Improvement of Selective Catalytic Reduction System Performance in Combined Cycle Power Plants

2003 ◽  
Author(s):  
Anatoly Sobolevskiy ◽  
Tom Czapleski ◽  
Richard Murray
Keyword(s):  
Selective Catalytic Reduction ◽  
Mass Flow ◽  
System Performance ◽  
Gas Turbines ◽  
Power Plants ◽  
Catalytic Reduction ◽  
Active Material ◽  
Combined Cycle ◽  
Nox Emissions ◽  
Scr System

Environmental regulations are very stringent in the U.S., requiring very low emissions of nitrogen oxides (NOx) from combined cycle power plants. Selective Catalytic Reduction (SCR) systems utilizing vanadium pentoxide (V2O5) as the active material in the catalyst are a proven method of reducing NOx emissions in the exhaust stack of gas turbines with heat recovery steam generators (HRSG) to 2–4 ppmvd. These low NOx emissions levels require an increase of SCR removal efficiency to the level of 90+ % with limited ammonia slip. The distribution of flow velocities, temperature, and NOx mass flow at the inlet of the SCR are critical to minimizing NOx and ammonia (NH3) concentrations in HRSG stack. The short distance between the ammonia injection grid and the catalyst in the HRSG complicates the achievement of homogeneous NH3 and NOx mixture. To better understand the influence of the above factors on overall SCR system performance, field testing of combined cycle power plants with an SCR installed in the HRSG has been conducted. Uniformity of exhaust flow, temperature and NOx emissions upstream and downstream of the SCR were examined and the results served as a basis for SCR system tuning in order to increase its efficiency. NOx mass flow profiles upstream and downstream of the SCR were used to assess ammonia distribution enhancement. Ammonia flow adjustments within a cross section of the exhaust gas duct yielded significantly improved NOx mass flow uniformity after the SCR while reducing ammonia consumption. Based on field experience, a procedure for ammonia distribution grid tuning was developed and recommendations for SCR performance improvement were generated.

Experimental Study on Low Load Operation Range Extension by Autothermal On-Board Syngas Generation

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Max H. Baumgärtner ◽  
Thomas Sattelmayer
Keyword(s):  
Mass Flow ◽  
Power Output ◽  
Gas Turbines ◽  
Power Plants ◽  
Renewable Energy Sources ◽  
Thermal Power ◽  
Combined Cycle ◽  
Range Extension ◽  
Nox Emissions ◽  
Low Load

Volatile renewable energy sources induce power supply fluctuations. These need to be compensated by flexible conventional power plants. Gas turbines in combined cycle power plants adjust the power output quickly but their turn-down ratio is limited by the slow reaction kinetics, which leads to CO and unburned hydrocarbon emissions. To extend the turn-down ratio, part of the fuel can be converted to syngas, which exhibits a higher reactivity. By an increasing fraction of syngas in the fuel, the reactivity of the mixture is increased and total fuel mass flow and the power output can be reduced. An autothermal on-board syngas generator in combination with two different burner concepts for natural gas (NG)/syngas mixtures was presented in a previous study (Baumgärtner, M. H., and Sattelmayer, T., 2017, “Low Load Operation Range Extension by Autothermal On-Board Syngas Generation,” ASME J. Eng. Gas Turbines Power, 140(4), p. 041505). The study at hand shows a mass-flow variation of the reforming process with mass flows, which allow for pure syngas combustion and further improvements of the two burner concepts which result in a more application-oriented operation. The first of the two burner concepts comprises a generic swirl stage with a central lance for syngas injection. Syngas is injected with swirl to avoid a negative impact on the total swirl intensity and nonswirled. The second concept includes a central swirl stage with an outer ring of jets. For this burner, syngas is injected in both stages to avoid NOx emissions from the swirl stage. Increased NOx emissions produced by NG combustion of the swirl pilot were reported in last year's paper. For both burners, combustion performance is analyzed by OH*-chemiluminescence and gaseous emissions. The lowest possible adiabatic flame temperature without a significant increase of CO emissions was 170–210 K lower for the syngas compared to low load pure NG combustion. This corresponds to a decrease of 15–20% in terms of thermal power.

Experimental Study on Low Load Operation Range Extension by Autothermal On-Board Syngas Generation

2018 ◽  
Author(s):  
Max H. Baumgärtner ◽  
Thomas Sattelmayer
Keyword(s):  
Natural Gas ◽  
Mass Flow ◽  
Power Output ◽  
Gas Turbines ◽  
Power Plants ◽  
Combined Cycle ◽  
Nox Emissions ◽  
Gas Combustion ◽  
Low Load ◽  
Natural Gas Combustion

Volatile renewable energy sources induce power supply fluctuations. These need to be compensated by flexible conventional power plants. Gas turbines in combined cycle power plants adjust the power output quickly but their turn-down ratio is limited by the slow reaction kinetics which lead to CO and unburned hydrocarbon (UHC) emissions. To extend the turn-down ratio, part of the fuel can be converted to syngas, which exhibits a higher reactivity. By an increasing fraction of syngas in the fuel, the reactivity of the mixture is increased and total fuel mass-flow and the power output can be reduced. An Autothermal On-board Syngas Generator in combination with two different burner concepts for natural gas/syngas mixtures was presented in a previous study [1]. The study at hand shows a mass-flow variation of the reforming process with mass-flows which allow for pure syngas combustion and further improvements of the two burner concepts which result in a more application-oriented operation. The first of the two burner concepts comprises a generic swirl stage with a central lance for syngas injection. Syngas is injected with swirl to avoid a negative impact on the total swirl intensity and non-swirled. The second concept includes a central swirl stage with an outer ring of jets. For this burner, syngas is injected in both stages to avoid NOx emissions from the swirl stage. Increased NOx emissions produced by natural gas combustion of the swirl pilot was reported in last year’s paper. For both burners, combustion performance is analyzed by OH*-chemiluminescence and gaseous emissions. The lowest possible adiabatic flame temperature without a significant increase of CO emissions was 170 K – 210 K lower for the syngas compared to low load pure natural gas combustion. This corresponds to a decrease of 15–20 % in terms of thermal power.

Combined Cycle Plants With Frame 9F Gas Turbines

1991 ◽  
Vol 113 (4) ◽  
pp. 475-481 ◽  
Author(s):  
P. Lugand ◽  
C. Parietti
Keyword(s):  
Power Generation ◽  
Flue Gas ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Catalytic Reduction ◽  
Pressure Level ◽  
Combined Cycle ◽  
Size Factor ◽  
Nox Emissions ◽  
Steam Generators

The new 200 MW class MS 9001F gas turbines allow combined cycle plants to reach even higher output levels and greater efficiency ratings. Size factor and higher firing temperatures, with a three-pressure level steam reheat cycle, offer plant efficiencies in excess of 53 percent. Heat recovery steam generators have been designed to accommodate catalytic reduction elements limiting flue gas NOx emissions to as low as 10 ppm VD (15 percent O2). A range of steam turbine models covers the different possible configurations. Various arrangements based on the 350 or 650 MW power generation modules can be optimally configured to the requirements of each site.

Observer-Based Estimation of Aging Condition for Selective Catalytic Reduction Systems in Vehicle Applications

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Yao Ma ◽  
Junmin Wang
Keyword(s):  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Estimation Error ◽  
Nox Reduction ◽  
Observer Design ◽  
Accurate Estimation ◽  
Nox Emissions ◽  
Aging Condition ◽  
Entire Vehicle ◽  
Scr System

This paper presents two observers for estimating the aging condition of selective catalytic reduction (SCR) systems in vehicle applications. SCR systems have been widely recognized as one of the leading engine exhaust gas aftertreatment systems for reducing diesel powertrain tailpipe NOx emissions in ground vehicle applications. While fresh SCRs are quite effective in reducing tailpipe NOx emissions, their NOx reduction capabilities and performances may substantially degrade with in-service aging. To maintain the emission control performance of a SCR system for a diesel engine during the entire vehicle service life, it is thus critical to have an accurate estimation of the SCR system aging condition. In this paper, two Lyapunov-based observers utilizing the measurements of NOx and ammonia concentrations are analytically developed and verified in simulations for estimating the SCR aging condition. The measurement uncertainty is explicitly considered in the observer design process. A sufficient condition for the boundedness of the estimation error is derived. Simulation results under the US06 test cycle demonstrate the effectiveness of the proposed observers.

scholarly journals Combined Cycle Plants With Frame 9F Gas Turbines

1990 ◽  
Author(s):  
P. Lugand ◽  
C. Parietti
Keyword(s):  
Power Generation ◽  
Flue Gas ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Catalytic Reduction ◽  
Pressure Level ◽  
Combined Cycle ◽  
Size Factor ◽  
Nox Emissions ◽  
Steam Generators

The new 200 MW-class MS 9001F gas turbines allow combined cycle plants to reach even higher output levels and greater efficiency ratings. Size factor and higher firing temperatures, with a 3-pressure level steam reheat cycle, offer plant efficiencies in excess of 53 %. Heat recovery steam generators have been designed to accommodate catalytic reduction elements limiting flue gas NOx emissions to as low as 10 ppm VD (15 % O2). A range of steam turbine models covers the different possible configurations. Various arrangements based on the 350 or 650 MW power generation modules can be optimally configured to the requirements of each site.

scholarly journals Reaction Pathways and Kinetics for Selective Catalytic Reduction (SCR) of Acidic NOx Emissions from Power Plants with NH3

ACS Catalysis ◽  
2017 ◽  
Vol 7 (12) ◽  
pp. 8358-8361 ◽  
Author(s):  
Minghui Zhu ◽  
Jun-Kun Lai ◽  
Uma Tumuluri ◽  
Michael E. Ford ◽  
Zili Wu ◽  
...  
Keyword(s):  
Selective Catalytic Reduction ◽  
Power Plants ◽  
Catalytic Reduction ◽  
Reaction Pathways ◽  
Nox Emissions

The Effects of Changing Fuels on Hot Gas Path Conditions in Syngas Turbines

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
Adrian S. Sabau ◽  
Ian G. Wright
Keyword(s):  
Mass Flow ◽  
Gas Turbines ◽  
Power Plants ◽  
Open Circuit ◽  
Combined Cycle ◽  
Coolant Flow ◽  
Allowable Limit ◽  
Flow Rates ◽  
Cooling Flows ◽  
Hot Gas

Gas turbines in integrated gasification combined cycle power plants burn a fuel gas (syngas (SG)) in which the proportions of hydrocarbons, H2, CO, water vapor, and minor impurity levels may differ significantly from those in natural gas (NG). Such differences can yield changes in the temperature, pressure, and corrosive species that are experienced by critical components in the hot gas path, with important implications for the design, operation, and reliability of the turbine. A new data structure and computational methodology is presented for the numerical simulation of a turbine thermodynamic cycle, with emphasis on the hot gas path components. The approach used allows efficient handling of turbine components and variable constraints due to fuel changes. Examples are presented for a turbine with four stages, in which the vanes and blades are cooled in an open circuit using air from the appropriate compressor stages. For an imposed maximum metal temperature, values were calculated for the fuel, air, and coolant flow rates and through-wall temperature gradients for cases where the turbine was fired with NG or SG. A NG case conducted to assess the effect of coolant pressure matching between the compressor extraction points and corresponding turbine injection points indicated that this is a feature that must be considered for high combustion temperatures. The first series of SG simulations was conducted using the same inlet mass flow and pressure ratios as those for the NG case. The results showed that higher coolant flow rates and a larger number of cooled turbine rows were needed for the SG case to comply with the imposed temperature constraints. Thus, for that case, the turbine size would be different for SG than for NG. A second series of simulations examined scenarios for maintaining the original turbine configuration (i.e., geometry, diameters, blade heights, angles, and cooling circuit characteristics) used for the SG simulations. In these, the inlet mass flow was varied while keeping constant the pressure ratios and the amount of hot gas passing the first vane of the turbine. The effects of turbine matching between the NG and SG cases were increases—for the SG case of approximately 7% and 13% for total cooling flows and cooling flows for the first-stage vane, respectively. In particular, for the SG case, the vanes in the last stage of the turbine experienced inner wall temperatures that approached the maximum allowable limit.

Sequential Combustion in Ansaldo Energia Gas Turbines: The Technology Enabler for CO2-Free, Highly Efficient Power Production Based on Hydrogen

2020 ◽  
Author(s):  
Andrea Ciani ◽  
John P. Wood ◽  
Anders Wickström ◽  
Geir J. Rørtveit ◽  
Rosetta Steeneveldt ◽  
...  
Keyword(s):  
Power Generation ◽  
Free Energy ◽  
Gas Turbines ◽  
Carbon Capture ◽  
Power Plants ◽  
Carbon Capture And Storage ◽  
Combined Cycle ◽  
Fuel Flexibility ◽  
Combustion Technology ◽  
And Storage

Abstract Today gas turbines and combined cycle power plants play an important role in power generation and in the light of increasing energy demand, their role is expected to grow alongside renewables. In addition, the volatility of renewables in generating and dispatching power entails a new focus on electricity security. This reinforces the importance of gas turbines in guaranteeing grid reliability by compensating for the intermittency of renewables. In order to achieve the Paris Agreement’s goals, power generation must be decarbonized. This is where hydrogen produced from renewables or with CCS (Carbon Capture and Storage) comes into play, allowing totally CO2-free combustion. Hydrogen features the unique capability to store energy for medium to long storage cycles and hence could be used to alleviate seasonal variations of renewable power generation. The importance of hydrogen for future power generation is expected to increase due to several factors: the push for CO2-free energy production is calling for various options, all resulting in the necessity of a broader fuel flexibility, in particular accommodating hydrogen as a future fuel feeding gas turbines and combined cycle power plants. Hydrogen from methane reforming is pursued, with particular interest within energy scenarios linked with carbon capture and storage, while the increased share of renewables requires the storage of energy for which hydrogen is the best candidate. Compared to natural gas the main challenge of hydrogen combustion is its increased reactivity resulting in a decrease of engine performance for conventional premix combustion systems. The sequential combustion technology used within Ansaldo Energia’s GT36 and GT26 gas turbines provides for extra freedom in optimizing the operation concept. This sequential combustion technology enables low emission combustion at high temperatures with particularly high fuel flexibility thanks to the complementarity between its first stage, stabilized by flame propagation and its second (sequential) stage, stabilized by auto-ignition. With this concept, gas turbines are envisaged to be able to provide reliable, dispatchable, CO2-free electric power. In this paper, an overview of hydrogen production (grey, blue, and green hydrogen), transport and storage are presented targeting a CO2-free energy system based on gas turbines. A detailed description of the test infrastructure, handling of highly reactive fuels is given with specific aspects of the large amounts of hydrogen used for the full engine pressure tests. Based on the results discussed at last year’s Turbo Expo (Bothien et al. GT2019-90798), further high pressure test results are reported, demonstrating how sequential combustion with novel operational concepts is able to achieve the lowest emissions, highest fuel and operational flexibility, for very high combustor exit temperatures (H-class) with unprecedented hydrogen contents.

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