Investigation on NOx of a Low Emission Combustor Design With Multihole Premixer-Prevaporizer

2004 ◽  
Author(s):  
Yuzhen Lin ◽  
Yunhui Peng ◽  
Gaoen Liu
Keyword(s):  
Great Influence ◽  
Nox Emission ◽  
Emissions Reduction ◽  
Inlet Temperature ◽  
Main Stage ◽  
Nox Emissions ◽  
Baseline Design ◽  
Air Mixing ◽  
Reduction Of Nox ◽  
Two Stages

A low NOx emission combustor design was presented in this paper. The design features the premixer-prevaporizer tube with multihole and two stages arranged radially in line, with the outer stage being pilot stage and inner stage being main stage. The multihole premixer and prevaporizer is a part of main stage. The results of NOx emission were provided and also compared with the baseline design that the premixer and prevaporizer tube without multihole. The double swirler prefilming airblast atomizer was installed in the premixed prevaporized duct entrance. The mean drop size and radial fuel flux distribution were measured to determine proper configurations of the multihole premixer-prevaporizer. NOx emission investigations were carried out using a test combustor with one pilot stage and one main stage under the operating condition of high inlet temperature (800K) and inlet air pressure was atmospheric pressure. The experiment results demonstrated large NOx emissions reduction of the multihole premixer-prevaporizer compared with the baseline design. The more even fuel-air mixing, which was gained by the multiple jets, intensified the fuel and air mixing within the premixer-prevaporizer, resulted in the large reduction of NOx emission. The configurations of multihole premixer-prevaporizer had great influence on NOx emissions reduction.

Investigation of H2/CH4-Air Flame Characteristics of a Micromix Model Burner at Atmosphere Pressure Condition

2018 ◽  
Author(s):  
Xunwei Liu ◽  
Weiwei Shao ◽  
Yong Tian ◽  
Yan Liu ◽  
Bin Yu ◽  
...  
Keyword(s):  
Hydrogen Content ◽  
Gas Turbines ◽  
Turbulent Flame ◽  
Experimental Studies ◽  
Nox Emission ◽  
Inlet Temperature ◽  
Nox Emissions ◽  
High Hydrogen ◽  
Atmosphere Pressure ◽  
Turbulent Flame Speed

For high-hydrogen-content fuel, the Micromix Combustion Technology has been developed as a potential low NOx emission solution for gas turbine combustors, especially for advanced gas turbines with high turbine inlet temperature. Compared with conventional lean premixed flames, multiple distributed slim and micro flames could lead to a lower NOx emission performance for shortening residence time of high temperature flue gas and generally a more uniform temperature distribution. This work aims at micromix flame characteristics of a model burner fueled with hydrogen blending with methane under atmosphere pressure conditions. The model burner assembly was designed to have six concentrically millimeter-sized premixed units around a same unit centrally. Numerical and experimental studies were conducted on mixing performance, flame stability, flame structure and CO/NOx emissions of the model burner. OH radical distribution by OH-PLIF and OH chemiluminescence (OH*) imaging were employed to analyze the turbulence-reaction interactions and characters of the reaction zone at the burner exit. Micromix flames fueled with five different hydrogen content H2-CH4 (60/40, 50/50, 40/60, 30/70, 0/100 Vol.%) were investigated, along with the effects of equivalence ratio and heat load. Results indicated that low NOx emissions of less than 10 ppm (@15% O2) below the exhaust temperature of 1920 K were obtained for all the different fuels. Combustion oscillation didn’t occur for all the conditions. It was found that at a constant flame temperature, the higher the hydrogen content of the fuel, the higher the turbulent flame speed and the weaker the flame lift effect. Combustion noise and NOx emissions also increase with increasing hydrogen content. The OH/OH* signal distribution indicated that a pure methane micromix flame showed a lifted and weaken distributed feature.

Low NOx Emission Technology for the Vx4.3A Gas Turbine Series in Fuel Oil Operation

2002 ◽  
Author(s):  
Juergen Meisl ◽  
Gerald Lauer ◽  
Stefan Hoffmann
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Nox Emission ◽  
Fuel Oil ◽  
Liquid Fuels ◽  
Nox Emissions ◽  
Premix Combustion ◽  
Reduction Of Nox ◽  
Low Nox Emission ◽  
Distillate Fuel

This contribution describes the systematic refinement of the hybrid burner used in Siemens Vx4.3A gas turbines for lean premix combustion of various liquid fuels such as Distillate fuel No. 2, Naphtha and Condensate. Additionally to the dry premix operation fuel/water emulsions are used in premix mode for a further reduction of NOx emissions or power augmentation. NOx emissions of less than 72 ppm are already achieved with the HR3 hybrid burner in dry premix mode. These can be reduced to values below of 42 ppm NOx in emulsion mode.

Numerical Prediction of NOx Emission and Exit Temperature Pattern in a Model Staged Lean Premixed Prevaporized Combustor

2013 ◽  
Author(s):  
Man Zhang ◽  
Hao Wu ◽  
Hao Wang
Keyword(s):  
Temperature Distribution ◽  
Numerical Prediction ◽  
Droplet Breakup ◽  
Nox Emission ◽  
Pollutant Emission ◽  
Temperature Pattern ◽  
Main Stage ◽  
Nox Emissions ◽  
Two Phase ◽  
Exit Temperature

Steady-state Reynolds Averaged Navier-Stokes (RANS) equations are solved in the present numerical investigation to simulate the reactive two-phase flow in a model aero-engine combustor, and the reactive flow field with NOx emissions is analyzed. The gaseous phase is modeled by the modified SST turbulence model, and the liquid phase is modeled by Lagrangian tracking method considering the droplet breakup, collision and evaporation. Turbulence-combustion interaction is modeled by the extended coherent flame model, and NOx emissions are modeled by solving the species transport equation based on the assumption of frozen temperature. The fuel system of the present simulated combustor is radially staged, with a main stage employing the principle of lean prevaporized and premixed (LPP) concept to reduce pollutant emission, and a pilot stage burning a diffusion flame for flame stability. For the exit temperature quality improvement, dilution air is assigned with little amount of airflow. Detailed numerical results including exit temperature distribution, dominant burning performances and species distributions are evaluated for the combustion with and without dilution air. The influence of upstream burning characteristics to downstream temperature distribution is assessed. Numerical prediction of NOx emission demonstrates its capability of a reasonable reduction, and the exit temperature pattern with the dilution air is also able to fulfill its design target.

scholarly journals Nonlinear responses of particulate nitrate to NO<sub>x</sub> emission controls in the megalopolises of China

2021 ◽  
Vol 21 (19) ◽  
pp. 15135-15152
Author(s):  
Mengmeng Li ◽  
Zihan Zhang ◽  
Quan Yao ◽  
Tijian Wang ◽  
Min Xie ◽  
...  
Keyword(s):  
Emission Reduction ◽  
Fine Particulate Matter ◽  
Eastern China ◽  
Yangtze River Delta ◽  
Nitrate Pollution ◽  
Nox Emission ◽  
Nox Emissions ◽  
Nonlinear Responses ◽  
Emission Controls ◽  
Reduction Of Nox

Abstract. Nitrate is an increasingly important component of fine particulate matter (PM2.5) in Chinese cities. The production of nitrate is not only related to the abundance of its precursor, but it is also supported by the atmospheric photochemical oxidants, raising a new challenge for the current emission control actions in China. This paper uses comprehensive measurements and a regional meteorology–chemistry model with optimized mechanisms to establish the nonlinear responses between particulate nitrate and the emission controls of nitrogen oxides (NOx) in the megalopolises of China. Nitrate is an essential component of PM2.5 in eastern China, accounting for 9.4 %–15.5 % and 11.5 %–32.1 % of the PM2.5 mass for the warm and cold seasons. The hypothetical NOx emission reduction scenarios (−10 % to −80 %) during summer–autumn result in almost linearly lower PM2.5 by −2.2 % in Beijing–Tianjin–Hebei (BTH) and −2.9 % in Yangtze River Delta (YRD) per 10 % reduction of NOx emissions, whereas they lead to a rather complicated response of PM components in winter. Wintertime nitrate is found to increase by +4.1 % in BTH and +5.1 % in YRD per 10 % reduction of NOx emissions, with nearly unchanged nitric acid (HNO3) and higher dinitrogen pentoxide (N2O5) intermediate products produced from the increased atmospheric oxidant levels. An inflexion point appears at 30 %–50 % NOx emission reduction, and a further reduction in NOx emissions is predicted to cause −10.5 % reduction of nitrate for BTH and −7.7 % for YRD per 10 % reduction of NOx emissions. In addition, the 2012–2016 NOx control strategy actually leads to no changes or even increases of nitrate in some areas (8.8 % in BTH and 14.4 % in YRD) during winter. Our results also emphasize that ammonia (NH3) and volatile organic compounds (VOCs) are effective in controlling nitrate pollution, whereas decreasing the sulfur dioxide (SO2) and NOx emissions may have counterintuitive effects on nitrate aerosols. This paper helps understand the nonlinear aerosol and photochemistry feedbacks and defines the effectiveness of proposed mitigations for the increasingly serious nitrate pollution in China.

CFD Prediction and Design of Low NOx Radial Swirler Systems

2009 ◽  
Author(s):  
Phil T. King ◽  
Gordon E. Andrews ◽  
Myeong N. Kim ◽  
Mohamed Pourkashanian ◽  
Andy C. McIntosh
Keyword(s):  
Fuel Injection ◽  
Laminar Flame ◽  
Turbulent Flame ◽  
Inlet Temperature ◽  
Nox Emissions ◽  
Flamelet Model ◽  
Flame Thickness ◽  
Flame Development ◽  
Air Mixing ◽  
Dissipation Model

A radial swirler with vane passage fuel injection using a radial fuel spoke with one fuel hole per passage was investigated using CFD at 0.5 equivalence ratio and 600K inlet temperature at 1 bar. Experimental measurements of the internal flame composition from water cooled gas sample probes were the experimental results used for comparison. Three combustion models were compared: flamelet with two difference kinetic schemes; PDF transport with two step chemistry and finite rate eddy dissipation model. Both models consistently underpredicted the turbulent flame thickness to 90% heat release by a factor of about 2. The PDF model with postprocessing NOx predictions over estimated the NOx emissions considerably and the best model was the flamelet model with full chemistry. The under prediction of the turbulent reaction zone thickness was concluded to be due to inadequate modelling of strained flame quenching for very lean flames with large laminar flame thickness and very low burning velocities. This flamelet model was applied to predict the influence of the radial swirler outlet geometry on the flame development, fuel and air mixing and NOx emissions. A dump expansion from the radial swirler outlet was compared with the addition of a shroud at the outlet and with the addition of a 60mm long outlet throat. The shroud was shown to increase the peak turbulence and confine it very close to the shroud lip. This improved the fuel and air mixing and lowered the predicted NOx from 2.7ppm to 1.2ppm with the shrouded swirler and 0.3ppm with the 60mm outlet throat and mixing length.

scholarly journals Selective Catalyst Reduction (SCR) using Zeolite for Reduction of NOx Emissions in C.I. Engines

2021 ◽  
Author(s):  
Ayush Dwivedi ◽  
Hemraj Chaudhary ◽  
Venkateshwarlu Chintala ◽  
Ashish Karn
Keyword(s):  
Direct Injection ◽  
Nox Emission ◽  
Complete Analysis ◽  
Time Interval ◽  
Nox Emissions ◽  
Selective Catalyst ◽  
Reduction Of Nox ◽  
Ci Engine ◽  
Catalyst Reduction ◽  
Scr System

The current study is aimed for reduction of NOx emission (oxides of nitrogen) from a direct injection CI engine by SCR (selective catalytic reduction) technology. The SCR system was developed originally at the (CAER) Centre for alternate and renewable energy in which zeolite was used as a catalyst. The developed SCR system was integrated with a single chamber direct injection CI engine of 3.7 kW rated power at 1500 rpm. Experimental tests results revealed the significant reduction of NOx emission with SCR system at all engine loads. Experimental design of the investigation typified obtaining standard behaviour of the engine i.e., without SCR followed by engine's information after the presentation of SCR framework. It is investigated from the exploratory tests results that hydrocarbon (HC) emission was highest about 20ppm at 10kg load yet at 4kg load it decreased to 16ppm. Carbon monoxide (CO) emission was moderately increased with SCR system. NOx emission are minimum with SCR at all engine loading conditions as compared to without SCR system. An experimental time study is also done &amp; readings being taken in the time interval of 5 minutes. A difference of 10ppm hydrocarbon emission has been measured in between 15-20 minutes. In the NOx emissions, a difference of 97 ppm has been observed while using the SCR system. Henceforth, the introduction of SCR to the engine minimizes the emissions &amp; enhance the combustion performance along with the benefit of reduction in NOx emissions. After the complete analysis of the data, the outcomes demonstrate a positive impact on the selective catalyst reduction (SCR) system set up with the engine.

Influence of Main Swirler Vane Angle on the Ignition Performance of TeLESS-II Combustor

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Bo Wang ◽  
Chi Zhang ◽  
Yuzhen Lin ◽  
Xin Hui ◽  
Jibao Li
Keyword(s):  
High Speed ◽  
Inlet Temperature ◽  
Main Stage ◽  
Ignition Process ◽  
High Speed Camera ◽  
Fuel Distribution ◽  
Fuel Droplets ◽  
Planar Laser ◽  
Cfd Method ◽  
Vane Angle

In order to balance the low emission and wide stabilization for lean premixed prevaporized (LPP) combustion, the centrally staged layout is preferred in advanced aero-engine combustors. However, compared with the conventional combustor, it is more difficult for the centrally staged combustor to light up as the main stage air layer will prevent the pilot fuel droplets arriving at igniter tip. The goal of the present paper is to study the effect of the main stage air on the ignition of the centrally staged combustor. Two cases of the main swirler vane angle of the TeLESS-II combustor, 20 deg and 30 deg are researched. The ignition results at room inlet temperature and pressure show that the ignition performance of the 30 deg vane angle case is better than that of the 20 deg vane angle case. High-speed camera, planar laser induced fluorescence (PLIF), and computational fluids dynamics (CFD) are used to better understand the ignition results. The high-speed camera has recorded the ignition process, indicated that an initial kernel forms just adjacent the liner wall after the igniter is turned on, the kernel propagates along the radial direction to the combustor center and begins to grow into a big flame, and then it spreads to the exit of the pilot stage, and eventually stabilizes the flame. CFD of the cold flow field coupled with spray field is conducted. A verification of the CFD method has been applied with PLIF measurement, and the simulation results can qualitatively represent the experimental data in terms of fuel distribution. The CFD results show that the radial dimensions of the primary recirculation zone of the two cases are very similar, and the dominant cause of the different ignition results is the vapor distribution of the fuel. The concentration of kerosene vapor of the 30 deg vane angle case is much larger than that of the 20 deg vane angle case close to the igniter tip and along the propagation route of the kernel, therefore, the 30 deg vane angle case has a better ignition performance. For the consideration of the ignition performance, a larger main swirler vane angle of 30 deg is suggested for the better fuel distribution when designing a centrally staged combustor.

A Critical Review of NOx Correlations for Gas Turbine Combustors

1975 ◽  
Author(s):  
D. A. Sullivan ◽  
P. A. Mas
Keyword(s):  
Experimental Data ◽  
Data Base ◽  
Gas Turbine ◽  
Critical Review ◽  
Inlet Temperature ◽  
Nox Emissions ◽  
Empirical Correlations ◽  
Gas Turbine Combustors ◽  
Semi Empirical ◽  
Adequate Data

The effect of inlet temperature, pressure, air flowrate and fuel-to-air ratio on NOx emissions from gas turbine combustors has received considerable attention in recent years. A number of semi-empirical and empirical correlations relating these variables to NOx emissions have appeared in the literature. They differ both in fundamental assumptions and in their predictions. In the present work, these simple NOx correlations are compared to each other and to experimental data. A review of existing experimental data shows that an adequate data base does not exist to evaluate properly the various NOx correlations. Recommendations are proposed to resolve this problem in the future.

Effects of fuel-air mixing on flame structures and NOx emissions in swirling methane jet flames

1998 ◽  
Vol 27 (1) ◽  
pp. 1229-1237 ◽  
Author(s):  
T.S. Cheng ◽  
Y.-C. Chao ◽  
D.-C. Wu ◽  
T. Yuan ◽  
C.-C. Lu ◽  
...  
Keyword(s):  
Nox Emissions ◽  
Jet Flames ◽  
Air Mixing ◽  
Flame Structures

A Study of the NOx Emission in a Regenerative Industrial Furnace

2001 ◽  
Author(s):  
Qing Jiang ◽  
Chao Zhang
Keyword(s):  
Mixture Fraction ◽  
Combustion Process ◽  
Nox Emission ◽  
Moment Closure ◽  
Combustion Model ◽  
Industrial Furnace ◽  
Low Emission ◽  
Reduction Of Nox ◽  
Closure Method ◽  
Probability Density Function Pdf

Abstract A study of the nitrogen oxides (NOx) emission and combustion process in a gas-fired regenerative, high temperature, low emission industrial furnace has been carried out numerically. The effect of two additives, methanol (CH3OH) and hydrogen peroxide (H2O2), to fuel on the NOx emission has been studied. A moment closure method with the assumed β probability density function (PDF) for mixture fraction is used in the present work to model the turbulent non-premixed combustion process in the furnace. The combustion model is based on the assumption of instantaneous full chemical equilibrium. The results showed that CH3OH is effective in the reduction of NOx in a regenerative industrial furnace. However, H2O2 has no significant effect on the NOx emission.

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