midsize (0.5 to 5.0 MWe) power plants are discussed. In this cycle, the combustion products of an atmospheric pressure combustor are expanded in the gas turbine to subatmospheric pressure and following heat extraction are compressed back to slightly above the atmospheric, sufficient to enable a controlled fraction of the exhaust gas to be recirculated to the combustor. Due to the larger volume flow rate of the gas, the polytropic efficiency of both the turbine and compressor of this small machine is increased. Because of the low operating pressure and flue gas recirculation, both of which are instrumental to low NOx formation, the combustor can be operated in the diffusion flame mode; this, on the other hand, assures good flame stability and oscillation-free combustion over wide ranges of the operating variables. For the task of obtaining very low NOx formation, the well-tested multi annular swirl burner (MASB) is chosen. Recent computational and experimental development of the MASB by Siemens-Westinghouse as a topping combustor is discussed. It is shown that the MASB operated in rich-quench-lean mode is capable of single-digit NOx emission. The emissions are further lowered in the APGC by ambient pressure combustion, and by the injection of the recirculated gas in the quench zone of the combustor. Results of a computational optimization study of the ambient pressure gas turbine cycle (APGC) are presented.

Natural Gas Decarbonization to Reduce CO2 Emission From Combined Cycles—Part II: Steam-Methane Reforming

2000 ◽  
Vol 124 (1) ◽  
pp. 89-95 ◽  
Author(s):  
G. Lozza ◽  
P. Chiesa
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Partial Oxidation ◽  
Power Plants ◽  
Combined Cycle ◽  
Performance Estimation ◽  
Thermodynamic Efficiency ◽  
Methane Reforming ◽  
Operating Pressure ◽  
Carbon Conversion

This paper discusses novel schemes of combined cycle, where natural gas is chemically treated to remove carbon, rather than being directly used as fuel. Carbon conversion to CO2 is achieved before gas turbine combustion. The first part of the paper discussed plant configurations based on natural gas partial oxidation to produce carbon monoxide, converted to carbon dioxide by shift reaction and therefore separated from the fuel gas. The second part will address methane reforming as a starting reaction to achieve the same goal. Plant configuration and performance differs from the previous case because reforming is endothermic and requires high temperature heat and low operating pressure to obtain an elevated carbon conversion. The performance estimation shows that the reformer configuration has a lower efficiency and power output than the systems addressed in Part I. To improve the results, a reheat gas turbine can be used, with different characteristics from commercial machines. The thermodynamic efficiency of the systems of the two papers is compared by an exergetic analysis. The economic performance of natural gas fired power plants including CO2 sequestration is therefore addressed, finding a superiority of the partial oxidation system with chemical absorption. The additional cost of the kWh, due to the ability of CO2 capturing, can be estimated at about 13–14 mill$/kWh.

scholarly journals Thermodynamic Analysis of Different Configurations of Combined Cycle Power Plants

2015 ◽  
Vol 5 (2) ◽  
pp. 89
Author(s):  
Munzer S. Y. Ebaid ◽  
Qusai Z. Al-hamdan
Keyword(s):  
Gas Turbine ◽  
Power Plants ◽  
Combined Cycle ◽  
Cycle Performance ◽  
Maximum Efficiency ◽  
Specific Work ◽  
Slight Effect ◽  
Turbine Engine ◽  
Gas Turbine Cycle ◽  
Cycle Efficiency

<p class="1Body">Several modifications have been made to the simple gas turbine cycle in order to increase its thermal efficiency but within the thermal and mechanical stress constrain, the efficiency still ranges between 38 and 42%. The concept of using combined cycle power or CPP plant would be more attractive in hot countries than the combined heat and power or CHP plant. The current work deals with the performance of different configurations of the gas turbine engine operating as a part of the combined cycle power plant. The results showed that the maximum CPP cycle efficiency would be at a point for which the gas turbine cycle would have neither its maximum efficiency nor its maximum specific work output. It has been shown that supplementary heating or gas turbine reheating would decrease the CPP cycle efficiency; hence, it could only be justified at low gas turbine inlet temperatures. Also it has been shown that although gas turbine intercooling would enhance the performance of the gas turbine cycle, it would have only a slight effect on the CPP cycle performance.</p>

Recuperators in Gas Turbine Systems

1998 ◽  
Author(s):  
Esa Utriainen ◽  
Bengt Sundén
Keyword(s):  
Research And Development ◽  
Gas Turbine ◽  
Cross Sections ◽  
Heat Exchangers ◽  
Power Plants ◽  
Pressure Ratio ◽  
Compact Heat Exchangers ◽  
Thermodynamic Cycles ◽  
Large Pressure ◽  
Gas Turbine Cycle

The application of recuperators in advanced thermodynamic cycles is growing due to stronger demands of low emissions of pollutants and the necessity of improving the cycle efficiency of power plants to reduce the fuel consumption. This paper covers applications and types of heat exchangers used in gas turbine units. The trends of research and development are brought up and the future need for research and development is discussed. Material aspects are covered to some extent. Attempts to achieve compact heat exchangers for these applications are also discussed. With the increasing pressure ratio in the gas turbine cycle, large pressure differences between the hot and cold sides exist. This has to be accounted for. The applicability of CFD (Computational Fluid Dynamics) is discussed and a CFD–approach is presented for a specific recuperator. This recuperator has narrow wavy ducts with complex cross-sections and the hydraulic diameter is so small that laminar flow prevails. The thermal-hydraulic performance is of major concern.

scholarly journals Modeling of advanced fossil fuel power plants

2021 ◽  
Author(s):  
Farshid Zabihian
Keyword(s):  
Power Generation ◽  
Gas Turbine ◽  
Power Plants ◽  
Fossil Fuel ◽  
Specific Power ◽  
Operating Pressure ◽  
Utilization Factor ◽  
Fuel Switching ◽  
Wide Range ◽  
Cycle Efficiency

The first part of this thesis deals with greenhouse gas (GHG) emissions from fossil fuel-fired power stations. The GHG emission estimation from fossil fuel power generation industry signifies that emissions from this industry can be significantly reduced by fuel switching and adaption of advanced power generation technologies. In the second part of the thesis, steady-state models of some of the advanced fossil fuel power generation technologies are presented. The impacts of various parameters on the solid oxide fuel cell (SOFC) overpotentials and outputs are investigated. The detail analyses of operation of the hybrid SOFC-gas turbine (GT) cycle when fuelled with methane and syngas demonstrate that the efficiencies of the cycles with and without anode exhaust recirculation are close, but the specific power of the former is much higher. The parametric analysis of the performance of the hybrid SOFC-GT cycle indicates that increasing the system operating pressure and SOFC operating temperature and fuel utilization factor improves cycle efficiency, but the effects of the increasing SOFC current density and turbine inlet temperature are not favourable. The analysis of the operation of the system when fuelled with a wide range of fuel types demonstrates that the hybrid SOFC-GT cycle efficiency can be between 59% and 75%, depending on the inlet fuel type. Then, the system performance is investigated when methane as a reference fuel is replaced with various species that can be found in the fuel, i.e., H₂, CO₂, CO, and N₂. The results point out that influence of various species can be significant and different for each case. The experimental and numerical analyses of a biodiesel fuelled micro gas turbine indicate that fuel switching from petrodiesel to biodiesel can influence operational parameters of the system. The modeling results of gas turbine-based power plants signify that relatively simple models can predict plant performance with acceptable accuracy. The unique feature of these models is that they are developed based on similar assumptions and run at similar conditions; therefore, their results can be compared. This work demonstrates that, although utilization of fossil fuels for power generation is inevitable, at least in the short- and mid-term future, it is possible and practical to carry out such utilization more efficiently and in an environmentally friendlier manner.

scholarly journals Thermodynamic Cycle Concepts for High-Efficiency Power Plans. Part A: Public Power Plants 60+

2019 ◽  
Vol 11 (2) ◽  
pp. 554 ◽  
Author(s):  
Krzysztof Kosowski ◽  
Karol Tucki ◽  
Marian Piwowarski ◽  
Robert Stępień ◽  
Olga Orynycz ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Carbon Dioxide Emissions ◽  
Power Plants ◽  
High Efficiency ◽  
Thermodynamic Cycle ◽  
Economic Resilience ◽  
Public Power ◽  
Pass System ◽  
Classical Gas ◽  
Gas Turbine Cycle

An analysis was carried out for different thermodynamic cycles of power plants with air turbines. Variants with regeneration and different cogeneration systems were considered. In the paper, we propose a new modification of a gas turbine cycle with the combustion chamber at the turbine outlet. A special air by-pass system of the combustor was applied and, in this way, the efficiency of the turbine cycle was increased by a few points. The proposed cycle equipped with a regenerator can provide higher efficiency than a classical gas turbine cycle with a regenerator. The best arrangements of combined air–steam cycles achieved very high values for overall cycle efficiency—that is, higher than 60%. An increase in efficiency to such degree would decrease fuel consumption, contribute to the mitigation of carbon dioxide emissions, and strengthen the sustainability of the region served by the power plant. This increase in efficiency might also contribute to the economic resilience of the area.

Modeling of Gas Turbine-Based Cogeneration System

2012 ◽  
Author(s):  
Farshid Zabihian ◽  
Alan S. Fung ◽  
Fabio Schuler
Keyword(s):  
Power Plant ◽  
Gas Turbine ◽  
Power Plants ◽  
Superheated Steam ◽  
Hot Water ◽  
Cogeneration System ◽  
Exhaust Stream ◽  
Low Efficiency ◽  
Gas Turbine Cycle ◽  
Wasted Energy

Gas turbine-based power plants generate a significant portion of world’s electricity. This paper presents the modeling of a gas turbine-based cogeneration cycle. One of the reasons for the relatively low efficiency of a single gas turbine cycle is the waste of high-grade energy at its exhaust stream. In order to recover this wasted energy, steam and/or hot water can be cogenerated to improve the cycle efficiency. In this work, a cogeneration power plant is introduced to use this wasted energy to produce superheated steam for industrial processes. The cogeneration system model was developed based on the data from the Whitby cogeneration power plant in ASPEN PLUS®. The model was validated against the operational data of the existing power plant. The electrical and total (both electrical and thermal) efficiencies were around 40% and 70% (LHV), respectively. It is shown that cogenerating electricity and steam not only significantly improve the general efficiency of the cycle but it can also recover the output and efficiency losses of the gas turbine as a result of high ambient temperature by generating more superheated steam. Furthermore, this work shows that the model could capture the operation of the systems with an acceptable accuracy.

Thermodynamic Study of Humid Air Gas Turbine Cycle Power Plants

2005 ◽  
Author(s):  
R. Yadav ◽  
P. Sreedhar Yadav
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
Substantial Reduction ◽  
Thermodynamic Study ◽  
Humid Air ◽  
Turbine Plant ◽  
Design Engineers ◽  
Gas Turbine Plant ◽  
Gas Turbine Cycle

The major challenges before the design engineers of a gas turbine plant and its variants are the enhancement of power output, substantial reduction in NOx emission and improvement in plant thermal efficiency. There are various possibilities to achieve these objectives and humid air gas turbine cycle power plant is one of them. The present study deals with the thermodynamic study of humid air gas turbine cycle power plants based on first law. Using the modeling and governing equations, the parametric study has been carried out. The results obtained will be helpful in designing the humid air gas turbines, which are used as peaking units. The comparison of performance of humid air gas turbine cycle shows that it is superior to basic gas turbine cycle but inferior and more complex to steam injected cycle.

Effect of Deaerator Parameters on Simple and Reheat Gas/Steam Combined Cycle With Different Cooling Medium

2019 ◽  
Author(s):  
Mayank Maheshwari ◽  
Onkar Singh
Keyword(s):  
Gas Turbine ◽  
Mass Fraction ◽  
Power Plants ◽  
Performance Enhancement ◽  
Pressure Ratio ◽  
Combined Cycle ◽  
Cycle Performance ◽  
Inlet Temperature ◽  
Operating Pressure ◽  
Cooling Medium

Abstract Performance of gas/steam combined cycle power plants relies upon the performance exhibited by both gas based topping cycle and steam based bottoming cycle. Therefore, the measures for improving the performance of the gas turbine cycle and steam bottoming cycle eventually result in overall combined cycle performance enhancement. Gas turbine cooling medium affects the cooling efficacy. Amongst different parameters in the steam bottoming cycle, the deaerator parameter also plays its role in cycle performance. The present study analyzes the effect of deaerator’s operating pressure being varied from 1.6 bar to 2.2 bar in different configurations of simple and reheat gas/steam combined cycle with different cooling medium for fixed cycle pressure ratio of 40, turbine inlet temperature of 2000 K and ambient temperature of 303 K with varying ammonia mass fraction from 0.6 to 0.9. Analysis of the results obtained for different combined cycle configuration shows that for the simple gas turbine and reheat gas turbine-based configurations, the maximum work output of 643.78 kJ/kg of air and 730.87 kJ/kg of air respectively for ammonia mass fraction of 0.6, cycle efficiency of 54.55% and 53.14% respectively at ammonia mass fraction of 0.7 and second law efficiency of 59.71% and 57.95% respectively at ammonia mass fraction of 0.7 is obtained for the configuration having triple pressure HRVG with ammonia-water turbine at high pressure and intermediate pressure and steam turbine operating at deaerator pressure of 1.6 bar.

Effects of Burner Interaction on NOx Emission From Swirl Premix Burner in a Gas Turbine Combustor

2014 ◽  
Author(s):  
Cheon Hyeon Cho ◽  
Chae Hoon Sohn ◽  
Ju Hyeong Cho ◽  
Han Seok Kim
Keyword(s):  
Gas Turbine ◽  
Nox Emission ◽  
Gas Turbine Combustor ◽  
Step Size ◽  
Flow Temperature ◽  
Nox Formation ◽  
Air Stream ◽  
Flow Interactions ◽  
Model Chamber ◽  
Wall Interaction

Flame interaction between neighboring burners in a gas turbine combustor is investigated numerically for pursuit of its effect on NOx emission from the burners. In a model chamber or liner, EV burners with double cone are installed. Two burners with the same rotating direction of air stream are adopted and the distance between them is variable from 74.2 mm to 222.6 mm by the step size of 37.1 mm. Gaseous methane and air are adopted as fuel and oxidizer, respectively. From steady-state numerical analyses, flow, temperature, and NO concentration fields are calculated in all computational cases to find their correlation with NOx formation. NOx emission is evaluated at the exit of the model chamber with two burners as a function of burner distance and compared with that from a single burner. In all cases of two-burner calculations, NOx emission is higher than that of a single burner, which results from flow interactions between neighboring burners as well as between a burner and a liner wall. NOx emission is affected significantly by flow and flame interactions between them and strongly depends on burner distance. Burner interaction is divided into two regimes of a burner-burner interaction and a burner-wall interaction depending on the distance. In the former regime, NOx emission is reduced as flame interaction between burners is enhanced and in the latter regime, it is also reduced as interaction between the burner and the liner wall is enhanced.

Combustion Characteristics and NOX Emission of Hydrogen-Rich Fuel Gases at Gas Turbine Relevant Conditions

2012 ◽  
Author(s):  
Y.-C. Lin ◽  
S. Daniele ◽  
P. Jansohn ◽  
K. Boulouchos
Keyword(s):  
Gas Turbine ◽  
Turbulent Combustion ◽  
Turbulent Flame ◽  
Elevated Pressure ◽  
Chemical Kinetic ◽  
Nox Emission ◽  
Operating Pressure ◽  
High Hydrogen ◽  
Turbulent Flame Speed ◽  
Fuel Mixtures

In this paper, characteristics of turbulent combustion and NOx emission for high hydrogen-content fuel gases (H2 > 70 vol. %; “hydrogen-rich”) are addressed. An experimental investigation is performed in a perfectly-premixed axial-dump combustor under gas turbine relevant conditions. Fundamental features of turbulent combustion for these mixtures are evaluated based on OH-PLIF diagnostics. On the other hand, NOx emissions are measured with an exhaust gas sampling probe positioned downstream the combustor outlet. Compared to syngas mixtures (H2 + CO), the operational limits for hydrogen-rich fuel gases are found to occur at even leaner conditions concerning flashback phenomena. With respect to effects of operating pressure, a strongly reduced operational envelope is observed at elevated pressure. Only with decreasing the preheat temperature a viable approach to further extend the operational range is seen. Evaluation of the averaged turbulent flame shape shows that the profile of the flame front is generally approaching that of an ideal cone. Thus a simplified approach for estimating the turbulent flame speed via the location of the flame tip alone can be applied. The level of NOx emission for the hydrogen-rich fuel mixtures is generally above that of syngas mixtures, which exhibit already higher NOx emission values than natural gas. Distinct chemical kinetic features are found specifically at elevated pressure. While the pressure effects are weak for syngas, a non-monotonic behavior is observed for the hydrogen-rich fuels. Reaction path analysis is performed to complement and provide more insight to the findings from the measurements. From chemical kinetic calculations a distinct shift in NOx formation pathways (thermal NOx vs. NOx through N2O/NNH reaction channels) can be observed for the different fuel mixtures at different pressure levels.

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