scholarly journals The Effect of Discrete Pilot Hydrogen Dopant Injection on the Lean Blowout Performance of a Model Gas Turbine Combustor

1999 ◽  
Author(s):  
Oanh Nguyen ◽  
Scott Samuelsen
Keyword(s):  
Gas Turbine ◽  
Atmospheric Pressure ◽  
Gas Turbines ◽  
Nox Emissions ◽  
Gas Turbine Combustor ◽  
Lean Blowout ◽  
Lean Combustion ◽  
Attractive Option ◽  
Overall Performance ◽  
Model Gas Turbine Combustor

In view of increasingly stringent NOx emissions regulations on stationary gas turbines, lean combustion offers an attractive option to reduce reaction temperatures and thereby decrease NOx production. Under lean operation, however, the reaction is vulnerable to blowout. It is herein postulated that pilot hydrogen dopant injection, discretely located, can enhance the lean blowout performance without sacrificing overall performance. The present study addresses this hypothesis in a research combustor assembly, operated at atmospheric pressure, and fired on natural gas using rapid mixing injection, typical of commercial units. Five hydrogen injector scenarios are investigated. The results show that (1) pilot hydrogen dopant injection, discretely located, leads to improved lean blowout performance and (2) the location of discrete injection has a significant impact on the effectiveness of the doping strategy.

Development of a Small-Scale Catalytic Gas Turbine Combustor

1982 ◽  
Vol 104 (1) ◽  
pp. 52-57 ◽  
Author(s):  
S. J. Anderson ◽  
M. A. Friedman ◽  
W. V. Krill ◽  
J. P. Kesselring
Keyword(s):  
Steady State ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Combustion Efficiency ◽  
Small Scale ◽  
Time Interval ◽  
Nox Emissions ◽  
Fuel Injector ◽  
Gas Turbine Combustor ◽  
Opposed Jet

Catalytically supported thermal combustion can provide low NOx emissions with gaseous and distillate fuels while maintaining high combustion efficiency. For stationary gas turbines, catalytic combustion may be the only emerging technology that can cost effectively meet recent federal regulations for NOx emissions. Under EPA sponsorship, a small-scale, catalytic gas turbine combustor was developed to evaluate transient and steady state combustor performance. The combustor consisted of a multiple air-atomizing fuel injector, an opposed jet igniter, and a graded-cell monolithic reactor. System startup, including opposed jet ignition and catalyst stabilization, was achieved in 250 seconds. This time interval is comparable to conventional gas turbines. Steady state operation was performed at 0.505 MPa (5 atmospheres) pressure and 15.3 m/s (50 ft/s) reference velocities. Thermal NOx emissions were measured below 10 ppmv, while fuel NOx conversion ranged from 75 to 95 percent. At catalyst bed temperatures greater than 1422K (2100°F), total CO and UHC emissions were less than 50 ppmv indicating combustion efficiency greater than 99.9 percent. Compared with conventional gas turbine combustors, the catalytic reactor operates only within a relatively narrow range of fuel/air ratios. As a result, modified combustor air distribution or fuel staging will be required to achieve the wide turndown required in large stationary systems.

scholarly journals Evaluation of a Premixed, Prevaporized Gas Turbine Combustor for No. 2 Distillate

1977 ◽  
Author(s):  
D. P. Teixeira ◽  
D. J. White ◽  
M. E. Ward
Keyword(s):  
Heat Capacity ◽  
Gas Turbine ◽  
Air Temperature ◽  
Gas Turbines ◽  
Electric Utility ◽  
Nox Emissions ◽  
Pressure Condition ◽  
Control Potential ◽  
Gas Turbine Combustor ◽  
Current Generation

Results of a series of tests on a prevaporized, premixed combustor to evaluate its emissions control potential while operating on No. 2 distillate oil are presented. The concept utilized the heat capacity of the combustor inlet air to absorb the heat of vaporization of the fuel. Tests were conducted at combustor inlet temperatures and pressures characteristic of current generation electric utility gas turbines (345 C and 10 atm). NOx emissions in excess of proposed EPA gas turbine standards (75 ppm at 15 percent O) were observed at the 10 atm pressure condition and are believed to be the result of incomplete evaporation of the fuel Attempts to increase vaporization rates by increasing inlet air temperature were limited by autoignition of the mixture in the fuel preparation ports.

scholarly journals Influence of Residence Time on Fuel Spray Sauter Mean Diameter (SMD) and Emissions Using Biodiesel and its Blends in a Low NOx Gas Turbine Combustor

2016 ◽  
Author(s):  
Mohamed A. Altaher ◽  
Hu Li ◽  
Gordon E. Andrews
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Fuel Spray ◽  
Inlet Temperature ◽  
Nox Emissions ◽  
Gaseous Emissions ◽  
Low Carbon ◽  
Sauter Mean Diameter ◽  
Gas Turbine Combustor ◽  
Mean Diameter

Biodiesels have advantages of low carbon footprint, reduced toxic emissions, improved energy supply security and sustainability and therefore attracted attentions in both industrial and aero gas turbines sectors. Industrial gas turbine applications are more practical biodiesels due to low temperature waxing and flow problems at altitude for aero gas turbine applications. This paper investigated the use of biodiesels in a low NOx radial swirler, as used in some industrial low NOx gas turbines. A waste cooking oil derived methyl ester biodiesel (WME) was tested on a radial swirler industrial low NOx gas turbine combustor under atmospheric pressure, 600K air inlet temperature and reference Mach number of 0.017&0.023. The pure WME, its blends with kerosene (B20 and B50) and pure kerosene were tested for gaseous emissions and lean extinction as a function of equivalence ratio for both Mach numbers. Sauter Mean Diameter (SMD) of the fuel spray droplets was calculated. The results showed that the WME and its blends had lower CO, UHC emissions and higher NOx emissions than the kerosene. The weak extinction limits were determined for all fuels and B100 has the lowest value. The higher air velocity (at Mach = 0.023) resulted in smaller SMDs which improved the mixing and atomizing of fuels and thus led to reductions in NOx emissions.

Lean/Lean Staged Low NOx Combustion for Near Stoichiometric Gas Turbine Primary Zone Conditions

2001 ◽  
Author(s):  
M. C. Mkpadi ◽  
G. E. Andrews ◽  
I. Khan ◽  
M. N. Mohd Jaafar ◽  
M. Pourkashanian ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Atmospheric Pressure ◽  
Equivalence Ratio ◽  
Fuel Injection ◽  
Nox Emissions ◽  
Two Stage ◽  
Second Stage ◽  
Lean Combustion ◽  
Primary Zone ◽  
Low Nox Combustion

A two-stage lean/lean primary zone at simulated atmospheric pressure gas turbine combustion conditions was shown to give low NOx emissions at atmospheric pressure and 600K inlet temperature. All the combustion air was admitted to the first lean stage, where very lean <5ppm low NOx combustion occurred. A 40mm outlet diameter radial swirler with radial vane passage fuel injection was used in the first stage. After completion of this first stage lean combustion, second stage of fuel injection with no associated air occurred 320mm downstream of the primary swirler outlet, using 76mm radially inward wall injection. This was followed by a dump flow expansion to a 140mm diameter combustor. This provided an expansion shear layer and associated turbulence to mix the second stage fuel with the outlet products from the primary swirl combustion. The second stage fuel burned in the depleted oxygen (∼12%) from the first stage, but still remained a lean combustion zone overall. This design was intended to achieve engine power variation using the second stage fuel. The use of the second stage fuel was shown to reduce the NOx emissions by 50% compared with injecting all of the fuel into the first stage radial swirler. Emission levels of NOx at a first stage swirler equivalence ratio of 0.4 were below 5ppm and at an overall primary zone equivalence ratio of 0.8 with the two stage fuel injection, NOx emissions were about 20ppm. The second stage flame radial distribution of equivalence ratio and emissions was determined by gas analysis. The second stage NOx formation was predicted using CFD with flamelet modelling, with a flamelet strain library computed for 12% oxygen combustion. The mole fraction profile of NOx and combustion temperatures for a range of strain rates in the second stage were predicted. NOx emissions at 0.65 equivalence ratio overall was predicted to be 23ppm at 15% oxygen compared with 16ppm measured. Improved second stage fuel mixing is required to achieve lower NOx emissions and the use of wall turbulators is recommended.

scholarly journals Gas Turbine Co-Firing of Steelworks Ammonia With Coke Oven Gas or Methane: A Fundamental and Cycle Analysis

2019 ◽  
Author(s):  
S. G. Hewlett ◽  
A. Valera-Medina ◽  
D. G. Pugh ◽  
P. J. Bowen
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Numerical Study ◽  
Rankine Cycle ◽  
Coke Oven ◽  
Inlet Temperature ◽  
Ammonia Vapor ◽  
Coke Oven Gas ◽  
Gas Turbine Combustor ◽  
Model Gas Turbine Combustor

Abstract Following on from successful experimental trials employing ammonia/hydrogen blends in a model gas turbine combustor, with favorable NOx and unburned fuel emissions, a detailed numerical study has been undertaken to assess the viability of using steelworks by-product ammonia in gas turbines. Every metric ton (tonne) of steel manufactured using a blast furnace results in approximately 1.5 kg of by-product ammonia, usually present in a vapor form, from the cleansing of coke oven gas (COG). This study numerically investigates the potential to utilize this by-product for power generation. Ammonia combustion presents some major challenges, including poor reactivity and a propensity for excessive NOx emissions. Ammonia combustion has been shown to be greatly enhanced through the addition of support fuels, hydrogen and methane (both major components of COG). CHEMKIN-PRO is employed to demonstrate the optimal ratio of ammonia vapor, and alternatively anhydrous ammonia recovered from the vapor, to COG or methane at equivalence ratios between 1.0 and 1.4 under an elevated inlet temperature of 550K. Aspen Plus was used to design a Brayton-Rankine cycle with integrated recuperation, and overall cycle efficiencies were calculated for a range of favorable equivalence ratios, identified from the combustion models. The results have been used to specify a series of emissions experiments in a model gas turbine combustor.

scholarly journals Coal Gaseous Fueled, Low Fuel-NOx Gas Turbine Combustor

1990 ◽  
Author(s):  
M. Sato ◽  
T. Ninomiya ◽  
T. Nakata ◽  
T. Yoshine ◽  
M. Yamada ◽  
...  
Keyword(s):  
Power Generation ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Coal Gasification ◽  
Combustion Method ◽  
Combined Cycle ◽  
Gas Turbine Combustor ◽  
Lean Combustion ◽  
Combustion Technology ◽  
Fuel Nox

From the view point of future coal utilization technology for the thermal power generation systems, the coal gasification combined cycle system has drawn special interest recently. In the coal gasification combined cycle power generation system, it is necessary to develop a high temperature gas turbine combustor using a low–BTU gas (LBG) which has high thermal efficiency and low emissions. In Japan a development program on the coal gasification combined cycle power generation system has started in 1985 by the national government and Japanese electric companies. In this program, is planned to develop the 1300 °C class gas turbines. However, in the case of using a hot type fuel gas cleaning system, the coal gas fuel to be supplied to gas turbines will contain ammonia. Ammonia will be converted to nitric oxides in the combustion process in gas turbines. Therefore, low fuel–NOx combustion technology is one of the most important research subjects. This paper describes low fuel–NOx combustion technology for 1300 °C class gas turbine combustor using low BTU coal gas fuel. Authors have showed that the rich–lean combustion method is effective to decrease fuel–NOx (1). In general in rich–lean combustion method, the fuel–NOx decreases, as the primary zone becomes richer. But flameholding becomes very difficult in even rich primary zone. For this reason this combustor was designed to have a flameholder with pilot flame. Combustion tests were conducted by using a full scale combustor used in 150 MW gas turbine at the atmospheric pressure condition.

Combustion Technology for Low-Emissions Gas-Turbines: Some Recent Modeling Results

1996 ◽  
Vol 118 (3) ◽  
pp. 201-208 ◽  
Author(s):  
S. M. Correa ◽  
I. Z. Hu ◽  
A. K. Tolpadi
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Spectroscopic Data ◽  
Physical Models ◽  
Gas Turbine Combustor ◽  
Finite Rate ◽  
Recent Developments ◽  
Combustion Technology ◽  
Computationally Intensive ◽  
Transport Method

Computer modeling of low-emissions gas-turbine combustors requires inclusion of finite-rate chemistry and its intractions with turbulence. The purpose of this review is to outline some recent developments in and applications of the physical models of combusting flows. The models reviewed included the sophisticated and computationally intensive velocity-composition pdf transport method, with applications shown for both a laboratory flame and for a practical gas-turbine combustor, as well as a new and computationally fast PSR-microstructure-based method, with applications shown for both premixed and nonpremixed flames. Calculations are compared with laserbased spectroscopic data where available. The review concentrates on natural-gas-fueled machines, and liquid-fueled machines operating at high power, such that spray vaporization effects can be neglected. Radiation and heat transfer is also outside the scope of this review.

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